JP2015222163A - Denitration equipment and catalytic exchange method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide denitration equipment capable of efficiently removing nitrogen oxides for a longer period of time, or a catalytic exchange method.SOLUTION: Denitration equipment includes: an exhaust gas passage 40f through which exhaust gas flows; a flow-straightening and denitration catalyst layer 80 that is installed in the exhaust gas passage 40f; and at least one of denitration catalyst layers 82, 84 and 86 that are arranged on the flow-direction downstream side of the exhaust gas with respect to the flow-straightening and denitration catalyst layer 80 of the exhaust gas passage 40f. The flow-straightening and denitration catalyst layer 80 is shorter in length in the flow direction of the exhaust gas than the denitration catalyst layers 82, 84 and 86.

Description

  The present invention relates to a denitration facility that removes nitrogen oxides contained in exhaust gas and a catalyst replacement method that replaces the catalyst of the denitration facility.

  As a combustor that burns coal as fuel, there is a boiler that pulverizes fuel and burns it as pulverized coal. A conventional pulverized coal fired boiler is supplied with a mixture of pulverized coal (fuel) obtained by pulverizing coal and air for transportation (primary air), and also supplied with high-temperature secondary air. By blowing secondary air into the furnace, a flame is formed and combustion gas can be generated. This furnace has a flue connected to the upper part, and a superheater, a reheater, a economizer, etc. are provided in the flue to recover the heat of the exhaust gas. Water can be heated to produce steam. Further, this flue is connected to an exhaust gas passage, a denitration facility, an electrostatic precipitator, a desulfurization device and the like are provided in the exhaust gas passage, and a chimney is provided at the downstream end.

  In the denitration facility, a denitration catalyst that promotes the reduction reaction of nitrogen oxides is stacked (see Patent Document 1). Examples of the denitration catalyst include a plate catalyst in which plates are laminated in a direction orthogonal to the direction in which air passes, and a honeycomb type catalyst in which holes are opened in a honeycomb shape. In addition, as a denitration catalyst used in a denitration facility, there is a denitration catalyst in which a coating layer is provided on an end surface on the side into which a catalyst gas flows (see Patent Document 2).

JP 2008-126146 A JP 2000-237600 A

  Here, when coal is burned as fuel, combustion ash, unburned components, and popcorn ash (bulky ash) in which the burned ash and unburned components are solidified are mixed in the exhaust gas. When popcorn ash reaches the denitration facility in a state where it is contained in the exhaust gas, it may be deposited on the denitration catalyst of the denitration facility. When popcorn ash is deposited on the denitration catalyst, the exhaust gas flowing in that portion is reduced or eliminated, so that the nitrogen oxide removal performance is reduced, and maintenance such as replacement is required.

  Further, if the exhaust gas contains various solids such as ash, the denitration catalyst may be worn. On the other hand, as in Patent Document 2, by protecting a part of the inflow side, the wear resistance can be improved, but the denitration performance is lowered.

  The present invention solves the above-described problems, and an object thereof is to provide a denitration facility and a catalyst replacement method that can efficiently remove nitrogen oxide for a longer period of time.

  In order to achieve the above object, the present invention provides a denitration facility, an exhaust gas passage through which exhaust gas can flow, a rectification and denitration catalyst layer installed in the exhaust gas passage, and the rectification and denitration catalyst layer of the exhaust gas passage And at least one denitration catalyst layer disposed downstream of the exhaust gas flow direction, and the rectification and denitration catalyst layer has a shorter length in the exhaust gas flow direction than the denitration catalyst layer It is characterized by that.

  In the rectification and denitration catalyst layer, the hydraulic diameter of the catalyst opening is preferably larger than the hydraulic diameter of the catalyst opening of the denitration catalyst layer.

  The rectification and denitration catalyst layer preferably has a hydraulic diameter of the catalyst opening of 8 mm or more.

  The rectification and denitration catalyst layer is preferably a plate catalyst, and the denitration catalyst layer is preferably a honeycomb catalyst.

  In order to achieve the above object, the present invention provides a denitration facility, an exhaust gas passage through which exhaust gas can flow, a rectification layer installed in the exhaust gas passage, and a flow direction of exhaust gas relative to the rectification layer of the exhaust gas passage And at least two denitration catalyst layers disposed on the downstream side, wherein the at least two denitration catalyst layers are plate catalyst in the most upstream denitration catalyst layer in the flow direction of the exhaust gas, The denitration catalyst layer on the most downstream side in the exhaust gas flow direction is a honeycomb catalyst, and the denitration catalyst layers of all the plate catalysts are arranged upstream of the honeycomb catalyst denitration catalyst layer in the exhaust gas flow direction. It is characterized by.

  In order to achieve the above object, the present invention provides an exhaust gas passage through which exhaust gas flows, a rectifying layer installed in the exhaust gas passage, and at least disposed in the exhaust gas flow direction downstream of the rectifying layer of the exhaust gas passage. A denitration catalyst layer, and a plate-like catalyst is disposed in a region where the flow rate is relatively slow with respect to the average flow rate of the exhaust gas flowing through the denitration catalyst layer. The honeycomb catalyst is arranged in a region where the flow velocity is high.

  In order to achieve the above object, the present invention provides a denitration facility, an exhaust gas passage through which exhaust gas can flow, a rectification layer installed in the exhaust gas passage, and a flow direction of exhaust gas relative to the rectification layer of the exhaust gas passage At least one denitration catalyst layer disposed on the downstream side, wherein the denitration catalyst layer is formed by laminating a plate catalyst and a honeycomb catalyst, and the plate catalyst is a flow direction of the exhaust gas of the honeycomb catalyst. The end face on the plate-like catalyst side is close to the honeycomb catalyst.

  In the exhaust gas passage, it is preferable that the exhaust gas flows from the upper side to the lower side in the vertical direction from the viewpoint of suppressing catalyst wear and increase in pressure loss due to foreign matter.

  In order to achieve the above object, the present invention is a method for replacing a catalyst in a denitration facility comprising a rectification layer and a denitration catalyst layer disposed downstream of the rectification layer in the flow direction of exhaust gas, Determining whether the rectifying layer has a catalytic function, and, if the rectifying layer does not have a catalytic function, replacing the rectifying layer with a rectifying and denitrating catalyst layer having a denitrating catalyst function; It is characterized by having.

  The rectification and denitration catalyst layer preferably has a hydraulic diameter of the catalyst opening of 8 mm or more.

  The rectification and denitration catalyst layer is preferably a plate catalyst.

  In order to achieve the above object, the present invention provides a method for replacing a catalyst in a denitration facility comprising a rectification layer and at least two denitration catalyst layers disposed downstream of the rectification layer in the exhaust gas flow direction. And a step of identifying a denitration catalyst layer to be replaced, and a step of replacing the denitration catalyst layer to be replaced with a plate catalyst when there is no honeycomb catalyst upstream in the flow direction of the exhaust gas. It is characterized by.

