Catalysts for ammonia production, ammonia production methods and apparatus, and denitrification methods and apparatus.

Abstract

To provide a catalyst that enables the production of ammonia from exhaust in high yield, an ammonia production method and an ammonia production device, and a denitration method and a denitration device.SOLUTION: The present invention relates to a catalyst for the production of ammonia, which produces NH3 from NOX and a reductant in the presence of oxygen, the catalyst comprising a carrier composed of TiO2, with a metal supported thereon. The present invention also relates to an ammonia production method that uses the catalyst for the production of ammonia, disclosed herein, to produce NH3 from NOX and a reductant with one pot in the presence of oxygen without concentrating NOX.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a catalyst for ammonia production, an ammonia production method, a production apparatus, a denitration method, and a denitration apparatus.

Background Art

[0002] In the selective catalytic reduction denitration of nitrogen oxides (NO , 1-x , , x ) using ammonia (NH3) (hereinafter referred to as NH3-SCR denitration), labor saving and cost reduction in the whole process including the production, transportation, storage, and injection of NH3 as a reducing agent are required.

[0003] The NH3-SCR denitration process has already been applied to various exhaust gas treatments, but in all cases, storage and injection equipment for NH3 as a reducing agent is required, and furthermore, it is necessary to produce NH3 and transport it to the denitration equipment site. In particular, the NH3 production process requires high temperature and high pressure, and furthermore, requires high-purity raw materials N2 and H2, and a great deal of energy is required to produce these high-purity raw materials.

[0004] The following Non-Patent Document 1 describes a method for purifying NOx during lean combustion by a mechanism in which NOx is oxidized and stored as a nitrate, and the NOx stored during fuel-rich combustion is reductively purified by reaction with HC or CO. In addition, a technique for suppressing the combustion loss to 1% or less by adding an alkaline substance as a NOx storage material to a conventional three-way catalyst is described.

[0005] Non-Patent Document 2 describes a technique using an H-type mordenite zeolite adsorbent to improve the NOx purification rate under high-temperature transient conditions with respect to the NH3-SCR denitration process. [[ID=​​​​​​​

Prior Art Documents

Non-Patent Documents

[0007]

Non-Patent Document 1

Non-Patent Document 2

Non-Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0008] Conventionally, for the denitrification process of automotive exhaust gases, three-way catalysts and NO X storage reduction (NSR) catalysts have been commercially used. However, all of the conventional catalysts have poor reactivity in a state where oxygen always coexists, such as in power plants, waste treatment facilities, and factory exhaust gases, and NO XIt is necessary to first absorb and concentrate the nitrogen, and then neutralize it to N2 under oxygen-free conditions equivalent to automobile exhaust gas during high-concentration fuel combustion (rich phase). Also, NO X In selective catalytic reduction denitrification (SCR), processes centered around Ag / Al2O3 catalysts using ethanol as a reducing agent (EtOH-SCR) are being pursued. However, this process produces approximately 30% NH3 as a by-product. With this catalyst, the by-product NH3 does not act as a reducing agent, and the leakage of NH3 is a problem for denitrification. On the other hand, when viewed as an NH3 manufacturing process, there is a problem with the extremely low yield of NH3.

[0009] To solve the above-mentioned problems, the inventors tackled technical challenges with the aim of realizing a process that eliminates the need for external procurement of NH3, and furthermore, an NH3 manufacturing process other than the conventional Haber-Bosch process. The present invention aims to provide a catalyst for ammonia production that generates ammonia from nitrogen oxides in a high yield in an exhaust gas atmosphere (in the presence of O2 and water vapor), and to provide a technology that can produce ammonia in a high yield. Furthermore, the present invention aims to provide a catalyst for ammonia production that does not easily lose activity even after prolonged use, a method for producing ammonia using the catalyst, and a method for denitrification of nitrogen oxides and denitrification equipment. [Means for solving the problem]

[0010] The gist of this invention is as follows: (1) The ammonia production catalyst of the present invention is provided on a support made of TiO2 Ag NO, which is supported in the presence of oxygen X This is a catalyst for ammonia production, which produces NH3 from a reducing agent. (2) In the ammonia production catalyst of the present invention, it is preferable that the amount of Ag loaded onto the support is 0.7 to 5% by mass of the total amount of the support and the Ag. (3)In the catalyst for ammonia production of the present invention, when used in the absence of water vapor, it is preferable that the crystal structure of the carrier is anatase type. (4) In the ammonia production catalyst according to the present invention (1) or (2) When used in the coexistence of oxygen and water vapor, it is preferable that the catalyst for ammonia production is a catalyst for producing NH3 from NO and a reducing agent, in which a metal is supported on a carrier having a rutile-type crystal structure. X It is preferably a catalyst for ammonia production. (5) In the catalyst for ammonia production of the present invention, it is preferable that the reducing agent is a hydrocarbon. (6) In the catalyst for ammonia production of the present invention, it is preferable that the hydrocarbon is C3H6.

[0011] (7) The ammonia production method of the present invention uses the ammonia production catalyst according to any one of (1) 、(2)、(4)~(6) and produces NH3 from NO and a reducing agent in one pot without concentrating NO in the coexistence of oxygen and water vapor. X It is characterized by the following. X It is characterized by producing NH3 from NO and a reducing agent. (8) The ammonia production method of the present invention uses the ammonia production catalyst described in (3) and NO in the absence of water vapor. X NO X And from the reducing agent NH 3 The invention is characterized by its manufacture. (9) In the ammonia production method of the present invention, it is preferable that the amount of Ag supported on the carrier is 0.7 to 1.5% by mass of the total amount of the carrier and Ag, and the ammonia production catalyst is used at 400 °C or higher. (10) In the ammonia production method of the present invention, it is preferable that the amount of Ag supported on the carrier is 1.5 to 5% by mass of the total amount of the carrier and Ag, and the ammonia production catalyst is used at a temperature lower than 400 °C. (11) The ammonia production apparatus of the present invention includes the ammonia production catalyst according to any one of (1) to (6) inside the reactor, and NO is provided on one side of the reactor. XThe reactor is characterized by having a supply section for the reducing agent and a supply section for the reducing agent, and having an outlet section on the other side of the reactor.

[0012] (12) The denitrification method of the present invention is (1) ~ (6) An ammonia production catalyst described in any of the above is installed in the upstream reactor, and an NH3-SCR catalyst is installed in the downstream reactor, and NO in the exhaust gas in the upstream reactor where the ammonia production catalyst is installed and oxygen and water vapor coexist. X More than 47.4% of it is converted to NH3 using the ammonia production catalyst and the reducing agent, and the converted NH3 is used as a reducing agent in the subsequent reactor to remove the remaining NO X This method is characterized by reducing the substance and performing denitrification in the subsequent reactor without externally injecting NH3 into the subsequent reactor.

[0013] (13) In the denitrification method of the present invention, it is preferable that the amount of Ag supported on the carrier is 0.7 to 1.5% by mass of the total amount of the carrier and the Ag, and that the ammonia production catalyst is used at 400°C or higher. (14) In the denitrification method of the present invention, it is preferable that the amount of Ag supported on the carrier is 1.5 to 5% by mass of the total amount of the carrier and the Ag, and that the ammonia production catalyst is used at a temperature of less than 400°C.

