U.S. patent application number 12/682695 was filed with the patent office on 2011-02-24 for method for carrying out pyrolysis.
This patent application is currently assigned to Valtion Teknillinen Tutkimuskeskus. Invention is credited to Pekka Jokela, Markku Raiko, Kai Sipila, Yrjo Solantausta.
Application Number | 20110041388 12/682695 |
Document ID | / |
Family ID | 38656868 |
Filed Date | 2011-02-24 |
United States Patent
Application |
20110041388 |
Kind Code |
A1 |
Sipila; Kai ; et
al. |
February 24, 2011 |
METHOD FOR CARRYING OUT PYROLYSIS
Abstract
The invention relates to a method for carrying out pyrolysis in
such manner that a first raw material is fed to a combustion boiler
and a second raw material is fed to a pyrolysis reactor which are
integrated together, energy fractions are formed from the raw
material in the combustion boiler and gaseous and liquid product
fractions are formed from the raw material in the pyrolysis reactor
by fast pyrolysis. According to the invention, production of the
pyrolysis product and energy fractions is controlled by optimizing
the selection of the raw material, product distribution and
production costs, value and quality of at least one product
fraction by varying the process variables, which are selected from
the group comprising a first raw material, a second raw material,
quantities of the raw materials, selection of additional materials,
process parameters, selection of an additional process step,
composition and quantity of the carrier gas used, quantity of
oxygen, selection of the heat transfer agent and moisture content
of the raw material.
Inventors: |
Sipila; Kai; (Espoo, FI)
; Solantausta; Yrjo; (Helsinki, FI) ; Jokela;
Pekka; (Espoo, FI) ; Raiko; Markku; (Hyvinkaa,
FI) |
Correspondence
Address: |
MERCHANT & GOULD PC
P.O. BOX 2903
MINNEAPOLIS
MN
55402-0903
US
|
Assignee: |
Valtion Teknillinen
Tutkimuskeskus
Espoo
FI
|
Family ID: |
38656868 |
Appl. No.: |
12/682695 |
Filed: |
October 8, 2008 |
PCT Filed: |
October 8, 2008 |
PCT NO: |
PCT/FI2008/050558 |
371 Date: |
July 12, 2010 |
Current U.S.
Class: |
44/349 ; 201/20;
201/3 |
Current CPC
Class: |
C10B 49/22 20130101;
C10J 2300/0956 20130101; C10J 2300/1659 20130101; Y02E 50/10
20130101; C10J 2300/0916 20130101; C10J 3/482 20130101; C10B 53/02
20130101; C10J 3/66 20130101; C10J 2300/1637 20130101; C10J
2300/1665 20130101; C10J 2300/1246 20130101; C10J 2300/1606
20130101; C10K 3/006 20130101; C10J 2300/0993 20130101 |
Class at
Publication: |
44/349 ; 201/20;
201/3 |
International
Class: |
C10L 1/188 20060101
C10L001/188; C10B 49/00 20060101 C10B049/00; C10B 53/00 20060101
C10B053/00 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 11, 2007 |
FI |
20075721 |
Claims
1. A method for carrying out pyrolysis in such manner that a first
raw material is fed to a combustion boiler and a second raw
material is fed to a pyrolysis reactor which are integrated
together, energy fractions are formed from the raw material in the
combustion boiler and gaseous and liquid product fractions are
formed from the raw material in the pyrolysis reactor by fast
pyrolysis, characterized in that production of the pyrolysis
product and energy fractions is controlled by optimizing the
selection of the raw material, the product distribution and the
production costs, value and quality of at least one product
fraction by varying the process variables, which are selected from
the group comprising a first raw material, second raw material,
quantities of the raw materials, selection of additional materials,
process parameters, selection of an additional process step,
composition and quantity of the carrier gas used, quantity of
oxygen, selection of a heat transfer agent and moisture content of
the raw material.
2. The method according to claim 1, characterized in that the
gaseous product fractions produced during the pyrolysis are mainly
condensed to liquid pyrolysis products.
3. The method according to claim 1 or 2, characterized in that the
raw material is selected from the group comprising organic matter,
chips, forest chips, wood, bark, sawdust, straw, coal, peat, oil,
oil shale, lignite, petroleum, biomass, energy containing waste
material, plastic, waste plastic, fuel containing waste, refuse
derived fuel/RDF, pine oil, black lye, organic solvent and
derivatives thereof.
