JP2012071262A - Deterioration regeneration method and deterioration regeneration system of denitration catalyst - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable to perform the regeneration treatment of a denitration catalyst in the more suitable condition and regeneration treatment time.SOLUTION: In the exhaust gas treatment which adds an ammonia based substance to the exhaust gas from a combustion equipment 102, and performs the decomposition of nitrogen oxide by a denitration catalyst 104, when the ventilation by a purge gas supply means 38 and the heating by a purge gas heating means 40 perform the regeneration treatment to the deterioration by sulfur oxide of the denitration catalyst 104 at the time of the operation stop of the combustion equipment 102, the regeneration treatment is controlled based on the flow rate of a purge gas at the time of the regeneration of the denitration catalyst 104 by the ventilation (superficial velocity), the regeneration temperature of the denitration catalyst 104 by heating, and the regeneration treatment time to the denitration catalyst 104.

Description

  The present invention relates to a degradation regeneration method and degradation regeneration system for a denitration catalyst.

  A denitration apparatus that removes nitrogen oxides contained in exhaust gas from combustion engines such as diesel engines and gas turbines is used. As a denitration method, by supplying ammonia as a reducing agent to a titanium / vanadium catalyst provided in an exhaust gas passage, it is reacted with nitrogen oxide (NOx), and decomposed into water and nitrogen as in chemical formula (1). An ammonia selective catalytic reduction method (SCR method) is known. Further, a method is employed in which urea is injected into the exhaust gas passage and ammonia is supplied to the catalyst by decomposing urea as in chemical formula (2).

In such a denitration apparatus, it is necessary to prevent the blockage of the apparatus caused by acid ammonium sulfate precipitation due to unreacted ammonia or corrosion due to sulfur oxide SO ₃ .

  For example, when the incinerator is shut down, the duct on the outlet side and the inlet side of the denitration reactor is closed to shut off the exhaust gas flow path, and the gas processing generated by poisoning substances deposited on the denitration catalyst is provided in the circulation system A process is disclosed in which the denitration catalyst is regenerated by decomposing and removing it by an apparatus to regenerate gas, heating it again to 350 ° C. to 550 ° C., and retransmitting it to the denitration reactor (see Patent Document 1).

  Further, a process is disclosed in which a nozzle with a gas heating device is provided immediately before the denitration catalyst, and the exhaust gas containing the ammoniacal reducing agent is heated to 250 ° C. to 500 ° C. to regenerate the denitration catalyst (see Patent Document 2).

  In addition, in the regeneration treatment of denitration catalysts for metal oxides containing titanium, vanadium, tungsten, molybdenum, etc., a technology for controlling and controlling the temperature of the denitration catalyst constantly when heating and supplying the regeneration gas ( Patent Document 3), a technique for controlling the temperature rise rate of the denitration catalyst (see Patent Documents 4 and 5), and a technique for controlling the regeneration processing time (see Patent Document 5) are disclosed.

JP 2008-73665 A JP 2001-113131 A JP 2001-310114 A Japanese Patent No. 3779889 JP 2008-748 A

  By the way, in a deterioration regeneration system that regenerates a denitration catalyst for exhaust gas in a state where a power engine such as a ship is stopped, it is desired to perform more optimal regeneration processing in a shorter time. In addition, there is a demand for a deteriorated reproduction system that can perform reproduction processing for a suitable time.

  The method of deteriorating and regenerating a denitration catalyst according to claim 1 is an exhaust gas treatment in which an ammonia substance is added to exhaust gas from a combustion device and nitrogen oxides are decomposed by the denitration catalyst, and when the operation of the combustion device is stopped When performing regeneration treatment for deterioration due to sulfur oxides of the denitration catalyst by blowing by and heating by heating means, the regeneration space velocity of the denitration catalyst by blowing and the regeneration temperature of the denitration catalyst by heating, The regeneration process is controlled based on the regeneration process time for the denitration catalyst. As a result, the regeneration treatment of the denitration catalyst can be performed under more appropriate conditions and regeneration treatment time.

  In the denitration catalyst deterioration regeneration method corresponding to claim 2, the regeneration processing time is controlled to be shortened as the regeneration temperature becomes higher. Thereby, the regeneration process time can be appropriately controlled according to the regeneration process temperature of the denitration catalyst.

  In the denitration catalyst deterioration regeneration method corresponding to claim 3, the regeneration temperature is set in a range of 300 ° C. or more and 600 ° C. or less. More preferably, the temperature is in the range of 350 ° C. or higher and 500 ° C. or lower. As a result, the optimum regeneration process can be performed while preventing thermal degradation of the denitration catalyst within the effective regeneration process time.

  In the denitration catalyst deterioration regeneration method corresponding to claim 4, the denitration catalyst is heated by the heating means at a temperature rising rate exceeding 60 ° C./h. Thereby, the regeneration treatment of the denitration catalyst can be performed in a shorter time.

  In the denitration catalyst deterioration regeneration method corresponding to claim 5, the denitration catalyst contains niobium (Nb). In particular, the niobium (Nb) content is preferably 0.001 wt% or more and 10 wt% or less with respect to the denitration catalyst 104. Thereby, higher heat resistance can be exhibited. For example, even if regeneration treatment is performed in a temperature range of 300 ° C. or higher and 600 ° C. or lower or heating is performed at a temperature rising rate exceeding 60 ° C./h, thermal degradation of the denitration catalyst is prevented. Can be suppressed. On the other hand, when the content of niobium (Nb) exceeds 5 wt%, the effect of improving heat resistance is saturated, and there is a risk of causing economic disadvantage.

  In the denitration catalyst deterioration regeneration system corresponding to claim 6, a combustion device, an exhaust gas path for discharging exhaust gas from the combustion device, a denitration catalyst provided in the exhaust gas channel, and between the combustion device and the denitration catalyst An ammonia substance addition means for adding an ammonia substance to the exhaust gas provided in the exhaust gas path, a blowing means for blowing air to the denitration catalyst, a heating means for heating the denitration catalyst, and the denitration catalyst by blowing air The regeneration control means for controlling the regeneration process for the denitration catalyst when the combustion equipment is stopped based on the regeneration space-time speed, the regeneration temperature of the denitration catalyst by the heating, and the regeneration treatment time for the denitration catalyst And comprising. As a result, the regeneration treatment of the denitration catalyst can be performed under more appropriate conditions and regeneration treatment time.

In the denitration catalyst deterioration regeneration system corresponding to claim 7, the regeneration space-time speed is made smaller than the operation space-time speed due to exhaust gas during operation of the combustion equipment. Normally, in a marine diesel engine, the superficial velocity of exhaust gas during operation of the combustion equipment is 10,000 to 25000 h ⁻¹ , but the superficial velocity required as the purge gas is within a suitable purge gas temperature range and effective regeneration processing time. The range is about 1000 to 5000 h ⁻¹ . Thus, the regeneration treatment of the denitration catalyst can be performed even with a small purge gas flow rate.

  In the denitration catalyst deterioration regeneration system corresponding to claim 8, the blower means arranges the denitration catalyst above the heating means and generates a natural draft force by heating by the heating means to blow. Accordingly, the purge gas can be sent to the denitration catalyst without using an apparatus such as a compressor or a blower, and it is possible to realize power saving and simplification of equipment in the regeneration process.

  According to a ninth aspect of the present invention, the combustion equipment is a diesel engine. The denitration catalyst deterioration regeneration system can be applied to a ship or other moving diesel engines. Of course, you may apply to the combustion apparatus of a diesel engine, for example, the apparatus (direct injection type otto engine etc.) which performs intermittent combustion. Further, the present invention can be applied to general combustion equipment such as garbage incinerators and thermal power generation facilities other than ships.

  In the denitration catalyst deterioration regeneration system corresponding to claim 10, the air blowing means is a means used for starting the diesel engine or a means equipped in the diesel engine. For example, a starting compressor or auxiliary blower for a combustion engine can be used as a blower for purge gas. Thus, the regeneration treatment of the denitration catalyst can be performed under the optimum conditions using the equipment already provided in the conventional exhaust gas denitration system.

  In the denitration catalyst deterioration regeneration system corresponding to claim 11, the denitration catalyst contains niobium (Nb). In particular, the niobium (Nb) content is preferably 0.001 wt% or more and 10 wt% or less with respect to the denitration catalyst 104. Thereby, higher heat resistance can be exhibited. For example, even when heating is performed at a temperature rising rate exceeding 60 ° C./h, thermal degradation of the denitration catalyst can be suppressed. On the other hand, when the content of niobium (Nb) exceeds 5 wt%, the effect of improving heat resistance is saturated, and there is a risk of causing economic disadvantage.

