JP2005341953A - Greenhouse cultivation plant residue reuse cogeneration system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cogeneration system so designed that, in a greenhouse plant cultivation, plant residues left after harvesting fruits or the like are utilized as an energy source for a dynamo engine and converted to electric power, waste heat from the dynamo engine is utilized as a heat source necessary for the greenhouse cultivation, and exhaust gas from the engine is utilized for replenishing carbon dioxide into the greenhouse cultivation area. <P>SOLUTION: The greenhouse cultivation plant residue reuse cogeneration system works as follows: Plant residues 3 discharged from a plant cultivation facility 1 into the outside are made into slurry via a hopper 3 for temporarily storing the residues 3 therein and a residue crusher 6. The slurry is delivered via a heater 7 and a hydrothermal gasification reactor 8 to a steam separator 9. The gas extracted from the steam separator 9 is mixed with combustion gas from the outside and fed to a gas engine 13. The exhaust gas from the gas engine 13 is fed via a pressure control means 18 to the plant cultivation facility 1. The waste heat from the gas engine 13 is fed to a radiator 15 in the plant cultivation facility 1. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a technique for reusing plant residues generated in facility cultivation in which plants such as vegetables and fruits are cultivated in an environment partitioned from the external environment.

  JP 2001-292640 A   Tokuhira 11-275965 public information   “Biomass Handbook” issued on September 20, 2002 Editor Japan Energy Association, publisher Ohm Corporation

  The cogeneration system is a power generation system that improves the overall efficiency by generating power with a generator-driven prime mover and collecting exhaust heat generated by driving the prime mover and using it for air conditioning and hot water supply. By the way, in facility cultivation where fruits, vegetables, etc. are cultivated in an environment partitioned from the outside environment such as a greenhouse or a vinyl house, the temperature, lighting, carbon dioxide concentration, etc. in the facility are artificially adjusted, By making it possible to harvest and creating an environment suitable for crops, it increases the value in the market and increases the yield per unit area. In order to make such a cultivation facility environment suitable for plant cultivation, energy is required for heating together with lighting equipment power for facility maintenance and sunshine duration adjustment, so the application of cogeneration system is in facility cultivation The effect of suppressing the increase in energy costs can be expected.

  Furthermore, in the section for facility cultivation, since the circulation with the atmosphere is restricted, the supply from the atmosphere of carbon dioxide gas consumed by the carbon dioxide assimilation of the cultivated plant is restricted, resulting in a shortage of carbon dioxide. A means to replenish carbon dioxide from outside the atmosphere is required. Insufficient carbon dioxide in the facility cultivation section due to the use of carbon dioxide gas (including carbon monoxide gas oxidized by carbon monoxide gas) contained in the exhaust gas of the cogeneration generator drive motor Volume replenishment is possible.

  As a technique for dealing with such a problem, there is a method of purifying carbon dioxide gas in a combustion exhaust gas of a boiler and supplying it to a cultivation facility as disclosed in “Patent Document 1”. Further, in “Patent Document 2”, the biomass material is decomposed and gasified by a biological method, carbon dioxide discharged in the gasification process is supplied to the cultivation facility, and the fuel cell is operated by the generated gas. Techniques have been proposed for using electrical output and heat as required energy for cultivation facilities such as lighting and heating.

  The problem is that the facility cultivation requires means for supplementing the above-mentioned increase in energy costs and the shortage of carbon dioxide gas supply from the atmosphere, but the residue of the cultivated plant (hereinafter referred to as part of the cultivated plant) Of these, processing of parts that are difficult to use in commercial and edible industries, for example, non-standard fruits, leaves, stems, roots, etc., is called a residue. For example, taking tomato cultivation as an example, the weight of available tomato fruit and the weight of the residue are approximately the same. At present, these residues are processed by incineration or plowing into farmland. Not only does this have a negative impact on the environment, but it is necessary to secure the farmland necessary for plowing. There is a contradiction that requires an extra site for residue treatment in the greenhouse cultivation, which aims to increase the yield per unit area. The problem of residue treatment is common to institutional cultivation aimed at fruits such as cucumbers and eggplants other than tomato plants.

Furthermore, with regard to the residue treatment for in-house cultivation, the residue of the main crop in the in-house cultivation contains a large amount of moisture, and the after-harvest residue treatment is carried out in order to carry out the replanting of the next cultivation plant without taking time from the end of the harvest season You must take into account the need to do it in large quantities at once. By the way, the residue of tomato, which is a typical cultivated crop, contains about 40% to 80% moisture.

