System for recovering reactive nitrogen in combustion process and power generation equipment

Abstract

To provide a system that effectively utilizes (reuses) reactive nitrogen by drastically reducing energy.SOLUTION: The system comprises combustion means 1 that involves the emission of NOX, oxidizing means 2 for oxidizing NOX emitted by the combustion means 1 to water-soluble N2O5, dissolution oxidization means 3 for dissolving oxidized N2O5 to NO3-, first converting means 4 for converting dissolved NO3- to nitrate and recovering the same, reduction means 5 for reducing dissolved NO3- to NH4+ and converting the reduced NH4+ to NH3 or ammonium salt and recovering the same, and NH3 converting means 6.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for producing insoluble NOx emissions from a combustion process, the method comprising the steps of: X The present invention relates to a recovery system for recovering the above-mentioned reactant nitrogen as valuable reactive nitrogen, and a power generation facility. [Background technology]

[0002] Nitrogen is essential for life, and is used, for example, as fertilizer in the form of reactive nitrogen such as ammonia (NH3). Its use as a fuel for combustion is also being considered. It is believed that the use of NH3 as a fuel for combustion can meet the demand for a decarbonized society. Most of the reactive nitrogen discharged after use (nitrogen-containing gas and nitrogen-containing wastewater) can be rendered harmless into N2 (nitrogen molecules) (for example, Patent Document 1).

[0003] To obtain NH3, N2 in the atmosphere is reacted with H2 (hydrogen molecules) produced from fossil fuels using external energy. Then, for example, NO contained in combustion exhaust gas is X is decomposed into N2 using external energy and NH3 as a reducing agent, making it harmless (denitrified).

[0004] Thus, reactive nitrogen such as NH3 is currently used in various fields. As the creation of a decarbonized society becomes increasingly important, it is expected that the demand for decarbonized fuels such as NH3 will increase significantly. In this situation, there has been a demand for technology that can effectively use reactive nitrogen with a significant reduction in the amount of energy used to detoxify it. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2017-189719 A Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention has been made in view of the above circumstances, and relates to a method for producing insoluble NOx, mainly containing NOx that is insoluble in water, emitted in a combustion process. X The objective of the present invention is to provide a reactive nitrogen recovery system for a combustion process, which can significantly reduce energy consumption and effectively utilize (reuse) the reactive nitrogen by recovering reactive nitrogen as reactive nitrogen.

[0007] The present invention has been made in view of the above circumstances, and provides a method for producing insoluble NOx, mainly containing NOx that is insoluble in water, emitted in a combustion process. X The present invention aims to provide a power generation facility equipped with an exhaust gas treatment means that can effectively utilize (reuse) reactive nitrogen while significantly reducing energy consumption by recovering reactive nitrogen as reactive nitrogen. [Means for solving the problem]

[0008] The present invention The reactive nitrogen recovery system for the combustion process is a system for recovering insoluble NO, which mainly contains NO, which is insoluble in water. X and (disposed in an exhaust system of the combustion means) absorbing insoluble NOx discharged by the combustion means, the insoluble NOx being mainly composed of NOx insoluble in water. X an oxidation means for oxidizing the water-soluble nitrogen oxides to water-soluble nitrogen oxides, and dissolving or dissolving and oxidizing the water-soluble nitrogen oxides oxidized by the oxidation means to produce NO3 - and a dissolving / oxidizing means for dissolving or oxidizing NO3 - and a first conversion means for converting the nitrate into a nitrate and recovering the nitrate. It is preferable that

[0009] This means: Insoluble NOx from exhaust gases from combustion means, mainly containing NOx that is insoluble in water X Nitrates can be obtained and recovered from the nitrates. Therefore, insoluble NO, which mainly contains NO, which is insoluble in water, can be recovered. XFor example, the ratio of two-stage combustion (two-stage combustion rate) can be increased or the air ratio can be decreased to reduce the amount of insoluble NO, which mainly contains NO that is insoluble in water. X Therefore, for example, when coal is used as fuel, combustion can be performed to reduce unburned carbon, and the quality of ash can be improved. X This makes it possible to emit noxious gases during combustion, which reduces restrictions on combustion and eliminates the need to add NH3 to the exhaust gas for denitrification, thereby preventing corrosion of pipes and other problems.

[0010] "Insoluble NO, which mainly contains NO that is insoluble in water X The "water" in "water-soluble nitrogen oxides" does not only mean "pure water" but also includes "aqueous solutions, slurries, etc."