  In the deterioration regeneration system for a denitration catalyst corresponding to claim 12, the catalyst deterioration prediction means is further provided, and the regeneration processing is performed based on the predicted value of the deterioration prediction means. For example, it is possible to predict the deterioration of the denitration catalyst more accurately based on the relationship with the oxidation rate of sulfur oxide that is closely related to the deterioration of the denitration catalyst. Thereby, the regeneration process for the deterioration of the denitration catalyst can be executed at an appropriate timing and condition.

  In the denitration catalyst deterioration regeneration system corresponding to claim 13, the regeneration control means can set a plurality of regeneration treatment times for the denitration catalyst. For example, it is possible to select a regeneration process that takes one night and a rapid regeneration process of 2 hours according to the operation schedule of the ship.

  In the denitration catalyst deterioration regeneration system corresponding to claim 14, the regeneration process of the denitration catalyst is started within one hour after the operation of the combustion equipment is stopped. The regeneration treatment of the denitration catalyst is preferably started before the temperature of the denitration catalyst reaches 150 ° C. or less after the combustion engine is stopped, and specifically, it is preferably started within one hour. is there. As a result, when the regeneration process is executed, the time for raising the temperature of the denitration catalyst again can be shortened, and the entire regeneration process time can also be shortened. In addition, the power consumed in the reproduction process can be reduced.

  According to the degradation regeneration method and degradation regeneration system of the denitration catalyst of the present invention, the regeneration treatment of the denitration catalyst can be performed under more appropriate conditions and regeneration treatment time.

  Further, by controlling so that the regeneration processing time becomes shorter as the regeneration temperature becomes higher, the regeneration processing time can be appropriately controlled according to the regeneration processing temperature of the denitration catalyst.

  In addition, by setting the regeneration temperature in the range of 300 ° C. or more and 600 ° C. or less, it is possible to perform optimum regeneration processing while preventing thermal deterioration of the denitration catalyst within the effective regeneration processing time.

  Further, the denitration catalyst can be regenerated in a shorter time by heating the denitration catalyst at a temperature rising rate exceeding 60 ° C./h by the heating means. In particular, by including niobium (Nb) in the denitration catalyst, thermal degradation of the denitration catalyst can be suppressed even if heating is performed at a temperature rising rate exceeding 60 ° C./h.

  Further, the regeneration space temperature can be made smaller than the operation space velocity due to the exhaust gas during operation of the combustion equipment, so that the regeneration treatment of the denitration catalyst can be performed even with a small purge gas flow rate.

  In addition, the blower means realizes power saving and simplification of equipment in the regeneration process by arranging a denitration catalyst on the upper part of the heating means and generating natural draft force by heating by the heating means to blow. Can do.

  Further, the denitration catalyst deterioration regeneration system can be applied to a ship or other moving diesel engines.

  Further, the air blowing means is already provided in the means used for starting the diesel engine or the conventional exhaust gas denitration system by using the means used for starting the diesel engine or the means equipped in the diesel engine. The equipment can be used to regenerate the denitration catalyst under optimum conditions.

  Further, by further comprising catalyst deterioration prediction means and performing the regeneration process based on the predicted value of the deterioration prediction means, the regeneration process for the deterioration of the denitration catalyst can be executed at an appropriate timing and conditions.

  In addition, the regeneration control means can set a plurality of regeneration treatment times for the denitration catalyst, for example, depending on the ship operation schedule, the regeneration process over one night, the rapid regeneration process for 2 hours, Can be selected.

  In addition, by starting the regeneration process of the denitration catalyst within one hour after the operation of the combustion equipment is stopped, the time for raising the temperature of the denitration catalyst again when performing the regeneration process can be shortened. Time can be shortened. In addition, the power consumed in the reproduction process can be reduced.

It is a figure which shows the main structures of the denitration system in embodiment of this invention. It is a figure which shows the reaction system of a nitrogen oxide and a reducing agent. It is a figure which shows the reaction system of a sulfur oxide and a reducing agent. It is a figure which shows the structure of the denitration system in embodiment of this invention. It is a flowchart which shows the degradation reproduction process in embodiment of this invention. It is a figure which shows the relationship between the purge gas flow rate in the deterioration regeneration process of a denitration catalyst, and the activity of the denitration catalyst after a regeneration process. It is a figure which shows the structure of the reproduction | regeneration processing system in embodiment of this invention. It is a figure which shows the structure of the reproduction | regeneration processing system in the modification 1. It is a figure which shows the structure of the reproduction | regeneration processing system in the modification 2. FIG. 10 is a diagram illustrating a configuration of a reproduction processing system in a third modification. FIG. 10 is a diagram illustrating a configuration of a reproduction processing system in a fourth modification. FIG. 10 is a diagram showing a configuration of a reproduction processing system in Modification 5. It is a flowchart which shows the degradation prediction process in embodiment of this invention. It is a figure explaining the degradation prediction process in embodiment of this invention. It is a figure which shows the relationship between reaction temperature and the oxidation rate of sulfur dioxide. It is a diagram showing a relationship between the activity of the denitration activity and / or SO ₂ oxidation activity deposition amount and the denitration catalyst of sulfur deposits.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a main configuration of an exhaust gas denitration system 100 according to an embodiment of the present invention. As shown in FIG. 1, the denitration system 100 includes a combustion device 102, a gas passage 103, a denitration catalyst 104, a reducing agent supply unit 106, a control unit 108, and a purge gas supply unit 110.

  The combustion device 102 is an internal combustion engine or a gas turbine, for example, a marine diesel engine. The denitration system 100 is used to remove nitrogen oxides contained in the exhaust gas discharged from the combustion device 102.

The denitration catalyst 104 is a catalyst for decomposing nitrogen oxide (NOx) contained in exhaust gas by reacting with ammonia. The denitration catalyst 104 is made of a titanium / vanadium metal. For example, a titanium oxide TiO ₂ catalyst using vanadium (V), molybdenum (Mo), or tungsten (W) as an active component is used. In particular, in the present embodiment, it is preferable that the denitration catalyst 104 contains niobium (Nb) as an additive. The content of niobium (Nb) is preferably 0.001 wt% or more and 10 wt% or less with respect to the denitration catalyst 104. By setting the content in this range, the heat resistance of the denitration catalyst 104 can be improved, and a regeneration treatment at a higher temperature and a faster temperature increase rate can be applied. That is, the addition of niobium (Nb) suppresses sintering (sintering) of the titania particles contained in the denitration catalyst 104 and other components, maintains the fine structure of the pores of the denitration catalyst 104, and provides corrosion resistance and heat resistance. It is estimated that the resistance and impact resistance can be improved. In particular, by containing niobium (Nb) in an amount of 0.01 wt% or more, higher heat resistance can be exhibited. On the other hand, when the content of niobium (Nb) exceeds 5 wt%, the effect of improving heat resistance is saturated, and there is a risk of causing economic disadvantage.

  The denitration catalyst 104 is disposed in the gas passage 103. The denitration catalyst 104 preferably has a structure in which flat plates and catalyst thin tubes are bundled in order to increase the reaction area. For example, a honeycomb structure is preferable.

The reducing agent supply unit 106 can include a urea tank, a pump, a urea valve, a compressor, an air valve, an injection nozzle, and piping. The reducing agent supply unit 106 is provided to supply urea (urea water) and air to the gas passage 103 via the injection nozzle. For example, urea (urea water) is injected into the gas passage 103 as a reducing agent, and ammonia generated by the decomposition reaction represented by the chemical formula (2) is supplied to the surface of the denitration catalyst 104. The urea tank is a tank that stores urea water ((NH ₂ ) ₂ CO + H ₂ O). A pump is provided in the middle of piping which connects a urea tank and an injection nozzle. The pump applies pressure to the urea water stored in the urea tank, and supplies the urea water to the gas passage 103 via the pipe and the injection nozzle. The urea valve is provided downstream of the pump of the piping, and supplies / blocks urea water pressurized by the pump to the injection nozzle. A compressor is provided in the middle of piping connected to an injection nozzle. A compressor pressurizes air and supplies it to an injection nozzle through piping. Note that when the denitration system 100 is mounted on a ship, air in an air pipe provided in the ship may be used instead of the compressor. The air valve is provided downstream of the compressor of the pipe, and supplies and blocks air pressurized by the compressor to the injection nozzle. The injection nozzle is a nozzle for injecting urea water from the reducing agent supply unit 106 into the gas passage 103. The injection nozzle is formed by processing the tip of the pipe, or is configured by connecting another member to the tip of the pipe. The injection nozzle is disposed upstream of the denitration catalyst 104 in the gas passage 103. The injection nozzle mixes urea water and air, and injects urea water mixed in advance with air into the gas passage 103 with an appropriate supply pressure. However, the reducing agent is not limited to urea (urea water).