4. The method according to any one of claims 1 to 3, characterized
in that the method comprises a multistep pyrolysis, wherein fast
pyrolysis is performed as a first step and improved product
fractions and/or additional product fractions are formed as a
second step by applying an additional step.
5. The method according to any one of claims 1 to 4, characterized
in that the method comprises a multistep pyrolysis, wherein an
additional step is performed as a first step and fast pyrolysis is
performed as a second step in order to form improved product
fractions and/or additional product fractions.
6. The method according to claim 4 or 5, characterized in that the
additional step is selected from the group comprising: drying,
temperature raising step, gasification step, dust separation,
reforming, steam reforming, separating the product fractions and
separating the solids.
7. The method according to any one of claims 1 to 6, characterized
in that the realization of the pyrolysis step is modified in the
method by at least one special operation, which is selected from
the group comprising adjusting the temperature, selecting the
carrier gas, feeding vapor and adding oxygen.
8. The method according to any one of claims 1 to 7, characterized
in that the carrier gas is selected from the group comprising
combustion gas, water vapor, air and a mixture thereof.
9. The method according to any one of claims 1 to 8, characterized
in that the carrier gas contains oxygen.
10. The method according to any one of claims 1 to 9, characterized
in that additional oxygen is added to the carrier gas.
11. The method according to any one of claims 1 to 10,
characterized in that most of the side, residual and waste flows
are circulated to the combustion boiler.
12. The method according to any one of claims 1 to 11,
characterized in that heat transfer material is used for
transferring the energy fraction from the combustion boiler to a
desired process step and/or recovery.
13. The method according to any one of claims to 12, characterized
in that the heat transfer material is selected from the group
comprising sand, bed sand, aluminum oxide based material, other
fluidization material and the like.
14. The method according to any one of claims to 13, characterized
in that the heat transfer material is circulated from the
combustion boiler to the pyrolysis reactor and from the pyrolysis
reactor to the combustion boiler via a separation step.
15. The method according to any one of claims 1 to 14,
characterized in that the process parameters are selected from the
group comprising temperature of the pyrolysis step, temperature of
the additional step, residence time in the pyrolysis reactor,
temperature of the combustion boiler, way of mixing and order of
mixing the raw materials of the pyrolysis, the carrier gas and the
heat transfer material, addition of oxygen, circulation of the heat
transfer material and circulation of the product and side
fractions.
16. The method according to any one of claims 1 to 15,
characterized in that the first raw material and the carrier gas
are arranged to a mixture and the heated heat transfer material is
conducted to the mixture.
Description
FIELD OF THE INVENTION
[0001] The invention relates to a method defined in the preamble of
claim 1 for carrying out pyrolysis in such manner that a first raw
material is fed to a combustion boiler and a second raw material is
fed to a pyrolysis reactor which are integrated together, energy
fractions are formed from the raw materials in the combustion
boiler and gaseous and liquid product fractions are formed from the
raw materials in the pyrolysis reactor by fast pyrolysis.
BACKGROUND OF THE INVENTION
[0002] It is known from the prior art that a pyrolysis product,
i.e. pyrolysis liquid or pyrolysis gas, is produced from different
kinds of biomasses or organic materials such as wood, bark, paper,
straw, waste plastic, oil shale, lignite, peat or the like by dry
distillation with the pyrolysis technique. The pyrolysis is
typically performed in oxygen-free conditions at a temperature of
about 300 to 800.degree. C. When slow heating rate is applied, the
pyrolysis liquid, e.g. wood tar from dry wood, can typically be
recovered in an amount of about 20 to 30% by weight. The amount of
the pyrolysis liquid increases when the fast pyrolysis method is
applied. There are many known fast pyrolysis methods for producing
pyrolysis products and chemicals.
[0003] Fast pyrolysis is typically carried out by heating the fuel
to be pyrolyzed in a hot oxygen-free gas flow by introducing the
required heat to the pyrolyzer by means of a heating gas, heat
exchanger or heat transfer agent, e.g. sand or aluminum oxide based
carrier. A bubbling or sand circulating fluidized-bed reactor may
be used as the pyrolyzer. The produced pyrolysis steam is condensed
to a temperature of less than 150.degree. C. to form the pyrolysis
liquid.
