JP2017008772A - Denitrification and desulfurization device and internal combustion engine for land and marine industry using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a single denitrification catalyst to simultaneously perform both denitrification and desulfurization of exhaust gas from an internal combustion engine which burns heavy oil.SOLUTION: A denitrification and desulfurization device comprises: a supercharger 104 which supplies air to an internal combustion engine 102 using energy of exhaust gas; reducing agent supply means 12 which injects a reducing agent to treat nitrogen oxide; and a denitrification catalyst 10 which reacts the nitrogen oxide with the reducing agent. The denitrification catalyst 10: is arranged in a passage at a downstream side of the supercharger 104; keeps a temperature of the exhaust gas passing through the denitrification catalyst 10 within a temperature range not less than 150°C and not more than 280°C; and simultaneously performs denitrification of the exhaust gas and absorption of acidic ammonium sulfate produced by the reaction of sulfur oxide with the reducing agent onto the denitrification catalyst 10 under a condition that a space velocity obtained by diving an amount of the exhaust gas passing through the denitrification catalyst 10 by a volume of the denitrification catalyst 10 is kept in a range not less than 500hand not more than 2700h.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a denitration desulfurization apparatus and an internal combustion engine for land and marine industries using the same.

  In an internal combustion engine such as a diesel engine that burns heavy oil, a reduction in sulfur oxide (SOx) is required in addition to a reduction in nitrogen oxide (NOx) contained in exhaust gas discharged from the engine. In order to reduce nitrogen oxide (NOx) and sulfur oxide (SOx) at the same time, reduction device for nitrogen oxide (NOx) such as selective catalytic reduction device (SCR) and reduction of sulfur oxide (SOx) such as scrubber A configuration is adopted in which the devices are respectively installed in the exhaust gas flow paths.

  In the exhaust gas treatment system of a boiler, after removing nitrogen oxides (NOx) contained in exhaust gas with a denitration device, sulfur oxides (SOx) are absorbed with a limestone gypsum desulfurization device. A configuration to be removed is disclosed (Patent Document 1). In addition, a configuration is disclosed in which nitrogen oxide (NOx) is removed by a denitration reactor after performing a treatment for removing sulfur oxide (SOx) contained in exhaust gas by a denitration reactor (Patent Document). 2).

  On the other hand, in the treatment of exhaust gas from internal combustion engines and oil refining plants, a low-temperature denitration process in which denitration treatment is performed using a reducing agent in a temperature range of 320 ° C. or less using a denitration catalyst, and accumulated in the denitration catalyst in this process A method of repeating a catalyst regeneration step in which a sulfur-containing compound that is a poisoning substance is removed and regenerated is disclosed (Patent Document 3).

JP 2002-179411 A JP-A-11-165043 JP 2005-87815 A

  By the way, a denitration apparatus such as an SCR has a relatively simple structure and is easy to maintain. On the other hand, a desulfurization apparatus such as a scrubber has a complicated structure and complicated maintenance. Therefore, when a desulfurization apparatus is provided in addition to the denitration apparatus, the maintenance of the exhaust gas treatment system as a whole becomes complicated, and the cost increases.

  The present invention makes it possible to simultaneously perform denitration treatment and desulfurization treatment of exhaust gas of an internal combustion engine that burns heavy oil using a single denitration catalyst.

A denitration desulfurization apparatus according to claim 1 of the present invention is a denitration desulfurization apparatus that simultaneously processes nitrogen oxides and sulfur oxides of exhaust gas of an internal combustion engine that burns heavy oil, and uses the energy of the exhaust gas to A supercharger for supplying air to the internal combustion engine, a reducing agent supply means for injecting a reducing agent for treating the nitrogen oxide, and a denitration catalyst for reacting the nitrogen oxide and the reducing agent, The denitration catalyst is disposed in a path downstream from the supercharger, and the exhaust gas passing through the denitration catalyst has a temperature range of 150 ° C. or higher and 280 ° C. or lower, and the exhaust gas passing through the denitration catalyst. the space velocity of the quantity of gas divided by the volume of the denitration catalyst under conditions in the range of 500h ^-1 or 2700H ^-1 or less, in the reaction of the denitration of the exhaust gas at the same time as the sulfur oxides the reducing agent Jill acidic ammonium sulfate is adsorbed to the denitration catalyst. The denitration desulfurization apparatus can be an internal combustion engine for land and marine industry that is mounted on an internal combustion engine for land and marine industry and uses the denitration desulfurization apparatus.

