Plate heat exchanger, method for removing CO from tail gas diffused by dry quenching and method for removing CO from sintering flue gas

Abstract

The invention relates to a plate heat exchanger, a dry quenching diffused tail gas CO removal method and a sintering flue gas CO removal method.The plate heat exchanger comprises a plurality of heat exchange plate assemblies, each heat exchange plate assembly comprises two heat exchange plates, a heat exchange medium channel is arranged between the two heat exchange plates, and a flue gas channel is arranged between every two adjacent heat exchange plate assemblies; the heat exchange medium channels and the flue gas channels are alternately arranged, the surfaces, facing the flue gas channels, of the heat exchange plates are reaction faces, the reaction faces are non-planar so that the reaction faces can generate turbulent flow on flue gas flowing through the flue gas channels, and catalysts are attached to the reaction faces. The reaction surface intensifies the flue gas turbulence effect to ensure that the flue gas in the flue gas channel can be in full contact with the catalyst, so that the reaction gas in the flue gas is quickly catalyzed and combusted in the catalyst micropores to release heat, and the catalytic reaction speed and the reaction efficiency are improved. The heat is in contact with the heat exchange plate, so that the wall temperature of the heat exchange plate is directly increased, the heat exchange effect is improved, and efficient waste heat recycling is achieved.

Description

Technical Field

[0001] The present invention relates to the field of environmental protection, and in particular to a plate heat exchanger, a method for removing CO from coke dry quenching exhaust gas, and a method for removing CO from sintering flue gas. Background Art

[0002] Carbon oxide pollution includes CO (carbon monoxide) and CO2 (carbon dioxide) pollution to the atmosphere. CO is a colorless, odorless toxic gas with relatively stable chemical properties. The main man-made sources of CO are fossil fuel combustion, petroleum refining, steel smelting, solid waste incineration, etc. CO is currently the largest atmospheric pollutant emitted.

[0003] At present, the catalyst for removing carbon monoxide from industrial flue gas generally adopts a honeycomb structure with 30 to 50 holes. Since the catalytic combustion reaction of CO is achieved by physical adsorption and chemical adsorption on the catalyst surface to release heat through catalytic combustion, a large amount of heat accumulates in the catalyst body and affects the activity of the catalyst. In addition, the CO removal catalyst adopts a honeycomb structure. This straight-through catalyst structure cannot achieve flue gas turbulence. It can only improve the carbon monoxide removal effect by reducing the catalyst pore size and increasing the reaction ratio of carbon monoxide on the catalyst surface. However, due to the large number of catalyst holes, the catalyst resistance is high, resulting in an increase in system resistance and power consumption.

[0004] At the same time, after the catalytic combustion of carbon monoxide releases heat, the reaction temperature is generally 250-400°C. Generally, a separate heat exchanger is required to absorb the waste heat of the flue gas, that is, the catalyst and the heat exchanger are separately set structures to achieve the purpose of controllable CO catalyst reaction temperature and realize stable CO removal, which makes the overall system complex, occupies a large area and requires a large investment. Summary of the invention

[0005] The object of the present invention is to provide a plate heat exchanger, a method for removing CO from coke dry quenching exhaust gas, and a method for removing CO from sintering flue gas, so as to solve the problems of slow reaction speed of CO catalytic combustion in flue gas without turbulence, uncontrollable reaction temperature and low efficiency, and the catalyst and heat exchanger being separately arranged structures, occupying a large area and requiring high investment.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions.

[0007] The present invention provides a plate heat exchanger, which includes multiple groups of heat exchange plate assemblies, each group of the heat exchange plate assemblies includes two heat exchange plates, a heat exchange medium channel is provided between the two heat exchange plates, a flue gas channel is provided between two adjacent groups of the heat exchange plate assemblies, the heat exchange medium channel and the flue gas channel are arranged alternately, the surface of the heat exchange plate facing the flue gas channel is a reaction surface, the reaction surface is a non-planar surface so that the reaction surface can generate turbulence to the flue gas flowing through the flue gas channel, and a catalyst is attached to the reaction surface.