[0004] The fuel to be pyrolyzed, e.g. biomass, may be conducted to
a dryer before the pyrolyzer for drying in order to reduce the
water content of the pyrolysis liquid that is being formed.
Normally used are the known drum, flash or fluidized-bed dryers
which typically comprise combustion gas or water vapor as the
drying gas. It is also known to use a steam dryer in which the heat
is introduced by means of hot sand to the dryer operating on the
fluidized-bed basis and in which only water is removed. The
temperature is kept at such level that organic compounds do not
escape. EP publication 513051 (Ensyn Technologies Inc.) describes a
method and apparatus for producing a pyrolysis liquid from fuels by
fast pyrolysis in such manner that the circulating mass reactor
which operates as the pyrolyzer comprises separate mixing and
reactor zones. The heat transfer to the fuel particles is effected
by using heat transporting sand or an alumina-silica catalyst
having the average particle size from 40 to 500 .mu.m as the heat
transfer agent. The method uses an oxygen-free carrier gas. The
feeding material in particle form, oxygen-free carrier gas and hot
heat-transporting particle material are mixed together in the base
section of the reactor, and the mixture is transported upwards to a
reactor section in which the feeding material is converted to
products. The contact time between the feeding material and the
heat transporting material is less than 1.0 seconds. The heat
transporting particle material is separated from the product
fractions and recirculated to the reactor. In the method, the mass
ratio of the heat transfer material to the fuel is greater than
5:1.
[0005] Also known from prior art is the use of an oxidizing reactor
for processing sand that exits the pyrolyzer and coke produced
during the pyrolysis. In the oxidizing reactor, coke is burned and
sand is heated and recirculated to the pyrolyzer. The ratio of the
oxidizing reactor power to the pyrolyzer fuel power is typically
1:5. This type of oxidizing reactor is designed to primarily burn
only the coke produced during the pyrolysis and the non-condensible
gases. Therefore, the heat content of the coke and non-condensible
gases is, by the energy balance, a limiting factor in the mass feed
to the pyrolyzer.
[0006] A problem with the known pyrolysis processes is the need for
additional fuel in the pyrolyzer and in the additional equipment,
such as the dryer, and the possible drifting of the water that has
been vaporized in the process to the pyrolysis oil. Normally, the
water vaporized for example in the dryer is condensed or conducted
to outside air. When the vaporized water contains organic dry
distillation products, application of the process becomes
problematic due to environmental nuisances, e.g. strong odors.
Further, the known devices do not permit utilization of different
process flows, side flows and unwanted intermediate/end products in
the process in an efficient manner.
[0007] Furthermore, it is previously known from patent FI 117512 by
the same applicant to integrate the pyrolyzer and the combustion
boiler to one assembly.
OBJECTIVE OF THE INVENTION
[0008] The objective of the invention is to eliminate the
above-mentioned problems and to disclose a novel method for use in
carrying out pyrolysis and different ways of running the pyrolysis,
and in optimizing the pyrolysis and energy product distribution.
One specific objective of the invention is to disclose a method for
producing simultaneously heat energy and a pyrolysis product in an
industrial scale and environmentally friendly manner by circulating
and utilizing the process flows that are produced during the
process.
SUMMARY OF THE INVENTION
[0009] The method according to the invention is characterized by
what has been presented in the claims.
[0010] The invention is based on a method for producing pyrolysis
and energy products in a flexible manner and for carrying out and
enhancing the pyrolysis in such manner that a first raw material or
mixture of raw materials is fed to a combustion boiler and a second
raw material or mixture of raw materials is fed to a pyrolysis
reactor, which are integrated together, energy fractions are formed
from the raw materials in the combustion boiler in the form of
heat, electricity, steam or gas, and gaseous and liquid product
fractions are formed from the raw materials in the pyrolysis
reactor by fast pyrolysis. According to the invention, production
of the pyrolysis product and energy fractions is controlled by
optimizing the raw material and the selection thereof, such as
availability, costs and quantity, product distribution and
production costs, value on the market and quality of at least one
product fraction, preferably the production costs, value on the
market and quality of a number of product fractions, by varying the
process variables, preferably more than one process variable, which
are selected from the group comprising a first raw material, second
raw material, quantities of the raw materials, selection of
additional materials, process parameters, selection of an
additional process step, composition and quantity of the carrier
gas used, quantity of oxygen, selection of the heat transfer agent
and moisture content of the raw material.
