JP2005288320A - Method and apparatus for energy recovery of high moisture biomass - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and apparatus for energy recovery of high moisture biomass having a quick processing speed. <P>SOLUTION: The high moisture biomass 1 is allowed to enter an airtight adiabatic vessel 11 and moisture of the biomass 1 is continuously vaporized and sucked from the inside of the vessel 11 by a water vapor compressor 12. The vaporized moisture is adiabatically compressed by the compressor 12, thereby, pressure and temperature of the vaporized moisture is elevated and the pressure-elevated steam is allowed to pass through a steam condenser 13 that is thermally connected to the inside of the vessel 11. Heat exchange is performed between the pressure-elevated steam and the biomass 1 and the moisture in the vessel 11 is vaporized. At the same time, the pressure-elevated steam releases condensation latent heat by itself, turns to distilled water 4 and is discharged from the condenser 13. Thus, the biomass 1 is separated into a low moisture biomass fuel 33 and distilled water 4. The biomass fuel 33 is taken out of the vessel 11 and is transduced into motive power (energy) 6 by a power generator 5 and meanwhile, the distilled water 4 is used as water for the power generator 5. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method and an apparatus for recovering energy of a high water content biomass, and more particularly to a method and a device for recovering energy from the fuel and distilled water after dividing the high water content biomass into biomass fuel and distilled water.

  Biomass is an organic substance that composes organisms that store solar energy through photosynthesis, and its form varies from solid fuels such as firewood to garbage and fluid waste such as sewage sludge.・ Various types such as plants. The present biomass abundance on the earth is about 2 trillion tons, which is considered to be comparable to the reserves of oil and coal, and about 200 billion tons are regenerated every year by photosynthesis.

The amount of biomass used in Japan is far less than fossil fuels such as oil and coal. However, as the finite nature of fossil fuels is recognized, attention is focused on its importance as an alternative energy. In addition, even if carbon dioxide (C0 ₂ ) is once released into the atmosphere by combustion, if the same amount of biomass is regenerated, the regenerated biomass absorbs and fixes the same amount of C0 ₂ in the atmosphere. It has the characteristic of not causing atmospheric carbon contamination (carbon neutral characteristic). For this reason, biomass is positioned as an important energy source that does not cause atmospheric carbon contamination in global warming countermeasures. Conventional technologies for extracting energy from biomass can be arranged as shown in the following (a) to (c) including those in the research and development stage.

(A) Direct combustion In this method, for example, biomass is directly burned in a boiler to generate water vapor, and a steam turbine and a generator are driven to generate power. As shown in FIG. 9, Non-Patent Document 1 showing an example of energy recovery by direct combustion directly burns biomass such as sawdust 40a and barkyard (bark) 40b in a boiler 41, and passes through a steam turbine 42. Disclose power generation equipment that drives a generator 37 with an output of 5.7 MW and includes a factory drying equipment 43, an air-cooled condenser 44, a water tower 45, a feed water heater 46 to the boiler 41, a pure water device 52, etc. Yes. However, this power generation facility uses biomass (sawdust 40a, bark 40b, etc.) provided to ensure the diversity of heating fuel, and it is difficult to collect fuel to increase output to reduce power generation costs. It is said that there is.

(B) Thermochemical conversion In this method, solid biomass is converted into gas fuel, liquid fuel, or biodiesel fuel by thermal decomposition or supercritical hydrothermal decomposition. The amount of dioxins generated during thermochemical conversion of biomass is small, and the choice of power generation methods is expanded by gasification and liquefaction. In addition to steam turbine drive power generation, gas engines, diesel engines, gas turbines, Stirling engines, fuel cells, etc. Becomes available. Non-Patent Document 2, as shown in FIG. 10, discloses a STAR-MEET system for waste pyrolysis gasification, which is an example of thermochemical conversion of biomass. In the illustrated example, the waste 40c is charged into the pyrolysis gasification furnace 38 of the pyrolysis gasification / reformer 30 and gasified by pyrolysis at a relatively low temperature.

In the method of FIG. 10, the pyrolysis gas contains flammable gases such as CO (carbon monoxide) and H ₂ (hydrogen) in addition to flammable components such as tar and soot. Since it solidifies, it is difficult to cool and clean the pyrolysis gas as it is. Therefore, by introducing the pyrolysis gas to the reformer 39 and reacting with water vapor, tar and soot are reformed to CO and H ₂ by the following reaction. However, these reactions require a high temperature of about 800 ° C. or higher, and a reforming reaction cannot be caused only by injection of water vapor at 100 ° C. Therefore, a mixed gas of water vapor and oxygen or air is sent from the high-temperature steam / air heater 48 to the reformer 39, and heat energy necessary for reforming these exothermic reactions is supplied.

C + CO ₂ → 2CO ………………………………………………………………… (1)
C + H ₂ O → CO + H ₂ ……………………………………………………………… (2)
C _n H _m + nH ₂ O → nCO + (n + m / 2) H ₂ …………………………………………… (3)
C + O ₂ → CO ₂ …………………………………………………………………… (4)
C + (1/2) O ₂ → CO …………………………………………………………… (5)

  In FIG. 10, the reformed gas is once cooled through a waste heat recovery boiler 49, and then environmental pollutants such as sulfur, chlorine, dust, and heavy metals are removed by a gas scrubber 50 to obtain a refined fuel gas 51. The fuel gas 51 can be used for various purposes such as process heating and power generation including industrial furnaces, boilers, or internal combustion engines (heat engines) 53 (diesel engines, gas engines, gas turbines, etc.). The steam generated in the waste heat recovery boiler 49 is sent to a high-temperature steam / air heater 48, mixed with air and heated to 1,000 ° C for reforming reaction, and also used for pre-drying waste. it can.