[0008] In some embodiments of the present application, the heat exchange plate is wavy.

[0009] In some embodiments of the present application, the heat exchange plate has alternately arranged crests and troughs, and the extension direction of the trajectory of each crest and the extension direction of the trajectory of each trough are the same as the direction from the inlet to the outlet of the flue gas channel.

[0010] In some embodiments of the present application, each group of the heat exchange plate assembly includes two sealing plates, which are respectively arranged at both ends of the heat exchange medium channel. The sealing plates connect the two heat exchange plates in each group of the heat exchange plate assembly, and the sealing plates prevent flue gas from entering the heat exchange medium channel.

[0011] In some embodiments of the present application, two plate heat exchangers are provided, namely a primary plate heat exchanger and a secondary plate heat exchanger, and the heat exchange medium channel of the primary plate heat exchanger is connected to the heat exchange medium channel of the secondary plate heat exchanger.

[0012] In some embodiments of the present application, the reaction surface has raised textures.

[0013] In some embodiments of the present application, the catalyst is a carbon monoxide removal catalyst and / or a denitrification catalyst;

[0014] The catalyst is attached to the reaction surface by coating, dipping or spraying.

[0015] In some embodiments of the present application, the surface of the heat exchange plate facing the heat exchange medium channel is a non-reactive surface, and the non-reactive surface is a plane or a non-plane;

[0016] The heat exchange medium in the heat exchange medium channel is gas or liquid.

[0017] The present invention also provides a method for removing CO from tail gas emitted by dry quenching of coke, comprising a heating furnace and a plate heat exchanger as described in any of the above embodiments, wherein the plate heat exchanger is provided with two, namely a primary plate heat exchanger and a secondary plate heat exchanger;

[0018] During the startup phase, the flue gas after CDQ desulfurization enters the heating furnace through the flue, and the heating furnace heats the flue gas temperature and the flue gas enters the flue gas channel of the primary plate heat exchanger. The flue gas undergoes a carbon monoxide removal reaction in the flue gas channel of the primary plate heat exchanger while releasing heat, and the flue gas temperature is further increased. The flue gas then enters the flue gas channel of the secondary plate heat exchanger to further remove CO and release heat. After the system temperature is increased, a heat exchange medium is introduced into the heat exchange medium channel of the secondary plate heat exchanger. The heat exchange medium first absorbs the heat of the flue gas in the flue gas channel of the secondary plate heat exchanger, and the flue gas temperature is reduced, while the heat exchange medium temperature is increased. After the temperature is increased, the heat exchange medium enters the heat exchange medium channel of the primary plate heat exchanger to release heat into the flue gas, thereby increasing the flue gas temperature and allowing the CO removal reaction to occur continuously.

[0019] After the startup phase is over, the heating furnace is turned off, and the heat exchange medium in the heat exchange medium channel of the primary plate heat exchanger is sent to the energy recovery system for heat utilization.

[0020] The present invention also provides a method for removing CO from sintering flue gas, comprising a flue gas heat exchanger, a heating furnace, a plate heat exchanger as described in any of the above embodiments, an ammonia generator, an ammonia injection grid, a denitration reactor and an induced draft fan;

[0021] In the startup stage, the flue gas after sintering and desulfurization enters the flue gas heat exchanger through the flue and starts the heating furnace. The flue gas is circulated and heated and then enters the flue gas channel of the plate heat exchanger. At the same time, air enters the heat exchange medium channel of the plate heat exchanger. After the air is heated by the plate heat exchanger, it enters the ammonia evaporator together with the flue gas discharged from the flue gas channel of the plate heat exchanger to evaporate the ammonia. After the ammonia evaporates, the gas mixture is sprayed into the flue through the ammonia spray grid. The flue gas then enters the denitration reactor for denitration reaction, and after being cooled by the flue gas heat exchanger, it enters the induced draft fan to be discharged from the chimney.

