U.S. patent application number 12/796471 was filed with the patent office on 2010-09-30 for systems and methods for reactor chemistry and control.
This patent application is currently assigned to SUNDROP FUELS, INC.. Invention is credited to Courtland Hilton, Zoran Jovanovic, Donna Kelley, Brittany Lancaster, Andrew Minden, Christopher Perkins, Richard Ridley.
Application Number | 20100242354 12/796471 |
Document ID | / |
Family ID | 42736707 |
Filed Date | 2010-09-30 |
United States Patent
Application |
20100242354 |
Kind Code |
A1 |
Perkins; Christopher ; et
al. |
September 30, 2010 |
SYSTEMS AND METHODS FOR REACTOR CHEMISTRY AND CONTROL
Abstract
A method, apparatus, and system for a solar-driven chemical
plant that manages variations in solar energy are disclosed. Some
embodiments include a solar thermal receiver to absorb concentrated
solar energy, a solar driven chemical reactor contained within the
solar thermal receiver, and an entrained gas biomass feed system
that uses an entrainment carrier gas and supplies a variety of
biomass sources fed as particles into the solar driven chemical
reactor. Inner walls of the solar thermal receiver and the chemical
reactor can be made from materials selected to transfer energy.
Some embodiments include a control system that may be configured to
balance the gasification reaction of biomass particles with the
available concentrated solar energy and additional variable
parameters including, but not limited to, a fixed range of particle
sizes, temperature of the chemical reactor, and residence time of
the particles in a reaction zone in the chemical reactor.
Inventors: |
Perkins; Christopher;
(Boulder, CO) ; Jovanovic; Zoran; (Louisville,
CO) ; Hilton; Courtland; (Broomfield, CO) ;
Lancaster; Brittany; (Boulder, CO) ; Minden;
Andrew; (Boulder, CO) ; Ridley; Richard;
(Loveland, CO) ; Kelley; Donna; (Louisville,
CO) |
Correspondence
Address: |
Rutan & Tucker, LLP.
611 ANTON BLVD, SUITE 1400
COSTA MESA
CA
92626
US
|
Assignee: |
SUNDROP FUELS, INC.
Louisville
CO
|
Family ID: |
42736707 |
Appl. No.: |
12/796471 |
Filed: |
June 8, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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61248282 |
Oct 2, 2009 |
|
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61185492 |
Jun 9, 2009 |
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Current U.S.
Class: |
44/639 ; 252/373;
422/105; 422/110 |
Current CPC
Class: |
C10J 3/485 20130101;
B01J 2219/00117 20130101; Y02P 20/129 20151101; C10G 2300/807
20130101; C10J 3/506 20130101; C10J 3/56 20130101; C10G 2300/1014
20130101; C10G 2300/1025 20130101; C10J 3/54 20130101; C10L 1/04
20130101; B01J 19/0033 20130101; C10J 2300/0976 20130101; Y02E
50/30 20130101; C01B 2203/1685 20130101; C07C 29/1518 20130101;
C10G 2/30 20130101; C10J 2300/0906 20130101; C10J 2300/1284
20130101; C10J 2300/1861 20130101; C10L 2290/42 20130101; B01J
19/245 20130101; C01B 2203/061 20130101; Y02B 40/18 20130101; C01B
3/34 20130101; C01B 2203/84 20130101; C10L 2290/52 20130101; Y02E
10/40 20130101; Y02P 20/145 20151101; Y02T 50/678 20130101; C01B
2203/0811 20130101; C07C 29/15 20130101; C10J 2200/09 20130101;
C10J 2200/15 20130101; C10J 2300/094 20130101; C10J 2300/0973
20130101; C10L 2290/547 20130101; C10G 2/32 20130101; C10J 3/60
20130101; C10L 2290/02 20130101; C10L 2290/50 20130101; C01B 3/22
20130101; C10J 3/482 20130101; C10J 2300/1621 20130101; C10L
2290/06 20130101; C10J 2300/0989 20130101; C10L 2290/28 20130101;
C01B 2203/1241 20130101; C10L 2200/0492 20130101; Y02E 50/10
20130101; C01B 2203/0216 20130101; C10L 2290/04 20130101; C10J 3/00
20130101; C10J 3/723 20130101; C10J 3/62 20130101; Y02P 20/133
20151101; Y02P 30/20 20151101; C01B 2203/0233 20130101; C10J
2300/1223 20130101; C10J 2300/1665 20130101; C10L 2290/08 20130101;
Y02P 20/50 20151101; B01J 19/0013 20130101; C10J 3/721 20130101;
C10J 3/84 20130101; F24S 20/20 20180501; C10J 2300/123 20130101;
C10J 2300/1693 20130101; B01J 19/2445 20130101; C10G 3/00 20130101;
C10J 2200/158 20130101; C10J 3/466 20130101; C10J 2300/0993
20130101; C10J 3/82 20130101; C10J 2300/0916 20130101; C10J 3/58
20130101; C10J 2300/1659 20130101; B01J 2219/00186 20130101; C10J
2300/1292 20130101; C10J 2300/1853 20130101; C10K 1/024 20130101;
C01B 3/384 20130101; C10J 2300/0909 20130101; C07C 29/15 20130101;
C07C 31/04 20130101; C07C 29/1518 20130101; C07C 31/04
20130101 |
Class at
Publication: |
44/639 ; 422/105;
422/110; 252/373 |
International
Class: |
C10L 1/00 20060101
C10L001/00; G05D 7/00 20060101 G05D007/00; C07C 1/02 20060101
C07C001/02 |
Claims
1. A solar-driven chemical plant that manages variations in solar
energy, comprising: a solar thermal receiver aligned to absorb
concentrated solar energy from one or more solar energy sources
including 1) a single mirror, heliostat, or solar-concentrating
dish, 2) an array of heliostats, 3) two or more solar-concentrating
dishes, and 3) any combination of the three; a solar driven
chemical reactor at least partially contained within the solar
thermal receiver; an entrained gas biomass feed system that uses an
entrainment carrier gas and supplies a variety of biomass types fed
as particles into the solar driven chemical reactor; inner walls of
the solar thermal receiver and the chemical reactor made from
materials selected to transfer energy by primarily heat radiation,
along with convection, and conduction to the reacting biomass
particles to drive the endothermic gasification reaction of the
particles of biomass flowing through the chemical reactor; a
control system configured to balance the gasification reaction of
biomass particles with the available concentrated solar energy and
additional variable parameters including a fixed range of particle
sizes, operating temperature of the chemical reactor, and residence
time of the particles in a reaction zone in the chemical reactor so
that an overall biomass particle conversion remains above a
threshold set point of greater than 90 percent of the carbon
content of the particles into reaction products that include
hydrogen and carbon monoxide gas; and a feedforward portion and a
feedback portion of the control system configured to adapt for both
long and short term disturbances in available solar energy, wherein
the feedforward portion anticipates cyclic changes in solar energy
due to at least a time of day, day of the year, short-term cloud,
dust, smoke or other obscuring events, or long-term weather events,
with a predictive model that adapts to the anticipated cyclic
changes, and wherein the feedback portion measures actual process
parameters including the operating temperature of the chemical
reactor and then uses these measurements in the balancing of the
gasification reaction of biomass particles.
2. The solar-driven chemical plant of claim 1, further comprising:
one or more temperature sensors to detect the operating temperature
of the chemical reactor at an entrance and an exit and supply that
measurement to the feedback portion of the control system, two or
more reactor tubes in the chemical reactor in which the biomass
particles flow in and located within the solar thermal receiver,
one or more feed lines which supply to the reactor tubes the
particles of biomass in the fixed range of particle size controlled
to an average smallest dimension size between 50 microns (um) and
2000 um, with a general range of between 200 um and 1000 um,
wherein the control system maintains the temperature of the tubes
of the chemical reactor at a steady state temperature exceeding
1000 degrees C., above transitory minimum temperature of 800
degrees C. and below peak temperatures of 1600 degrees C., wherein
the control system balances the gasification reaction of biomass
particles with the available concentrated solar energy so that the
overall biomass particle conversion temperature remains above a
threshold set point of substantial tar destruction resulting in
less than or equal to 50 mg/Nm 3 of tar and the gasification of
greater than 90 percent of the carbon content of the particles, and
where the residence time of the particles of biomass in the
reaction zone in the chemical reactor is between a range of 0.01
and 5 seconds.
3. The solar-driven chemical plant of claim 1, further comprising:
an amount of solar energy available indicated by one or more
temperature sensors in the chemical reactor and one or more light
meters to provide the actual process parameters information to the
feedback portion of the control system; two or more reactor tubes
in which gasification occurs in a vertical orientation in the
chemical reactor in which the gasification occurs; a separate feed
line is used to feed biomass particles for each of the reactor
tubes in the chemical reactor, which allows independent temperature
control and balancing of amount of particles of biomass flowing in
each of the reactor tubes in the multiple tube solar-driven
chemical reactor; a lock hopper system in the feed system, where
the particles of biomass feed are distributed to the separate
carrier gas entrainment line by the lock hopper feed system, in
which feed rate of the biomass particles is controlled by a
metering device, which responds to a feed demand signal received
from the control system; and an on-site chemical synthesis reactor
that is geographically located on the same site as the chemical
reactor and integrated to receive the hydrogen and carbon monoxide
products from the gasification reaction, wherein the on-site
chemical synthesis reactor has an input to receive the hydrogen and
carbon monoxide products and use them in a hydrocarbon fuel
synthesis process to create one or more of 1) a liquid hydrocarbon
or alcohol fuel, 2) solid fuel, 3) liquid chemicals, 4) solid
chemicals.