  The exhaust gas temperature changing means for changing the temperature of the exhaust gas passing through the denitration catalyst is provided, and the temperature of the exhaust gas passing through the denitration catalyst is changed to a temperature range of 150 ° C. or higher and 280 ° C. or lower. Is preferred.

  Further, the exhaust gas temperature changing means changes the temperature of the exhaust gas to a temperature range of 150 ° C. or higher and lower than 225 ° C. at the beginning of operation, and then changes the temperature of the exhaust gas to 225 ° C. or higher and 280 ° C. or lower. Is preferred.

  The internal combustion engine is preferably a 4-stroke diesel engine. The internal combustion engine is preferably a two-stroke diesel engine.

  The denitration catalyst is provided divided into a plurality of stages, and the number of cells per unit cross-sectional area of the denitration catalyst in at least one stage is the number of cells per unit cross-sectional area of the denitration catalyst in another stage. Is preferably different from

  In addition, a plurality of the denitration catalysts arranged in parallel, and a switching valve that switches a gas that flows to the denitration catalyst to the path that passes through each of the denitration catalysts, and the operation of the denitration catalyst by switching the switching valve The exhaust gas is allowed to flow through the denitration catalyst, and when the denitration catalyst is regenerated, a high-temperature gas having a temperature equal to or higher than the regeneration temperature is caused to flow through the denitration catalyst. Is preferably switched.

  In addition, it is preferable that a poisoning substance removing device for removing a poisoning substance of the denitration catalyst is provided downstream of the denitration catalyst in the path.

  Also, a nitrogen oxide concentration measuring means for measuring the concentration of the nitrogen oxide downstream of the denitration catalyst, a sulfur oxide concentration measuring means for measuring the concentration of the sulfur oxide downstream of the denitration catalyst, and the denitration catalyst It is preferable that at least one of differential pressure measuring means for measuring the differential pressure of the exhaust gas before and after the operation is switched, and the operation and regeneration of the denitration catalyst are switched based on at least one of the measurement results by the provided measuring means. It is.

The denitration desulfurization apparatus according to claim 1 of the present invention is a denitration desulfurization apparatus that simultaneously processes nitrogen oxides and sulfur oxides of exhaust gas of an internal combustion engine that burns heavy oil, using the energy of the exhaust gas. A supercharger for supplying air to the internal combustion engine, a reducing agent supply means for injecting a reducing agent for treating the nitrogen oxide, and a denitration catalyst for reacting the nitrogen oxide and the reducing agent. The denitration catalyst is disposed in a path downstream from the supercharger, and the temperature of the exhaust gas passing through the denitration catalyst is set to a temperature range of 150 ° C. or higher and 280 ° C. or lower and passes through the denitration catalyst. under conditions that the amount of the exhaust gas to a volume by dividing the space velocity 500h ^-1 or more 2700H ^-1 or less in the range of the denitration catalyst, when the denitration of the exhaust gas at the same time as the sulfur oxides of the reducing agent By acidic ammonium sulfate can be adsorbed onto the denitration catalyst caused by the response can be performed simultaneously denitration and desulfurization processing required by the combustion of heavy oil by one of the denitration catalyst. Thereby, a denitration desulfurization apparatus having a simple structure and suppressing maintenance costs can be provided.

When using the denitration desulfurization apparatus in an internal combustion engine for land舶産industry, since the surrounding space, it can be increased unlike the automobile or the like, the range of space velocity 500h ^-1 or 2700H ^-1 or less by increasing the volume of the denitration catalyst Can be easily done.

  In addition, exhaust gas temperature changing means for changing the temperature of the exhaust gas passing through the denitration catalyst is provided, and the temperature of the exhaust gas passing through the denitration catalyst is changed to a temperature range of 150 ° C. or higher and 280 ° C. or lower. The sulfur oxide (SOx) in the exhaust gas can be effectively adsorbed and removed by the denitration catalyst as acidic ammonium sulfate.