[0022] After the startup phase, as the flue gas temperature rises, the CO removal reaction releases heat, and the heating furnace is shut down to save energy.

[0023] It can be seen from the above technical solutions that the embodiments of the present invention have at least the following advantages and positive effects:

[0024] In the plate heat exchanger of the embodiment of the present invention, the reaction surface is non-planar so that the reaction surface can generate turbulence to the flue gas flowing through the flue gas channel, aggravate the flue gas turbulence effect, ensure that the flue gas in the flue gas channel can fully contact with the catalyst, and make the reaction gas in the flue gas quickly catalytically burn in the catalyst micropores to release heat, thereby improving the catalytic reaction speed and reaction efficiency. At the same time, the catalytic reaction is located on the surface of the heat exchange plate, and the heat directly contacts the heat exchange plate to increase the wall temperature of the heat exchange plate, improve the heat exchange effect, and quickly transfer the waste heat to the heat exchange medium to achieve efficient waste heat recovery and utilization. At the same time, the reaction temperature can be controlled by adjusting the heat exchange medium, thereby improving the reaction efficiency and avoiding the problem of decreased reaction efficiency caused by high or low temperature.

[0025] The catalyst is directly attached to the heat exchange plate in the plate heat exchanger, integrating the catalyst and the plate heat exchanger structure, simplifying the system layout, reducing floor space and lowering construction cost investment. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Various objects, features and advantages of the present invention will become more apparent by considering the following detailed description of preferred embodiments of the present invention in conjunction with the accompanying drawings. The accompanying drawings are merely exemplary illustrations of the present invention and are not necessarily drawn to scale. In the accompanying drawings, the same reference numerals always represent the same or similar parts.

[0027] in:

[0028] Figure 1 is a schematic diagram of the internal structure of a plate heat exchanger according to an exemplary embodiment.

[0029] Figure 2 is a schematic structural diagram of a heat exchange plate assembly according to an exemplary embodiment.

[0030] Figure 3 The figure is a schematic diagram of a process flow of applying a plate heat exchanger to the removal of CO from the exhaust gas emitted by dry quenching of coke according to an exemplary embodiment.

[0031] Figure 4 It is a schematic diagram of a process flow of applying a plate heat exchanger to remove CO from sintering flue gas according to an exemplary embodiment.

[0032] The following are the descriptions of the reference numerals:

[0033] 1. Heat exchange plate assembly; 2. Heat exchange plate; 3. Sealing plate; 4. Heat exchange medium channel; 5. Flue gas channel; 6. Catalyst;

[0034] 101. Flue gas after CDQ desulfurization; 102. Heating furnace; 103. Primary plate heat exchanger; 104. Secondary plate heat exchanger; 105. Heat exchange medium.

[0035] 201. Flue gas after sintering and desulfurization; 202. Flue gas heat exchanger; 203. Heating furnace; 204. Plate heat exchanger; 205. Ammonia evaporator; 206. Ammonia injection grid; 207. Denitrification reactor; 208. Induced draft fan. DETAILED DESCRIPTION

[0036] Although the present invention can be easily embodied in different forms of embodiments, only some of the specific embodiments are shown in the drawings and will be described in detail in this specification. It should be understood that this description should be regarded as an exemplary illustration of the principles of the invention and is not intended to limit the invention to that described herein.

[0037] Thus, a feature indicated in this specification will be used to illustrate one of the features of an embodiment of the present invention, rather than implying that each embodiment of the present invention must have the described feature. In addition, it should be noted that this specification describes many features. Although some features can be combined together to illustrate possible system designs, these features can also be used in other combinations that are not explicitly described. Thus, unless otherwise stated, the described combinations are not intended to be limiting.