[0014] (15) In the denitrification method according to the present invention, C3H6 is used as the reducing agent according to any one of (12) to (14), and NO is provided downstream of the reactor in the subsequent stage. X The remaining NO is being monitored by a concentration monitor. X Based on the concentration, the remaining NH3 concentration monitored by an NH3 concentration monitor installed downstream of the aforementioned reactor, and the remaining C3H6 concentration monitored by a C3H6 concentration monitor, NO is calculated using correlation data between the NH3 yield and the conversion rate of the reducing agent C3H6. X It is preferable to adjust the amount of reducing agent C3H6 required to produce the desired NH3.

[0015] (16) The denitrification apparatus of the present invention comprises a front reactor and a rear reactor connected to the front reactor, wherein the ammonia production catalyst described in any of (1) to (6) is mounted in the front reactor, and the NO is located on one side of the reactor. X The reactor is characterized by having a supply section for the reducing agent and a supply section for the reducing agent, an outlet section on the other side of the reactor, and an NH3-SCR catalyst mounted in the downstream reactor. In the denitrification apparatus described in (17)(16), C3H6 is used as the reducing agent, and NO is provided downstream of the reactor in the subsequent stage. X The remaining NO is being monitored by a concentration monitor. X The concentration, the remaining NH3 concentration monitored by an NH3 concentration monitor installed downstream of the aforementioned reactor, and the C3H6 concentration monitor are all measured by these monitors. the law of nature Based on the monitored residual C3H6 concentration, NO is calculated using correlation data between NH3 yield and reducing agent C3H6 conversion rate. X It is preferable to have a control device or control device that adjusts the amount of reducing agent C3H6 required to produce the desired NH3. [Effects of the Invention]

[0016] According to the present invention, NO in exhaust gas X This invention provides a catalyst and method for ammonia production that can produce NH3 in high yield at atmospheric pressure and have a higher energy level for NO than for N2, thus enabling NH3 production with less energy than the conventional Haber-Bosch process which requires high temperature and pressure. Furthermore, this invention provides a catalyst and method for ammonia production that can produce ammonia in high yield.

[0017] According to the ammonia production method and denitrification method of the present invention, NO in exhaust gas where oxygen and water vapor coexist X Since NH3 can be produced from this process, it eliminates the need for air cryogenic separation equipment to obtain high-purity N2, or natural gas reforming processes or water electrolysis equipment to obtain H2, as is required in the conventional Haber-Bosch process. According to the denitrification method of the present invention, the transportation, storage, and injection facilities for the reducing agent NH3 supplied to the denitrification process in factory exhaust gas, as well as the related infrastructure facilities, become unnecessary, thereby contributing to a reduction in denitrification costs. [Brief explanation of the drawing]

[0018] [Figure 1] A schematic diagram showing the overall configuration of a denitrification apparatus equipped with a reactor on which the ammonia-producing catalyst according to the present invention is mounted. [Figure 2] A side view showing a reactor equipped with the ammonia production catalyst according to the present invention. [Figure 3] A schematic diagram showing the overall configuration of a conventional denitrification apparatus equipped with a conventional reactor containing an ammonia production catalyst. [Figure 4] A diagram illustrating the reaction pathway when producing ammonia using the catalyst according to the present invention. [Figure 5] This figure compares the temperature dependence of NH3 yield in the presence and absence of water vapor when using ZrO2, anatase-type TiO2, or rutile-type TiO2 as the support for Ag. [Figure 6] This figure shows the change in NH3 yield over time in the absence of water vapor when anatase-type TiO2 is used as the support for Ag. [Figure 7] This figure shows the effect of water vapor partial pressure on NH3 yield on a rutile-type TiO2 support bearing Ag. [Figure 8] This figure shows the effect of water vapor partial pressure on NH3 yield on anatase-type TiO2 support loaded with Ag. [Figure 9] This figure shows the effect of NH3 yield on the space velocity (SV) on a rutile-type TiO2 support bearing Ag. [Figure 10] This figure shows the effect of the space velocity (SV) on the NH3 yield on anatase-type TiO2 support loaded with Ag. [Figure 11] This figure shows the effect of the decrease in the partial pressure of the reducing agent (C3H6) on a rutile-type TiO2 support bearing Ag. [Figure 12]This figure shows the effect of the decrease in the partial pressure of the reducing agent (C3H6) on an anatase-type TiO2 support carrying Ag. [Figure 13] This figure shows the dependence of NH3 yield on the amount of catalyst metal (Ag) loaded onto the rutile-type TiO2 support. [Figure 14] This figure shows the dependence of the C3H6 conversion rate on the amount of catalyst metal (Ag) supported on the rutile-type TiO2 support. [Figure 15] This figure shows the change in C3H6 conversion rate depending on the NH3 yield of a catalyst in which 2% by mass of Ag is supported on a rutile-type TiO2 support. [Figure 16] This figure shows an example of a general control logic for determining the amount of reducing agent C3H6 required to generate a desired amount of NH3, by monitoring the residual NOx concentration using an environmental monitoring instrument installed in the chimney or other part of the discharge section shown in Figure 1, and monitoring the residual NH3 concentration and residual C3H6 concentration using an environmental monitoring instrument installed on the piping before the NH3 adsorption section. [Figure 17] Figure 16 shows an apparatus for implementing the control logic shown when the process according to the present invention is used only for exhaust gas denitrification and not for NH3 production. [Modes for carrying out the invention]

[0019] The following describes in detail the ammonia production catalyst, ammonia production method, and ammonia production apparatus according to this embodiment, with specific examples. Furthermore, the selective catalytic reduction denitrification (hereinafter referred to as NH3-SCR denitrification) and the selective catalytic reduction denitrification apparatus according to this embodiment, utilizing the ammonia production apparatus, will also be described.

[0020] Figure 1 is a schematic diagram showing the overall configuration of the NH3-SCR denitrification apparatus according to this embodiment. The NH3-SCR denitrification apparatus 1 has a reactor 2 for ammonia production. A reheater 3 for exhaust gas is connected upstream (pre-stage) of the reactor 2, and an induced draft fan 4 is connected upstream of the reheater 3. Upstream of the ventilator 4 is an exhaust gas supply source 5 connected to a bag filter or the like, which is connected to an exhaust gas source such as a factory. Nitrogen oxides (NOx) are emitted from the exhaust gas supply source 5. X The exhaust gas, which includes the above, passes through the ventilator 4 and the reheater 3 and is supplied to the reactor 2. Downstream of reactor 2 (the later stage), a denitrification reactor 6 containing an NH3-SCR catalyst and an ammonia adsorption means 7 are provided. The ammonia adsorption means 7 may be, for example, equipment that adsorbs leaked ammonia from the denitrification reactor 6 using activated carbon or the like. In this embodiment, exhaust gas from the exhaust gas supply source 5 is treated in the reactor 2 before being sent to the denitrification reactor 6. Therefore, the exhaust gas supply source 5 is the upstream equipment, and the denitrification reactor 6 is the downstream equipment. Ammonia adsorption means 7 and an outlet (chimney) 7A are provided downstream of the denitrification reactor 6, and an NH3 concentration monitor 6A is connected to the piping between the denitrification reactor 6 and the ammonia adsorption means 7. NO3 is supplied to the outlet 7A for environmental monitoring. X Concentration monitor 7B is connected, and NO is detected in the exhaust gas discharged from the discharge section 7A. X The concentration can be monitored. Note: NO X Regarding the concentration monitor 7B, it can be connected to the discharge section 7A even if the ammonia adsorption means 7 is omitted. However, if the ammonia adsorption means 7 is provided, it can also be connected to the piping upstream of the ammonia adsorption means 7.