  Further, the exhaust gas temperature changing means changes the temperature of the exhaust gas to a temperature range of 150 ° C. or higher and lower than 225 ° C. at the beginning of operation, and then changes the temperature of the exhaust gas to 225 ° C. or higher and 280 ° C. or lower. Thus, acidic ammonium sulfate can be more effectively adsorbed in the initial stage of the exhaust gas treatment in the denitration catalyst, and soot (soot) can be more effectively removed using the acidic ammonium sulfate as a binder. Thereafter, by returning to the normal exhaust gas processing temperature range, sulfur oxide (SOx) and soot (soot) in the exhaust gas can be stably removed.

  Further, since the internal combustion engine is a four-stroke diesel engine, the exhaust gas temperature changing means effectively changes the temperature of the exhaust gas passing through the denitration catalyst to a temperature range of 150 ° C. or higher and 280 ° C. or lower. In addition, sulfur oxide (SOx) in the exhaust gas can be removed. Further, since the internal combustion engine is a two-stroke diesel engine, the temperature of the exhaust gas passing through the denitration catalyst by the exhaust gas temperature changing means or not depends on the temperature range of 150 ° C. or higher and 280 ° C. or lower. In particular, sulfur oxide (SOx) in the exhaust gas can be removed.

  The denitration catalyst is provided divided into a plurality of stages, and the number of cells per unit cross-sectional area of the denitration catalyst in at least one stage is the number of cells per unit cross-sectional area of the denitration catalyst in another stage. The soot (soot) contained in the exhaust gas can be effectively removed.

  In addition, a plurality of the denitration catalysts arranged in parallel, and a switching valve that switches a gas that flows to the denitration catalyst to the path that passes through each of the denitration catalysts, and the operation of the denitration catalyst by switching the switching valve The exhaust gas is allowed to flow through the denitration catalyst, and when the denitration catalyst is regenerated, a high-temperature gas having a temperature equal to or higher than the regeneration temperature is caused to flow through the denitration catalyst. By switching the above, denitration and desulfurization treatment of the exhaust gas can be performed continuously while switching a plurality of the denitration catalysts.

  Further, by providing a poisoning substance removing device that removes a poisoning substance of the denitration catalyst on the downstream side of the denitration catalyst in the path, the poisoning substance released when the denitration catalyst is regenerated is removed by the poisoning substance. It can be recovered and removed by a removal device.

  Also, a nitrogen oxide concentration measuring means for measuring the concentration of the nitrogen oxide downstream of the denitration catalyst, a sulfur oxide concentration measuring means for measuring the concentration of the sulfur oxide downstream of the denitration catalyst, and the denitration catalyst Comprising at least one of differential pressure measuring means for measuring the differential pressure of the exhaust gas before and after, and switching between operation and regeneration of the denitration catalyst based on at least one of measurement results by the provided measuring means, Based on the measurement result, operation and regeneration can be switched according to the deterioration state of the denitration catalyst.

It is a figure which shows the structure of the denitration desulfurization apparatus in embodiment of this invention. It is a figure which shows the poisoning substance removal means in embodiment of this invention. It is a figure which shows the structure of the denitration desulfurization apparatus in embodiment of this invention. It is a figure which shows the structure of the denitration catalyst in embodiment of this invention. It is a figure which shows the structure of the denitration desulfurization apparatus in embodiment of this invention. It is a figure which shows the structure of the denitration desulfurization apparatus in embodiment of this invention. It is a figure which shows the performance deterioration with time of the denitration catalyst in embodiment of this invention.

  As shown in FIG. 1, a denitration desulfurization apparatus 100 according to an embodiment of the present invention includes a denitration catalyst 10 (10a, 10b), a reducing agent supply means 12, an air supply means 14, a heater 16, and a poisonous substance removal means 18. Consists of including.

  The denitration desulfurization apparatus 100 is disposed in a flow path of exhaust gas discharged from the internal combustion engine 102 that burns heavy oil, and removes nitrogen oxide (NOx) and sulfur oxide (SOx) contained in the exhaust gas. The internal combustion engine 102 is provided with a supercharger 104 for supplying air to the internal combustion engine 102 using the energy of the exhaust gas, and a denitration desulfurization device 100 is provided in a downstream path of the supercharger 104.