[0038] In the embodiments shown in the drawings, the indications of directions (such as up, down, left, right, front and back) used to explain the structure and movement of various elements of the present invention are not absolute but relative. These descriptions are appropriate when these elements are in the positions shown in the drawings. If the description of the positions of these elements changes, the indications of these directions also change accordingly.

[0039] See also Figure 1 and Figure 2 , Figure 1 is a schematic diagram of the internal structure of a plate heat exchanger according to an exemplary embodiment. Figure 2 is a schematic structural diagram of a heat exchange plate assembly 1 according to an exemplary embodiment.

[0040] A plate heat exchanger provided in one embodiment of the present invention includes multiple groups of heat exchange plate assemblies 1, each group of heat exchange plate assemblies 1 includes two heat exchange plates 2, a heat exchange medium channel 4 is provided between the two heat exchange plates 2, a flue gas channel 5 is provided between two adjacent groups of heat exchange plate assemblies 1, the heat exchange medium channel 4 and the flue gas channel 5 are arranged alternately, the surface of the heat exchange plate 2 facing the flue gas channel 5 is a reaction surface, the reaction surface is a non-planar surface so that the reaction surface can generate turbulence to the flue gas flowing through the flue gas channel 5, and a catalyst 6 is attached to the reaction surface.

[0041] Through the above structural design, the reaction surface is non-planar so that the reaction surface can generate turbulence to the flue gas flowing through the flue gas channel 5, aggravate the flue gas turbulence effect, ensure that the flue gas in the flue gas channel 5 can fully contact with the catalyst 6, so that the reaction gas in the flue gas can quickly catalytically burn in the micropores of the catalyst 6 to release heat, thereby improving the catalytic reaction speed and reaction efficiency. At the same time, the catalytic reaction is located on the surface of the heat exchange plate 2, and the heat directly contacts the heat exchange plate 2 to increase the wall temperature of the heat exchange plate 2, improve the heat exchange effect, and quickly transfer the waste heat to the heat exchange medium to achieve efficient waste heat recovery and utilization. At the same time, the reaction temperature can be controlled by adjusting the heat exchange medium, thereby improving the reaction efficiency and avoiding the problem of decreased reaction efficiency caused by high or low temperature.

[0042] The catalyst 6 is directly attached to the heat exchange plate 2 in the plate heat exchanger, integrating the catalyst 6 and the plate heat exchanger structure, simplifying the difficulty of system layout, reducing floor space and lowering construction cost investment.

[0043] exist Figure 1 In the embodiment shown, the flue gas flows from bottom to top, and the heat exchange medium moves from left to right. The alternating arrangement means that from front to back, there are the flue gas channel 5, the heat exchange medium channel 4, the flue gas channel 5, the heat exchange medium channel 4, and the flue gas channel 5, and so on. The number of the flue gas channels 5 and the heat exchange medium channels 4 can be adjusted as needed.

[0044] It is worth mentioning that compared with the solution of setting multiple straight heat exchange tubes, the plate heat exchanger with multiple heat exchange plates 2 has a smaller spacing between the heat exchange plates 2 and a larger spacing between the straight heat exchange tubes. Therefore, more heat exchange plates 2 can be arranged in a heat exchanger of the same volume, and correspondingly, the area in the heat exchanger to which the catalyst 6 can be attached is larger, which can improve the catalytic effect and catalytic efficiency of the heat exchanger, strengthen the CO catalytic combustion reaction, and improve the heat exchange effect.

[0045] The catalyst 6 may be one or more catalysts 6. In the present embodiment, the catalyst 6 is a carbon monoxide removal catalyst, which can catalyze the combustion of CO in the flue gas, generate heat while generating CO2. For example, under the high-temperature flue gas CO removal condition, the flue gas temperature reaches above 250°C, which can meet the temperature required by the carbon monoxide removal catalyst. With the different CO concentrations, the reaction exothermic temperature rise is about 20 to 100°C. The high-temperature flue gas contacts the heat exchange plate 2, and forms disordered turbulence under the action of the non-planar reaction surface, which promotes the flue gas to fully contact with the carbon monoxide removal catalyst on the surface of the heat exchange plate 2, and realizes an efficient carbon monoxide reaction. As the reaction proceeds, the heat accumulated inside the carbon monoxide removal catalyst is transferred to the heat exchange medium through the heat exchange plate 2. The heat exchange medium in the heat exchange medium channel 4 can be a gas or a liquid, such as air or other media as a heat exchange medium, which absorbs heat efficiently.

