JP5073264B2 - Greenhouse cultivation system - Google Patents

Description

  The present invention relates to a greenhouse cultivation system.

  Greenhouse cultivation (facility cultivation, house cultivation) in which the crops of vegetables and fruits are soil-cultivated and hydroponically cultivated in the greenhouse improves the growth environment (temperature, light, humidity, water, wind, carbon dioxide) of the cultivated crop Because it can be controlled, it is also popular in horticulture. In the case of greenhouse cultivation, during the day, the side windows and skylights of the greenhouse are released and carbon dioxide from the outside air is introduced into the greenhouse to promote photosynthesis of cultivated crops. Carbon dioxide shortage may occur due to lack of ventilation, etc., and good growth of crops may be impaired. In addition, when the greenhouse is closed and the cultivated crop is photosynthesized in winter, the concentration of carbon dioxide in the greenhouse is significantly lower than the concentration in the atmosphere (about 350 ppm), and the growth of the cultivated crop may be suppressed. For this reason, in greenhouse cultivation, carbon dioxide is actively replenished in the greenhouse to adjust the concentration of carbon dioxide in the greenhouse to a concentration suitable for photosynthesis of cultivated crops.

  For this reason, in greenhouse cultivation, electricity, heat, carbon dioxide gas, etc. are supplied to a greenhouse. In general, electricity is supplied by a system power supply (power supplied from a commercial distribution network owned by an electric power company), and heat is supplied by a heavy oil boiler or the like. Carbon dioxide gas is mainly used by diluting exhaust gas with a large amount of air using an LPG or kerosene-fired heater (hot air generator) or the like and supplying it into the greenhouse.

  By the way, in order to effectively use energy, a cogeneration system is used in recent years (Patent Document 1). A cogeneration system is a system that takes out and uses two or more effective energy forms such as heat and electricity from one energy source. That is, the cogeneration system described in Patent Document 1 is a system that can supply power, hot water, and the like simultaneously by combining a gas turbine generator and an exhaust heat recovery heat exchanger.

For this reason, it is conceivable to install gas turbine cogeneration equipment as an energy generation source, supply electricity (electric power) and heat (hot water) to a greenhouse, and use exhaust gas as a carbon dioxide gas source.
JP 2005-69087 A

  However, nitrogen oxides (NOx) are contained in the exhaust gas of the gas turbine. For this reason, the nitrogen oxide concentration is reduced in order to clear the NOx regulation value in the Air Pollution Control Law and related regulations. However, even if the NOx regulation value is cleared, it will hinder the cultivation of crops as it is.

  Regarding the effects of NOx on plants, symptoms such as growth inhibition appear in tomatoes that are often grown in large-scale greenhouses even at low concentrations of about 2-3 ppm. On the other hand, even if the exhaust gas concentration of the gas turbine is low, the exhaust gas contains about 15 ppm of NOx, and the exhaust gas of the gas turbine is not released into the atmosphere but supplied to a closed environment. For this reason, the NOx concentration in the greenhouse may affect plants.

  In particular, as described above, conventional denitration (operation to reduce the concentration of nitrogen oxides) has been developed for the purpose of clearing environmental regulations that are premised on the impact on the human body. There is no cogeneration system with low-concentration denitration technology that is intended to be used.

  In addition, the denitration technology used in other technical fields is mainly an ammonia reduction method using urea water from the viewpoint of ease of handling in an indoor environment. However, a gas temperature of 380 ° C. or higher is required as a reaction temperature at which the reducing medium (urea water) is decomposed into ammonia, and the exhaust gas from the gas turbine equipped with the regenerator is about 260 ° C. It cannot be used as a reducing medium.

