JP2002153745A - Method for utilizing heat of combustion of biomass alcohol and system therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for utilizing heart of combustion of biomass alcohol, that is able to convert an energy of biomass alcohol to industrially available energy such as electric power and the like and that there is no need for the exhaust gas treatment, and to provide a system therefor. SOLUTION: The method comprises steps of fermenting biomass, concentrating biomass alcohol obtained by fermentation, feeding the resulting concentrated biomass alcohol to a reactor and feeding oxygen for combustion under pressure to the reactor, combusting the fed biomass alcohol in the reactor by the wet oxidation or the oxidation in an aqueous medium such as supercritical water and utilizing a heat energy in electric power by using a generated gas from the combustion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method and a system for utilizing the combustion heat of biomass alcohol produced by fermentation of biomass, a biological organic resource, and more particularly to the oxidation of biomass alcohol in an aqueous medium. The present invention relates to a method and system for using combustion heat for driving a steam turbine of a generator with high-temperature steam directly generated by a steam generator or for using a heat source for air conditioning or a factory.

[0002]

2. Description of the Related Art Biomass alcohols produced by fermenting carbohydrates of biomass, such as wood, agricultural crops, algae, plankton, and biological waste, can be produced in large quantities and are also advantageous for environmental problems. As a result, various efforts have been made to expand the range of use for industries other than beverages.

[0003] However, the alcohol obtained by biomass fermentation is mainly ethanol, but the concentration is very low, about 1%, 2% to 10%, so that it is necessary to further concentrate it for industrial use. There is. for that reason,
Attempts have been made to obtain high concentrations of alcohol by employing a distillation process.

[0004] In this distillation step, a large amount of energy is consumed and the production cost is increased. Therefore, in Japanese Patent Application Laid-Open No. 2-26953, molasses is used as a raw material for fermentation and distillation. Ethyl alcohol production method in which the discharged waste liquid is concentrated in a vapor compression evaporator, and the concentrated liquid is burned in a boiler to obtain heated steam, thereby driving a turbine to generate necessary electricity in a factory. Proposed.

[0005]

However, in this method for producing ethyl alcohol, even if power is generated by a boiler using distillation waste liquid as a fuel and the required electric power is obtained, a self vapor compression evaporator for condensing the waste liquid, A waste liquid boiler equipped with a special waste liquid burner or the like is required, and there is a problem that the apparatus becomes complicated and the production cost increases.

In recent years, the distillation technology has been advanced by using a combination of extractive distillation and vacuum distillation, a heat pump, a multi-effect distillation method, and the like, and high efficiency and energy saving have been promoted. However, there is still a problem that the cost of concentrating fermented alcohol is high in the field of use.

[0007] It is more energy-saving than distillation technology,
Even in the pervaporation technology, which is considered to be able to efficiently produce alcohol from biomass, practical use has not progressed because of the difficulty in alcohol permeation performance.

Therefore, when producing fermented alcohol from biomass, if it is attempted to use it after concentrating it to a high concentration, the energy required for the concentration will increase as long as a single operation of the prior art is used, and the production energy will increase. There is a problem that the use is limited because the cost is high.

[0009] For this reason, biomass alcohol has a limited use as compared with synthetic alcohol, and is mainly used for beverages such as distilled liquor, and is used very little in industrial use.

The present invention has been made in order to solve the above-mentioned problems, and an object of the present invention is to convert the energy of biomass alcohol into energy such as electric power that can be used industrially, and furthermore, the necessity of exhaust gas treatment. It is an object of the present invention to provide a biomass alcohol combustion heat utilization method and a system therefor which do not have any problem.

[0011]

The method of utilizing biomass alcohol combustion heat of the present invention is configured as follows.

1) A step of fermenting biomass, a step of concentrating biomass alcohol obtained by fermentation, and supplying the concentrated biomass alcohol to a reactor, and pressurizing the reactor with oxygen for combustion. And burning the supplied biomass alcohol in the reaction apparatus by wet oxidation or oxidation in an aqueous medium such as supercritical water, and using a gas such as steam generated by the combustion. And a step of utilizing heat such as power generation.

This biomass alcohol is concentrated to a few percent immediately after fermentation, and is concentrated. In order to reduce the energy required for the concentration, the concentration is reduced to about 10 to 80% (preferably 15 to 30%). It is concentrated and then wet oxidized, or oxidized in an aqueous medium such as supercritical water.

The oxygen for combustion may be supplied by pressurizing the air as it is, but it is more efficient to supply the oxygen at a high oxygen concentration. Preferably, it is used to supply high purity oxygen.