(C) Biochemical conversion For example, it is a method of converting biomass into gas fuel by methane fermentation, ethanol fermentation or hydrogen fermentation, and the same effect as thermochemical conversion is obtained. In the methane fermentation system of Patent Document 1 showing an example of energy recovery by biochemical conversion, raw garbage is cut into granules and made into a slurry, which is further pulverized by a pulverizer. An anaerobic treatment tank having an inlet for slurry from the fine pulverizer, an outlet for digestive juice, and a heater and having anaerobic microorganisms inside is provided, and the pulverized raw garbage is anaerobically treated by the treatment tank. . In addition, a gas holder that communicates with the upper space in the anaerobic treatment tank and the heater is installed to collect methane gas or other combustible gas generated by the garbage slurry decomposition reaction by microorganisms, and convert the combustible gas into electric power by power generation means. To do. This system improves the garbage decomposition efficiency of the anaerobic treatment tank by the fine pulverization and increases the output of the power generation means by using a high-efficiency fuel cell, etc. The driving force of the crusher and the transfer power of the slurry, digestive fluid, product gas, etc. can be covered by the output of the power generation means. Furthermore, there is a possibility of supplying surplus power to the outside.

  In applying the biomass energy recovery technology described above, it is necessary to pay attention to the moisture content of the recovery target biomass. In other words, the biomass is low in moisture, typically woody, and close to dry matter (hereinafter referred to as low-moisture biomass), and biomass that contains a large amount of moisture such as food waste, sewage sludge, and livestock manure (hereinafter referred to as “biomass”). Called high-moisture biomass). The classification of low water content and high water content is not clear, but from the viewpoint of suitability for combustion, as a guideline, the water content (ratio of water mass to total biomass mass (water mass + dry mass)) is about 30%. Less than can be handled as low water content, and 30 to 40% or more can be handled as high water content.

  Low water-containing biomass can be used as appropriate for both thermochemical conversion and biochemical conversion in addition to conventional steam turbine power generation by direct combustion. On the other hand, the main application technology for high water content biomass is currently only biochemical conversion such as methane fermentation. Supercritical hydrothermal decomposition aims to overcome this limitation of high water content biomass, but is still in the basic research stage. In short, as shown in FIG. 11, in the low water content biomass 3, the steam turbine driven power generation / heat utilization 55 through the combustion (boiler) 41, and in the high water content biomass 1, the biogas driven power generation through the methane fermentation (device) 36. -Heat utilization 56 is a typical technology, and the low water content biomass 3 and the high water content biomass 1 are completely different energy conversion methods. For this reason, it is difficult to treat various types of biomass over a wide range regardless of the water content, using a single facility, which is an obstacle to the widespread use of biomass energy.

Hiroshi Watanabe “Profitability of Power Generation / Heat Supply Business Using Forest / Wooden Biomass and Future Market Outlook” Characteristics of Biomass Energy and Energy Conversion and Utilization Technology (Lecture 5), Technical Information Center, Inc., April 30, 2002 Issued daily, p157 Kunio Yoshikawa “Possibility of high-efficiency waste power generation using micro gas turbines” Development trend and future prospects of micro gas turbines (Lecture 3), Technical Information Center, Inc., January 31, 2001, p64 Toshiyuki Hino “Energy Saving Evaporative Dehydration Technology Using Steam Heat Pump”, Proc. 17th Energy System / Economic / Environmental Conference, Jan. 25-26, 2001, pp. 691-696 Japanese Patent No. 3159300 Japanese Patent No. 3147142 JP-A-11-257622 JP 2001-116457 A

  However, the conventional energy conversion by methane fermentation of high water content biomass has a problem that the processing speed is slow. The average residence time in the fermenter required for methane fermentation is 20 to 30 days for the medium temperature method (30 to 37 ° C), and 7 days or more for the high temperature method (50 to 57 ° C) (see Patent Document 1, paragraph 0014). . For example, in order to process daily garbage at this speed, a large reaction container (anaerobic treatment tank) is required, which increases equipment costs.

  In addition, for methane fermentation of high water content biomass, the energy conversion rate to methane varies depending on the type of biomass, and it is high for garbage etc., but low for livestock manure and fiber, etc., and fats and oils are not suitable for this type of conversion. There are also problems. The average energy conversion rate for all types of biomass treated as high water content biomass is about 50% with currently available technologies, and there is still room for improvement in terms of energy conversion rate related to the cost of recovered energy. I must. In addition, there are problems such as a large amount of energy consumption of incidental facilities such as pumps and heating devices, and treatment of fermentation effluent (digested liquid) and residue (digested sludge).

  Some of these problems can be expected to be improved by research and development, but biochemical treatment inherently has reaction rate limitations. The suitability for methane fermentation varies depending on the composition of whether the biomass is woody or garbage or other non-woody material, so it is also necessary to determine appropriateness and classify in advance. Furthermore, in the prior art, as shown in FIG. 11, depending on the water content of the energy recovery target biomass, an energy conversion method using methane fermentation 36 is used in the case of the high water content biomass 1, and methane is used in the case of the low water content biomass 3. There is a problem that two systems are required because the two-system system is used as a completely different system other than fermentation 36.