[0021] A heat exchanger pipe 3a is provided inside the reheater 3. The inlet side of the heat exchanger pipe 3a is led out to the outside of the reheater 3 and connected to a high-pressure steam supply source 8 located outside the reheater 3. The high-pressure steam supply source 8 can supply high-pressure steam heated to a desired temperature to the heat exchanger pipe 3a. An exhaust pipe 3b is provided at the outlet side of the heat exchanger pipe 3a, allowing the high-pressure steam that has passed through the heat exchanger pipe 3a to be released into the atmosphere from the exhaust pipe 3b. The exhaust gas supplied from the ventilator 4 to the reheater 3 is temperature-controlled to the desired temperature by the meandering pipe 3a as it passes through the inside of the reheater 3, and after temperature control, it is supplied from the reheater 3 to the reactor 2.

[0022] Figure 2 shows the detailed structure of reactor 2. Reactor 2 has a vertical cylindrical body 2A, with a dome-shaped inlet 2B at the bottom and a dome-shaped outlet 2C at the top. An inlet pipe 10 is connected to the inlet 2B, and an outlet pipe 11 is connected to the outlet 2C. In reactor 2, the section where the inlet pipe 10 is connected to the inlet 2B is the exhaust gas supply section 2E, and the section where the outlet pipe 11 is connected to the outlet 2C is the gas outlet section 2F. The inlet pipe 10 is connected to the outlet side of the reheater 3, and the outlet pipe 11 is connected to the inlet side of the NH3-SCR denitrifier 6.

[0023] A supply pipe 12 is connected to the inlet pipe 10 at a point close to the reactor 2. This supply pipe 12 is connected to a reducing agent supply source 13. The reducing agent used here can be a hydrocarbon gas, for example, propylene gas (C3H6 gas). The tip of the supply pipe 12 connected to the inlet pipe 10 functions as a reducing agent supply section (supply nozzle) 12a for the reactor 2.

[0024] In the shell 2A of the reactor 2, a grating 15 is provided as a partition member near the inlet 2B. A retaining layer 16 is formed on the grating 15 by laying ceramic balls, and a catalyst layer 17 filled with granular catalyst is provided on the retaining layer 16. The grating 15 and the retaining layer 16 form a shelf floor, and the catalyst layer 17 is supported by the shelf floor. The catalyst layer 17 extends to near the upper end of the shell 2A, and a partition layer 18 made of laying ceramic balls is provided at the upper end of the catalyst layer 17. The catalyst layer 17 may be a structure in which the catalyst is fixed to a metal or ceramic honeycomb by coating or the like, or a structure in which the catalyst is molded into a honeycomb shape. In that case, the retaining layer 16 and the partition layer 18 may be omitted.

[0025] In reactor 2, the exhaust gas introduced from the inlet pipe 10 into the shell section 2A passes through the gaps between the ceramic balls to reach the catalyst layer 17, and then passes through the gaps between the catalyst particles in the catalyst layer 17. The gas that has passed through the gaps between the catalyst particles in the catalyst layer 17 passes through the gaps between the ceramic balls to reach the outlet pipe 11. The gas that reaches the outlet pipe 11 is supplied to the NH3-SCR denitrifier 6. The NH3-SCR denitrification apparatus 6 contains a catalyst suitable for NH3-SCR denitrification, such as activated carbon.

[0026] In the reactor 2, a first connecting pipe 19 is provided in a part of the shell 2A, penetrating the side wall of the shell 2, and a temperature measuring means 20 for measuring the temperature of the catalyst layer 17 is connected via this first connecting pipe 19. A second connecting pipe 21 is provided at the bottom of reactor 2, penetrating the peripheral wall of inlet 2B, and a third connecting pipe 22 is provided at the upper side of outlet 2C, penetrating the peripheral wall of outlet 2C. The pressure detection sensor of the pressure detector 23 is installed in the inlet section 2B via the second connecting pipe 21. The pressure detection sensor of the pressure detector 25 is installed in the outlet section 2C via the third connecting pipe 22.

[0027] Pressure detector 23 is a detector that detects the pressure at the bottom of reactor 2, and pressure detector 25 is a detector that detects the pressure at the top of reactor 2. The pressure measurement result at the bottom of reactor 2 corresponds to the pressure measurement result upstream of the catalyst layer 17, and the pressure at the top of reactor 2 corresponds to the pressure measurement result downstream of the catalyst layer 17. The pressure detectors 23 and 25 are connected to control equipment 26 such as a personal computer and a programmable controller, and are configured to measure and record the upstream and downstream pressures of the catalyst layer 17 measured by the pressure detectors 23 and 25, as well as to record and understand the calculation results such as the differential pressure between these pressures.

[0028] As a first example, catalyst 17 applied to reactor 2 can be catalyst particles in which metal particles such as Ag are supported on the surface of carrier particles made of rutile-type titanium oxide (TiO2). As a second example, catalyst 17 can be catalyst particles in which metal particles such as Ag are supported on the surface of carrier particles made of anatase-type titanium oxide (TiO2). As a third example, catalyst 17 can be catalyst particles in which metal particles such as Ag are supported on the surface of carrier particles made of zirconium oxide (ZrO2). Alternatively, a mixture of any of these first to third example catalyst particles can be used. When producing catalyst particles with Ag supported on the aforementioned carrier particles, each carrier particle is dissolved in an aqueous silver nitrate solution to obtain a predetermined amount of Ag support. The amount of Ag support can be adjusted by adjusting the concentration of the aqueous silver nitrate solution.

[0029] In the catalyst 17 described above, rutile-type titanium dioxide or anatase-type titanium dioxide can be used as a support, and Ag particles can be supported on the surface of these supports. In this case, the preferred amount of Ag to be supported can be selected in the range of 0.7 to 5% by mass relative to the total mass, which is the sum of the mass of the Ag to be supported and the mass of the support. When catalyst 17 is used in a temperature range of less than 400°C, the supported amount of Ag is preferably 1.5 to 5% by mass. When catalyst 17 is used in a temperature range of 400°C or higher, the supported amount of Ag is preferably 0.7 to 1.5% by mass. The carrier particles, as described above, are recovered by evaporation to dryness and then calcined in air at approximately 500°C for several hours to obtain the desired catalyst particles. The particle size of catalyst 17 can be adjusted to approximately 0.3 to 0.6 mm, for example.