According to this configuration, the biomass alcohol, which is one of the biomass fuels, is concentrated, oxidized and burned in an aqueous medium such as wet oxidation or supercritical water, and directly generates high-temperature steam. Can be efficiently converted to steam energy, and the high-temperature steam drives a steam turbine, or is used as a heat source for air conditioning or a factory.

Further, since the biomass alcohol is subjected to wet oxidation at a high temperature and pressure close to the critical state in a state where the concentration of the biomass alcohol is relatively low, or to oxidize in the supercritical water state, the equipment and energy required for the concentration are reduced, and the profit is reduced Good nature.

2) In the method of utilizing biomass alcohol combustion heat, when the concentrated biomass alcohol is supplied to the reactor, the biomass alcohol may be supplied at the same temperature. 350
It is preferable to supply the mixture by heating to a temperature of ° C.

This is because the heating can promote the combustion reaction in the reactor.

Further, if the heat required for this heating is covered by a part of the heat generated in the reactor, the generated heat can be used efficiently and the thermal efficiency of the whole system is improved.

3) In the above-mentioned method of utilizing biomass alcohol combustion heat, the oxygen concentration for supplying pressurized oxygen to the reaction apparatus is set to 20% to 100% before supply.

This oxygen may be supplied by pressurizing the air itself, but preferably, high-concentration oxygen obtained from a commercially available oxygen generator or the like is supplied to exclude components not directly related to the reaction. As a result, the reactivity can be increased, the component ratio of water vapor in the generated gas can be increased, and the power generation efficiency of the steam turbine can be improved.

[0022] 4) Further, in the biomass alcohol combustion heat utilization method, in the reactor, at a temperature in the range of 0.99 ° C. to 650 ° C. The oxidation in aqueous medium, and, 5
MPa-60MPa, preferably 5-30MPa
The pressure range is as follows.

With this temperature range and pressure range, a good balance between the reactivity and the heat resistance and pressure resistance of the reactor can be maintained, and power can be efficiently generated.

The biomass alcohol combustion heat utilization system for carrying out the above biomass alcohol combustion heat utilization method is configured as follows.

5) A biomass alcohol supply device for concentrating and supplying biomass alcohol obtained by fermenting biomass, a reaction device for burning the biomass alcohol by oxidation in an aqueous medium, and a combustion device for the combustion device. It is configured to include an oxygen supply device that pressurizes and supplies oxygen and a heat utilization device that uses heat of a gas such as steam generated in the reaction device for power generation or the like.

With this configuration, with a simple system configuration,
Power can be efficiently generated using biomass alcohol as fuel.

6) In the biomass alcohol combustion heat utilization system, the biomass alcohol supply device includes a concentrating device for concentrating the biomass alcohol and a heating device for heating the biomass alcohol. As this heating device, a pump for pressurizing and feeding the biomass alcohol concentrate can be used instead.

According to this configuration, the reactivity by wet oxidation is enhanced, and power can be generated more efficiently.

7) Further, in the above biomass alcohol combustion heat utilization system, the heating device is formed by a heat exchanger that heats the biomass alcohol using heat generated in the reaction device.

According to this configuration, the heat generated in the reactor can be used efficiently.

[0031]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a biomass alcohol combustion heat utilization system according to the present invention will be described with reference to the drawings.

In this embodiment, a biomass alcohol combustion heat utilization system will be described using an example of a biomass alcohol power generation system using generated gas for driving the turbine. The oxidation method in an aqueous medium will be described by taking wet oxidation as an example. Therefore, the heating temperature or the combustion temperature is 150 ° C. to 350 ° C., which is lower than 150 ° C. to 650 ° C., and the pressure is 5 MPa, which is lower than 5 MPa to 60 MPa.
a to 30 MPa.

FIG. 1 illustrates a configuration diagram of a biomass alcohol power generation system 1 according to the present invention.

This biomass alcohol power generation system 1
Is a biomass alcohol supply device 10 for supplying biomass alcohol E concentrated from a biomass alcohol solution A fermented in a fermenter 11 or the like, a reaction device 20 for reacting the supplied biomass alcohol E, and a reaction device 20 for combustion. An oxygen supply device 30 that pressurizes and supplies oxygen O _{2 of this type} and a power generation device (heat utilization device) 40 that generates power using generated gas G generated by combustion of the reaction device 20 by wet oxidation. You.

The biomass alcohol supply device 10 includes a fermenter 11 for fermenting biomass such as wood and agricultural crops as biological organic resources, a concentrator 12 for increasing the concentration of fermented biomass alcohol A, and a concentrator 12. Storage tank 13 for storing biomass alcohol E
And a transfer pump 14 for transferring the biomass alcohol E from the storage tank 13 to the reactor 20 and a heat exchanger 15 for heating and raising the temperature of the biomass alcohol E entering the reactor 20.

