JP6774167B2 - Carbon dioxide-containing gas and heat supply equipment and supply method to crop production facilities - Google Patents

Description

The present invention supplies the combustion exhaust gas from a combustion furnace to a crop production facility such as a plant factory or a crop cultivation house, and applies carbon dioxide contained in the combustion exhaust gas to the crop to improve the yield and quality of the crop. The present invention relates to a carbon dioxide-containing gas and heat supply device and a supply method to a crop production facility, which enables improvement and recovers combustion heat of combustion exhaust gas and supplies heat to the crop production facility.

In crop production facilities such as plant factories and crop cultivation houses, heat obtained by burning heavy oil or kerosene is supplied as hot water or hot air for temperature control. In addition, in order to promote photosynthesis of crops, promote growth of crops, improve yield and quality, there is a carbon dioxide application technology that raises the concentration of carbon dioxide in the facility for crop production, and combustion exhaust gas obtained by burning heavy oil or kerosene. The carbon dioxide inside is supplied to the plant production facility to promote photosynthesis.

For example, in Patent Document 1, in order to control the temperature of a crop production facility and supply carbon dioxide as a fertilizer to the crop production facility, the heat obtained by burning heavy oil or kerosene is used as warm air for crop production. A carbon dioxide supply system that supplies carbon dioxide in combustion exhaust gas to a facility and stores the carbon dioxide stored in the tank to a crop production facility is disclosed. Boiler flue gas contains sulfur oxides and nitrogen oxides that adversely affect crop growth. Therefore, in the carbon dioxide supply system described in Patent Document 1, combustion exhaust gas is bubbled in a water reservoir to remove sulfur oxides, and nitrogen oxides are removed by a catalytic function of highly active carbon fibers (paragraph 0013). -See paragraph 0015).

On the other hand, utilization of biomass is required for the purpose of preventing climate change by suppressing carbon dioxide emissions, effectively using resources, and reducing the amount of waste. If biomass can be used as fuel, carbon dioxide emitted by burning fossil fuels can be eliminated, leading to further measures to prevent climate change.

Patent Document 2 describes carbon dioxide-containing gas obtained by carbonizing woody biomass and burning the decomposition gas to generate power while using the heat obtained by burning the decomposition gas. A carbon dioxide supply system that supplies crop production facilities and promotes crop growth is disclosed (see paragraphs 0019 to 0023).

In Patent Document 3, biomass is burned in a vertical furnace, the heat obtained by burning the biomass is supplied to a facility for crop production, and the carbon dioxide-containing gas obtained by burning the biomass is used as a crop. The carbon dioxide supply system that supplies the production facility is disclosed. Combustion exhaust gas burned using biomass as fuel contains sulfur oxides and nitrogen oxides that adversely affect the growth of crops. In the carbon dioxide supply system described in Patent Document 3, harmful components such as sulfur oxides and nitrogen oxides in the combustion exhaust gas are preliminarily washed off with a scrubber, and further, combustion exhaust gas treatment for adsorbing and removing them with a porous adsorbent is performed. The treated flue gas is supplied to the crop production facility (see paragraphs 0041 to 0044).

Japanese Unexamined Patent Publication No. 2012-16322 Japanese Unexamined Patent Publication No. 2006-191876 International Publication No. 2009/038103

However, biomass combustion exhaust gas contains not only sulfur oxides and nitrogen oxides, but also ethylene, which is harmful to crop growth, and carbon monoxide, which is harmful to workers in crop production facilities. Ethylene causes buds to fall off, leaves and flowers to grow poorly, and promotes crop ripening, resulting in a situation in which the crop at harvest is too ripe to be shipped. Carbon monoxide also causes poisoning of workers working in crop production facilities. Large-scale incinerators equipped with a secondary combustion chamber can sufficiently remove carbon monoxide, but small-scale incinerators often do not have a secondary combustion chamber, and removal of carbon monoxide is an issue. ..