  By the way, if exhaust gas from a gas turbine is supplied to a greenhouse, among the effects of nitrogen oxides on plants, there are few signs of harm caused by nitric oxide, and photosynthesis works during contact at 4 and 10 ppm using pinto beans and tomatoes. There is a report that it decreases but recovers as soon as contact is stopped. In general, nitrogen dioxide is said to be five times more toxic than nitric oxide. As for nitrogen dioxide, signs of harm appear in sensitive plants such as pinto beans and tomatoes by contact at 2.5 ppm to 3 pm for 2 hours. As for the symptom, white or yellowish brown irregular shaped spots appear between the veins in the mesophyll and the peripheral part. In addition, typical acute signs of harm as in the case of a high concentration do not appear in a low concentration long-term contact, and at 0.5 ppm or less, the growth of tomatoes and pinto beans is suppressed by continuous contact for 10 to 22 days. However, in rice, the yield may increase even at 55 days of continuous contact at about 0.3 ppm. (Air pollution plant damage photo collection: Japan Public Health Association, Agricultural Pollution Handbook, Jinshokan) However, with the conventional application method (hot air generator using LPgor kerosene), the fuel cost is high and used by photosynthesis The amount of carbon dioxide to be replenished (supplemented to about 350 ppm) and for a short time of application, these NOx concentrations were not a problem, but if carbon dioxide is actively applied to aim for high quality and high yield, NOx, ethylene, carbon monoxide and SOx are considered to be problems.

  In view of the above-described problems, the present invention provides a greenhouse cultivation system that enables effective use of energy and enables high-quality, high-yield cultivation at low cost.

The greenhouse cultivation system of the present invention is a greenhouse cultivation system comprising a gas turbine, a generator using the gas turbine as a power source, and an exhaust heat recovery device for recovering heat from the exhaust gas of the gas turbine , the gas turbine The denitration device that reduces the nitrogen oxide concentration of the exhaust gas from the gas turbine to a value that does not impair the cultivation of greenhouse-grown crops, is disposed between the gas turbine and the exhaust heat recovery device, The denitration apparatus is an ammonia reduction type denitration apparatus that uses ammonia water as a reducing medium. The denitration apparatus uses a reduction catalyst that can be used from a temperature range of 170 ° C., and an exhaust gas temperature of 170 ° C. when it exceeds, and is configured to inject into the exhaust gas in the exhaust nozzle and atomized by the compressed air of ammonia water diluted, concentrated not impair the crop growing The exhaust gas containing nitrogen oxides having a concentration reduced to the above is supplied to the exhaust heat recovery device, and heat and carbon dioxide gas are supplied from the exhaust heat recovery device to the greenhouse for growing the crop, and The power from the generator is supplied to this greenhouse.

  In the greenhouse cultivation system of the present invention, electricity, heat from hot water or steam, and further carbon dioxide gas are supplied to the greenhouse in which crops are grown. In particular, the concentration of nitrogen oxides can be reduced to a value that does not impair crop growth, and the carbon dioxide concentration in the greenhouse can be made suitable for the photosynthesis of cultivated crops.

The denitration apparatus is preferably an ammonia reduction type denitration apparatus using ammonia water as a reducing medium. That is, the exhaust gas (NOx) mixed with ammonia is decomposed into N ₂ and H ₂ O by the reduction catalyst in the denitration apparatus. Further, the denitration apparatus uses a reduction catalyst that can be used from a temperature range of 170 ° C., and when the exhaust gas temperature exceeds 170 ° C., the diluted ammonia water is atomized with compressed air to eject nozzles It is comprised so that it may spray in waste gas from. Thereby, it can spray almost uniformly in a greenhouse.

  According to the greenhouse cultivation system of the present invention, it is possible to control the temperature of the cultivation environment, the CO2 concentration, the amount of sunlight, and the like, and high-quality, high-yield cultivation is possible. In addition, by using the exhaust gas of the gas turbine, it is not necessary to provide a system for removing ethylene harmful to plants, CO that affects workers, etc., and the overall apparatus can be made compact and the cost can be reduced. Is possible.

