Recycling system and method for waste heat of dry quenching diffused flue gas

Abstract

The invention discloses a system and a method for recycling waste heat of dry quenching diffused flue gas. The recycling system is used for the dry quenching furnace system, the dry quenching furnace system comprises a dry quenching furnace and a dust removal device, and the recycling system comprises a combustion device, a heat exchanger and a heat exchanger, the first end of the first flue gas leading-in assembly is communicated with a dry quenching furnace fan rear diffused flue gas pipeline, and the second end of the first flue gas leading-in assembly is communicated with the flue gas inlet; the first end of the second flue gas leading-in assembly is communicated with the dry quenching furnace top diffused flue gas pipeline, and the second end of the second flue gas leading-in assembly is communicated with the flue gas inlet; and the flue gas leading-out assembly is used for communicating the flue gas outlet with the dust removal device. On one hand, air pollution and energy waste caused by emission of harmful flue gas into the atmosphere can be avoided, on the other hand, heat energy and chemical energy of combustible gas such as CO are recovered, and the operation safety of the dry quenching furnace system is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of recovery and utilization of dry coke quenching off-gas, and particularly relates to a system and method for recovering and utilizing the waste heat of dry coke quenching off-gas. Background Art

[0002] In the production of dry coke quenching, during the countercurrent physical heat exchange process between the cold circulating gas and the hot coke in the dry coke quenching furnace, there are also chemical reaction changes in the oxidation atmosphere of the high-temperature coke and the circulating gas. This reaction causes a small amount of coke burnout, generates combustible gas and mixes with the residual volatile components released from the red coke in the upper pre-storage chamber, resulting in a relatively increased concentration of combustible components in the circulating gas flowing out of the inclined air duct. When the concentration of combustible components exceeds the explosion limit, there is a risk of explosion. In addition, the CO content in the circulating gas commonly discharged through the discharge pipe after the fan is about 5%-10%, and the H 2 content is about 1%-3%. This part of the combustible gas is collected through the dust collection pipeline and enters the dry coke quenching environmental dust removal system. The gas after reaching the dust removal standard is discharged to the atmosphere. Not only is this part of the chemical heat energy not effectively utilized, resulting in energy waste, but also CO is a toxic and flammable gas, which will cause environmental pollution and has a certain degree of danger.

[0003] In the related art, the discharged off-gas is all discharged to the atmosphere after being treated, without effectively recovering the heat of the discharged off-gas itself and the chemical energy of the combustible gas, and also causing energy waste. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art or related technologies.

[0005] In view of this, the present invention provides a system and method for recovering and utilizing the waste heat of dry coke quenching off-gas. The recovery and utilization system can fully mix and burn the first off-gas in the discharge off-gas pipeline after the fan and the second off-gas in the discharge off-gas pipeline at the furnace top. After combustion, the high-temperature off-gas enters the dust removal device through the off-gas guiding assembly and is used for boiler heat supplement to improve the steam production rate. On the one hand, it can avoid the second off-gas being discharged into the atmosphere, causing energy waste and air pollution. On the other hand, it also recovers the heat energy and chemical energy of combustible gases such as CO in the discharge off-gas pipeline after the fan, and improves the operation safety of the dry coke quenching furnace system.

[0006] Specifically, it includes the following technical solutions:

[0007] In an embodiment of the first aspect of the present invention, a system for recovering and utilizing the waste heat of dry coke quenching off-gas is provided for a dry coke quenching furnace system. The dry coke quenching furnace system includes a dry coke quenching furnace and a dust removal device. The recovery and utilization system includes:

[0008] A combustion device, including a flue gas inlet and a flue gas outlet;

[0009] The first flue gas introduction component, the first end of the first flue gas introduction component is communicated with the post-discharge flue gas pipeline of the coke dry quenching fan, and the second end of the first flue gas introduction component is communicated with the flue gas inlet;

[0010] The second flue gas introduction component, the first end of the second flue gas introduction component is communicated with the top-discharge flue gas pipeline of the coke dry quenching furnace, and the second end of the second flue gas introduction component is communicated with the flue gas inlet;

[0011] The flue gas export component is used to communicate the flue gas outlet and the dust removal device.

[0012] Optionally, the recycling system further includes:

[0013] The nitrogen supplement component is used to communicate the flue gas export component and the nitrogen production station;

[0014] The nitrogen supplement component includes:

[0015] The nitrogen pipeline is used to communicate the export component and the nitrogen production station;

[0016] The pressure reducing valve group and the solenoid valve are arranged on the nitrogen pipeline.

[0017] Optionally, the first flue gas introduction component includes:

[0018] The first flue gas pipeline is used to communicate the flue gas inlet and the post-fan discharge flue gas pipeline;

[0019] The first switching valve is arranged on the first flue gas pipeline;

[0020] The booster fan is arranged on the first flue gas pipeline, and the booster fan is located on the first switching valve.