  The control unit 108 controls the denitration system 100 in an integrated manner. The control unit 108 can be configured by a general computer including a CPU, a memory, an input device, an output device, an external interface, and the like. The control unit 108 reads out and executes a control program stored in advance in a memory by the CPU, thereby executing a process for predicting deterioration of the denitration catalyst 104 of the denitration system 100 and a regeneration process for the deterioration. Further, the control unit 108 incorporates a clock (timer) for measuring a regeneration processing time of the denitration catalyst 104 described later. Processing in the control unit 108 will be described later.

The denitration catalyst 104 promotes the reaction between a reducing agent such as ammonia represented by the chemical reaction system shown in FIG. 2 and a nitride compound (NOx) in the exhaust gas. The exhaust gas contains nitrogen oxides (NOx) such as nitrogen monoxide (NO) and nitrogen dioxide (NO ₂ ), and ammonia generated by reaction with urea and water supplied from the reducing agent supply unit 106 It reacts and is decomposed into water and nitrogen by the reaction represented by the chemical formula (1).

When the exhaust gas contains sulfur oxides such as SO ₂ , the denitration catalyst 104 promotes the reaction represented by the chemical reaction system shown in FIG. Sulfur dioxide (SO ₂ ) contained in the exhaust gas reacts with ammonia generated by the reaction with urea and water supplied from the reducing agent supply unit 106, and reacts with the chemical formulas (3) and (4). Sulfur trioxide (SO ₃ ) and ammonium sulfate ((NH ₄ ) HSO ₄ ) are produced. The reaction represented by the chemical formula (4) is an equilibrium reaction in which the reaction from the left to the right easily proceeds as the temperature decreases, and the reaction from the right to the left easily proceeds as the temperature increases.

  FIG. 4 shows a system block diagram of the denitration system 100. As shown in FIG. 4, the denitration system 100 includes a gas flow meter 10, a gas thermometer 12, a nitrogen oxide concentration meter 14, 16, a sulfur oxide concentration meter 18, a urea amount injection controller 20, a urea injector 22, Generator 24, clutch 26, exhaust gas heating means 28, heater 30, load regulator 32 such as governor, display 34, alarm device 36, purge gas supply means 38, purge gas heating means 40, flow control valve 42, gas thermometer 44, An economizer 46 is included.

  The gas flow meter 10 measures the flow rate (superficial velocity) of the exhaust gas discharged from the combustion device 102 and the purge gas supplied from the purge gas supply unit 110 and outputs it to the control unit 108. Note that the superficial velocity (SV) of the denitration catalyst 104 can be represented by a ratio between the gas flow rate and the amount of the denitration catalyst 104. The gas thermometer 12 measures the temperature of the exhaust gas discharged from the combustion device 102 and the temperature of the purge gas supplied from the purge gas supply unit 110 and outputs the measured temperature to the control unit 108. As the gas flow meter 10 and the gas thermometer 12, an existing flow sensor or temperature sensor can be used. The gas flow meter 10 and the gas thermometer 12 are preferably provided in the gas passage 103 between the combustion device 102 and the denitration catalyst 104. The gas thermometer 44 measures the temperature of the gas discharged from the denitration catalyst 104 and outputs it to the control unit 108. An existing temperature sensor can be used for the gas thermometer 44. The gas thermometer 44 is preferably provided in the gas passage 103 on the outlet side of the denitration catalyst 104.

  The nitrogen oxide concentration meters 14 and 16 measure the concentration of nitrogen oxide (NOx) contained in the exhaust gas discharged from the combustion device 102 and output it to the control unit 108. As the nitrogen oxide concentration meters 14 and 16, a chemiluminescent NOx meter, a constant voltage electrolytic NOx meter, a general sensor using a zirconia solid electrolyte, or the like can be used. The nitrogen oxide concentration meter 14 is disposed in the gas passage 103 between the combustion device 102 and the denitration catalyst 104, and measures and outputs the concentration of nitrogen oxide in the exhaust gas before the denitration treatment on the inlet side of the denitration catalyst 104. To do. The nitrogen oxide concentration meter 16 is disposed on the outlet side of the denitration catalyst 104, and measures and outputs the concentration of nitrogen oxide in the exhaust gas after the denitration treatment on the outlet side of the denitration catalyst 104.

The sulfur oxide concentration meter 18 measures the concentration of sulfur oxide (SOx) contained in the exhaust gas discharged from the combustion device 102 and outputs it to the control unit 108. As the sulfur oxide (SOx), at least the concentration of SO ₂ is measured and output. As the sulfur oxide concentration meter 18, a sensor using a solid electrolyte or a sensor using an ultraviolet fluorescent method (UVF method) can be used. The sulfur oxide concentration meter 18 is disposed in the gas passage 103 between the combustion device 102 and the denitration catalyst 104, and measures and outputs the concentration of sulfur oxide in the exhaust gas before denitration treatment on the inlet side of the denitration catalyst 104. To do.

  The urea amount injection controller 20 and the urea injector 22 are elements constituting the reducing agent supply unit 106. The urea amount injection controller 20 is suitable for receiving nitrogen oxide (NOx) in the exhaust gas from the urea injector 22 to the denitration catalyst 104 via the gas passage 103 in response to a control signal from the control unit 108. Adjust the amount of urea and water. As described above, the urea injector 22 includes a urea tank, a pump, a urea valve, a compressor, an air valve, an injection nozzle, a pipe, and the like, and an amount of urea water controlled by the urea amount injection controller 20. Is injected into the gas passage 103. Information on the injection amount of the urea injector 22 is transmitted to the control unit 108 via the urea injection controller 20.

  The generator 24 receives the energy output from the combustion device 102 and generates power by rotating the rotor in a magnetic field formed by the stator. The electric energy obtained by the generator 24 may be used by the exhaust gas heating means 28, the heater 30, the purge gas supply means 38, and the purge gas heating means 40. The clutch 26 is used to open and close the clutch in response to a control signal from the control unit 108 and to switch between a state where the combustion device 102 is connected to the generator 24 and a state where it is not connected.

  The exhaust gas heating means 28 includes a reheating burner and an electric reheater. The exhaust gas heating means 28 is provided for heating the exhaust gas flowing through the gas passage 103 in response to a control signal from the control unit 108. The reheating burner mixes fuel by diffusing into the gas and burns it at a high temperature to raise the temperature of the exhaust gas. The electric reheater raises the temperature of exhaust gas by energizing a resistance heater or the like with electricity. When using an electric reheater, it is preferable to heat using the electricity output from the generator 24.

  The heater 30 includes means for heating the denitration catalyst 104. The heater 30 is provided to directly heat the denitration catalyst 104 or heat the exhaust gas flowing through the gas passage 103 in response to a control signal from the control unit 108. The heater 30 is preferably an electric induction heater, for example. The heater 30 is preferably heated using electricity output from the generator 24.

  The load regulator 32 such as the governor is a means for adjusting the load of the combustion device 102. The governor 32 adjusts the output load of the combustion device 102 according to the prediction result of the deterioration state of the denitration catalyst 104 in the control unit 108, and raises or lowers the temperature of the exhaust gas.

  The exhaust gas heating means 28, the heater 30 and the governor 32 may be provided with at least one of them. Further, the exhaust gas heating means 28 and the heater 30 may include at least one heating means such as a reheating burner, an electric reheater, and an electric induction heater.

  The display 34 is included in the control unit 108 and is used for presenting the control state of the deterioration regeneration system of the denitration catalyst 104 to the user. The alarm device 36 is included in the control unit 108 and issues a warning to the user in accordance with the deterioration of the denitration catalyst 104. Further, the deterioration information may be displayed on the display 34 for warning.

  The purge gas supply unit 38, the purge gas heating unit 40 and the flow rate control valve 42 constitute a purge gas supply unit 110. The purge gas supply means 38, the purge gas heating means 40, and the flow rate control valve 42 are used for the deterioration regeneration process of the denitration catalyst 104.

  The purge gas supply means 38 supplies the purge gas to the denitration catalyst 104 in the regeneration process of the denitration catalyst 104 performed while the combustion device 102 is stopped. The purge gas supply means 38 includes a device capable of compressing and feeding purge gas, such as a blower or a compressor. As shown in FIG. 1, the purge gas supply means 38 may include an auxiliary engine or a generator for driving a device such as a blower or a compressor.

  The purge gas supply means 38 is preferably diverted from means used for starting the combustion equipment 102 or means provided in the combustion equipment 102. For example, the starting compressor or auxiliary blower of the combustion device 102 can be used to supply the purge gas.