[0046] In other embodiments, the catalyst 6 may also be a denitration catalyst, etc.

[0047] The catalyst 6 is attached to the reaction surface by coating, dipping or spraying, ensuring that the catalyst 6 can be evenly attached to the reaction surface and is not easy to fall off from the reaction surface.

[0048] Each set of heat exchange plate assemblies 1 includes two sealing plates 3, which are respectively arranged at both ends of the heat exchange medium channel 4. The sealing plates 3 connect the two heat exchange plates 2 in each set of heat exchange plate assemblies 1, and the sealing plates 3 prevent the flue gas from entering the heat exchange medium channel 4. The heat exchange plates 2 and the sealing plates 3 separate the heat exchange medium and the flue gas into two independent areas.

[0049] As an embodiment in which the reaction surface is non-planar, the heat exchange plate 2 is wavy. The flue gas in the flue gas channel 5 passes through the wavy heat exchange plate 2 to generate a turbulent effect.

[0050] The wavy heat exchange plate 2 has alternately arranged crests and troughs, and the extension direction of each crest and each trough is the same as the direction from the inlet to the outlet of the smoke channel 5. This can not only produce turbulent effect on the smoke but also avoid causing great resistance to the flow of the smoke.

[0051] Of course, the extension direction of the trajectory of the wave crest and the extension direction of the trajectory of the wave trough may also form any angle with the direction from the inlet to the outlet of the smoke channel 5 .

[0052] As another embodiment in which the reaction surface is non-planar, the reaction surface has raised lines. The shape of the lines is not limited, and can be regular geometric shapes, such as rhombus, triangle, circle, etc., or irregular shapes.

[0053] The surface of the heat exchange plate 2 facing the heat exchange medium channel 4 is a non-reactive surface, and the non-reactive surface is a plane or a non-plane. When the non-reactive surface is a plane, the flow resistance to the heat exchange medium is small, and the heat exchange medium flows more smoothly and at a faster flow rate. When the non-reactive surface is a non-plane, the non-reactive surface can also cause the heat exchange medium to produce a turbulent effect, which is conducive to sufficient heat exchange between the heat exchange medium and the heat exchange plate 2.

[0054] It should be noted that, when the reaction surface is a non-planar surface, the non-reaction surface may be a planar surface or a non-planar surface.

[0055] There are two plate heat exchangers, namely the primary plate heat exchanger and the secondary plate heat exchanger, and the heat exchange medium channel 4 in the primary plate heat exchanger is connected with the heat exchange medium channel 4 in the secondary plate heat exchanger. Therefore, the high-temperature heat exchange medium in the secondary plate heat exchanger can be used to heat the heat exchange medium in the primary plate heat exchanger, and the waste heat is fully utilized to ensure the smooth progress of the catalytic reaction in the primary plate heat exchanger.

[0056] Specifically, under the condition of carbon monoxide removal from CDQ flue gas, the carbon monoxide concentration in the flue gas is high, which can reach 5-10% carbon monoxide concentration, but the flue gas temperature cannot meet the temperature above 250°C. If carbon monoxide removal is required, the temperature must be increased to meet the reaction temperature requirements. As the carbon monoxide reaction proceeds, the temperature will rise rapidly, and a heat exchanger is required to cool it down.

[0057] By setting up two plate heat exchangers, the first-stage heat exchanger can use the high-temperature heat exchange medium that absorbs heat inside the second-stage heat exchanger to enter the first-stage heat exchanger to increase the reaction temperature, so that the carbon monoxide removal catalyst in the first-stage heat exchanger is heated to complete the carbon monoxide catalytic combustion reaction, and then enters the second-stage heat exchanger for catalytic combustion reaction to release heat.