The present invention has been made in view of the above circumstances, and has been purified by removing sulfur oxides, nitrogen oxides, carbon monoxide and ethylene that are harmful to crops in the exhaust gas produced by burning fuel. An object of the present invention is to provide a supply device and a supply method for supplying carbon dioxide-containing gas and heat to a crop production facility capable of supplying exhaust gas to a crop production facility as a carbon dioxide-containing gas that promotes plant growth. It is a thing.

One aspect of the present invention is a supply device that supplies carbon dioxide-containing gas and heat to a facility for crop production, and heat is generated by heat exchange between a combustion furnace that burns fuel and combustion exhaust gas discharged from the combustion furnace. A heat exchanger that supplies heat to the facility for crop production, a sulfur oxide remover that blows sodium bicarbonate powder into the combustion exhaust gas to generate a reaction product with the sulfur oxide contained in the combustion exhaust gas, and combustion. A dust collector that collects soot and dust contained in the exhaust gas and collects the reaction products, and a nitrogen oxide removal device that blows ammonia gas into the combustion exhaust gas and decomposes the nitrogen oxides contained in the combustion exhaust gas by a denitration catalyst. Equipment, carbon monoxide and ethylene removal equipment that oxidizes and removes carbon monoxide and ethylene contained in combustion exhaust gas with an oxidation catalyst, and purification gas supply equipment that supplies purified combustion exhaust gas to crop production facilities. the provided, in order from the upstream side of the combustion exhaust gas flows, said sulfur oxide removal device, the dust collection unit, the nitrogen oxide removal device, the carbon monoxide and ethylene removal device is arranged, the carbon monoxide and The circulating gas discharged from the ethylene removing device is heated by a gas heating device and returned to the upstream side of the carbon monoxide and ethylene removing device and the downstream side of the nitrogen oxide removing device, and the carbon monoxide and ethylene removing device. It is a carbon dioxide-containing gas and heat supply device that removes tar mist adhering to the oxidation catalyst .

Another aspect of the present invention is a method of supplying carbon dioxide-containing gas and heat to a facility for crop production, in which heat between a step of burning fuel in a combustion furnace and combustion exhaust gas discharged from the combustion furnace is used. The process of obtaining heat by exchange and supplying heat to the facility for crop production, and the process of blowing sodium bicarbonate powder into the combustion exhaust gas to remove the sulfur oxide that produces a reaction product with the sulfur oxide contained in the combustion exhaust gas. The oxide removal step, the dust collection step of collecting soot and dust contained in the combustion exhaust gas and collecting the reaction product, and the nitrogen oxide contained in the combustion exhaust gas by blowing ammonia gas into the combustion exhaust gas and using a denitration catalyst. A carbon monoxide and ethylene removal process that oxidizes and removes carbon monoxide and ethylene contained in combustion exhaust gas with an oxidation catalyst, and supplies purified combustion exhaust gas to a facility for crop production. The purification gas supply step is provided, and the sulfur oxide removal step, the dust collection step, the nitrogen oxide removal step, and the carbon monoxide and ethylene removal steps are carried out in order from the upstream side through which the combustion exhaust gas flows. Then, the circulating gas discharged in the carbon monoxide and ethylene removal step is heated by a gas heating device and returned to the upstream side of the carbon monoxide and ethylene removal step and the downstream side of the nitrogen oxide removal step. It is a method of supplying carbon dioxide-containing gas and heat for removing tar mist adhering to the oxidation catalyst used in the step of removing carbon monoxide and ethylene.

According to the present invention, sulfur oxides, nitrogen oxides, carbon monoxide, and ethylene in combustion exhaust gas can be efficiently removed. By supplying combustion exhaust gas that does not adversely affect the growth of crops, it is possible to provide plants with carbon dioxide that is effective in promoting the growth of crops. In addition, heat can be recovered from the combustion exhaust gas and used for temperature control in a crop production facility. Furthermore, the catalytic activity of the oxidation catalyst of the carbon monoxide and ethylene removing device can be restored.

Schematic diagram of the carbon dioxide-containing gas and heat supply device according to the first embodiment of the present invention. Schematic diagram showing the supply device of FIG. 1 with a control system added. Schematic diagram of the carbon dioxide-containing gas and heat supply device according to the second embodiment of the present invention.