  Accordingly, an object of the present invention is to provide a method and an apparatus for recovering energy of high water content biomass having a high processing speed.

  The inventor paid attention to energy saving and speeding up of the dehydration treatment of the high water content biomass 1. If the high water content biomass 1 can be efficiently dehydrated in a short time to make the low water content biomass 3, the relatively fast energy recovery of the low water content biomass 3 can be integrated with the energy recovery of the high water content biomass 1 and can be easily used. It should be.

  Patent Document 2 discloses the operating principle of a steam heat pump dehydration (SHPD) technique that efficiently and rapidly dehydrates the high water content biomass 1. Non-Patent Document 3 uses a steam heat pump dehydration (hereinafter sometimes referred to as SHPD drying) device to dehydrate the sample of 501.95 kg containing about 9 times the moisture of the anhydrous material component of shochu for about 6 hours. Describes the experimental results of treatment and reducing its moisture to about 13% (0.13 times) the anhydrous material. The amount of water vapor evaporated by this dehydration is 445.1 kg. The coefficient of performance (COP) is calculated from the heat of vaporization 1.0235GJ (284.3kWh) of the water vapor amount and the compressor power 39.3kWh of the water vapor heat pump required for evaporation. Calculated as 7.23. This means that the dehydration of the shochu can be achieved not by supplying the amount of heat corresponding to the latent heat of vaporization of water but by the compressor work corresponding to about 1/7 of the latent heat of vaporization using a heat pump. That is, according to SHPD drying, the high water content biomass 1 can be dehydrated quickly and efficiently.

  For example, the methane fermentation of Patent Document 1 describes that a fermenter residence time of 7 days or longer was required to convert the high water content biomass of garbage into fuel gas for fuel cells. Although it is unreasonable to directly compare the length of conversion time from high water content biomass to fuel gas and the length of dehydration time of high water content biomass, the present inventor paid attention to the drying speed of the SHPD drying device. If it can be dried quickly, it is possible to prevent an increase in the size of the drying equipment, and thus to reduce the cost of recovering energy from biomass.

  Furthermore, the present inventor paid attention to the fact that the condensed water discharged from the SHPD drying apparatus is substantially distilled water and does not contain a mineral component, so that it has high industrial usefulness. Although conventional biomass energy recovery methods certainly extract energy from organism-derived biomass-constituting organic matter, the moisture contained in the biomass is subject to various treatments during the energy extraction process and is dissipated into the environment without considering reuse. Or are subject to wastewater treatment. For example, Patent Document 3 discloses a method of drying a waste material having a high water content to lower the water content and then supplying the waste to a pyrolysis furnace. Is dissipated. On the other hand, there are many examples of power generation and other energy generation processes that require high-purity water. For example, the biomass power generation facility and the pyrolysis gasification facility described in Non-Patent Documents 1 and 2 require water for boilers or pure water such as distilled water as a reforming reaction material.

  The condensed water of the SHPD drying apparatus is distilled water which is obtained by condensing the moisture of the high water-containing biomass once after evaporation, and is high in temperature and free of minerals. Ordinary water contains minerals such as calcium ions and magnesium ions. For this reason, when normal water is used for boiler water, minerals are concentrated due to the generation of water vapor, generating scales (scale stones) on the inner surface of the boiler, impeding heat transfer, and in some cases may result in damage to the boiler. is there. In order to prevent this, a pure water production apparatus using a reverse osmosis membrane or an ion exchange resin is used. If distilled water obtained from the SHPD drying apparatus is used, such a pure water production apparatus can be dispensed with or its operating cost can be greatly reduced. The use of this distilled water as water for power generation facilities or pyrolysis gasification facilities means that these facilities produce pure water equivalent to distilled water that is produced by pure water equipment or products of SHPD drying equipment. It means to replace with, and has important resources and economic significance such as reduction of operation cost.

  Depending on the type of high-moisture biomass, volatile organic substances may be contained in distilled water from the SHPD dryer, but there are many cases where this is practical, and if necessary, underwater oxidation treatment, adsorption, etc. Can be easily removed. In terms of quantity, there is no problem because the amount of distilled water from the high water content biomass is sufficiently larger than the amount of pure water used (about the amount of distilled water). Moreover, it is desirable from the viewpoint of reducing the environmental load to reuse the moisture contained in the biomass without dissipating it into the environment. The present invention has been completed as a result of research and development based on these findings.

  1 and 2, the energy recovery method for the high water content biomass 1 of the present invention is that the high water content biomass 1 is placed in an airtight heat insulating container 11 and the biomass 1 is removed from the inside of the container 11 by the steam compressor 12. Moisture is continuously vaporized and sucked, the vaporized moisture is compressed adiabatically by the compressor 12 to increase the temperature of the pressure, and the pressurized water vapor passes through the water vapor condenser 13 that is thermally coupled to the inside of the container 11 to pass inside the container 11 Heat-exchanging with the biomass 1 and evaporating water inside the vessel 11 and condensing the pressurized water vapor to discharge as distilled water 4, thereby separating the high water content biomass 1 into low water content biomass fuel 33 and distilled water 4. Then, the biomass fuel 33 is converted into energy (power) 6 by the power generation device 5, and the distilled water 4 is used as water for the power generation device 5. The adiabatic compression by the compressor 12 may be performed by polytropic compression. Preferably, the water vapor condition at the suction end portion of the water vapor compressor 12 that vaporizes and sucks water from the inside of the container 11 is set to 50 kPa or more in absolute pressure to atmospheric pressure or less, and the water vapor condition on the discharge side of the compressor 12 is atmospheric pressure. That's it.