[0021] Optionally, the first flue gas introduction component further includes:

[0022] The first expansion joint is arranged on the first flue gas pipeline, and the first expansion joint is arranged close to the flue gas inlet;

[0023] The first monitoring device is arranged in the first flue gas pipeline, and the switching of the first switching valve is controlled according to the monitoring result of the first monitoring device.

[0024] Optionally, the second flue gas introduction component includes:

[0025] The second flue gas pipeline is used to communicate the flue gas inlet and the top-discharge flue gas pipeline;

[0026] The second switching valve is arranged on the second flue gas pipeline;

[0027] A check valve is provided on the second flue gas pipeline, and the check valve is located above the second switching valve;

[0028] A first heat preservation member is sleeved on the second flue gas pipeline.

[0029] Optionally, the second flue gas introduction assembly further includes:

[0030] A second expansion joint is provided on the second flue gas pipeline, and the second expansion joint is arranged near the flue gas inlet;

[0031] A second monitoring device is provided in the second flue gas pipeline, and the switching of the second switching valve is controlled according to the monitoring result of the second monitoring device.

[0032] Optionally, the combustion device includes: a combustion chamber; and

[0033] A first flue gas inlet and a second flue gas inlet are provided on the combustion chamber. The first flue gas inlet is connected to the first flue gas introduction assembly, and the second flue gas inlet is connected to the second flue gas introduction assembly;

[0034] A flame monitoring device is arranged at the first flue gas inlet and the second flue gas inlet;

[0035] A combustion-supporting pipeline is connected to the air inlet of the combustion device. A combustion-supporting fan is provided on the combustion-supporting pipeline, and the air inlet is arranged on the combustion chamber;

[0036] A pressure relief pipeline is provided on the combustion chamber, and a pressure relief valve is provided on the pressure relief pipeline.

[0037] Optionally, the combustion device further includes:

[0038] A dust discharging device is arranged below the combustion chamber. The dust discharging device is communicated with the combustion chamber, and the dust discharging device is arranged opposite to the pressure relief pipeline;

[0039] A level gauge is arranged in the dust discharging device.

[0040] Optionally, the flue gas export assembly includes:

[0041] A flue gas export pipeline for communicating the flue gas outlet and the dust removal device;

[0042] A third switching valve is arranged on the flue gas export pipeline;

[0043] A third expansion joint is arranged at one end of the flue gas export pipeline near the flue gas outlet;

[0044] A second heat preservation member is sleeved on the flue gas export pipeline;

[0045] A third monitoring device is arranged in the flue gas outlet pipeline, and the opening and closing of the nitrogen supplement component are controlled according to the monitoring results of the third monitoring device.

[0046] An embodiment of the second aspect of the present invention provides a method for recovering and utilizing the waste heat of the dry quenching coke discharge flue gas. Using the above-mentioned recovery and utilization system, the recovery and utilization method includes:

[0047] Collect the first flue gas in the discharge flue gas pipeline after the fan, and at the same time collect the second flue gas in the discharge flue gas pipeline at the top of the furnace.

[0048] Mix and burn the first flue gas and the second flue gas to form combustion ash and combustion gas.

[0049] The combustion ash is discharged, and after the burner enters the dust removal device, it participates in the boiler combustion.

[0050] The waste heat recovery and utilization system and method for the dry quenching coke discharge flue gas provided by the embodiments of the present invention. Among them, the waste heat recovery and utilization system for the dry quenching coke discharge flue gas includes a combustion device, and the combustion device is provided with a flue gas inlet and a flue gas outlet. The first flue gas introduction component is used to connect the discharge flue gas pipeline after the dry quenching furnace fan and the combustion device, and the second flue gas introduction component is used to connect the discharge flue gas pipeline at the top of the dry quenching furnace and the combustion device. In this way, the first flue gas in the discharge flue gas pipeline after the fan and the second flue gas in the discharge flue gas pipeline at the top of the furnace can be mixed and fully burned. On the one hand, introducing the second flue gas into the combustion device greatly reduces the combustible gas components entering the circulating gas, effectively reducing the risk of high combustible gas components in the circulating gas. At the same time, after reducing the combustible gas components in the gas circulation system, the air intake of the dry quenching coke can be reduced, and the combustion of combustible gas in the annular air duct of the dry quenching furnace can be reduced. At this time, the burnout amount of coke powder can be reduced; on the other hand, it can also make part of the circulating gas pass through the coke layer in the pre-storage chamber, which plays a very good role in improving the air volume distribution in the dry quenching furnace and the pre-cooling of coke. It can make the heat exchange between the circulating gas and coke in the dry quenching furnace more uniform and reduce the coke discharge temperature. The high-temperature gas after combustion enters the dust removal device through the flue gas export component and then enters the boiler to supplement heat to the boiler to increase the steam production rate and improve the energy utilization rate.