Hereinafter, the carbon dioxide-containing gas and heat supply device (hereinafter, simply referred to as a supply device) according to the first embodiment of the present invention will be described in detail with reference to FIG. The supply device supplies carbon dioxide-containing gas and heat to the crop production facility 11 such as a plant factory or a crop cultivation house, and the combustion furnace 1, the heat exchanger 2, and the sulfur oxide removing device 3 are in order from the upstream side. , A dust collecting device 4, a nitrogen oxide removing device 5, a carbon monoxide and ethylene removing device 8, and a purifying gas supply device 9. Hereinafter, each component will be described in order.

(Combustion furnace)
The combustion furnace 1 receives the supply of biomass, burns the biomass, and emits exhaust gas. As the biomass, wood-based biomass (for example, wood chips, wood chips, thinned wood, lumber waste, construction waste, etc.) is used. A typical combustion furnace 1 is a grate type combustion furnace, and has a combustion chamber having a grate, a supply port for supplying biomass on the grate, and a blower for supplying combustion air to the combustion chamber. Be prepared. A grate-type combustion furnace that supplies combustion air to the biomass on the grate and burns it is preferable because of its high combustion efficiency, but the furnace type is not limited to this.

(Heat exchanger)
The heat exchanger 2 heats water by heat exchange between the combustion exhaust gas of the combustion furnace 1 (hereinafter, simply referred to as exhaust gas) and water to obtain hot water, and heats for heating and temperature control is used in the crop production facility 11. Supply to. The heat exchanger 2 and the crop production facility 11 are connected by a hot water pipe 12 to supply hot water. By storing the hot water obtained in the heat exchanger 2 in a heat storage tank separately provided, it is possible to supply heat more effectively in response to the heat demand of the crop production facility 11. For example, hot water obtained and stored in the daytime (heat stored) can be used at night when heat demand is high, and flexible measures can be taken.

The heat exchanger 2 may obtain steam by heat exchange between exhaust gas and water and supply the steam to the crop production facility 11, or send the steam to a steam turbine to generate electricity by the steam turbine to generate electric energy. It may be supplied to the crop production facility 11. Further, a combustion boiler in which the combustion furnace 1 and the heat exchanger 2 are integrated may be used, or a combustion furnace 1 and a heat exchanger 2 may be separated from each other.

The exhaust gas from the combustion furnace 1 contains sulfur oxides, nitrogen oxides, carbon monoxide, and ethylene that are harmful to crops or workers. Sulfur oxides (SO _x ) and nitrogen oxides (NO _x ) are causative substances of air pollution, adversely affect the growth of plants, and are harmful to workers working in the crop production facility 11. Carbon monoxide (CO) causes carbon monoxide poisoning to workers. Ethylene causes poor growth of crops and overripe crops. Therefore, these harmful substances are removed by the following sulfur oxide removing device 3, nitrogen oxide removing device 5, carbon monoxide and ethylene removing device 8.

(Sulfur oxide remover)
The sulfur oxide removing device 3 includes a baking soda blowing device that blows baking soda (sodium hydrogen carbonate) powder into the exhaust gas heat recovered by the heat exchanger 2. The baking soda blowing device includes a baking soda storage tank for storing baking soda, a cutting device for cutting out baking soda powder from the baking soda storage tank, and a nozzle for blowing the cut out baking soda powder into exhaust gas together with compressed air. The nozzle is arranged in the duct 13 on the downstream side of the heat exchanger 2 and on the upstream side of the dust collector 4.

The baking soda powder blown into the exhaust gas reacts with sulfur oxides (SO _x ) to produce sodium sulfate (Na ₂ SO ₄ ) as a reaction product. The reaction formula of sulfur oxide (SOx) and baking soda powder (NaHCO ₃ ) is as shown in Formula 1.
(Equation 1)
2NaHCO ₃ + SO ₂ + 1 / 2O ₂ → Na ₂ SO ₄ + H ₂ O + 2CO ₂

The reaction product particles (Na ₂ SO ₄ ) are collected together with the dust by the dust collector 4, and the sulfur oxides are removed from the exhaust gas. The temperature at which the sulfur oxide is removed by the reaction with the baking soda powder is preferably 170 to 200 ° C. in order to increase the reaction efficiency. The heat exchange by the heat exchanger 2 is controlled so that the exhaust gas temperature is within this range.

