JP2018138496A - Fertilizer production apparatus, and fertilizer production method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve efficiency of producing a nitrogen fertilizer.SOLUTION: A fertilizer production apparatus 100 comprises a combustion part 130 that at least burns ammonia to generate flue gas and a recovery part 200 that recovers nitrogen oxides from the flue gas to produce a nitrogen fertilizer. BY burning ammonia, fuel NOx as well as thermal NOx can be generated and the content of NOx in the flue gas can be increased. Accordingly, the efficiency of producing a nitrogen fertilizer can be improved by producing a nitrogen fertilizer from the flue gas.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a fertilizer manufacturing apparatus that manufactures a fertilizer composed of a nitrogen compound, and a fertilizer manufacturing method.

  In recent years, cogeneration systems capable of generating and supplying heat have been developed. For example, Patent Document 1 describes a cogeneration system including a diesel engine, a generator, an exhaust gas heat utilization device, and an exhaust gas treatment device.

  The diesel engine burns light oil. The generator is driven by a diesel engine. The exhaust gas heat utilization device recovers heat from the exhaust gas discharged from the diesel engine. The exhaust gas treatment device collects nitrogen oxides (NOx) from the exhaust gas discharged from the exhaust gas heat utilization device to produce nitrogen fertilizer.

JP 2003-201808 A

  Since NOx is an air pollutant, its emission amount is regulated. For this reason, a mechanism for preventing NOx from being generated as much as possible is attached to a diesel engine that burns light oil. Therefore, in the technique of Patent Document 1, the amount of NOx contained in the exhaust gas discharged from the diesel engine is extremely small.

Even if the mechanism is removed, NOx generated by burning light oil is generated by the reaction of nitrogen (N ₂ ) and oxygen (O ₂ ) contained in combustion air, so-called Thermal NOx. For this reason, there is a limit in increasing the NOx content in the exhaust gas. Therefore, there is a problem that the production efficiency of nitrogen fertilizer is low from the viewpoint of production of nitrogen fertilizer.

  In view of such problems, an object of the present invention is to provide a fertilizer manufacturing apparatus and a fertilizer manufacturing method capable of improving the manufacturing efficiency of nitrogen fertilizer.

  In order to solve the above-described problems, a fertilizer manufacturing apparatus according to the present invention includes a combustion unit that burns at least ammonia to generate combustion exhaust gas, and a recovery unit that recovers nitrogen oxides from the combustion exhaust gas to produce nitrogen fertilizer. And comprising.

  The combustion unit may co-fire the ammonia and fuel.

  The fuel may be one or more of hydrocarbon, hydrogen, waste plastic fuel, and wood fuel.

  The combustion unit may burn the ammonia with a gas having a higher oxygen content than air.

  In order to solve the above problems, a method for producing a fertilizer according to the present invention includes a step of combusting at least ammonia to generate combustion exhaust gas, a step of recovering nitrogen oxide from the combustion exhaust gas, and producing nitrogen fertilizer, including.

  According to the present invention, it is possible to improve the production efficiency of nitrogen fertilizer.

It is a figure explaining a fertilizer manufacturing apparatus. It is a flowchart explaining the flow of a process of the fertilizer manufacturing method. It is a figure explaining a simulation condition and a simulation result.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in the embodiments are merely examples for facilitating the understanding of the invention, and do not limit the present invention unless otherwise specified. In the present specification and drawings, elements having substantially the same function and configuration are denoted by the same reference numerals, and redundant description is omitted, and elements not directly related to the present invention are not illustrated. To do.

(Fertilizer manufacturing apparatus 100)
FIG. 1 is a diagram illustrating a fertilizer manufacturing apparatus 100 according to this embodiment. As shown in FIG. 1, the fertilizer production apparatus 100 includes an ammonia supply unit 110, a premixer 120, a combustion unit 130, a gas turbine 140, a compressor 150, a boiler 160, a steam turbine 170, and power generation. Machine 180, condenser 190, feed water pump 192, and recovery unit 200. In FIG. 1, the flow of ammonia, fuel, air, exhaust gas, and water is indicated by solid arrows.