[0058] The heat exchange medium absorbs heat in the secondary heat exchanger and then releases heat in the primary heat exchanger. The heat exchange plate 2 adopts a corrugated structure to enhance the catalytic combustion reaction and heat transfer coefficient. The overall system is simple and stable in operation, and the investment is greatly reduced compared with the conventional solution of separately designing the catalyst 6 reactor and the two-stage heat exchanger.

[0059] like Figure 3 The figure shows the process flow chart of the present invention when it is applied to the removal of CO from the exhaust gas emitted by dry quenching.

[0060] The method for removing CO from the exhaust gas of coke dry quenching provided by the present invention comprises a heating furnace 102 and a plate heat exchanger of any of the above embodiments, and two plate heat exchangers are provided, namely a primary plate heat exchanger 103 and a secondary plate heat exchanger 104;

[0061] During the startup phase, the flue gas 101 after CDQ desulfurization enters the heating furnace 102 through the flue. The heating furnace 102 heats the flue gas temperature and the flue gas enters the flue gas channel of the primary plate heat exchanger 103. The flue gas undergoes a carbon monoxide removal reaction in the flue gas channel of the primary plate heat exchanger 103 and releases heat at the same time. The flue gas temperature is further increased. The flue gas then enters the flue gas channel of the secondary plate heat exchanger 104 to further remove CO and release heat. After the system temperature is increased, the heat exchange medium 105 is introduced into the heat exchange medium channel of the secondary plate heat exchanger 104. The heat exchange medium 105 first absorbs the heat of the flue gas in the flue gas channel of the secondary plate heat exchanger 104. The flue gas temperature decreases and the temperature of the heat exchange medium 105 increases. After the temperature is increased, the heat exchange medium 105 enters the heat exchange medium channel of the primary plate heat exchanger 103 and releases heat into the flue gas, thereby increasing the flue gas temperature and allowing the CO removal reaction to occur continuously.

[0062] After the start-up phase is over, the heating furnace is turned off, and the heat exchange medium in the heat exchange medium channel of the primary plate heat exchanger 103 is sent to the energy recovery system for heat utilization.

[0063] In a specific embodiment, the flue gas 101 after dry quenching and desulfurization generally contains 3-5% carbon monoxide gas, and its flue gas temperature is about 150-200°C, which is lower than the reaction temperature of the carbon monoxide catalyst of 250-400°C. In the startup stage, the flue gas 101 after dry quenching and desulfurization enters the heating furnace 102 through the flue, and the heating furnace 102 heats the flue gas temperature to 250°C, and then the flue gas enters the flue gas channel of the primary plate heat exchanger 103. The flue gas undergoes a carbon monoxide removal reaction in the flue gas channel of the primary plate heat exchanger 103 and releases heat at the same time, and the flue gas temperature is further increased, and then enters the flue gas channel of the secondary plate heat exchanger 104 for further carbon monoxide removal and heat release. After the system temperature is raised, the heat exchange medium 105 is introduced into the heat exchange medium channel of the secondary plate heat exchanger 104. The heat exchange medium 105 first absorbs the flue gas heat in the flue gas channel of the secondary plate heat exchanger 104, and the flue gas temperature is reduced by about 50-100°C, and the temperature of the heat exchange medium 105 is increased by about 250-300°C. After the temperature is raised, the heat exchange medium 105 enters the heat exchange medium channel of the primary plate heat exchanger 103 and releases heat into the flue gas, raising the flue gas temperature above 250°C, so that the CO removal reaction can continue to occur, and then the heating furnace 102 can be closed. Finally, the heat exchange medium can be further sent to the energy recovery system for heat utilization.

[0064] like Figure 4 The figure shows the process flow chart of the present invention when applied to CO removal from sintering flue gas.