[0051] The above description is only an overview of the technical solution of this application. In order to be able to understand the technical means of this application more clearly, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features and advantages of this application more obvious and understandable, the specific embodiments of this application are specifically described below. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] To more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0053] Figure 1 Schematic diagram of the position of the recycling system in the coke dry quenching system according to an embodiment of the present invention;

[0054] Figure 2 Schematic diagram of the recycling system according to an embodiment of the present invention;

[0055] Figure 3 For Figure 2 Schematic diagram of A-A of the shown alternative embodiment.

[0056] Wherein, Figures 1 to 3 The corresponding relationship between the reference numerals and the component names in the drawings is as follows:

[0057] 100 Recycling system, 110 First flue gas introduction component, 111 First switching valve, 112 Booster fan, 113 First expansion joint, 114 First monitoring device, 115 First flue gas pipeline, 116 Scrubber for discharged flue gas, 120 Second flue gas introduction component, 121 Second switching valve, 122 Second expansion joint, 123 First heat preservation member, 124 Second monitoring device, 125 Check valve, 126 Second flue gas pipeline, 130 Combustion device, 131 First flue gas inlet, 132 Second flue gas inlet, 133 Air inlet, 134 Combustion-supporting fan, 135 Explosion relief pipeline, 136 Explosion relief valve, 137 Level gauge, 138 Dust discharge device, 139 Flame monitoring device, 140 Flue gas export component, 141 Third expansion joint, 142 Third switching valve, 143 Second heat preservation member, 144 Flue gas export pipeline, 150 Nitrogen supplement component, 151 Nitrogen pipeline, 152 Pressure reducing valve group and solenoid valve, 200 Coke dry quenching system, 210 Coke dry quenching furnace, 211 Pre-storage chamber, 212 Inclined flue area, 213 Cooling chamber, 220 Primary dust collector, 230 Boiler, 240 Secondary dust collector, 250 Circulation fan, 260 Sub-economizer, 270 First top discharged flue gas pipeline, 280 Second top discharged flue gas pipeline, 290 Discharged flue gas pipeline after the fan. Detailed implementation manners

[0058] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0059] Before further describing the embodiments of the present invention in detail, the directional terms involved in the embodiments of the present invention, such as "upper part", "lower part", and "side part", do not have the meaning of limiting the protection scope of the present invention.

[0060] To make the technical solutions and advantages of the present invention clearer, the embodiments of the present invention will be further described in detail below in conjunction with the accompanying drawings.

[0061] Figure 1 Schematic diagram of the position of the recycling system in the coke dry quenching system according to an embodiment of the present invention; Figure 2 Schematic diagram of the recycling system according to an embodiment of the present invention; Figure 3 For Figure 2 Schematic diagram of A-A of the shown alternative embodiment.

[0062] As Figures 1 to 3 As shown, an embodiment of the present invention provides a recycling system 100 for the waste heat of the coke dry quenching off-gas, which is used for the coke dry quenching system 200. The coke dry quenching system 200 includes a coke dry quenching furnace 210 and a dust removal device. The recycling system 100 includes:

[0063] A combustion device 130, including a flue gas inlet and a flue gas outlet;

[0064] A first flue gas introduction assembly 110, the first end of the first flue gas introduction assembly 110 is connected to the off-gas pipeline 290 after the coke dry quenching fan, and the second end of the first flue gas introduction assembly 110 is connected to the flue gas inlet;

[0065] A second flue gas introduction assembly 120, the first end of the second flue gas introduction assembly 120 is connected to the off-gas pipeline at the top of the coke dry quenching furnace, and the second end of the second flue gas introduction assembly 120 is connected to the flue gas inlet;

[0066] A flue gas export assembly 140 for connecting the flue gas outlet and the dust removal device.

[0067] Among them, the recovery and utilization system 100 for the waste heat of the dry quenching coke off-gas includes a combustion device 130, which is provided with a flue gas inlet and a flue gas outlet. The first flue gas introduction component 110 is used to connect the off-gas pipeline 290 after the dry quenching furnace fan and the combustion device 130, and the second flue gas introduction component 120 is used to connect the off-gas pipeline at the top of the dry quenching furnace and the combustion device 130. In this way, the first flue gas in the off-gas pipeline 290 after the fan and the second flue gas in the off-gas pipeline at the top of the furnace can be mixed and fully burned. On the one hand, introducing the second flue gas into the combustion device 130 greatly reduces the combustible gas components entering the circulating gas, effectively reducing the risk of high combustible gas components in the circulating gas. At the same time, after reducing the combustible gas components in the gas circulation system, the air intake amount of the dry quenching coke can be reduced, and the combustion of combustible gas in the annular air duct of the dry quenching furnace can be reduced. At this time, the burnout amount of coke powder can be reduced; on the other hand, it can also make part of the circulating gas pass through the coke bed in the pre-storage chamber, which plays a very good role in improving the air volume distribution and coke pre-cooling in the dry quenching furnace 210, making the heat exchange between the circulating gas and the coke in the dry quenching furnace 210 more uniform and reducing the coke discharging temperature. The high-temperature gas after combustion enters the dust removal device through the flue gas export component 140 and then enters the boiler 230 to supplement heat for the boiler 230 to increase the steam production rate and improve the energy utilization rate.