The denitration catalyst 10 is a catalyst in a selective catalyst reduction device (SCR). The denitration catalyst 10 removes nitrogen oxides (NOx) contained in the exhaust gas discharged from the internal combustion engine 102. The denitration catalyst 10 is preferably a titanium / vanadium catalyst. For example, the denitration catalyst 10 is a titanium oxide TiO ₂ -based catalyst containing vanadium (V), molybdenum (Mo), or tungsten (W) as an active component. By supplying ammonia as a reducing agent to the denitration catalyst 10, it is reacted with nitrogen oxides (NOx), and decomposed into water and nitrogen as in chemical formula (1). Also, a method is adopted in which urea is injected into the exhaust gas flow path and ammonia is supplied to the catalyst by decomposing urea as in chemical formula (2).

<Chemical formula (1)>
4NO + 4NH ₃ + O ₂ → 4N ₂ + 6H ₂ O
6NO ₂ + 8NH ₃ → 7N ₂ + 12H ₂ O

<Chemical formula (2)>
(NH ₂ ) ₂ CO + H ₂ O → 2NH ₃ + CO ₂

  The denitration catalyst 10 is filled in a casing connected to the exhaust gas path. When the denitration catalyst 10 is a titanium / vanadium catalyst, it is preferable to have a structure in which a plurality of cells, which are flat plates or thin tubes of catalyst, are bundled in order to increase the reaction area. For example, the denitration catalyst 10 preferably has a honeycomb structure.

The reducing agent supply means 12 can include a urea tank, a pump, a urea valve, a compressor, and an air valve. The reducing agent supply means 12 is provided to supply urea (urea water) and air to the upstream path from the denitration catalyst 10 via the injection nozzle. For example, urea (urea water ((NH ₂ ) ₂ CO + H ₂ O)) is injected into the exhaust passage 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 10. A configuration is preferable. However, the reducing agent is not limited to urea (urea water), and for example, ammonia may be used directly.

By the way, in the case of heavy oil containing sulfur oxides (SOx) such as sulfur dioxide (SO ₂ ) in the exhaust gas discharged from the internal combustion engine 102, as shown in chemical formulas (3) and (4), reduction A poisoning substance such as acidic ammonium sulfate (ammonium hydrogen sulfate) is generated by the reaction with the reducing agent supplied from the agent supply means 12.

<Chemical formula (3)>
SO ₂ + (1/2) O ₂ → SO ₃

<Chemical formula (4)>
NH ₃ + SO ₃ + H ₂ O ← → NH ₄ HSO ₄

  In the denitration desulfurization apparatus 100, the produced poisonous substance such as acidic ammonium sulfate is adsorbed and recovered by the denitration catalyst 10, and sulfur oxide (SOx) is removed from the exhaust gas discharged from the internal combustion engine 102. That is, adsorption of poisoning substances (primary poisoning) is actively used for removing sulfur oxides (SOx), and in the denitration catalyst 10, nitrogen oxides (NOx) and sulfur oxides (SOx) are removed at the same time. To do.

Here, in order to sufficiently remove sulfur oxide (SOx) from the exhaust gas, it is necessary to provide the denitration catalyst 10 having a sufficient volume with respect to the amount of exhaust gas passing through the denitration catalyst 10. Therefore, a space velocity obtained by dividing the amount of exhaust gas that passes through the denitration catalyst 10 by volume of the denitration catalyst 10 2700H ^-1 or less, more preferably preferably set to 1350H ^-1 or less. By applying the denitration catalyst 10 that satisfies such conditions, sulfur oxide (SOx) contained in the exhaust gas can be sufficiently removed. In particular, it is possible to remove sulfur oxide (SOx) from exhaust gas when burning heavy oil having a sulfur component of 0.1% or more, and further 0.5% or more. On the other hand, considering the volume that can be realistically implemented, the space velocity obtained by dividing the amount of exhaust gas that passes through the denitration catalyst 10 by volume of the denitration catalyst 10 500h ^-1 or more, more preferably preferably set to 1000h ^-1 or It is.

When the denitration desulfurization apparatus 100 is used for an internal combustion engine for the land and marine industry, the surrounding space can be increased unlike an automobile or the like. Therefore, the volume of the denitration catalyst 10 is increased and the space velocity is 500 h ⁻¹ or more and 2700 h ⁻ A range of ¹ or less can be easily achieved. Further, in order to reduce the frequency of switching between a first state and a second state, which will be described later, it is preferable to set the space velocity to 1350h ⁻¹ or less. For example, in the case of marine vessels, the space velocity can be stored without hindrance. above in 500h ^-1 or more, more preferably preferably set to 1000h ^-1 or more.