  The ammonia supply unit 110 supplies ammonia to the premixer 120. The ammonia supply unit 110 includes a storage unit 112, a vaporizer 114, and a pressure pump 116. The storage part 112 is comprised with a tank, for example, and stores ammonia (liquid). The vaporizer 114 is supplied with liquid ammonia stored in the storage unit 112. The vaporizer 114 heats and vaporizes liquid ammonia. The pressure pump 116 supplies the ammonia vaporized by the vaporizer 114 to the premixer 120.

  The premixer 120 mixes the ammonia (gas) supplied by the pressure pump 116 and the fuel and supplies the fuel to the combustion unit 130. The fuel is, for example, natural gas.

  A premixed mixture of ammonia and fuel is supplied to the combustion unit 130 by a pressure pump 116. The combustion section 130 is supplied with oxygen-enriched gas by a compressor 150 described later. The oxygen-enriched gas is a gas having a higher oxygen content than air. The combustion unit 130 co-fires ammonia and fuel with oxygen-enriched gas to generate combustion exhaust gas. When the combustion unit 130 burns ammonia, not only thermal NOx but also fuel-derived so-called fuel NOx is generated. Therefore, when the combustion unit 130 burns ammonia, the NOx content in the combustion exhaust gas can be increased as compared with the case where fossil fuel such as light oil and natural gas is burned.

  Moreover, the combustion part 130 co-fires fuel with ammonia, so that the combustion efficiency (oxidation efficiency) of ammonia can be improved. Therefore, it becomes possible to increase the NOx content in the combustion exhaust gas.

  In addition, when the combustion unit 130 burns ammonia with the oxygen-enriched gas, the combustion efficiency of ammonia can be improved as compared with the case of burning with air. Thereby, it becomes possible to increase the NOx content rate in the combustion exhaust gas.

  The gas turbine 140 rotates the rotating shaft 142 with the combustion exhaust gas generated by the combustion unit 130. The compressor 150 is connected to the rotation shaft 142 of the gas turbine 140, and compresses (pressure-increases) the oxygen-enriched gas by the rotation of the rotation shaft 142 and supplies it to the combustion unit 130. The boiler 160 is supplied with the combustion exhaust gas that has passed through the gas turbine 140. The boiler 160 includes a pipe 162 and heats water passing through the pipe 162 with combustion exhaust gas to generate water vapor. The steam turbine 170 rotates the rotating shaft 172 with the steam generated by the boiler 160. The generator 180 is connected to the rotating shafts 142 and 172, and generates electricity by the rotation of the rotating shafts 142 and 172. The condenser 190 cools and condenses the water vapor that has passed through the steam turbine 170. The water supply pump 192 supplies the water condensed by the condenser 190 to the pipe 162.

The recovery unit 200 recovers NOx (nitrogen oxide) from the combustion exhaust gas to produce fertilizer. The collection unit 200 includes a preprocessing unit 210 and an adsorption unit 220. For example, the pretreatment unit 210 is configured to include a carrier on which an oxidation catalyst is supported, and oxidizes nitrogen monoxide (NO) in NOx contained in the combustion exhaust gas to generate nitrogen dioxide (NO ₂ ). Further, the pretreatment unit 210 removes moisture from the combustion exhaust gas. Further, the pretreatment unit 210 removes gases other than NOx (for example, carbon dioxide (CO ₂ )) from the combustion exhaust gas.

The adsorption unit 220 adsorbs the combustion exhaust gas processed by the pretreatment unit 210 on the adsorbent. Here, the adsorbent is, for example, slag or activated carbon. The adsorbent adsorbed with NO ₂ can be used as it is as a fertilizer. For example, it is possible to transport the adsorbent produced in this way and adsorbed with NO ₂ to farmland, cultivation house, plant factory, etc. and fertilize as it is.

(Fertilizer manufacturing method)
Then, the fertilizer manufacturing method using the said fertilizer manufacturing apparatus 100 is demonstrated. FIG. 2 is a flowchart for explaining the processing flow of the fertilizer manufacturing method.

(Step S110: Premixed gas generation step)
The ammonia supply unit 110 supplies ammonia to the premixer 120, and a supply unit (not shown) supplies fuel to the premixer 120. The premixer 120 generates a premixed gas of ammonia and fuel.