[0011] Claim 1 to achieve the above object The reactive nitrogen recovery system in the combustion process of the present invention is a system for recovering insoluble NOx, which mainly contains NOx that is insoluble in water. X and a combustion means for emitting insoluble NOx, mainly including NOx that is insoluble in water, emitted by the combustion means. X an oxidation means for oxidizing the water-soluble nitrogen oxides to water-soluble nitrogen oxides, and dissolving or dissolving and oxidizing the water-soluble nitrogen oxides oxidized by the oxidation means to produce NO3 - and a dissolving / oxidizing means for dissolving or oxidizing NO3 - and a second conversion means for converting the above-mentioned into NH3 or an ammonium salt, or into NH3 and an ammonium salt, and recovering the same. , NH converted by the second conversion means 3 is used as fuel (in whole or in part) for the combustion means. It is characterized by:

[0012] Claim 1 In the present invention, the insoluble NOx in the exhaust gas from the combustion means mainly contains NOx that is insoluble in water. X From the reaction, NH3 or ammonium salts, or NH3 and ammonium salts, can be obtained and recovered. Therefore, insoluble NO, which mainly contains water-insoluble NO, can be recovered. XFor example, the ratio of two-stage combustion (two-stage combustion rate) can be increased or the air ratio can be decreased to reduce the amount of insoluble NO, which mainly contains NO that is insoluble in water. X Therefore, for example, when coal is used as fuel, combustion can be performed to reduce unburned carbon, and the quality of ash can be improved. X This makes it possible to emit noxious gases during combustion, which reduces restrictions on combustion and eliminates the need to add NH3 to the exhaust gas for denitrification, thereby preventing corrosion of pipes and other problems. And, insoluble NOx in the exhaust gas from the combustion means, which mainly contains NOx that is insoluble in water X NH obtained from 3 can be used as fuel (in whole or in part) for combustion means (nitrogen recycling). The insoluble NOx that flows out, mainly containing water-insoluble NOx, X This can almost completely eliminate the need for energy to render the waste harmless, and reduce the amount of energy required.

[0013] In addition, to achieve the above objectives Claim 2 The reactive nitrogen recovery system in the combustion process of the present invention is a system for recovering insoluble NOx, which mainly contains NOx that is insoluble in water. X and a combustion means for emitting insoluble NOx, mainly including NOx that is insoluble in water, emitted by the combustion means. X an oxidation means for oxidizing the water-soluble nitrogen oxides to water-soluble nitrogen oxides, and dissolving or dissolving and oxidizing the water-soluble nitrogen oxides oxidized by the oxidation means to produce NO3 - and a dissolving / oxidizing means for dissolving or oxidizing NO3 - a first conversion means for converting NO3 into nitrate and recovering it; and a second conversion means for recovering NO3 dissolved or dissolved and oxidized by the dissolution and oxidation means. - and a second conversion means for converting the above-mentioned into NH3 or an ammonium salt, or into NH3 and an ammonium salt, and recovering the same. , NH converted by the second conversion means 3 is used as fuel (in whole or in part) for the combustion means. It is characterized by:

[0014] Claim 2 In the present invention, the insoluble NOx in the exhaust gas from the combustion means mainly contains NOx that is insoluble in water. XNitrates, NH3 or ammonium salts, or NH3 and ammonium salts, can be obtained and recovered from the reaction. Therefore, the insoluble NOx, which mainly contains NOx, which is insoluble in water, can be recovered. X For example, the ratio of two-stage combustion (two-stage combustion rate) can be increased or the air ratio can be decreased to reduce the amount of insoluble NO, which mainly contains NO that is insoluble in water. X Therefore, for example, when coal is used as fuel, combustion can be performed to reduce unburned carbon, and the quality of ash can be improved. X This makes it possible to emit noxious gases during combustion, which reduces restrictions on combustion and eliminates the need to add NH3 to the exhaust gas for denitrification, thereby preventing corrosion of pipes and other problems. And, insoluble NOx in the exhaust gas from the combustion means, which mainly contains NOx that is insoluble in water X NH obtained from 3 can be used as fuel (in whole or in part) for combustion means (nitrogen recycling). The insoluble NOx that flows out, mainly containing water-insoluble NOx, X This can almost completely eliminate the need for energy to render the waste harmless, and reduce the amount of energy required.

[0015] still, The present invention described above (claims 1 and 2) Insoluble NO, mainly containing NO which is insoluble in water, in a reactive nitrogen recovery system for a combustion process described in X is a substance that is composed mainly of NO and does not contain other NO X It is considered to be a whole substance containing trace amounts of ingredients.

[0016] The water soluble nitrogen oxides of the combustion process reactive nitrogen recovery system preferably comprise at least one of NO2, N2O3, N2O4, N2O5, and the oxidation means preferably comprises means for injecting ozone.

[0017] Therefore, in the combustion process reactive nitrogen recovery system of the present invention, insoluble NOx, mainly containing NOx that is insoluble in water, emitted in the combustion process is recovered. X By recovering this as reactive nitrogen, it is possible to significantly reduce energy consumption and effectively utilize (reuse) the reactive nitrogen.

[0018] Also , claim 3 The reactive nitrogen recovery system of the present invention in a combustion process comprises: Claim 1 or Claim 2 In the system for recovering reactive nitrogen in a combustion process described in the above, the second conversion means is a nitrogen gas that is dissolved or dissolved and oxidized by the dissolution and oxidation means. - Reduce to NH4 + At the same time, reduced NH4 + is converted to NH3 or an ammonium salt, or to NH3 and an ammonium salt, and recovered.

[0019] Claim 3 In the present invention, dissolved or dissolved and oxidized NO3 - is reduced to NH4 + and reduced NH4 + is converted to NH3 or an ammonium salt, or to NH3 and an ammonium salt.