[0065] The method for removing CO from sintering flue gas provided by the present invention comprises a flue gas heat exchanger 202, a heating furnace 203, a plate heat exchanger 204 of any of the above embodiments, an ammonia water generator 205, an ammonia injection grid 206, a denitration reactor 207 and an induced draft fan 208;

[0066] In the startup stage, the flue gas 201 after sintering and desulfurization enters the flue gas heat exchanger 202 through the flue and the heating furnace 203 is started. The flue gas is circulated and heated and then enters the flue gas channel of the plate heat exchanger 204. At the same time, air enters the heat exchange medium channel of the plate heat exchanger 204. After the air is heated by the plate heat exchanger 204, it enters the ammonia evaporator 205 together with the flue gas discharged from the flue gas channel of the plate heat exchanger 204 to evaporate the ammonia. After the ammonia evaporates, the gas mixture is sprayed into the flue through the ammonia spray grid 206. The flue gas then enters the denitration reactor 207 for denitration reaction, and after being cooled by the flue gas heat exchanger 202, it enters the induced draft fan 208 to be discharged from the chimney.

[0067] After the startup phase, as the flue gas temperature rises, the CO removal reaction releases heat, and the heating furnace 203 is turned off to save energy.

[0068] In a specific embodiment, the flue gas 201 after sintering desulfurization generally contains 5000-10000 ppm of carbon monoxide gas, and its flue gas temperature is about 80-100°C, which is lower than the reaction temperature of the carbon monoxide catalyst of 250-400°C. In the startup stage, the flue gas 201 after sintering desulfurization enters the flue gas heat exchanger 202 through the flue and starts the heating furnace 203 to heat the flue gas temperature to above 250°C. The flue gas then enters the flue gas channel of the plate heat exchanger 204, where the flue gas undergoes a carbon monoxide removal reaction and releases heat at the same time, and the flue gas temperature is increased. At the same time, air is passed into the heat exchange medium channel of the plate heat exchanger 204, and the air is heated to 200-250°C through the plate heat exchanger 204 and enters the ammonia evaporator 205 together with the flue gas discharged from the flue gas channel of the plate heat exchanger 204 to evaporate ammonia. After the ammonia evaporates, the gas mixture is sprayed into the flue through the ammonia spray grid 206. The flue gas then enters the denitration reactor 207 for denitration reaction, and after cooling down in the flue gas heat exchanger 202, enters the induced draft fan 208 and is discharged to the chimney. After the startup phase, as the flue gas temperature rises, the carbon monoxide removal reaction releases heat, and the heating furnace 203 is turned off to save energy.

[0069] Although the present invention has been described with reference to several typical embodiments, it should be understood that the terms used are illustrative and exemplary, rather than restrictive. Since the present invention can be embodied in a variety of forms without departing from the spirit or essence of the invention, it should be understood that the above embodiments are not limited to any of the foregoing details, but should be interpreted broadly within the spirit and scope defined by the appended claims, so all changes and modifications falling within the scope of the claims or their equivalents should be covered by the appended claims.

Claims

1. A plate heat exchanger, characterized in that: It comprises a plurality of groups of heat exchange plate assemblies, each group of the heat exchange plate assemblies comprises two heat exchange plates, a heat exchange medium channel is arranged between the two heat exchange plates, a flue gas channel is arranged between two adjacent groups of the heat exchange plate assemblies, the heat exchange medium channel and the flue gas channel are arranged alternately, the surface of the heat exchange plate facing the flue gas channel is a reaction surface, the reaction surface is a non-planar surface so that the reaction surface can generate turbulence to the flue gas flowing through the flue gas channel, and a catalyst is attached to the reaction surface.

2. The plate heat exchanger according to claim 1, characterized in that: The heat exchange plate is wavy.

3. The plate heat exchanger according to claim 2, characterized in that: The heat exchange plate has alternately arranged wave crests and wave troughs, and the extension direction of the trajectory of each wave crest and the extension direction of the trajectory of each wave trough are both the same as the direction from the inlet to the outlet of the flue gas channel.