(Dust collector)
The dust collector 4 collects dust contained in the exhaust gas and also collects reaction product particles of baking soda powder and sulfur oxide (SO _x ). It is preferable to use a filtration type dust collector such as a bag filter because the efficiency of collecting the reaction product particles of dust and sulfur oxide is high. Unreacted baking soda powder adhering to the filter surface of the bag filter also reacts with sulfur oxides.

(Nitrogen oxide remover)
The nitrogen oxide removing device 5 includes an ammonia supply device 6 for blowing ammonia gas into the exhaust gas from which dust has been removed by the dust collecting device 4, and a denitration catalyst device 7 containing a denitration catalyst. The denitration catalyst device 7 decomposes nitrogen oxides (NO _x ) into N ₂ and H ₂ O by reaction with ammonia to remove nitrogen oxides. The reaction formula between ammonia (NH ₃ ) and nitrogen oxide (NO _x ) is as shown in Formula 2.
(Equation 2)
4NO + 4NH ₃ + O ₂ → 4N ₂ + 6H ₂ O
NO + NO ₂ + 2NH ₃ → 2N ₂ + 3H ₂ O

The denitration catalyst is not limited, but a catalyst using TiO ₂ as a carrier and V ₂ O ₂ , WO _3, etc. as an active agent is preferable, and the catalyst shape may be a honeycomb-shaped or plate-shaped parallel flow type having a small pressure loss. preferable. The temperature at which nitrogen oxides are removed by ammonia gas and a denitration catalyst is not particularly limited, but operating in the temperature range of 170 to 200 ° C., which is the temperature at which sulfur oxides are removed, does not require reheating. preferable. A suitable denitration catalyst should be used in this temperature range.

(Carbon monoxide and ethylene remover)
The carbon monoxide and ethylene removal device 8 introduces the exhaust gas from which nitrogen oxides have been removed by the nitrogen oxide removal device 5 into an oxidation catalyst device containing an oxidation catalyst, and oxidizes carbon monoxide and ethylene by the action of the catalyst. Then, make it a substance such as CO ₂ , H ₂ O that is harmless to crops or workers. The oxygen used for oxidation is oxygen contained in the exhaust gas. Since the combustion air is blown into the combustion furnace 1, sufficient oxygen is present in the exhaust gas. The oxidation catalyst is not limited, but it is preferable to use a catalyst in which platinum or rhodium is supported on the carrier. The temperature at which carbon monoxide and ethylene are oxidized and removed by an oxidation catalyst is not particularly limited, but it is necessary to perform reheating by operating in the temperature range of 170 to 200 ° C., which is the temperature at which sulfur oxides are removed. It is preferable because it does not exist. Use a suitable oxidation catalyst in this temperature range.

The arrangement of the nitrogen oxide removing device 5 and the carbon monoxide and ethylene removing device 8 may be in the order shown in FIG. 1 or in the reverse order. That is, the carbon monoxide and ethylene removing device 8 can be arranged on the upstream side, and the nitrogen oxide removing device 5 can be arranged on the downstream side.

By installing the nitrogen oxide removing device 5 and the carbon monoxide and ethylene removing device 8 on the downstream side of the dust collecting device 4, the denitration catalyst and the poisonous component for the oxidation catalyst contained in the combustion exhaust gas of biomass are collected. It can be removed in advance in 4.