(Step S120: Combustion exhaust gas generation process)
The combustion unit 130 burns the premixed gas generated in step S110 to generate combustion exhaust gas.

(Step S130: Fertilizer manufacturing process)
The recovery unit 200 recovers NOx from the combustion exhaust gas generated in step S120 and manufactures fertilizer.

  As explained above, since the fertilizer manufacturing apparatus 100 of this embodiment burns ammonia and produces | generates combustion exhaust gas, it can produce | generate not only thermal NOx but fuel NOx. Thereby, it becomes possible to increase the content rate of NOx as compared with the combustion exhaust gas generated as a result of burning fossil fuel. Therefore, nitrogen fertilizer can be produced from combustion exhaust gas having a relatively high NOx content, and the production efficiency of nitrogen fertilizer can be improved.

  Ammonia is attracting attention as hydrogen carrier energy (for example, http://ieei.or.jp/2015/03/expl150317/). Since ammonia does not have carbon atoms, it is possible to avoid a situation where carbon dioxide (greenhouse gas) is discharged when used as fuel. Therefore, in the fertilizer manufacturing apparatus 100 of this embodiment, by using ammonia as a fuel, it is possible to generate electric power while reducing (or reducing to zero) carbon dioxide emission, and further manufacturing nitrogen fertilizer. Is possible.

  Moreover, since the fertilizer manufacturing apparatus 100 manufactures nitrogen fertilizer from fuel NOx, it can avoid the situation where fuel NOx is discharged | emitted outside as combustion exhaust gas. For this reason, it is possible to omit the denitration device as compared with a conventional system equipped with a denitration device that reduces NOx from the combustion exhaust gas.

(simulation)
Using general-purpose chemical reaction analysis software (CHEMKIN-II), the concentration of NO produced under the conditions shown in Comparative Examples 1 to 3 and Examples 1 to 4 below was calculated. FIG. 3 is a diagram for explaining simulation conditions and simulation results. The conditions (pressure, equivalent ratio, calculation region, etc.) other than the fuel and the oxidant were all the same in Comparative Examples 1 to 3 and Examples 1 to 4.

  In Comparative Example 1, the fuel was only methane (methane combustion only) and the oxidant was air. In Comparative Example 2, the fuel was only methane, and the oxidant was oxygen enriched gas of 40% oxygen and 60% nitrogen. In Comparative Example 3, the fuel was only methane and the oxidant was oxygen only (oxygen 100%).

  On the other hand, in Example 1, the fuel was only ammonia (ammonia only) and the oxidant was air. In Example 2, the fuel was a mixed fuel of 50% ammonia and 50% methane, and the oxidant was air. In Example 3, the fuel was only ammonia, and the oxidant was oxygen enriched gas of 40% oxygen and 60% nitrogen. In Example 4, the fuel was only ammonia and the oxidant was oxygen only (oxygen 100%).

  As a result, in Comparative Example 3, NO is not generated (NO concentration is zero). Moreover, when Example 1 was compared with Comparative Example 1, it was found that Example 1 produced 24.3 times as much NO as Comparative Example 1. Moreover, when Example 2 was compared with Comparative Example 1, it was confirmed that Example 2 produced 49.2 times as much NO as Comparative Example 1. Furthermore, when Example 3 was compared with Comparative Example 1, it was found that Example 3 produced 109 times as much NO as Comparative Example 1. Moreover, when Example 3 was compared with Comparative Example 2, it was confirmed that Example 3 produced 2.15 times as much NO as Comparative Example 2. Furthermore, when Example 4 was compared with Comparative Example 1, it was found that Example 4 produced 287 times more NO than Comparative Example 1.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to this embodiment. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Understood.

  For example, in the above-described embodiment, natural gas has been described as an example of the fuel supplied to the combustion unit 130. However, the fuel may be a substance that has higher combustibility than ammonia or a substance that promotes combustion of ammonia. The fuel is, for example, one or both of hydrocarbons (methane, ethane, propane, butane, biodiesel fuel, etc.), hydrogen, waste plastic fuel, and wood fuel (wood chips, wood pellets, etc.). .