[0030] In this specification, when specifying a range such as the range of component content or particle size, if the upper and lower limits are defined using "~", unless otherwise specified, it means that the upper and lower values ​​are included within that range. Therefore, the aforementioned 0.7~5 mass% means a range of 0.7 mass% or more and 5 mass% or less, and 1.5~5 mass% means a range of 1.5 mass% or more and 5 mass% or less.

[0031] In the NH3-SCR denitrification apparatus 1 shown in Figure 1, reactor 2 corresponds to the ammonia production apparatus, and the NH3-SCR denitrification apparatus 1 is mainly composed of reactor 2 and NH3-SCR denitrifier 6. Exhaust gas from the exhaust gas supply source 5 is supplied to the reheater 3a by the ventilator 4, and the temperature of the exhaust gas is adjusted by high-pressure steam supplied to the meander pipe 3a. The temperature-adjusted exhaust gas is then supplied to the reactor 2 via the inlet pipe 10. When supplying exhaust gas to the reactor 2 via the inlet pipe 10, a hydrocarbon gas is mixed with the exhaust gas as a reducing agent via the supply section 12a of the supply pipe 12. For example, propylene gas (C3H6) can be used as the hydrocarbon gas.

[0032] The exhaust gases to which this applies include, for example, NO, O2, CO, CO2, H2O, N2, SO2, etc. The exhaust gas comes into contact with the catalyst 17 housed inside the reactor 2 at a predetermined temperature and atmosphere, and reacts as shown in the following reaction equation to produce ammonia (NH3). NO+C3H6+13 / 4O2→NH3+3CO2+3 / 2H2O

[0033] Assuming a reaction mechanism in which exhaust gas comes into contact with catalyst 17 and is converted to NH3, the following equations (1) to (5) can be considered, and by summing up the equations shown in (1) to (5), the above reaction equation can be derived. (1) NO + 1 / 2O2 → NO2 (2) H2O → H+OH (3) NO2 + OH → HNO3 (4) Ag + HNO3 → AgNO3 + 1 / 2H2 (5)AgNO3+C3H6+9 / 4O2→Ag+NH3+3CO2+3 / 2H2O As an example of exhaust gas composition, one could describe exhaust gas with a composition such as NO: 980-1020 ppm, O2: 9.44-10.21%, H2O: 0% or 5.0%, and N2: balanced.

[0034] Ammonia (NH3) can be produced in high yield in the gas that has passed through catalyst 17 in reactor 2. As shown in the examples described later, for example, if the amount of Ag supported on the support is 1 to 1.5 mass% in a temperature range of around 400°C, ammonia can be produced from the exhaust gas in a high yield of 47.4% or more.

[0035] As shown in the reaction equation above, NO is oxidized to NO2 by Ag on the surface of the support. Furthermore, the -OH groups on the surface of the anatase-type TiO2 support are highly reactive with NO2, and NH3 is produced via nitrate rhizomes. In the case of a support made of rutile-type TiO2, where the surface -OH groups are less reactive, OH and H are generated on the support surface from coexisting water vapor, and NH3 is produced via nitrate rhizomes from the OH generated from coexisting water vapor and NO2. Therefore, according to the results above, NO in the presence of oxygen and water vapor X The reaction for ammonia production can be carried out in a single pot without concentration. Therefore, NO X This provides a method for producing ammonia by producing NH3 from a reducing agent.

[0036] In the ammonia production method using the catalyst described above, NO in the exhaust gas X This method allows for the production of NH3 at atmospheric pressure, and because NO has a higher energy level than N2, it has the advantage of producing NH3 at lower energy levels than the conventional Haber-Bosch process, which requires high temperature and pressure. The reaction pathway is explained below based on Figure 4.

[0037] As shown in Figure 4, the bond energy between elements N and N in N2 is 941.6 kJ / mol. The bond energy between elements N and H in NH3 is 444.1 kJ / mol. In the Haber-Bosch process, the reaction must proceed in a high-temperature, high-pressure environment, as shown by the upward arrow on the left side of Figure 4, from N2 to NH3. In contrast, the bond energy between elements N and O in NO is 626.8 kJ / mol. In the ammonia production method of this embodiment, the reaction equation for the conversion from NO to NH3 can be expressed as described above, so it can be understood that NH3 can be produced with lower energy than the Haber-Bosch process.

[0038] In the ammonia production method described above, NO is present in the exhaust gas where oxygen and water vapor coexist. X Since NH3 can be produced from this process, it eliminates the need for air cryogenic separation equipment to obtain high-purity N2, or natural gas reforming processes or water electrolysis equipment to obtain H2, as is required in the conventional Haber-Bosch process. Furthermore, the need for transporting and storing the reducing agent NH3 supplied to the denitrification process in factory exhaust gas, as well as the injection facilities and infrastructure for denitrification, is eliminated, contributing to a reduction in denitrification costs.

[0039] In the NH3-SCR denitrification apparatus 1 of this embodiment, the NH3 produced in the reactor 2 can be sent to the denitrification reactor 6 via the outlet pipe 11. In the denitrification reactor 6 containing the NH3-SCR catalyst, the NH3-SCR catalyst performs denitrification treatment using the supplied reducing agent, NH3. The NH3-SCR catalyst can be activated carbon, for example, and is removed by the reaction shown in the following formula. NO + NH3 + 1 / 2O2 → N2 + 3 / 2H2O

[0040] Figure 3 shows a schematic diagram of a selective catalytic reduction denitrification apparatus (NH3-SCR denitrification apparatus) configured based on the conventional Haber-Bosch process. A conventional NH3-SCR denitrification apparatus 30 has an exhaust gas supply source 32, a ventilator 33, a reheater 34, and a high-pressure steam supply source 35 upstream of the denitrification reactor 31 containing the NH3-SCR catalyst. The exhaust gas supply source 32 has the same configuration as the exhaust gas supply source 5 described earlier, and the ventilator 33 can have the same configuration as the ventilator 4 described earlier. The reheater 34 has the same configuration as the reheater described earlier, and the high-pressure steam supply source 35 can have the same configuration as the high-pressure steam supply source 8 described earlier.

[0041] In addition to these components, conventional NH3-SCR denitrification systems 30 require transportation and storage of the reducing agent NH3, as well as injection equipment for denitrification and related infrastructure. As shown in Figure 3, a reactor 46 is required to carry out the Haber-Bosch process using nitrogen from a cryogenic separator 41 equipped with an air supply means 40 and hydrogen from a steam reformer 45 equipped with a natural gas supply source 42 and a water supply source 43. A storage tank 48 is required to store the ammonia 47 produced in this reactor 46, a tank truck 49 is required to transport the ammonia, and an intermediate storage station 50 and dilution tank 51 are required for the ammonia transported by the tank truck 49. Furthermore, a tank truck 52 is required to transport the diluted ammonia from the dilution tank 51 to the site where the denitrification reactor 31 is installed, and an ammonia water tank 53 and ammonia water vaporizer 54 are required to be installed near the site. By sending ammonia water and compressed air from the ammonia water tank 53 at the site to the ammonia water vaporizer 54, ammonia can be supplied to the denitrification reactor 31.

