JP4489536B2 - Carbon dioxide gas application method for greenhouse cultivation - Google Patents

Description

  The present invention relates to a carbon dioxide gas application method for artificially supplying carbon dioxide gas to a greenhouse-grown crop (cultivated plant) to promote growth.

  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, and the carbon dioxide in the greenhouse is adjusted to a high concentration (about 700 to 1500 ppm) exceeding the concentration in the atmosphere, and cultivation is performed. It promotes the photosynthesis of crops to promote growth and enhances quality and yield.

Carbon dioxide gas application to the greenhouse is controlled by diluting the carbon dioxide gas in the gas cylinder containing the liquefied carbon dioxide gas and the carbon dioxide gas in the exhaust gas generated by burning flammable gas and kerosene to an appropriate concentration, Methods and equipment for supplying into a greenhouse are known (for example, see Patent Document 1).
Japanese Patent Laid-Open No. 2001-296641

  When replenishing high purity carbon dioxide gas in the greenhouse, the cost of replenishing carbon dioxide gas is high (about 100 yen / kg), and replenishing the greenhouse throughout the year to expect photosynthesis activation of cultivated crops Is economically difficult. Carbon dioxide gas produced by burning combustible gas and kerosene is cheaper than gas cylinder carbon dioxide gas (about 40 yen / kg), but a large amount of carbon dioxide gas is required when supplied to a large-scale greenhouse throughout the year. Therefore, the share of the running cost of greenhouse cultivation becomes considerably high.

  An object of the present invention is to provide a greenhouse-grown carbon dioxide application method capable of economically advantageous carbon dioxide application even in a large-scale greenhouse.

The present invention extracts the flue gas from the flue of thermal power plants, intended for supplying a processing gas of carbon dioxide-containing material was removed on the failure to crop growth greenhouse grown from the extracted exhaust gas appropriately in the greenhouse Yes, a gas extraction process for extracting exhaust gas from the flue of a thermal power generation facility, a nitrogen oxide removal process for removing nitrogen oxides contained in the exhaust gas extracted in this gas extraction process by a catalytic reduction denitration device, and this nitrogen An ammonia removal process that removes unreacted ammonia contained in the exhaust gas treated in the oxide removal process with an ammonia removal device, and a temperature and humidity suitable for growing greenhouse crops in the dehumidifier after removing the exhaust gas treated in this ammonia removal process. The concentration of carbon dioxide gas by mixing air in the greenhouse into the treated exhaust gas containing carbon dioxide gas treated in the cooling / dehumidifying process. While the concentration of photosynthesis crops promotes, by supplying the process gas in a greenhouse under controlled by the controller so that the speed to accelerate the spray rate to cultivated crops photosynthesis cultivation crops, the It achieves its purpose.

  Here, the flue of the thermal power generation facility is an exhaust duct in a cogeneration system such as a chimney of a thermal power plant or a gas turbine power generation device. From this flue, exhaust gas containing a large amount of carbon dioxide gas is released into the atmosphere throughout the year. By extracting the exhaust gas released into the atmosphere, carbon dioxide gas that promotes photosynthesis of crops grown in greenhouses. By using it effectively, the cost of the carbon dioxide to be consumed becomes substantially zero, and it becomes easy to greatly reduce the running cost even when a large amount of carbon dioxide is used in a large-scale greenhouse. In addition to carbon dioxide, the exhaust gas released into the atmosphere from the flue contains substances that impede the growth of cultivated crops, such as nitrogen oxides. Is supplied to the greenhouse as treated exhaust gas containing carbon dioxide.

