JPH03236724A - Greenhouse cultivation of plant and system therefor - Google Patents

Abstract

PURPOSE:To provide the title system intended to utilize the gas generated from methane fermentation facilities for heat source and the photosynthesis promotion for plants, so designed that carbon dioxide stored by separating methane from gas generated from methane fermentation facilities is fed for the photosynthesis promotion for plants. CONSTITUTION:The methane fermentation gas generated from a methane fermentation facility 1 is raised in pressure to a specified level using a booster 2 and cooled by a cooler 3 to reduce its moisture content. The resulting gas is introduced into adsorption columns 4 each packed with an adsorbent, where adsorption of carbon dioxide in the fermentation gas is alternately performed by alternately changing the pressure in the respective columns. The resulting methane freed from carbon dioxide through its adsorption and separation is passed through the columns and introduced into a tank 7 where it is stored. The carbon dioxide adsorbed above is desorbed by a vacuum pump 6 and introduced into a tank 7 where it is stored. This carbon dioxide, according to the carbon dioxide concentration in a greenhouse 8, is fed, via a feeding means 9, into the greenhouse 8. The methane stored in the tank 5 is consumed as a fuel into an energy source for the space heating and cooling of the greenhouse 8 and the methane fermentation facility 1, etc. Feed of carbon dioxide or methane is controlled by a controlling means 11 according to the conditions desired.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for cultivating plants in a greenhouse and a system used therefor, and more particularly, to an improvement in greenhouse cultivation of plants by applying so-called carbon dioxide gas.

(Conventional technology and issues to be solved) In recent years, in greenhouse cultivation of plants, in order to prevent the carbon dioxide concentration in the greenhouse from decreasing during sunlight, which inhibits photosynthesis and reduces quality and yield, So-called carbon dioxide application, which directly supplies carbon dioxide into the greenhouse, is being carried out.

In general, such carbon dioxide application methods include an oil combustion method in which petroleum is burned to generate carbon dioxide gas, a cylinder method in which carbon dioxide gas is generated from an industrial liquefied carbon dioxide gas cylinder, and an L
A gas combustion method is used in which gas such as PG is burned to generate carbon dioxide gas.

However, in these days when global warming due to carbon dioxide gas is a problem, even if the quality and yield can be improved by applying carbon dioxide gas, it is necessary to use far more carbon dioxide gas than is actually necessary for the application of kerosene. The generation of carbon dioxide by burning fossil fuels such as carbon dioxide and LPG, and the diversion of industrial carbon dioxide gas made from fossil fuels are also problems in related fields.

Furthermore, there is an urgent need to take measures to deal with methane, which, along with carbon dioxide gas, is an organic substance that causes global warming.

In view of these circumstances, the present inventors have conducted extensive studies to solve these problems in carbon dioxide application. As a result, carbon dioxide gas, which is highly concentrated in methane fermentation gas generated by methane fermentation of biomass such as sewage treatment sludge, can be used cheaply and efficiently, and its global warming effect is 20 to 40 times that of carbon dioxide gas. They discovered that these problems could be solved by burning methane, which is said to be a strong carbon dioxide gas, and converting it into carbon dioxide, while at the same time recovering and effectively using the heat.

In other words, large amounts of carbon dioxide gas are released along with methane gas from such biomass, and conventionally, these gases were released into the atmosphere as they are, but the present inventors first developed a pressure swing method to extract these gases. After learning that carbon dioxide gas can be efficiently recovered and highly purified methane can be obtained, a patent application was filed (Japanese Unexamined Patent Publication No. 122018/1983). After further investigation, it was discovered that this technology could be applied to improve carbon dioxide application.

(Means to Solve the Problems) As one aspect of the present invention, when plants are cultivated in a greenhouse, gas generated from a methane fermentation facility is separated and accumulated into carbon dioxide gas and methane by a pressure swing method, and the This invention provides a method for cultivating plants in a greenhouse, characterized by supplying carbon dioxide gas to promote photosynthesis of plants, burning methane to use it as a heat source, and recovering and effectively utilizing waste heat. .

According to the present invention, the carbon dioxide gas contained in methane fermentation gas, which has conventionally been released into the atmosphere, can be used inexpensively and effectively, so that the above-mentioned problems with conventional carbon dioxide application can be solved. Not only that, the separated methane also has the advantage of being reusable, for example, as a heat source for greenhouse heating or as a fuel for various heat engines.

Thus, the method of the present invention is not particularly limited to target plants, and can be applied to fruit trees, vegetables, etc. that are usually grown in greenhouses.
Can be applied to any flower, such as melons, tomatoes, cucumbers, peppers, green peppers, strawberries, eggplants, etc.
It can be suitable for cultivating lettuce, chrysanthemums, carnations, persimmons, grapes, etc.