[0020] Also, Claim 4 The reactive nitrogen recovery system of the present invention in a combustion process comprises: Claim 1 or Claim 2 In the system for recovering reactive nitrogen in a combustion process described in the above, the combustion means is characterized in that a high-pressure fluid is obtained by combusting a fuel.

[0021] Claim 4 In the present invention, a boiler for obtaining steam for driving a steam turbine and a combustor for obtaining combustion gas for driving a gas turbine can be applied as the combustion means.

[0022] Also, Claim 5 The reactive nitrogen recovery system of the present invention in a combustion process comprises: Claim 1 or Claim 2 In the system for recovering reactive nitrogen in a combustion process described in the above, the combustion means is an engine that obtains power by burning fuel.

[0023] Claim 5In the present invention, an internal combustion engine having a combustion chamber (such as a diesel engine for a large vehicle or ship) can be used as the combustion means.

[0024] The present invention The power generation facility mainly uses insoluble NO, which is insoluble in water. X The present invention is provided with a combustion means that accompanies the emission of NO, an expansion turbine that expands a high-pressure fluid obtained by the combustion in the combustion means to obtain power for generating electricity, and an exhaust gas treatment means that treats the exhaust gas after the power for generating electricity has been obtained, and the exhaust gas treatment means is configured to treat insoluble NO in the exhaust gas, which mainly contains NO that is insoluble in water. X an oxidation means for oxidizing the water-soluble nitrogen oxides to water-soluble nitrogen oxides, and dissolving or dissolving and oxidizing the water-soluble nitrogen oxides oxidized by the oxidation means to produce NO3 - and a dissolving / oxidizing means for dissolving or oxidizing NO3 - a first converting means for converting the nitrate to a nitrate and recovering the nitrate. is preferred.

[0025] This means: Insoluble NOx, which mainly contains NOx that is insoluble in water, is found in exhaust gases (boiler exhaust gases, gas turbine exhaust gases) after generating power. X Nitrates can be obtained and recovered from the nitrates. Therefore, insoluble NO, which mainly contains NO, which is insoluble in water, can be recovered. X For example, the ratio of two-stage combustion can be increased or the air ratio can be decreased to reduce the amount of insoluble NOx, which mainly contains NOx that is insoluble in water. X Therefore, for example, when coal is used as fuel, combustion can be performed to reduce unburned carbon, and the quality of ash can be improved. X This makes it possible to emit noxious gases during combustion, which reduces restrictions on combustion and eliminates the need to add NH3 to the exhaust gas for denitrification, thereby preventing corrosion of pipes and other problems.

[0026] above To achieve the above objectives Claim 6The power generation equipment of the present invention is characterized in that it generates insoluble NOx mainly containing NOx that is insoluble in water. X The present invention is provided with a combustion means that accompanies the emission of NO, an expansion turbine that expands a high-pressure fluid obtained by the combustion in the combustion means to obtain power for generating electricity, and an exhaust gas treatment means that treats the exhaust gas after the power for generating electricity has been obtained, and the exhaust gas treatment means is configured to treat insoluble NO in the exhaust gas, which mainly contains NO that is insoluble in water. X an oxidation means for oxidizing the water-soluble nitrogen oxides to water-soluble nitrogen oxides, and dissolving or dissolving and oxidizing the water-soluble nitrogen oxides oxidized by the oxidation means to produce NO3 - and a dissolving / oxidizing means for dissolving or oxidizing NO3 - and a second conversion means for converting the NH3 or ammonium salt, or NH3 and ammonium salt, and recovering the NH3 or ammonium salt. The combustion means is configured to use NH 3 The combustion means is provided with NH recovered in the second conversion means. 3 is provided It is characterized by:

[0027] Claim 6 In the present invention, the insoluble NOx, which mainly contains NOx insoluble in water, is extracted from exhaust gas (boiler exhaust gas, gas turbine exhaust gas) after generating power. X From the reaction, NH3 or ammonium salts, or NH3 and ammonium salts, can be obtained and recovered. Therefore, insoluble NO, which mainly contains water-insoluble NO, can be recovered. X For example, the ratio of two-stage combustion (two-stage combustion rate) can be increased or the air ratio can be decreased to reduce the amount of insoluble NO, which mainly contains NO that is insoluble in water. X Therefore, for example, when coal is used as fuel, combustion can be performed to reduce unburned carbon, and the quality of ash can be improved. X This makes it possible to emit noxious gases during combustion, which reduces restrictions on combustion and eliminates the need to add NH3 to the exhaust gas for denitrification, thereby preventing corrosion of pipes and other problems. And the insoluble NO in the exhaust gas of the expansion turbine, which mainly contains NO that is insoluble in water, X NH obtained from 3 can be used as fuel (in whole or in part) for combustion means (nitrogen recycling). The insoluble NOx that flows out, mainly containing water-insoluble NOx, X This can almost completely eliminate the need for energy to render the waste harmless, and reduce the amount of energy required.