  The purge gas may be any gas that can purge the denitration catalyst 104 from the gas generated when the denitration catalyst 104 is regenerated. For example, air, nitrogen, a rare gas, or the like can be applied. Moreover, you may use the exhaust gas of the combustion apparatus 102 for a part or all as regeneration gas. It is particularly preferable to use air as the purge gas.

  The purge gas heating means 40 includes a heating burner and an electric heater. The purge gas heating means 40 is provided for heating the purge gas supplied from the purge gas supply means 38 in response to a temperature control signal from the control unit 108. The heating burner mixes the fuel by diffusing it into the gas and burns it at a high temperature to raise the temperature of the purge gas. The electric reheater raises the temperature of the purge gas by energizing a resistance heater or the like with electricity. In the case of using an electric reheater, it is preferable to perform heating using the electricity output from the generator included in the purge gas supply means 38 or the generator 24.

  The flow rate control valve 42 supplies and shuts off the purge gas from the purge gas supply means 38 to the denitration catalyst 104 and adjusts the flow rate (superficial velocity). When the regeneration process of the denitration catalyst 104 is started, the flow rate control valve 42 supplies the purge gas to the denitration catalyst 104 while controlling the flow rate of the purge gas according to the flow rate control signal from the control unit 108. Further, the flow rate control valve 42 is closed when the regeneration process of the denitration catalyst 104 is completed, and shuts off the purge gas supply path from the purge gas supply means 38 to the denitration catalyst 104.

  The economizer 46 includes a heat exchanger for using exhaust heat from the exhaust gas. A part of the exhaust pipe from the denitration catalyst 104 is passed through the housing of the economizer 46, and heat exchange with the exhaust heat of the exhaust gas flowing through the economizer 46 is performed. The heat exchange in the economizer 46 is controlled by the control unit 108. The control unit 108 is input with operation parameter settings such as start and stop of operation and measurement values of the state from the user through the operation operation panel, and adjusts the amount of exhaust gas flowing to the economizer 46 according to these input values. Thus, heat exchange with exhaust heat of exhaust gas is controlled.

In addition, by providing the economizer 46, decomposition products (NH ₃ , SO ₃ , H ₂ O) and acidic ammonium sulfate (NH ₄ HSO ₄ ) generated by the deterioration regeneration process of the denitration catalyst 104 can be recovered. Accordingly, adverse effects on the outside air can be suppressed. The ammonium sulfate adhering to the economizer 46 can be removed by washing with water, and the influence on the outside can be avoided by collecting the waste liquid after washing. In addition, since the characteristics may be deteriorated when the denitration catalyst 104 is wet, it is necessary to consider that moisture does not reach the denitration catalyst 104 when the economizer 46 is washed.

  Hereinafter, the regeneration process of the denitration catalyst 104 will be described with reference to the flowchart of FIG. The following processing is realized by executing a control program in the control unit 108. The regeneration process of the denitration catalyst 104 is performed while the combustion device 102 is stopped. For example, it is preferable to perform this while the combustion device 102 is stopped while the ship is anchored.

  In step S10, it is determined whether or not the regeneration process of the denitration catalyst 104 is started. If the reproduction process is started, the process proceeds to step S12. If not, the process returns to step S10 to make a regular determination.

  For example, the control unit 108 may start the regeneration process of the denitration catalyst 104 within a predetermined period when the combustion device 102 is stopped. It is preferable that the predetermined period is shorter than the period in which the temperature of the denitration catalyst 104 is 100 ° C. or less after the combustion device 102 is stopped. That is, if the regeneration process is started after the temperature of the denitration catalyst 104 becomes 100 ° C. or less, the time for increasing the temperature of the denitration catalyst 104 again becomes longer when the regeneration process is executed, which is necessary for the regeneration process. The time required for playback increases, and the power consumed by the playback process increases. More specifically, the predetermined period is preferably within one hour.

  Further, the regeneration process of the denitration catalyst 104 may be started when it is determined that the denitration catalyst 104 is degraded in a degradation evaluation process described later. As a result, the regeneration process can be performed in consideration of the actual deterioration state of the denitration catalyst 104.

  In step S12, supply of purge gas is started. The control unit 108 outputs a purge gas supply start signal to the purge gas supply unit 110 to operate the purge gas supply unit 38. Further, the control unit 108 outputs a flow rate control signal to the flow rate control valve 42 and sends a purge gas having a flow rate corresponding to the flow rate control valve 42 to the denitration catalyst 104. Further, the control unit 108 outputs a temperature control signal to the purge gas heating means 40 and heats the purge gas to a desired temperature in accordance with the temperature control signal. The temperature control of the purge gas may be performed by feedback control to the purge gas heating means 40 so that the temperature signal from the gas thermometer 44 becomes a desired temperature.

Thereby, the regeneration process of the denitration catalyst 104 is started. That is, by supplying a high temperature purge gas to the denitration catalyst 104, the temperature of the denitration catalyst 104 is increased, and the equilibrium equation (4) is caused to advance from the right side to the left side, and ammonium sulfate ((NH ₄ ) HSO ₄ ) is discharged as sulfur trioxide (SO ₃ ) gas. Sulfur trioxide (SO ₃ ) gas is effectively discharged from the denitration catalyst 104 by the purge gas.

  The temperature of the purge gas during the regeneration process is preferably set to 300 ° C. or more and 600 ° C. or less. If it is less than 300 ° C., the denitration catalyst 104 is not sufficiently heated, and the reaction of the equilibrium equation (4) does not easily proceed from the right side to the left side, and the regeneration process is not sufficiently performed or the regeneration process time becomes too long. Or Further, at 600 ° C. or higher, the titania contained in the denitration catalyst 104 is melted by heat, and thermal deterioration such as a reduction in the surface area of the denitration catalyst 104 becomes severe, resulting in a problem that the replacement frequency of the denitration catalyst 104 increases. From these viewpoints, the temperature of the purge gas during the regeneration process is more preferably in the range of 350 ° C. or more and 500 ° C. or less.

The purge gas flow rate (superficial velocity) is determined by the purge gas temperature and the regeneration processing time, as will be described later, but from the exhaust gas flow rate (superficial velocity) discharged when the combustion device 102 is operating. Even a small size is sufficient. Usually, in a marine diesel engine, the superficial velocity of exhaust gas during operation of the combustion device 102 is 10,000 to 25000 h ⁻¹ , but the superficial velocity required as the purge gas depends on the temperature of the purge gas and the regeneration processing time, It is about 1000 to 5000 h ^{−1 with} respect to the preferable purge gas temperature range and effective regeneration processing time range.

  Here, the temperature of the purge gas and the flow rate (superficial velocity) of the purge gas are set to preset values.

  In step S14, the temperature of the purge gas that has passed through the denitration catalyst 104 and reached the exhaust pipe is acquired. The control unit 108 acquires temperature data output from the gas thermometer 44.

  In step S16, the flow rate of the purge gas supplied to the denitration catalyst 104 is output. The control unit 108 acquires the flow rate (superficial velocity) data of the purge gas output from the gas flow meter 10.

  In step S18, the regeneration processing time of the denitration catalyst 104 corresponding to the purge gas temperature acquired in step S14 and the gas flow rate (superficial velocity) acquired in step S16 is calculated.

  FIG. 6 shows the relationship between the purge gas flow rate (superficial velocity) and the recovery of the activity K / K0 when the regeneration treatment is performed on the denitration catalyst 104 having the activity K / K0 degraded to 0.2. Show. Here, K is the activity of the actual denitration catalyst 104, K0 is the activity of the new denitration catalyst 104, and the activity K / K0 is the activity of the actual denitration catalyst 104 by the new denitration catalyst 104. This is a standardized value. FIG. 6 shows the degree of recovery of activity K / K0 when the regeneration processing time is limited to 2 hours.

As shown in FIG. 6, the regeneration processing time of the denitration catalyst 104 varies according to the purge gas temperature and the purge gas flow rate (superficial velocity). For example, when the purge gas temperature is 500 ° C., the regeneration process time of 2 hours is sufficient even if the purge gas flow rate (superficial velocity) is 1000 h ⁻¹ , but when the purge gas temperature is 400 ° C., In order to return the activity K / K0 to about 1 in the regeneration time of 2 hours, the flow rate of the purge gas (superficial velocity) needs to be 5000 h ⁻¹ or more.