  In order to achieve the above object, the present invention provides a method for replacing a catalyst in a denitrification facility comprising a rectification layer and at least one denitration catalyst layer disposed downstream of the rectification layer in the exhaust gas flow direction. The step of identifying the denitration catalyst layer to be replaced and the denitration catalyst layer to be replaced are arranged such that a plate-like catalyst is arranged in a relatively slow flow rate region and a honeycomb catalyst is arranged in a relatively high flow rate region. And replacing the denitration catalyst layer.

  According to the denitration facility and the catalyst replacement method of the present invention, nitrogen oxides can be efficiently removed for a longer period.

FIG. 1 is a schematic configuration diagram showing a pulverized coal fired boiler to which the denitration facility of the first embodiment is applied. FIG. 2 is a schematic configuration diagram showing the denitration facility of the first embodiment. FIG. 3 is a top view of the rectification and denitration catalyst layer. FIG. 4 is an enlarged top view showing an enlarged plate-like catalyst of the rectification and denitration catalyst layer. FIG. 5 is an enlarged top view showing the honeycomb catalyst of the denitration catalyst layer in an enlarged manner. FIG. 6 is a graph showing an example of conversion between operating time and denitration performance. FIG. 7 is a graph showing the relationship between the catalyst length and the transfer coefficient. FIG. 8 is a flowchart showing an example of a method for replacing the catalyst of the denitration facility. FIG. 9 is a schematic configuration diagram showing a denitration facility of the second embodiment. FIG. 10 is a flowchart illustrating an example of a catalyst replacement method for the denitration facility. FIG. 11 is a schematic configuration diagram illustrating a denitration facility of the third embodiment. FIG. 12 is a top view of the denitration catalyst layer. FIG. 13 is a graph showing the relationship between the denitration catalyst and the pressure loss. FIG. 14 is a flowchart illustrating an example of a catalyst replacement method for the denitration facility. FIG. 15 is a top view showing another example of the denitration catalyst of the fourth embodiment.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, this invention is not limited by this embodiment, and when there are two or more embodiments, what comprises combining each embodiment is also included.

[First Embodiment]
FIG. 1 is a schematic configuration diagram showing a pulverized coal fired boiler to which the denitration facility of the first embodiment is applied. The pulverized coal fired boiler to which the denitration facility of the first embodiment is applied uses pulverized coal obtained by pulverizing coal as a solid fuel, burns the pulverized coal with a combustion burner, and recovers heat generated by the combustion. It is a possible boiler. In addition, although demonstrated here applying the pulverized coal burning boiler, this invention is not limited to this type of boiler. The denitration facility can be used as a facility for removing nitrogen oxides from exhaust gas generated by burning fuel containing coal. Therefore, the combustor for burning the fuel is not limited to the boiler. Further, the fuel is not limited to burning only pulverized coal. The denitration facility can also be used as a facility for treating exhaust gas discharged from a co-firing combustor that mixes and burns coal, liquid fuel, and gaseous fuel as fuel.

  The pulverized coal burning boiler 10 according to the first embodiment is a conventional boiler as shown in FIG. 1 and includes a furnace 11 and a combustion device 12. The furnace 11 has a rectangular hollow shape and is installed along the vertical direction. A combustion device 12 is provided at the lower part of the furnace wall constituting the furnace 11.

  The combustion device 12 has a plurality of combustion burners 21 mounted on the furnace wall. In this embodiment, the combustion burners 21 are arranged at equal intervals along the circumferential direction as one set, and five sets along the vertical direction, that is, five stages are arranged.

  Each combustion burner 21 is connected to a pulverized coal supply device 30. The pulverized coal supply device 30 includes a pulverized coal supply pipe and a pulverized coal machine (mill), and supplies the pulverized coal from the pulverized coal machine to the fuel burner 21 via the pulverized coal supply pipe. The pulverized coal supply device 30 performs classification using carrier air (primary air), and supplies the classified pulverized coal and carrier air to the combustion burner 21.

  Further, the furnace 11 is provided with a wind box 36 at a position where each combustion burner 21 is mounted. One end of an air duct 37 is connected to the wind box 36, and the air duct 37 is connected to the other end. A blower 38 is attached. Therefore, the combustion air (secondary air and tertiary air) sent by the blower 38 can be supplied from the air duct 37 to the wind box 36 and supplied from the wind box 36 to each combustion burner 21.

  Therefore, in the combustion apparatus 12, each combustion burner 21 can blow a pulverized fuel mixture (fuel gas), which is a mixture of pulverized coal and primary air, into the furnace 11 and the secondary air into the furnace 11. A flame can be formed by igniting the pulverized fuel mixture with an ignition torch (not shown). In general, when the boiler is started, each combustion burner 21 injects oil fuel into the furnace 11 to form a flame.

  The furnace 11 has a flue 40 connected to the upper part, and a superheater (super heater) 41, 42 for recovering the heat of exhaust gas as a convection heat transfer part (heat recovery part) is connected to the flue 40. Heaters (reheaters) 43, 44 and economizers 45, 46, 47 are provided, and exhaust gas generated by combustion in the furnace 11 and water or steam flowing through the convection heat transfer section (heat recovery section) Heat exchange with the

  The flue 40 is connected to an exhaust gas pipe (exhaust gas passage) 48 through which the exhaust gas subjected to heat exchange is discharged downstream. The exhaust gas pipe 48 is provided with an air heater 49 between the air duct 37, performs heat exchange between the air flowing through the air duct 37 and the exhaust gas flowing through the exhaust gas pipe 48, and supplies the combustion burner 21 with heat. The temperature of the air can be raised.

  Further, in the exhaust gas pipe 48, a denitration facility 50 is provided at a position upstream of the air heater 49, and a dust treatment device (electric dust collector, desulfurization device) 51 and an induction blower 52 are provided at a position downstream of the air heater 49, and downstream A chimney 53 is provided at the end. The denitration facility 50 and the dust treatment device 51 function as a harmful substance removal unit. The denitration facility 50 will be described later.

  Exhaust gas G that has passed through the economizers 45, 46, 47 of the flue 40 is removed of harmful substances such as NOx by the denitration equipment 50 in the exhaust gas pipe 48, and particulate matter is removed by the dust treatment device 51. At the same time, after the sulfur content is removed, it is discharged from the chimney 53 into the atmosphere.

  In the pulverized coal-fired boiler 10 configured as described above, the downstream side (the flue 40) from the furnace 11 functions as the exhaust duct of the first embodiment. The flue 40 includes a first horizontal flue portion 40a, a first vertical flue portion 40b, a second horizontal flue portion 40c, a second vertical flue portion 40d, a third horizontal flue portion 40e, a third The vertical flue portion 40f and the fourth horizontal flue portion 40g are continuously provided. The third horizontal flue portion 40e is a folded portion that connects the second vertical flue portion 40d and the third vertical flue portion 40f, which have different vertical flow directions. Further, the exhaust gas G flows through the second vertical flue portion 40d toward the upper side in the vertical direction. In the third vertical flue section 40f, the exhaust gas G flows downward in the vertical direction.