[0028] In addition, to achieve the above objectives Claim 7 The power generation equipment of the present invention is characterized in that it generates insoluble NOx mainly containing NOx that is insoluble in water. X The present invention is provided with a combustion means that accompanies the emission of NO, an expansion turbine that expands a high-pressure fluid obtained by the combustion in the combustion means to obtain power for generating electricity, and an exhaust gas treatment means that treats the exhaust gas after the power for generating electricity has been obtained, and the exhaust gas treatment means is configured to treat insoluble NO in the exhaust gas, which mainly contains NO that is insoluble in water. X an oxidation means for oxidizing the water-soluble nitrogen oxides to water-soluble nitrogen oxides, and dissolving or dissolving and oxidizing the water-soluble nitrogen oxides oxidized by the oxidation means to produce NO3 - and a dissolving / oxidizing means for dissolving or oxidizing NO3 - a first conversion means for converting NO3 into nitrate and recovering the nitrate; and a second conversion means for recovering the NO3 dissolved or dissolved and oxidized by the dissolution and oxidation means. - and a second conversion means for converting the NH3 or ammonium salt, or NH3 and ammonium salt, and recovering the NH3 or ammonium salt. The combustion means is configured to use NH 3 The combustion means is provided with NH recovered in the second conversion means. 3 is provided It is characterized by:

[0029] Claim 7 In the present invention, the insoluble NOx, which mainly contains NOx insoluble in water, is extracted from exhaust gas (boiler exhaust gas, gas turbine exhaust gas) after generating power. X Nitrates, NH3 or ammonium salts, or NH3 and ammonium salts, can be obtained and recovered from the reaction. Therefore, the insoluble NOx, which mainly contains NOx, which is insoluble in water, can be recovered. X For example, the ratio of two-stage combustion (two-stage combustion rate) can be increased or the air ratio can be decreased to reduce the amount of insoluble NO, which mainly contains NO that is insoluble in water. X Therefore, for example, when coal is used as fuel, combustion can be performed to reduce unburned carbon, and the quality of ash can be improved. XThis makes it possible to emit noxious gases during combustion, which reduces restrictions on combustion and eliminates the need to add NH3 to the exhaust gas for denitrification, thereby preventing corrosion of pipes and other problems. And the insoluble NO in the exhaust gas of the expansion turbine, which mainly contains NO that is insoluble in water, X NH obtained from 3 can be used as fuel (in whole or in part) for combustion means (nitrogen recycling). The insoluble NOx that flows out, mainly containing water-insoluble NOx, X This can almost completely eliminate the need for energy to render the waste harmless, and reduce the amount of energy required.

[0030] still, The present invention described above (claims 6 and 7) Insoluble NO, mainly containing water-insoluble NO, in the power generation equipment described in X is a substance that is composed mainly of NO and does not contain other NO X It is considered to be a whole substance containing trace amounts of ingredients.

[0031] The water-soluble nitrogen oxides in the power plant preferably include at least one of NO2, N2O3, N2O4, and N2O5, and the oxidation means preferably includes means for injecting ozone.

[0032] Therefore, in the power generation system of the present invention, insoluble NOx, which mainly contains NOx that is insoluble in water, is emitted in the combustion process. X By recovering the reactive nitrogen, it is possible to provide a power generation facility equipped with an exhaust gas treatment means that can effectively utilize (reuse) the reactive nitrogen while significantly reducing energy consumption.

[0033] and, Claim 8 The power generation facility of the present invention relates to Claim 6 or claim 7 In the power generation facility described above, the second conversion means converts the NO3 dissolved or dissolved and oxidized by the dissolution / oxidation means into NO3 - Reduce to NH4 + At the same time, reduced NH4 + is converted to NH3 or an ammonium salt, or to NH3 and an ammonium salt, and recovered.

[0034] Claim 8 In the present invention, dissolved or dissolved and oxidized NO3 - is reduced to NH4 +and reduced NH4 + is converted to NH3 or an ammonium salt, or to NH3 and an ammonium salt. Effect of the Invention

[0035] The reactive nitrogen recovery system for a combustion process of the present invention is a system for recovering insoluble NOx emitted in a combustion process, which mainly comprises NOx that is insoluble in water. X By recovering this as reactive nitrogen, it is possible to significantly reduce energy consumption and effectively utilize (reuse) the reactive nitrogen.

[0036] In addition, the power generation equipment of the present invention can extract insoluble NOx, which is mainly composed of NOx that is insoluble in water, emitted in the combustion process. X By recovering the reactive nitrogen, it is possible to provide a power generation facility equipped with an exhaust gas treatment means that can effectively utilize (reuse) the reactive nitrogen while significantly reducing energy consumption. [Brief description of the drawings]

[0037] [Figure 1] FIG. 1 is a block diagram of a system for recovering reactive nitrogen in a combustion process according to one embodiment of the present invention. [Diagram 2] 1 is a schematic system diagram of a power generation facility according to an embodiment of the present invention. [Diagram 3] 4 is a graph showing the relationship between the two-stage combustion ratio and the NOX concentration and the proportion of unburned carbon. [Figure 4] FIG. 4 is a schematic system diagram of a power generation facility according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0038] FIG. 1 shows a block diagram for explaining an outline of the entire system for recovering reactive nitrogen in a combustion process according to one embodiment of the present invention.

