U.S. patent application number 13/008883 was filed with the patent office on 2012-01-26 for simultaneous production of electrical power and potable water.
Invention is credited to John P. Gaus, Philip D. Leveson.
Application Number | 20120017591 13/008883 |
Document ID | / |
Family ID | 44212129 |
Filed Date | 2012-01-26 |
United States Patent
Application |
20120017591 |
Kind Code |
A1 |
Leveson; Philip D. ; et
al. |
January 26, 2012 |
SIMULTANEOUS PRODUCTION OF ELECTRICAL POWER AND POTABLE WATER
Abstract
Biomass or refuse-derived fuels (10) and seawater or other
non-potable water are used as an input to a combustor/evaporator
(15, 20). The resulting steam heats a working fluid in an Organic
Rankine Cycle (30, 50, 60, 75) process which drives a turbine (50)
to produce mechanical rotation. This rotation can be used to
directly drive a process or to generate electricity. The heating of
the working fluid cools the steam to produce purified water. The
evaporator provides a water purification process for both the
separation of dissolved components as well as providing for thermal
pasteurization/sterilization. Suitable water inputs are seawater,
brackish water and water with those waterborne diseases and
pathogens which can be killed through
pasteurization/sterilization.
Inventors: |
Leveson; Philip D.; (Sandy
Springs, GA) ; Gaus; John P.; (Watertown,
NY) |
Family ID: |
44212129 |
Appl. No.: |
13/008883 |
Filed: |
January 18, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61296142 |
Jan 19, 2010 |
|
|
|
Current U.S.
Class: |
60/645 ;
60/670 |
Current CPC
Class: |
Y02E 20/14 20130101;
F01K 25/10 20130101; F01K 17/04 20130101; F22B 1/1884 20130101;
F22B 9/12 20130101 |
Class at
Publication: |
60/645 ;
60/670 |
International
Class: |
F01K 13/00 20060101
F01K013/00; F01K 23/06 20060101 F01K023/06 |
Claims
1. A power generation and water purification apparatus, comprising:
a combustion chamber to burn a fuel to provide combustion products,
and having a fuel input port to receive said fuel; a boiling tank
having a water input port to receive water and a steam output port
to discharge steam; a plurality of heat exchange tubes, connected
in parallel, and functionally connected to said combustion chamber
to receive said combustion products, said tubes being at least
partially inside said boiling tank and to transfer heat from said
combustion products to said water in said boiling tank to produce
said steam; an exhaust conduit, functionally connected to the
plurality of heat exchange tubes, to receive and discharge
combustion products which have flowed through the plurality of heat
exchange tubes; an evaporator to transfer heat from said steam to
an Organic Rankine Cycle (ORC) working fluid to evaporate said ORC
working fluid to produce a high pressure ORC vapor and to condense
said steam to provide purified water, said evaporator having a
steam input port functionally connected to said steam output port
of said boiling tank to receive said steam, a condensate port for
discharging said purified water, a working fluid input port to
receive said working fluid, and a vapor output port for discharging
said high pressure ORC vapor; a turbine to produce mechanical power
from said high pressure ORC vapor, said turbine having a high
pressure vapor input port functionally connected to said evaporator
to receive said high pressure ORC vapor, and a low pressure vapor
output port to discharge a low pressure ORC vapor; a condenser to
transfer heat from said low pressure ORC vapor to a cooling fluid
to condense said low pressure ORC vapor to produce an ORC working
fluid, said condenser having a low pressure vapor input port
functionally connected to said low pressure vapor output port of
said turbine for receiving said low pressure ORC vapor, an ORC
working fluid condensate output port for discharging said ORC
working fluid, a cooling fluid input port to receive said cooling
fluid, and a cooling fluid output port to discharge said cooling
fluid; and a pump to provide said ORC working fluid to said
evaporator, said pump having an ORC working fluid input port
functionally connected to said ORC working fluid condensate output
port, and an ORC working fluid output port functionally connected
to said working fluid input port of said evaporator.
2. The apparatus of claim 1 wherein said ORC working fluid has a
boiling point below the boiling point of water.
3. The apparatus of claim 1 wherein said ORC working fluid is
either heptane or pentane.