The heat source of the heat exchanger 15 includes a reaction
It is efficient to use a part of the heat generated in the device 20.
Therefore, the gas generated from the reactor 20 (the main component is carbon dioxide)
CO _Two And steam H_Two O) Adjusting valve for G to heat exchanger 15
Circulate via 16.

Next, the reactor 20 is set at 150 ° C. to 350 ° C.
A reaction vessel 21 for performing wet oxidation at a high temperature and high pressure of about 5 to 30 MPa at about
Is an oxygen generator 31 that generates high-concentration (90 to 99.9%) oxygen, and a reactor 2 that pressurizes this high-concentration oxygen.
And a compressor 32 for supplying 0.

The power generator 40 includes a steam turbine 41 driven by a generated gas G mainly composed of water vapor generated in the reactor 20, and a generator 42 driven by the steam turbine 41.

Further, the water vapor H ₂ in the generated gas G
The condenser 51 for condensing O and the condenser 51
And a separator 52 for separating water H ₂ O in the generated gas G that has passed through the power generation device 40, and is provided with an exhaust gas cooling device 50 for cooling the generated gas G coming out of the power generation device 40.

Next, power generation in the biomass alcohol power generation system 1 will be described.

[0041] Wood, agricultural, algae, plankton, ground carbohydrates organisms waste, sterilization, aging, the pre-treatment sterilization or the like, placed in a fermentation tank 11, and fermented by yeast or the like, several% A concentrated biomass alcohol solution A is generated. The alcohol solution (mostly ethanol C ₂ H ₅ OH) A obtained from this fermentation is separated from the treatment aqueous solution B by a concentrating device 12 such as a membrane separation device to extract the produced alcohol E. It is concentrated back and forth and stored in the storage tank 13.

As the membrane separator 12, a membrane distillation separator, a pervaporation membrane separator, a reverse osmosis membrane separator, or the like can be used. In particular, a membrane distillation separator using an alcohol selectively permeable membrane, It is desirable to use a pervaporation membrane device, and this concentration can be performed at around normal temperature. The aqueous solution B treated by the membrane separation device 12 can be subjected to a dealcoholation treatment to several thousand ppm or less. The aqueous solution B can be returned to the fermenter 11 and used for diluting the fermented solution. Thereby, the fermentation efficiency of yeast can be improved.

This ethanol E is pumped by the transfer pump 14 and put into the reaction tank 21 of the reactor 20 via the heat exchanger 15. The heat exchanger 15 uses a part of the heat generated in the reaction tank 22 to heat the biomass alcohol E,
The temperature is raised to about 0 ° C. to 350 ° C., preferably about 200 ° C. This biomass alcohol E concentrated to 15% or more has a property of spontaneously burning when the temperature is 200 ° C. or more and oxygen is present.

On the other hand, oxygen O ₂ pressurized by the compressor 32 of the oxygen supply device 30 is injected into the reaction tank 21, and the inside of the reaction tank 21 is set to a high pressure of 5 MPa to 30 MPa to perform wet oxidation. This oxygen can be separated from oxygen in the air in a high concentration (90 to 90%) by using a gas separation membrane, using a cryogenic separation method, or using a known method such as a PSA (PRESURE SWING ADSORPTION) method. (99.9%) oxygen.

Then, ethanol E obtained by this wet oxidation is used.
The high temperature gas G generated by the combustion of
To the steam turbine 41 to drive the generator 42 to generate power.

The generated gas G after driving the steam turbine 41 is cooled by a condenser 51 cooled by cooling water W to become condensed water H ₂ O. The generated gas G passing through the condenser 51 is separated by a separator 52. Further, the condensed water H ₂ O is discharged after being separated. However, since carbon dioxide CO ₂ is almost contained and contains no harmful components, exhaust gas treatment is unnecessary.

Next, a description will be given of the result of a trial calculation regarding the energy relation assuming that the biomass alcohol is ethanol.

Q0 in the figure is a biomass alcohol solution A
Energy for concentrating the biomass alcohol E (0.1 MPa, 25 ° C.), and Q2 heating the biomass alcohol E (25 ° C.) to 200 ° C. in the heat exchanger 15. Q3 is the heat energy for radiating heat from the reaction tank 21, Q4 is the energy required for oxygen supply,
Numeral 5 indicates the amount of heat generated in the reaction tank 2, Q6 indicates energy which can be used by power generation, and Q7 indicates energy which is condensed with steam and becomes cooling water.