  And in the flue 40, the superheaters 41 and 42, the reheaters 43 and 44, and the economizers 45, 46, and 47 are arrange | positioned at the 1st horizontal flue part 40a and the 1st vertical flue part 40b. . The flue 40 has a hopper 61 at the lower end of the first vertical flue portion 40b through which the exhaust gas G having a downward speed component flows, and the second vertical flue portion through which the exhaust gas G having an upward speed component flows. A hopper 62 is installed at the lower end of 40d. The hoppers 61 and 62 collect and store PA (solid particles) in the exhaust gas G falling from the first vertical flue portion 40b, the second vertical flue portion 40d, and the like. Further, in the flue 40, a part of the denitration facility 50 is installed in the third vertical flue portion 40f through which the exhaust gas G flows downward. In the flue 40, a part of the denitration facility 50 is disposed in the second vertical flue portion 40d.

  Next, the denitration facility 50 will be described with reference to FIGS. 2 to 5 in addition to FIG. FIG. 2 is a schematic configuration diagram showing the denitration facility of the first embodiment. FIG. 3 is a top view of the rectification and denitration catalyst layer. FIG. 4 is an enlarged top view showing an enlarged plate-like catalyst of the rectification and denitration catalyst layer. FIG. 5 is an enlarged top view showing the honeycomb catalyst of the denitration catalyst layer in an enlarged manner.

  The denitration facility 50 supplies a reducing agent having an action of reducing nitrogen oxides such as ammonia and urea water into the flue 40, and reacts the exhaust gas G supplied with the reducing agent with the nitrogen oxides and the reducing agent. By passing the selective catalytic reduction catalyst to be promoted, nitrogen oxides in the exhaust gas G are removed and reduced. As shown in FIGS. 1 and 2, the denitration facility 50 includes a reducing agent supply device 70, a rectifying and denitration catalyst layer 80, a first denitration catalyst layer 82, a second denitration catalyst layer 84, and a third denitration catalyst layer. 86, pressure gauges 140 and 146, nitrogen oxide concentration meter 148, control device 150, ammonia concentration meter 149, and notification unit 152.

  The reducing agent supply device 70 is a device that supplies the reducing agent into the flue 40. As the reducing agent, ammonia water, gaseous ammonia, urea water or the like can be used. In the reducing agent supply device 70, the supply port for supplying the reducing agent to the inside of the flue 40 is disposed in the second vertical flue portion 40d of the flue 40, and the reducing agent is discharged (spouted) from the supply port. A reducing agent is supplied into the second vertical flue section 40d. The reducing agent supplied from the reducing agent supply device 70 diffuses in the path through which the exhaust gas G flows while moving with the exhaust gas G.

  The rectification and denitration catalyst layer 80 is disposed in the third vertical flue portion 40 f of the flue 40. The rectification and denitration catalyst layer 80 flows from the third horizontal flue portion 40e into the third vertical flue portion 40f, rectifies the flow of the exhaust gas G whose flow direction changes, and reacts the nitrogen oxide with the reducing agent. To promote. The rectification and denitration catalyst layer 80 includes a plate-like catalyst 100 and a support mechanism 102 that fixes the plate-like catalyst 100 to the third vertical flue portion 40f. The support mechanism 102 may be any mechanism that can support the plate catalyst 100, and the structure is not particularly limited.

  As shown in FIG. 3, the plate-like catalyst 100 includes a plurality of catalyst packs 106 arranged in a matrix. The plate-like catalyst 100 is arranged so that the plurality of catalyst packs 106 cover the entire horizontal surface of the third vertical flue portion 40f. As a result, the exhaust gas G flowing through the third vertical flue section 40f passes through the catalyst pack 106. As shown in FIG. 4, the catalyst pack 106 of the plate catalyst 100 has a plurality of plates (for example, metal plates) 108 having a catalytic function along the direction of the exhaust gas (the direction perpendicular to the flow direction of the exhaust gas is the thickness of the plate). Are arranged in a direction. The catalyst pack 106 has a plurality of plates 108 arranged in parallel. Further, in the catalyst pack 106, the catalyst opening 107 between the plate 108 and the plate 108 arranged in parallel has a hydraulic diameter of 8 mm or more. The hydraulic diameter of the catalyst opening 107 of the plate catalyst 100 can be expressed by (4 × A) / L. A is the cross-sectional area of the opening, and L is the peripheral length (cross-sectional length). Further, in order to maintain a distance from the adjacent plate 108, the plurality of plates 108 are partially formed with a convex portion 109, and the convex portion 109 is in contact with the adjacent plate 108. The exhaust gas G passes between the plates 108 and 108 of the catalyst pack 106. Further, as shown in FIG. 4, when the pulverized coal burning boiler 10 is operated, the catalyst pack 106 of the plate catalyst 100 accumulates foreign matter 90 such as popcorn ash on the surface.

  The first denitration catalyst layer 82 is disposed downstream of the rectification and denitration catalyst layer 80 in the flow direction of the exhaust gas G. The first denitration catalyst layer 82 includes a honeycomb catalyst 110 and a support mechanism 112 that fixes the honeycomb catalyst 110 to the third vertical flue portion 40f. The support mechanism 112 may be any mechanism that can support the honeycomb catalyst 110, and the structure is not particularly limited.

  The honeycomb catalyst 110 has a plurality of catalyst packs similarly to the plate catalyst 100. The honeycomb catalyst 110 is also arranged so that a plurality of catalyst packs cover the entire horizontal surface of the third vertical flue portion 40f. Thus, the exhaust gas G flowing through the third vertical flue portion 40f passes through the catalyst pack of the honeycomb catalyst 110. As shown in FIG. 5, in the honeycomb catalyst 110, portions having a catalyst function are arranged in a lattice pattern. The exhaust gas G passes through the openings of the lattice having the catalytic function of the honeycomb catalyst 110. Here, in the honeycomb catalyst 110, the hydraulic diameter (4 × A) / L of the opening (catalyst opening) 117 through which the exhaust gas G passes is less than 8 mm.

  Here, the honeycomb catalyst 110 of the first denitration catalyst layer 82 is thicker than the plate catalyst 100. That is, W1 <W2 where W1 is the length of the plate catalyst 100 in the flow direction of the exhaust gas G and W2 is the length of the honeycomb catalyst 110 in the flow direction of the exhaust gas.