[0068] Specifically, as Figure 1 shown, those skilled in the art are well aware that the dry quenching furnace system 200 includes a dry quenching furnace 210, a primary dust collector 220, a boiler 230, a secondary dust collector 240, a circulating fan 250, and a secondary economizer 260 arranged in sequence. The dry quenching furnace 210 includes a pre-storage chamber 211, an inclined channel area 212, and a cooling chamber 213 arranged from top to bottom. The flue gas passing through the inclined channel area 212 enters the primary dust collector 220 and then enters the boiler 230 to heat the boiler. Then, the gas coming out of the boiler 230 passes through the secondary dust collector 240 and returns to the cooling chamber to form a gas cycle. In dry quenching coke production, in order to ensure the pressure balance of the dry quenching furnace system 200 and ensure the negative pressure of the pre-storage chamber 211 at the top of the dry quenching furnace 210 during coke charging, an off-gas pipeline 290 after the circulating fan 250 needs to be set. This pipeline is normally in an open state during normal production to discharge the excess circulating gas and maintain the stability of the pressure at the top of the dry quenching furnace 210. According to the data obtained from the detection of combustible gases in the circulating gas during dry quenching coke production, the CO content in the circulating gas discharged from the off-gas pipeline 290 after the fan is about 5%-10%, H 2The content is about 1%-3%. This part of the combustible gas is collected through the dust collection pipeline and then enters the dry coke quenching environmental dust removal system. The gas after reaching the dust removal standard is discharged into the atmosphere. Not only is this part of the chemical heat energy not effectively utilized, resulting in energy waste, but also CO is a toxic and flammable gas, which will cause environmental pollution and has certain dangerous properties. At the same time, for the safety of the dry coke quenching system 200, when the dry coke quenching furnace 210 shuts down in an accident state, the flue gas discharge pipeline on the top of the furnace needs to be opened to urgently discharge the circulating gas. The flue gas discharge pipeline on the top of the dry coke quenching furnace 210 is concentrated in the closed space at the top of the pre-storage chamber 211 of the dry coke quenching furnace 210. The composition is close to coke oven gas and contains a large amount of CO, H 2 and other combustible gas components, and the discharge temperature is relatively high, about 900-960°C, and it is extremely easy to burn when encountering air, so it is rarely opened during normal production.

[0069] Considering the above situation of the dry coke quenching system 200, the present application further utilizes the chemical energy and its own heat energy of the combustible gas contained in the second flue gas in the flue gas discharge pipeline on the top of the furnace. First, it can effectively recover energy. Second, it can also reduce the combustible gas components entering the dry coke quenching system 100, reduce the air intake, and reduce the burning loss rate of dry coke quenching. Third, it increases the air permeability of the coke in the pre-storage section 211 inside the dry coke quenching furnace 210, enabling the coke and the circulating gas in the dry coke quenching furnace 210 to exchange heat better. Therefore, the second flue gas in the flue gas discharge pipeline on the top of the furnace and the first flue gas in the flue gas discharge pipeline 290 after the fan are simultaneously collected into the combustion device 130, and the CO, H 2 and other combustible gases are burned. The high-temperature flue gas after combustion enters the primary dust collector 220 inside the dust removal device through the pipeline and enters the boiler 230 together with the circulating gas to generate steam, playing a role in supplementary heating. The recovery and utilization system 100 of the present application not only reduces the emission of combustible gases in the discharged flue gas, recovers heat and increases the steam production rate, but also reduces the combustible gas components in the dry coke quenching system 100 and reduces the burning loss rate. At the same time, the recovery and utilization system 100 has a simple setting, flexible layout, and simple operation, reduces the burning loss rate of the dry coke quenching system 200, and improves the air permeability and effective heat exchange between the circulating gas and the coke in the pre-storage chamber 211, thus effectively ensuring the energy conservation, environmental protection, high efficiency and stability of the dry coke quenching system 200.

[0070] In a feasible implementation manner, the recovery and utilization system 100 further includes:

[0071] A nitrogen supplement component 150, used to connect the flue gas export component 140 and the nitrogen production station;

[0072] The nitrogen supplement component 150 includes:

[0073] A nitrogen pipeline 151, used to connect the flue gas export component 140 and the nitrogen production station;

[0074] A pressure reducing valve group and a solenoid valve 152 are arranged on the nitrogen pipeline 151.

[0075] Among them, as Figure 2 shown, since the final flue gas outlet assembly 140 finally enters the boiler 230 after passing through the dust removal device to supplement heat to the boiler 230 and improve the steam production rate of the boiler 230. However, the maximum flue gas temperature that the boiler 230 can withstand is below 960 °C. When the temperature of the high-temperature flue gas after the mixed combustion of the first flue gas and the second flue gas in the combustion device 130 is greater than 960 °C, the high-temperature flue gas is cooled by supplementing nitrogen, and the nitrogen enters the flue gas outlet assembly 140 through the nitrogen supplement assembly 150.