4. The solar-driven chemical plant of claim 1, further comprising:
a lock hopper having a metering device in a feed system having one
or more feed lines coupled to the chemical reactor, wherein the
control system sends a feed demand signal to the feed system to
control a feed rate of the particles of biomass in the solar driven
chemical reactor, where control of the multiple reactor tubes is
split into two or more groups of tube subsets, where the control
system balances the amount of biomass particles flowing into each
of the reactor tubes to an amount of solar energy available by 1)
controlling a rotational rate of a screw of a lock hopper feeding
the biomass where all the tubes in the tube subset have their feed
rate simultaneously turned up or turned down, 2) varying an amount
of the reactor tube-subsets participating in the gasification
reaction by turning on or turning off a flow of particles of
biomass from the lock hopper to the reactor tubes making up a tube
subset, or 3) a combination of both.
5. The solar-driven chemical plant of claim 1, further comprising:
a spray nozzle to supply water to the product gas exiting the
chemical reactor to shift some of the product carbon monoxide to
additional hydrogen and carbon dioxide gas in a water gas shift
reaction, making the hydrogen to carbon monoxide ratio appropriate
for the planned syngas use.
6. The solar-driven chemical plant of claim 2, wherein the control
system is configured to balance chemical reaction types, including
the biomass gasification reaction, a stream reforming reaction, a
dry reforming reaction and various combinations of these reactions
within the solar driven chemical reactor, to an amount of
concentrated solar energy available directed at the solar thermal
receiver in order to keep the solar chemical reactor at a
temperature at which the chemical reactor operates high enough to
maintain the generated syngas within a set molar ratio of H2 to CO
ratio of 2.1 to 2.8, with being substantially tar free having less
than 200 Mg/M 3, and having less than 7% by volume CO in the
generated syngas.
7. The solar-driven chemical plant of claim 1, further comprising:
an amount of surface area, thermal mass, and heat capacity is built
into the receiver and can be in the form of the receiver walls,
insulation, or reactor tubes; one or more temperature sensors at
the entrance and/or exit of the reactor tubes; an operational
temperature range of below 1600 degrees C. and above 800 degrees C.
in the chemical reactor during daily weather conditions, which are
subject to rapid changes in solar availability; and a feed demand
signal from the control system to control the feed rate of
particles of biomass in the solar driven chemical reactor by the
feedforward/feedback model-predictive scheme in cooperation with
designing in enough surface area, thermal mass, and heat capacity
in the multiple tubes and receiver cavity to ensure that
temperature of the reactor cavity remains in the operational
temperature range of below 1600 degrees C. and above 800 degrees C.
during the rapidly changing daily weather conditions, wherein the
feed forward model predicts an available solar energy over each
time period in a given day as well as each day throughout the year,
the feedback portion receives dynamic feedback from sensors,
including temperature sensors, and they are combined to maintain
both the quality and output of resultant syngas at above the
threshold set point of substantial tar destruction resulting in
less than or equal to 50 mg/m 3 and complete gasification of
greater than 90 percent of the carbon content of the biomass
particles into the reaction products, wherein the enough surface
area and thermal mass of the cavity and reactor tubes is built into
the multiple tubes and receiver cavity, to act as a ballast,
averaging out very short term small fluctuations (second to second)
in the available solar energy to have a negligible ramp-up and
ramp-down of temperature of the receiver and reactor due to these
instantaneous changes in available solar energy, thereby allowing
the ramp-up and ramp-down of the feed rate of biomass particles to
be more gradual as well.
8. The solar-driven chemical plant of claim 7, further comprising:
an insulation layer around the cavity is set thick enough to
control conduction losses to less than 5% of the peak solar input,
wherein the receiver cavity temperature is a controlled parameter,
which the control system then primarily controls by modulating a
flow rate of biomass particles through the reactor tubes balanced
against the predicted feedforward available amount of solar energy
and the dynamically determined feedback amount of available solar
energy.
9. The solar-driven chemical plant of claim 7, further comprising:
a composition analyzer at the exit of the reactor system to sense
changes in the hydrogen, carbon monoxide, carbon dioxide, methane,
tar composition, or any combination thereof of the syngas, where
the composition analyzer provides a dynamic signal to the feedback
portion of the control system and upon readings of any of the
hydrogen, carbon monoxide, carbon dioxide, methane, tar
compositions of the syngas that are above a threshold, where the
control system sends a signal to divert the reactant products of
the gasification reaction to a recycling line back into the
entrance to the chemical reactor to avoid damage to filters,
compressors, catalytic systems, and other components in the
downstream portions of the solar gasification and/or liquid fuel
and/or chemical synthesis process.
10. The solar-driven chemical plant of claim 1, wherein the biomass
particles being fed from the entrained flow biomass feed system
undergo several distinct chemical processes of the gasification
reaction prior to exiting the reactor tubes including: pyrolysis of
the biomass particles into 1) carbonaceous char and 2) volatile
components vaporized into gas products; gasification of the
carbonaceous char including lignin fractions into gaseous products
including carbon monoxide, hydrogen, and tars; and cracking of the
tars, including larger hydrocarbons and aromatic compounds
collectively known as tars, at greater than 1000 degrees C. to
produce substantial tar destruction resulting in less than or equal
to 50 mg/m 3 and complete gasification of greater than 90 percent
of the carbon content of the biomass particles into reaction
products including hydrogen and carbon monoxide gas, wherein the
steps of complete gasification and cracking of tars starts and
finishes within the residence time of the biomass particles in the
reaction zone in the chemical reactor between the range of 0.01 and
5 seconds.
11. The solar-driven chemical plant of claim 3, further comprising:
one or more detectors indicate an amount of solar energy available
in different areas of the solar receiver to guide the control
system in balancing an amount of the biomass particles flowing in
each of the reactor tubes; a 2-phase pinch valve system on each
feed line to each reactor tube, wherein the control system balances
the amount of biomass particles flowing in each of the reactor
tubes to the amount of solar energy available by sending a dynamic
feedback control signal to the 2-phase pinch valve system to
control an amount of compression of a flexible pipe section of the
feed line that the biomass particles are flowing through to control
flow in the individual reactor tubes, and where the detectors
indicate the amount of solar energy available to guide the control
system; and wherein an on-site fuel synthesis process has an input
to receive a filtered form of the hydrogen and carbon monoxide gas
from the reaction products and process them to store the
concentrated solar energy in chemical bonds of the biomass as an
easily storable and transportable liquid hydrocarbon fuel, where
the liquid hydrocarbon fuel is one or more of jet fuel, DME,
gasoline, diesel, methanol, mixed alcohol, synthetic natural gas,
heating oil, and synthetic crude oil.
12. The solar-driven chemical plant of claim 2, further comprising:
a shape and width of the outlet of the feed line pipe carrying the
biomass particles to its corresponding reactor tube to control a
dispersion pattern of biomass particles entering each reactor tube
and the greater than 90% gasification of the carbon content of the
particles occurs because of both 1) the high operating temperatures
of greater than 1000 degrees C. and 2) that the biomass particles
are well separated from one another in a flowing disperse cloud of
very fine biomass particles; and wherein the resulting CO to CO2
ratio is controllable through a range of greater than or equal to
5:1.
13. The solar-driven chemical plant of claim 2, further comprising:
a material making up the reactor tubes possesses high emissivity of
0.8 emissivity coefficient or better, high thermal conductivity of
30 watts per meter-Kelvin or better, at least moderate heat
capacity of 8 joules per mole-degree Kelvin or better, and is
resistant to the oxidizing air environment in the solar receiver
cavity and the reducing environment of the biomass gasification
reaction inside the tubes in order to support operating
temperatures within the tubes in the tar cracking regime between
800-1350 degrees C., wherein this operating temperature eliminates
any need for tar cracking equipment downstream of the chemical
reactor, and where in addition the operation at the high operating
temperature in the reactor tubes improves heat transfer, minimizes
methane from the exit gases, and decreases required residence time
of the biomass particles to achieve complete gasification, which in
turn decreases a physical size of the chemical reactor itself.
14. The solar-driven chemical plant of claim 2, further comprising:
a material or materials and an indirect solar gasifier design of
the multiple reactor tubes allows for feedstock flexibility in the
type of biomass making up the particles of biomass, and obviates
any need for an exothermic/endothermic reaction balancing in the
chemical reactor design because the concentrated solar energy
drives the endothermic gasification reaction and a radiation-based
heat transfer balancing makes the endothermic reaction gasification
quite forgiving in terms of internal reaction balance, and thus, at
least two or more different types of biomass materials can be used
in the same multiple reactor tube geometry of the chemical reactor,
obviating any need for a complete reengineering when a new type of
biomass feedstock is used, where the two or more different types of
biomass materials that can be fed from the feed system,
individually or in combinational mixtures, are selected from the
group consisting of rice straw, rice hulls, corn stover, switch
grass, wheat straw, miscanthus, orchard wastes, sorghum, forestry
thinnings, forestry wastes, agricultural wastes, source separated
green wastes and other similar biomass sources, as long as a few
parameters are controlled including the particle size of the
biomass and operating temperature of the chemical reactor.
15. The solar-driven chemical plant of claim 2, further comprising:
an insulation layer around the receiver with resistance heaters
connected to the solar receiver walls to assist with maintaining
temperature in the 800-1600 degree C. range, where waste heat from
either the spill of concentrated solar energy not entering the
aperture of the receiver, the solar gasification process, or some
other available heat-producing process, heats a working fluid that
directly or indirectly supplies energy to electrical generation
machinery or heats high-temperature storage material that can be a
solid, liquid, or gas, which will later be used to heat a working
fluid, which directly or indirectly supplies energy to electrical
generation machinery, to supply a source of power for including at
least the resistance heaters, where the control system can turn on
and off the resistance heaters as additional heat sources for
maintaining temperature as need be, wherein the control system
supplies a control signal to 1) the feed system, 2) the solar
energy concentrating fields, 3) and the supplemental resistance
heating system, and wherein the lag times and response times of
the: 1) solar energy concentrating fields to alter alignment and an
amount of concentrated solar energy supplied, 2) feed system to
alter an amount of biomass flowing in the reactor tubes, and 3)
time for weather events to alter an amount of solar energy
available, are factors taken into account by a control algorithm in
the control system in sending out the control signals to the feed
system, the solar energy concentrating fields and the supplemental
resistance heating system.