  The prior art, for example, {Patent Document 1} has answered the problem of supplying carbon dioxide to the cultivation facility using the exhaust gas from the boiler, but requires boiler operation fuel and increases the energy cost required for cultivation. In addition, it cannot cope with the above-described residue treatment.

  The above-mentioned “Patent Document 2” is based on a technique for gasifying a biomass by a biological method, and the reaction is slow. Therefore, a gasification reaction vessel becomes enormous for the treatment of residues generated in large quantities at one time. It may not be suitable for practical use.

  The present invention prevents the adverse effects on the environment when burning and treating the residue generated from the facility cultivation, and the land use efficiency decline when rubbed into the land. An object of the present invention is to solve problems in putting a cogeneration system that reuses plant residues into electrical and thermal energy supply and carbon dioxide replenishment that require residues in greenhouse cultivation.

  The invention described in claim 1 is the above-described problem, in order to decompose and recycle a large amount of plant residue generated in facility cultivation with a high water content in a short time with a small-capacity facility. A hydrothermal gasification process is adopted, and a cogeneration system that drives a gas engine using a combustible gas obtained by decomposing plant residues by the process is configured.

  As described in “Non-patent Document 1”, Part 2, Chapter 7, pages 125 and 126, hydrothermal gasification process is a hydrothermal state (high water temperature, critical temperature, critical pressure) at high temperature and high pressure. It is in a state of water that is indistinguishable between liquid and gas, that is, it is biomass (organic matter derived from animals and plants) in water at a temperature of 647 K or higher and a pressure of 22.1 MPa or higher. In the present invention, it is a process for thermally decomposing the residue of facility cultivation) and generating a combustible gas (referred to as hydrothermal gasification reaction). In the hydrothermal state, water is rich in reactivity, so the reaction is quick, and the moisture contained in the residue also contributes to the reaction.Therefore, the residue drying step as a pretreatment is performed in the treatment of the residue containing a lot of moisture. do not need.

  In the hydrothermal gasification reaction apparatus for performing the hydrothermal gasification reaction, a thin tubular reactor is used, and in order to perform the reaction quickly, the residue as a reactant is broken into pieces and the residue It is necessary to make a slurry mixed with the contained water, and a pulverization slurrying apparatus is installed as a pre-stage facility of the hydrothermal gasification reaction apparatus.

  The product obtained as a mixture of water and combustible gas by the hydrothermal gasification reactor is separated into combustible gas and water by a separation and recovery means, for example, a brackish water separator. The combustible gas is mainly methane, which is used as a fuel for gas engines (including internal combustion engines and gas turbines that use combustible gas as fuel), drives a generator connected to the engine or turbine, and generates electric energy. Converted.

  The combustion exhaust gas of a gas engine passes through a heat exchanger and is cooled by giving thermal energy to a refrigerant (generally cooling water). The exhaust gas after cooling is further discharged into a facility cultivation section through means for removing harmful components such as nitrogen oxides, and supplemented with carbon dioxide gas diluted by carbon dioxide assimilation of plants grown in the facility.

  The heat energy obtained by the cooling refrigerant (generally water) of the cylinder of the gas engine and the heat energy obtained by the refrigerant of the exhaust gas heat exchanger are adjusted for the temperature of the cultivation facility, mainly for heating. Used as

  Since the plant residue generation time is concentrated at the harvest end time of the crop plant, the period during which the residue can be reused is limited. In addition, there are times when the amount of residue generated fluctuates and the required power, heat, etc. cannot be supplied only with the residue. In addition, it is necessary to supply the energy necessary for starting the hydrothermal gasification reactor from the outside. In such a case, there is provided means for taking in fuel gas such as city gas from the outside and supplying it so that the cogeneration system can be operated.

  In the invention according to claim 2, after reducing moisture by pressing the plant residue, the solid content is burned in the boiler, the steam generated by the boiler is used to operate the steam turbine, and the power generation coupled thereto Drive the machine to obtain the necessary power for the cultivation facility, cool the boiler combustion exhaust gas to the waste heat gas heat exchanger, further cool the harmful components such as nitrogen oxides through their removal means, It is invention regarding the cogeneration system comprised so that it may discharge | release in a cultivation facility division.