[0076] Specifically, the nitrogen supplement assembly 150 includes a nitrogen pipeline 151 and a pressure reducing valve group and a solenoid valve assembly 152 arranged on the nitrogen pipeline 151. Nitrogen is supplied by the on-site nitrogen production station. After passing through the pressure reducing valve group and the solenoid valve 152, it is reduced to a certain pressure and then enters the flue gas outlet assembly 140 to cool the high-temperature flue gas. When the temperature of the high-temperature flue gas is greater than or equal to 960 °C, the pressure reducing valve group and the solenoid valve 152 are opened; when the temperature of the high-temperature flue gas is less than 960 °C, the pressure reducing valve group and the solenoid valve 152 are closed.

[0077] In a feasible implementation manner, the first flue gas introduction assembly 110 includes:

[0078] A first flue gas pipeline 115 for connecting the flue gas inlet and the flue gas pipeline 290 for discharging after the fan;

[0079] A first switching valve 111 arranged on the first flue gas pipeline 115;

[0080] A pressurizing fan 112 arranged on the first flue gas pipeline 115, and the pressurizing fan 112 is located on the first switching valve 111.

[0081] Among them, as Figure 2 shown, the first flue gas assembly 110 includes a first flue gas pipeline 115, a first switching valve 111 and a pressurizing fan 112 arranged on the first flue gas pipeline 115. The first flue gas of the flue gas pipeline 290 for discharging after the fan is discharged to the atmosphere, and the discharged first flue gas is collected by the discharged flue gas dust collection hood 116. After the discharged flue gas dust collection hood 116 collects the first flue gas and air, it is divided into two paths. The first path is connected to the first dust collector 220 of the coke dry quenching system 200, and the second path is connected to the combustion device 130 of the present application. After sufficient combustion, heat is supplemented to the boiler 230 of the coke dry quenching system 200.

[0082] It should be noted that the two pipelines are controlled by the first switching valve 111. When combustion heat supplement is required, the pipeline valve of the second path is opened, and the pipeline valve of the first path is closed at the same time; when the recycling system 100 needs maintenance and repair, the pipeline valve of the second path is closed, and the pipeline valve of the first path is opened at the same time. In this way, the first flue gas in the post-fan discharge flue gas pipeline 290 directly enters the first dust collector 220, that is, the first path and the second path are controlled to be opened or closed by the first switching valve 111. The first switching valve 111 is a manual and automatic integrated quick cut-off valve and can realize remote control.

[0083] In order to ensure the pressure of the first flue gas and air entering the combustion device 130, avoid the backflow of the flue gas after combustion, and control the intake of air at the same time, a pressurizing fan 112 is arranged behind the first switching valve 111. That is to say, the first flue gas and air are pressurized by the pressurizing fan 112 and then sent into the combustion device 130, which can ensure the gas pressure entering the combustion device 130, avoid the backflow of the combustion flue gas at the same time, and ensure the operation reliability of the recycling system 100.

[0084] In a feasible implementation manner, the first flue gas introduction assembly 110 further includes:

[0085] A first expansion joint 113 is arranged on the first flue gas pipeline 115, and the first expansion joint 113 is arranged close to the flue gas inlet;

[0086] A first monitoring device 114 is arranged in the first flue gas pipeline 115, and the switching of the first switching valve 111 is controlled according to the monitoring result of the first monitoring device 114.

[0087] Among them, in order to ensure the sufficiency of combustion, a first monitoring device 114 is arranged in the first flue gas pipeline 115, and the first monitoring device 114 includes pressure, temperature and flow monitoring sensors. It can be understood that the pressure, temperature and flow monitoring are to ensure the stability of the flue gas entering the combustion device 130. That is to say, if the pressure, flow and / or temperature of the flue gas change, it is necessary to timely judge the problems occurring in the recycling system 100, and cut off the valve in case of emergency to avoid the backflow problem of the flue gas in the combustion device 130.

[0088] It should be noted that generally, the temperature of the first flue gas in the post-fan discharge flue gas pipeline 290 is about 100-130 °C. Arranging the first expansion joint 113 on the first flue gas pipeline 115 can absorb the thermal expansion and contraction generated when the temperature of the first flue gas pipeline 115 changes, extend the service life of the first flue gas pipeline 115, ensure the safety and stability of the use of the first flue gas pipeline 115, and improve the reliability of the recycling system 100.

[0089] In a feasible implementation manner, the second flue gas introduction assembly 120 includes:

[0090] A second flue gas pipeline 126 for connecting the flue gas inlet and the top discharge flue gas pipeline of the furnace;

[0091] A second switching valve 121 provided on the second flue gas pipeline 126;

[0092] A check valve 125 provided on the second flue gas pipeline 126, and the check valve 125 is located above the second switching valve 121;

[0093] A first heat preservation member 123 sleeved outside the second flue gas pipeline 126.