  The exhaust gas extraction from the flue here is performed by a gas extraction pipe (extraction duct) with a built-in gas cutoff damper communicated with a part of the flue. A catalytic reduction denitration device, an ammonia removal device, and a dehumidifier are connected in series to this gas extraction pipe, and a suction fan is installed in the middle of the piping that connects the exhaust port of the dehumidifier and the greenhouse. The treated exhaust gas from is sent to the greenhouse. The catalytic reduction denitration device can be applied to existing equipment that removes nitrogen oxides from exhaust gas using ammonia as a reducing agent. This denitration device removes unreacted ammonia remaining in the exhaust gas without being used for exhaust gas reduction treatment. Remove with. The ammonia removal device is, for example, for removing gaseous unreacted ammonia through a water absorption medium. The exhaust gas treated here is a high-temperature, high-humidity carbon dioxide-containing treated exhaust gas, and this treated exhaust gas is dehumidified. It is sent to a vessel, cooled and dehumidified, and the treated exhaust gas containing carbon dioxide at an appropriate temperature and humidity is supplied into the greenhouse, and carbon dioxide is applied to the cultivated crops in the greenhouse.

  In the present invention, depending on the flue gas temperature of the flue of the thermal power generation facility, heating is performed by appropriately heating the flue gas with a heater based on the temperature of the flue gas supplied from the gas extraction step to the nitrogen oxide removal step. Steps can be added. The heat source of the warmer used in this warming process can utilize the exhaust heat of the thermal power generation facility in addition to the commercial power source.

  In the present invention, the treated exhaust gas containing carbon dioxide gas treated in the cooling / dehumidifying process is supplied to the upper space in the greenhouse via the suction fan, the piping, and the air duct, and the treated exhaust gas is supplied from the upper space to the greenhouse. It can be made to spray toward the cultivated crops installed in the lower space of.

  In greenhouse cultivation, it is normal to plant crops by cultivating crops by cultivating crops formed on the floor in the greenhouse, so if carbon dioxide-containing treated exhaust gas is supplied to the upper space in the greenhouse above the cultivation baskets The carbon dioxide gas having a large specific gravity in the processing gas is intensively sprayed toward the crop of the lower cultivation straw. In this way, by concentrating on the cultivated crops and efficiently applying carbon dioxide gas, the photosynthesis of the cultivated crops is effectively promoted, enabling better growth promotion, quality improvement, and yield increase. .

  According to the present invention, exhaust gas that has been released into the atmosphere from the flue of a thermal power generation facility is extracted and effectively used as carbon dioxide that promotes photosynthesis of greenhouse-grown crops. The cost of carbon dioxide to be consumed can be greatly reduced, and it becomes economically easy to replenish carbon dioxide in the greenhouse throughout the year and promote photosynthesis of cultivated crops, especially in large-scale greenhouses. In facilities used in large quantities, the running cost can be significantly reduced. In addition, in order to supply carbon dioxide-containing treated exhaust gas to the greenhouse by removing substances that interfere with the growth of cultivated crops such as nitrogen oxides from the exhaust gas extracted from the flue of the thermal power generation facility, the cultivated crop in the greenhouse It is possible to promote photosynthesis without causing damage, and to improve crop quality and increase yield.

  An embodiment of the present invention will be described with reference to FIG. FIG. 1 shows an outline of a system for processing exhaust gas 3 a discharged from a flue 2 of a thermal power generation facility 1 and supplying it into a greenhouse 4, and a denitration device 40 between the thermal power generation facility 1 and the greenhouse 4. The ammonia removing device 50 and the dehumidifier 60 are arranged in series, and each is connected in series by a damper or a pipe 10 as appropriate.

  In FIG. 1, a gas cutoff damper 20 is installed in the middle of a gas extraction pipe 10a connected to a flue 2 of a thermal power generation facility, and denitration is performed via a heater 30 on the downstream side of the gas extraction pipe 10a. The device 40 is connected. The gas extraction pipe 10 a extracts an appropriate amount of the exhaust gas 3 a from the flue 2 by the opening / closing operation of the gas cutoff damper 20 and feeds it to the heater 30. The warmer 30 is a part that operates when the temperature of the exhaust gas 3a fed from the flue 2 is lower than a specified value and warms it to an appropriate temperature. Depending on the scale, type, etc. of the thermal power generation facility 1 Installed. The denitration device 40 is a catalytic reduction type facility that removes nitrogen oxides NOx from the exhaust gas 3a using ammonia as a reducing agent. There are a plurality of types of existing facilities of different scales, and this existing facility can be applied.