  Further, if the denitration apparatus is an ammonia reduction type denitration apparatus using ammonia water as a reducing medium, a high denitration rate can be obtained from a low temperature range (for example, 170 ° C.) to a high temperature range (for example, 500 ° C.). A high denitration rate can be exhibited with respect to the exhaust gas of a gas turbine at about ° C. Moreover, it is advantageous in terms of equipment costs and running costs.

  Embodiment of the greenhouse cultivation system which concerns on this invention is described based on FIGS.

  The whole block diagram of the greenhouse cultivation system which concerns on FIG. 1 at this invention is shown. This greenhouse cultivation system is a trigeneration system that uses carbon dioxide (carbon dioxide) contained in the exhaust gas of a cogeneration system.

  The greenhouse cultivation system includes a gas turbine 1, a generator 2 that uses the gas turbine 1 as a power source, and an exhaust heat recovery device 3 that recovers heat from the exhaust gas from the gas turbine 1. Hot water) and carbon dioxide (carbon dioxide). In this case, the denitration device 5 is disposed between the gas turbine 1 and the exhaust heat recovery device 3.

  The gas turbine 1 includes a compressor 6 that compresses combustion air, a combustor 7 that combusts combustion air and fuel pressurized by the compressor 6, and a fuel gas discharged from the combustor 7. Is converted to rotational energy, and the generator 2 is driven, and electric power is obtained by driving the generator 2. Further, the exhaust gas of the gas turbine 1 is supplied to the exhaust heat recovery device 3 through the denitration device 5. The exhaust heat recovery device 3 recovers the heat of the exhaust gas that has passed through the denitration device 5 to generate hot water.

  The denitration device 5 is an ammonia reduction type denitration device, and is disposed at the inlet of the denitration device of the tank 10 storing ammonia water, the denitration reaction tower 11 and the exhaust gas duct 12 of the gas turbine 1 as shown in FIG. A jet nozzle 13, a compressor 14 that supplies compressed air, a pump (pulse pump) 15 that sends ammonia water in the tank 10 to the jet nozzle 13, and the like.

  As the ammonia water, one diluted to 10% with purified water is used, and as the ejection nozzle 13, the diameter (diameter) of the ejection hole is set to about 1.0 mm, for example. At this time, the ejection from the ejection holes of the ejection nozzle 13 is controlled by the control means 9. That is, when the exhaust gas temperature exceeds a predetermined set value (for example, 170 ° C.), ammonia water (compressor) is supplied to the exhaust gas (exhaust gas supplied from the gas turbine 1 through the exhaust gas duct 12 to the denitration reactor 11). 14 (ammonia water, which is a reducing medium atomized by compressed air supplied from 14) is sprayed (sprayed) from the ejection nozzle 13. Here, purified water is water that complies with the water quality standards set by the Japanese Pharmacopoeia, and is either normal distillation (tap water), distillation, ion exchange, or ultrafiltration (reverse osmosis method / ultrafiltration). Or water treated by a combination of these methods.

  That is, the control means 9 supplies the compressed air from the compressor 14 when the temperature detected by the temperature detector 16 (such as a thermistor) and the temperature detected by the temperature detector 16 exceeds a set value (170 ° C. in this case). A signal generator 17 or the like for transmitting an operation signal is provided.

  Further, as shown in FIG. 3, the lid member 20 of the tank 10 has a pair of through holes 18, 18, and a vent pipe (vent pipe) 19. The vent pipe 19 includes an inverted J-shaped pipe main body 19a that rises from the lid member 20, and a flange portion 19b that is provided in an opening opened below the pipe main body 19a. A feeder is arranged. Note that mounting holes 40 are provided on the outer peripheral side of the lid member 20 at a predetermined pitch along the circumferential direction. For this reason, the bolt member is screwed to the tank body via the mounting hole 40 in a state where the upper opening of the tank body (bottomed cylindrical body) (not shown) in which ammonia water is accommodated is closed with the lid member 20. By doing so, the lid member 20 can be attached to the tank body.