  Thus, nitrogen oxide (NOx) and sulfur oxide (SOx) are removed. In order to regenerate the denitration catalyst 10 by removing poisoning substances adsorbed on the denitration catalyst 10, the air supply means 14 and the heater 16 are used. And poisoning substance removing means 18 are provided.

  The air supply means 14 includes an air supply device such as a compressor, and supplies air to the denitration catalyst 10. The heater 16 heats the air supplied by the air supply means 14 to a temperature equal to or higher than the regeneration temperature of the denitration catalyst 10 and supplies it to the denitration catalyst 10. Specifically, the heater 16 is preferably capable of heating air to 350 ° C. or higher. In the present embodiment, air is supplied for the regeneration of the denitration catalyst 10, but another gas may be supplied. By supplying air heated to the regeneration temperature or higher to the denitration catalyst 10 in this way, poisonous substances adsorbed on the denitration catalyst 10 can be vaporized and desorbed from the denitration catalyst 10.

  The poisoning substance removing unit 18 is a unit for resorbing and collecting the poisoning substance desorbed from the denitration catalyst 10. For example, as shown in FIG. 2, the poisoning substance removing means 18 includes a hollow wedge-shaped member 18a, a scraping plate 18b provided with a notch into which the wedge-shaped member 18a is inserted, and a wall surface 18c into which the wedge-shaped member 18a is inserted. They can be combined. A cooling liquid such as seawater is circulated through the wedge-shaped member 18a, and the poisonous substance gas evaporated and desorbed from the denitration catalyst 10 contacts the surface of the wedge-shaped member 18a to be solidified and adsorbed. Thereafter, the scraping plate 18b is urged in a direction in which it is pressed against the surface of the wedge-shaped member 18a (downward in the front view of FIG. 2B), and the wedge-shaped member 18a is pulled out of the scraping plate 18b, whereby the wedge-shaped member 18a The poisoning substance adhering to the surface is scraped off by the scraping plate 18b and collected in a poisoning substance storage tank or the like.

  In addition, it is preferable that the denitration desulfurization apparatus 100 has a configuration in which two denitration catalysts 10a and 10b are provided in parallel so that the other can be regenerated while the denitration process and the desulfurization process are performed.

  In the present embodiment, switching valves 20a to 20e are provided, a denitration catalyst 10a performs a denitration and desulfurization process of exhaust gas from the internal combustion engine 102, and a denitration catalyst 10b performs a regeneration process; The denitration catalyst 10b is configured to switch between a second state in which denitration and desulfurization processing of exhaust gas from the internal combustion engine 102 is performed and regeneration processing is performed in the denitration catalyst 10a.

  In the first state, the switching valve 20a is switched so that the exhaust gas from the internal combustion engine 102 flows into the denitration catalyst 10a and does not flow into the denitration catalyst 10b. Further, the switching valve 20b is switched so that the gas supplied from the air supply means 14 flows into the denitration catalyst 10b and does not flow into the denitration catalyst 10a. Further, the switching valve 20c is switched so that the reducing agent is injected into the exhaust gas flowing into the denitration catalyst 10a and the reducing agent is not injected into the gas flowing into the denitration catalyst 10b. Further, the switching valve 20d is switched so that the gas discharged from the denitration catalyst 10b flows into the poisoning substance removing unit 18 and the exhaust gas discharged from the denitration catalyst 10a does not flow into the poisoning substance removing unit 18. Further, the switching valve 20e is switched so that the exhaust gas discharged from the denitration catalyst 10a flows into the chimney and the gas discharged from the denitration catalyst 10b does not flow into the chimney.

  In the second state, the switching valves 20a to 20e are switched so as to be in the opposite state. Further, when switching between the first state and the second state, the switching valves 20a to 20e are switched in cooperation so that the exhaust gas from the internal combustion engine 102 does not stagnate so as not to hinder the operation.