  The denitration device 40 and the ammonia removal device 50 are connected by the pipe 10b, and the exhaust gas from which the nitrogen oxide has been removed by the denitration device 40 is fed to the ammonia removal device 50, and unreacted ammonia in the exhaust gas is the absorption medium. It is absorbed and removed by the fresh water 51. The treated water that has absorbed unreacted ammonia is drained to the waste water treatment unit 52. The outlet of the ammonia removing device 50 and the inlet of the dehumidifier 60 are connected by a pipe 10c, and the treated exhaust gas 3b containing carbon dioxide and treated with the ammonia removing device 50 is sent to the dehumidifier 60, where greenhouse cultivation is performed. Cooled and dehumidified to a temperature and humidity suitable for carbon dioxide application. The cooled and dehumidified treated exhaust gas 3c containing carbon dioxide is sucked by the suction fan 70 and supplied to the upper space Ma in the greenhouse 4 through the pipe 10d.

The greenhouse 4 is, for example, a large-scale greenhouse that grows a large amount of cultivated crops 5 with cultivating rods 6 installed in a large number of rows in the indoor lower space Mb, and an air duct (see FIG. (Not shown) is installed. The treated exhaust gas 3c containing carbon dioxide supplied from the pipe 10d into the greenhouse 4 is blown to the air duct via the control device 80 that automatically controls the concentration of carbon dioxide and the spraying speed to the cultivated crop 5, and the lower part of the air duct is discharged from the air duct. Sprayed toward the cultivated crop 5. The control device 80 mixes the air in the greenhouse with the treated exhaust gas 3b from the pipe 10d so that the carbon dioxide concentration is appropriate for promoting the photosynthesis of the cultivated crop 5, and the spraying speed from the air duct to the cultivated crop 5 Is controlled at a speed suitable for promoting photosynthesis. The control device 80 operates based on various control signals such as a carbon dioxide concentration sensor, a temperature sensor, and a humidity sensor (not shown) provided in the greenhouse.

  Next, the carbon dioxide application operation according to the above-described embodiment will be described.

  When the photosynthesis of the cultivated crop 5 needs to be promoted, the gas cutoff damper 20 is opened, the suction fan 70 is operated, and the carbon dioxide application operation is started. That is, high temperature exhaust gas 3a is extracted from the flue 2 to the gas extraction pipe 10a (gas extraction process), passed through the heater 30 and sent to the catalytic reduction denitration device 40, and the denitration device 40 oxidizes nitrogen in the exhaust gas. Product NOx is removed. This nitrogen oxide is a substance that impedes the growth of the cultivated crop 5 in the greenhouse 4 and is removed by reduction using ammonia (nitrogen oxide removal step). In the removal of nitrogen oxides by ammonia in the denitration device 40, unreacted ammonia remains, and this unreacted ammonia is also a substance that impedes the growth of the cultivated crop 5 in the greenhouse 4, so this is removed from the ammonia removal device. 50 (ammonia removal step).