  In the above-described embodiment, the combustion unit 130 has been described by taking an oxygen-enriched gas as an example of an oxidizing agent that burns ammonia. However, the oxidizing agent may be a gas containing at least oxygen, for example, air.

  Moreover, in the said embodiment, the structure which the fertilizer manufacturing apparatus 100 was equipped with the premixer 120 was mentioned as an example, and was demonstrated. However, the premixer 120 is not an essential configuration. For example, ammonia and fuel may be separately supplied to the combustion unit 130.

  Moreover, in the said embodiment, the structure which produces electric power with the combustion exhaust gas produced | generated in the combustion part 130 was mentioned as an example, and was demonstrated. However, the configuration of the combustion unit 130 is not limited as long as at least ammonia can be combusted to generate combustion exhaust gas. For example, the combustion unit may be constituted by an industrial combustion furnace.

In the above embodiment, the suction unit 220 has been described as an example the configuration to be used directly as a fertilizer what was adsorbed NO ₂ to the adsorbent. However, NO ₂ may be concentrated using a pressure swing adsorption method (PSA method), an alkali absorption method, or the like, or nitric acid may be produced. For example, zeolite is used as the adsorbent. Then, the combustion exhaust gas adsorption column containing a zeolite supply, in contact with the zeolite, to adsorb the NO ₂ in the zeolite. Thereafter, the adsorption tower is sucked with a vacuum pump to reduce the pressure, and NO ₂ is desorbed from the zeolite. The NO ₂ thus desorbed may be cooled, liquefied and concentrated. Moreover, an alkali absorbing liquid (amine absorbing liquid) is adopted as the adsorbent. Then, the combustion exhaust gas is supplied to the absorption tower which contains an alkaline absorbent solution, into contact with an alkaline absorption liquid, thereby absorbing the NO ₂ in an alkaline absorbing solution. Thereafter, the alkali absorbing liquid that has absorbed NO ₂ is supplied to the regeneration tower, and the alkali absorbing liquid is heated in the regeneration tower, whereby NO ₂ is vaporized from the alkali absorbing liquid. The NO ₂ thus vaporized may be cooled, liquefied and concentrated. Then, liquefied NO ₂ may be dissolved in water to form nitric acid (nitrogen fertilizer), and diluted and fertilized. Further, the liquefied NO ₂ may be processed into nitrate (for example, nitrogen fertilizer such as ammonium nitrate, sodium nitrate, calcium nitrate) and fertilized. Also, zeolite is adopted as the adsorbent. Then, the combustion exhaust gas adsorption column containing a zeolite supply, in contact with the zeolite, to adsorb the NO ₂ in the zeolite. Thereafter, water is supplied to the adsorption tower, the zeolite is washed, and NO ₂ is dissolved in water to produce nitric acid. The nitric acid (nitrogen fertilizer) produced in this way may be fertilized as it is, or the nitric acid may be processed into nitrate (for example, nitrogen fertilizer such as ammonium nitrate, sodium nitrate, calcium nitrate) and fertilized.

  INDUSTRIAL APPLICATION This invention can be utilized for the fertilizer manufacturing apparatus which manufactures the fertilizer comprised with a nitrogen compound, and the fertilizer manufacturing method.

100 Fertilizer manufacturing device 130 Combustion unit 200 Recovery unit

Claims (5)

A combustion section that burns at least ammonia to generate combustion exhaust gas;
A recovery unit for recovering nitrogen oxides from the combustion exhaust gas to produce nitrogen fertilizer;
A fertilizer manufacturing device comprising:   The fertilizer manufacturing apparatus according to claim 1, wherein the combustion unit co-fires the ammonia and fuel.   The fertilizer manufacturing apparatus according to claim 2, wherein the fuel is one or more of hydrocarbon, hydrogen, waste plastic fuel, and wood fuel.   The fertilizer manufacturing apparatus according to any one of claims 1 to 3, wherein the combustion unit burns the ammonia with a gas having a higher oxygen content than air. A process of burning at least ammonia to produce combustion exhaust gas;
Recovering nitrogen oxides from the combustion exhaust gas to produce nitrogen fertilizer;
Fertilizer manufacturing method including.

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