  Ammonia water is supplied to the tank 10 from a replenishment tank 21 as shown in FIG. That is, the replenishment tank 21 is provided with a pair of cocks 22a and 22b, one (lower side) cock 22a is connected to an ammonia water supply hose 23, and the other (upper side) cock 22b is connected to the other cock 22b. The hose 24 for air is connected. In addition, as this replenishment tank 21, a commercially available poly tank (polyethylene tank) can be used.

  By opening both the cocks 22 a and 22 b, the ammonia water in the replenishment tank 21 in the replenishment tank 21 is supplied to the tank 10 via the ammonia water supply hose 23. At this time, an amount (amount) of air corresponding to the supplied ammonia water enters the replenishment tank 21 via the air hose 24. In addition, couplers (conduit connections) 25 and 25 are interposed in the ammonia water supply hose 23 and the air hose 24, respectively, to prevent the suspension from entering when the ammonia water is replenished. In addition, an ammonia water supply hose 23 is connected to one through hole 18a of the lid member 20 of the tank 10 via a joint (bamboo joint) 29, and a joint (bamboo joint) is connected to one through hole 18b. An air hose 24 is connected through 29.

  Moreover, since the jet nozzle 13 has a small hole diameter, the jet nozzle 13 may be blocked. For this reason, as shown in FIG. 5, a purge air supply path 27 is connected to the ammonia water supply path 26 to enable air purge. That is, the purge air supply path 27 is branched from the air supply path 28, and the purge air supply path 27 is connected to the ammonia water supply path 26. In this case, an opening / closing valve 30 is interposed in the ammonia water supply path 26, an opening / closing valve 31 and a check valve 32 are interposed in the purge air supply path 27, and a check valve 33 is interposed in the air supply path 28. Is done.

  The supply of purge air from the purge air supply path 27 to the ejection nozzle 13 is performed, for example, once every predetermined time (1 hour) for about 10 seconds. That is, when supplying ammonia water to the nozzle 13, the on-off valve 31 is closed and the on-off valve 30 is opened. Thus, purge air is not supplied from the purge air supply path 27 to the injection nozzle 13, and ammonia water is supplied from the ammonia water supply path 26 and air is supplied from the air supply path 28 to the injection nozzle 13. At the time of air purge supply, the on-off valve 30 is closed and the on-off valve 31 is opened. Thereby, the supply of the ammonia water from the ammonia water supply path 26 to the injection nozzle 13 is stopped, and the air from the purge air supply path 27 is supplied to the injection nozzle 13. When the driving of the turbine 1 is stopped, the purge air is continuously supplied until the temperature of the exhaust gas in the exhaust gas duct 12 (the temperature detected by the temperature sensor 16) becomes, for example, 100 ° C. or less. It is preferred to do so.

  As shown in FIGS. 1 and 2, the denitration reaction tower 11 and the exhaust heat recovery device 3 are connected via a gas pipe 35, and the exhaust heat recovery device 3 and the greenhouse 4 are connected via a carbon dioxide supply pipe 36. Yes. Further, the exhaust heat recovery device 3 and the greenhouse 4 are connected by a hot water going-out pipe 37 and a hot water return pipe 38. The electric power generated by the generator 2 is supplied to the greenhouse 4 via the cable 34.

  The exhaust heat recovery device 3 includes a heat exchanger, and heat exchange is performed between the heat of the exhaust gas and the water of the exhaust heat recovery device 3 in this heat exchanger to generate hot water. Then, the generated warm water is supplied to the greenhouse 4 via the warm water outlet pipe 37. In addition, the hot water (low temperature water) used for heat supply in the greenhouse 4 and having a low temperature returns to the exhaust heat recovery device 3 through the warm water return pipe 38 and is warmed again by the exhaust gas.

  Next, the process of supplying electricity, heat and carbon dioxide gas to the greenhouse 4 in this greenhouse cultivation system will be described. By driving the gas turbine 1, the generator 2 is driven to obtain electric power, and this electric power is supplied to the greenhouse. The exhaust gas from the gas turbine 1 is supplied to the denitration reaction tower 11. In the denitration reaction tower 11, denitration is performed by a selective reduction catalyst method (SCR) using ammonia as a reducing agent. As the denitration catalyst, a catalyst containing titanium oxide containing vanadium or tungsten alone, or a catalyst containing both of them is used.