[0011] In this context, the first raw material refers to a raw
material or a mixture of raw materials to be fed to the combustion
boiler. In this context, the second raw material refers to a raw
material or a mixture of raw materials to be fed to the pyrolysis
reactor. The first and the second raw material may be identical,
partly similar or completely different in composition. In one
embodiment, substantially different raw materials are fed to the
combustion boiler and the pyrolysis reactor in order to maximize
the efficiency ratio between the combustion and the pyrolysis and
yield of the pyrolysis product.
[0012] In the method according to the invention, the process is
preferably run systemically by optimizing the raw material to be
selected, the product distribution, the quantity and quality of the
product. In one embodiment, the proportion of the most valuable
product fractions is maximized.
[0013] Preferably, the integrated combustion boiler supports the
carrying out and success of the pyrolysis.
[0014] In one embodiment of the invention, the raw materials, which
are in the form of a solid, liquid, vapor or gas, are selected from
the group comprising organic matter, chips, forest chips, wood,
bark, sawdust, straw, coal, peat, oil, oil shale, lignite,
petroleum, biomass, energy containing waste material, plastic,
waste plastic, fuel containing waste, refuse derived fuel/RDF, pine
oil, black lye, organic solvent and derivatives thereof. In one
embodiment, the raw material or raw materials may be selected e.g.
from adjacent containers, depending on what kind of product
distribution is desired.
[0015] In one embodiment, the energy and pyrolysis product
fraction, which is in the form of a solid, liquid, vapor or gas, is
included in the group comprising pyrolysis gas, pyrolysis steam,
pyrolysis liquid, pyrolysis oil, black lye, pine oil soap, fuel,
chemicals, carbon fiber, liquefiable tar, gasification gas,
burnable gas, steam, water vapor, hydrogen, heat and
electricity.
[0016] In one embodiment of the invention, the gaseous product
fractions which are produced during the pyrolysis are condensed to
mainly liquid pyrolysis products. In one embodiment, most of the
energy and pyrolysis product fractions are circulated, recovered,
processed further and/or utilized.
[0017] Preferably, only part of the energy fractions that have been
formed in the combustion boiler are conducted to the pyrolysis
reactor and other process steps.
[0018] In one embodiment of the invention, a heat transfer material
is used for transferring the energy fraction, preferably heat, from
the combustion boiler to a desired process step, e.g. pyrolysis or
the desired and predefined additional steps and/or recovery. In one
embodiment, the heat transfer material is conducted separately to
each process step. In an alternative embodiment, the same heat
transfer material circulates through different steps. In one
embodiment of the invention, heat transfer material is circulated
from the combustion boiler to the pyrolysis reactor and from the
pyrolysis reactor back to the combustion boiler via a separation
step.
[0019] In one embodiment, the heat transfer material is selected
from the group comprising sand, bed sand, aluminum oxide based
material, other fluidization material and the like.
[0020] In one embodiment of the invention, the method comprises a
multistep pyrolysis in which fast pyrolysis is performed as a first
step and improved product fractions and/or additional product
fractions are formed as a second step by applying an additional
step.
[0021] In one embodiment of the invention, the method comprises a
multistep pyrolysis in which an additional step is performed as a
first step and fast pyrolysis is performed as a second step in
order to form improved product fractions and/or additional product
fractions.
[0022] In one embodiment, the additional step is selected from the
group comprising: drying, raising the temperature, gasification,
dust separation, reforming, steam reforming, separating the product
fractions and separating the solids. The separation of solids may
include separation of the heat transfer agent, such as sand, carbon
matter, coke, solid particles or equivalent solids.
[0023] In one embodiment, the first and the second step are
substantially integrated to one assembly, e.g. one device. In an
alternative embodiment, the devices of the first and the second
step are connected together.
[0024] In an alternative embodiment, the multistep pyrolysis may
include more than two steps.