4. The apparatus of claim 1 and further comprising an electrical
generator, functionally connected to said turbine, to generate
electricity.
5. The apparatus of claim 1 and further comprising a collection
tank to collect said purified water.
6. A power generation and water purification apparatus, comprising:
a combustion chamber to burn a fuel to provide combustion products,
and having a fuel input port to receive said fuel; a boiling tank,
heated by said combustion products, and having a water input port
to receive water and a steam output port to discharge steam; an
evaporator to transfer heat from said steam to an Organic Rankine
Cycle (ORC) working fluid to evaporate said ORC working fluid to
produce a high pressure ORC vapor and to condense said steam to
provide purified water, said evaporator having a steam input port
functionally connected to said steam output port of said boiling
tank to receive said steam, a condensate port for discharging said
purified water, a working fluid input port to receive said working
fluid, and a vapor output port for discharging said high pressure
ORC vapor; a turbine to produce mechanical power from said high
pressure ORC vapor, said turbine having a high pressure vapor input
port functionally connected to said evaporator to receive said high
pressure ORC vapor, and a low pressure vapor output port to
discharge a low pressure ORC vapor; a condenser to transfer heat
from said low pressure ORC vapor to a cooling fluid to condense
said low pressure ORC vapor to produce an ORC working fluid, said
condenser having a low pressure vapor input port functionally
connected to said low pressure vapor output port of said turbine
for receiving said low pressure ORC vapor, an ORC working fluid
condensate output port for discharging said ORC working fluid, a
cooling fluid input port to receive said cooling fluid, and a
cooling fluid output port to discharge said cooling fluid; and a
pump to provide said ORC working fluid to said evaporator, said
pump having an ORC working fluid input port functionally connected
to said ORC working fluid condensate output port, and an ORC
working fluid output port functionally connected to said working
fluid input port of said evaporator.
7. The apparatus of claim 6 wherein said ORC working fluid has a
boiling point below the boiling point of water.
8. The apparatus of claim 6 wherein said ORC working fluid is
either heptane or pentane.
9. The apparatus of claim 6 and further comprising an electrical
generator, functionally connected to said turbine, to generate
electricity.
10. The apparatus of claim 6 and further comprising a collection
tank to collect said purified water.
11. A method to generate power and purify water, comprising: (a)
burning a fuel to provide a hot gas; (b) transferring heat from
said hot gas to convert water into steam; (c) transferring heat
from said steam to convert an Organic Rankine Cycle (ORC) working
fluid into a high pressure ORC vapor and to provide condensate from
said steam as purified water; (d) providing said high pressure ORC
vapor to a turbine to generate power and to provide a low pressure
ORC vapor; (e) cooling said low pressure ORC vapor to provide an
ORC working fluid condensate; and (f) pumping said ORC working
fluid condensate to be used as said ORC working fluid in (c).
12. The method of claim 11 wherein said ORC working fluid has a
boiling point below the boiling point of water.
13. The method of claim 11 wherein said ORC working fluid is either
heptane or pentane.
14. The method of claim 11 and further comprising automatically
providing said water to be converted into steam.
15. The method of claim 11 wherein a cooling fluid is used to cool
said low pressure ORC vapor.
16. The method of claim 11 wherein water is used to cool said low
pressure ORC vapor.
17. The method of claim 11 and further comprising collecting said
purified water.
18. The method of claim 11 wherein waste biomass is burned as said
fuel to provide said hot gas.
19. The method of claim 11 wherein said power is used to generate
electricity.
Description
PRIORITY CLAIM
[0001] This application claims the priority of U.S. Provisional
Patent Application Ser. No. 61/296,142, filed Jan. 19, 2010,
entitled "Simultaneous Production Of Electrical Power And Potable
Water".
FIELD OF THE INVENTION
[0002] The present invention relates to a process to produce both
potable water and electrical power.