  The cooling water of the boiler exhaust gas cooling heat exchanger is used as warm water for heating the cultivation facility.

  Applying a hydrothermal gasification process that makes it possible to convert plant residue of a facility-cultivated plant with a high moisture content, which is generated temporarily and in large quantities, into a combustible gas in a short time with a small-capacity facility, The gas produced in step 1 is reused as fuel for a cogeneration system composed of a gas engine. Use the cogeneration system gas engine waste heat and the power generated by the gas engine driven generator as an energy source for maintaining the cultivation facility, and use the gas engine exhaust gas to increase the yield by supplementing carbon dioxide in the cultivation facility. . The invention according to claim 1 configured as described above is suitable for prevention of environmental pollution, reuse of energy, and increase in yield of cultivated plants in a small-scale facility and residue generation situation. This is possible in the form.

  The effect of the invention relating to “Claim 2” is that the plant residue having a high water content is squeezed in the pre-treatment process to reduce the water content and then burned in the boiler, and the turbine generator is driven using the generated steam. Supply the necessary power for cultivation in the facility, supply heat energy to the cultivation facility using the cooling water of the turbine condenser, the boiler exhaust gas cooling heat exchanger cooling water, etc., and from the boiler exhaust gas The extracted carbon dioxide gas is supplied into the facility, and it has the effect of enabling environmental pollution prevention, energy utilization, and increased yield of cultivated plants by reusing plant residues in facility cultivation with a simpler equipment configuration. .

  FIG. 1 shows an embodiment related to “claim 1”. In FIG. 1, a facility cultivation section 1 is partitioned from the outside by walls, roofing materials of glass, vinyl chloride or other suitable materials. Plants are cultivated in the cultivation section 1, and at the end of harvesting, the residues 2 of these plants are carried out from the facility section 1 to the outside. The hopper 3 is a container for temporarily storing the discharge residue.

The residue stored from the bottom of the hopper 3 is cut out and sent to the residue crusher 6 by the cutter feeder 5 that is sent to the next step. The pulverized residue is mixed with moisture contained in the residue to form a slurry, and is sent to the heater 7 which is the next step. After being heated to the required temperature by the heater 7, the hydrothermal gasification reactor 8 is in a water gas mixed state, and the brackish water separator 9 separates gas and water.

The gas separated by the brackish water separator 9 is mixed with gas (for example, liquefied petroleum gas, city gas, etc.) supplied from an external combustible gas supply line 11 in the gas mixer 10 and combusted in the gas engine 13. Supplied as sex gas fuel.
The external flammable gas supply line 11 is replenished when the amount of plant residue is insufficient with respect to the required energy amount of the cultivation facility, and a hydrothermal gasification plant (a process of generating and separating flammable gas from the state of the plant residue (The entire combination of equipment that constitutes the plant is called a hydrothermal gasification plant).

The gas engine is an internal combustion engine 13 using methane gas as fuel. The exhaust gas from the gas engine 13 is guided to the exhaust gas cooling device 14 and cooled to a temperature suitable for injection into the cultivation facility, and at the same time, the cooling water used for gas cooling of the cooling device 14 is supplied to the cultivation facility. It is led to a heat radiator 15 installed inside and used to adjust the temperature in the facility. The exhaust gas that has passed through the exhaust gas cooling device is adjusted to an appropriate pressure by the compression device 16 and temporarily stored in the carbon dioxide gas storage tank 17. The tank 17 is connected with pressure adjusting means 18 and means 19 for releasing carbon dioxide gas into the cultivation facility section. The pressure adjusting means is configured to release the gas stored in the tank 17 to the cultivation facility 1 in accordance with the measured value of the carbon dioxide gas concentration in the cultivation facility 1 by the carbon dioxide gas concentration detection means 19 installed in the cultivation facility. Adjust. When exhaust gas is not supplied to the cultivation facility, the exhaust gas of the gas engine 13 is released directly from the exhaust gas pipe 20 to the atmosphere via the shut-off valve 21.

Cooling water for cooling the cylinder of the gas engine 13 circulates between the cooling water heat exchanger 22 and the engine 13. On the other hand, the coolant that cools the engine coolant in the coolant heat exchanger 22 circulates between the radiator 15 installed in the cultivation facility 1, and the engine 13 obtained from the coolant heat exchanger 22 is discarded. Thermal energy is used to maintain the cultivation facility temperature. Means for adjusting the temperature in the cultivation facility by adjusting the refrigerant flow rate for the cooling water heat exchanger 22 is provided (not particularly shown).