  By adopting such a configuration, it is possible to treat the exhaust gas with the other denitration catalyst while regenerating one denitration catalyst. Therefore, the removal of nitrogen oxides (NOx) and sulfur oxides (SOx) from the exhaust gas can be performed continuously without interruption.

  In order to deposit acidic ammonium sulfate in chemical formula (4) in the denitration catalyst 10, the temperature of the exhaust gas when passing through the denitration catalyst 10 is 150 ° C. or higher and 280 ° C. or lower, more preferably 200 ° C. or higher and 250 ° C. or lower. It is preferable to do. That is, from the viewpoint of the acid dew point, the lower limit of the exhaust gas temperature range is preferably 150 ° C. or higher, more preferably 200 ° C. or higher. Further, from the viewpoint of efficiently adsorbing acidic ammonium sulfate on the denitration catalyst 10, the upper limit of the exhaust gas temperature range is preferably 280 ° C. or less, more preferably 250 ° C. or less.

  Here, when the internal combustion engine 102 is a two-stroke diesel engine, the temperature of the exhaust gas after passing through the supercharger 104 is generally 200 ° C. or higher and 280 ° C. or lower. Therefore, in this case, the exhaust gas discharged from the internal combustion engine 102 via the supercharger 104 may be directly introduced into the denitration desulfurization apparatus 100.

  On the other hand, when the internal combustion engine 102 is a four-stroke diesel engine, the temperature of the exhaust gas after passing through the supercharger 104 is generally 300 ° C. or higher and 450 ° C. or lower. In this case, as shown in FIG. 3, it is preferable to provide an exhaust gas temperature changing means 106 in a path between the supercharger 104 and the denitration catalyst 10. The exhaust gas temperature changing means 106 is preferably a heat exchanger (exhaust heat recovery device) that recovers heat from the exhaust gas, for example. The temperature of the exhaust gas may be lowered to 150 ° C. or higher and 280 ° C. or lower by recovering the heat of the exhaust gas via the exhaust gas temperature changing means 106 and then introduced into the denitration catalyst 10.

  Further, the denitration catalyst 10 may be configured to further remove soot. As shown in the schematic diagram of FIG. 4, the denitration catalyst 10 is configured by combining a plurality of cylindrical cells 22 arranged vertically and horizontally. Therefore, soot (soot) is removed from the exhaust gas by using the cylindrical cell 22 as a filter.

  At this time, as shown in FIG. 4, each of the denitration catalysts 10 is divided into a plurality of stages, and the number of cells per unit cross-sectional area of at least one stage differs from the number of cells per unit cross-sectional area of other stages. Is preferable. For example, the denitration catalyst 10 is divided into two stages, and the number of cells 22a per unit cross-sectional area in the front stage is made larger than the number of cells 22b per unit cross-sectional area in the rear stage. In such a configuration, soot is removed positively at the front stage, and the rear stage is less likely to be clogged with soot. For this reason, it becomes possible to perform denitration and desulfurization efficiently in the latter stage. Conversely, the number of cells per unit cross-sectional area in the previous stage may be smaller than the number of cells per unit cross-sectional area in the rear stage. In such a configuration, it is possible to remove a large soot at the front stage, a smaller soot at the rear stage, and evenly remove the soot at each stage. For this reason, clogging due to adhesion of soot (soot) in the previous stage is reduced, and the pressure loss of the exhaust gas due to the denitration catalyst 10 is reduced.

  Further, when the exhaust gas temperature changing means 106 is provided, when the exhaust gas is processed by the NOx removal catalyst 10, the temperature of the exhaust gas is changed to 150 ° C. or higher and lower than 225 ° C. at the initial stage of operation, and then the exhaust gas temperature is changed. It is preferable to change the temperature to 225 ° C. or higher and 280 ° C. or lower. As a result, acidic ammonium sulfate is easily adsorbed to the denitration catalyst 10 in the initial stage of operation, and the adsorbed acidic ammonium sulfate serves as a binder and easily captures soot. After soot (soot) can be easily captured, both acidic ammonium sulfate and soot can be stably captured by setting the temperature within a normal temperature range.

  When soot (soot) is removed by the denitration catalyst 10, it is preferable to provide an air supply means 30 for soot blow and a soot storage tank 32 as shown in FIG. The air supply means 30 supplies air for blowing soot (soot) to the denitration catalyst 10 (10a, 10b). The air supply means 30 is preferably configured to blow air from the downstream side to the upstream side of the denitration catalyst 10. The soot storage tank 32 collects and stores the soot removed from the denitration catalyst 10 by the air supply means 30.