[0042] As explained above, in the conventional NH3-SCR denitrification apparatus 30, various NH3 transport and storage equipment, denitrification injection equipment, and related infrastructure were required to supply NH3 to the denitrification reactor 31. In contrast, the multiple pieces of equipment and devices required in the conventional NH3-SCR denitrification apparatus 30 are unnecessary in the NH3-SCR denitrification apparatus 1 of the embodiment shown in Figure 1, contributing to a significant reduction in denitrification costs. Furthermore, since the catalyst described above does not lose activity even after repeated use, the NH3-SCR denitrification apparatus 1 can operate stably without frequent catalyst replacement. Also, reactor 2 is NO X This allows for the production of NH3 at low cost and high yield. [Examples]

[0043] The present invention will be described in more detail below with reference to examples, but the conditions in the examples are merely one example of conditions adopted to confirm the feasibility and effectiveness of the present invention, and the present invention is not limited to this one example of conditions. The present invention can adopt various conditions as long as they do not depart from the spirit of the invention and achieve the objectives of the present invention.

[0044] "Catalyst support" TiO2 (JRC-TIO-16 and -17) and ZrO2 (JRC-ZRO-6) were prepared. The rutile-type TiO2, JRC-TIO-16, was manufactured by Sakai Chemical Industry Co., Ltd., and had a specific surface area of ​​109 m². 2 / g, 30-50m after firing following Ag loading. 2 The value is / g. JRC-TIO-17 used P-25 manufactured by Degussa GmbH (Germany). P-25 was prepared by Evonik Japan Co., Ltd. as 70% anatase-type carrier + 20% rutile-type carrier + 10% amorphous-type carrier (hereinafter, P-25 may also be referred to as anatase-type TiO2). The specific surface area of ​​JRC-TIO-17 is 50m² regardless of whether Ag is loaded or not. 2 It is / g. JRC-ZRO-6 is amorphous hydrated ZrO2 prepared by Daiichi Rare Elements Chemical Industry Co., Ltd. using a hydrolysis method, with a specific surface area of ​​279 g / m². 2 After Ag-supported calcination, it changes to a tetrahedral crystalline phase, and its specific surface area is 94 g / m². 2 This is the result.

[0045] "Catalyst preparation (metal support)" • Method of carrying Ag When supporting Ag, each support was dissolved in an AgNO3 aqueous solution and adjusted to a predetermined Ag load (for example, 5% by mass of the total). The solid material recovered from the aqueous solution by evaporation to dryness was calcined in air at 500°C for 4 hours, and the resulting particles were mechanically crushed to adjust the particle size to 0.3-0.6 mm.

[0046] "Catalyst Analysis" The crystal structure and Ag particle size of the catalyst were analyzed using X-ray diffraction (D2 Phaser, Brucker, USA), Cu Kα radiation, and a Ni filter. "Catalytic reaction evaluation" Catalyst activity was evaluated using a quartz tube reactor (outer diameter 14 mm, tube thickness 1 mm, length 700 mm). The catalyst was placed in the center of the reactor. The catalyst volume was used to measure the space velocity (SV), which is typically 0.6 mL (SV = 10,000 h). -1A small amount (weighing approximately 0.3-0.5g) was installed. The reaction temperature was measured at the center of the catalyst packed bed using a sheathed tube with a protective sheath. All reaction evaluations were performed at atmospheric pressure.

[0047] A mixed gas of NO, C3H6, O2, H2O, and N2 is introduced from the top of the reactor at a rate of 100 mL / min (SV = 10,000 h). -1 (At that time) the gas was supplied, and the gas after the reaction was introduced from the bottom of the reactor into a 2.4 m gas cell in an FT-IR (Fourier Transform Infrared Spectrophotometer) system, and the constituent substances were measured as NH3 and C3H6.

[0048] The composition and flow rate conditions of the mixed gas used for evaluation are as follows: NO: 980~1020 ppm, C3H6: 0.50~0.52%, O2: 9.44~10.21%, H2O: 0% or 5.0%, N2: balanced, total flow rate: 100.0~102.5 mL / min, catalyst amount: 0.6 mL (SV: 10000~10300 h) -1 ).

[0049] The average NH3 production rate and average C3H6 consumption rate over a 30-minute period at a predetermined temperature were used to evaluate catalytic activity. NH3 yield (Y NH3 ) and C3H6 consumption rate (X C3H6 The following equations (1) and (2) were used to calculate the values ​​of NO and C3H6. Note that SV = Space Velocity. SV[h -1 The formula is calculated as: ] = supply gas flow rate [mL / h] / catalyst amount [mL].

[0050]

number

[0051]

number

[0052] Figure 5 shows a comparison of the temperature dependence of NH3 yield in the presence and absence of water vapor in Ag-supported ammonia production catalysts, when the support material is ZrO2, anatase-type TiO2 (P-25), or rutile-type TiO2. As shown in Figure 5, the reaction for ammonia production proceeded in all samples over a wide temperature range of 200°C to 380°C, and ammonia was successfully produced. As shown in Figure 5, the results indicate that in all samples, a peak in NH3 yield exists in a specific temperature range, and the NH3 yield gradually decreases as the temperature changes from the peak temperature range to lower or higher temperatures.

[0053] Furthermore, it was found that when using catalysts in which Ag is supported on anatase-type TiO2 (P-25) or rutile-type TiO2 supports, ammonia can be produced with a yield of approximately 30% in some cases. It should be noted that the fact that the ammonia production reaction proceeds using the above-mentioned catalysts, as shown in these test results, is itself a new finding, and this finding suggests that a technology capable of producing ammonia in high yields can be provided. Therefore, according to the results above, NO is produced regardless of the presence or absence of water vapor in the presence of oxygen. X The reaction for ammonia production could be carried out in one pot without concentration. Therefore, NO X This demonstrates that a method for producing ammonia by manufacturing NH3 from a reducing agent can be provided.

[0054] Figure 6 shows the change over time in the NH3 yield in the absence of water vapor in an Ag-supported ammonia production catalyst when the support is anatase-type TiO2. The results shown in Figure 6, compared with those shown in Figure 5, indicate that ammonia production catalysts with Ag supported on anatase-type TiO2 support tend to degrade over time when water vapor is not present.

[0055] Figure 7 shows the effect of reaction temperature and water vapor partial pressure on NH3 yield in an ammonia production catalyst in which Ag is supported on a rutile-type TiO2 support. As shown in Figure 7, the NH3 yield is low under the condition of 0% water vapor partial pressure, but it improves significantly under the condition of 2.5% to 15% water vapor partial pressure. In particular, under the condition of 10% to 15% water vapor partial pressure, an NH3 yield of over 30% was obtained by selecting the temperature conditions. The condition of 0% water vapor partial pressure corresponds to the case where dry gas is used as the exhaust gas. Furthermore, as demonstrated by the results of this test, the fact that the ammonia production reaction proceeds using the aforementioned catalyst is itself a new finding. Therefore, even when using dry gas with a low yield, the fact that the ammonia production reaction proceeds using the aforementioned catalyst has technical significance.