16. The solar-driven chemical plant of claim 2, further comprising:
a carrier gas supply line that supplies the entrainment gas as a
pressurized dry steam, and/or where natural gas is fed along with
the biomass particles during a co-gasification of 1) biomass in the
presence of steam and 2) steam reforming of natural gas, and the
pressurized dry steam is generated from waste heat recovered from
either the spill of concentrated solar energy not entering an
aperture in the receiver, the solar gasification process, or some
other available heat-producing process.
17. The solar-driven chemical plant of claim 2, wherein the control
system utilize different models that are selected depending on the
system and variable state, and include insolation perturbations
categorized into 3 types: 1) short events, including weather events
in duration from 0-5 hours 2) medium events, including diurnal
events in duration from 5-14 hours, and 3) long-term events in
duration more than 14 hours.
18. The solar-driven chemical plant of claim 2, wherein the
computerized control system is configured to receive a feedback
signal from a set of sensors, an amount of solar energy available
indicated by one or more temperature sensors in the chemical
reactor and one or more light meters provides the actual process
parameters information to the feedback portion of the control
system, a feed vessel in the feed system responds to a feed demand
signal from the computerized control system, and the computerized
control system controls a flow rate of particles of biomass in the
solar-driven chemical reactor based on an amount of solar energy
available indicated by sensors for the chemical reactor.
19. A method of generating syngas products for a solar-driven
chemical plant that manages variations in solar energy, comprising:
focusing concentrated solar energy to a solar driven chemical
reactor contained within the solar thermal receiver; supplying
biomass particles into one or more tubes in the solar driven
chemical reactor; driving an endothermic gasification reaction of
the particles of biomass flowing through the tubes of the chemical
reactor by primarily heat radiation from the inner walls of the
solar thermal receiver and the tube surfaces of the chemical
reactor by the absorbed concentrated solar energy; balancing the
gasification reaction of biomass particles with the available
concentrated solar energy and additional variable parameters of 1)
a fixed range of particle size, 2) operating temperature of the
chemical reactor, and 3) residence time of the particles in a
reaction zone in the chemical reactor so that an overall biomass
particle conversion remains above a threshold set point of
substantial tar destruction resulting in less than or equal to 50
mg/Nm 3 of tar and gasification of greater than 90 percent of the
carbon content of the particles into reaction products that include
hydrogen and carbon monoxide gas; and adapting to short-term
disturbances in duration, medium-term disturbances in duration, and
long-term disturbances in duration in available solar energy,
wherein a control system anticipates changes in solar energy due to
at least a time of day, day of year, periodic meteorological
reports, solar field condition, and biomass type and condition,
with a predictive model that adapts to the anticipated cyclic
changes, and wherein a feedback component measures actual process
parameters including the temperature of the chemical reactor and
uses the these measurements in the balancing the gasification
reaction of biomass particles.
20. A method for a solar driven chemical plant, comprising:
conducting a chemical reaction in a solar driven chemical reactor
having multiple reactor tubes using concentrated solar energy to
drive the conversion of the chemical reactant, wherein an
endothermic chemical reaction conducted in the reactor tubes
includes one or more of the following: biomass gasification, steam
methane reforming, methane cracking, steam ethane or naphtha
cracking to produce ethylene and related olefins, or carbon dioxide
reduction or water splitting, using solar thermal energy coming
from a concentrated solar energy field; and starting an
entrained-flow of chemical reactants into the chemical reactor for
the endothermic chemical reaction when 1) the solar energy
concentrating field is aligned at an aperture of the solar thermal
receiver containing the solar driven chemical reactor, and 2) the
solar driven chemical reactor is at least a minimum operational
temperature of 800 degrees Celsius and preferably greater than 1000
degrees Celsius.
Description
RELATED APPLICATIONS
[0001] This application claims the benefit of both U.S. Provisional
Patent Application Ser. No. 61/248,282, filed Oct. 2, 2009 and
entitled "Various Methods and Apparatuses for Sun Driven
Processes," and U.S. Provisional Patent Application Ser. No.
61/185,492, titled "VARIOUS METHODS AND APPARATUSES FOR
SOLAR-THERMAL GASIFICATION OF BIOMASS TO PRODUCE SYNTHESIS GAS"
filed Jun. 9, 2009.
NOTICE OF COPYRIGHT
[0002] A portion of the disclosure of this patent document contains
material that is subject to copyright protection. The copyright
owner has no objection to the facsimile reproduction by anyone of
the software engine and its modules, as it appears in the Patent
and Trademark Office Patent file or records, but otherwise reserves
all copyright rights whatsoever.
FIELD OF THE INVENTION
[0003] Embodiments of the invention generally relate to systems,
methods, and apparatus for refining biomass and other materials.
More particularly, an aspect of an embodiment of the invention
relates to solar-driven systems, methods, and apparatus for
refining biomass and other materials.
BACKGROUND OF THE INVENTION
[0004] The substance/substances initially involved in a chemical
reaction are generally called reactants. Chemical reactions are
usually characterized by a chemical change in the reactants, which
then yields one or more products. Biomass gasification is an
endothermic process. Energy must be put into the endothermic
process to drive the chemical reaction forward. Typically, this is
performed by partially oxidizing (burning) the biomass itself.
Between 30% and 40% of the biomass must be consumed to drive the
process, and at the temperatures which the process is generally
limited to (for efficiency reasons), conversion is typically
limited, giving still lower yields. In contrast, the proposed
solar-driven biorefinery uses an external source of energy (solar)
to provide the energy required for reaction, so none of the biomass
need be consumed to achieve the conversion. This results in
significantly higher yields of gallons of gasoline per biomass ton
than previous technologies. As the energy source being used to
drive the conversion is renewable and carbon free. Also, chemical
reactors are generally engineered to operate at constant conditions
around the clock, rather than on a cyclic basis.
SUMMARY OF THE INVENTION
[0005] A method, apparatus, and system for a solar-driven chemical
plant that manages variations in solar energy are disclosed. Some
embodiments include a solar thermal receiver to aligned absorb
concentrated solar energy from one or more solar energy
concentrating fields including an array of heliostats, solar
concentrating dishes, and any combination of the two. A solar
driven chemical reactor may be at least partially contained within
the solar thermal receiver. Some embodiments include an entrained
gas biomass feed system that uses an entrainment carrier gas and
supplies a variety of biomass sources fed as particles into the
solar driven chemical reactor.
[0006] Additionally, some embodiments include a control system. The
control system may be configured to balance the gasification
reaction of biomass particles with the available concentrated solar
energy and additional variable parameters of a fixed range of
particle size, temperature of the chemical reactor, and residence
time of the particles in a reaction zone in the chemical reactor.
This can allow for an overall biomass particle conversion remains
above a threshold set point of substantial tar destruction to less
than 50 mg/Nm 3 and complete gasification of greater than 90
percent of the carbon content of the particles into reaction
products that include hydrogen and carbon monoxide gas.
[0007] A feedforward portion and a feedback portion of the control
system can be used to adapt for both long and short term
disturbances in available solar energy. Additionally, the
feedforward portion may anticipate cyclic changes in solar energy
due to at least a time of day, day of the calendar it is, and
periodic weather reports with a predictive model that adapts to the
anticipated cyclic changes. The feedback portion may measure actual
process parameters including the temperature of the chemical
reactor at an entrance and an exit.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The drawings refer to embodiments of the invention in
which:
[0009] FIG. 1 illustrates a block diagram of an embodiment of an
example process flow;
[0010] FIG. 2 illustrates a diagram of an embodiment of an example
multiple tube reactor;
[0011] FIG. 3 illustrates a diagram of an embodiment of an example
solar tower with receivers and solar energy concentrating
fields;
[0012] FIG. 4 illustrates a graph of an embodiment of particle size
distribution of some example biomass types;
[0013] FIG. 5 illustrates a diagram of an embodiment of a solar
thermal receiver with gasifier tubes;
[0014] FIGS. 6a and 6b illustrate block diagrams of embodiments of
the entrained-flow biomass feed system;
[0015] FIG. 7 illustrates a diagram of an embodiment of a
solar-driven chemical plant; and
[0016] FIG. 8 illustrates a flow diagram of an embodiment of the
system.
[0017] While the invention is subject to various modifications and
alternative forms, specific embodiments thereof have been shown by
way of example in the drawings and will herein be described in
detail. The invention should be understood to not be limited to the
particular forms disclosed, but on the contrary, the intention is
to cover all modifications, equivalents, and alternatives falling
within the spirit and scope of the invention.
DETAILED DISCUSSION
[0018] In the following description, numerous specific details are
set forth, such as examples of specific data signals, named
components, connections, number of reactor tubes, etc., in order to
provide a thorough understanding of the present invention. It will
be apparent, however, to one of ordinary skill in the art that the
present invention may be practiced without these specific details.
In other instances, well known components or methods have not been
described in detail but rather in a block diagram in order to avoid
unnecessarily obscuring the present invention. Further specific
numeric references such as first reactor tube, may be made.
However, the specific numeric reference should not be interpreted
as a literal sequential order but rather interpreted that the first
reactor tube is different than a second reactor tube. Thus, the
specific details set forth are merely exemplary and features in one
embodiment may be used in another embodiment. The specific details
may be varied from and still be contemplated to be within the
spirit and scope of the present invention. The term coupled is
defined as meaning connected either directly to the component or
indirectly to the component through another component.