4. The plate heat exchanger according to claim 1, characterized in that: Each group of the heat exchange plate assemblies includes two sealing plates, which are respectively arranged at both ends of the heat exchange medium channel. The sealing plates connect the two heat exchange plates in each group of the heat exchange plate assemblies, and the sealing plates prevent smoke from entering the heat exchange medium channel.

5. The plate heat exchanger according to claim 1, characterized in that: The plate heat exchangers are provided with two, namely a primary plate heat exchanger and a secondary plate heat exchanger, and the heat exchange medium channel of the primary plate heat exchanger is connected with the heat exchange medium channel of the secondary plate heat exchanger.

6. The plate heat exchanger according to claim 1, characterized in that: The reaction surface has raised textures.

7. The plate heat exchanger according to claim 1, characterized in that: The catalyst is a carbon monoxide removal catalyst and / or a denitration catalyst; The catalyst is attached to the reaction surface by coating, dipping or spraying.

8. The plate heat exchanger according to claim 1, characterized in that: The surface of the heat exchange plate facing the heat exchange medium channel is a non-reactive surface, and the non-reactive surface is a plane or a non-plane; The heat exchange medium in the heat exchange medium channel is gas or liquid.

9. A method for removing CO from tail gas emitted by dry quenching of coke, characterized in that: It comprises a heating furnace and the plate heat exchanger according to any one of claims 1 to 8, and the plate heat exchanger is provided with two, namely a primary plate heat exchanger and a secondary plate heat exchanger; In the startup stage, the flue gas after CDQ desulfurization enters the heating furnace through the flue, and the heating furnace heats the flue gas temperature and the flue gas enters the flue gas channel of the primary plate heat exchanger. The flue gas undergoes a carbon monoxide removal reaction in the flue gas channel of the primary plate heat exchanger and releases heat at the same time, and the flue gas temperature is further increased. The flue gas then enters the flue gas channel of the secondary plate heat exchanger to further remove CO and release heat. After the system temperature is increased, a heat exchange medium is introduced into the heat exchange medium channel of the secondary plate heat exchanger. The heat exchange medium first absorbs the heat of the flue gas in the flue gas channel of the secondary plate heat exchanger, and the flue gas temperature is reduced, while the heat exchange medium temperature is increased. After the temperature is increased, the heat exchange medium enters the heat exchange medium channel of the first-stage plate heat exchanger and releases heat into the flue gas, thereby increasing the flue gas temperature and allowing the CO removal reaction to occur continuously; After the startup phase is over, the heating furnace is turned off, and the heat exchange medium in the heat exchange medium channel of the primary plate heat exchanger is sent to the energy recovery system for heat utilization.

10. A method for removing CO from sintering flue gas, characterized in that: It comprises a flue gas heat exchanger, a heating furnace, a plate heat exchanger according to any one of claims 1 to 8, an ammonia water generator, an ammonia injection grid, a denitration reactor and an induced draft fan; In the startup stage, the flue gas after sintering and desulfurization enters the flue gas heat exchanger through the flue and starts the heating furnace. The flue gas is circulated and heated and then enters the flue gas channel of the plate heat exchanger. At the same time, air enters the heat exchange medium channel of the plate heat exchanger. After the air is heated by the plate heat exchanger, it enters the ammonia evaporator together with the flue gas discharged from the flue gas channel of the plate heat exchanger to evaporate the ammonia. After the ammonia evaporates, the gas mixture is sprayed into the flue through the ammonia spray grid. The flue gas then enters the denitration reactor for denitration reaction, and after being cooled by the flue gas heat exchanger, it enters the induced draft fan to be discharged from the chimney. After the startup phase, as the flue gas temperature rises, the CO removal reaction releases heat, and the heating furnace is shut down to save energy.

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