[0094] Among them, as Figure 2 shown, the second flue gas introduction assembly 120 includes a second flue gas pipeline 126, and a second switching valve 121 and a check valve 125 provided on the second flue gas pipeline 126. The original dry quenching furnace system 200 has already been provided with a first top discharge flue gas pipeline 270. At this time, a second top discharge flue gas pipeline 280 is further provided on the top of the dry quenching furnace. The combustion device 130 of the present application is connected to the second top discharge flue gas pipeline 280. When combustion heat supplement is carried out, the valve of the second top discharge flue gas pipeline 280 is opened. Since the pre-storage chamber 211 of the dry quenching furnace 210 is in a positive pressure state, the high-temperature combustible second flue gas enters the combustion device 130 through the second flue gas pipeline 126 and mixes and burns with the first flue gas and air entering the combustion device 130, thus reducing the content of CO and H 2 in the combustible gas content in the flue gas. At the same time, the heat energy and chemical energy after the combustion of the combustible gas are recovered, and the operation safety of the dry quenching furnace system 200 is improved.

[0095] It should be noted that since the temperature of the second flue gas in the top discharge flue gas pipeline can reach 900 - 960 °C, a first heat preservation member 123 needs to be provided outside the second flue gas pipeline 126. Setting the first heat preservation member 123 on the high-temperature second flue gas pipeline 126 can, on the one hand, reduce heat loss and energy consumption; on the other hand, it can also prevent damage to the second flue gas pipeline 126. Since condensation will occur on the second flue gas pipeline 126 due to too high temperature, corroding the second flue gas pipeline 126, the first heat preservation member 123 can avoid the condensation phenomenon of the second flue gas pipeline 126 and improve the service life and use safety of the second flue gas pipeline 126. The first heat preservation member 123 is heat preservation cotton, polyurethane foam plastic or rubber and plastic heat preservation layer material. Usually, the thickness of the first heat preservation member 123 is 100 mm to 200 mm.

[0096] It can be understood that when the recycling system 100 fails or other emergencies occur, while closing the valve of the second top discharge flue gas pipeline 280, the valve of the first top discharge flue gas pipeline 270 is opened, that is, the opening and closing of the second switching valve 121 are controlled. At the same time, in order to prevent the reverse flow of flue gas caused by the flue gas pressure problem, a check valve 125 is provided on the second flue gas pipeline 126, that is, the flue gas can only enter the combustion device 130, and the flue gas in the combustion device 130 will not flow back into the second top discharge flue gas pipeline 280. It should be noted that the first flue gas pipeline 115 is for positive pressure discharge, and the discharge pressure can reach 2 KPa to 7 KPa, and the pressure is greater than the pressure in the combustion device 130. Therefore, a check valve is usually not required. However, considering the possible explosion risk of the combustion device 130, a check valve can also be provided on the first flue gas pipeline 115 to ensure the safety of the recycling system 100 during use.

[0097] In a feasible implementation manner, the second flue gas introduction assembly 120 further includes:

[0098] A second expansion joint 122, which is arranged on the second flue gas pipeline 126, and the second expansion joint 122 is arranged close to the flue gas inlet;

[0099] A second monitoring device 124, which is arranged in the second flue gas pipeline 126, and the switching of the second switching valve 121 is controlled according to the monitoring results of the second monitoring device 124.

[0100] Among them, in order to prevent the high-temperature expansion of the second flue gas pipeline 126, a second expansion joint 122 is arranged on the second flue gas pipeline 126, which can absorb the thermal expansion and contraction generated when the temperature of the second flue gas pipeline 126 changes, extend the service life of the second flue gas pipeline 126, and at the same time can also ensure the safety and stability of the use of the second flue gas pipeline 126, thereby improving the reliability of the recycling system 100.

[0101] It should be noted that in order to ensure the sufficiency of combustion, a second monitoring device 124 is arranged in the second flue gas pipeline 126. The second monitoring device 124 includes pressure, temperature and flow monitoring sensors. Similarly, monitoring the pressure, temperature and flow of the flue gas in the second flue gas pipeline can ensure the stability of the flue gas entering the combustion device 130. If the pressure, temperature and / or flow of the flue gas change, it is necessary to timely judge the problems occurring in the recycling system 100, and cut off the valve in case of emergency to avoid the backflow of the flue gas in the combustion device.

[0102] In a feasible implementation manner, the combustion device 130 includes: a combustion chamber; and

[0103] The first flue gas inlet 131 and the second flue gas inlet 132 are arranged on the combustion chamber. The first flue gas inlet 131 is connected to the first flue gas introduction assembly 110, and the second flue gas inlet 132 is connected to the second flue gas introduction assembly 120;

[0104] The flame monitoring device 139 is arranged at the first flue gas inlet 131 and the second flue gas inlet 132;

[0105] The combustion-supporting pipeline is connected to the air inlet 133 of the combustion device 130. A combustion-supporting fan 134 is arranged on the combustion-supporting pipeline, and the air inlet 133 is arranged on the combustion chamber;

[0106] The explosion relief pipeline 135 is arranged on the combustion chamber, and an explosion relief valve 136 is arranged on the explosion relief pipeline 135.