  The high-temperature exhaust gas 3a from the flue 2 passes through the denitration device 40 and the ammonia removal device 50, so that the treated exhaust gas 3b containing carbon dioxide gas is cooled and dehumidified by the dehumidifier 60 (cooling / dehumidification). Process). The treated exhaust gas 3c dehumidified by the dehumidifier 60 is supplied to the air duct in the upper space Ma in the greenhouse 4 through the control device 80, and blown toward the cultivated crop 5 as carbon dioxide mixed air from the air duct. This air blowing promotes photosynthesis of the cultivated crop 5 and also diffuses carbon dioxide in the cultivated crop 5 so that the carbon dioxide concentration in the lower space Mb in the greenhouse 4 is quickly made uniform. Therefore, even if the floor of the large-scale greenhouse 4 has a large area, there are many cultivated baskets 6 and many cultivated crops 5 are distributed in a plane, the entire cultivated crops 5 are uniformly supplied with carbon dioxide gas. The photosynthesis can be promoted uniformly. In addition, large-scale greenhouse 4 requires a large amount of carbon dioxide, but since these carbon dioxide is obtained from exhaust gas generated in large quantities throughout the year at thermal power generation facility 1, carbon dioxide is supplied at an extremely low cost. As a result, carbon dioxide can be applied throughout the year at an economical advantage with reduced running costs.

  When the gas extraction pipe 10a extending from the flue 2 of the thermal power generation facility 1 to the denitration device 40 is long, or in winter, the temperature of the exhaust gas 3a fed to the denitration device 40 decreases, and gas treatment such as denitration treatment is performed. It can be difficult to do efficiently. Therefore, the temperature of the exhaust gas in the gas extraction pipe 10a is monitored, and when the temperature is lowered to a predetermined low temperature, the warmer 30 is operated to warm up to an appropriate temperature (heating process) and fed to the denitration apparatus 40.

  It should be noted that the present invention is not limited to the above-described embodiment, and it is needless to say that various modifications can be made without departing from the gist of the present invention.

It is a front view which shows the outline | summary of the apparatus which enforces the carbon dioxide gas application method of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Thermal power generation equipment 2 Flue 3a Exhaust gas 3b Treated exhaust gas 4 Greenhouse 5 Cultivation crop 6 Cultivation basket 10 Pipe 10a Gas extraction pipe 20 Gas cutoff damper 30 Heater 40 Contact reduction type denitration apparatus 50 Ammonia removal apparatus 51 Fresh water 52 Waste water treatment part 60 Dehumidifier 70 Suction fan 80 Control device

Claims (3)

Exhaust gas is extracted from the flue of the thermal power generation facility, and treated exhaust gas containing carbon dioxide from which the substances that impede the growth of greenhouse-grown crops are removed from the extracted exhaust gas is appropriately supplied into the greenhouse. In the given method ,
A gas extraction process for extracting exhaust gas from the flue of a thermal power generation facility, a nitrogen oxide removal process for removing nitrogen oxide contained in the exhaust gas extracted in the gas extraction process by a catalytic reduction denitration device, and the nitrogen oxide An ammonia removal step for removing unreacted ammonia contained in the exhaust gas treated in the removal step with an ammonia removal device, and an exhaust gas treated in the ammonia removal step
Including a cooling and dehumidifying process that cools and dehumidifies to a temperature and humidity suitable for greenhouse-grown crop growth in a dehumidifier
Air in the greenhouse is mixed with the treated exhaust gas containing carbon dioxide treated in the cooling and dehumidification process to adjust the carbon dioxide concentration to a concentration that promotes photosynthesis of the cultivated crop, and the spraying speed to the cultivated crop is increased. A carbon dioxide gas application method for greenhouse cultivation, characterized in that the treated exhaust gas is supplied into the greenhouse while being controlled by a control device so as to achieve a speed that promotes . 2. The greenhouse-cultivated carbon dioxide gas application according to claim 1, comprising a heating step of appropriately heating the exhaust gas with a heater based on the temperature of the exhaust gas supplied from the gas extraction step to the nitrogen oxide removal step. Giving method. The treated exhaust gas containing carbon dioxide gas treated in the cooling / dehumidifying step is supplied to the upper space in the greenhouse via a suction fan and a pipe, and the treated exhaust gas is installed in the lower space in the greenhouse from this upper space. The method for applying carbon dioxide gas for greenhouse cultivation according to claim 1 or 2 , wherein the method is sprayed toward a crop.

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