[0019] In general, a method, apparatus, and system are described
for a solar-driven chemical plant that manages variations in solar
energy. An embodiment may include the solar thermal receiver, a
solar driven chemical reactor at least partially contained within
the solar thermal receiver, an entrained gas biomass feed system,
and other components. The entrained gas biomass feed system may use
an entrainment carrier gas to supply a variety of biomass sources
fed as particles into the solar driven chemical reactor. Some
embodiments include a control system that may be configured to
balance the gasification reaction of biomass particles with the
available concentrated solar energy and additional variable
parameters of a fixed range of particle size, temperature of the
chemical reactor, and residence time of the particles in a reaction
zone in the chemical reactor.
[0020] The control system may also send a feed demand signal to the
feed system. This can control a feed rate of the particles of
biomass in the solar driven chemical reactor by changing a gas
pressure and/or volumetric flow rate of the entrainment carrier
gas. In some embodiments, control the feed rate may be done in
combination with a metering device that controls a weight of
biomass particles from a lock hopper to the feed lines that feed
the chemical reactor.
[0021] The feedforward portion and a feedback portion of the
control system in cooperation with designing in enough surface
area, thermal mass, and heat capacity in the multiple tubes and
receiver cavity is used to ensure that temperature of the reactor
cavity remains in the operational temperature range of below 1600
degrees C. and above 800 degrees C. This range may be maintained
during potentially rapidly changing daily weather conditions.
Additionally, a feed forward model may predict an available solar
energy over each time period in a given day as well as each day
throughout the year. The feedback portion may receive dynamic
feedback from the temperature and/or light sensors. These may be
combined to maintain both the quality and output of resultant
syngas at above the threshold set point of substantial tar
destruction to less than 50 mg/m 3 and complete gasification of
greater than 90 percent of the carbon content of the biomass
particles into the reaction products.
[0022] FIG. 1 illustrates a block diagram of an example process
flow. Some embodiments encompass a solar-driven-biomass
gasification to liquid fuel/electrical process. The process might
also include generation, chemical processing, or bio-char, for
solar generated syngas derivative product or other similar
technical process. In a specific example implementation the process
described is a solar-driven-biomass gasification to `green` liquid
fuel process. In an embodiment, this process includes one or more
of the following process steps.
[0023] Biomass grinding or densification, transport and offload 100
may be part of the overall process. Bales of the biomass can be
compressed and densified by a compactor to facilitate transport to
on-site via the densification achieved by the double compression.
The bales are sized to dimensions that may, for example, fit within
a standard box car size or fit within standard compactor size. The
entrained-flow biomass feed system can be preceded by a grinding
system equipped with mechanical cutting device and a particle
classifier, such as a perforated screen or a cyclone, to control
the size of the particles that are. The grinding system that has a
mechanical cutting device such as a screw and set of filters with
micron sized holes/screen diameter sized holes to control particle
size. The mechanical screw and set of filters cooperate to grind
and pulverize the stock biomass to particles to the micron sized
holes of the filters, and the particles of biomass are then fed
into and gasified in the solar-driven chemical reactor. The biomass
may be in an embodiment non-food stock biomass. In other cases,
food stock biomass or a combination of the two might also be
processed.
[0024] The biomass may be stored 102. As needed, the biomass might
be feed 104 into an example system or apparatus of the instant
application. For example, after grinding and pulverizing the
biomass to particles, the particles of biomass can be fed into and
gasified in the solar-driven chemical reactor. Two or more feed
line supply the particles of biomass having an average smallest
dimension size between 50 microns (um) and 2000 um to the chemical
reactor. An entrained gas biomass feed system uses an entrainment
carrier gas to move a variety of biomass sources fed as particles
into the solar driven chemical reactor.
[0025] A solar receiver and gasifier 106 may be used to break down
the biomass. An example biomass gasifier design and operation can
include a solar chemical reactor and solar receiver to generate
components of syngas. The feedforward portion and the feedback
portion of the control system adapt the operation of the reactor to
both long and short term disturbances in available solar energy.
Various solar concentrator field designs and operations to drive
the biomass gasifier might be used. Some example systems may
include a solar concentrator, focused mirror array, etc. to drive
biomass gasifier 110.
[0026] Quenching, gas clean up, and ash removal from biomass
gasifier 108 may be provided for. Some gasses may be a waste
product, while other gasses can be compressed 114 prior to storage
118 or e.g., methanol synthesis 116. Methanol may then be stored
120 for later methanol to gasoline conversion 122.
[0027] An on-site fuel synthesis reactor that is geographically
located on the same site as the chemical reactor and integrated to
receive the hydrogen and carbon monoxide products from the
gasification reaction can be used in some embodiments.
Additionally, the on-site fuel synthesis reactor has an input to
receive the hydrogen and carbon monoxide products and use them in a
hydrocarbon fuel synthesis process to create a liquid hydrocarbon
fuel. The on-site fuel synthesis reactor may be connected to the
rest of the plant facility by a pipeline that is generally less
than 15 miles in distance. The on-site fuel synthesis reactor may
supply various feedback parameters and other request to the control
system. For example, the on-site fuel synthesis reactor can request
the control system to alter the H2 to CO ratio of the syngas coming
out of the quenching and gas clean up portion of the plant and the
control system will do so.
[0028] In various embodiments, synthesis gas may be fed to another
technical application. Examples include a syngas to other chemical
conversion process. The other chemical or chemicals produced can
include liquefied fuels such as transportation liquefied fuels. In
an example hydrocarbon based fuel, methanol 116 may be formed from
syngas. The methanol may be further converted to gasoline or other
fuels 122 and various products may be separated out from the
gasoline 124 or syngas. These products, e.g., gasoline, may then be
stored for later use as an energy source.
[0029] FIG. 2 illustrates a diagram of an example multiple tube
chemical reactor that may be used in a solar driven system. The
chemical reactor has multiple reactor tubes 202, 204, 206, 208. A
separate entrainment line may be used for each of the gasifier
reactor tubes 202, 204, 206, 208 in the chemical reactor 200. This
may allow for independent temperature control and balancing of
amount of particles of biomass flowing in each of the reactor tubes
202, 204, 206, 208 in the solar driven chemical reactor 200. The
particles of biomass feed can be distributed to the reactor tubes
202, 204, 206, 208 by a lock hopper rotary feed system, such as a
Rotofeed.RTM. lock hopper rotary feed system. Such a system can
allow for balanced feeding to individual reactor tubes 202, 204,
206, 208 and feed rate of the particles is controlled by a weight
measuring metering device such as load cells.
[0030] The biomass gasifier reactor and receiver control system may
manage variations in solar energy by passing signal between itself
and a solar energy concentrating field. Focused concentrated solar
energy on the solar thermal receiver 200 may come from one or more
solar energy concentrating fields including 1) an array of
heliostats, 2) solar concentrating dishes, and 3) any combination
of the two.
[0031] The solar driven chemical reactor can be contained within
the solar thermal receiver 200. The inner walls of the solar
thermal receiver 200 and the chemical reactor may be made from
materials selected to transfer energy by primarily heat radiation,
along with convection, and conduction to the reacting biomass
particles to drive the endothermic gasification reaction of the
particles of biomass flowing through the chemical reactor.
[0032] Note, a chemical reactor is the container in which a
chemical reaction occurs. Also, the chemical reactor may be a
single reactor tube, or a set of reactor tubes. Thus, the chemical
reactor may be a single reactor with multiple reactor tubes or
multiple reactors each being a single reactor tube, or some other
similar combination. Further, different chemical reactions may take
place in different reactor tubes of the solar-driven chemical
reactor. For example, Steam Methane Reforming may occur in a first
set of reactor tubes and biomass gasification may occur in another
set of reactor tubes making up the chemical reactor, which is at
least partially contained in the solar thermal receiver. Likewise,
different chemical reactions may take place in the same reactor
tubes of the solar-driven chemical reactor at the same time. Also,
the control system may control the chemical reactions occurring
within the reactor tubes via a number of mechanisms as described
herein. For example, the flow rate of the chemical reactants, such
as biomass particles and carrier gas, into and through the reactor
tubes is controlled, along with a concentration of each reactant
flowing through the reactor tube. The control system may control
each reactor tube individually, or in sets/groups of for example
clusters of eighteen tubes, or all of the tubes in their entirety.
The shape, orientation, and other features of the reactor tubes may
vary as described herein. Note, for contrast purposes, more than
one chemical reactor may be located on a common tower such as in
FIG. 3. The example shows a first chemical reactor, a second
chemical reactor, and a third chemical reactor contained at least
partially within its own associated solar thermal receiver. The
first, second, and third chemical reactors located on the same
tower may not share a common control system or common solar thermal
receiver, and thus, are truly each distinct chemical reactors.
However, they all may be fed from some common feed vessels/lock
hoppers and/or may share downstream quenching and gas clean up
system components.
[0033] In the multiple reactor tubes of the chemical reactor a
chemical reaction driven by radiant heat occurs. The chemical
reaction includes one or more of biomass gasification, steam
methane reforming, methane cracking, steam methane cracking to
produce ethylene, metals refining, and CO2 or H2O splitting to be
conducted in this chemical reactor using solar thermal energy from
the absorbed concentrated solar energy. A first set of tubes may
have steam methane reforming reaction occurring while a second set
of tubes has a biomass gasification reaction occurring.
[0034] The control system may be configured to balance the
gasification reaction of the biomass particles with the available
concentrated solar energy and additional variable parameters of a
fixed range of particle size, temperature of the chemical reactor,
and residence time of the particles in a reaction zone in the
chemical reactor. The control system hardware may be one or more of
a Programmable Logic Controller, via different data communication
protocols using Personal Computer, Macintosh, CNC, neural nets,
analog devices, with accompanying software applications and
algorithms scripted to perform various functions, or various
combinations of these systems.