[0107] Among them, as Figure 2 and Figure 3 shown, the combustion device 130 includes a first flue gas inlet 131 for communicating with the first flue gas pipeline 115, and a second flue gas inlet 132 for communicating with the second flue gas pipeline 126. The first flue gas and air in the flue gas pipeline 290 behind the fan enter the combustion chamber through the first flue gas pipeline 115 and the first flue gas inlet 131. The second flue gas in the second roof flue gas pipeline 280 enters the combustion chamber through the second flue gas pipeline 126 and the second flue gas inlet 132. The first flue gas, the second flue gas and the air are mixed and burned. When the combustible gas component in the combustion device 130 is relatively high but the air content is insufficient, air can be introduced through the combustion-supporting fan 134 and the combustion-supporting pipeline for combustion support to ensure the full combustion of the combustible gas. The motor supporting the combustion-supporting fan 134 is controlled by a frequency converter, and the air volume entering the combustion device 130 can be controlled.

[0108] It should be noted that in order to ensure the stability of the flame at the first flue gas inlet 131 and the second flue gas inlet 132, a flame monitoring device 139 is arranged at the first flue gas inlet 131 and the second flue gas inlet 132. The flame detection device can detect the length of the flame, and the flow rates of the first flue gas and the second flue gas are controlled by controlling the opening degree of the intake valve to keep the flame at a uniform level to ensure the stability of the flame.

[0109] It can be understood that a pressure sensor can be provided inside the combustion device 130. When the pressure inside the combustion device 130 is too high or a flash explosion occurs, the valves of the first flue gas pipeline 115 and the second flue gas pipeline 126 are closed, and the explosion relief valve 136 on the explosion relief pipeline 135 of the combustion device is opened to timely discharge the excess flue gas inside the combustion device 130. That is to say, the first switching valve 111 and the second switching valve 121 switch to other pipelines, closing the first flue gas pipeline 115 and the second flue gas pipeline 126, which has been described above and will not be elaborated here. Among them, when the pressure in the combustion device 130 increases sharply, it is determined that a flash explosion occurs inside the combustion device 130.

[0110] In a feasible implementation manner, the combustion device 130 further includes:

[0111] A dust discharge device 138, arranged below the combustion chamber, the dust discharge device 138 is communicated with the combustion chamber, and the dust discharge device 138 is arranged opposite to the explosion relief pipeline 135;

[0112] A level gauge 137, arranged inside the dust discharge device 138.

[0113] Among them, part of the coke powder is carried in the flue gas entering the first flue gas pipeline 115 and the second flue gas pipeline 126. When the flue gas burns inside the combustion device 130, this part of the coke powder is burned together. To prevent the burned dust from clogging the combustion device 130, a dust discharge device 138 is arranged at the bottom of the combustion device 130. The dust discharge device 138 is controlled by a discharge pipeline and a valve, and a level gauge 137 is arranged inside the dust discharge device 138. When the level gauge 137 monitors that the dust reaches a high level, the valve of the dust discharge device 138 is opened, and the dust is discharged and then transported away by a vehicle for external treatment.

[0114] In a feasible implementation manner, the flue gas export assembly 140 includes:

[0115] A flue gas export pipeline 144, used to connect the flue gas outlet and the dust removal device;

[0116] A third switching valve 142, arranged on the flue gas export pipeline 144;

[0117] A third expansion joint 141, arranged at one end of the flue gas export pipeline 144 close to the flue gas outlet;

[0118] A second heat preservation member 143, sleeved outside the flue gas export pipeline 144;

[0119] A third monitoring device, arranged inside the flue gas export pipeline 144, and the opening and closing of the nitrogen supplement assembly 150 are controlled by the monitoring results of the third monitoring device.