  The second denitration catalyst layer 84 is disposed downstream of the first denitration catalyst layer 82 in the flow direction of the exhaust gas G. The second denitration catalyst layer 84 includes a honeycomb catalyst 120 and a support mechanism 122 that fixes the honeycomb catalyst 120 to the third vertical flue portion 40f. The second denitration catalyst layer 84 is the same as the first denitration catalyst layer 82 except that the arrangement position is different. The third denitration catalyst layer 86 is arranged downstream of the second denitration catalyst layer 84 in the flow direction of the exhaust gas G. The third denitration catalyst layer 86 includes a honeycomb catalyst 130 and a support mechanism 132 that fixes the honeycomb catalyst 130 to the third vertical flue portion 40f. The third denitration catalyst layer 86 is the same as the first denitration catalyst layer 82 and the second denitration catalyst layer 84 except for the arrangement position. That is, in the denitration facility 50, three denitration catalyst layers are stacked on the downstream side of the rectification and denitration catalyst layer 80.

  The pressure gauge 140 is disposed on the upstream side of the rectification and denitration catalyst layer 80 of the third vertical flue portion 40f. The pressure gauge 140 measures the pressure of the exhaust gas G before flowing into the rectification and denitration catalyst layer 80. The pressure gauge 140 sends the measurement result to the control device 150.

  The pressure gauge 146 is disposed downstream of the third denitration catalyst layer 86 of the third vertical flue portion 40f. The pressure gauge 146 measures the pressure of the exhaust gas G after passing through the third denitration catalyst layer 86. The pressure gauge 146 sends the measurement result to the control device 150.

  The nitrogen oxide concentration meter 148 is disposed on the downstream side of the third denitration catalyst layer 86 of the third vertical flue portion 40f. The nitrogen oxide concentration meter 148 measures the nitrogen oxide concentration of the exhaust gas G after passing through the third denitration catalyst layer 86. As the nitrogen oxide concentration meter 148, a method of measuring the concentration by irradiating a laser beam having an absorption wavelength, measuring the concentration, obtaining a sampling gas from the exhaust gas G, a chemiluminescence method, an infrared absorption method, etc. Various methods, such as a continuous analyzer or a method of measuring the concentration by analyzing components by chemical analysis, can be used. The nitrogen oxide concentration meter 148 sends the measurement result to the control device 150.

  The ammonia concentration meter 149 is disposed on the downstream side of the third denitration catalyst layer 86 of the third vertical flue portion 40f. The ammonia concentration meter 149 measures the nitrogen oxide concentration of the exhaust gas G after passing through the third denitration catalyst layer 86. As the ammonia concentration meter 149, a method of measuring the concentration by irradiating a laser beam having an absorption wavelength, measuring the concentration, obtaining a sampling gas from the exhaust gas G, and a continuous analyzer using Fourier transform infrared spectroscopy, Various methods such as a method of analyzing the components by chemical analysis and measuring the concentration can be used. The ammonia concentration meter 149 sends the measurement result to the control device 150.

  The control device 150 is an arithmetic device such as a personal computer, and executes various processes by executing various control programs. The control device 150 determines an abnormality in the denitration facility 50 based on the result measured by the pressure gauges 140 and 146. Further, the control device 150 determines the state of the denitration facility 50 based on the results measured by the nitrogen oxide concentration meter 148 and the ammonia concentration meter 149, and determines the presence or absence of maintenance including replacement of the catalyst.

  The alerting | reporting part 152 alert | reports information to the manager of the denitration equipment 50, such as an operator. As the notification unit 152, various devices that output information can be used. For example, a display that displays an image, a speaker that outputs sound, a communication device that outputs via communication, and the like can be used.

  The denitration facility 50 arranges a rectification and denitration catalyst layer 80 having a rectification function and a denitration function on the upstream side of the first denitration catalyst layer 82, thereby rectifying the exhaust gas G flowing into the first denitration catalyst layer 82, Nitrogen oxide can be removed. Thereby, the denitration performance (performance which removes nitrogen oxides) of the denitration facility 50 can be increased. Further, by providing the rectification and denitration catalyst layer 80 having the rectification function and the denitration function, it is not necessary to arrange the rectification layer having only the rectification function, and the apparatus can be miniaturized.

  FIG. 6 is a graph showing an example of changes in operating time and denitration performance. In FIG. 6, the vertical axis represents the denitration performance characteristics, and the horizontal axis represents the operation time. FIG. 6 shows, as a comparative example, the result when a rectifying layer having no catalytic function is provided in place of the rectifying and denitrating catalyst layer 80 in addition to the result of the denitration facility of the present embodiment. As shown in FIG. 6, by providing the rectification and denitration catalyst layer 80, the denitration performance characteristics can be enhanced, and the operation time satisfying the required performance can be further prolonged.

  Further, the denitration facility 50 can increase durability when used as a rectification layer by using the plate-like catalyst 100 for the rectification and denitration catalyst layer 80. Specifically, when the flow of the exhaust gas G whose flow is disturbed is rectified, there is a high possibility that it will come into contact with foreign matter such as ash. Can be maintained for a long time. Further, the denitration facility 50 uses the plate-like catalyst 100 in the rectifying and denitration catalyst layer 80, so that an increase in pressure loss caused when foreign matter such as popcorn ash is stacked can be reduced, and the high performance is longer. Can be maintained for hours.

  In the rectification and denitration catalyst layer 80 of the present embodiment, the plate-like catalyst 100 is disposed, but is not limited thereto. In the rectification and denitration catalyst layer 80, the region where the exhaust gas G flows, that is, the hydraulic diameter of the catalyst opening portion may be larger than the hydraulic diameter of the catalyst opening portion of the honeycomb catalyst of the denitration catalyst layer arranged on the downstream side. Further, the rectification and denitration catalyst layer 80 preferably has a hydraulic diameter of the catalyst opening of 8 mm or more. The hydraulic diameter of the catalyst opening can be expressed by (4 × A) / L as described above. The shape of the catalyst opening varies depending on the type of catalyst. As the rectification and denitration catalyst layer 80, for example, a honeycomb catalyst (wide pitch honeycomb catalyst) having a wide arrangement interval in which the hydraulic diameter of the catalyst opening is 8 mm or more can be used.

  Here, the length W1 of the plate catalyst 100 in the flow direction of the exhaust gas G is preferably 50 mmL or more and 300 mmL or less. FIG. 7 is a graph showing the relationship between the catalyst length and the mass transfer coefficient. As shown in FIG. 7, the transfer coefficient of the substance can be lowered by setting the length of the exhaust gas G in the flow direction to 50 mmL. That is, the flow of the exhaust gas G can be rectified. Moreover, it can suppress that the rectification and denitration catalyst layer 80 becomes longer than necessary by setting it as 300 mmL.

  Further, the denitration facility 50 of this embodiment includes three denitration catalysts, a first denitration catalyst layer 82, a second denitration catalyst layer 84, and a third denitration catalyst layer 86, downstream of the rectification and denitration catalyst layer 80. Although the layers are arranged, the number of denitration catalyst layers is not limited to three. One or more denitration catalyst layers may be disposed, and two denitration catalyst layers may be disposed, or four or more denitration catalyst layers may be disposed.