[0035] One or more detectors indicate an amount of solar energy
available in different areas of the chemical reactor to guide the
control system in balancing an amount of the biomass particles
flowing in each of the reactor tubes.
[0036] In various embodiments, the control system can use both
feedforward (based on anticipated changes) and feedback (based on
actual measured changes) elements to control the balancing of the
gasification reaction occurring to result in negligible tar
formation in resultant syngas products and waste products. Control
strategies discussed herein have been developed to manage a
variation in solar energy due to changes in solar energy and a
cyclic operating state. Some embodiments include two or more
sensors including temperature sensors at the entrance and exit of
the chemical reactor and one or more light meters to provide
information to the feedback portion of the computer control. This
information indicates a feedback portion of the amount of solar
energy available indicated to the control system. The feed forward
system indicates an expected amount of solar energy available
indicated to the control system in the long and short term.
[0037] The control system can use the complex feedforward/feedback
model-predictive scheme to ensure that temperature of the reactor
cavity remains in the required range. The feedforward components
use meteorological measurements, geographical factors, and time of
day/day of year to predict the rate of change of available solar
energy and make process adjustments accordingly. Additionally, the
feedback component of the control system checks these predictions
against real time data to make appropriate corrections balanced by
not overcorrecting or under correcting for the instantaneous
changes in solar energy conditions. This control approach gives
robust system operation with a highly transient system input:
Sunlight.
[0038] In some embodiments, a feed demand signal from the control
system can be used to control the feed rate of particles of biomass
in the solar driven chemical reactor. This control can be performed
using a feedforward/feedback model-predictive scheme. The scheme is
aided by knowing an amount surface area, thermal mass, and heat
capacity in the multiple tubes and receiver cavity to ensure that
temperature of the reactor cavity remains in the operational
temperature range of below 1600 degrees C. and above 800 degrees C.
These temperatures might be maintained during rapidly changing
daily weather conditions. In some examples, the feed forward model
can predict a maximum, minimum, and average available solar energy
over each time period in a given day as well as each day throughout
the year.
[0039] A feedforward portion and a feedback portion of the control
system may be used to adapt for both long and short term
disturbances in available solar energy. For example, the
feedforward portion may anticipate cyclic changes in solar energy
due to at least a time of day, day of the calendar it is, and
periodic weather reports, such as daily or hourly weather reports.
The anticipation may be generated with a predictive model that
adapts to the anticipated cyclic changes. Additionally, the system
may compensate for missing data, such as missing weather
reports.
[0040] The feed-forward portion utilizes a histogram of events
affecting an amount of available solar energy categorized into at
least three general time durations. Events may further be
categorized as short events of 1 to 5 hours, often caused by
passing clouds; medium events of 5-14 hours, often caused by
diurnal effects (for our mid latitudes), long term events of 14
hours or more, generally caused by more major weather events. The
time of day, the day of the calendar and the daily weather report
may also be considered with respect to feed-forward
implementations. Additionally, in some embodiments, diurnal effects
may be considered by the feed-forward implementation. Diurnal
effects can relate to or occur within a 24-hour period each day and
including the predictable sunrise and sunset for daytime hours in a
daily period.
[0041] The feedback portion measures actual process parameters
including 1) various temperature parameters about the reactor
including the operating temperature at an entrance and an exit of
the chemical reactor, 2) the amount of concentrated light focused
at or received at the windows and/or open apertures, 3) chemical
composition of products coming out of the reactor and other similar
parameters, and then supplies these measurements to the control
system in the balancing of the gasification reaction of biomass
particles. The feedback portion of the control system may receive
the dynamic feedback from the sensors and combine this data in
order to maintain both the quality and output of resultant syngas
at above a threshold set point of substantial tar destruction to
less than 50 mg/m 3 and complete gasification of greater than 90
percent of the carbon content of the biomass particles into the
reaction products. Note, the temperature sensors in the receiver
may equally correlate temperature of various locations within the
reactor. Both temperature sensors in the receiver and the reactor
may be used as an indication of actual reaction temperature.
[0042] Additional parameters are known by the control system such
as enough surface area and thermal mass of the cavity and reactor
tubes is built into the multiple tubes and receiver cavity in
relation to the feed rate of biomass particles, to act as a
ballast, averaging out very short term small fluctuations (second
to second) in the available solar energy to have a very low ramp-up
and ramp-down of temperature of the reactor due to these
instantaneous changes in available solar energy. This can allow the
ramp-up and ramp-down of the feed rate of biomass particles to be
gradual as well.
[0043] One factor determinant in energy delivered by radiation to
the reacting particles, extent of reaction, and extent of tar
mitigation is reaction temperature. The receiver cavity temperature
may be a controllable parameter. Because the heliostat field has a
much longer response time (approximately 1-5 minutes) than does the
solar energy source (can vary within 30 seconds), the reaction
temperature may be controlled by modulating the biomass flow rate
through the reactor tubes. If reaction temperature starts to drop,
feed rate is decreased, reducing the reaction sink and allowing the
temperature to recover. The opposite is performed for
over-temperature. The thermal mass of the cavity and reactor tubes
acts as a ballast, averaging out very short term small fluctuations
(second to second) in the available solar energy. Flow rate
fluctuations in the syngas production rate occur as well. In the
case of slight underfeeding, product composition will not change,
but overfeeding can lead to a drop in temperature that can allow
tars to pass out of the reactor undestroyed.
[0044] A composition analyzer at the exit of the system will sense
changes in methane or tar composition. Upon readings of
compositions that are too high, the control system can divert the
products to a flare to avoid damage to the compressors and
catalytic systems in the methanol synthesis plant. The composition
analyzer at the exit of the reactor system may be used to sense
changes in hydrogen, carbon monoxide, methane and tar composition
of the syngas. The composition analyzer provides a dynamic signal
to the feedback portion of the control system. Upon readings of
methane and tar composition of the syngas that are too high above a
threshold, the control system sends a signal to divert the reactant
products of the gasification reaction to a recycling line back into
the entrance to the chemical reactor to avoid damage to
compressors, catalytic systems, and other components in the
methanol synthesis portion of the on-site fuel synthesis reactor.
The compressor to the syngas buffer tank may be designated to
follow flow rate fluctuations in the syngas production rate as
well.
[0045] The control system may send a feed demand signal to the feed
system to control a feed rate of the particles of biomass in the
solar driven chemical reactor by changing a gas pressure and/or
volumetric flow rate of the entrainment carrier gas in combination
with a metering device controlling a weight of biomass particles
from a lock hopper to the feed lines that feed the chemical
reactor. The control system may send a feed demand signal to the
feed system to control a feed rate to reactor tubes by isolating
that tube or set of tubes from receiving biomass. Thus, tubes
individually or in sets of tube may be turned on to have more
biomass flowing into the solar driven chemical reactor and turned
off/isolated to have less biomass particles flowing into the
chemical reactor.
[0046] Control of the multiple reactor tubes may be split into two
or more groups of tube subsets, where the control system balances
the amount of biomass particles flowing into each of the reactor
tubes to an amount of solar energy available by 1) controlling a
rotational rate of a screw of a lock hopper feeding the biomass
where all the tubes in the tube subset have their feed rate
simultaneously turned up or turned down, 2) varying an amount of
the reactor tube-subsets participating in the gasification reaction
by turning on or turning off a flow of particles of biomass from
the lock hopper to the reactor tubes making up a tube subset, or 3)
a combination of both.
[0047] In an embodiment, a 2-phase pinch valve system may be on
each feed line to each reactor tube. The control system balances
the amount of biomass particles flowing in each of the reactor
tubes to the amount of solar energy available by sending a dynamic
feedback control signal to the 2-phase pinch valve system to
control an amount of compression of a flexible pipe section of the
feed line that the biomass particles are flowing through to control
flow in the individual reactor tubes. The detectors indicate the
amount of solar energy available to guide the control system.
[0048] Such a system can be used to control flow in the individual
reactor tubes by controlling a rotational rate of a screw/auger of
a lock hopper feeding the biomass. Additionally, an amount of
compression of a pinch valve configuration may be applied to a
conduit such as a hose, tube, pipe, or other vessel capable of
conveying materials section of each individual feed line that the
biomass particles are flowing through to provide some control of
flow, for example.
[0049] The solar-driven chemical plant can include a chemical
reactor that has multiple reactor tubes 202, 204, 206, 208 in which
the biomass particles flow in. Two or more reactor tubes in the
chemical reactor tubes might be used. The example illustrated
includes five reactor tubes. One or more feed lines supply to the
reactor tubes the particles of biomass in the fixed range of
particle size controlled to an average smallest dimension size
between 50 microns (um) and 2000 um, with a general range of
between 200 micrometer and 1000 micrometer. Additionally, the
control system maintains the temperature at an exit from the tubes
202, 204, 206, 208 of the chemical reactor at a steady state
temperature exceeding 1000 degrees C., above transitory minimum
temperature of 800 degrees C. and below peak temperatures of 1600
degrees C. Further, the control system monitors the residence time
of the particles of biomass in the reaction zone in the chemical
reactor, which is between a range of 0.01 and 5 seconds.
[0050] A separate feed line can be used to feed biomass particles
for each of the reactor tubes 202, 204, 206, 208 in the chemical
reactor 200, which can allow independent temperature control and
balancing of the amount of particles of biomass flowing in each of
the reactor tubes in the multiple tube solar driven chemical
reactor.
[0051] The receiver cavity, the multiple reactor tubes, and the one
or more open apertures or windows are shaped and sized to
facilitate greater than 75% average aperture/window incident power
to be converted into chemical/sensible energy at peak incident
power. Thus, greater than 75% the amount of energy entering the
receiver 200 as solar energy ends up as chemical or sensible
enthalpy leaving the reactor tubes. Also, a conversion of carbon in
the particles of biomass to CO (and in some cases, CH4) above 85%
yield/ton of the biomass occurs from the gasification reaction.