  1 and 2, the energy recovery device for high water content biomass according to the present invention includes an airtight insulated container 11 having an inlet 19 for high water content biomass 1 and an outlet 20 for biomass fuel 33. A steam compressor 12 having a suction port facing the inside of the container 11 and compressing steam from the suction port, and a discharge port of the compressor 12 and having a heat exchanging part with the inside of the container 11 and from the discharge port A water vapor condenser 13 for condensing the water vapor, and a dehydrator 2 for separating the high water content biomass 1 into a low water content biomass fuel 33 and distilled water 4 after dehydration; and the biomass fuel 33 as energy (power) 6 A power generating device 5 is used which converts the distilled water 4 into water for conversion while converting.

  The method and apparatus for recovering energy of high water content biomass of the present invention comprises dehydrating the water of high water content biomass with a SHPD dryer and separating it into low water content biomass fuel and distilled water, and energy is obtained from the biomass fuel and distilled water. Since it collects, the following remarkable effects are produced.

(B) Compared to the daily or weekly processing time of methane fermentation, the processing time of the SHPD drying device is on the order of time, so the energy recovery processing can be speeded up and cost reduced, and the equipment can be downsized and cost reduced. Is possible.
(B) Since biomass fuel is produced by the SHPD drying device, energy can be recovered from highly hydrous biomass with higher efficiency than methane fermentation.
(C) Since there is no need to separate and remove foreign matters such as paper and plastics mixed in high-moisture biomass, neither drainage (digestion fluid) nor residue (digestion sludge) is generated, so running costs are lower than methane fermentation. Economical.
(D) Therefore, it can be said that it provides a new option for energizing high-moisture biomass that has conventionally been considered to have no means other than methane fermentation.

(E) It is a technology with a low environmental load because it can separate high-moisture biomass into biomass fuel and distilled water, and both can be used effectively for power generation.
(F) Since distilled water can be used for power generation, a self-sufficient energy recovery system for energy and water can be expected from highly hydrous biomass.
(G) By reducing the water content of high water content biomass, it becomes possible to mix and process with low water content biomass such as wood using the same energy recovery system. Economical improvement can be achieved.
(H) Garbage, waste, food industry waste, sewage sludge, waste paper, etc. in urban areas, agricultural waste, aquatic plants, construction waste, etc. in suburbs, forestry waste, livestock waste, etc. in mountainous areas, fishing villages Can contribute to the spread and promotion of energy recovery of various high water content biomass such as fishery waste in the department.

  FIG. 1 shows an outline of a block diagram of the apparatus of the present invention, and FIG. 2 shows a basic structure of a steam heat pump dehydrator (SHPD dryer) 2 used in the present invention. The principle and operation method of the SHPD drying device 2 are described in detail in Patent Document 2 disclosed by the present inventors. The main point in principle is that after the object to be dried is preheated to near 100 ° C, the water vapor generated from the object to be dried is pressurized to increase the saturation temperature and condensed by heat exchange with the object to be dried. It is to heat the dried product.

  The SHPD drying apparatus 2 in the illustrated example includes an airtight insulated container 11 in which an inlet 19 for high water content biomass 1 and an outlet 20 for biomass fuel are bored, a steam compressor 12, a steam condenser 13, and a steam trap 14 And have. The steam compressor 12 has a suction port facing the inside of the container 11, and the discharge port of the compressor 12 is connected to a steam condenser 13 that exchanges heat with the inside of the container 11. When the high water content biomass 1 is put into the hermetic insulation container 11 and preheated to about 95 ° C., for example, the water content of the high water content biomass 1 is reduced to about 84 kPa in the container 11 connected to the suction end portion of the steam compressor 12. Boiling. Since the latent heat of vaporization is lost as it is, the temperature of the biomass 1 rapidly decreases, but by sending the steam discharged from the compressor 12 to the condenser 13 and liquefying it by heat exchange with the biomass 1 at 110 ° C. and 143 kPa, for example, The latent heat of condensation can be reused for heating the high water content biomass 1. However, the pressure on the suction side and the discharge side of the water vapor compressor 12 is not limited to this example, and the water vapor condition on the discharge side (pressure in the container 11) is set to 50 kPa or more in absolute pressure to be equal to or less than atmospheric pressure. The condition (the pressure of the condenser 13) may be set to atmospheric pressure or higher. The pressure in the container 11 is preferably lower than atmospheric pressure from the viewpoint of safety, and the pressure in the condenser 13 is preferably higher than atmospheric pressure for the purpose of omitting the drainage pump and the like.