(Purification gas supply device)
The purified gas supply device 9 supplies the combustion exhaust gas purified by the removal devices 3, 4, 5, and 8 to the crop production facility 11. The purification gas supply device 9 includes a heat exchanger 10. The exhaust gas from which carbon monoxide and ethylene have been removed by the carbon monoxide and ethylene removing device 8 is cooled by the heat exchanger 10 to, for example, 100 to 130 ° C., further diluted with air, and cooled to, for example, 30 to 50 ° C. It is supplied as carbon dioxide-containing gas to the crop production facility 11. By setting the temperature of the carbon dioxide-containing gas to a temperature close to room temperature, the crops in the crop production facility 11 are not adversely affected. The heat exchanger 10 may heat water by heat exchange between purified gas and water to obtain hot water, and supply heat for heating and temperature control to the crop production facility 11.

A supply device equipped with a device for each of the above components can efficiently remove sulfur oxides, nitrogen oxides, carbon monoxide, and ethylene that are harmful to the crop or workers in the combustion exhaust gas, which adversely affects the growth of the crop. It is possible to supply carbon dioxide, which is effective in promoting the growth of crops, to plants by supplying the combustion exhaust gas that has never been used to the crop production facility 11, and further, heat is recovered from the combustion exhaust gas, and the inside of the crop production facility 11 Can supply heat to.

In addition, a control system for controlling the operation of the crop production facility 11 and the supply device is provided to start and stop the supply device and burn fuel during operation according to the carbon dioxide demand and heat demand of the crop production facility 11. The amount may be controlled. For example, the control system may activate the supply device or increase the amount of fuel burned to meet the demand when it is determined that more carbon dioxide or heat is needed in the crop production facility 11. Control.

FIG. 2 shows a configuration diagram of a supply device to which a control system for suppressing the concentration of harmful substances contained in exhaust gas is added. The configurations of the combustion furnace 1, the heat exchanger 2, the sulfur oxide removing device 3, the dust collecting device 4, the nitrogen oxide removing device 5, the carbon monoxide and ethylene removing device 8, and the purification gas supply device 9 are shown in FIG. Since it is the same as the one shown, the same reference numerals are given and the description thereof will be omitted.

A gas component concentration meter 21 for measuring the component concentration of the purified gas is arranged on the downstream side of the carbon monoxide and ethylene removal device 8. The control device 22 controls the amount of baking soda supplied by the sulfur oxide removing device 3 based on the measured value of the sulfur oxide of the gas component concentration meter 21. For example, the control device 22 increases the baking soda supply amount when the measured value of the sulfur oxide of the gas component concentration meter 21 is higher than a predetermined allowable range value, and decreases the baking soda supply amount when it is low. ..

The control device 22 controls the amount of ammonia gas supplied by the nitrogen oxide removing device 5 based on the measured value of the nitrogen oxide of the gas component concentration meter 21. For example, the control device 22 increases the amount of ammonia gas supplied when the measured value of nitrogen oxides of the gas component concentration meter 21 is higher than a predetermined allowable range value, and increases the amount of ammonia gas supplied when the measured value is lower than a predetermined allowable range value. Reduce.

The duct that sends the purified gas discharged from the carbon monoxide and ethylene removal device 8 to the heat exchanger 10 is a circulation flow path that branches and returns a part of the purified gas to the upstream side of the carbon monoxide and ethylene removal device 8. 23 is provided, and a regulating valve 24 for adjusting the amount of circulating gas to be returned is arranged. By returning a part of the purification gas to the upstream side of the carbon monoxide and ethylene removal device 8, the carbon monoxide and ethylene remaining in the purification gas are brought into contact with the oxidation catalyst again, and the concentration of carbon monoxide and ethylene is lowered. Remove up to. The control device 22 adjusts the opening degree of the adjusting valve 24 based on the measured values of carbon monoxide and ethylene of the gas component concentration meter 21, and controls the amount of circulating gas. For example, the control device 22 increases the amount of circulating gas when the measured values of the carbon monoxide and ethylene removal device 8 of the gas component concentration meter 21 are equal to or higher than a predetermined threshold value for a certain period of time or longer. Further, the control device 22 determines the replacement time of the oxidation catalyst of the carbon monoxide and ethylene removal device 8 based on the measured values of carbon monoxide and ethylene of the gas component concentration meter 21. For example, the control device 22 displays an alarm prompting the replacement of the oxidation catalyst when the measured values of the carbon monoxide and ethylene removal device 8 of the gas component concentration meter 21 are equal to or higher than a predetermined threshold value for a certain period of time or longer.