  Further, in the denitration facility 50, the exhaust gas preferably flows from the upper side to the lower side in the vertical direction as in the exhaust gas passage, this embodiment. That is, it is preferable that the flue in the region where the denitration catalyst layer is disposed extends in the vertical direction, and the exhaust gas flows through the flue from the upper side to the lower side in the vertical direction. Thereby, it becomes easy for a foreign material to fall, and it can suppress that a foreign material accumulates on a denitration catalyst layer. From the above, catalyst wear can be suppressed, and an increase in pressure loss due to foreign matter can be suppressed. Since the denitration facility 50 can obtain the above-described effect, it is preferable to use an exhaust gas passage in which exhaust gas flows from the upper side to the lower side in the vertical direction, but the present invention is not limited to this. The denitration facility 50 may be an exhaust gas passage through which exhaust gas flows in a direction inclined with respect to the vertical direction. That is, the flue gas flue in the region where the denitration catalyst layer is disposed may be inclined with respect to the vertical direction.

  Next, an example of a method for replacing the catalyst of the denitration facility 50 will be described with reference to FIG. FIG. 8 is a flowchart showing an example of a method for replacing the catalyst of the denitration facility. The processing shown in FIG. 8 can determine whether maintenance is necessary using the control device 150. Also, the operator replaces the catalyst. Further, the process shown in FIG. 8 can be executed even when the rectification and denitration catalyst layer 80 of the denitration facility 50 is in a rectification layer that does not have a catalytic function.

  The control device 150 measures the ammonia concentration and the nitrogen oxide concentration (step S12). The control device 150 detects the nitrogen oxide concentration of the exhaust gas G that has passed through the third denitration catalyst layer 86 based on the detection result of the nitrogen oxide concentration meter 148. Further, the control device 150 detects the ammonia concentration of the exhaust gas G that has passed through the third denitration catalyst layer 86 based on the detection result of the ammonia concentration meter 149.

  The control device 150 determines whether maintenance is necessary based on the detected ammonia concentration and nitrogen oxide concentration (step S14). The control device 150 determines the entire denitration performance of the layer having the denitration function based on the ammonia concentration and the nitrogen oxide concentration. Further, the control device 150 outputs the determination result to the notification unit, and the operator extracts and inspects a part of each catalyst layer based on the information, acquires the result, and determines whether maintenance is necessary. Good.

  When it is determined that the maintenance is not necessary (No in Step S14), the control device 150 returns to Step S12 and performs the process of Step S12. If it is determined that maintenance is required (Yes in step S14), the control device 14 determines whether the rectifying layer can be replaced (step S16). The controller 150 determines that the rectifying layer is replaceable when the rectifying layer does not have the denitration function or when the denitration function is lowered.

  When it is determined that the rectifying layer can be replaced (Yes in step S16), the control device 150 replaces the rectifying layer with a rectifying and denitration catalyst layer (step S18). When it is determined that the rectifying layer is not replaceable (No in step S16), control device 150 replaces the denitration catalyst layer (first denitration catalyst layer 82, second denitration catalyst layer 84, and third denitration catalyst layer 86). (Step S20). In the present embodiment, the denitration catalyst layer is replaced, but a new denitration catalyst layer may be added.

  As shown in FIG. 8, by replacing the rectification layer with a rectification and denitration catalyst layer, it is possible to improve the denitration performance while suppressing an increase in the size of the apparatus. In addition, as described above, the hydraulic diameter of the opening through which the exhaust gas G passes through the rectification / denitration catalyst layer is 8 mm or more, preferably a plate-shaped catalyst, so that durability can be enhanced.

  In the process illustrated in FIG. 8, whether to perform maintenance is determined based on the differential pressure and the nitrogen oxide concentration, but is not limited thereto. The control device 150 may determine whether to perform maintenance based on the operation time or usage period.

[Second Embodiment]
FIG. 9 is a schematic configuration diagram showing a denitration facility of the second embodiment. In addition, the same code | symbol is attached | subjected to the member which has the same function as embodiment mentioned above, and detailed description is abbreviate | omitted.

  A denitration facility 50a shown in FIG. 9 includes a reducing agent supply device 70, a rectifying layer 160, a first denitration catalyst layer 82a, a second denitration catalyst layer 84, a third denitration catalyst layer 86, and pressure gauges 140 and 146. A nitrogen oxide concentration meter 148, an ammonia concentration meter 149, a control device 150, and a notification unit 152. The reducing agent supply device 70, the second denitration catalyst layer 84, the third denitration catalyst layer 86, the pressure gauges 140 and 146, the nitrogen oxide concentration meter 148, the control device 150, and the ammonia concentration meter of the denitration facility 50a. Since 149 and the notification unit 152 have the same functions as the denitration facility 50, description thereof will be omitted.

  The rectifying layer 160 is disposed in the third vertical flue portion 40 f of the flue 40. The rectifying layer 160 is disposed at the same position as the rectifying and denitration catalyst layer 80. The rectifying layer 160 flows into the third vertical flue portion 40f from the third horizontal flue portion 40e, and rectifies the flow of the exhaust gas G whose flow direction changes. In the rectifying layer 160, plates extending in the extending direction of the third vertical flue portion 40f are arranged in a row in a direction orthogonal to the extending direction.

  The first denitration catalyst layer 82a includes a plate catalyst 110a and a support mechanism 112a that fixes the plate catalyst 110a to the third vertical flue portion 40f. The support mechanism 112a may be a mechanism that can support the plate catalyst 110a, and the structure is not particularly limited. The plate catalyst 110 a has the same structure as the plate catalyst 100. The length of the plate catalyst 110a in the flow direction of the exhaust gas G is the same as that of the honeycomb catalysts 120 and 130 of the second denitration catalyst layer 84 and the denitration catalyst layer 86.

  The denitration facility 50a uses the first denitration catalyst layer 82a, which is the most upstream denitration catalyst in the flow direction of the exhaust gas G, as the plate catalyst 110a. The pressure loss can be suppressed. Specifically, by using the plate-like catalyst 110a, it is possible to suppress an increase in pressure loss in the denitration catalyst layer even when the same foreign matter (popcorn ash or the like) comes in than when the honeycomb catalyst is arranged. . In the denitration facility 50a, the downstream denitration catalyst in the flow direction of the exhaust gas G is a honeycomb catalyst, so that the surface area of the catalyst can be increased and the denitration performance can be enhanced.

  In the denitration facility 50a of the above embodiment, the first denitration catalyst layer 82a is a plate catalyst, and the second denitration catalyst layer 84 and the third denitration catalyst layer 86 are honeycomb catalysts. However, the present invention is not limited to this. The denitration facility 50a includes both a denitration catalyst layer of the honeycomb catalyst and a denitration catalyst layer of the plate catalyst, and the denitration catalyst of the plate catalyst is upstream of the denitration catalyst layer of the honeycomb catalyst in the flow direction of the exhaust gas G. It only has to be arranged. That is, in the denitration facility 50, the honeycomb catalyst is not arranged on the upstream side of the plate catalyst, in other words, only the plate catalyst needs to be arranged on the upstream side of the plate catalyst.