[0039] As shown in the figure, the reactive nitrogen recovery system in the combustion process of the present invention recovers insoluble NO, which mainly contains NO that is insoluble in water.X The combustion means 1 is equipped with a combustion unit that emits nitrogen. The combustion unit 1 uses a fuel containing nitrogen, such as coal or NH3, and produces insoluble NOx, which mainly contains NOx that is insoluble in water. X (Mainly fuel NO. X Even if fuels that do not contain nitrogen, such as natural gas or hydrogen, are used, the N2 contained in the combustion air produces insoluble NOx, which mainly contains NOx that is insoluble in water. X (Thermal No. X ) is emitted.

[0040] Insoluble NOx in the exhaust gas from the combustion means 1, mainly containing NOx that is insoluble in water X (NO emitted from combustion means X ) is oxidized by the oxidation means 2 to water-soluble nitrogen oxides (containing at least one of NO2, N2O3, N2O4, and N2O5: for example, nitrogen oxides containing mainly N2O5: N2O5).

[0041] As the oxidation means 2, a means configured to be in a state where oxygen is supplied is applied. It is also possible to apply a means for injecting ozone. Furthermore, as the oxidation means, it is also possible to omit the combustion means 1 and the oxidation means 2 and use a "combustion device" that generates water-soluble nitrogen oxides (containing at least one of NO2, N2O3, N2O4, and N2O5: for example, nitrogen oxides mainly containing N2O5: N2O5) as the combustion means. In this case, the "combustion device" as the oxidation means corresponds to the "combustion means" and "oxidation means" recited in claim 1.

[0042] Insoluble NO, mainly consisting of NO that is insoluble in water X is converted into water-soluble nitrogen oxides mainly containing N2O5 by the oxidation means 2. In the following, N2O5 will be used as a representative example. When N2O5 is used, it is preferable to use a means for injecting ozone as the oxidation means 2.

[0043] The oxidized N2O5 is dissolved in the dissolution and oxidation means 3 to produce NO3 - In other words, when N2O5 is applied, N2O5 does not need to be oxidized to become NO3 -Therefore, the dissolution / oxidation means 3 is a means for only dissolving N2O5. - is converted to nitrates (for example, by crystallization) by the first conversion means 4 and recovered. The recovered nitrates are used as agricultural fertilizers (insoluble NOx mainly containing water-insoluble NOx). X Reuse of nitrogen in the soil: the nitrogen cycle).

[0044] In addition, when NO2, N2O3, and N2O4 are used as the water-soluble nitrogen oxides, in the dissolving / oxidizing means 3, NO2, N2O3, and N2O4 are dissolved and oxidized to NO3 - That is, the dissolving / oxidizing means 3 dissolves or dissolves and oxidizes the water-soluble nitrogen oxides to NO3 - It has become a means to

[0045] In addition, the oxidation means 2 and the dissolution / oxidation means 3 are omitted, and a "dissolution / oxidation device" is separately provided, and NO X converts NO2, N2O3, and N2O4 to NO3 - In this case, the "dissolving / oxidizing device" corresponds to the "oxidizing means" and "dissolving / oxidizing means" recited in claim 1.

[0046] On the other hand, NO3 dissolved in the dissolution / oxidation means 3 - is reduced by a reduction means 5 (second conversion means) that performs reduction by, for example, a biological reaction, an electrode reaction, a chemical reaction, or the like, to NH + Then, the reduced NH4 + is converted to NH3 by, for example, stripping conversion means (second conversion means) 6 and recovered. The recovered NH3 is used as fuel for the combustion means 1 (fuel for other combustion means), a reducing agent for external flue gas treatment (for denitrification), etc. (insoluble NO mainly containing NO that is insoluble in water X Reuse of nitrogen in the soil: the nitrogen cycle).

[0047] In addition, in the conversion means 6, NH4 +can also be converted to ammonium salts. can also be converted to NH3 and ammonium salts.

[0048] By using the recovered NH3 as fuel for the combustion means 1, the insoluble NO that mainly contains NO that is insoluble in water that flows out can be reduced. X This will almost completely eliminate the need for wastewater treatment, reduce the energy required to detoxify the wastewater, and achieve the recycling of nitrogen.

[0049] In the reactive nitrogen recovery system in the combustion process having the above configuration, insoluble NOx mainly containing NOx insoluble in water is recovered from the exhaust gas of the combustion means 1. X Nitrates and NH3 (ammonium salts) can be obtained and recovered from the insoluble NOx, which mainly contains NO that is insoluble in water. X Reuse of nitrogen in the combustion process (nitrogen cycle). Insoluble NOx, mainly consisting of water-insoluble NOx, is released during the combustion process. X By recovering reactive nitrogen, it is possible to effectively utilize (reuse) the reactive nitrogen without using energy to convert it to harmless N2, thereby enabling the recycling of reactive nitrogen with a significant reduction in energy consumption.

[0050] The reactive nitrogen recovery system in the combustion process of the present invention omits the reduction means 5 and conversion means 6, and dissolves or dissolves and oxidizes NO3 - It is also possible to omit the first conversion means 4 and recover the NO3 dissolved or dissolved and oxidized by the dissolution / oxidation means 3. - It is also possible to use a configuration in which the above is simply converted to NH3 (ammonium salt) by the reduction means 5 and the conversion means 6, and then recovered.