  In the illustrated SHPD drying device 2, the condensation pressure is higher than the atmospheric pressure, so distilled water (condensed water) 4 spontaneously flows out from the steam trap 14, and noncondensable gas (air etc.) is routed through a pipe that branches from here. Via a discharge valve (not shown) is exhausted spontaneously. That is, the SHPD drying device 2 separates the high water content biomass 1 into the low water content biomass fuel 33 and the distilled water 4 after dehydration. A non-condensable gas can be extracted by an extraction device 15 communicating with the inside of the container 11, and a safety valve for exhausting water vapor to the outside when the internal pressure of the container 11 is abnormal can be provided. In the illustrated example, as an example of the agitation means, the rotating shaft 17 and the agitating blade 18 are rotated by the motor 16 with a reduction gear provided at the top of the hermetic heat insulating container 11, and the biomass 1 in the container 11 is agitated to generate water vapor 23. Promote and move.

  However, the configuration of the SHPD drying device 2 is not limited to the example of FIG. For example, as described in Patent Document 4, the heat transfer area (area for heat exchange with the biomass 1) can be increased by incorporating the water vapor condenser 13 into the stirring blade 18. In order to increase the coefficient of performance COP of the drying apparatus 2, it is important to increase the heat transfer area and reduce the temperature difference (pressure difference) between condensation and boiling. Moreover, although the SHPD drying apparatus 2 of FIG. 2 is a batch (batch) type, if it is the same principle as the above, a continuous type (not shown) may be sufficient. Separation of high water content biomass 1 into low water content biomass fuel 33 and distilled water 4 by dehydration treatment of SHPD dryer 2 greatly expands the range of options for conversion of energy recovered from biomass 1 and power generation methods. The use of various methods over a wide range is possible.

  As shown in FIG. 9, for example, the power generation device 5 generates steam with a biogas fuel-fired boiler 41 using biomass fuel 33 (sawdust 40a and barkyard 40b) as fuel, and the working medium of the steam Thus, the steam turbine 42 and the generator 37 as a prime mover are driven to output electric power 6a (that is, power 6 in FIG. 1). In this case, the distilled water 4 is introduced into the water supply tower 45 as irrigation water in the power generation device 5 and can be effectively used in various fields such as the boiler 41 or the NOx reduction device of the power generation device 5. Moreover, the motive power generator 5 outputs the heat 7 (refer FIG. 1) with the extraction steam from the boiler 41, back pressure steam, and cooling water (not shown). If necessary, a part of the motive power 6 and heat 7 output from the motive power generator 5 is used as predetermined power, preheating, and additional cooking of the steam heat pump dehydrator 2 via the in-house power line 8 and the heat return line 9 (see FIG. 1). Can be used.

  Preferably, the power generation device 5 uses a combination of a pyrolysis gasification / reformation device 30 and an internal combustion engine (heat engine) 53 that are excellent in applicability when converting the fuel 33 to the power 6 (see FIG. 10). ). That is, the biomass fuel 33 is put into the pyrolysis gasification furnace 38 of FIG. 10 and is pyrolyzed and reformed to generate a fuel gas 51. The fuel gas 51 generates an internal combustion engine (heat engine) as a gas-driven prime mover. ) 53, for example, a generator 37 or other power machine is driven via a gas engine, a micro gas turbine or the like to output energy (power) 6. Further, since the condensed water 4 from the SHPD drying device 2 is substantially distilled water, if this is used as makeup water for the waste heat recovery boiler 49 for the gas reforming (water gasification) device 39, the water softening device is consumed. Material (ion exchange resin etc.) can be saved.

The pyrolysis gasification / reformer 30 is a technology for pyrolyzing the biomass fuel 33 in a reducing atmosphere to gasify it. Furthermore, if the generated gas is reformed using high-temperature steam and high-temperature air, a mixed gas containing a large amount of CO (carbon monoxide) and H ₂ (hydrogen) can be obtained. Once the fuel gas 51 is obtained in this way, a power generator (generator 37) using a heat engine 53, which is an internal combustion engine such as a gas engine or a micro gas turbine, or an external combustion engine such as a Stirling engine, as a gas driven prime mover. It is possible to move the fuel cell (not shown) by moving it or obtaining hydrogen by further reforming. In the future, it is also intended to develop technology that increases power generation efficiency to 60-70% by combining SOFC (solid oxide fuel cell) and gas turbine. In addition, fuel such as methanol and dimethyl ether (DME) can be produced from a mixed gas containing a large amount of CO (carbon monoxide) and H ₂ (hydrogen) obtained in the reforming process.

  Various supplementary relationships may be included in the combination of the dehydration process by the SHPD dryer 2 and the power generation process using the pyrolysis gasification / reformer 30. For example, the exhaust heat (heat 7) of the power generation device 5 comprising an internal combustion engine power generation device utilizing pyrolysis gasification is used to preheat and reheat the hermetic insulation container 11 of the SHPD drying device 2 to generate power. The steam compressor 12 and the stirring motor 16 of the SHPD drying device 2 can be driven by the output power (power 6) of the device 5.

  The SHPD drying device 2 and the power generation device 5 in FIG. 1 are not necessarily installed in the same place. Although it is difficult to use the exhaust heat of the power generation device 5 in the SHPD drying device 2 when the distance is long, the biomass fuel 33 and the distilled water 4 of the SHPD drying device 2 are used in the power generation device 5. In addition, it is possible to use the power 6 (electric power) of the power generation device 5 in the SHPD drying device 2. However, it is not always necessary to use it. Even when separated, the biomass fuel 33 by the SHPD drying device 2 is dehydrated and reduced in volume and volume, so that the advantage of the present invention that can greatly improve handling in storage and transportation is recognized. In addition, according to the property and size of biomass, you may add a crushing process and a compaction (compression) process suitably before and after the process of the high water content biomass 1, the SHPD drying apparatus 2, and the power generator 5 of FIG.