  Next, an example of a catalyst replacement method for the denitration facility 50a will be described with reference to FIG. FIG. 10 is a flowchart illustrating an example of a catalyst replacement method for the denitration facility. The processing shown in FIG. 10 can determine whether maintenance is necessary or not using the control device 150. Also, the operator replaces the catalyst. Further, the process shown in FIG. 10 can be executed even when the first denitration catalyst layer 82a of the denitration facility 50a is a honeycomb catalyst.

  The control device 150 measures the ammonia concentration and the nitrogen oxide concentration (step S12). The control device 150 determines whether maintenance is necessary based on the detected ammonia concentration and nitrogen oxide concentration (step S14).

  When it is determined that the maintenance is not necessary (No in Step S14), the control device 150 returns to Step S12 and performs the process of Step S12. When it is determined that maintenance is necessary (Yes in step S14), the controller 150 checks each catalyst layer and identifies the catalyst layer to be replaced (step S30). Specifically, it is determined which one of the first denitration catalyst layer 82a, the second denitration catalyst layer 84, and the third denitration catalyst layer 86 is to be replaced. One or more catalyst layers may be exchanged. Moreover, you may determine the catalyst layer to replace | exchange without performing an inspection etc.

  When the catalyst layer to be exchanged is specified, it is determined whether all the downstream catalysts are honeycomb-type catalysts (step S32). When it is determined that the downstream side catalysts are all honeycomb type catalysts (Yes in step S32), the control device 150 replaces the catalyst layer to be replaced with a plate catalyst (step S34). When it is determined that the downstream side catalysts are not all honeycomb type catalysts (No in step S32), the control device 150 replaces the catalyst layer to be replaced with the honeycomb type catalyst (step S36).

  As shown in FIG. 10, by replacing the denitration catalyst layer of the denitration facility, the exhaust gas passes through the plate catalyst and then passes through the honeycomb catalyst. For example, when all the denitration catalyst layers are honeycomb catalysts, the upstream denitration catalyst layer is replaced with a plate catalyst. When all the denitration catalyst layers are plate-shaped catalysts, the downstream denitration catalyst layer is replaced with a honeycomb catalyst. Thereby, denitration performance can be maintained high while suppressing the occurrence of pressure loss due to adhesion of foreign matter. Thereby, it is possible to operate for a long period of time while maintaining high denitration performance. In addition, although the above-described process has been described as a process at the time of replacement of the denitration catalyst layer, both a honeycomb catalyst and a plate-like catalyst may be provided at the time of manufacture and arranged in the above-described layout.

[Third Embodiment]
FIG. 11 is a schematic configuration diagram illustrating a denitration facility of the third embodiment. FIG. 12 is a top view of the denitration catalyst layer. In addition, the same code | symbol is attached | subjected to the member which has the same function as embodiment mentioned above, and detailed description is abbreviate | omitted.

  11 includes a reducing agent supply device 70, a rectifying layer 160, a first denitration catalyst layer 182, a second denitration catalyst layer 184, a third denitration catalyst layer 186, and pressure gauges 140 and 146. A nitrogen oxide concentration meter 148, an ammonia concentration meter 149, a control device 150, and a notification unit 152. The reducing agent supply device 70, the pressure gauges 140 and 146, the nitrogen oxide concentration meter 148, the control device 150, the ammonia concentration meter 149, and the notification unit 152 of the denitration facility 50b are the same as the denitration facility 50. Since it is a function, description thereof is omitted.

  The rectifying layer 160 is disposed in the third vertical flue portion 40 f of the flue 40. The rectifying layer 160 is disposed at the same position as the rectifying and denitration catalyst layer 80. The rectifying layer 160 flows into the third vertical flue portion 40f from the third horizontal flue portion 40e, and rectifies the flow of the exhaust gas G whose flow direction changes. In the rectifying layer 160, plates extending in the extending direction of the third vertical flue portion 40f are arranged in a row in a direction orthogonal to the extending direction.

  The first denitration catalyst layer 182 includes a catalyst unit 210 and a support mechanism 212 that fixes the catalyst unit 210 to the third vertical flue portion 40f. The support mechanism 212 may be a mechanism that can support the catalyst unit 210, and the structure is not particularly limited.

  The catalyst unit 210 includes a plate catalyst 250 and a honeycomb catalyst 252. The plate-like catalyst 250 has a plurality of catalyst packs 250a. The honeycomb catalyst 252 has a plurality of catalyst packs 252a. In the catalyst unit 210, as shown in FIG. 12, the catalyst pack 250a of the plate catalyst 250 and the catalyst pack 252a of the honeycomb catalyst 252 are arranged in a matrix. The catalyst unit 210 is arranged such that the plurality of catalyst packs 250a and 252a block the entire horizontal surface of the third vertical flue portion 40f. Thereby, the exhaust gas G flowing through the third vertical flue portion 40f passes through the plate catalyst 250 or the honeycomb catalyst 252.

  Here, the catalyst unit 210 is upstream of the third vertical flue portion 40f, which is a region where the denitration catalyst layer of the exhaust gas passage 40 is disposed, and the second vertical flue portion 40d and the third vertical flue portion 40d, which are upstream regions. The plate-like catalyst 250 is disposed in the region where the horizontal flue portion 40e is disposed, and the honeycomb catalyst 252 is disposed in the region opposite to the side where the upstream region is disposed. The catalyst unit 210 of the present embodiment is inclined with respect to the vertical direction on the upstream side of the third vertical flue portion 40f, which is a region where the denitration catalyst layer of the exhaust gas passage 40 is disposed (in the present embodiment, horizontal) The plate-like catalyst 250 is arranged in the area on the side where the third horizontal flue portion 40e is arranged, and the honeycomb catalyst 252 is arranged in the area opposite to the side where the upstream area is arranged. Has been. Here, the side on which the upstream region is arranged is the side on which the upstream exhaust gas flows. In the present embodiment, on the side where the upstream region is disposed, the upstream region (third horizontal flue portion 40e) is inclined with respect to the region (third vertical flue portion 40f) where the denitration catalyst layer is disposed. On the side.

  Due to the structure of the flue 40, the flow rate of the exhaust gas G is slower than the flow rate in the region opposite to the side where the upstream region is disposed in the region where the upstream region is disposed. Moreover, the area | region where the upstream area | region is arrange | positioned turns into an area | region where the flow velocity is relatively slow with respect to the average flow velocity of the exhaust gas flowing through the denitration catalyst layer. It can be said that the region opposite to the side where the upstream region is disposed is a region having a relatively high flow rate with respect to the average flow rate.

  In the catalyst unit 210, when viewed from the flow direction of the exhaust gas G, the plate catalyst 250 and the honeycomb catalyst 252 are arranged in the same area. The area ratio between the plate catalyst 250 and the honeycomb catalyst 252 is not limited to 1: 1. The catalyst unit 210 has an average flow rate that the plate-like catalyst 250 is arranged at 1% or more and 50% or less of the whole, or the honeycomb-like 252 is arranged at 1% or more and 50% or less of the whole. This is preferable from the viewpoint of increasing the effect.