BACKGROUND OF THE INVENTION
[0003] Nearly a billion people worldwide do not have access to
clean water and one quarter of the earth's human population does
not have access to electricity. The vast majority of the people
that live without clean water and electricity are located in rural
areas of the developing world. In addition, it is often impractical
to build or reliably operate even a small oil-fired or coal-fired
power plant or water purification plant because it may be difficult
or even impossible to transport these oil or coal fuels to a power
plant or a purification plant in such rural areas because of the
distance or terrain involved. Often, the sole fuels available in
these areas are locally available biomass fuels or wastes. Further,
even in those countries that do normally have potable water and
electricity, such necessities can be disrupted, briefly or for
extended periods, by natural disasters such as hurricanes,
earthquakes, flooding, landslides, and tidal waves.
SUMMARY OF THE INVENTION
[0004] An apparatus which both generates power and purifies water
is disclosed. The apparatus includes a combustion chamber, a
boiling tank, a preferred, but optional, plurality of heat exchange
tubes, an exhaust conduit, an evaporator, a turbine, a condenser,
and a pump. The combustion chamber burns fuel to provide heat via
combustion products, and has a fuel input port. The boiling tank
has a water input port and a steam output port. The preferred, but
optional, heat exchange tubes are connected in parallel, and are
functionally connected to the combustion chamber to receive the
combustion products. The tubes are at least partially inside the
boiling tank and transfer heat from the combustion products to the
water in the boiling tank to produce steam. Alternatively, the heat
from the combustion products can be used to directly heat the
boiling tank. The exhaust conduit, such as a chimney, discharges
combustion products which have flowed through the heat exchange
tubes. The evaporator transfers heat from the steam to an Organic
Rankine Cycle (ORC) working fluid to evaporate the ORC working
fluid to produce a high pressure ORC vapor and to condense the
steam to provide purified or potable water. The evaporator has a
steam input port functionally connected to the steam output port of
the boiling tank to receive the steam, a condensate port for
discharging the purified or potable water, a working fluid input
port to receive the working fluid, and a vapor output port for
discharging the high pressure ORC vapor. The turbine produces
mechanical power from the high pressure ORC vapor. The turbine has
a high pressure vapor input port functionally connected to the
evaporator to receive the high pressure ORC vapor, and a low
pressure vapor output port to discharge a low pressure ORC vapor.
The condenser transfers heat from the low pressure ORC vapor to a
cooling fluid to condense the low pressure ORC vapor to produce an
ORC working fluid. The condenser has a low pressure vapor input
port functionally connected to the low pressure vapor output port
of the turbine for receiving the low pressure ORC vapor, an ORC
working fluid condensate output port for discharging the ORC
working fluid, a cooling fluid input port to receive the cooling
fluid, and a cooling fluid output port to discharge the cooling
fluid. The pump provides the ORC working fluid to the evaporator.
The pump has an ORC working fluid input port functionally connected
to the ORC working fluid condensate output port, and an ORC working
fluid output port functionally connected to the working fluid input
port of the evaporator.
[0005] A method which both generates power and purifies water is
disclosed. The method includes burning a fuel to provide a hot gas,
transferring heat from the hot gas to convert water into steam,
transferring heat from the steam to convert an Organic Rankine
Cycle (ORC) working fluid into a high pressure ORC vapor and to
provide condensate from the steam as purified or potable water,
providing the high pressure ORC vapor to a turbine to generate
power and to provide a low pressure ORC vapor, cooling the low
pressure ORC vapor to provide an ORC working fluid condensate, and
pumping the ORC working fluid condensate to be used as the ORC
working fluid.
BRIEF DESCRIPTION OF THE DRAWING
[0006] FIG. 1 is a schematic block diagram of an exemplary
embodiment of a water purification and sterilization and power
generation system.
[0007] FIG. 2 is a schematic block diagram of an exemplary
embodiment of a combustion chamber and evaporation system.
DETAILED DESCRIPTION OF THE INVENTION
[0008] Biomass, refuse-derived fuels, and construction
debris-derived fuels are used as an input to a water
desalination/purification and electrical generation process. The
water purification process is suitable for both the separation of
dissolved components as well as the thermal pasteurization/
sterilization of the water. Suitable water inputs are seawater,
brackish water and even water containing those waterborne diseases
and pathogens which can be killed through
pasteurization/sterilization.