  In this case, the ammonia water in the tank 10 (10% purified water dilution) is sent to the nozzle 13 by the pump 15 when the exhaust gas temperature reaches a certain temperature (for example, 170 ° C.), and the compressor 14 Compressed air is sent out to the nozzle 13 side, and exhaust gas atomized by compressed air is injected from the nozzle 13 to the denitration reaction tower 11.

The exhaust gas (NOx) mixed with ammonia is decomposed into N ₂ and H ₂ O by the reduction catalyst in the denitration reaction tower 11 as can be seen from the following reaction formula 1. At this time, the ratio of ammonia to exhaust gas (NOx) is 1: 1.

  Thereby, the carbon dioxide of the exhaust gas containing nitrogen oxides having a concentration that does not impair crop growth is supplied from the exhaust heat recovery device 3 to the greenhouse 4 through the carbon dioxide supply pipe 36. Further, the hot water generated by the exhaust heat recovery device 3 is supplied to the greenhouse 4 via the hot water going-out pipe 37, and the hot water (low temperature water) that has been used to supply heat in the greenhouse 4 and becomes a low temperature is supplied to the hot water return pipe 38. Is returned to the exhaust heat recovery device 3 and again warmed with exhaust gas. That is, a hot water circulation path is formed between the exhaust heat recovery device 3 and the denitration device 5, the warm water warmed by the exhaust heat recovery device 3 is supplied to the greenhouse 4, and the warm water having a low temperature in the greenhouse 4 is Returning to the exhaust heat recovery device 3.

  In the present invention, electricity, heat from hot water or steam, and carbon dioxide are supplied to a greenhouse for growing crops. For this reason, it is possible to control the temperature of the cultivation environment, the CO2 concentration, the amount of sunlight, etc., and high quality, high yield cultivation is possible. In particular, the carbon dioxide gas concentration in the greenhouse can be adjusted to a concentration suitable for the photosynthesis of the cultivated crop, and stable cultivation of the crop in the greenhouse is possible.

Further, since the denitration apparatus is an ammonia reduction type denitration apparatus using ammonia water as a reducing medium, a high denitration rate can be obtained from a low temperature range (for example, 170 ° C.) to a high temperature range (for example, 500 ° C.). For this reason, a high denitration rate can be exhibited with respect to the exhaust gas of the gas turbine 1 at about 260 ° C. Moreover, it is advantageous in terms of equipment costs and running costs.

  Further, the ammonia water can be supplied to the tank 13 easily from a commercially available poly tank (polyethylene tank) (replenishment tank), and the ammonia water can be stably supplied to the tank 13. Moreover, a filter is disposed on the vent pipe 19 of the lid member 20 of the tank 13 and the suspension of the aqueous ammonia can be effectively prevented. Ammonia water can be stably injected into the exhaust gas.

  By the way, in such a greenhouse cultivation system, a generator is driven by a gas engine to generate electric power and supply electric power. At the same time, exhaust heat of exhaust gas is recovered in the form of steam, hot water, etc., and used for air conditioning, hot water supply, etc. A gas engine system can be used. However, in the supply of carbon dioxide gas by a gas engine, exhaust gas contains ethylene harmful to plants in addition to NOx, and high-concentration CO that is thought to affect workers, and supplies it to a closed greenhouse. In some cases, plants and workers may be affected. In order to remove the NOx removal system, a system for removing ethylene and CO is required, and the apparatus becomes complicated and expensive.

On the other hand, in the present invention, by using the exhaust gas of the gas turbine 1, it is not necessary to provide a system for removing ethylene harmful to plants, CO that affects workers, and the like, and the entire apparatus can be made compact. In addition, the cost can be reduced.