[0056] Figure 8 shows the effect of reaction temperature and water vapor partial pressure on NH3 yield in an ammonia production catalyst in which Ag is supported on an anatase-type TiO2 support. The results shown in Figure 8 indicate that a high NH3 yield can be obtained by selecting the reaction temperature under conditions where the water vapor partial pressure is between 0% and 10%. However, under conditions of 0% water vapor partial pressure, ammonia production catalysts using anatase-type TiO2 support exhibit degradation over time, as shown in Figure 6 above. Therefore, they are considered unsuitable for industrial applications where water vapor is present and continuous operation is required for extended periods.

[0057] Figure 9 shows the effect of space velocity (SV) on NH3 yield in an ammonia production catalyst in which Ag is supported on a rutile-type TiO2 support. As shown in Figure 9, the NH3 yield peak was found in all samples in the temperature range of 280–370°C, and the NH3 yield gradually decreased as the temperature changed from the peak temperature range to lower or higher temperatures. Furthermore, these ratios showed a similar trend at all spatial velocities within the tested range.

[0058] Figure 10 shows the effect of space velocity (SV) on NH3 yield in an ammonia production catalyst in which Ag is supported on an anatase-type TiO2 support. As shown in Figure 10, the results indicate that in all samples, a peak in NH3 yield was present in the temperature range of 320–350°C, and that the NH3 yield decreased as the temperature shifted from the peak temperature range to lower or higher temperatures. Furthermore, these ratios showed a similar trend across all spatial velocities within the tested range.

[0059] Figure 11 shows the effect of the reduction in partial pressure of the reducing agent (C3H6) in an ammonia production catalyst in which Ag is supported on a rutile-type TiO2 support. As shown in Figure 11, the NH3 yield peak was found in all samples in the temperature range of 330-360°C, and the NH3 yield decreased when the temperature changed from the peak temperature range to a lower or higher temperature. The results shown in Figure 11 indicate that the NH3 yield hardly changes at any reaction temperature, even when the partial pressure of the reducing agent changes from 0.28% to 0.51%.

[0060] Figure 12 shows the effect of the reduction in partial pressure of the reducing agent (C3H6) in an ammonia production catalyst in which Ag is supported on an anatase-type TiO2 support. As shown in Figure 12, the results indicate that in all samples, a peak in NH3 yield was present in the temperature range of 320-340°C, and that the NH3 yield decreased when the temperature changed from the peak temperature range to a lower or higher temperature. As shown in Figure 12, it was found that when the partial pressure of the reducing agent decreased from 0.51% to 0.28%, the NH3 yield decreased significantly at all reaction temperatures.

[0061] Figure 13 shows the results of evaluating the dependence of the amount of catalyst metal (Ag) supported and the temperature dependence on the NH3 yield in an ammonia production catalyst in which Ag is supported on a rutile-type TiO2 support. The results shown in Figure 13 indicate that the NH3 yield changes depending on the amount of Ag loaded onto the support and the reaction temperature. Furthermore, the labels “1st,” “2nd,” “3rd,” and “4th” in Figure 13 indicate the number of times the aforementioned temperature-dependent evaluation test ("catalytic reaction evaluation"), which was performed to obtain the results shown in Figure 5, was repeated on the same catalyst. These also represent the number of times the support used in the test was exposed to high temperatures of around 350-500°C.

[0062] For example, the data for "1.5wt%Ag_1st" shown in Figure 13 is a temperature-dependent result obtained by performing an evaluation test at a reaction temperature of 310°C using the method described in "Catalytic Reaction Evaluation" above, and then performing the same evaluation test while changing the reaction temperature as follows: 340°C → 360°C → 370°C → 380°C → 390°C → 400°C → 410°C → 430°C → 460°C. Subsequently, without changing the catalyst, an evaluation test was conducted at 270°C using the method described in "Catalytic Reaction Evaluation" above. Then, the reaction temperature was changed as follows: 280°C → 290°C → 300°C → 310°C → 320°C → 330°C → 340°C → 350°C → 360°C → 370°C → 380°C → 390°C → 400°C → 410°C → 420°C → 430°C → 440°C → 450°C → 460°C. The temperature dependence results obtained by conducting similar evaluation tests are shown in Figure 13 as the data indicated by "1.5wt%Ag 2nd".

[0063] When the amount of Ag supported on the rutile-type TiO2 support was 0.7 to 1.5% by mass of the total amount of Ag in the support and Ag combined, it was found that using the ammonia production catalyst at a temperature of 400°C or higher resulted in a higher NH3 yield. Therefore, when the amount of Ag supported on the rutile-type TiO2 support is 0.7 to 1.5% by mass, it is preferable to use the ammonia production catalyst at a temperature of 400°C or higher. The desirable catalyst temperature varies depending on the amount of Ag supported, but generally, a range of 400 to 500°C can be selected. When the amount of Ag supported on the rutile-type TiO2 support is 0.7 to 1.0 mass%, it can be seen that an excellent NH3 yield exceeding 47.4% can be obtained by adjusting the catalyst temperature.

[0064] Furthermore, it was found that when the amount of Ag supported on the rutile-type TiO2 support was 1.5 to 5% by mass of the total amount of Ag in the support and Ag combined, the NH3 yield was higher when the ammonia production catalyst was used at a temperature below 400°C. Therefore, when the amount of Ag supported on the rutile-type TiO2 support is 1.5 to 5% by mass, it is preferable to use the ammonia production catalyst at a temperature below 400°C.

[0065] Figure 14 shows the results of evaluating the dependence of the amount of catalyst metal (Ag) supported on the C3H6 conversion rate in an ammonia production catalyst in which Ag is supported on a rutile-type TiO2 support. The results shown in Figure 14 reveal that the C3H6 conversion rate changes depending on the amount of Ag loaded onto the support and the reaction temperature. A higher C3H6 conversion rate indicates improved reactivity.

[0066] Figure 15 shows the change in C3H6 conversion rate depending on the NH3 yield of a catalyst in which 2% by mass of Ag is supported on a rutile-type TiO2 support. A very strong correlation was observed between NH3 yield and C3H6 conversion rate.

[0067] "Study on material balance when applying an NH3 conversion process in the presence of oxygen." In the NH3-SCR denitrification apparatus 1 of this embodiment shown in Figure 1, the following equations (1) to (5) can be considered as the assumed reaction mechanism in which exhaust gas comes into contact with catalyst 17 and is converted to NH3. It was explained that the following reaction equation can be derived by summing up the equations shown in (1) to (5). (1) NO + 1 / 2O2 → NO2 (2) H2O → H+OH (3) NO2 + OH → HNO3 (4) Ag + HNO3 → AgNO3 + 1 / 2H2 (5)AgNO3+C3H6+9 / 4O2→Ag+NH3+3CO2+3 / 2H2O Reaction equation: NO + C3H6 + 13 / 4O2 → NH3 + 3CO2 + 3 / 2H2O

[0068] Therefore, based on this relationship, we will examine the material balance when applying the NH3 conversion process in the presence of oxygen below. In the NH3-SCR denitrification apparatus 1 shown in Figure 1, exhaust gas at 170°C is supplied from the exhaust gas supply means 5, reheated to 350.1°C in the reheater 3, and introduced into the reactor 2 through the inlet pipe 10. C3H6 at 40°C is supplied to the reactor 2 through the supply pipe 12 via the inlet pipe 10 as a reducing agent. Assuming the temperature of the catalyst layer 17 is 350°C, and that the gas temperature after denitrification in the denitrification reactor 6 is 349.8°C, we will proceed with this assumption.