In the supply device to which the control system shown in FIG. 2 is added, a gas component concentration meter 21 for measuring the component concentration of the purified gas is arranged on the downstream side of the carbon monoxide and ethylene removal device 8 and controlled by the control device 22. However, a gas component concentration meter 21 for measuring the concentration of various gas components in the crop production facility 11 may be arranged to measure and control the gas component concentration meter 21. That is, based on the measured values of the concentrations of various gas components in the crop production facility 11, the amount of sodium bicarbonate supplied by the sulfur oxide removing device 3, the amount of ammonia gas supplied by the nitrogen oxide removing device 5, and a part of the purified gas are carbon monoxide. It is also possible to control the amount of circulating gas returned to the upstream side of the carbon and ethylene removing device 8 to control the gas purification device of the supply device according to the operating status of the crop production facility 11.

FIG. 3 is a schematic view of a carbon dioxide-containing gas and heat supply device (hereinafter, simply referred to as a supply device) according to the second embodiment of the present invention. The configurations of the combustion furnace 1, the heat exchanger 2, the sulfur oxide removing device 3, the dust collecting device 4, the nitrogen oxide removing device 5, the carbon monoxide and ethylene removing device 8, and the purification gas supply device 9 are shown in FIG. Since it is the same as the one, the same reference numerals are given and the description thereof will be omitted.

In the supply device of the second embodiment, the denitration catalyst of the denitration catalyst device 7 and the catalytic activity recovery means for recovering the catalytic activity by removing the tar mist adhering to the carbon monoxide and the oxidation catalyst of the ethylene removal device 8 are provided. The added point is different from the supply device of the first embodiment. The catalytic activity recovery means includes a circulation flow path 31 and a gas heating device 32.

The reason for adding the catalytic activity recovery means is as follows. Most of the tar generated by the biomass combustion in the combustion furnace 1 is removed by the dust collector 4, but as the exhaust gas flows from the dust collector 4 to the denitration catalyst device 7, carbon monoxide and ethylene removal device 8, the exhaust gas is exhausted. The temperature drops below the dew point of the gaseous tar, and the gaseous tar liquefies to generate a small amount of tar mist. When this tar mist adheres to the denitration catalyst of the denitration catalyst device 7 and the oxidation catalyst of the carbon monoxide and ethylene removal device 8, these catalytic activities decrease.

As a method for removing tar mist adhering to the catalyst, it is known that tar is removed by removing the catalyst from the catalyst device and air-baking the catalyst in a heating furnace. However, it is complicated to put the catalyst in and out of the catalyst device, and it is necessary to stop the catalyst device for a certain period of time, so that it cannot be said to be a desirable removal method.

On the other hand, as a result of investigating the morphology of the trace amount of tar mist generated as described above in detail, the inventor has found that the morphology is relatively easy to remove even if it adheres to the catalyst. Therefore, the inventor has devised a catalyst activity recovery means that does not require the catalyst to be removed from the catalyst device. That is, in the present embodiment, a part of the purification gas discharged from the carbon monoxide and ethylene removing device 8 is heated by the gas heating device 32, and the upstream side of the denitration catalyst device 7 and the carbon monoxide and ethylene removing device Returning to the upstream side of 8, the denitration catalyst of the denitration catalyst device 7 and the oxidation catalyst of the carbon monoxide and ethylene removal device 8 are heated. As a result, tar mist adhering to the denitration catalyst and the oxidation catalyst is volatilized and removed, and the catalytic activity of these is restored.