  When using a micro gas turbine (a small gas turbine of about 500 kW), in order to set the CO2 concentration in the greenhouse to the optimum concentration (1000 ppm to 1500 ppm), it is 50 kW in a 1 ha scale greenhouse. About one class-class micro gas turbine is required.

  The following table 1 shows the CO2 concentration when exhaust gas of one MGT (micro gas turbine) 50 kW is applied to a greenhouse with a floor area of 1 ha and an eave height of 5 m. If this exhaust gas is applied to a greenhouse without denitration, the concentration of NOx is as shown in Table 2 below.

  When applied for 5 to 6 hours, it becomes 2 ppm or more, and there is a possibility that signs of harm appear, and it is difficult to apply carbon dioxide for a long time. Even if the concentration is 0.5 ppm, it is conceivable that the growth is suppressed by long-term contact. Therefore, if it is applied for about 1 hour, it exceeds 0.5 ppm.

  For this reason, when using the carbon dioxide gas of exhaust gas, it is necessary to apply a low concentration denitration technique. However, in a gas turbine equipped with a regenerator, the exhaust gas temperature is relatively low and the NOx concentration is relatively low, so there are the following problems in applying the conventional technology.

  As shown in Table 3 below, there are combustion improvement, dry denitration method, and wet denitration method as NOx reduction techniques for fixed sources. As for combustion improvement, it is used when the NOx reduction rate is a relatively low demand (to the extent that the environmental regulation value is cleared), and it is difficult to reduce the concentration to a level that does not hinder greenhouse crops. Further, since it is considered that the cost of remodeling and development costs of the gas turbine is increased, this method cannot be selected. In Table 3, ◎ indicates excellent, ◯ indicates good, Δ indicates slightly inferior, and × indicates inferior.

  In addition, the wet denitration method requires an expensive oxidizing agent, and a large amount of nitrogen oxide is contained in the waste liquid, which makes the treatment complicated, so that it is difficult to select this method. Dry denitration methods include ammonia catalytic reduction, non-catalytic ammonia reduction, electron beam irradiation, and activated carbon adsorption.

  The non-catalytic ammonia reduction method has a low denitration rate and a large amount of leaked ammonia, and the electron beam irradiation method and the activated carbon adsorption method have a high running cost and equipment cost, and are difficult to select in consideration of versatility. In the ammonia catalytic reduction method, a high denitration rate can be easily obtained using a catalyst and ammonia, and the conditions suitable for the economy are met, but there is no example in terms of denitration of this low concentration NOx, which will be described later. As shown above, there was a problem with applicability and verification was necessary. There are other denitration methods using unburned HC in exhaust gas and denitration methods using CO. However, since the combustion temperature is high in a gas turbine, unburned HC is not generated and cannot be used. As for the denitration method, the gas turbine cannot be applied because the O2 concentration in the exhaust gas is too high (16% with respect to the theoretical air combustion) and the amount of generated CO is small.

  In addition, the ammonia reduction method using NH3 has been conventionally adopted for fixed sources, and NH3-SCR (selective reduction catalyst: titanium oxide containing vanadium or tungsten alone or those containing both) is used. Further, there is a catalyst that can be used in a temperature range of 170 ° C. to 350 ° C., and the reaction temperature can be applied to a turbine exhaust gas of about 280 ° C. (There are also types of catalysts corresponding to about 280 ° C to 420 ° C and 380 ° C to 500 ° C)

  On the other hand, in the present invention, natural gas with no sulfur content is assumed in the present invention, and the sulfur content (S content) which is a poisoning substance of the catalyst is not generated. Denitration is possible. (For C heavy oil, etc., the denitration temperature is usually 320 ° C or higher)