[0051] In addition, the NO3 dissolved or dissolved and oxidized by the dissolution / oxidation means 3 - NH4 + and the reduced NH4 + is converted to NH3 and recovered, but NO3 - If the structure is such that it converts to NH3 (ammonium salt), the reduced NH4+ is not limited to a configuration in which

[0052] The above-mentioned combustion process corresponds to, for example, a process from a fuel supply system to an exhaust system in a boiler or combustor of a power generation facility (power generating equipment) and a process from a fuel supply system to an exhaust system in a diesel engine of a large vehicle or ship. By applying the reactive nitrogen recovery system in the combustion process of the present invention, it is possible to recover insoluble NOx, which mainly contains NOx that is insoluble in water, in a power generation facility or a diesel engine. X This makes it possible to burn fuel that emits CO2.

[0053] An example of a power generation facility to which a system for recovering reactive nitrogen in a combustion process is applied will be described with reference to Figs.

[0054] Figure 2 shows a schematic diagram of the overall system of a power generation facility that uses the reactive nitrogen recovery system in the combustion process described above, and Figure 3 shows the two-stage combustion ratio and the ratio of insoluble NO, which mainly contains NO that is insoluble in water. X The relationship between the concentration and the unburned carbon fraction is shown.

[0055] As shown in Fig. 2, power generation facility (thermal power generation facility) 11 includes a boiler 12 that uses coal as fuel mainly to obtain high-pressure steam, which is a high-temperature, high-pressure fluid, and the high-pressure steam generated in the boiler 12 is expanded and driven by a steam turbine 13, which is an expansion turbine, and power is generated by driving the steam turbine 13. Also, an exhaust gas treatment means 14 is provided that treats exhaust gas from the boiler 12 (exhaust gas after obtaining power for generating electricity).

[0056] The exhaust gas treatment means 14 is equipped with the system shown in Fig. 1. That is, insoluble NO in exhaust gas, which mainly contains NO that is insoluble in water, is X The oxidation means 2 is provided for oxidizing the nitrogen oxides (containing at least one of NO2, N2O3, N2O4, and N2O5: for example, nitrogen oxides containing mainly N2O5: N2O5) into water-soluble nitrogen oxides. The N2O5 oxidized by the oxidation means 2 is dissolved to produce NO3 -The dissolving / oxidizing means 3 is provided to convert the NO3 - to nitrates and recovering the nitrates, for example as a fertilizer.

[0057] In addition, when the nitrogen oxide oxidized by the oxidation means 2 is N2O5, the dissolving / oxidizing means 3 only dissolves N2O5. When the nitrogen oxide oxidized by the oxidation means 2 is something other than N2O5 (such as NO2), the dissolving / oxidizing means 3 dissolves and oxidizes the nitrogen oxide, and the nitrogen oxide is dissolved and oxidized by the dissolving / oxidizing means 3 to become NO3 - It is said.

[0058] Then, the NO3 dissolved in the dissolution / oxidation means 3 - Reduce to NH4 + (reduction means 5), and the reduced NH4 + The apparatus is provided with a conversion means 6 that converts the ammonium salt into NH3 (ammonium salt) and recovers it. When the ammonium salt is recovered by the conversion means 6, the recovered ammonium salt is recovered as, for example, a fertilizer.

[0059] The boiler 12 is supplied with NH3 recovered in the conversion means 6 as part of the fuel. When the fuel contains sulfur, SO2 in the exhaust gas is simultaneously absorbed in the dissolution and oxidation means 3. The exhaust gas treatment means 14 is appropriately equipped with a device for removing soot and a device for removing impurities.

[0060] By providing the exhaust gas treatment means 14, insoluble NOx, which mainly contains NOx that is insoluble in water, can be removed. X (Mainly fuel NO. X In other words, when the two-stage combustion ratio is increased, the amount of insoluble NOx, which mainly contains NOx that is insoluble in water, increases as shown by the solid line in FIG. X As the concentration of NOx decreases, the proportion of unburned carbon increases, as shown by the dotted line in Figure 3. Conversely, as the two-stage combustion ratio decreases, the proportion of insoluble NOx, which mainly contains NOx that is insoluble in water, increases, as shown by the solid line in Figure 3. XWhile the concentration increases, the proportion of unburned carbon decreases, as shown by the dotted line in Figure 3.

[0061] By providing the exhaust gas treatment means 14 (using the system shown in FIG. 1), the two-stage combustion rate can be increased and the air ratio can be reduced to reduce insoluble NOx, which mainly contains NOx that is insoluble in water. X (Mainly fuel NO. X ), and the insoluble NO, which mainly contains NO that is insoluble in water, is not required to be reduced. X (Mainly fuel NO. X This allows combustion that emits less carbon dioxide, which reduces restrictions on combustion. It also allows combustion that reduces unburned carbon, improves the quality of the ash, and promotes the use of ash.

[0062] Furthermore, since there is no need to inject NH3 into the exhaust gas for denitrification, it is possible to suppress the occurrence of corrosion of pipes, etc. Since NH3 is not injected into the exhaust gas, NH3 does not adhere to dust collected in the dust removal device.