[Numerical example of energy balance]
In order to clarify the characteristics of the present invention, if the moisture of the high water content biomass 1 is dehydrated with a small amount of energy consumption by the SHPD drying device 2 as in the present invention, the economic recovery of biomass energy becomes possible, and others The fact that it is difficult to recover economically by using the conventional dehydration method will be described with reference to numerical examples of energy balances shown in FIGS. In FIG. 4, the moisture 31 (= mass of contained water / (mass of biomass dry matter 32 + mass of contained water)) of high moisture content biomass 1 is 80%, that is, the initial moisture mass is four times the amount of dry matter (water content 400). %). Assuming that the high heat value (HHV) of biomass dry matter 32 is 18.8 MJ / kg (4,500 kca1 / kg), 1,000 kg of highly hydrous biomass 1 contains 200 kg of dry matter 32. HHV will be 3,760MJ.

(A) In the case of burning high water content biomass FIG. 4 shows the energy balance when high water content biomass 1 is directly combusted. In the calculation, the high heating value HHV = 3,760 MJ of 200 kg of dry matter in this example exceeds the heat of evaporation of 2,058 MJ of 800 kg of water, and the heating value of 1,702 MJ is subtracted. However, it is difficult to ignite and maintain the combustion of the biomass 1 having the moisture 31 that is four times that of the dry matter 32, and usually requires auxiliary fuel. Even if a combustion furnace such as a fixed bed furnace, a moving bed (stalker) furnace, a fluidized bed furnace, or a rotary kiln is used, this difficulty is difficult to solve. In addition, the combustion temperature does not increase and incomplete combustion is likely to occur, and a large amount of smoke and odor is generated, which is not suitable for practical use.

(B) When a conventional drying apparatus is used FIG. 5 shows a case where biomass fuel 33 is obtained by using conventional drying techniques (hot air drying, conductive drying, vacuum drying, microwave drying, etc.) for dehydration of the high water content biomass 1 Shows the energy balance. For example, 1,000 kg of high water content biomass with an initial moisture of 80% is evaporated and dehydrated to 20% by conventional drying technology. The efficiency of the process of heating from 25 ° C to 100 ° C at 2,743MJ is 80% by the drying steam boiler 34, and the efficiency of the process of drying at 2,058MJ by the conductive dryer 35 is 75% (general value is 50 %), 3,429 MJ is required for drying. On the other hand, 50 kg of moisture remains in the biomass fuel 33 in this state, and 129 MJ is consumed as latent heat of vaporization during the combustion. Therefore, the amount of energy recoverable from the biomass fuel 33 (heat generation amount) is 3,631 MJ. This amount of heat 3,429 MJ required for the drying of the prior art to obtain biomass fuel 33 is slightly less than 3,631 MJ of the calorific value of biomass fuel 33, but in the conduction dryer 35, the agitation power, cooling tower fan and pump power Considering what is needed, it is negative in the end. Therefore, even in this case, economic efficiency is not realized at all.

(C) In the case of methane fermentation FIG. 6 shows the energy balance when energy is recovered from the highly hydrous biomass 1 by methane fermentation. Assuming an average conversion rate from high water content biomass 1 to methane gas is 50%, the energy converted to methane gas is 1,880MJ. Further, assuming that the power generation efficiency of the generator 37 using methane gas is 35%, electric power 658 MJ (183 kWh) and exhaust heat amount 1,222 MJ are obtained. In the methane fermentation apparatus 36, energy is required for pumps and heaters. However, since objective data cannot be obtained, it is not discounted here.

(D) Case of SHPD Drying Device FIG. 7 shows an energy balance when energy is recovered from the high water content biomass 1 using the SHPD drying device 2. When the moisture-containing biomass 1 having a moisture content of 80% is dehydrated to a moisture content of 20% by the SHPD drying device 2, a biomass fuel 33 having a residual moisture content of 50 kg (20% = 50 / (200 + 50)) is obtained. Therefore, when the biomass fuel 33 is burned by the boiler 41, the evaporation latent heat 129MJ with a moisture of 50kg is consumed, so the calorific value is reduced to 3,631MJ. Assuming that the power generation efficiency of the power generator 37 is 35% as in the case of methane fermentation, the power generation amount (electric power) from the biomass fuel 33 is 353 kWh, and the waste heat amount is 2,360 MJ. Next, the electric power and preheating necessary for the operation of the SHPD drying device 2 are subtracted from the obtained energy. As a basis for calculating the amount of electric power required for the operation of the SHPD drying device 2, 10 is used as a COP (coefficient of performance; a value obtained by dividing the amount of latent heat of evaporation of water by the power consumption) from the actual measurement value of the prototype device by the present inventor. Since the amount of latent heat of vaporization at 100 ° C with a water content of 750 kg is 1,692 MJ (469 kWh), the power consumption is 47 kWh divided by the COP value of 10. In addition, about 236MJ is required for preheating 1,000kg of high water content biomass from room temperature 25 ℃ to 100 ℃. When subtracted, the available power is 306 (= 353-47) kWh, the available heat is 2,360 MJ, and a much larger amount of energy can be recovered than 183 kWh in the case of methane fermentation.