  Conventionally, urea water is generally used as a reducing medium because it is easy to handle and low in running cost. However, in order to maintain the desired denitration performance, the exhaust gas temperature is raised to 380 ° C. (urea lower limit temperature). It is necessary to control within the use range of ~ 420 ° C (catalyst upper limit, applicable to temperatures higher than this, and denitration efficiency is inferior), and output change and seasonal change of intake air temperature within this use range (40 ° C) It was difficult to control the minute (about 70 ° C.). In addition, when the temperature falls below 380 ° C. in operation, urea does not decompose into ammonia and carbon dioxide and does not function as a reducing agent, but also becomes a by-product such as cyanuric acid and burette and adheres to the catalyst surface as white crystals. There is a possibility that troubles such as corrosion of the exhaust heat utilization equipment (exhaust heat recovery type chiller / heater, exhaust heat boiler, etc.) and casing after blocking will occur. Also, when used at a high temperature before the regenerator, the gas turbine needs to be significantly modified, and the catalyst deteriorates quickly at temperatures higher than 500 ° C. Decreases. On the other hand, ammonia as a reducing medium is effective in the temperature range (170 ° C. to 300 ° C.). However, an administrator who has qualifications for handling ammonia gas and high-concentration aqueous ammonia is required. In the case of ammonia gas, it is also necessary to send it to the fire department.

  Moreover, since the NOx concentration of the gas turbine exhaust gas is low, the injection amount of NH3 water as a reducing medium (25% ammonia water, 0.03 liter / h) is very small, and the pump can be controlled during delivery. Have difficulty. Further, when the blowout is not uniform, the denitration efficiency may be lowered.

  In addition, NH3-SCR (selective reduction catalyst: titanium oxide containing vanadium or tungsten alone or containing both) can be used from a temperature range of 170 ° C. and about 280 ° C. Since it is applicable to the exhaust gas of a turbine, it was applied to the present invention.

  Further, in the reducing medium in question, the use area of urea is 380 ° C. or higher and cannot be used at the gas turbine exhaust gas temperature after the reheater. Therefore, in the present invention, the gas turbine exhaust gas temperature ( Even at about 280 ° C., ammonia that functions as a reducing medium was used. At that time, when ammonia gas is used, since it becomes a high-pressure gas, the pressure is high and the pressure is reduced, so that it is difficult to handle compared to ammonia water. In addition, the amount of the liquefied ammonia cylinder that is naturally vaporized varies depending on the amount of the remaining liquid in the cylinder, so that there is a problem in controllability. Furthermore, confirmation of the remaining amount can only catch changes in pressure.

  For this reason, in the present invention, the ammonia water concentration is set to 10% for easy handling, and the pumping amount is increased. Specifically, a small amount of ammonia water is sent out by a pulse pump 15 and is atomized by compressed air sent from a compressor 14 from a nozzle 13 (ejection hole 1.0 mmΦ) installed in the exhaust gas pipe so as to be ejected into the exhaust gas. I made it. This eliminates the need for delivery to a fire department or the like, and enables control of the pump when sending ammonia water, thereby improving the denitration efficiency.

  Further, since the nozzle tip and the nozzle tip are exposed to a high temperature environment, the nozzle may be clogged with a slight suspension, calcium in ammonia water, or the like. For this reason, in the present invention, the purge air is supplied from the purge air supply path 27 to the ejection nozzle 13 to prevent the nozzle from being blocked. As a result, the ammonia water can be stably supplied, and denitration can be performed efficiently.

  In addition, for the purpose of a solution to agriculture, it is desirable that it is easy and safe to handle and does not require qualifications such as deleterious substances and poisonous substances. In the case of ammonia gas and high-concentration ammonia water by the above denitration method, qualification is necessary for handling, and there is a problem in the system if specifications in the greenhouse or the like are taken into consideration. Further, urea water that does not require qualification is not sufficiently reacted at about 270 ° C. of the MGT exhaust gas, and if the denitration is used at a high temperature before the reheater, a significant modification of the MGT (micro gas turbine) package is required.

  Ammonia can also have an adverse effect in the plant cultivation environment. Ammonia is about several ppm, and it enters the body from the pores of the crop and deprives the cells of oxygen, so the damage is sudden and the damaged leaves are darkened and wilted. Therefore, it is necessary to reduce the residual ammonia concentration and NOx at the denitration outlet to zero at the same time.