[0009] Biomass or carbon-containing feeds are combusted in a
boiler. The heat of combustion is used to evaporate water from a
saline, brackish, or contaminated water source. The resulting steam
is used as a heat input into an Organic Rankine Cycle (ORC) and the
condensed steam is then collected for use as potable water. The ORC
can drive a turbine which, in turn, drives a generator which can
produce electrical power. Also, the rotation of the turbine can be
used directly as mechanical energy into a direct drive application
such as, but not limited to, pumping water.
[0010] Turning now to FIGS. 1 and 2, a power generation and water
purification and sterilization apparatus 5 preferably includes a
combustion chamber 15, a boiling tank 20, a plurality of heat
exchange tubes 23 (FIG. 2), an exhaust conduit 27, an evaporator
30, a turbine 50, a condenser 60, and a pump 75.
[0011] The combustion chamber 15 burns fuel to provide heat energy
via combustion products, and has a fuel input port 14.
[0012] The boiling tank 20 has a water input port 21 and a steam
output port 22.
[0013] The heat exchange tubes 23 are connected in parallel, and
are connected to the combustion chamber to receive the combustion
products. The tubes are at least partially inside the boiling tank,
are at least partially submerged in the water in the tank, and
transfer heat from the combustion products to the water in the
boiling tank to produce steam.
[0014] The exhaust conduit 27, such as a chimney, discharges
combustion products which have flowed through the heat exchange
tubes.
[0015] The evaporator 30 transfers heat from the steam to an
Organic Rankine Cycle (ORC) working fluid to evaporate the ORC
working fluid to produce a high pressure ORC vapor and to condense
the steam to provide potable water. The evaporator 30 has a steam
input port 31 connected via a steam line 25 to the steam output
port 22 of the boiling tank to receive the steam, a condensate
output port 32 for discharging the potable water, a working fluid
input port 33 to receive the working fluid, and a vapor output port
34 for discharging the high pressure ORC vapor.
[0016] The turbine 50 produces mechanical power from the high
pressure ORC vapor. The turbine is preferably, but not necessarily,
a centrifugal, rotary lobe, or rotary screw turbine. The turbine
has a high pressure vapor input port 51 connected via an ORC vapor
high pressure line 45 to the evaporator to receive the high
pressure ORC vapor, and a low pressure vapor output port 52 to
discharge the ORC vapor, which will be at a low pressure after
transferring its energy to the turbine.
[0017] The condenser 60 receives the low pressure ORC vapor and
transfers heat from the low pressure ORC vapor to a cooling fluid
to condense the low pressure ORC vapor to produce an ORC working
fluid. The condenser 60 has a low pressure vapor input port 61
connected to the low pressure vapor output port 52 of the turbine
via an ORC vapor low pressure line 55 for receiving the low
pressure ORC vapor, an ORC working fluid condensate output port 62
for discharging the ORC working fluid, a cooling fluid input port
63 to receive the cooling fluid, and a cooling fluid output port 64
to discharge the cooling fluid. If the cooling fluid is water then
the condenser is preferably, but not necessarily, a shell and tube
and plate heat exchanger. If the cooling fluid is air then the
condenser is preferably, but not necessarily, a wet surface air
cooler or an air fin cooler.
[0018] The pump 75 provides the ORC working fluid to the
evaporator. The pump 75 has an ORC working fluid input port 76
connected to the ORC working fluid condensate output port 62, and
an ORC working fluid output port 77 connected to the working fluid
input port 33 of the evaporator.
[0019] FIG. 1 is a schematic block diagram of an exemplary
embodiment of water sterilization and power generation system 5.
Seawater or other non-potable water is provided via a water line 17
to the water input port 21 of a boiling tank, such as a
desalinization evaporator 20. A biomass fuel 10 is provided to the
fuel input port 14 of a combustion chamber, such as firebox 15. The
fuel input port may be, for example, a hinged door or even just an
opening in the side of the combustion chamber. The hot gas from the
combustion chamber drives the boiling tank 20 to produce steam.