  The control unit 108 controls the regeneration of the denitration catalyst 104 to the target value of the activity K / K0 in accordance with the set purge gas temperature (corresponding to the temperature of the denitration catalyst 104) and the purge gas flow rate (superficial velocity). Ask for time. For example, for each combination of the purge gas temperature and the purge gas flow rate (superficial velocity), the database stores the time until the denitration catalyst 104 is regenerated from the activity K / K0 before regeneration to the target value of the activity K / K0 after regeneration. Is registered in advance in the internal memory of the control unit 108, and after regeneration from the activity K / K0 before regeneration associated with the purge gas temperature and the purge gas flow rate (superficial velocity) acquired in steps S14 and S16. The time until reproduction to the target value of the activity K / K0 is extracted and set as the reproduction processing time. At this time, the regeneration processing time is set shorter as the purge gas temperature (corresponding to the temperature of the denitration catalyst 104) acquired in step S14 becomes higher.

  In step S20, it is determined whether or not to continue the reproduction process. The control unit 108 determines whether or not the reproduction processing time set in step S16 has elapsed since the time when the reproduction processing was started in step S12. If the reproduction processing time has elapsed, the control unit 108 ends the reproduction processing. The process of step S20 is repeated.

  In the present embodiment, the regeneration processing time is set based on the purge gas temperature and the purge gas flow rate (superficial velocity). However, the regeneration processing time is set in the control unit 108, and based on the regeneration processing time. The purge gas temperature and purge gas flow rate (superficial velocity) may be determined. For example, the target regeneration processing time is input to the control unit 108, and the purge gas that can be regenerated from the activity K / K0 before regeneration to the target value of the activity K / K0 after regeneration within the regeneration processing time. The minimum value of the temperature and the flow rate of the purge gas (superficial velocity) may be extracted from the database. At this time, by selecting the lowest value of the purge gas temperature that can achieve the target regeneration process time, the regeneration process can be performed so that the denitration catalyst 104 is not most thermally deteriorated.

  Moreover, it is good also as a structure which can select reproduction | regeneration processing time from several choices. For example, it may be possible to select a regeneration process taking one night (for example, 8 hours) and a rapid regeneration process of 2 hours according to the ship's operation schedule. In this case, the combination of the purge gas temperature and purge gas flow rate (superficial velocity) that satisfy each regeneration processing time is registered in advance in association with each regeneration processing time option, and corresponds to the selected regeneration processing time. The regeneration process may be performed using a combination of the temperature of the purge gas and the flow rate of the purge gas (superficial velocity).

  Of course, the purge gas flow rate (superficial velocity) may be determined based on the combination of the regeneration treatment time and the purge gas temperature, or the purge gas flow rate may be determined based on the combination of the regeneration treatment time and the purge gas flow rate (superficial velocity). It is good also as a structure which determines temperature.

  Furthermore, in this embodiment, the denitration catalyst 104 is indirectly heated using only the purge gas heating means 40, but the exhaust gas heating means 28 and the heater 30 may be diverted. When the heater 30 is used, the denitration catalyst 104 can be directly heated.

  In the present embodiment, it is preferable to raise the temperature of the purge gas or the temperature of the denitration catalyst 104 at a rate exceeding 60 ° C./hour. Particularly, it is suitable when niobium (Nb) is added to the denitration catalyst 104 as described above. As described above, it is possible to shorten the regeneration processing time by heating at a temperature rising rate exceeding 60 ° C./hour.

  In the present embodiment, the regeneration processing time is set based on the temperature of the purge gas. However, a temperature sensor is installed in the denitration catalyst 104 to acquire the temperature of the denitration catalyst 104, and the temperature of the denitration catalyst 104 is set. The playback processing time may be set based on this. In this case, in the regeneration process, the purge gas temperature may be read as the temperature of the denitration catalyst 104.

  As described above, in the denitration system 100 in the present embodiment, the conditions for the regeneration process of the denitration catalyst 104 are determined based on the purge gas temperature (temperature of the denitration catalyst 104), the purge gas flow rate (superficial velocity), and the regeneration process time. Control. Thereby, the regeneration process of the denitration catalyst 104 can be appropriately performed.

  Next, a modified example of the configuration of the denitration system 100 of the present embodiment will be described. As shown in FIG. 7, the denitration system 100 has a configuration in which a purge gas supply unit 38, a purge gas heating unit 40, and a flow rate control valve 42 dedicated to the regeneration process of the denitration catalyst 104 are provided after the combustion device 102. 7-12, the solid line arrow shows the flow of gas, and the broken line arrow shows the flow of control signal.

  As shown in FIG. 8, the first modification of the denitration system 100 has a configuration in which the purge gas heating means 40 is provided in the gas passage 103 through which the exhaust gas of the combustion device 102 passes. The purge gas heating means 40 may use the exhaust gas heating means 28, or may be provided separately from the exhaust gas heating means 28 exclusively for the purge gas.

  As shown in FIG. 9, the second modification of the denitration system 100 has a configuration in which the purge gas supply means 38 is diverted to the starter compressor 50 or the auxiliary blower 52 of the combustion device 102. The start-up compressor 50 is connected to the intake pipe of the combustion device 102, and when the combustion device 102 is started, the opening / closing valve 50a is opened and compressed air is sent into the cylinder of the combustion device 102 to start the movement of the piston. To be provided. The auxiliary blower 52 is connected to the supercharger of the combustion device 102, and when the combustion device 102 is started, the auxiliary blower 52 is opened by opening the bypass valves 52a and 52b and sending compressed air into the cylinder of the combustion device 102. It is provided to assist.

  In the second modification, the regeneration process is performed by supplying the purge gas using the starting compressor 50 or the auxiliary blower 52. When the starting compressor 50 is used, purge gas is supplied to the denitration catalyst 104 via the cylinder of the combustion device 102 that is stopped. When the auxiliary blower 52 is used, the purge gas is supplied to the denitration catalyst 104 through the cylinder and the supercharger of the stopped combustion device 102. The purge gas is heated by the purge gas heating means 40 provided in the gas passage 103.

  In the third modified example, as shown in FIG. 10, bypass paths 54 and 56 not passing through the combustion device 102 may be provided for supplying purge gas from the starting compressor 50 or the auxiliary blower 52. In this case, when the combustion device 102 is started, the bypass valves 54a and 56a are closed and the on-off valves 50a and 52c are opened to start the operation of the combustion device 102 as described above. When the denitration catalyst 104 is regenerated, the bypass valves 54a and 56a are started. Is opened and the on-off valves 50 a and 52 c are closed to supply purge gas to the denitration catalyst 104.

  Further, in the fourth modification of the denitration system 100, as shown in FIG. 11, the purge gas heating means 40 and the denitration catalyst 104 are arranged in the upflow in order from the bottom in the direction of gravity. With such an arrangement, the density of the purge gas thermally expanded by heating with the purge gas heating means 40 is reduced, and the purge gas is supplied to the denitration catalyst 104 via the flow rate control valve 42 by natural drafting force.

  Furthermore, as shown in FIG. 12, the fifth modification of the denitration system 100 may include a heater 30 that directly heats the denitration catalyst 104 in addition to the fourth modification. In such a configuration, the denitration catalyst 104 can be directly heated by the heater 30 in addition to the purge gas heating by the purge gas heating means 40.

  In addition, it is good also as a structure which combined suitably the component shown in the said FIGS. 7-12, and good also as a structure omitted suitably.

  Further, the regeneration process of the denitration catalyst 104 may be started based on the prediction of the deterioration of the denitration catalyst 104 shown in the flowchart of FIG. The following processing is realized by executing a control program in the control unit 108.

  In step S30, the exhaust gas flow rate, temperature, nitrogen oxide concentration, and sulfur oxide concentration are measured. The CPU of the control unit 108 controls the exhaust gas flow rate, the exhaust gas temperature, and the inlet side from the gas flow meter 10, the gas thermometer 12, the nitrogen oxide concentration meters 14 and 16, and the sulfur oxide concentration meter 18 connected via an external interface. The measured values of the nitrogen oxide concentration, the nitrogen oxide concentration on the outlet side, and the sulfur oxide concentration on the inlet side are obtained.

  In step S32, the reducing agent (urea) and moisture injection amount from the reducing agent supply unit 106 that has processed the rotational speed, torque, supply air pressure, etc. of the combustion device 102, the combustion device load value of the load regulator 32 such as the governor. Is acquired. The CPU of the control unit 108 acquires respective characteristic values from the combustion device 102, the reducing agent supply unit 106, and the governor 32 that are connected via an external interface.

In step S34, the concentration of sulfur trioxide (SO ₃ ) and the concentration of ammonia (NH ₃ ) are calculated using the chemical reaction model. As shown in FIG. 14, the gas passage 103 in the denitration catalyst 104 is divided into a plurality of regions A0 to An (n is an integer of 1 or more) along the flow direction of the exhaust gas, and each region A1 from the inlet of the denitration catalyst 104. the time until the exhaust gas reaches the boundary of the ~An as t1 to tn (the time interval tn-t (a n-1) = Δt), sulfur trioxide (SO ₃₎ in each area A0~An and Obtain the concentration of ammonia (NH ₃ ). It is assumed that the concentrations of sulfur trioxide (SO ₃ ) and ammonia (NH ₃ ) in each region A0 to An are approximately equal to the concentration at the inlet of each region A0 to An.