  Therefore, in the present invention, the energy source and carbon dioxide generation source in the trigeneration system are gas turbines, and the fuel used is natural gas. This prevents the generation of SOx, prevents the generation of ethylene and carbon monoxide, which are problematic when carbon dioxide is applied by a gas engine as described above, and eliminates the need for installing a removal device for the toxic substance. The increase in size was prevented.

  As described above, the embodiment of the present invention has been described. However, the present invention is not limited to the above-described embodiment, and various modifications are possible. For example, the concentration of ammonia water in the denitration apparatus 5, the delivery amount, etc. The concentration can be arbitrarily changed within a range in which the concentration of nitrogen oxides can be reduced to a concentration that does not impair crop growth.

Next, the Example about the effect of a denitration apparatus is shown. Table 4 shows the results of the assumption of the NOx concentration at the inlet of the denitration device and the greenhouse NOx concentration according to the amount of exhaust gas. In this case, the gas amount at the inlet of the denitration apparatus is 1400 m ³ / h, and the NOx concentration (converted to 16%) is 17 ppm.

Table 5 shows the assumed results of NOx concentration after denitration and greenhouse NOx concentration based on the amount of exhaust gas. In this case, the amount of gas at the outlet of the denitration apparatus is 1400 m ³ / h, and the NOx concentration (act) is 0.2 ppm.

  The greenhouse concentration is almost 0 ppm, and it is considered that there is no inferiority compared with the concentration in the atmosphere. Moreover, it is less than the environmental regulation value of NOx 0.04-0.06 ppm.

The concentration of carbon monoxide and the CO concentration in the greenhouse are shown in Table 6 below. In this case, the gas amount at the outlet of the denitration apparatus is 1360 m ³ / h, and the CO concentration is 13 ppm. Since the concentration of carbon monoxide is significantly lower than the environmental regulation value of 10 ppm, it can be determined that the work environment is not affected.

1 is a simplified overall view of a greenhouse cultivation system showing an embodiment of the present invention. It is a simplified block diagram of the denitration apparatus of the greenhouse cultivation system. The tank of the denitration apparatus of the said greenhouse cultivation system is shown, (a) is a top view of a cover member, (b) is a side view of a cover member. It is a simple perspective view of the replenishment tank of the denitration apparatus of the said greenhouse cultivation system. It is a simplified diagram showing an ammonia water supply circuit of a denitration apparatus of a greenhouse cultivation system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Gas turbine 2 Generator 3 Waste heat recovery apparatus 4 Greenhouse 5 Denitration apparatus 13 Injection nozzle 38 Piping

Claims (2)

A greenhouse cultivation system comprising a gas turbine, a generator using the gas turbine as a power source, and an exhaust heat recovery device for recovering heat from the exhaust gas of the gas turbine,
The fuel used in the gas turbine is natural gas,
A denitration device that reduces the nitrogen oxide concentration of the exhaust gas of the gas turbine to a value that does not impair the cultivation of greenhouse-grown crops is disposed between the gas turbine and the exhaust heat recovery device,
The denitration apparatus is an ammonia reduction type denitration apparatus that uses ammonia water as a reducing medium,
In the denitration apparatus, a reduction catalyst that can be used from a temperature range of 170 ° C. is used, and when the exhaust gas temperature exceeds 170 ° C., the diluted ammonia water is atomized by compressed air and discharged from an ejection nozzle. It is configured to inject into exhaust gas,
An exhaust gas containing nitrogen oxides at a concentration that does not impair crop growth is supplied to an exhaust heat recovery device, and heat and carbon dioxide gas are supplied from the exhaust heat recovery device to the greenhouse for growing the crop. A greenhouse cultivation system characterized by supplying power from the generator to the greenhouse. Greenhouse system according to claim 1, wherein the supply of the purge air for preventing clogging to jet nozzles, and carrying out at the time of driving of the gas turbine.

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