[0025] In one embodiment of the invention, carrying out of the
pyrolysis step is modified in the method by at least one special
operation which is selected from the group comprising raising the
temperature, reducing the temperature, selecting the carrier gas,
feeding steam and adding oxygen.
[0026] In one embodiment, the pyrolysis gas that has been formed in
the first step is conducted to the second step in which the
temperature is substantially higher than in the pyrolysis step. If
water vapor is used as the carrier gas in this second step, a steam
reforming reaction occurs, resulting in a large proportion of the
tar compounds decomposing to hydrogen and carbon monoxide.
[0027] In one embodiment, the heat transfer agent is fed to the
reactor in two steps, to a drying step and to a reaction step. The
temperatures of the drying step and the reaction step are adjusted
separately for optimizing the product distribution and quality of
the product. In one embodiment, the raw material that has been fed
to the drying step and the heat transfer material are conducted as
a mixture to the second step, i.e. the reaction step, after
drying.
[0028] Any drying method known per se may be used as the drying
method, e.g. low temperature drying, drying by mixing or the like.
Part of the heat energy that has been formed in the combustion
boiler can be utilized for drying the fuel to be pyrolyzed. By
drying, the water content of the pyrolysis product that is being
formed is preferably reduced, whereby the stability of the product
increases. Water vapor can be recovered from the drying and be
utilized e.g. in heat production. In one embodiment, the vapor is
not separated from the drying step.
[0029] In one embodiment, the pyrolysis reactor is run as a
gasifier-type device. In this case, the temperature in the reactor
is higher than in the normal pyrolysis, and the gas yield is
maximized in the product distribution. In one embodiment, natural
gas is fed to the reactor as the additional material.
[0030] In one embodiment of the invention, the carrier gas is
selected from the group comprising combustion gas, preferably
purified combustion gas, water vapor, air and a mixture
thereof.
[0031] In one preferred embodiment of the invention, the carrier
gas contains oxygen. Preferably, the pyrolysis is performed in the
pyrolysis reactor in the presence of oxygen. In one embodiment,
carrier gas that contains oxygen in an amount of 1 to 7% by volume
is used. The preservability of the pyrolysis product can be
increased by the use of oxygen.
[0032] In one embodiment, additional oxygen is added to the carrier
gas e.g. in the form of air, to increase the oxygen content.
[0033] In one embodiment, purified combustion gas from the
combustion boiler is used as the carrier gas and circulated from
the combustion boiler to the pyrolysis reactor.
[0034] In one embodiment, water vapor is used as the carrier gas.
In this case, a steam reforming reaction occurs, resulting in a
large proportion of the tar compounds decomposing to hydrogen and
carbon monoxide.
[0035] In a preferred embodiment, the carrier gas is conducted once
through the pyrolysis reactor and conducted to the combustion
boiler. The carrier gas is not recirculated from the outlet of the
pyrolysis reactor to the inlet of pyrolysis reactor.
[0036] In one embodiment of the invention, the process parameters
are selected from the group comprising the temperature of the
pyrolysis step/temperature in the pyrolysis reactor, temperature of
the additional step, residence time in the pyrolysis reactor,
temperature of the combustion boiler, way of mixing and order of
mixing of the raw materials of the pyrolysis, carrier gas and heat
transfer material, addition of oxygen, circulation of the heat
transfer material and circulation of the product and side
fractions.
[0037] In one embodiment, the product fractions which are being
formed in the combustion boiler and pyrolysis reactor are divided
into products, side flows of the process, residual flows, waste
flows and/or unwanted fractions. In one embodiment of the
invention, most of the side, residual and waste flows, e.g.
residual flows from the condenser, residual flows from the
separating devices and filters, refuse flows of the raw materials,
combustion gas fraction and the equivalent flows, are substantially
circulated to the combustion boiler. Feeding the side, residual and
waste flows and the feed volumes thereof to the combustion boiler
do not have to be adjusted separately, due to the substantially
larger raw material feeding of the combustion boiler itself.
[0038] In one embodiment of the invention, the first raw material
and the carrier gas are arranged to a mixture and the heat transfer
material that has been heated is conducted to the mixture.
[0039] In one embodiment, suitable additional materials are used in
different steps of the process. E.g. alcohols, such as isopropanol,
ethanol or rapeseed oil methyl ester, can be used as additional
materials in conjunction with the condenser to improve the
operation of the condenser and/or quality of the product.