  In the configuration of FIG. 5, a switching valve 20f is provided to soot blow the catalyst to be regenerated among the denitration catalysts 10a and 10b. The soot blow is preferably performed before the regeneration treatment of the denitration catalyst 10a or the denitration catalyst 10b.

  Note that switching between operation and regeneration of the denitration catalyst 10 is preferably performed in accordance with the characteristics of the exhaust gas after treatment and the state of the denitration desulfurization apparatus 100. Specifically, as shown in FIG. 6, a nitrogen oxide concentration measurement sensor 40 that measures the concentration of nitrogen oxide (NOx) in the exhaust gas downstream of the denitration catalyst 10, and in the exhaust gas downstream of the denitration catalyst 10. At least one of a sulfur oxide concentration measurement sensor 42 that measures the concentration of sulfur oxide (SOx) of the exhaust gas and a differential pressure measurement sensor 44 that measures the differential pressure of exhaust gas before and after the denitration catalyst 10 is provided. It is preferable to switch operation and regeneration of the denitration catalyst 10 based on at least one of the results measured by the means.

  For example, when the concentration of nitrogen oxide (NOx) in the exhaust gas measured by the nitrogen oxide concentration measurement sensor 40 exceeds a predetermined reference value, the denitration catalyst 10 currently used for the processing deteriorates. As a result, the reproduction process is performed. When a plurality of denitration catalysts 10 are provided as shown in FIG. 6, the denitration catalyst 10 used for exhaust gas treatment is switched to regeneration, and the regenerated denitration catalyst 10 is switched to exhaust gas treatment.

  Further, for example, when the concentration of sulfur oxide (SOx) in the exhaust gas measured by the sulfur oxide concentration measuring sensor 42 exceeds a predetermined reference value, the denitration catalyst 10 currently used for the processing is used. Reproduction processing is performed on the assumption that it has deteriorated. When a plurality of denitration catalysts 10 are provided as shown in FIG. 6, the denitration catalyst 10 used for exhaust gas treatment is switched to regeneration, and the regenerated denitration catalyst 10 is switched to exhaust gas treatment.

  Further, for example, when the differential pressure of the denitration catalyst 10 currently used for processing the exhaust gas measured by the differential pressure measurement sensor 44 exceeds a predetermined reference value, the denitration catalyst currently used for the processing. Reproduction processing is performed on the assumption that 10 has deteriorated. When a plurality of denitration catalysts 10 are provided as shown in FIG. 6, the denitration catalyst 10 used for exhaust gas treatment is switched to regeneration, and the regenerated denitration catalyst 10 is switched to exhaust gas treatment.

  At this time, as shown in FIG. 7, in the general denitration catalyst 10, the deterioration proceeds in the order of the denitration performance, the desulfurization performance, and the differential pressure maintenance performance with respect to the time used for the treatment of the exhaust gas. The deterioration of the denitration catalyst 10 may be detected based on the priority order of the measurement results of the measurement sensor 40, the sulfur oxide concentration measurement sensor 42, and the differential pressure measurement sensor 44. Further, at least one of the nitrogen oxide concentration measurement sensor 40, the sulfur oxide concentration measurement sensor 42, and the differential pressure measurement sensor 44 is provided, and the deterioration of the denitration catalyst 10 is detected based on the measurement result of the provided sensor. I can do it. Further, the deterioration of the denitration catalyst 10 may be detected by appropriately combining the measurement results measured by the nitrogen oxide concentration measurement sensor 40, the sulfur oxide concentration measurement sensor 42, and the differential pressure measurement sensor 44.

  The present invention can be applied to the denitration and desulfurization treatment of internal combustion engines that burn various heavy oils including diesel engines. That is, an internal combustion engine for the land and marine industry equipped with the denitration desulfurization apparatus of the present invention can be obtained.