The reaction rate of sulfur trioxide (SO ₃ ) and ammonia (NH ₃ ) can be expressed by a first-order reaction equation as shown in reaction rate equations (5) and (6).

Here, -ΔC _SO2 is the concentration decrease amount of sulfur dioxide (SO ₂ ), ΔC _SO3 is the concentration increase amount of sulfur trioxide (SO ₃ ) (= -ΔC _SO2 : from the chemical formula (3)), and C _SO2 is sulfur dioxide. (SO ₂ ) concentration, −ΔC _NH3 is ammonia (NH ₃ ) concentration decrease amount, C _NH3 is ammonia concentration, K _SO2 and K _NH3 are reaction rate coefficients, F _SO2 (t, An), F _NH3 (t , An) is the activity of the denitration catalyst 104 in the region An at time t (0 ≦ F _SO2 (t, An), F _NH3 (t, An) ≦ 1). F _NH3 (t, An) is equal to F _SO2 (t, An), and their initial value is 1.

The reaction rate coefficient K _NH3 in the reaction rate equation of ammonia (NH ₃ ) at the boundary of each region can be obtained from the denitration rate of nitrogen oxides (NOx). For example, if the denitration rate of nitrogen oxide (NOx) is η _NOX %, the volume ratio α (= NH ₃ / NOx [ppm / ppm) of ammonia (NH ₃ ) concentration and nitrogen oxide (NOx) concentration on the catalyst inlet side. ppm]) and 0 ≦ α ≦ 1, the reaction rate equation of nitrogen oxide (NOx) is expressed by the primary reaction equation as in the chemical equation (6). Thus, the reaction rate coefficient K _NH3 can be obtained by substituting the time tn.

From the chemical formula (1) of the denitration reaction, the reaction rate coefficient K _NH3 of ammonia (NH ₃ ) can be _calculated from the reaction rate coefficient K _NOx by determining the equivalent ratio of the reaction between nitrogen oxide (NOx) and ammonia (NH ₃ ). Can be sought. In the denitration treatment of exhaust gas, the reaction between nitrogen monoxide (NO) and ammonia (NH ₃ ) is mainly performed in the chemical formula (1), so the reaction between nitrogen dioxide (NO ₂ ) and ammonia (NH ₃ ). May be ignored approximately. In this way, the reaction rate coefficient K _NH3 of ammonia (NH ₃ ) can be obtained from the measured values of the nitrogen oxide (NO x) concentration at the inlet and outlet of the denitration catalyst 104.

On the other hand, the reaction rate coefficient K _SO2 of the reaction in which sulfur trioxide (SO ₃ ) is generated from sulfur dioxide (SO ₂ ) is obtained by an experiment using simulated exhaust gas. FIG. 15 shows the relationship between the oxidation rate of sulfur dioxide (SO ₂ ) and temperature when a simulated exhaust gas is passed through a fixed bed small-flow catalyst test apparatus (catalyst filling amount: 40 to 50 cc) as a test apparatus. FIG. 16 shows the relationship between the amount of sulfur tetroxide (SO ₄ ) adhering to the catalyst and the activity of the NOx removal catalyst F _SO2 (t, An), F _NH3 (t, An) = K _SO2 / K _SO2 0. Indicates. Here, K _SO2 0 is the reaction rate coefficient K _SO2 of the denitration catalyst which has not deteriorated at the beginning of the experiment. In the case of a vanadium-based denitration catalyst, the SO ₂ oxidation activity and the active metal of the denitration catalyst are common vanadium, so F _SO2 (t, An), F _NH3 (t, An) = K _NH3 / K _NH3 0 or The activity may be calculated from K _NOX / K _NOX 0.

As the catalyst, a vanadium (V) -tungsten (W) / titanium dioxide (TiO ₂ ) honeycomb type low temperature denitration catalyst was used. In the simulation test, a mixed gas of 800 ppm of sulfur dioxide (SO ₂ ), 13% of oxygen (O ₂ ), 1500 ppm of nitric oxide (NO), and 10% by weight of water was flowed in a nitrogen balance, and 3% as a reducing agent. Urea water was hydrolyzed to ammonia (NH ₃ ) with an evaporator at 400 ° C., and about 1500 ppm in terms of ammonia (NH ₃ ) was supplied upstream of the denitration catalyst. The superficial velocity (SV) of the experimental denitration catalyst was 25000 h ⁻¹ . The reaction temperature was changed in the range of 200 ° C to 400 ° C.

In such simulated exhaust gas experiments, dehumidification was performed using an NDIR sulfur dioxide (SO ₂ ) concentration meter according to the literature (Carlo Orsenigo, Ind. Eng. Chem. Res, 1998, vol. 37, pp. 2350-2359). sulfur dioxide (SO ₂₎ concentration after treatment were measured, the oxidation rate of sulfur dioxide (SO ₂₎ was inlet and sulfur dioxide (SO ₂₎ in the outlet concentration reduction rate of the catalyst. The amount of sulfur tetroxide (SO ₄ ) adhering to the catalyst was quantified by extracting the deteriorated catalyst and using a water extraction method or ion chromatography analysis.

From the relationship thus obtained, the reaction rate coefficient K _SO2 of the reaction in which sulfur trioxide (SO ₃ ) is produced from sulfur dioxide (SO ₂ ) at each temperature, and sulfur tetraoxide (SO ₂ ) attached to the catalyst. ₄ ) and the activity of the NOx removal catalyst 104 F _SO2 (t, An), F _NH3 (t, An) = K _SO2 / K _SO2 0 can be obtained.

Here, as one of the features of the denitration catalyst degradation prediction method and degradation countermeasure method of the present embodiment, as shown in FIG. 15, the reaction temperature rises and sulfur dioxide (SO ₂ ) increases up to 400 ° C. The point which uses the relationship where the oxidation rate of this falls is mentioned. Conventionally, the oxidation rate of sulfur dioxide (SO ₂ ) was thought to increase as the reaction temperature increased, but in the exhaust gas in the actual denitration reaction, the reaction temperature increased and the oxidation rate of sulfur dioxide (SO ₂ ) decreased. It has become a relationship.

Such a tendency is not limited to the vanadium (V) -tungsten (W) / titanium dioxide (TiO ₂ ) -type honeycomb-type low-temperature denitration catalyst, and the same tendency is observed in other denitration catalysts such as vanadium. It is thought that shows. However, in the temperature range exceeding 400 ° C., it is conceivable that the oxidation rate of sulfur dioxide (SO ₂ ) increases as the reaction temperature increases.

The reaction rate coefficient K _SO2 , the reaction rate coefficient K _NH3, and the activity of the NOx removal catalyst 104 F _SO2 (t, An), F _NH3 (t, An) = K _SO2 / K _SO2 0 were obtained. By applying the equations (6) and (7), the concentrations of sulfur trioxide (SO ₃ ) and ammonia (NH ₃ ) in each region A0 to An at time T are obtained.

In step S36, the amount deposited as ammonium sulfate ((NH ₄ ) HSO ₄ ) in the sulfur trioxide (SO ₃ ) in each region A0 to An calculated in step S34 is calculated. Here, the amount precipitated as ammonium sulfate ((NH ₄ ) HSO ₄ ) is calculated using the above-described equilibrium formula (8). Here, P _SO3 is a partial pressure of sulfur trioxide (SO ₃ ), P _NH3 is a partial pressure of ammonia (NH ₃ ), R is a gas constant, and T is a temperature.

Here, P _SO3 is a partial pressure of sulfur trioxide (SO ₃ ), P _NH3 is a partial pressure of ammonia (NH ₃ ), R is a gas constant, and T is a temperature. The equilibrium formula (8) is disclosed in literature (S Matsuda et.al, Ind. Eng. Prod. Res., Dev. 1982, vol. 21, pp. 48-52).

In the equilibrium equation (8), the product of partial pressure (concentration) of sulfur trioxide (SO ₃ ) and ammonia (NH ₃ ) is expressed as a function of temperature. Therefore, by converting the ammonia (NH ₃ ) concentration obtained in step S34 into partial pressure and substituting it into the equilibrium equation (8) together with the exhaust gas temperature Tmp, sulfur trioxide (SO 2) that can exist as a gas in that state. ₃ ) Partial pressure can be obtained. Then, the partial pressure of sulfur trioxide (SO ₃ ) that can exist as a gas is converted into a concentration, and is subtracted from the generated concentration of sulfur trioxide (SO ₃ ) obtained in step S 34, thereby obtaining ammonium sulfate ((NH ₄ ) HSO. _{As 4} ), the amount deposited on the surface of the denitration catalyst 104 can be calculated. In addition, the equilibrium calculation of ammonium sulfate may be a proxy for calculation using literature equilibrium data of chemical formula (4) or chemical equilibrium calculation software.