Further, the methane fermentation facility is not particularly limited as long as it is an anaerobic fermentation facility that generates methane fermentation gas containing carbon dioxide gas. Examples include anaerobic fermentation equipment that processes sewage treatment sludge, human waste, etc., and anaerobic fermentation equipment that processes a wide range of biomass such as livestock manure, corn, sugar cane, vegetables, and fruit scraps. For example, methane fermentation gas from digestion of sewage treatment sludge usually contains 35 to 40% by volume of carbon dioxide gas, and is suitably used in the method of the present invention.

Furthermore, the pressure swing method itself is a known method, for example, the above-mentioned Japanese Patent Application Laid-Open No. 58-12
The method of No. 2018 can be adopted.

That is, a pressure swing device equipped with one or more gas adsorption towers is used, and preferably 10 kg 7 cm"G
Hereinafter, the apparatus is more preferably operated according to a conventional method at a pressure of about 2 to 5 kg/cm'G. If the pressure is too high, equipment costs will be high, and energy costs will also be high. Also, if the pressure is too low, the device will become too large, which is not a good idea. As the adsorbent, known ones such as carbon molecular sieve, zeolite molecular sieve, silica gel, alumina gel, etc. can be used alone or in combination, and carbon molecular sieve is particularly preferred in terms of processing capacity, service life, etc. .

Gas generated in methane fermentation facilities usually has a temperature of about 35 to 55 degrees Celsius and is saturated with water, so it is heated to 40 degrees Celsius.
Hereinafter, it is preferable to cool the material to about 20.degree. C. to reduce the moisture content and then subject it to a pressure swing. Also,
Depending on the adsorbent, the temperature may be lower, followed by dehydration and drying.

In the method of the present invention, the carbon dioxide gas and methane separated by the pressure swing method are stored in appropriate pressurized tanks by a conventional method. Note that the term "methane" used in this specification means a high-calorie gas rich in methane obtained by separating carbon dioxide gas from methane fermentation gas.

The accumulated carbon dioxide is removed from the tank by appropriate means depending on the desired carbon dioxide concentration in the greenhouse, such as manually or automatically in combination with an appropriate carbon dioxide supply pipe or on-off valve, or intermittently or continuously. It is supplied into the greenhouse for a predetermined period of time. The carbon dioxide concentration in the greenhouse can be measured using a known sensor, gas detector, or the like. It depends on the target plants, etc., but normally in a greenhouse there is about 350 ppm of carbon dioxide in the natural state, but in order to promote photosynthesis, 700 ppm of carbon dioxide gas is present.
It is said that the presence of carbon dioxide gas of ~3,000 ppm is preferred. In order to maintain this carbon dioxide concentration during photosynthesis, for example, in a greenhouse with an area of 10 are and a height of 3.5 m,
When applying carbon dioxide gas for 4 hours from 8 a.m. to 12 noon on Sundays, 1 to 10 kg of carbon dioxide gas is required per hour.

On the other hand, the accumulated methane has a caloric value of, for example, 2,000-3,000 compared to the gas generated by fermentation.
It has an increase of 0 Kcal/Nm' and can be supplied to a suitable combustion device such as a burner and burned with other auxiliary fuels for heating a greenhouse if necessary. Normally, 0.5 to 0.7 kg of methane is obtained per 1 kg of carbon dioxide gas, so the obtained methane is not only used for combustion, but also used as fuel for heat engines such as gas engines and gas turbines, and used for power generation. It can be converted into various types of energy such as power, hot air, steam, hot water, and cold water, and can be used to power pressure swing devices, control weather conditions in greenhouses, etc.
It can be used for managing methane fermentation facilities and for other heating and cooling purposes.

The method of the present invention is generally implemented using the system shown in the accompanying FIG.

Namely, a methane fermentation facility! The methane fermentation gas generated is treated with a desulfurizer (not shown), etc., if necessary.
The pressure is increased to a predetermined pressure by a pressure booster 2, and the water content is reduced by cooling by a cooler 3.

The pressurized gas is introduced into an adsorption tower 4 filled with an adsorbent. The adsorption tower includes at least one tower, preferably two or more towers as shown in FIG. 1, and the pressure of the six towers is alternately varied to alternately adsorb carbon dioxide gas in the fermentation gas. The higher the number of columns, the higher the recovery rate of carbon dioxide gas, but the equipment cost also increases, so 2 to 6 columns is generally preferred. The methane from which carbon dioxide gas has been adsorbed and separated passes through the adsorption tower, is introduced into the tank 5, and is stored therein. On the other hand, the adsorbed carbon dioxide gas is desorbed by the vacuum pump 6, introduced into the tank 7, and accumulated. The carbon dioxide gas accumulated in the tank 7 is supplied into the greenhouse 8 via the supply means 9 according to the carbon dioxide concentration within the greenhouse 8 . Further, the methane accumulated in the tank 5 is sent to a burner or a heat engine 10, where it is consumed as fuel, and is used to control weather conditions such as heating and cooling in the greenhouse 8, or as an energy source for a methane fermentation facility or other purposes. The supply of carbon dioxide gas and methane is controlled by control means 11 according to desired conditions.