[0069] In this case, for NO, C3H6, O2, CO, CO2, H2O, N2, NH3, SO2, HCl, and Ar, the amounts before regeneration heating, after reheating, the amount of reducing agent, the amount after NH3 conversion, the amount of injected NH3, and the amount after NH3-SCR denitrification are listed in Table 1 below. In the above case, the NH3 yield can be estimated at 47.48%, the denitrification rate at 90.4%, the C3H6 conversion rate at 93.6%, and the NH3 leak at less than 5 ppm.

[0070] [Table 1]

[0071] Based on the above relationships, the following control can be implemented in the NH3-SCR denitrification apparatus 1. Using the correlation data between the NH3 yield and the reducing agent C3H6 conversion rate as shown in Figure 15, the environmental monitoring NO equipped in the discharge section 7A in Figure 1 was used. X The remaining NO is being monitored by concentration monitor 7B. X Based on the concentration, NO contained in the exhaust gas X The amount of reducing agent C3H6 needed to produce the desired NH3 can be determined from the amount of [unspecified substance], and the amount of reducing agent C3H6 can be adjusted to an appropriate level.

[0072] In the NH3-SCR denitrification apparatus 1 shown in Figure 1, the ammonia adsorption means 7 may be omitted. In this case, an environmental monitoring NO is connected to the chimney of the discharge section 7A in Figure 1. XBased on the remaining NH3 concentration monitored by the concentration monitor 7B, the NO contained in the exhaust gas is calculated. X Determine the quantity. Then, using the aforementioned correlation data, the aforementioned NO X The amount of reducing agent C3H6 needed to produce the desired NH3 can be determined from the quantity, and the amount of reducing agent C3H6 can be adjusted to an appropriate level.

[0073] In the NH3-SCR denitrification apparatus 1 shown in Figure 1, when an ammonia adsorption means 7 is provided, an environmental monitoring NO is connected to the piping before it. X In some cases, a concentration monitor 7B may be installed. In this case, the NO content in the exhaust gas is determined based on the monitored residual NH3 concentration. X Determine the quantity, and using the aforementioned correlation data, the aforementioned NO X The amount of reducing agent C3H6 needed to produce the desired NH3 can be determined from the quantity, and the amount of reducing agent C3H6 can be adjusted to an appropriate level.

[0074] In the NH3-SCR denitrification system 1 shown in Figure 1, an environmental monitoring device for NO is installed in the discharge section 7A. X Remaining NO measured by concentration monitor 7B X The concentration can be monitored using the NH3 concentration monitor 6A, which is installed on the piping before the ammonia adsorption means 7, or the remaining NH3 concentration can be monitored using the C3H6 concentration monitor 6B.

[0075] Figure 17 shows a modified version of the NH3-SCR denitrification apparatus 1 shown in Figure 1. In this example, the NH3-SCR denitrification apparatus 60 omits the ammonia adsorption means 7 that was provided in the NH3-SCR denitrification apparatus 1, and has a structure in which an NH3 concentration monitor 6A and a C3H6 concentration monitor 6B are connected to the discharge section 7A. As shown in Figure 17, if there is no ammonia adsorption means 7, NO X Both the NH3 concentration and the NO concentration are monitored at the discharge unit 7 by an NH3 concentration monitor 6A, a C3H6 concentration monitor 6B, and NO X The concentration can be monitored using the concentration monitor 7B.

[0076] In the NH3-SCR denitrification apparatus 60 shown in Figure 17, a flow control valve 61 is incorporated into the reducing agent supply source 13, and a calculation device (control device) 62 capable of controlling this flow control valve 61 is provided. According to the calculation results of the calculation device 62, the amount of reducing agent sent from the supply source 13 to the upstream reactor 2 can be adjusted by adjusting the opening degree of the flow control valve 61. Also, NO X Residual NO measured by concentration monitor 7B, NH3 concentration monitor 6A, and C3H6 concentration monitor 6B X The concentration observation results, the residual NH3 concentration observation results, and the C3H6 concentration observation results are all input to the calculation unit 62. The calculation unit 62 then processes the aforementioned residual NO X Based on the concentration observation results and the remaining NH3 concentration observation results, the amount of reducing agent supplied from the supply source 13 is adjusted by adjusting the flow control valve 61 according to the calculation results described later. The calculation device 62 can be a personal computer, programmable controller, or the like, which is capable of storing information and has functions to perform calculations and make decisions according to the stored information. Furthermore, the flow control valve 61 may be either an electrically operated valve or a pneumatically operated valve.

[0077] For example, NO production depends on the type of catalyst used for ammonia production, the reaction temperature, etc. X Based on the amounts, the relationship shown in Figure 15, which illustrates a catalyst in which 2 mass% Ag is supported on a rutile-type TiO2 support as an example, is stored in the computing device 62. Based on this information, the amount of reducing agent C3H6 required to generate the desired NH3 is determined by calculations included in the control logic shown in Figure 16, and the amount of reducing agent supplied can be adjusted by operating the flow rate control valve 61 described above. Furthermore, the flow control valve 61 may be either an electrically operated valve or a pneumatically operated valve.

[0078] If a rutile-type TiO2 support bearing more than 2 mass% of Ag is used, a relationship similar to the one shown in Figure 15 should be determined for the rutile-type TiO2 support bearing more than 2 mass% of Ag and stored in the computing device 62. Alternatively, if a rutile-type TiO2 support bearing more than 2 mass% of Ag and a rutile-type TiO2 support bearing 2 mass% of Ag are mixed and used, a relationship similar to the one shown in Figure 15 should be determined in advance using test supports corresponding to the mixing ratio and stored in the computing device 62, and this information should be used. Therefore, in the NH3-SCR denitrification apparatus 60 shown in Figure 17, NO contained in the exhaust gas X By determining the amount of [unclear] and adjusting the amount of reducing agent C3H6 supplied to reactor 2, NH3 can be produced in the desired yield.

[0079] Figure 16 is a flowchart showing an example of a schematic control logic for producing a desirable amount of NH3 while controlling the supply amount of the reducing agent (C3H6) using the NH3-SCR denitrification apparatus 60 shown in Figure 17. NO X Remaining NO from concentration monitor 7B X The concentration observation results are sent to the calculation unit 62 (first step ST1), and the remaining NH3 concentration observation results are sent from the NH3 concentration monitor 6A to the calculation unit 62 (second step ST2). In the calculation unit 62, when the denitrification rate in reactor 6 is p × 100%, the amount of NH3 consumed in denitrification of reactor 6 = {p / 1-p} × residual NO in the discharge section. X Since the quantitative relationships are stored, the amount of NH3 to be produced in reactor 2 can be calculated based on the results obtained in the first step ST1 and the second step ST2 (third step ST3).