[0052] The size and shape of one or more apertures in the receiver
and a range of operating temperatures of the cavity of the receiver
enclosing the chemical reactor can be set to make radiation losses
directly calculable. An insulation layer around the cavity may be
set thick enough to control conduction losses to, e.g., less than
2% of the peak solar input. Once the chemical reactor is heated up
to operational temperatures, due to the conduction losses to less
than 2% and the radiation losses being directly calculable, then
the receiver cavity temperature is a controlled parameter. The
control system then primarily controls by modulating a flow rate of
biomass particles through the reactor tubes balanced against the
predicted feed-forward available amount of solar energy and the
dynamically determined feedback amount of available solar
energy.
[0053] The control system may supply a control signal to the feed
system, the solar energy concentrating fields, the on-site fuel
synthesis reactor and other plant systems. For example the control
system signal may direct and receive feedback from 1) the solar
concentrating field to alter alignment and an amount of
concentrated solar energy supplied, 2) the feed system to alter an
amount and or concentration of biomass flowing in the reactor
tubes, and/or which sets of reactor tubes are allowing flow of
chemical reactants, and thus, participating in the solar driven
chemical reaction, 3) various sensors or models for weather events
indicating an amount of solar energy available etc. and 4) other
similar plant processes discussed herein. All of these factors may
be taken into account by a control algorithm in the control system
in sending out the control signals to the feed system, the solar
energy concentrating fields, etc.
[0054] In some embodiments, the receiver cavity, the multiple
reactor tubes, and the one or more apertures or windows are shaped
and sized to map an amount of solar flux distribution to the
reactor tube size and geometric position to allow essentially a
same rate of biomass gasification for a set biomass particle size
range everywhere in the reactor, and thus, avoiding locally
extremely high temperatures (>1500.degree. C.) or extremely low
temperatures (<600 C).
[0055] A chemical reaction is conducted in a solar driven chemical
reactor having multiple reactor tubes using concentrated solar
energy to drive the conversion of the chemical reactant. The
endothermic chemical reaction conducted in the reactor tubes
includes one or more of the following: biomass gasification, steam
methane reforming, methane cracking, steam ethane or naphtha
cracking to produce ethylene and related olefins, or carbon dioxide
reduction or water splitting, using solar thermal energy coming
from a concentrated solar energy field. An entrained-flow of
chemical reactants into the chemical reactor for the above
reactions starts when 1) the solar energy concentrating field is
aligned at the aperture of the solar thermal receiver containing
the solar driven chemical reactor, and 2) the solar driven chemical
reactor is at least a minimum operational temperature of 800
degrees Celsius and preferably greater than 1000 degrees Celsius.
During start up of the integrated chemical plant, temperature of
the chemical reactor is raised to get up to an operational
temperature of at least 800 degrees C. so that the effluent
reactant products from the chemical reactor possesses a proper gas
composition and quality for downstream chemical processing such as
methanol synthesis.
[0056] The control system may utilize different models and/or
controls schemes that may be automatically or manually selected
depending on the system and variable state. For example, insolation
perturbation may be categorized into 3 types: 1) short events, e.g.
0-5 hours, often caused by passing clouds, 2) medium events, e.g.
5-14 hours, often caused by diurnal effects, and 3) long-term
events (e.g. 14 hours or more) generally caused by major weather
systems and other variables such as, but not limited to, time of
day, day of the year, daily weather reports, solar field condition,
and biomass type and condition, may be considered by the control
system when selecting between and executing different models and/or
control schemes. The models and/or control schemes may be fixed,
adaptive, replaced, or augmented from time to time.
[0057] FIG. 3 illustrates a diagram of an example solar tower 300
with receivers 302 and solar energy concentrating field 304. A
solar tower 300 may be used in the solar-driven chemical plant with
the entrained-flow biomass feed system. The feed system can be
feedstock flexible via, for example, particle size control of the
biomass.
[0058] Multiple solar thermal receivers 302 may be on a common
tower 300. Each receiver 302 contains a chemical reactor 306. A
chemical reactor 306 in each receiver 302 receives concentrated
solar thermal energy from one or more solar energy concentrating
fields 304 including 1) an array of heliostats, 2) solar
concentrating dishes, and 3) any combination of the two. The
chemical reactor 306 can be, for example, a multiple reactor tube,
downdraft, solar driven, chemical reactor 306, which receives
concentrated solar thermal energy from the array of heliostats 306.
The solar-driven chemical plant may also include a biomass feed
system that has the feed lines to each of the reactor tubes in a
multiple tube chemical reactor 306. Biomass may be fed to the solar
reactor 306 in an operation including three parts: biomass
transport and preparation for feeding to the solar tower reactor
300, biomass transport to the top of the, e.g., 500+ foot tower,
and distribution into the specific downdraft tubes of the reactor.
The distribution may be performed via multiple stages.
[0059] The tower 300 supports the elevated solar thermal receiver
302 and solar driven chemical reactor 306. The tower 300 is tall
enough, such as at least 150 meters, in height to give an optimized
angle of elevation for the solar energy concentrating fields
304.
[0060] The solar-driven chemical reactor system can include a
non-uniform heliostat field has >25,000 m 2 of reflecting
surface, >50,000 m 2 of reflecting surface, or >100,000 m 2
of reflecting surface, that cooperates with the solar thermal
receiver to have an ability to control an amount of solar energy
flux across the apertures or windows. Reflectors with other total
reflective surfaces areas may also be used.
[0061] The reflecting surface cooperates with the solar thermal
receiver to have an ability to control an amount of solar energy
flux across the apertures or windows that is applied to reactor
tubes and cavity walls to allow enough energy from a radiant energy
to raise the heat. This increase in the heat may initiate and
sustain a sufficiently high temperature so that complete
gasification occurs of greater than 90 percent of the carbon
content of the biomass particles into reactant products. The
reactant products can include hydrogen and carbon monoxide gas in
the very short residence time between the range of 0.01 and 5
seconds. The size and a shape of the one or more apertures or
windows can determined by the heliostat field trying to focus into
the apertures or windows a total amount of light in sun
concentrations that is needed for the short residence times
balanced against an efficiency of a solar energy being concentrated
from the non-uniform heliostat field. The control system configured
to balance the chemical reaction with the available concentrated
solar energy.
[0062] In some embodiments, each heliostat has a mirror and the
array of mirrors in the heliostat field are configured to obtain
both 1) dense packing in at least the first third of the part of
the field near the receiver and 2) optimal small shading. The first
third of the part of the field has the highest proportion of energy
off of each of the mirrors. The concentrated solar energy from this
dense packed portion of heliostats intercepts the one or more
apertures or windows of the receiver. The remainder of the field is
aimed at the one or more apertures or windows of the receiver but
proportionately provide less solar energy.
[0063] Optimal small shading and minimal blocking also occurs for
the mirrors in the heliostat field due to 1) the angle of elevation
of the heliostat field to the solar thermal receiver on the tower,
in combination with 2) the staggered heights and 3) the spacing of
the rows of the non-uniform heliostat field. The heliostat field
can receive control signals from the control system to control an
alignment of the field relative to the solar receiver. The
heliostat field may supply signals such as an amount of available
solar energy to the control system.
[0064] Some embodiments can include one or more actuators on the
heliostats and/or on the receiver. The one or more apertures can be
articulated moveable apertures that are capable of varying location
on the solar thermal receiver, e.g., on top of the tower 300. These
movements may depend on the time of day or season of the year and
be based on the actuators moving the apertures.
[0065] A model of solar energy flux can be used to map the
apertures with respect to the solar power delivered to the aperture
changes over time under similar natural solar conditions in order
to assist the control system in guiding the actuators in moving the
apertures and/or heliostats.
[0066] One or more structures with high temperature storage
material that absorb the concentrated solar energy contained within
the receiver chamber may be used. The structures may be used as
radiant heat masses to keep the chemical reactor hot during long
periods of off sun, during cyclic up and down times in the plant,
as well as keep radiant temperature in the reactor more stable/less
transient during normal operation. One or more of these radiant
heat masses can be positioned in the cavity in areas of extremely
high concentrated solar energy compared to other areas within the
cavity to absorb some of the concentrated solar energy in that area
to allow the reactor tubes to all use the same material.
[0067] In some embodiments, a material making up the reactor tubes
can possess high emissivity such as 0.7 emissivity coefficient or
better, high thermal conductivity such as 30 watts per meter-Kelvin
or better, at least moderate heat capacity of 8 joules per
mole-degree Kelvin or better. The material can also be resistant to
the oxidizing air environment in the cavity and the reducing
environment of the biomass gasification reaction inside the tubes
in order to support operating temperatures within the tubes in the
tar-cracking regime between 1000-1300.degree. C. This operating
temperature eliminates any need for tar cracking equipment
downstream of the chemical reactor. In addition, operation at the
high operating temperature in the reactor tubes improves heat
transfer, eliminates methane from the exit gases, and decreases
required residence time of the biomass particles to achieve
complete gasification, which in turn decreases a physical size of
the chemical reactor.
[0068] One or more apertures 1) open to the atmosphere or 2)
covered by windows can be part of a receiver outer shell that at
least partially encloses the multiple reactor tubes 202, 204, 206,
208. Additionally, a material making up the receiver inner wall
absorbs, including a black body, or the material highly reflects,
including refractory alumina plate, the concentrated solar energy.
This causes the radiant heat and then generally radiatively conveys
that heat like an oven to the biomass particles in the reactor
tubes. The inner wall may operate at high (>1200.degree. C.)
wall temperatures and the insulation thickness is designed so as to
limit losses through conductive heat loss to less than 2% of the
energy incident at peak solar input on the receiver apertures or
windows.