Specifically, the duct that sends the purified gas discharged from the carbon monoxide and the ethylene removing device 8 to the heat exchanger 10 is branched, and a part of the purified gas is transferred to the upstream side of the denitration catalyst device 7 and carbon monoxide. And a circulation flow path 31 for returning to the upstream side of the ethylene removing device 8 is provided. Then, a gas heating device 32 for heating a part of the purified gas (hereinafter referred to as circulating gas) is arranged in the circulation flow path 31. The circulating gas heated by the gas heating device 32 heats the denitration catalyst of the denitration catalyst device 7 and the oxidation catalyst of the carbon monoxide and ethylene removal device 8, thereby removing tar mist adhering to the denitration catalyst and the oxidation catalyst. Volatilize and remove.

As the gas heating device 32, an electric heater type gas heating device is preferable. When an electric heater type gas heating device is used as the gas heating device, reaction air is supplied as needed to burn the tar contained in the circulating gas by volatilizing from the catalyst, and the tar is burned.

The temperature for raising the temperature of the denitration catalyst and the oxidation catalyst is preferably in the temperature range of 160 to 500 ° C, and more preferably in the temperature range of 180 to 300 ° C. This is because in order to volatilize and remove the adhering tar mist, it is necessary to set the temperatures of the denitration catalyst and the oxidation catalyst to a temperature equal to or higher than the operating temperature of the dust collector 4 and higher than the dew point of the tar mist.

When a decrease in the catalytic activity of the denitration catalyst and / or the oxidation catalyst is observed, an operation of returning the heated circulating gas is performed to restore the catalytic activity. According to the present embodiment, even during the operation of the denitration catalyst device 7 and the carbon monoxide and ethylene removal device 8, the catalytic activity recovery operation can be performed without stopping each device. Of course, the catalytic activity recovery operation can be performed even when each device is stopped.

(Example)
Examples of the present invention will be described below in comparison with Comparative Examples. When the exhaust gas discharged from the combustion furnace is supplied to the crop production facility, the allowable upper limit concentration of the components in the exhaust gas that does not adversely affect the growth of the crop is set as shown in Table 1 below.

Comparative example

An experiment was conducted in which wood chips were burned in a combustion furnace. The wood chips had a water content of 30% and a size of 3 to 10 cm, and were supplied to a combustion furnace at a supply amount of 120 kg / hr and burned.

The exhaust gas was sent to a heat exchanger integrated with the combustion furnace, cooled to about 180 ° C., and hot water of about 85 ° C. was obtained by heat exchange with water. The amount of exhaust gas generated was about 1200 Nm ³ / hr, and the amount of heat obtained as hot water was about 280 KW.

The cooled exhaust gas was removed with a cyclone type dust collector.

The results of component measurement in the dust-removed exhaust gas are shown in Table 2 below.

As shown in Table 2, the concentrations of sulfur oxides, nitrogen oxides, and ethylene contained in the exhaust gas are all equal to or higher than the allowable upper limit concentration that can be supplied to the crop production facility, and if they are supplied as they are, the growth of crops will be adversely affected.

The wood chips were burned in the same manner as in the comparative example, and the exhaust gas removed by the cyclone type dust collector was further subjected to the following treatment.

Baking soda powder was supplied and mixed with the exhaust gas at about 180 ° C. removed by a cyclone type dust collector at a supply amount of 40 g / hr, and the reaction product and soot dust were removed by a bag filter. Next, ammonia gas was supplied and mixed with the exhaust gas at a supply amount of 1 L / min, and the space velocity (SV value) was supplied to the denitration catalyst device at 4100 / hr. A catalyst containing vanadium and tungsten was used as the denitration catalyst. Further, the exhaust gas was supplied to the oxidation catalyst device at a space velocity (SV value) of 22000 / hr. A catalyst containing platinum was used as the oxidation catalyst.

Table 3 shows the component measurement results in the exhaust gas after the above treatment.

As shown in Table 3, all of sulfur oxides, nitrogen oxides, and ethylene have been reduced to below the permissible upper limit concentration that can be supplied to crop production facilities, and crop growth is promoted without adversely affecting crop growth. It is possible to provide crops with carbon dioxide that is effective for crops. The concentration of carbon monoxide was also reduced to 25 ppm or less, which does not adversely affect the operator. By diluting the exhaust gas after purification treatment and supplying it to the crop production facility, it is possible to supply carbon dioxide-containing gas that does not adversely affect the crops and workers.