FIG. 2 shows an embodiment corresponding to the invention described in claim 2. In FIG. 2, only the differences from the embodiment corresponding to “Claim 1” shown in FIG. 1 are shown.
The plant residue 2 transported from the cultivation facility 1 of FIG. 1 and put into the hopper 3 is made rich in solid content by removing moisture in the residue 2 by the pressing means 31. The water generated by the pressing process is discarded after being purified by the water treatment means 32.

The residue that is in a solid-rich state by the above process passes through the boiler exhaust gas for burning the residue or a means for drying with the generated steam of the boiler, if necessary, and burns in the boiler 33. The boiler 33 has a burner 34 for fuel gas or liquid fuel supplied from the outside, and the fuel supplied from the external supply gas or liquid fuel supply line 35 can be burned by the burner 34. At the initial start-up of the cogeneration plant according to the present invention, the boiler 33 is started with external fuel, and then plant residue is introduced and the supply of external fuel is adjusted. Even when the amount of plant residue is insufficient, the boiler 33 is operated with external fuel as necessary.

The steam generated by the boiler 33 is supplied to the steam turbine 36 to drive the turbine generator 37 to supply electric energy to the cultivation facility. The cooling water of the condenser 38 of the steam turbine 36 circulates between the condenser cooling water heat exchanger 39 and the heat energy of the condenser cooling water is described in the above item 0024 in the same heat exchanger. Similarly, it is used for temperature adjustment in cultivation facilities.

The combustion exhaust gas generated by the boiler 33 is used for carbon dioxide supply to the cultivation facility and temperature control, as described in the above item 0023.

A diagram showing an embodiment of the invention according to claim 2 is the same as that shown in FIG.

FIG. 1 is a block diagram showing a configuration of the present invention described in “Claim 1”.
FIG. 2 is a block diagram showing the configuration of the present invention described in “Claim 2”, and shows only differences from FIG.

Explanation of symbols

1 --- plant cultivation facility 2 --- plant residue 3 --- hopper 5 --- cutter feeder 6--residue crusher 7--heater 8 --- hydrothermal gasification reactor 9-- -Brackish water separator 10-Gas mixer 11-External combustible gas supply line 13-Gas engine 14-Exhaust gas cooling device 15-Radiator 16-Compression device 17- -Carbon dioxide gas storage tank 18-Pressure adjusting means 19-Carbon dioxide gas concentration detecting means 20-Exhaust gas pipe 21-Closing valve 22-Cooling water heat exchanger 31-Squeezing Means 32 --- Water treatment means 33--Boiler 34 --- Burner 35 --- External fuel supply line 36 --- Steam turbine 37 --- Turbine generator 38 --- Condenser 39 --- Condenser cooling water heat exchange

Claims (2)

A cogeneration system configured as follows.
(1) After pulverizing the facility-cultivated plant residue into a slurry, the combustible gas is generated by the hydrothermal gasification reaction process,
(2) The gas engine power generator is operated using the generated combustible gas as fuel to generate electric power, and (3) the engine waste heat discharged to the gas engine cooling refrigerant is used as the temperature of the cultivation facility. Means used for adjustment, means for cooling and purifying the exhaust gas of the gas engine to replenish carbon dioxide in the cultivation facility, or refrigerant obtained by heat exchange with the exhaust gas of the gas engine is used for the temperature of the cultivation facility Any of the means used for adjustment, or a combination of two or three of the means. A cogeneration system configured as follows.
(1) After making into a residue rich in solid content obtained by squeezing the facility-cultivated plant residue, it burns with a boiler to generate steam,
(2) The steam turbine power generation facility is operated by the generated steam to generate electric power, and
(3) Means for cooling and purifying the combustion exhaust gas of the boiler to replenish carbon dioxide in the cultivation facility, means for utilizing the thermal energy obtained by the steam turbine condenser cooling refrigerant for temperature adjustment of the cultivation facility, or boiler One of the means for using the heat energy obtained by the exhaust gas cooling refrigerant for temperature adjustment of the cultivation facility, or a combination of two or three of the means.

Images