[0069] The solar thermal receiver may further include a thick layer
of insulation that limits heat losses by conduction from a cavity
of the receiver and a moveable insulative door on the receiver
aperture limits heat losses by radiation from the cavity during
periods of inclement weather or during nighttime, so that the
temperature in the cavity is decreased by less than 400.degree. C.
in a 12 hour period when no concentrated solar energy is directed
at the cavity aperture. Maintaining an elevated temperature in the
receiver reduces the amount of time required to heat the receiver
following a down period and the thermal shock and stresses imparted
to the receiver and reactor materials of construction. In some
embodiments, the receiver may include a pump to pump molten salts
through tubes in the receiver walls for use in electrical power
generation.
[0070] In some embodiments, an aperture design, orientation, and
cavity working fluid (buoyancy) may be set to control convective
losses The cavity may at least partially enclosing the multiple
reactor tubes and may acts like an oven, spreading heat flux around
through radiation. The oven effect of the cavity, along with the
particles, may tend to average energy amongst themselves at their
design volumetric loadings and combine to give a fairly uniform
temperature profile and subsequent fairly uniform reaction profile
of the biomass particles.
[0071] The control system is configured to take all of the above
into consideration when balancing the chemical reaction needs with
the available concentrated solar energy.
[0072] FIG. 4 illustrates a graph of cumulative particle size
distribution. The graph illustrates the weight percentage below Y %
for a given screen size in microns. Example materials are
illustrated including knife-chopped rice straw and miscanthus
stems. The smaller the size of the particle of the various types of
biomass, the less difference in the way the feed system and reactor
view particles from different types of biomass. The average size of
ground particles may be correlated to filter particle size used in
standard filter ranges.
[0073] As the gasification is performed through indirect heating,
the cavity and tube walls must be able to efficiently conduct solar
energy through themselves and radiate to the reacting particles.
Residence times greater than 2 seconds will be more than sufficient
for the biomass to be gasified at temperatures between 500.degree.
C. and 1000.degree. C. The key limiting factor in receiver design
is heat transfer from the indirectly heated cavity wall and the
reacting particulates.
[0074] In some embodiments, the carbonaceous biomass material
particles being fed from the entrained flow biomass feed system
undergo several distinct chemical processes of the gasification
reaction prior to exiting the reactor tubes. These processes
include at least the following three stages: A) pyrolysis of the
carbonaceous biomass particles into 1) carbonaceous char and 2)
volatile components vaporized into gas products; B) complete
gasification of the carbonaceous char including lignin fractions
into 1) gaseous products including carbon monoxide, hydrogen, and
tars as well as 2) greater than 99% pure carbonaceous ash; and C)
cracking of the tars including larger hydrocarbons and aromatic
compounds collectively known as tars. This gasification can occur
at greater than 1000 degrees C. to the produce the substantial tar
destruction to less than 50 mg/m 3 and complete gasification of
greater than 90 percent of the carbon content of the biomass
particles into reaction products including hydrogen and carbon
monoxide gas. The steps of complete gasification and cracking of
tars starts and finishes within the residence time of the biomass
particles in the reaction zone in the chemical reactor between the
range of 0.01 and 5 seconds.
[0075] As discussed above, in various embodiments complete
gasification of the carbonaceous char including lignin occurs.
Lignin is a complex chemical compound derived from biomass, and an
integral part of the secondary cell walls of plants. Lignin fills
the spaces in the cell wall between cellulose, hemicellulose, and
pectin components. Additionally, preheating of the biomass prior to
being fed into the reactor tubes may raise the temperature above
200 degrees C. beginning the pyrolysis process. Thus, at least the
last two steps may start and finish within the residence time
within the reactor tubes.
[0076] In an embodiment, 1) a material and 2) an indirect
gasification design of the heat radiation from the multiple reactor
tubes and walls of the receiver allows for feedstock flexibility in
the type of biomass making up the particles of biomass. This can
obviate a need for an exothermic/endothermic reaction balancing
because the heat radiation from the concentrated solar energy
absorbed or highly reflected by the walls and tubes primarily
drives the endothermic gasification reaction and the heat
radiation-based heat transfer balancing makes the endothermic
reaction gasification quite forgiving in terms of internal reaction
balance. Thus, at least two or more different types of biomass
materials might be used in the same reactor tube geometry. This may
obviate any need for a complete reengineering when a new type of
biomass feedstock is used. The two or more different types of
biomass materials that can be fed from the feed system,
individually or in combinational mixtures, are selected from the
group consisting of rice straw, rice hulls, corn stover, switch
grass, non-food wheat straw, miscanthus, orchard wastes, sorghum,
forestry thinning, forestry wastes, source separated green wastes
and other similar biomass sources. These sources might be used
interchangeable as long as a few parameters are controlled such as
the particle size of the biomass and temperature of the chemical
reactor. The complete gasification of the particles of miscanthus
may be equal to or greater than 94% when miscanthus is fed and the
complete gasification of the particles of rice straw is equal to or
greater than 98% when rice straw is fed from the feed system.
[0077] Different chemical reactants may be fed with the biomass,
such as methane, natural gas, steam, etc. The control system may be
configured to balance chemical reaction types, such as a biomass
gasification reaction, a stream reforming reaction, a dry reforming
reaction and various combinations of these reactions within the
solar driven chemical reactor, to an amount of concentrated solar
energy available directed at the solar thermal receiver in order to
keep the solar chemical reactor at a temperature at which the
chemical reactor operates high enough to maintain the generated
syngas within the desired molar ratio of H2 to CO ratio with being
substantially tar free and having less than 7% by volume CO in the
generated syngas.
[0078] The control system for the solar driven chemical reactor and
its multiple reactor tubes factors in many parameters in its
control algorithms for chemical reactor operation. The control
system controls balancing of mass in and energy needed to drive
various chemical reactions verses available concentrated solar
energy because each endothermic reaction consumes an amount of
available energy AND the algorithm controls concentration/amount of
each reactant product into the chemical reactor to control the
molarity and ratio of the reactants going into the reactions in
order to control the products coming out of the reactions, AND the
algorithm may control what chemical reactants are being supplied to
the reactor and thus what chemical reactions are occurring within
multiple reactor tubes.
[0079] The endothermic chemical reaction conducted in to the solar
driven chemical reactor includes one of the following: biomass
gasification, steam methane reforming, methane cracking, steam
ethane cracking to produce ethylene, metals refining, carbon
dioxide capture and other similar endothermic carbon-based chemical
reactions can be conducted in this reactor using solar thermal
energy.
[0080] Note, the control system and reactor tubes may be configured
to the produce hydrogen and carbon monoxide products from one or
more of the following reactants in the tubes 1) biomass particles
and steam, 1) biomass particles, methane and steam (SMR), or
methane and carbon black particles.
[0081] In some embodiments, a carrier gas supply line can supply
the entrainment gas as a pressurized dry steam. Natural gas may be
fed along with the biomass particles during a co-gasification of 1)
biomass in the presence of steam and 2) steam reforming of natural
gas, and the pressurized dry steam is generated from waste heat
recovered from either 1) methanol/Methanol-To-Gasoline (MTG) units
in the hydrocarbon fuel synthesis process or 2) the products from
the gasification reaction in the solar driven chemical reactor.
[0082] In some embodiments, a stoichiometric ratio of steam may be
injected along with the particles of biomass into the reactor tubes
during the gasification reaction to shift some of the product
carbon monoxide to additional hydrogen and carbon dioxide gas,
making the hydrogen to carbon monoxide ratio appropriate for
methanol synthesis by the onsite fuel synthesis reactor. In such an
embodiment, the inside walls of the reactor tubes may be are made
of corrosion resistant materials with a resistance to steam of
between a good to excellent rating.
[0083] FIG. 5 illustrates a diagram of a solar thermal receiver 500
with gasifier tubes 502. The solar-driven chemical plant can
include a solar driven chemical reactor 502, a solar thermal
receiver 500, or both. In some embodiments, solar thermal receiver
500 can enclose the multiple reaction tube downdraft chemical
reactor. Additionally, the feed system may feed biomass particles
into the multiple reaction tubes 502, in which the particles of
biomass may be gasified in the presence of steam at a temperature
exceeding 950 degrees C. from an exit of a gasification reaction
zone of the reactor tubes.
[0084] Some embodiments may include one or more apertures 1) open
to an atmosphere of the Earth or purge gas environment in the
cavity or 2) covered by more windows. The apertures and windows act
to pass the concentrated solar energy into the solar thermal
receiver to impinge on the multiple reactor tubes and cavity walls
of the receiver and transfer energy by solar radiation absorption
and heat radiation, convection, and conduction to the reacting
particles.
[0085] The length and diameter dimensions of a gasification
reaction zone of each of the reactor tubes, along with an
arrangement and an amount of the tubes are matched to an amount of
sun concentration from the heliostat field to give the fast
residence time of 0.01 second to 5 seconds, with the preferred
residence time of 2-3 seconds at the biomass gasification
temperatures.
[0086] FIGS. 6a and 6b illustrate block diagrams of embodiments of
the entrained-flow biomass feed system 600. Different types of feed
systems may be used in conjunction with a biomass into reactor, for
example, drop tube, total solid feed into the reactor, slurry fed
into the reactor, a moveable bed in the reactor, or combinations of
these schemes.
[0087] One or more feeding vessels in the biomass feed system
supply two or more reactor tubes in the solar-driven chemical
reactor. Each of the feeding vessels has one or more outlets
configured to supply a consistent volumetric amount of biomass
particles.
[0088] One example solar-driven chemical plant may include the
entrained-flow biomass feed system 600 that includes or otherwise
cooperates with a grinding system. The grinding process 603 and
feed process may be 1) processes separated in time and completed
independently of the other process or 2) a continuous process of
the where the grinding process 603 occurs and immediately feeds
biomass into the feed system and then into the chemical
reactor.