1 ... Combustion furnace 2 ... Heat exchanger 3 ... Sulfur oxide removing device 4 ... Dust collecting device 5 ... Nitrogen oxide removing device 6 ... Ammonia supply device 7 ... Denitration catalyst device 8 ... Carbon monoxide and ethylene removing device 9 ... Purification Gas supply device 10 ... Heat exchanger 12 ... Hot water pipe 13 ... Duct 21 ... Gas component concentration meter 22 ... Control device 23 ... Circulation flow path 24 ... Adjustment valve 31 ... Circulation flow path 32 ... Gas heating device

Claims (4)

A supply device that supplies carbon dioxide-containing gas and heat to crop production facilities.
A combustion furnace that burns fuel and
A heat exchanger that obtains heat by heat exchange with the combustion exhaust gas discharged from the combustion furnace and supplies heat to the facility for crop production.
A sulfur oxide removing device that blows sodium bicarbonate powder into the combustion exhaust gas to generate a reaction product with the sulfur oxide contained in the combustion exhaust gas.
A dust collector that collects soot and dust contained in combustion exhaust gas and collects the reaction products.
A nitrogen oxide remover that blows ammonia gas into the combustion exhaust gas and decomposes the nitrogen oxides contained in the combustion exhaust gas with a denitration catalyst.
A carbon monoxide and ethylene removal device that oxidizes and removes carbon monoxide and ethylene contained in combustion exhaust gas with an oxidation catalyst.
Equipped with a purified gas supply device that supplies purified combustion exhaust gas to crop production facilities,
The sulfur oxide removing device, the dust collecting device, the nitrogen oxide removing device, the carbon monoxide and the ethylene removing device are arranged in order from the upstream side where the combustion exhaust gas flows.
The circulating gas discharged from the carbon monoxide and ethylene removing device is heated by a gas heating device and returned to the upstream side of the carbon monoxide and ethylene removing device and the downstream side of the nitrogen oxide removing device, and the monoxide is oxidized. A carbon dioxide-containing gas and heat supply device that removes tar mist adhering to the oxidation catalyst of the carbon and ethylene removing device. The carbon dioxide-containing gas and heat supply device according to claim 1, wherein the purified gas supply device includes a heat exchanger for cooling the purified gas. A supply method that supplies carbon dioxide-containing gas and heat to crop production facilities.
The process of burning fuel in a combustion furnace and
The process of obtaining heat by heat exchange with the combustion exhaust gas discharged from the combustion furnace and supplying heat to the crop production facility, and
A sulfur oxide removal step in which sulfur oxide powder is blown into the combustion exhaust gas to remove the sulfur oxide that produces a reaction product with the sulfur oxide contained in the combustion exhaust gas.
A dust collection process that collects soot and dust contained in combustion exhaust gas and collects the reaction products.
A nitrogen oxide removal step in which ammonia gas is blown into the combustion exhaust gas and the nitrogen oxides contained in the combustion exhaust gas are decomposed by a denitration catalyst.
Carbon monoxide and ethylene removal steps that oxidize and remove carbon monoxide and ethylene contained in combustion exhaust gas with an oxidation catalyst,
It is equipped with a purified gas supply process that supplies purified combustion exhaust gas to crop production facilities.
The sulfur oxide removing step, the dust collecting step, the nitrogen oxide removing step, and the carbon monoxide and ethylene removing steps are carried out in order from the upstream side where the combustion exhaust gas flows.
The circulating gas discharged in the carbon monoxide and ethylene removal step is heated by a gas heating device and returned to the upstream side of the carbon monoxide and ethylene removal step and the downstream side of the nitrogen oxide removal step , and the monoxide is oxidized. A method for supplying carbon dioxide-containing gas and heat for removing tar mist adhering to the oxidation catalyst used in the carbon and ethylene removal step . The method for supplying carbon dioxide-containing gas and heat according to claim 3, wherein the purified gas supply step includes a heat exchange step for cooling the purified gas.

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