Thus, in another aspect of the invention, there is provided a system as shown in Figure 1 for use in carrying out the process of the invention, the system having a feed gas inlet end connected to a gas outlet end of a methane fermentation facility. At least! a pressure swing gas separation device equipped with an adsorption tower; a carbon dioxide gas tank connected to an adsorbed gas discharge end of the gas separation device and storing carbon dioxide adsorbed and separated by the device from which the gas is discharged; A methane gas tank connected to the non-adsorbed gas discharge end of the separator and accumulating the separated methane gas discharged therefrom; a supply means for supplying carbon dioxide from the carbon dioxide tank into the greenhouse; and a burner using the methane gas as fuel; It is characterized by comprising a heat engine and control means for controlling the supply of carbon dioxide gas and the weather conditions within the greenhouse.

As the pressure swing gas separation device in this system, a 2- to 6-column device as described above is preferably used, and a known pressurized tank can be used as the carbon dioxide gas or methane storage tank. As the supply means, a combination of the above-mentioned supply pipe and on-off valve or a gas supply system linked to computer control as described below can be used. Control means include, for example, temperature, humidity, gas concentration, etc. detectors placed inside the greenhouse, and depending on the detection results, the carbon dioxide supply means, greenhouse air conditioning, water supply, and other equipment are activated or stopped. It is possible to use a device that allows Such equipment may be manual or automatic and, if desired, may employ computer control.

The operating conditions of the system can be determined as appropriate depending on the target plant, the scale of the methane fermentation facility, etc.

(Example) Hereinafter, the present invention will be explained in more detail with reference to Examples.

The system used was as shown in Figure 1, and carbon dioxide and methane separated from the methane fermentation facility using the pressure swing device shown below were stored in respective storage tanks. Carbon dioxide gas was supplied to the greenhouse, and methane was used as a heat source for a hot water boiler or auxiliary boiler, and various fruits, vegetables, fruits, and flowers were cultivated in the greenhouse.

Methane fermentation facility Anaerobic fermentation facility for human waste treatment Night waste processing amount = 67-74 k12/day Methane fermentation gas generation amount: 22-27 Nm 137 hours (composition methane 65 vol.%, carbon dioxide gas 35 vol. %) Pressure swing gas separation device Carbon molecular sieve-filled two-column pressure swing gas separation device Adsorbent amount: 1002/Tower Pressure increase in booster: 2.5 kg/cm"G Fermented gas cooling temperature: 30°C Pressure swing interval = 1 minute 30 seconds Produced carbon dioxide gas Purity: 97 to 99 vol.% Production amount: 7.6 to 8.4 Nm3/hour (14.5 to 16.5 to 9/hour) Produced methane gas purity: 93 to 95 vol.% Production amount: 16.8 to 17. 4 Nm”/hourly heat 117.8
00-8.100Kcal/Nl11' Example 1 Autumn/winter melons (Earl's Favorite series, No. 3 A) were cultivated under the following conditions on a wire mesh floor in a 60-glass greenhouse (double-roofed north-south glass). .

Planting: Carbon dioxide application period on November 4th! February 2nd - January 25th Same time as above
8:00 to 14:00 (6 hours) Same concentration as above
800-1, 200ppm greenhouse temperature
When the plants were harvested one week after the application of carbon dioxide gas at 25 to 30°C and the current collection was measured, a 30% increase was observed compared to the case without application. In addition, the sugar content and net index were both good, and these results were comparable to those obtained when carbon dioxide gas was applied using a conventional cylinder method.

Meanwhile, the separated and accumulated methane gas was used as a heat source for a hot water boiler for greenhouse heating.

Example 2 Spring-harvested melons (Arus Faevolit series, No. 1 winding thread) were used for cultivation under the following conditions.

Planting February 27th Carbon dioxide application period April 16th to May 24th Same time as above
30 minutes after sunrise to 10 o'clock same concentration
900-1,1100 pI) Greenhouse temperature
Cultivation was carried out in the same manner as in Example 1 except for the above conditions at 25 to 30°C, and almost the same results as in Example 1 were obtained.

Example 3 Tomatoes were grown in a greenhouse under the following conditions.