The concentration energy Q0 of the membrane separation from the 5 wt% biomass alcohol solution A to the 5-20 wt% biomass alcohol E is increased to 2,000 kJ / k.
g, and Q1 is assumed to be slight and is ignored. Also, Q2
, The heat conversion efficiency of the heat exchanger 22 is 90%,
Regarding Q3, the heat radiation is 5%.

Regarding Q4, the process of compressing oxygen is performed by polytropic compression, and is performed in four stages from 0.1 MPa to 5 MPa or 10 MPa.
To 15 MPa or 20 MPa, it is performed in five stages, and the polytropic index k is set to 1.3. In addition, the enrichment energy of oxygen by cryogenic separation is 24,200 kJ /
Calculate as kmol.

The calorific value Q5 in the reaction tank 21 is determined by the concentration of ethanol and the calorific value (1,36
8 kJ / kmol), and regarding the power generation energy Q6, the thermoelectric conversion efficiency ηQ of the power generation device 40 is 60 to 90.
%.

According to this calculation, the energy Q4 required to supply the amount of oxygen necessary for combustion is such that oxygen concentrated to 99.9% is supplied under pressure rather than pressurized supply of air having an oxygen concentration of 21%. Energy saving of 50% or more.

It was also found that the amount of increase in the oxygen supply energy Q4 with respect to the increase in the pressure of the reaction tank 12 was relatively small, and that the operating pressure of the reaction tank 12 had no significant effect in the estimated calculation range of 5 MPa to 20 MPa.

When the amount of power recovery is estimated on the basis of the above, power can be recovered at an ethanol concentration of 10% by weight or more in a calculation range of 5 MPa to 20 MPa.

In a trial calculation example in the case where a 20 wt% low concentration ethanol solution was wet-oxidized at an operating pressure of 20 MPa,
It is found that the thermoelectric conversion efficiency ηQ is 80% and the power generation efficiency is about 24%.

According to the biomass alcohol power generation system 1 having the above configuration, the following effects can be obtained.

According to this system, even a low-concentration alcohol solution of about 10 to 30% can be burned by wet oxidation operated below the supercritical point, and directly generates high-temperature steam. Good thermal efficiency.

Further, high-temperature steam is directly generated by bio-oxidation of biomass alcohol, which is one of the biomass fuels, and the high-temperature steam drives the steam turbine of the power generator. In addition, since wet oxidation can be performed even in a state where the concentration of biomass alcohol is low and about 10 to 30%, the amount of equipment and energy required for concentration is small, and profitability is good.

When supplying the biomass alcohol to the reactor, the biomass alcohol is supplied at 30 ° C. to 35 ° C.
By heating to 0 ° C., the heat generated in the reactor can be used efficiently, and the thermal efficiency of the entire system can be improved.

When oxygen for combustion is supplied under pressure to the reactor, the concentration of oxygen is adjusted to 90% to 99.9%.
By supplying high-concentration oxygen, components that are not directly related to the reaction can be excluded, thereby increasing the reactivity, increasing the component ratio of water vapor in the generated gas, and improving the efficiency of the steam turbine.

Further, in the reactor, the oxidation in the aqueous medium is carried out at a temperature in the range of 150 ° C. to 350 ° C. and 5 MPa to 5 MPa.
By performing the reaction in a pressure range of 30 MPa, the power generation can be efficiently performed while maintaining a good balance between the reactivity and the heat resistance and pressure resistance of the reactor.

Further, since alcohol is burned, the components of the exhaust gas become carbon dioxide and moisture, and no harmful components are contained in the exhaust gas. Therefore, there is no need to perform exhaust gas treatment, and the system configuration is simplified.

In the above-described embodiment, the wet oxidation has been described as an example of the oxidation method, and the power generation by the steam turbine has been described as an example of the heat utilization method. However, the present invention is not limited to this combination of wet oxidation and power generation.

[0064]

As is apparent from the above description, the method and system for utilizing biomass alcohol combustion heat according to the present invention can provide the following effects.

High-temperature steam is directly generated by bio-oxidation of biomass alcohol, which is one of the biomass fuels, by wet oxidation or wet oxidation or in an aqueous medium such as supercritical water. Is driven or used as a heat source in factories and the like, so that the thermal efficiency is high. In addition, since the biomass alcohol can be oxidized in an aqueous medium even in a state where the concentration of biomass alcohol is low and about 10 to 30%, less equipment and energy are required for concentration, and profitability is good.

When supplying the biomass alcohol to the reactor, the biomass alcohol is supplied at 30 ° C. to 35 ° C.
By heating to 0 ° C., the heat generated in the reactor can be used efficiently, and the thermal efficiency of the entire system can be improved.