(E) When a SHPD drying device and a pyrolysis gasification / reformation device are combined FIG. 8 shows that the power generation device 5 is a pyrolysis gasification / reformation device 30, and the SHPD drying device 2 and pyrolysis gasification / The energy balance from the high water content biomass 1 at the time of combining with the reformer 30 is shown. Even if the cold gas efficiency of the combination of the SHPD dryer 2 and the pyrolysis gasification / reformer 30 is 75% and the power generation efficiency of the combination of the heat engine 53 and the generator 37 is 35%, 183kWh in the case of methane fermentation More energy 227 (= 274-47) kWh can be recovered. Here, the cold gas efficiency is a value obtained by dividing the HHV of the combustible gas contained in the generated gas by the HHV of the raw material used for gasification.

  The following conclusions can be drawn from the numerical examples of each energy balance described above. That is, (A) it is difficult to effectively recover energy without combusting the high water content biomass as it is without any other recovery process (see Fig. 4), and (B) the high water content biomass by the conduction heat transfer type. In the recovery process for dehydration, the difference between the amount of heat (necessary for dehydration) applied to the conduction heat transfer type and the amount of heat that can be recovered is small, and there is a possibility of causing energy loss (see FIG. 5). ) Although the recovery process by methane fermentation can effectively recover energy, it takes more than several days (see FIG. 6). On the other hand, if (D) the recovery process by SHPD drying is performed, energy recovery efficiency is higher than methane fermentation, and distilled water can also be recovered (see FIG. 7). (E) Even when SHPD drying recovery processing and pyrolysis gasification / reforming processing are combined, high-efficiency recovery of energy is possible (see FIG. 8).

  Furthermore, in contrast to methane fermentation, which is a conventional main energy recovery technology for high water content biomass, the dehydration time of the SHPD dryer 2 used in the present invention is several hours to 10 hours and the reaction time is one to two orders of magnitude shorter. The processing time and equipment / equipment costs can be greatly reduced. Moreover, if the biomass fuel 33 after dehydration is subjected to thermochemical conversion by the SHPD drying device 2, most of the energy held by the biomass can be extracted. Furthermore, although not shown in FIG. 6, in the methane fermentation, a treatment for the drainage (digestion fluid) from the fermentation apparatus 36 is required, whereas in the present invention, the drainage treatment is unnecessary, and distilled water 4 is used. Since it is effectively used by the power generation device 5, further improvement in energy recovery efficiency can be expected. In the present invention, for example, ash remains after thermochemical conversion, but the treatment is easy because the amount is small compared to the effluent (digested liquid) and residue (digested sludge) of methane fermentation. Moreover, in the present invention, it is not necessary to strictly separate the components of the high water content biomass 1, and no problem arises even if foreign matter such as plastic is mixed. Therefore, it can be seen that the energy recovery method of the high water content biomass using the SHPD drying device 2 of the present invention can significantly improve the energy recovery efficiency compared to methane fermentation.

  According to the present invention, energy can be quickly and efficiently recovered from the highly hydrous biomass 1 by the SHPD drying device 2. Energy recovery is also possible by methane fermentation, but energy efficiency is lower than that of the SHPD drying device 2, and it takes time. When a dehydration apparatus other than the SHPD drying apparatus 2, that is, combustion, hot air drying, conduction drying, vacuum drying, microwave drying, or the like is used, effective energy recovery from the high water content biomass 1 is difficult. Biomass fuel 33 recovered from the high water content biomass 1 can be converted into power 6 by a power generation device 5 such as a steam generation boiler 41, heat engine 53, heat generating means, pyrolysis gasification / reformer 30, etc. Since the recovered distilled water 4 can be effectively used as the irrigation water of the power generation device 5, the present invention can be expected to realize an energy and water self-sufficient energy recovery system.

  Thus, provision of “a method and an apparatus for recovering energy of high water content biomass having a high processing speed”, which is an object of the present invention, is achieved.

  FIG. 3 shows a biomass fuel 33 which is provided with two input units in the power generation device 5 using the high water content biomass 1 in the embodiment of FIG. 1, and one input unit is the output of the SHPD drying device 2 for the high water content biomass 1. And the example of a structure which connected to the distilled water 4 and connected the other input part to the low hydrous biomass 3 supplied separately is shown. Conventionally, since the energy recovery means from the high water content biomass 1 is substantially limited to methane fermentation, the power generation facility is inevitably made of gas fuel, and the low water content biomass 3 such as wood is connected to the power generation facility. It was difficult. According to the embodiment of FIG. 3, a single power generation device 5 is commonly used for two energy sources that have been conventionally treated separately, namely, a high water content biomass 1 and a low water content biomass 3, and storage facilities and equipment. Can be streamlined.

  According to the present invention, the moisture 31 of the high water content biomass 1 is dehydrated by the SHPD drying device 2 to make the low water content biomass 3 and a new option for energy recovery of the high water content biomass 1 that has been considered to have no option other than methane fermentation. Can be provided. For example, if the high water content biomass 1 is dried to the same water content as the other low water content biomass 3 by the SHPD drying device 2, the low water content biomass 3 and the high water content biomass 1 can be obtained from the system configuration of FIG. Energy can be recovered by a single power generation device 5. This consolidates energy conversion and power generation facilities, and can improve the economics of biomass energy recovery.