Although almost any available fuel can be utilized as long as it
combusts in an exothermic manner, the preferred fuel input to the
process is biomass fuel, such as, but not limited to, biomass,
biomass-derived fuel, or refuse-derived fuel. Examples of such
fuels are sticks, leaves, brush, husks, stems, plants, logs, lumber
as used as a building material, combustible debris, construction
debris, etc. For example, after harvesting crops, there is a
substantial amount of plant stems and husks available for use as
fuel. As another example, after a natural disaster, such as a
tornado, there is a substantial quantity of wood debris and other
combustible debris readily available. The open nature of the
firebox allows fuels with a large range of characteristic lengths
and sizes to be used. This minimizes front end processing such as,
pelletizing, chipping, or cutting to a specified size. If
refuse-derived fuels (including, but not limited to, papers,
cardboards, plastics, food wrappers and vegetable matter) are used,
it may be advantageous, although not necessary, to coarsely
briquette or pelletize the material to improve handling and/or
combustion characteristics. Fuel with a wide range of moisture
content also can be used, as long as it combusts in a net
exothermic manner, thus minimizing the need for external drying of
the fuel. It should be noted, however, that external drying
increases the combustion characteristic of the fuel, and can reduce
or slow the buildup of incomplete combustion products, such as tar
and creosote, in the firebox, heat exchange tubes, and chimney. Use
of local biomass fuel is advantageous in that it is generally
available, costs less than processed fuels such as oil, gas, and
coal, and does not require an extensive or specialized
transportation system, such as pipelines or rail lines. It is also
advantageous in that it provides a facility for useful disposal of
such biomass, that is, in creating potable water and power.
Otherwise, the biomass would be disposed of in a landfill, burned
simply to dispose of it, or simply left in a pile somewhere to rot
or decay, none of which are environmentally-friendly
approaches.
[0020] FIG. 2 is a schematic block diagram of an exemplary
embodiment of a combustion chamber 15 and evaporation system 20.
The biomass input 10 is combusted in a front end "firebox" or
combustion chamber 15. The products of combustion, primarily hot
gas and ash, then pass through a saline boiling tank 20 via a
plurality of heat transfer (HX) tubes 23 which are submerged in the
water to be purified. The tank 20 has an input port 21 for
receiving the water via water line 17. After passing through the
heat transfer tubes the at least partially cooled products of
combustion are vented to the atmosphere through a conduit, such as
a chimney 27.
[0021] In an alternative embodiment (not shown), the heat exchange
tubes are not used but, instead, the heat of the combustion
products is used to directly heat the boiling tank. This
embodiment, however, provides for less efficient transfer of the
heat of combustion to the water and, therefore, is not preferred.
Other combustor-evaporator configurations are possible as long as
the configuration provides for combusting the feedstock to produce
heat and for passing some of the heat of combustion to boil water
to produce steam.
[0022] The heat of combustion is primarily transferred via the
combustion products and boils the water in the tank 20 to produce
steam. The resulting steam is provided via a steam outlet port 22
to the subsequent power generation and steam condensation processes
shown in FIG. 1. Although not shown, it will be appreciated that
there should also be some means to replenish the feedstock 10 and
the input water as they are consumed, preferably automatically, but
at least manually. Replenishment of either may be on a batch basis,
a continuous basis, or some combination thereof. The design of the
combustion chamber is not critical but preferably includes a
plurality of air inlets (not shown) situated in numerous locations
to allow primary, secondary, and below-grate air injections or
infiltration to allow for adequate air intake and combustion of the
biomass. The combustion chamber is preferably, but not necessarily,
insulated and preferably, but not necessarily, includes a grate,
mechanical grate, moving grate, or other device (not shown) which
promotes the flow of ash into a lower ash collection bin 18 for
convenient removal and/or at least so that the ash or other
unburned or partially-burned residue does not build up and encumber
the combustion process.
[0023] Returning to FIG. 1, it can be seen that once the water
begins to boil and produce steam then the produced steam is
provided via an output port 21 and a steam line 25 to a steam input
port 31 of the ORC evaporator/heat exchanger 30. The steam is
condensed in the ORC evaporator and the condensate is provided via
a condensate output port 32 and routed via a condensed water line
35 to be collected in the potable water storage tank 40 for later
consumption or other use. The process of conversion of the input
water to steam, and then the resulting condensation, removes and/or
kills most pathogens which may be present in the input water. This
process also removes many contaminants which may be present in the
input water as they are left behind in the tank 20 when the water
evaporates. If, however, a contaminant has a boiling point below
the boiling point of water then that contaminant may still be
present in the condensate and may have to be removed by other
means.