Then, when pressurizing and supplying oxygen for combustion to the reactor, oxygen is added in an amount of 20% to 100%, preferably 9%.
By supplying a high concentration of oxygen at a concentration of 9% to 100%, components not directly related to the reaction are excluded, thereby increasing the reactivity and increasing the component ratio of steam in the generated gas. Efficiency can be improved.

Further, in the reaction apparatus, the oxidation in the aqueous medium is carried out in a temperature range of 150 ° C. to 650 ° C. and 5 MPa to 5 MPa.
By performing the reaction in a pressure range of 60 MPa, the balance between the reactivity and the heat resistance and pressure resistance of the reactor can be maintained well, and heat can be efficiently used for power generation and the like.

Further, since the combustion of alcohol is performed, the components of the exhaust gas are carbon dioxide and moisture, and no harmful components are contained in the exhaust gas. Therefore, there is no need to perform exhaust gas treatment, and the system configuration is simplified.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of a biomass alcohol power generation system according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Biomass alcohol power generation system 10 Biomass alcohol supply apparatus 11 Fermenter 12 Concentrator 13 Storage tank 15 Heat exchanger 20 Reactor 21 Reactor 30 Oxygen supply apparatus 31 Oxygen generator 32 Compressor 40 Generator 41 Steam turbine 42 Generator 50 Exhaust gas Cooling device A Biomass alcohol solution E Biomass alcohol G Generated gas

 ──────────────────────────────────────────────────続 き Continuation of the front page (71) Applicant 500527845 Hiroshi Yanagishita 2-711-701, Azuma, Tsukuba-shi, Ibaraki (71) Applicant 599169900 Dai Kitamoto 3-3-206-103 Takezono, Tsukuba-shi, Ibaraki (74) 4 above Name agent 100066865 Patent Attorney Shinichi Ogawa (2 other) (72) Inventor Takashi Nakane 1-1-1 Higashi, Tsukuba, Ibaraki Pref. 1-1, 1st, National Institute of Advanced Industrial Science and Technology (72) Inventor: Dai Kitamoto 1-1-1, Higashi, Tsukuba-shi, Ibaraki Pref., Institute for Material Engineering, National Institute of Advanced Industrial Science and Technology (72) Inventor: Masakazu Kondo Tama3, Tamano-shi, Okayama No. 1-1, Mitsui Engineering & Shipbuilding Co., Ltd. Tamano Works F-term (reference) 3K065 TA00 TB07 TB15 TC10 TD04 TE06 TF04 4B064 AC03 CA06 CD24 CD25 CE01 CE0 8 DA20

Claims (7)

[Claims] 1. A step of fermenting biomass, a step of concentrating biomass alcohol obtained by fermentation, supplying the concentrated biomass alcohol to a reactor, and pressurizing the reactor with oxygen for combustion. And burning the supplied biomass alcohol in the reaction apparatus by wet oxidation or oxidation in an aqueous medium such as supercritical water, and using a gas such as steam generated by the combustion. Using biomass alcohol combustion heat. 2. The method for utilizing biomass alcohol combustion heat according to claim 1, wherein the biomass alcohol is heated to 30 to 350 ° C. when the concentrated biomass alcohol is supplied to the reactor. 3. The biomass alcohol combustion according to claim 1, wherein the oxygen concentration of the gas is set to 20% to 100% when the oxygen for combustion is supplied to the reactor under pressure. Heat utilization method. 4. The method according to claim 1, wherein the oxidation in the aqueous medium is performed in a temperature range of 150 ° C. to 650 ° C. and 5 MPa to 5 MPa.
The method for utilizing biomass alcohol combustion heat according to any one of claims 1 to 3, wherein the method is performed in a pressure range of 60 MPa. 5. A biomass alcohol supply device for concentrating and supplying biomass alcohol obtained by fermenting biomass, a reaction device for burning the biomass alcohol by oxidation in an aqueous medium, and a combustion device for the combustion device. Biomass alcohol combustion characterized by comprising an oxygen supply device for supplying oxygen by pressurization and a heat utilization device for utilizing heat of a gas such as water vapor generated in the reaction device for power generation or the like. Heat utilization system. 6. The biomass alcohol combustion heat utilization system according to claim 5, wherein the biomass alcohol supply device includes a concentrating device for concentrating the biomass alcohol, and a heating device for heating the biomass alcohol. 7. The biomass alcohol combustion heat utilization system according to claim 6, wherein the heating device is formed by a heat exchanger that heats biomass alcohol using heat generated in the reaction device.