It is a block diagram which shows the structure of one Example of this invention. It is explanatory drawing of the water vapor | steam heat pump dehydration apparatus used by this invention. It is a block diagram which shows the structure of the integrated energy collection | recovery apparatus of high water content biomass and low water content biomass. It is a schematic explanatory drawing of the energy balance numerical example in the case of recovering energy by burning high water content biomass. It is an energy balance numerical example in the case of obtaining biomass fuel from high water content biomass using the conventional drying apparatus. It is an energy balance numerical example in the case of recovering energy from a high water content biomass by methane fermentation. It is an energy balance numerical example in the case of recovering energy from high water content biomass using SHPD dryer. It is an energy balance numerical example in the case of recovering energy from highly hydrous biomass using a combination of SHPD dryer and pyrolysis gasification / reformer. It is a schematic block diagram of the energy recovery type | mold power generation device from the conventional low water content biomass. It is a block diagram which shows the structure of the conventional thermal decomposition gasification / reforming apparatus. It is a block diagram of the separate electric power generation and heat utilization apparatus which collect | recovers energy from the conventional low water content biomass and high water content biomass, respectively.

Explanation of symbols

1 ... High water content biomass 2 ... Steam heat pump dehydrator (SHPD dryer)
3 ... Low water content biomass 4 ... Distilled water (condensed water)
5 ... Power generator 6 ... Power (energy)
6a ... Electric power 7 ... Heat 8 ... In-house power line 9 ... Heat return line 11 ... Airtight insulated container
12 ... Steam compressor 13 ... Steam condenser
14… Steam trap 15… Bleeding device
16 ... Motor 17 ... Rotary shaft
18 ... Agitating blade 19 ... Inlet
20… Take-out port 21… Water vapor for preheating and reheating
22 ... Open / close valve 23 ... Water vapor
29… Thermal power generation facilities
30 ... Pyrolysis gasification and reforming equipment
31 ... moisture 32 ... dry matter
33… Biomass fuel 34… Dry steam boiler
35 ... Heat transfer dryer 36 ... Methane fermentation equipment
37 ... Generator 38 ... Pyrolysis gasifier
39 ... reformer 40a ... sawdust
40b… Barkyard (bark)
40c… Waste
41 ... Boiler (combustion) 42 ... Steam turbine
43… Drying equipment in factory 44… Air-cooled condenser
45 ... Water tower 46 ... Water heater
48 ... High-temperature steam / air heater
49 ... Waste heat recovery boiler 50 ... Gas scrubber
51 ... Fuel gas 52 ... Pure water system
53 ... Heat engine (internal combustion engine)
55… Generation and heat utilization of steam turbine drive
56… Biogas-driven power generation and heat utilization

Claims (10)

A high moisture content biomass is put into an airtight insulated container, and the moisture of the biomass is continuously vaporized and sucked from the inside of the container by a steam compressor, the vaporized moisture is adiabatically compressed by the compressor, and the pressure is increased. By passing water vapor through a steam condenser thermally coupled to the inside of the container, heat exchange with the biomass inside the container, evaporating the water inside the container and condensing the pressurized water vapor and discharging it as distilled water, An energy recovery method for high water content biomass in which high water content biomass is separated into low water content biomass fuel and distilled water, the biomass fuel is converted into energy by a power generation device, and the distilled water is used as water for the power generation device. 2. The method of claim 1, wherein the adiabatic compression is polytropic compression. The method of claim 1 or 2, wherein the high water content biomass is any one of the group consisting of undried animal and plant material, food waste, livestock manure, and organic sludge. 4. The method of claim 1, wherein the power generation device converts the distilled water into steam with the biomass fuel as a heat source, and drives a prime mover with the steam. 4. The method according to claim 1, wherein the biomass fuel is converted into a fuel gas by a pyrolysis gas reforming reaction using the distilled water by the power generation device, and a gas-driven prime mover or a fuel cell is converted by the fuel gas. An energy recovery method for high water content biomass that is driven. 6. The energy recovery method for high water content biomass according to any one of claims 1 to 5, wherein the airtight heat insulating container is provided with a stirring means for the high water content biomass. 7. The method according to claim 1, wherein the water vapor condition at the suction end of the water vapor compressor in the container is 50 kPa or more in absolute pressure to atmospheric pressure or less, and the water vapor condition on the discharge side of the water vapor compressor is Energy recovery method for high water content biomass above atmospheric pressure. An airtight insulated container having a high water content biomass inlet and a biomass fuel outlet, a water vapor compressor having a suction port facing the inside of the container and compressing water vapor from the suction port, and a discharge of the compressor A steam condenser that is connected to the outlet and has a heat exchange part with the inside of the container and condenses the water vapor from the discharge port, and converts the high water content biomass into low water content biomass fuel and distilled water after dehydration. A dehydrating device for separation; and an energy recovery device for high water content biomass comprising a power generation device that converts the biomass fuel into energy and uses the distilled water as water for the conversion. 9. The energy recovery apparatus according to claim 8, wherein the power generation apparatus is provided with a biomass fuel-fired boiler and a prime mover using the steam from the boiler as a working medium, and the energy of the highly hydrous biomass in which the distilled water is used as the boiler water. Recovery device. 9. The energy recovery apparatus according to claim 8, wherein the power generator is driven by a pyrolysis gasification / reformation apparatus for converting the biomass fuel into fuel gas by a pyrolysis gas reforming reaction using distilled water, and the fuel gas. A high water content biomass energy recovery device comprising a prime mover or a fuel cell.

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