  10 (10a, 10b) Denitration catalyst, 12 Reducing agent supply means, 14 Air supply means, 16 Heater, 18 Toxic substance removal means, 18a Wedge member, 18b Scraping plate, 20a to 20f Switching valve, 22 (22a, 22b) ) Cell, 30 air supply means, 32 soot storage tank, 40 nitrogen oxide concentration measurement sensor, 42 sulfur oxide concentration measurement sensor, 44 differential pressure measurement sensor, 100 denitration desulfurization apparatus, 102 internal combustion engine, 104 supercharger, 106 Exhaust gas temperature changing means.

Claims (10)

A denitration desulfurization apparatus that simultaneously processes nitrogen oxides and sulfur oxides of exhaust gas of an internal combustion engine that burns heavy oil,
A supercharger for supplying air to the internal combustion engine using energy of the exhaust gas;
Reducing agent supply means for injecting a reducing agent for treating the nitrogen oxides;
A denitration catalyst for reacting the nitrogen oxides and the reducing agent;
The denitration catalyst is disposed in a path downstream from the supercharger,
The temperature of the exhaust gas passing through the denitration catalyst is set to a temperature range of 150 ° C. or more and 280 ° C. or less, and the space velocity obtained by dividing the amount of the exhaust gas passing through the denitration catalyst by the volume of the denitration catalyst is 500 h ^−. A denitration desulfurization apparatus, wherein the exhaust gas is denitrated under the condition of ¹ or more and 2700 h- ¹ or less, and at the same time, acidic ammonium sulfate produced by the reaction of the sulfur oxide and the reducing agent is adsorbed to the denitration catalyst. . The denitration desulfurization apparatus according to claim 1,
An exhaust gas temperature changing means for changing the temperature of the exhaust gas passing through the denitration catalyst,
A denitration desulfurization apparatus, wherein the temperature of the exhaust gas passing through the denitration catalyst is changed to a temperature range of 150 ° C or higher and 280 ° C or lower. A denitration desulfurization apparatus according to claim 2,
The exhaust gas temperature changing means changes the temperature of the exhaust gas to a temperature range of 150 ° C. or higher and lower than 225 ° C. in the initial stage of operation, and then changes the temperature of the exhaust gas to 225 ° C. or higher and 280 ° C. or lower. Denitration desulfurization equipment. A denitration desulfurization apparatus according to claim 2 or 3,
The denitration desulfurization apparatus, wherein the internal combustion engine is a four-stroke diesel engine. The denitration desulfurization apparatus according to any one of claims 1 to 3,
The denitration desulfurization apparatus, wherein the internal combustion engine is a two-stroke diesel engine. A denitration desulfurization apparatus according to any one of claims 1 to 5,
The denitration catalyst is provided divided into a plurality of stages,
A denitration desulfurization apparatus, wherein the number of cells per unit cross-sectional area of the denitration catalyst of at least one stage is different from the number of cells per unit cross-sectional area of the denitration catalyst of another stage. A denitration desulfurization apparatus according to any one of claims 1 to 6,
A plurality of the denitration catalysts arranged in parallel;
A switching valve for switching a gas flowing through the denitration catalyst in the path passing through each of the denitration catalysts;
By switching the switching valve, the exhaust gas is caused to flow through the denitration catalyst during operation of the denitration catalyst, and a high-temperature gas having a temperature equal to or higher than the regeneration temperature is caused to flow through the denitration catalyst during regeneration. A denitration desulfurization apparatus that switches between the operation and regeneration of the plurality of denitration catalysts during the operation. A denitration desulfurization apparatus according to claim 7,
A denitration desulfurization apparatus comprising a poisoning substance removing device that removes a poisoning substance of the denitration catalyst on the downstream side of the denitration catalyst in the path. A denitration desulfurization apparatus according to claim 7 or 8,
Nitrogen oxide concentration measuring means for measuring the concentration of nitrogen oxide downstream of the denitration catalyst, sulfur oxide concentration measuring means for measuring the concentration of sulfur oxide downstream of the denitration catalyst, and before and after the denitration catalyst At least one of differential pressure measuring means for measuring the differential pressure of the exhaust gas, and switching between operation and regeneration of the denitration catalyst based on at least one of the measurement results by the provided measuring means. Denitration desulfurization equipment.   An internal combustion engine for land and marine industries using the denitration desulfurization apparatus, wherein the denitration desulfurization apparatus according to any one of claims 1 to 9 is mounted on an internal combustion engine for land and marine industries.

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