  Moreover, it is preferable that the catalyst unit 210 adjusts whether the plate-shaped catalyst 250 or the honeycomb catalyst 252 is arranged on a catalyst pack basis. As a result, the catalyst pack can be easily replaced.

  The second denitration catalyst layer 184 includes a catalyst unit 220 and a support mechanism 222 that fixes the catalyst unit 220 to the third vertical flue portion 40f. The support mechanism 222 may be a mechanism that can support the catalyst unit 220, and the structure is not particularly limited. The catalyst unit 220 includes a plate catalyst 260 and a honeycomb catalyst 262. The second denitration catalyst layer 184 is the same as the first denitration catalyst layer 182 except that the arrangement position is different.

  The third denitration catalyst layer 186 includes a catalyst unit 230 and a support mechanism 232 that fixes the catalyst unit 230 to the third vertical flue portion 40f. The support mechanism 232 may be any mechanism that can support the catalyst unit 230, and the structure is not particularly limited. The catalyst unit 230 includes a plate catalyst 270 and a honeycomb catalyst 272. The third denitration catalyst layer 186 is the same as the first denitration catalyst layer 182 except for the arrangement position.

  In the denitration facility 50b, the plate-like catalysts 250, 260, 270 are disposed in the region where the upstream region is disposed, and the honeycomb catalysts 252, 262, 272 are disposed in the region opposite to the side where the upstream region is disposed. Therefore, the honeycomb catalysts 252, 262, and 272 can be disposed in a region where the exhaust gas G has a high flow rate, and the plate catalysts 250, 260, and 270 can be disposed in a region where the exhaust gas G has a low flow rate. Thereby, the plate-like catalysts 250, 260, and 270 can be arranged in a region where the speed of the exhaust gas G where foreign substances are easily deposited is low. The plate-like catalysts 250, 260, and 270 are less likely to deposit foreign matter than the honeycomb catalysts 252, 262, and 272, and the pressure loss is less increased when they are deposited. Thereby, by disposing the plate catalysts 250, 260, and 270 in a region where the flow rate is slow, accumulation of foreign matters can be suppressed and an increase in pressure loss can be reduced, so that the denitration performance can be maintained for a long period of time. In addition, the NOx removal performance can be improved by disposing the honeycomb catalysts 252, 262, and 272 in a region where the flow rate is difficult to deposit foreign matter.

  FIG. 13 is a graph showing the relationship between the denitration catalyst and the pressure loss. As shown in FIG. 13, the honeycomb catalyst and the plate catalyst have a larger pressure loss than the plate catalyst. That is, the honeycomb catalyst is less likely to flow exhaust gas than the plate catalyst. The denitration facility 50b can make the flow rate uniform by arranging the honeycomb catalyst in the region where the flow rate of the exhaust gas G is high and arranging the plate catalyst in the region where the flow rate of the exhaust gas G is low. In addition, since the exhaust gas G is less likely to flow through the honeycomb catalyst than the plate-like catalyst, the flow rate of the exhaust gas G can be slowed down and the wear of the catalyst can be suppressed. In addition, since the plate-shaped catalyst has little pressure loss, it is possible to suppress a reduction in flow velocity and to suppress foreign matter accumulation.

  Further, in the denitration facility 50b, when viewed from the flow direction of the exhaust gas G, it is preferable that the plate catalyst region and the honeycomb catalyst region of the plurality of denitration catalyst layers are the same region. Thereby, it can suppress that many foreign materials accumulate on the downstream honeycomb catalyst.

  Next, an example of a method for replacing the catalyst of the denitration facility 50b will be described with reference to FIG. FIG. 14 is a flowchart illustrating an example of a catalyst replacement method for the denitration facility. In the process shown in FIG. 14, it is possible to determine whether maintenance is necessary using the control device 150. Also, the operator replaces the catalyst. Further, the process shown in FIG. 14 can be executed even when each layer of the denitration catalyst layer of the denitration facility 50b is composed of only the honeycomb catalyst or only the plate catalyst.

  The control device 150 measures the ammonia concentration and the nitrogen oxide concentration (step S12). The control device 150 determines whether maintenance is necessary based on the detected ammonia concentration and nitrogen oxide concentration (step S14). When it is determined that the maintenance is not necessary (No in Step S14), the control device 150 returns to Step S12 and performs the process of Step S12.

  When it is determined that the maintenance is necessary (Yes in Step S14), the operator checks each catalyst layer and specifies the catalyst layer to be replaced (Step S40). Specifically, it is determined which one of the first denitration catalyst layer 82a, the second denitration catalyst layer 84, and the third denitration catalyst layer 86 is to be replaced. One or more catalyst layers may be exchanged. Moreover, you may determine the catalyst layer to replace | exchange without performing an inspection etc.

  When the catalyst layer to be exchanged is specified, the arrangement of the plate catalyst and the honeycomb catalyst is determined (step S42). The control device 150 determines the arrangement so that the plate catalyst is arranged in a region where the flow rate is relatively slow and the honeycomb catalyst is arranged in a region where the flow rate is relatively fast. Next, when the arrangement of the plate catalyst and the honeycomb catalyst is determined, the catalyst layer in which the plate catalyst and the honeycomb catalyst are arranged is replaced with the specified catalyst layer based on the determination (step S44).

  As shown in FIG. 14, one denitration catalyst layer has both a honeycomb catalyst and a plate catalyst, and the plate catalyst is disposed in a region where the flow rate is relatively slow, so that the flow rate is relatively high. By disposing the honeycomb catalyst, it is possible to increase the denitration performance while making the flow rate uniform and increasing the durability. That is, by disposing the plate-like catalyst in the portion where the flow rate is slow, it is difficult for foreign matter to accumulate and even if it accumulates, it is difficult to increase the pressure loss. In addition, by disposing the honeycomb catalyst in a portion where the flow rate is high, the pressure loss can be increased to reduce the flow rate, and the surface area of the catalyst can be increased to improve the denitration performance. In addition, although the above-described process has been described as a process at the time of replacement of the denitration catalyst layer, both a honeycomb catalyst and a plate-like catalyst may be provided at the time of manufacture and arranged in the above-described layout.

[Fourth Embodiment]
FIG. 15 is a top view showing another example of the denitration catalyst of the fourth embodiment. In addition, the same code | symbol is attached | subjected to the member which has the same function as embodiment mentioned above, and detailed description is abbreviate | omitted. The fourth embodiment shows only the denitration catalyst of the denitration facility. The denitration catalyst of the present embodiment is preferably arranged in place of the above-described honeycomb catalyst.