[0063] Another embodiment of a power generation facility to which a system for recovering reactive nitrogen in a combustion process is applied will be described with reference to FIG.

[0064] FIG. 4 shows a schematic diagram of the entire power generation facility to which the reactive nitrogen recovery system in the combustion process described above is applied.

[0065] As shown in Fig. 4, a power generation facility (thermal power generation facility) 21 is provided with a combustor 22 that obtains combustion gas using natural gas as fuel, and compressed air is supplied to the combustor 22 from a compressor 23. The high-temperature, high-pressure combustion gas (high-pressure fluid) from the combustor 22 is expanded and driven by an expansion turbine 24, and power is generated by driving the expansion turbine 24. An exhaust gas treatment means 25 is provided to treat exhaust gas that has completed its work in the expansion turbine 24 (exhaust gas after generating power).

[0066] The exhaust gas treatment means 25 is equipped with the system shown in Fig. 1, similar to the power generation facility shown in Fig. 2. That is, insoluble NOx in the exhaust gas, which mainly contains NOx that is insoluble in water, is treated. X (NO derived from N2 contained in the combustion air X : Thermal No. X The oxidation means 2 is provided for oxidizing the nitrogen oxides (NO2, N2O3, N2O4, and N2O5) into water-soluble nitrogen oxides (containing at least one of NO2, N2O3, N2O4, and N2O5: for example, nitrogen oxides containing mainly N2O5: N2O5). The N2O5 oxidized by the oxidation means 2 is dissolved to produce NO3 - The dissolving / oxidizing means 3 is provided to convert the NO3 - A first conversion means 4 is provided for converting the above-mentioned to nitrates and recovering the nitrates.

[0067] In addition, when the nitrogen oxide oxidized by the oxidation means 2 is N2O5, the dissolving / oxidizing means 3 only dissolves N2O5. When the nitrogen oxide oxidized by the oxidation means 2 is something other than N2O5 (such as NO2), the dissolving / oxidizing means 3 dissolves and oxidizes the nitrogen oxide, and the nitrogen oxide is dissolved and oxidized by the dissolving / oxidizing means 3 to become NO3 - It is said.

[0068] Then, the NO3 dissolved in the dissolution / oxidation means 3 - Reduce to NH4 + (reduction means 5), and the reduced NH4 + The apparatus is provided with a conversion means 6 that converts the ammonium salt into NH3 (ammonium salt) and recovers it. When the ammonium salt is recovered by the conversion means 6, the recovered ammonium salt is recovered as, for example, a fertilizer.

[0069] NH3 recovered by the conversion means 6 is supplied as part of the fuel to the combustor 22. When the fuel contains sulfur, the dissolution and oxidation means 3 simultaneously absorbs SO2 in the exhaust gas.

[0070] By providing the exhaust gas treatment means 25 (using the system shown in FIG. 1), insoluble NO mainly containing NO that is insoluble in water can be removed. X (Mainly thermal NOX ), and the insoluble NO, which mainly contains NO that is insoluble in water, is not required to be reduced. X (Mainly thermal NO X ) combustion is possible, which reduces restrictions on combustion.

[0071] The reactive nitrogen recovery system in the combustion process of the present invention can be provided in the exhaust systems of diesel engines of large vehicles, ships, etc., in addition to power generating systems. [Industrial Applicability]

[0072] The present invention relates to a method for producing insoluble NOx emissions from a combustion process, the method comprising the steps of: X The present invention can be used in industrial fields such as recovery systems for recovering valuable reactive nitrogen, and power generation facilities. [Explanation of symbols]

[0073] 1. Combustion Method 2. Oxidation Method 3. Dissolution and oxidation methods 4. First conversion method 5. Rebate methods 6. Conversion methods 11, 21 Power generation facilities 12. Boiler 13. Steam Turbine 14, 25 Exhaust gas treatment means 22 Combustor 23 Compressor 24 Expansion turbine

Claims

1. Insoluble NO, mainly consisting of water-insoluble NO Ｘ A combustion means with emission of Insoluble NOx discharged by the combustion means, mainly containing NOx insoluble in water Ｘ to water-soluble nitrogen oxides; The water-soluble nitrogen oxides oxidized by the oxidation means are dissolved or dissolved and oxidized to produce NO ３ － a dissolving / oxidizing means for NO dissolved or dissolved and oxidized by the dissolving / oxidizing means ３ － and a first conversion means for converting the nitrate into a nitrate and recovering the nitrate.

1. A system for recovering reactive nitrogen in a combustion process, comprising:

2. Insoluble NO, mainly consisting of water-insoluble NO Ｘ A combustion means with emission of Insoluble NOx discharged by the combustion means, mainly containing NOx insoluble in water Ｘ to water-soluble nitrogen oxides; The water-soluble nitrogen oxides oxidized by the oxidation means are dissolved or dissolved and oxidized to produce NO ３ － a dissolving / oxidizing means for NO dissolved or dissolved and oxidized by the dissolving / oxidizing means ３ － NH ３ Or ammonium salt, or NH ３ and a second conversion means for converting the ammonium salt into an ammonium salt and recovering the ammonium salt.