Alcohol-based materials can also be used in conjunction with
washers or the like to improve the operation of the device. In one
embodiment, catalysts can be used as additional material, e.g. in
the pyrolysis reactor or combustion boiler, e.g. in conjunction
with the sand circulation, to improve the efficiency of the process
and/or quality of the product.
[0040] Thanks to the invention, the efficiency, costs and product
distribution of the process can be optimized with respect to the
price of different products and product quality requirements. The
invention provides the advantage that the combination of the
pyrolysis and combustion according to the invention can be utilized
in the production of different and new products. Thanks to the
optimization method according to the invention, the pyrolysis
reactor may also serve at least partly other purposes than the
usual pyrolysis in terms of capacity and time. Furthermore,
different additional steps and devices can be readily combined with
the pyrolysis reactor in order to control the product distribution.
The integrated solution according to the invention provides a wider
operational framework for different ways of running and producing
different products.
[0041] The pyrolysis product and the energy fraction can both be
produced by the method according to the invention with higher
efficiency than what is known, because the side and waste flows
which are being produced, solid and carbon matter and
non-condensible gases and energy content thereof can be converted
in the combustion boiler to heat or steam for energy production.
Part of the heat energy of the combustion boiler is used in the
pyrolysis reactor, optionally for drying the pyrolyzed fuel and for
other additional process steps and for combustion of the
non-condensible gases in the combustion boiler, and most of the
heat energy is conducted to be recovered e.g. in the form of steam.
Additional feeding of energy is not required for the pyrolysis
reactor and for other process steps, because the heat energy
conducted from the combustion boiler is sufficient for maintaining
the process. The invention provides the advantage of achieving
self-sufficiency in terms of energy by the combination of the
pyrolysis reactor and the combustion boiler according to the
invention.
[0042] Feeding the optimal fuel mixtures to both pyrolysis reactor
and combustion boiler improves the efficiency of the process in
terms of yield of the pyrolysis product and heat energy and
minimizes the process costs.
[0043] The method according to the invention is easy to carry out
in the production. Thanks to the integrated combustion boiler,
energy is available and e.g. the temperature of the pyrolysis
reactor can be easily adjusted. The method according to the
invention can be applied for pyrolyzing a product utilized from any
suitable raw material. Furthermore, management of the process
according to the invention is easy. Coke and other equivalent
residual fractions do not accumulate in the process equipment but
can be instead conducted to the combustion boiler to be burned, so
that they do not cause any problems in the process. Therefore, the
possible coke content of the raw material does not have to be
concerned about when selecting the raw material.
[0044] A further advantage of the invention is that the coke
balance of the process and the heat balance of the drying do not
provide a restriction for the pyrolysis and other process
steps.
DETAILED DESCRIPTION OF THE INVENTION
[0045] In the following section, the invention will be described
with the aid of detailed exemplary embodiments.
Example 1
[0046] The process assembly according to the invention is formed,
comprising a combustion boiler, pyrolysis reactor and condensing
device. The pyrolysis reactor and the condensing device are
substantially integrated with the combustion boiler, i.e. a unified
assembly is formed. Fuel is fed to the combustion boiler and burned
for producing heat energy. In the pyrolysis reactor, gaseous
pyrolysis products are formed from suitable raw materials by
pyrolysis and condensed to liquid pyrolysis products in the
condensing device. Carrier gas is fed to the pyrolysis reactor. The
energy fractions in the form of heat, water vapor or gas, formed in
the combustion boiler, are recovered or part of the heat is
circulated to the other parts of the apparatus, such as to the
pyrolysis reactor, in the form of a hot heat transfer agent, which
in this embodiment is bed sand.
Example 2
[0047] The method of this example is carried out by the process
apparatus according to Example 1.
[0048] In the method, the most valuable and suitable part of the
raw material is used as the pyrolysis material and the less
suitable part in terms of pyrolysis is fed to the combustion
boiler. The raw material is divided in a manner known per se, e.g.
by a classifier or optical separator.
[0049] Good raw materials for the pyrolysis include residuals from
the forest industry, such as chips, saw dust and bark chips.