Furthermore, the amount of ammonium sulfate ((NH ₄ ) HSO ₄ ) deposited on the surface of the denitration catalyst 104 is cumulatively added to the amount of ammonium sulfate ((NH ₄ ) HSO ₄ ) that has already been deposited by time T. The precipitation accumulation value of ammonium sulfate ((NH ₄ ) HSO ₄ ) in ˜An can be calculated.

In step S38, the activity of the denitration catalyst 104 in each of the regions A0 to An is obtained based on the precipitation accumulation value of ammonium sulfate ((NH ₄ ) HSO ₄ ) in each of the regions A0 to An obtained in step S36.

As shown in FIG. 16, the amount of sulfur tetroxide (SO ₄ ) adhering to the catalyst by the experiment with the simulated gas and the activity of the NOx removal catalyst 104 F _SO2 (t, An), F _NH3 (t, An) = K _SO2 / K _SO2 0 is obtained in advance, and the activity F _SO2 (t, An), F _NH3 (t, An) of the denitration catalyst 104 is determined from the total precipitation amount of ammonium sulfate ((NH ₄ ) HSO ₄ ) in each region A0 to An. = K _SO2 / K _SO2 0 is obtained.

In step S40, is the regeneration process of the denitration catalyst 104 performed based on the activities F _SO2 (t, An), F _NH3 (t, An) = K _SO2 / K _SO2 0 of the denitration catalyst 104 obtained in step S38? Determine whether or not.

  The regeneration process can be performed, for example, when the activity value of the denitration catalyst 104 in each of the regions A0 to An falls below a predetermined reference threshold value. For example, it may be performed when the average value of the activity of the denitration catalyst 104 in each of the regions A0 to An falls below a predetermined reference threshold. However, the treatment is not limited to these, and any treatment based on the activity of the denitration catalyst 104 may be used.

  When performing the deterioration countermeasure process, the process proceeds to the process after step S12 in the flowchart of the reproduction process shown in FIG. If not, the process moves to step S30 to perform the deterioration prediction process at the next time T.

  Further, in the deterioration countermeasure process, for example, information indicating that the activity of the denitration catalyst 104 exceeds the reference threshold is displayed on the display 34 and a warning is given to the user (an administrator of the combustion device 102). Also good. Moreover, it is good also as giving a warning with respect to a user (administrator of the combustion apparatus 102) by emitting a sound and light from the alarm device 36.

  In this case, the user can manually execute a process of increasing the temperature Tmp of the exhaust gas, or stop the combustion device 102 and start the regeneration process of the denitration catalyst 104.

Hereinafter, the above process will be described more specifically. At the start of the denitration process, various data are acquired in steps S30 to S32. In step S34, the activities F _SO2 (t, An), F _NH3 (t, An) = K of the denitration catalyst 104 in each region A0 to An. _SO2 / K _SO2 0 is 1 (no deterioration), and the concentrations of sulfur trioxide (SO ₃ ) and ammonia (NH ₃ ) at the outlet side boundary of each region A0 to An due to the exhaust gas flowing from the inlet of the denitration catalyst 104 are obtained. It is done. That is, the concentrations of sulfur trioxide (SO ₃ ) and ammonia (NH ₃ ) at the time Δt passing through the region A 0 at time T = 0 are determined based on the activities F _SO2 (t, An), F _NH3 ( t, An) = K _SO2 / K _SO2 0 is set to 1, and the reaction rate equations (5) and (6) are changed to the reaction rate coefficients K _SO2 , K _NH3 , sulfur disulfide (SO ₂ ) and ammonia (SO ₂ ) in exhaust gas at the catalyst inlet. It can be obtained by substituting the concentration of NH ₃ ). Since the exhaust gas flowing in from the inlet of the denitration catalyst 104 at time T = 0 reaches the boundary between the regions A1 to An at times t1, t2,... Tn, the time Δt that passes through the region A1 at time t1. The concentrations of sulfur trioxide (SO ₃ ) and ammonia (NH ₃ ) at the time are determined by the activity F _SO2 (t, An), F _NH3 (t, An) = K _SO2 / K _SO2 0 in the region A1 at time t1. Is obtained by substituting the reaction rate coefficients K _SO2 and K _NH3 and the concentrations of sulfur disulfide (SO ₂ ) and ammonia (NH ₃ ) reaching the region A1 into the reaction rate equations (5) and (6). it can. Similarly, sulfur trioxide in the time Δt to pass at the time t2 concentration of sulfur trioxide (SO ₃₎ and ammonia (NH ₃₎ at time Δt which passes through the area A2, the area A3 at time t3 (SO ₃₎ And the concentration of ammonia (NH ₃ ): the concentrations of sulfur trioxide (SO ₃ ) and ammonia (NH ₃ ) at the time Δt passing through the region An at time tn can be calculated.

Next, in step S36, sulfur trioxide in the region A0 at time T = 0 (SO ₃₎ and ammonia concentration (NH _3), sulfur trioxide in the region A1 at time t1 (SO ₃₎ and ammonia ( From the concentration of NH ₃ ) and the temperature (Tmp) of the reaction (exhaust gas), the amount of ammonium sulfate ((NH ₄ ) HSO ₄ ) deposited in region A0 at time T = 0, and ammonium sulfate ((( The amount of precipitation of NH ₄ ) HSO ₄ ) is determined. Of the calculated amount of precipitation in the region A0 until time T = 0 ammonium sulfate ((NH ₄₎ HSO ₄₎ precipitation amount of the cumulative value, ammonium sulfate in the region A1 at time _{t1 ((NH 4) HSO 4} ) It is set as the initial value of the accumulated value ... of the deposited amount.

In step S38, the activity F _SO2 (t, An), F _NH3 of the denitration catalyst 104 in the region A0 is calculated from the accumulated value of the amount of ammonium sulfate ((NH ₄ ) HSO ₄ ) deposited in each region A0 to An at time T = 0. (T, An) = K _SO2 / K _SO2 0 is obtained. Since the exhaust gas has not yet reached the other regions A1 to An, the activity of the NOx removal catalyst 104 F _SO2 (t, An), F _NH3 (t, An) = K _SO2 / K _SO2 0 remains 1 Become.

In step S40, regeneration against deterioration is performed based on the activities F _SO2 (t, An), F _NH3 (t, An) = K _SO2 / K _SO2 0 of the denitration catalyst 104 in each region A0 to An determined in step S38. It is determined whether or not the process is to be performed. If the reproduction process is not to be performed, the process returns to step S30.

In Steps S30 to S32, various data are acquired again, and in Step S34, the concentrations of sulfur trioxide (SO ₃ ) and ammonia (NH ₃ ) are obtained from the exhaust gas flowing from the inlet of the denitration catalyst 104 at time T = Δt. . Here, for the region A0, the concentration is calculated using the activities F _SO2 (t, An), F _NH3 (t, An) = K _SO2 / K _SO2 0 newly obtained in step S38, and other regions are obtained. the concentration of 1 sulfur trioxide as (Lossless) (SO ₃₎ and ammonia (NH ₃₎ are determined for Al-An. That is, the concentrations of sulfur trioxide (SO ₃ ) and ammonia (NH ₃ ) at the time Δt passing through the region A0 at the time T = Δt are the values in the region A0 obtained by the processing at the time T = 0 in step S38. Activity values F _SO2 (t, An), F _NH3 (t, An) = K _SO2 / K _SO2 0 are used, and the reaction rate equations K _SO2 , K _NH3 and the reaction rate equations (5) and (6) It can be determined by substituting the concentrations of sulfur disulfide (SO ₂ ) and ammonia (NH ₃ ) in the exhaust gas at the catalyst inlet. Since the exhaust gas flowing in from the inlet of the denitration catalyst 104 at time T = Δt reaches the boundary between the regions A1 to An after time t1, t2,... Tn, the time Δt that passes through the region A1 at time Δt + t1. The concentrations of sulfur trioxide (SO ₃ ) and ammonia (NH ₃ ) at the time indicated by the activity F _SO2 (t, An), F _NH3 (t, An) = K _SO2 / K _SO2 0 in region A1 at time Δt + t1 Is obtained by substituting the reaction rate coefficients K _SO2 and K _NH3 and the concentrations of sulfur disulfide (SO ₂ ) and ammonia (NH ₃ ) reaching the region A1 into the reaction rate equations (5) and (6). it can. Similarly, sulfur trioxide (SO ₃₎ in the time Delta] t to pass through the region A2 at the time Delta] t + t2 and ammonia concentration (NH _3), sulfur trioxide in the time Delta] t to pass through the area A3 at time Δt + t3 (SO ₃₎ And the concentration of ammonia (NH ₃ ): the concentrations of sulfur trioxide (SO ₃ ) and ammonia (NH ₃ ) at the time Δt passing through the region An at time Δt + tn can be calculated.