[0089] An objective of the feeding system is to feed as many
reactor tubes as possible with the fewest number of feeding vessels
such as lock-hopper systems.
[0090] The grinding system 603 has a mechanical cutting device used
to grind the biomass into primary particles, which are to be fed
into the solar driven chemical reactor. The grinding system
supplies primary particles that have an average smallest dimension
size between 200 microns (um) and 2000 um, with a general range of
between 500 um and 1000 um to a lock hopper system 604 with a
standard belt conveyer. The biomass particles are then fed across a
pressure boundary into a pressurized entrainment gas for feeding
into in the solar driven chemical reactor. The feeding vessel may
use an Auger/Screw feeder or an airlock-type rotational solids
feeding/rate metering device.
[0091] As illustrated in FIG. 6a, the entrainment-flow biomass feed
system 600 can include a pressurized lock hopper 604 that feeds the
biomass to a rotating screw conveyor 602 and a metering device and
then into an entrainment gas pipe at the lock hopper exit 606. A
flow splitter distributes the particles of biomass into multiple
entrainment gas lines to feed at least two or more of the multiple
reactor tubes making up the solar driven chemical reactor. The
entrainment gas for the pneumatic biomass feed system may be a
pressurized dry steam generated from waste heat recovered from
either 1) the methanol/Methanol-To-Gasoline (MTG) units in the
hydrocarbon fuel synthesis process or 2) the products from the
gasification reaction in the solar driven chemical reactor. The
entrainment gas may also be CO2, natural gas, an inert gas, steam
generated in any fashion, or other similar entrainment gas.
[0092] Additionally, an entrained-flow biomass feed system having
one or more feed lines to feed the biomass particles into the
multiple reactor tubes, in which a separate entrainment line and
metering device of the entrained-flow biomass feed system is used
for each of the gasifier reactor tubes in the chemical reactor.
This may allow for balancing of 1) amount of particles of biomass
flowing through the feed line to each reactor tube to 2) an amount
of solar energy available for that reactor tube in the multiple
tube solar driven chemical reactor. Feed rate of the biomass
particles can be controlled by a metering device and controlling a
rotational rate of a screw 602 at a base of the lock hopper 604,
which responds to a feed demand signal received from the control
system.
[0093] Thus, control of the rotational rate of the screw or auger
602 can move set amounts of biomass along the axis of rotation of
the auger 602. The auger 602 may be located at the base of the lock
hopper 604 and can be controlled by a control system to respond to
feed demand of the system. As discussed, the control system
controls the feed rate of particles of biomass in the solar driven
chemical reactor based on an amount of solar energy available
indicated by sensors including temperature sensors and/or light
meters.
[0094] In some embodiments, the shape and width of the outlet of
the feed line pipe carrying the biomass particles to its
corresponding reactor tube may be used to control a dispersion
pattern of biomass particles entering each reactor tube. Greater
than 90% conversion may occur because of both 1) the high operating
temperatures and 2) that the biomass particles are well separated
from one another in a flowing dense cloud of very fine biomass
particles. An amount of oxygen, air, or steam co-currently flowing
in the gasification of the biomass particles can be controlled to
cause a selectivity of carbon reactant from the biomass to become
CO rather than CO2 at better than a 10:1 selectivity to CO over
CO2.
[0095] FIG. 7 illustrates a diagram of a solar-driven chemical
plant 800. In such a system solar power from a concentrating field
802 may be provided through a window or aperture 804 to a solar
heated reactor chamber 806. A quencher 808 may be used to prevent
back reaction. As illustrated, biomass particles flow into the
system at 810 and syngas flows out. Additionally, a heat exchange
may occur between the biomass particles and the syngas.
[0096] In reactor 806 biomass particles can be reduced to syngas,
which in turn can be synthesized into liquid fuel in liquid fuel
synthesizer 808. Additionally, an example system may store
concentrated solar energy in chemical bonds by using the solar
energy to produce a liquid hydrocarbon fuel. Liquid hydrocarbon
fuel is generally easily storable and transportable. Examples of
liquid hydrocarbon fuel include, but are not limited to one or more
of jet fuel, DME, gasoline, diesel, methanol, and mixed alcohol,
synthetic natural gas production, and heating oil generation.
[0097] FIG. 8 illustrates a flow diagram. In step 900, biomass
grinding can occur. Equipment generally used for grinding biomass
includes impact mills (e.g. hammer mills), attrition mills, and
kinetic disintegration mills (e.g. flail mills). A hammer mill
system can be used to grind the bales (loaded by conveyer) into
primary particles. The re-ground particles have an average size
between 500 um and 1000 um, and are loaded into the lock hopper
system with a standard belt conveyer.
[0098] In step 902 biomass feeding occurs. In some embodiments,
high pressure feeding may be used. High pressure feeding of solids
of biomass with gasification at pressure may reduce capital cost
due to the ability to use smaller compressors in some such systems.
The lock hopper system can feed the reactor processes at pressure.
For example, the feeding system can entrain the biomass materials
in steam at high pressure, successfully disengage the particulates
in the cyclone system, and distribute flow appropriately to the
reactor tubes.
[0099] In step 904, gasification occurs. For example, in some
embodiments, concentrated solar thermal energy drives gasification
of the particles of the biomass to generate at least hydrogen and
carbon monoxide products from the gasification reaction.
[0100] In step 906 fuel synthesis occurs. An on-site fuel synthesis
reactor can receive the hydrogen and carbon monoxide products from
the gasification reaction and use the hydrogen and carbon monoxide
products in a hydrocarbon fuel synthesis process to create a liquid
hydrocarbon fuel.
[0101] Some embodiments of the solar-driven chemical plant include
a spray nozzle to supply water to the product gas exiting the
chemical reactor to shift some of the product carbon monoxide to
additional hydrogen and carbon dioxide gas in a water gas shift
reaction, making the hydrogen to carbon monoxide ratio appropriate
for methanol synthesis, such as a H2:CO ratio in the synthesis gas
within the range 2.0 to 2.7.
[0102] An insulation layer around the receiver can include
resistance heaters connected to the outer wall of the receiver to
assist with maintaining temperature in the 800-1600 degree C.
range. Waste heat from a quenching unit quenching the gasification
products heats high temperature storage material in hot beds in an
exit of the receiver, which is used with molten salts for use in
electrical power generation. The electrical power may be a source
of power for the resistance heaters. The control system can turn on
and off the resistance heaters as additional heat sources for
maintaining temperature as need be. The control system supplies a
control signal to 1) the feed system, 2) the solar energy
concentrating fields, 3) and the supplemental resistance heating
system 4) potentially to a recirculation system, and 5) other
systems. The lag times and response times of the: 1) solar energy
concentrating fields to alter alignment and an amount of
concentrated solar energy supplied, 2) feed system to alter an
amount of biomass flowing in the reactor tubes, 3) time for weather
events to alter an amount of solar energy available, such as 30
seconds for a cloud, are factors taken into account by a control
algorithm in the control system in sending out the control signals
to the feed system, the solar energy concentrating fields and the
supplemental resistance heating system.
[0103] The methods and apparatuses of the invention in some cases
may be implemented using computer software. If written in a
programming language conforming to a recognized standard, sequences
of instructions designed to implement the methods can be compiled
for execution on a variety of hardware platforms and for interface
to a variety of operating systems. It will be appreciated that a
variety of programming languages may be used to implement the
teachings of the invention as described herein. Furthermore, it is
common in the art to speak of software, in one form or another
(e.g., program, procedure, application, driver, etc.), as taking an
action or causing a result. Such expressions are merely a shorthand
way of saying that execution of the software by a computer causes
the processor of the computer to perform an action or produce a
result.
[0104] The control system may operate in a networked environment
using logical connections to one or more remote computers, such as
a remote computer. The remote computer may be a personal computer,
a hand-held device, a server, a router, a network PC, a peer device
or other common network node, and typically includes many or all of
the elements described above relative to the computer.
[0105] A machine-readable medium is understood to include any
mechanism for storing or transmitting information in a form
readable by a machine (e.g., a computer). For example, a
machine-readable medium includes read only memory (ROM); random
access memory (RAM); magnetic disk storage media; optical storage
media; flash memory devices, etc.
[0106] Some portions of the detailed descriptions above are
presented in terms of algorithms and symbolic representations of
operations on data bits within a computer memory. These algorithmic
descriptions and representations are the means used by those
skilled in the data processing arts to most effectively convey the
substance of their work to others skilled in the art. An algorithm
is here, and generally, conceived to be a self-consistent sequence
of steps leading to a desired result. The steps are those requiring
physical manipulations of physical quantities. Usually, though not
necessarily, these quantities take the form of electrical or
magnetic signals capable of being stored, transferred, combined,
compared, and otherwise manipulated. It has proven convenient at
times, principally for reasons of common usage, to refer to these
signals as bits, values, elements, symbols, characters, terms,
numbers, or the like. These routines, algorithms, etc. may be
written in a number of different programming languages. Also, an
algorithm may be implemented with lines of code in software,
configured logic gates in software, or a combination of both. The
portable application and its security mechanisms may be scripted in
any number of software program languages. Unless specifically
stated otherwise as apparent from the above discussions, it is
appreciated that throughout the description, discussions utilizing
terms such as "processing" or "computing" or "calculating" or
"determining" or "displaying" or the like, refer to the action and
processes of a computer system, or similar electronic computing
device, that manipulates and transforms data represented as
physical (electronic) quantities within the computer system's
registers and memories into other data similarly represented as
physical quantities within the computer system memories or
registers, or other such information storage, transmission or
display devices.
[0107] While some specific embodiments of the invention have been
shown the invention is not to be limited to these embodiments. The
invention is to be understood as not limited by the specific
embodiments described herein, but only by scope of the appended
claims.
* * * * *