However, high liquid yield is only obtained for dry raw material
from the so-called heartwood without bark. In other words, a lesser
amount of the pyrolysis product is produced from the bark which is
furthermore more unstable and easily phase-separated. Therefore, it
is not advisable to feed the same raw material to the pyrolysis
reactor and the combustion boiler. A preferred embodiment is to
conduct bark containing raw material to the combustion boiler to
produce energy, and saw dust to the pyrolysis reactor to produce a
pyrolysis product. In addition, e.g. peat or coal is conducted to
the combustion boiler to satisfy the entire fuel need.
Example 3
[0050] The method of this example is carried out by the apparatus
according to Example 1. In this example, the processing includes
two steps, and the steps are combined together.
[0051] The pyrolysis gas that has been formed by pyrolysis in the
first pyrolysis step is conducted to the second process step in
which the temperature is substantially higher than in the pyrolysis
step. If water vapor is used as the carrier gas in this second
step, a steam reforming reaction occurs, resulting in a large
proportion of the tar compounds decomposing to hydrogen and carbon
monoxide. This method enables the production of gasifying gas e.g.
for the Fischer-Tropsch synthesis.
Example 4
[0052] The method of this example is carried out by the apparatus
according to Example 1.
[0053] Water vapor is used as the carrier gas in the pyrolysis. The
vapor may be obtained from the humidity of the raw material which
is separated e.g. during drying of the raw material. A steam
reforming reaction occurs. The product is a burnable gas or one
that can be processed further chemically, such as ammonia or a
synthetic fuel. The product gas may be used e.g. in the
Fischer-Tropsch synthesis. The humidity of the raw material can be
utilized as the steam in steam reforming.
Example 5
[0054] The method of this example is carried out by the apparatus
according to Example 1. In this example, the process includes two
steps and the drying and reaction processes are combined
together.
[0055] The heat transfer agent, which is bed sand, is fed in two
steps, the first part to the drying step and the second part to the
reaction step. The temperatures of the drying step and the reaction
step are adjusted separately for optimizing the product
distribution and quality of the product. Vapor is not separated
from the drying step but instead from the condensing of the product
gas.
Example 6
[0056] The method of this example is carried out by the apparatus
according to Example 1.
[0057] In this process, the raw material for the pyrolysis reactor
and the carrier gas which is a purified combustion gas are arranged
to a mixture and the hot bed sand particles from the combustion
boiler are conducted to the pyrolysis reactor to the mixture of the
raw material and the carrier gas. In this case, an area of heavy
turbulence is formed at the mixing point, i.e. a so-called flash
effect occurs, whereby the pyrolysis can be initiated rapidly and
efficiently. The applied sand, which in this embodiment has a grain
size of more than 0.5 mm, is substantially heavier than the raw
material of the pyrolysis and, therefore, acceleration of the sand
particles induces more efficient heat transfer and mixing of the
gases in the mixture flow, resulting in an enhanced pyrolysis.
Example 7
[0058] The method of this example is carried out by the apparatus
according to Example 1.
[0059] By increasing the proportion of air and thereby the oxygen
content in the carrier gas, the proportion of the liquefiable
components in the pyrolysis product, relative to the proportion of
the non-condensible fractions, can be varied according to the
desired product distribution. In this manner, the pyrolysis reactor
can be used as a gasifier-type device. The efficiency and heat
value provided by the combination of the pyrolysis and the
combustion boiler for the gas are higher than in the traditional
air gasification, because most of the heat can be introduced to the
gasification reaction by the circulating mass, i.e. the bed
sand.
Example 8
[0060] The method of this example is carried out by the apparatus
according to Example 1.
[0061] The product gas produced in the pyrolysis is heated to a
temperature above 1000.degree. C. to decompose the hydrocarbons. As
a result, hydrogen and carbon are produced as products in the form
of fine fibers. Due to their high strength, these carbon fibers can
be utilized as additional material e.g. in papermaking. The
advantage of the method is the inexpensive process for producing
carbon fibers, utilization of biomass in the production of carbon
fibers and easy way of producing hydrogen.
[0062] The method according to the invention is suitable in
different embodiments for producing different kinds of pyrolysis
products and derivatives thereof and for producing energy
fractions, such as heat energy.
[0063] The invention is not limited merely to the examples referred
to above; instead, many variations are possible within the scope of
the inventive idea defined by the claims.
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