[0080] In step 3, ST3, the calculated value is recognized as the amount of NH3 to be produced in reactor 2 in step 4, ST4, and in step 5, ST5, the amount of NH3 to be produced in reactor 2 / generated NO xBased on the quantitative relationship, the NH3 yield can be determined in step 6 (ST6), and the C3H6 conversion rate can be calculated in step 8 (ST8) using the correlation formula shown in Figure 15 in step 7 (ST7).

[0081] Furthermore, the calculation unit 62 receives the remaining C3H6 concentration observation result from the C3H6 concentration monitor 6B (step 9 ST9), and the relationship remaining C3H6 concentration / (1 - C3H6 conversion rate / 100) = C3H6 supply amount is stored along with the C3H6 conversion rate calculated in step 8 ST8. Using this relationship, the required amount of C3H6 to be added is determined in step 10 ST10 and can be recognized as shown in step 11 ST11. For example, Figure 15 shows the change in C3H6 partial pressure depending on the NH3 yield of a catalyst in which 2% by mass of Ag is supported on a rutile-type TiO2 support, as explained earlier. Therefore, based on the relationship y = 1.9744X - 5.7557 obtained from the relationship shown in Figure 15, the amount of C3H6 added can be determined from the NH3 yield. Note: Occurrence No. X The amount changes sequentially, so the generated NO X The quantity is monitored over time as shown in step 12 ST12, repeatedly used in the calculation of step 5 ST5, and sequentially used in the calculations from step 6 ST6 onward, enabling stable control. [Explanation of symbols]

[0082] 1...Selective catalytic reduction denitrification apparatus (NH3-SCR denitrification apparatus), 2...Reactor (ammonia production apparatus), 2A...Body section, 2B...Inlet section, 2C...Outlet section, 2E...Supply section, 2F...Outlet section, 3...Reheater, 5...Exhaust gas supply means, 6...(NH3-SCR) denitrification reactor, 10...Inlet pipe, 11...Outlet pipe, 12...Supply pipe, 12a...Supply section (supply nozzle), 17...Catalyst layer, 20...Temperature measuring means, 23, 25...Pressure detector, 26...Control equipment, 62...Calculation device (regulation device).

Claims

1. TiO ２ Ag is supported on a carrier made of the following material, in the presence of oxygen, NO Ｘ and reducing agent NH ３ A catalyst for ammonia production, which is used to manufacture [a certain substance].

2. The ammonia production catalyst according to claim 1, wherein the amount of Ag loaded onto the carrier is 0.7 to 5% by mass of the total amount of the carrier and the Ag.

3. The ammonia production catalyst according to claim 1 or 2, wherein the crystal structure of the support used in the absence of water vapor is of the anatase type.

4. Ag is supported on a support having a rutile-type crystal structure, under the presence of oxygen and water vapor, NO Ｘ and reducing agent NH ３ A catalyst for ammonia production according to claim 1 or claim 2, which is used to produce [the specified product].

5. The catalyst for ammonia production according to any one of claims 1 to 4, wherein the reducing agent is a hydrocarbon.

6. The aforementioned hydrocarbon is C ３ H ６ The ammonia production catalyst according to claim 5.

7. Using the catalyst for ammonia production according to any one of claims 1, claim 2, and claims 4 to 6, NO Ｘ is used to produce NH Ｘ from NO ３ and a reducing agent in one pot without concentrating NO to produce ammonia.

8. A method for producing ammonia using the ammonia production catalyst described in Claim 3, wherein NOx is produced in a single pot without concentrating NOx in the absence of water vapor, and NH3 is produced from NOx and a reducing agent.

9. The ammonia production method according to claim 7 or claim 8, wherein the amount of Ag loaded onto the carrier is 0.7 to 1.5% by mass of the total amount of the carrier and the Ag, and the ammonia production catalyst is used at 400°C or higher.

10. The ammonia production method according to claim 7 or claim 8, wherein the amount of Ag loaded onto the carrier is 1.5 to 5% by mass of the total amount of the carrier and the Ag, and the ammonia production catalyst is used at a temperature of less than 400°C.

11. The catalyst for ammonia production described in any one of claims 1 to 6 is provided inside the reactor, and the NO is located on one side of the reactor. Ｘ An ammonia production apparatus comprising a supply section for the ammonia and a supply section for the reducing agent, with an outlet section on the other side of the reactor.

12. The ammonia production catalyst according to any one of claims 1 to 6 is installed in the upstream reactor, and NH is added to the downstream reactor. ３ - NO in exhaust gas where oxygen and water vapor coexist in the reactor preceding the reactor equipped with the ammonia production catalyst, which is equipped with an SCR catalyst. Ｘ More than 47.4% of the NH is produced using the ammonia production catalyst and the reducing agent. ３ NH converted to ３ The remaining NO is used as a reducing agent in the subsequent reactor. Ｘ By reducing it, NH is supplied to the subsequent reactor. ３ A denitrification method that performs denitrification in the subsequent reactor without external injection of the substance.

13. The denitrification method according to claim 12, wherein the amount of Ag loaded onto the carrier is 0.7 to 1.5% by mass of the total amount of the carrier and the Ag, and the ammonia production catalyst is used at 400°C or higher.

14. The denitrification method according to claim 12, wherein the amount of Ag loaded onto the carrier is 1.5 to 5% by mass of the total amount of the carrier and the Ag, and the ammonia production catalyst is used at a temperature of less than 400°C.

15. C as the reducing agent ３ H ６ Using the above-mentioned downstream reactor, NO is installed downstream of the downstream reactor. Ｘ The remaining NO is being monitored by a concentration monitor. Ｘ The concentration and the NH installed downstream of the aforementioned reactor ３ The remaining NH is being monitored by a concentration monitor. ３ Poles and C ３ H ６ The remaining carbon is being monitored by a concentration monitor. ３ H ６ Based on the concentration, NH ３ Yield and reducing agent C ３ H ６ By using the correlation data of the conversion rate, NO Ｘ Desirable NH ３ Reducing agent C required to produce ３ H ６ A denitrification method according to any one of claims 12 to 14, wherein the amount is adjusted.

16. It comprises a preceding reactor and a subsequent reactor connected to the preceding reactor, The catalyst for ammonia production described in any one of claims 1 to 6 is installed in the reactor in the preceding stage, and the NO is located on one side of the reactor. Ｘ A supply section for the reducing agent and a supply section for the reducing agent are provided, and an outlet section is provided on the other side of the reactor, In the subsequent reactor, NH ３ - A denitrification system equipped with an SCR catalyst.

17. C as the reducing agent ３ H ６ Using the above-mentioned downstream reactor, NO is installed downstream of the downstream reactor. Ｘ The remaining NO is being monitored by a concentration monitor. Ｘ The concentration and the NH installed downstream of the aforementioned reactor ３ The remaining NH is being monitored by a concentration monitor. ３ Poles and C ３ H ６ The remaining C3H is being monitored by a concentration monitor. ６ Based on the concentration, NH ３ Yield and reducing agent C ３ H ６ By performing calculations using correlation data of conversion rates, NO Ｘ Desirable NH ３ Reducing agent C required to produce ３ H ６ The denitrification apparatus according to claim 16, further comprising an adjustment device for adjusting the amount.

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