Variety: Tanomo Greenhouse 135m” Planting: January 7th Carbon dioxide application period: January 8th to April 30th Same time as above
7:00 to 12:00 (5 hours) Same concentration as above
900 to 1,1100pp Temperature: Below 28℃ during the day in the greenhouse, above 10℃ at night Yield: 30% increase in quality Quality: Reduced hollow fruits and improved quality.

The above results were almost the same as those obtained by applying carbon dioxide gas using a cylinder method. Methane gas was also used as a heat source for greenhouse heating.

Example 4 Strawberries were grown in a greenhouse under the following conditions.

Variety: Kanmon Early Greenhouse 1201 Planting: October 16th Carbon dioxide application period: November I8th - January 17th Same time as above: 6:30 am - 4:30 pm (10 hours) Same as above concentration: 1, 200-1, 500pp
Temperature: 20-25℃ during the day in the greenhouse, 10℃ at night
℃ or higher Yield: Approximately 50% increase The above results were slightly better than when carbon dioxide gas was applied using the kerosene combustion method. Methane was also used as a heat source for heating greenhouses.

Example 5 Cucumbers were grown in a greenhouse under the following conditions.

Variety Okine overwintering greenhouse 53m2 Planted on November 13th Carbon dioxide application period November 13th to January 9th Same time as above 7:00 a.m. to 10:00 (3 hours) Same as above concentration
900~1.200ppm temperature
The greenhouse temperature was 33°C or lower during the day and 13°C or higher at night. Yield: 43% increase in total fruit number; 61% increase in total fruit weight. The above results were almost the same as when carbon dioxide gas was applied using the cylinder method. In addition, methane gas was used as a heat source for greenhouse heating.

Example 6 Separated carbon dioxide gas was applied to grapes grown in a greenhouse using a pressure swing device. However, in this example, the evaluation was not on the fruit, but on the same leaf surface of the grape using a leaf punch in the shape of a lea'' disc before (9 o'clock) and after (15 o'clock) the application of carbon dioxide gas. The photosynthetic ability was measured by punching out the leaves and comparing the dry weight of the leaves.

Variety: Muscat of Alexandria Greenhouse 165+n'' Test date: June 15th Carbon dioxide gas application time: 9:00 to 15:00 (6 hours) Same as above Concentration: 1,000 to 1,300 ppm Temperature
36-39°C As a result, the photosynthetic capacity was increased by 49% compared to the case without application of carbon dioxide gas, and almost the same result as in the case of applying carbon dioxide gas in the kerosene combustion method was obtained.

Example 7 Carnations were cultivated under the following conditions.

Variety Inbrubuto New Pink
Sim Coral Greenhouse 361 Planting October 12th Carbon dioxide application period November 1st - March 15th Same as above Time 4:00 am - 5:00 am (between IQ) Same as above Concentration 500~
700ppm Temperature: Below 16°C during the day in the greenhouse, above 10°C at night Quality: The elongated stems have become stronger due to electric lighting.

The above results were almost the same as when carbon dioxide gas was applied using a cylinder method. In addition, methane gas was used as a heat source for greenhouse heating.

(Effect of the invention) According to the present invention, in terms of safety in conventional carbon dioxide application,
In addition to solving economic problems, it is possible to effectively reuse methane fermentation gas that is released into the atmosphere as waste.

[Brief explanation of drawings]

FIG. 1 is a flow sheet showing a specific example of the greenhouse cultivation system for plants of the present invention. The main symbols in the drawings mean the following.

Claims (7)

[Claims] (1) When cultivating plants in a greenhouse, the gas generated from the methane fermentation facility is separated into carbon dioxide and methane using the pressure swing method, accumulated, and the carbon dioxide is supplied to promote photosynthesis of the plants. Featured greenhouse cultivation methods for plants. (2) Claim (1) in which the methane is used as fuel for greenhouse heating
) method described. (3) Claim No. (1) in which the methane is used as fuel for a heat engine.
) method described in section. (4) The method according to claim (3), wherein the heat engine is used to control weather conditions in a greenhouse. (5) The method according to claim (3), wherein the heat engine is used for power generation. (6) a pressure swing gas separation device equipped with at least one adsorption tower, the feed gas inlet end of which is connected to the gas discharge end of the methane fermentation facility; a carbon dioxide gas tank that stores carbon dioxide adsorbed and separated by the device, which is discharged from the gas separation device; a methane gas tank that is connected to the non-adsorbed gas discharge end of the gas separation device and stores separated methane gas that is discharged from there; It is characterized by comprising a supply means for supplying carbon dioxide gas from a gas tank into the greenhouse, a burner or heat engine that uses the methane gas as fuel, and a control means for controlling the supply of the carbon dioxide gas and the weather conditions inside the greenhouse. Plant greenhouse cultivation system. (7) The system according to claim (6), wherein the heat engine is used to control weather conditions in a greenhouse.