[0024] The ORC cycle is similar to a steam Rankine cycle, which
used in many electrical power generation facilities, except that,
in this case, the working fluid has a lower boiling point than
water and, preferably, has a much lower boiling point than water.
The working fluid should also have acceptable boiling point versus
pressure properties; that is, the change from a liquid to a gas
should cause a substantial increase in the pressure. In addition,
the working fluid is preferably non-corrosive and stable, that is,
does not readily decompose under the expected operating conditions.
Examples of acceptable working fluids are refrigerants, alphiphatic
hydrocarbons such as, but not limited to, heptane and pentane,
alcohols, such as but not limited to methanol. Utilizing a working
fluid with a low boiling point allows adequate working pressure to
be generated using much lower temperature heat and low pressure
from the boiling tank than with a conventional steam Rankine cycle.
This is advantageous from both mechanical and safety viewpoints.
The use of lower temperature heat, such as steam at 212 .degree.
F., is much safer to use and is easier on equipment than, for
example, superheated steam. Also, the use of an atmospheric or low
pressure in the boiling tank is much safer to use, and is much
simpler to construct and maintain, than a high-pressure superheated
steam system.
[0025] In the preferred embodiment, the temperature and pressure on
the ORC high pressure vapor line are 5 to 70 bar and 50 to
150.degree. C., and, more preferably, 5 to 30 bar and 50 to
130.degree. C.
[0026] Normally, in a desalinization or water purification process,
the energy released during condensation of the steam is either used
to aid in the desalinization process, such as by pre-heating the
incoming water, or is simply vented to the atmosphere as waste
heat. However, in the preferred embodiment, the steam from the
desalination process is condensed in the ORC evaporator, and the
energy released thereby is used to boil the ORC working fluid and
to generate a high pressure. The working fluid vapor is then
provided to, via a high pressure vapor line 45, and used to, power
a turbine 50 which transforms the pressure into a mechanical
rotation. The preferred application of the rotation is to turn a
drive shaft 53 to drive a generator 54 to produce electrical power,
but the rotation can be used to power any direct drive application,
such as, for example, to pump water for irrigation or to replenish
the input water and/or cooling water, or to drive another
mechanical process, such as a mill.
[0027] The working fluid then flows from the turbine 50 via a lower
pressure vapor line 55 to a condenser 60 which returns the working
fluid back to a liquid state prior to being pumped by a circulation
pump 75 back into the ORC evaporator. It will be appreciated that
it may be necessary to operate the circulation pump manually or by
another power source, such as a battery, until the generator begins
producing enough electrical power to operate the circulation pump.
A cooling fluid, such as water, is provided via a cooling fluid
input conduit or water line 65 to the ORC condenser 60. The warmed
cooling fluid is then provided via a cooling fluid output conduit
70 to a discharge location or other process. The cooling fluid may
be used to provide local district heating, may be discharged
directly into the environment, or may be returned to its source,
such as a river. Alternatively, some of the warmed cooling fluid
may be used as an input liquid to the evaporator 20. In areas where
fire is a hazard, this cooling fluid water may be sprayed into the
chimney 27 to quench any sparks and reduce the likelihood of
starting a fire. An air cooled condenser may also be used.
[0028] Returning to FIGS. 1 and 2, two different configurations of
the firebox and boiling tank are shown. In FIG. 1 the combustion
products flow from the firebox to and through the heat exchange
tubes in the boiling tank, and then from the tubes via a return
path (which may be more tubes) to a chimney at the top of the
firebox. In FIG. 2 the combustion products flow from the firebox to
and through the tubes in the boiling tank and then to a chimney
which is not part of the firebox. Thus, in both configurations, the
combustion products flow through the heat exchange tubes and
thereby heat up the water in the boiling tank so that steam is
produced.