  A denitration catalyst 302 shown in FIG. 15 includes a plate catalyst 310 and a honeycomb catalyst 312 arranged on the downstream side of the plate catalyst 310 in the flow direction of the exhaust gas G. In the denitration catalyst 302, the downstream surface of the plate catalyst 310 in the flow direction of the exhaust gas G and the upstream surface of the honeycomb catalyst 312 in the flow direction of the exhaust gas are close to each other. At least a part of the plate catalyst 310 and the honeycomb catalyst 312 may be in contact with each other. The exhaust gas G passes through the honeycomb catalyst 312 after passing through the plate catalyst 310.

  The denitration catalyst 302 is arranged in a state where the plate catalyst 310 is close to the upstream side of the honeycomb catalyst 312 in the flow direction of the exhaust gas G, so that the exhaust gas G whose flow is rectified by the plate catalyst 310 flows into the honeycomb catalyst 312. be able to. Accordingly, the wear resistance of the honeycomb catalyst 312 on the upstream side in the flow direction of the exhaust gas G of the NOx removal catalyst 302 can be enhanced without reinforcing the end face on the upstream side in the flow direction of the exhaust gas G. Moreover, the plate-shaped catalyst 310 can maintain the performance as a catalyst high by not performing the surface coating etc. Further, by arranging the plate-like catalyst 310, it is possible to suppress an increase in pressure loss even when foreign matter is accumulated.

  Here, the length of the plate catalyst 310 in the flow direction of the exhaust gas G is preferably 50 mmL or more and 300 mmL or less. As shown in FIG. 7 described above, the transfer coefficient of the substance can be lowered by setting the length of the exhaust gas G in the flow direction to 50 mmL. That is, the flow of the exhaust gas G can be rectified. Moreover, it can suppress that the plate-shaped catalyst 310 becomes longer than necessary by setting it as 300 mmL.

10 Pulverized coal fired boiler 11 Furnace 21 Combustion burner 40 Flue (exhaust gas passage)
41, 42 Superheater (heat recovery part)
43, 44 Reheater (Heat recovery part)
45, 46, 47 Energy-saving equipment (heat recovery part)
50, 50a, 50b Denitration equipment 61, 62 Hopper 70 Reducing agent supply device 80 Rectification and denitration catalyst layer 82, 82a, 182 First denitration catalyst layer 84, 184 Second denitration catalyst layer 86, 186 Third denitration catalyst layer 100, 110a, 250, 260, 270, 310 Plate catalyst 102, 112, 112a, 122, 132, 162, 212, 222, 232 Support mechanism 110, 120, 130, 232, 252, 262, 272, 312 Honeycomb catalyst 150 Control Device 152 Notification unit 160 Rectifying layer

Claims (13)

An exhaust gas passage through which exhaust gas flows;
A rectification and denitration catalyst layer installed in the exhaust gas passage;
And at least one denitration catalyst layer disposed downstream of the rectification and denitration catalyst layer in the exhaust gas passage in the flow direction of the exhaust gas,
The denitrification facility, wherein the flow straightening / denitration catalyst layer has a length in the flow direction of the exhaust gas shorter than that of the denitration catalyst layer.   2. The denitration facility according to claim 1, wherein the rectification and denitration catalyst layer has a hydraulic diameter of a catalyst opening portion larger than a hydraulic diameter of a catalyst opening portion of the denitration catalyst layer.   2. The denitration equipment according to claim 1, wherein the rectification and denitration catalyst layer has a hydraulic diameter of a catalyst opening of 8 mm or more. The rectification and denitration catalyst layer is a plate catalyst,
The denitration facility according to any one of claims 1 to 3, wherein the denitration catalyst layer is a honeycomb catalyst. An exhaust gas passage through which exhaust gas flows;
A rectifying layer installed in the exhaust gas passage;
And at least two denitration catalyst layers disposed downstream of the rectifying layer in the exhaust gas passage in the exhaust gas flow direction,
The at least two denitration catalyst layers are:
The most upstream denitration catalyst layer in the flow direction of the exhaust gas is a plate catalyst,
The most downstream denitration catalyst layer in the exhaust gas flow direction is composed of a honeycomb catalyst,
The denitration catalyst layer of all the plate-shaped catalysts is arranged upstream of the denitration catalyst layer of the honeycomb catalyst in the exhaust gas flow direction. An exhaust gas passage through which exhaust gas flows;
A rectifying layer installed in the exhaust gas passage;
And at least one denitration catalyst layer disposed downstream of the rectifying layer of the exhaust gas passage in the exhaust gas flow direction,
A plate catalyst is disposed in a region where the flow rate is relatively slow with respect to the average flow rate of the exhaust gas flowing through the denitration catalyst layer, and a honeycomb catalyst is disposed in a region where the flow rate is relatively fast with respect to the average flow rate. Denitration equipment characterized by that. An exhaust gas passage through which exhaust gas flows;
A rectifying layer installed in the exhaust gas passage;
And at least one denitration catalyst layer disposed downstream of the rectifying layer of the exhaust gas passage in the exhaust gas flow direction,
The denitration catalyst layer is a laminate of a plate catalyst and a honeycomb catalyst,
The plate-like catalyst is disposed upstream of the honeycomb catalyst in the flow direction of the exhaust gas, and the end surface on the plate-like catalyst side is close to the honeycomb catalyst.   The denitration facility according to any one of claims 1 to 7, wherein the exhaust gas passage is arranged so that the exhaust gas flows from the upper side to the lower side in the vertical direction. A denitration equipment catalyst replacement method comprising a rectification layer and a denitration catalyst layer disposed downstream of the rectification layer in the exhaust gas flow direction,
Determining whether the rectifying layer has a catalytic function;
And a step of replacing the rectifying layer with a rectifying and denitrating catalyst layer having a function of a denitration catalyst when the rectifying layer does not have a catalyst function.   The catalyst replacement method according to claim 9, wherein the step of replacing the rectification and denitration catalyst layer is performed by replacing the rectification and denitration catalyst layer with a hydraulic diameter of a catalyst opening of 8 mm or more.   The catalyst replacement method according to claim 9 or 10, wherein the step of replacing the rectification and denitration catalyst layer with a plate-shaped catalyst is performed. A method for replacing a catalyst in a denitration facility comprising a rectification layer and at least two denitration catalyst layers disposed downstream of the rectification layer in the flow direction of exhaust gas,
Identifying the denitration catalyst layer to be replaced;
And a step of replacing the denitration catalyst layer to be replaced with a plate-shaped catalyst when there is no honeycomb catalyst upstream in the flow direction of the exhaust gas. A method for replacing a catalyst of a denitration facility, comprising: a rectification layer; and at least one denitration catalyst layer disposed downstream of the rectification layer in a flow direction of exhaust gas,
Identifying the denitration catalyst layer to be replaced;
The denitration catalyst layer identified in the identifying step is a plate-shaped catalyst in which the flow rate is relatively slow with respect to the average flow rate of the exhaust gas flowing through the denitration catalyst layer, and the flow rate is relatively high with respect to the average flow rate. And a step of replacing the denitration catalyst layer with a honeycomb catalyst region as a fast catalyst region.

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