Next, in step S36, the concentration of sulfur trioxide in the region A0 at time T = Δt (SO ₃₎ and ammonia (NH _3), sulfur trioxide (SO ₃₎ in the region A1 at time Delta] t + t1 and ammonia ( From the concentration of NH ₃ ) and the temperature (Tmp) of the reaction (exhaust gas), the amount of ammonium sulfate ((NH ₄ ) HSO ₄ ) deposited in the region A0 at the time T = Δt, the ammonium sulfate in the region A1 at the time Δt + t1 (( The amount of precipitation of NH ₄ ) HSO ₄ ) is determined. A cumulative value of the precipitation amount of ammonium sulfate ((NH ₄ ) HSO ₄ ) in the region A0 from the calculated precipitation amount to time T = Δt is obtained. That is, for the region A0, the total amount of precipitation of ammonium sulfate ((NH ₄ ) HSO ₄ ) at the times T = 0 and T = Δt is a cumulative value, and for the region A1, the time T obtained by the processing for the time T = 0. = Amount of precipitation of ammonium sulfate ((NH ₄ ) HSO ₄ ) at t1 (= Δt) is a cumulative value. Than the partial pressure of sulfur trioxide that may be present as a gas for region A2~An (SO _3), below the product concentration of sulfur trioxide (SO ₃₎ which was oxidized with a catalyst in each region A2～An is generated, ammonium sulfate The amount of precipitation of ((NH ₄ ) HSO ₄ ) is zero.

In step S38, the activity F _SO2 (t, An) of the denitration catalyst 104 in the regions A0 and A1 is calculated from the accumulated value of the precipitation amount of ammonium sulfate ((NH ₄ ) HSO ₄ ) in each region A0 and A1 at time T = Δt. F _NH3 (t, An) = K _SO2 / K _SO2 0 is obtained. Still 0, so the amount of ammonium sulfate precipitation in other areas A2～An, activity F _SO2 denitration catalyst 104 (t, An), F NH3 (t, An) = K SO2 / K SO2 0 remains at 1 .

In step S40, the denitration catalyst 104 is calculated based on the activities F _SO2 (t, An), F _NH3 (t, An) = K _SO2 / K _SO2 0 of the denitration catalyst 104 in each region A0 to An determined in step S38. Whether or not to perform the reproduction process is determined. If the reproduction process is not performed, the process returns to step S30.

By repeating such processing, it is possible to execute deterioration prediction processing of the denitration catalyst 104 and start regeneration processing of the denitration catalyst 104 based on the prediction result. However, the deterioration prediction process is not limited to the above, and in the exhaust gas process in which ammonia substance is added to the exhaust gas from the combustion device 102 and nitrogen oxide is decomposed by the denitration catalyst 104, the denitration catalyst by sulfur oxides. What is necessary is just to predict the deterioration of 104 based on at least the relationship between the temperature Tmp and the oxidation rate of the sulfur oxide. In particular, the relationship between the temperature Tmp and the oxidation rate of the sulfur oxide is preferably a relationship in which the oxidation rate decreases as the temperature increases, but the temperature at which the oxidation rate of sulfur dioxide (SO ₂ ) increases as the temperature increases. It is also possible to use for the catalyst of the area or the said characteristic.

  In addition, when a temporal change in the exhaust gas discharged from the combustion device 102 can be predicted, the expected value of the change in the properties of the exhaust gas (exhaust gas flow rate, temperature, nitrogen oxide concentration, sulfur oxide concentration, etc.) Based on this, it is possible to predict future deterioration of the denitration catalyst 104.

For example, when the properties of the exhaust gas discharged from the combustion device 102 do not change with time, the properties of the exhaust gas (the exhaust gas flow rate, temperature, nitrogen oxide concentration, and sulfur oxidation) acquired first in step S30 in the deterioration prediction process The amount of ammonium sulfate ((NH ₄ ) HSO ₄ ) deposited on the denitration catalyst 104 in the future based on the concentration of the product, and the time when the activity of the denitration catalyst 104 exceeds a predetermined reference threshold And the predicted time may be presented to the user.

  The above embodiment can be applied to the treatment of exhaust gas from marine diesel engines, but is not limited to this, and can also be applied to other mobile objects such as railway vehicles and automobiles. The present invention can also be applied to an engine (such as a direct injection type Otto engine) that performs intermittent combustion other than a diesel engine. Furthermore, the present invention can be applied to general combustion equipment such as garbage incinerators and thermal power generation facilities.

  12 Gas thermometer, 14, 16 Nitrogen oxide concentration meter, 18 Sulfur oxide concentration meter, 28 Exhaust gas heating means, 30 Heating heater, 32 Governor and other load regulator, 38 Purge gas supply means, 40 Purge gas heating means, 42 Flow rate control Valve, 44 Gas thermometer, 100 Denitration system, 102 Combustion equipment, 103 Gas passage, 104 Denitration catalyst, 106 Reductant supply unit, 108 Control unit.

Claims (14)

In exhaust gas treatment that adds ammonia-based substances to exhaust gas from combustion equipment and decomposes nitrogen oxides with a denitration catalyst,
When the regeneration treatment for the deterioration due to sulfur oxides of the denitration catalyst is performed by blowing air by the blowing means and heating by the heating means at the time of stopping the operation of the combustion equipment, the regeneration space velocity of the denitration catalyst due to the blowing and the heating A denitration catalyst deterioration regeneration method, characterized in that the regeneration process is controlled based on a regeneration temperature of the denitration catalyst and a regeneration process time for the denitration catalyst.   2. The method according to claim 1, wherein the regeneration processing time is controlled to become shorter as the regeneration temperature becomes higher.   The method for regenerating deterioration of a denitration catalyst according to claim 1 or 2, wherein the regeneration temperature is in a range of 300 ° C or higher and 600 ° C or lower.   The denitration catalyst deterioration regeneration method according to any one of claims 1 to 3, wherein the heating means heats the denitration catalyst at a temperature rising rate exceeding 60 ° C / h.   The method for regenerating deterioration of a denitration catalyst according to any one of claims 1 to 4, wherein the denitration catalyst contains niobium (Nb). Combustion equipment,
An exhaust gas path for exhausting exhaust gas from the combustion device;
A denitration catalyst provided in the exhaust gas path;
Ammonia-based material addition means for adding ammonia-based material to the exhaust gas provided in the exhaust gas path between the combustion device and the denitration catalyst;
Air blowing means for blowing air to the denitration catalyst;
Heating means for heating the denitration catalyst;
Based on the regeneration space-time speed of the denitration catalyst by the air blow, the regeneration temperature of the denitration catalyst by the heating, and the regeneration treatment time for the denitration catalyst, the regeneration treatment for the denitration catalyst when the operation of the combustion equipment is stopped Playback control means for controlling
A denitration catalyst deterioration regeneration system characterized by comprising:   The denitration catalyst deterioration regeneration system according to claim 6, wherein the regeneration space-time speed is smaller than an operation space-time speed due to exhaust gas during operation of the combustion equipment.   8. The denitration catalyst according to claim 6, wherein the blowing unit arranges the denitration catalyst above the heating unit to generate a natural draft force by heating by the heating unit and blows air. Deterioration reproduction system.   The deterioration regeneration system for a denitration catalyst according to any one of claims 6 to 8, wherein the combustion device is a diesel engine.   The denitration catalyst deterioration regeneration system according to claim 9, wherein the blowing means is a means used for starting the diesel engine or a means installed in the diesel engine.   11. The denitration catalyst deterioration regeneration system according to claim 6, wherein the denitration catalyst contains niobium (Nb).   12. The deterioration regeneration of the denitration catalyst according to claim 6, further comprising a deterioration prediction unit of the catalyst, wherein the regeneration process is performed based on a predicted value of the deterioration prediction unit. system.   The deterioration regeneration system for a denitration catalyst according to any one of claims 6 to 12, wherein the regeneration control means can set a plurality of regeneration treatment times for the denitration catalyst.   The deterioration regeneration system for a denitration catalyst according to any one of claims 6 to 13, wherein the regeneration treatment for the denitration catalyst is started within one hour after the operation of the combustion equipment is stopped.