[0029] The size of the heat exchange tubes is not critical but the
tubes should be large enough to allow good heat transfer to the
water and to allow the combustion products to flow through the
tubes without pressure buildup in the firebox, but should not so
large that a significant portion of the energy escapes though the
chimney or that condensation of water vapor or other combustion
products occurs in the tubes. For example, if the tubes are too
short and/or too wide then the energy transfer will be less than
desired and the exhaust gases going to the chimney 27 will be
hotter than desired. Conversely, if the tubes are too long and/or
too narrow then the pressure drop through the tubes will be
excessive and the firebox may become hotter than desired or the
exhaust gases may be forced out of the fuel and/or air input ports
of the firebox. Also, the composition of the heat exchange tubes is
not critical, but should be of a material which can withstand the
heat of the combustion products and is not degraded, or is only
slowly degraded, by the heat, the combustion products, the water
being heated, or chemicals or contaminants which may be in the
water. For example, in one embodiment, 44 exchange tubes were used,
and each exchange tube was made stainless steel 304 tubing, and had
a length of about 1.2 meters, an inner diameter of 22 mm, and a
wall thickness of 1.7 mm.
[0030] Due to the nature of the particular biomass and the input
water used, the inner and/or outer surfaces of the tubes 23 in the
tank 20 may become coated with soot, scale, etc., and the
efficiency of the heat transfer will thereby eventually be reduced
or even severely hampered. Therefore, it is preferred that the tank
20 be constructed so that it can be disassembled to expose the
tubes 23. The tubes 23 can then be steam-cleaned, brushed and/or
scoured, chemically treated, etc., as necessary, to remove the
buildup and restore them to good operating condition.
[0031] Electrical and/or mechanical power is produced and,
simultaneously, water is desalinated/sterilized to produce potable
water by combusting a carbon-containing feedstock to produce heat,
using some of the heat of combustion to evaporate water to produce
steam, using the steam as a heat source in a process, such as an
ORC process, which converts low grade thermal energy into
mechanical or electrical energy, producing a condensate from the
steam, collecting the condensate and providing the condensate as
potable water.
[0032] Thus, a single combustor/evaporator unit provides steam
which is used both to transfer energy to another process, such as
an ORC process, and to provide potable water. The heat of
combustion is thus serially used twice: (1) to convert water into
steam, thereby purifying it, and (2) to boil the ORC working fluid
to create pressure to turn the turbine. Thus, potable water and
electrical and/or mechanical power are simultaneously produced. In
one test embodiment, sufficient steam was available to drive a 10
KW generator and produce 40 gallons/hour of potable water. The size
of the system is configured depending upon the resources locally
available and the needed results. Thus, a smaller unit would be
preferable in a situation where fuel and/or water are locally
limited, and a larger unit would be preferable where those
resources are more locally available. Further, the size of the
units can be made such that they are portable. Thus, in areas where
the where electrical power and potable water are scarce or
non-existent, either because of natural conditions or because of a
natural disaster, electrical power and potable water can be quickly
and readily provided by using locally available biomass and
water.
[0033] The present invention enhances the quality of the
environment by reducing the quantity of material going to
landfills, reduces green house gas emission by using materials that
might otherwise simply be burned, and conserves energy resources by
providing useful products and services, such as potable water and
mechanical and/or electrical power, from materials that might
otherwise be simply burned or tossed into a landfill to dispose of
them.
[0034] Conditional language, such as, among others, "can", "could",
"might", or "may", unless specifically stated otherwise, or
otherwise understood within the context as used, is generally
intended to convey that certain embodiments optionally could
include, while some other embodiments do not include, certain
features, elements and/or steps. Thus, such conditional language
indicates, in general, that those features, elements and/or step
are not required for every implementation or embodiment.
[0035] The above has been presented for purposes of illustration
and description. It is not intended to be exhaustive or to limit
the disclosure to the precise forms, structures or embodiments
disclosed. Obvious modifications or variations are possible in
light of the above teachings. The implementations discussed above
illustrate the principles of the invention and its practical
application and thereby enable one of ordinary skill in the art to
utilize the disclosure in various implementations and with various
modifications as are suited to the particular use contemplated. All
such modifications and variations are within the scope of the
disclosure as determined by the appended claims when interpreted in
accordance with the breadth and equivalents to which they are
legally entitled.
* * * * *