1. A system for recovering reactive nitrogen in a combustion process, comprising:

3. Insoluble NO, mainly consisting of water-insoluble NO Ｘ A combustion means with emission of Insoluble NOx discharged by the combustion means, mainly containing NOx insoluble in water Ｘ to water-soluble nitrogen oxides; The water-soluble nitrogen oxides oxidized by the oxidation means are dissolved or dissolved and oxidized to produce NO ３ － a dissolving / oxidizing means for NO dissolved or dissolved and oxidized by the dissolving / oxidizing means ３ － a first conversion means for converting the above into a nitrate and recovering the same; NO dissolved or dissolved and oxidized by the dissolving / oxidizing means ３ － NH ３ Or ammonium salt, or NH ３ and a second conversion means for converting the ammonium salt into an ammonium salt and recovering the ammonium salt.

1. A system for recovering reactive nitrogen in a combustion process, comprising:

4. 4. The system for recovering reactive nitrogen in a combustion process according to claim 2 or 3, The second conversion means is NO dissolved or dissolved and oxidized by the dissolving / oxidizing means ３ － is reduced to NH ４ ＋ At the same time, reduced NH ４ ＋ NH ３ Or ammonium salt, or NH ３ and converting it into an ammonium salt to recover it.

1. A system for recovering reactive nitrogen in a combustion process, comprising:

5. 4. The system for recovering reactive nitrogen in a combustion process according to claim 2 or 3, NH converted by the second conversion means ３ is used as fuel for the combustion means.

1. A system for recovering reactive nitrogen in a combustion process, comprising:

6. A system for recovering reactive nitrogen in a combustion process according to any one of claims 1 to 3, The combustion means obtains a high-pressure fluid by burning fuel.

1. A system for recovering reactive nitrogen in a combustion process, comprising:

7. A system for recovering reactive nitrogen in a combustion process according to any one of claims 1 to 3, The combustion means is an engine that obtains power by burning fuel.

1. A system for recovering reactive nitrogen in a combustion process, comprising:

8. Insoluble NO, mainly consisting of water-insoluble NO Ｘ A combustion means with emission of an expansion turbine for expanding the high-pressure fluid obtained by the combustion in the combustion means to generate electric power; and an exhaust gas treatment means for treating exhaust gas after generating power, The exhaust gas treatment means includes: Insoluble NO in exhaust gas, mainly consisting of NO that is insoluble in water Ｘ to water-soluble nitrogen oxides; The water-soluble nitrogen oxides oxidized by the oxidation means are dissolved or dissolved and oxidized to produce NO ３ － a dissolving / oxidizing means for NO dissolved or dissolved and oxidized by the dissolving / oxidizing means ３ － a first converting means for converting the above-mentioned to a nitrate and recovering the nitrate. The power generation facility is characterized by:

9. Insoluble NO, mainly consisting of water-insoluble NO Ｘ A combustion means with emission of an expansion turbine for expanding the high-pressure fluid obtained by the combustion in the combustion means to generate electric power; and an exhaust gas treatment means for treating exhaust gas after generating power, The exhaust gas treatment means includes: Insoluble NO in exhaust gas, mainly consisting of NO that is insoluble in water Ｘ to water-soluble nitrogen oxides; The water-soluble nitrogen oxides oxidized by the oxidation means are dissolved or dissolved and oxidized to produce NO ３ － a dissolving / oxidizing means for NO dissolved or dissolved and oxidized by the dissolving / oxidizing means ３ － NH ３ Or ammonium salt, or NH ３ and a second conversion means for converting the ammonium salt into an ammonium salt and recovering the ammonium salt. The power generation facility is characterized by:

10. Insoluble NO, mainly consisting of water-insoluble NO Ｘ A combustion means with emission of an expansion turbine for expanding the high-pressure fluid obtained by the combustion in the combustion means to generate electric power; and an exhaust gas treatment means for treating exhaust gas after generating power, The exhaust gas treatment means includes: Insoluble NO in exhaust gas, mainly consisting of NO that is insoluble in water Ｘ to water-soluble nitrogen oxides; The water-soluble nitrogen oxides oxidized by the oxidation means are dissolved or dissolved and oxidized to produce NO ３ － a dissolving / oxidizing means for NO dissolved or dissolved and oxidized by the dissolving / oxidizing means ３ － a first converting means for converting the ammonia to a nitrate and recovering the nitrate; NO dissolved or dissolved and oxidized by the dissolving / oxidizing means ３ － NH ３ Or ammonium salt, or NH ３ and a second conversion means for converting the ammonium salt into an ammonium salt and recovering the ammonium salt. The power generation facility is characterized by:

11. The power generation facility according to claim 9 or 10, The second conversion means is NO dissolved or dissolved and oxidized by the dissolving / oxidizing means ３ － is reduced to NH ４ ＋ At the same time, reduced NH ４ ＋ NH ３ Or ammonium salt, or NH ３ and converting it into an ammonium salt to recover it. The power generation facility is characterized by:

12. The power generation facility according to claim 9 or 10, The combustion means is Part or all of the fuel is NH ３ It is said that, The combustion means includes: NH recovered by the second conversion means ３ is provided The power generation facility is characterized by:

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