[0120] Among them, in the normal coke dry quenching system, the off-gas is directly discharged into the atmosphere after being purified by environmental dust removal. In this application, after the flue gas containing combustible gas components and high temperature is recovered and burned, the burned flue gas with relatively high heat quality is introduced into the front of the boiler 230 again, and after being mixed with the circulating flue gas during normal production, it enters the boiler 230. The introduction position of the burned flue gas is selected at the manhole of the primary dust collector 220 between the boiler 230 and the coke dry quenching furnace 210. That is to say, when the combustion of the mixed flue gas is completed in the combustion device 130, the generated high-temperature flue gas enters the vertical wall reserved holes on both sides of the primary dust collector 220 and the coke dry quenching furnace 210 side through the flue gas export assembly 140, and is mixed with the circulating gas after heat exchange at the outlet of the coke dry quenching furnace 210, and then enters the primary dust collector 220 together, and then enters the boiler 230 together to exchange heat to generate steam. Since the temperature of the flue gas after combustion in the combustion device 130 is relatively high, a second heat preservation member 143 needs to be arranged outside the flue gas export pipeline 144. By arranging the second heat preservation member 143 on the high-temperature flue gas export pipeline 144, on the one hand, heat loss can be reduced and energy consumption can be lowered; on the other hand, it can also prevent the damage of the flue gas export pipeline 144. Because condensation will occur on the flue gas export pipeline 144 due to too high temperature, corroding the flue gas export pipeline 144, the second heat preservation member 143 can avoid the condensation phenomenon of the flue gas export pipeline 144, and improve the service life and use safety of the flue gas export pipeline 144. The second heat preservation member 143 is heat preservation cotton, polyurethane foam plastic or rubber and plastic heat preservation layer material. Usually, the thickness of the second heat preservation member 143 is 100 mm to 200 mm. It can be understood that the first heat preservation member 123 is sleeved outside the entire second flue gas pipeline 126, and the second heat preservation member 143 is sleeved outside the entire flue gas export pipeline 144, so as to protect the entire second flue gas pipeline 126 and the flue gas export pipeline 144. The attached drawing is a partial sectional view, so only a part of the first heat preservation member 123 and a part of the second heat preservation member 143 are shown.

[0121] It should be noted that in case of a coke dry quenching accident or when the combustion device 130 fails to start, the third pipe-cutting valve 142 is closed to cut off the connection with the coke dry quenching system 200, preventing the high-temperature circulating gas from flowing back into the combustion device 130 from the primary dust collector 220. Since the inside of the primary dust collector 220 is under negative pressure, there is no need to set a pressurizing device for the flue gas export assembly 140.

[0122] Since the maximum high-temperature flue gas temperature that the boiler 230 can withstand is below 960°C, when the high-temperature flue gas temperature after combustion in the combustion device 130 is greater than or equal to 960°C, the pressure reducing valve group and the solenoid valve 150 of the nitrogen supplement component 150 need to be opened, and the high-temperature flue gas in the flue gas outlet pipe 144 is cooled by supplementing nitrogen. When the temperature is less than 960°C, the pressure reducing valve group and the solenoid valve 152 are closed, and nitrogen no longer enters the flue gas outlet pipe 144. It can be understood that nitrogen is an inert gas, and it is well known in the art that the main component of the circulating flue gas in the coke dry quenching furnace is also nitrogen. If air or CO2 is used as the cooling gas, it will chemically react with the incandescent coke in the coke dry quenching furnace, affecting the normal operation of the coke dry quenching furnace. Therefore, nitrogen can only be selected as the cooling gas.

[0123] It can be understood that since there is high-temperature flue gas in the flue gas outlet pipe 144, which is a high-temperature pipe, a third expansion joint 141 is provided on the flue gas outlet pipe 144. The principle is the same as that of the first expansion joint 113 and the second expansion joint 122, and will not be elaborated here.

[0124] It should be noted that the recovery and utilization system 100 of the present application adopts an interlocking control system to control each valve and monitoring device, which can ensure the combustion in the combustion device 130 under normal production conditions, and ensure the discharge of flue gas in the combustion device 130 and the switching of pipelines under abnormal conditions. This interlocking control system is interlocked with the main control system of the normal operation of the coke dry quenching furnace system 200, and controls the flow rate of combustion-supporting air entering the combustion device 130 through the combustible gas components and oxygen content in the flue gas.

[0125] Another embodiment of the present invention provides a method for recovering and utilizing the waste heat of the coke dry quenching flue gas. Using the above-mentioned recovery and utilization system 100, the recovery and utilization method includes:

[0126] Collect the first flue gas in the flue gas discharge pipe after the fan, and at the same time collect the second flue gas in the flue gas discharge pipe at the furnace top;

[0127] Mix and burn the first flue gas and the second flue gas to form combustion ash and combustion gas;

[0128] The combustion ash is discharged, and after entering the dust removal device, the burner participates in the boiler combustion.

[0129] Among them, the first flue gas in the flue gas discharge pipe 290 after the fan is collected through the first flue gas introduction component 110, and air is introduced. At the same time, the second flue gas in the second furnace top flue gas discharge pipe 280 is collected through the second flue gas introduction component 120. The first flue gas, the second flue gas and air enter the combustion device 130 at the same time for mixing combustion. The generated combustion ash is discharged outside the combustion device 130, and the generated high-temperature gas enters the boiler 230 through the first dust collector 220 to participate in the heat supplement of the boiler 230, so as to improve the gas production rate of the boiler 230.

[0130] It should be noted that the recycling method of this application can reduce the combustible gas components in the coke dry quenching system 200, which means that most of the combustible gases in the circulating gas in the coke dry quenching furnace 210 are volatilized from the red-hot coke in the pre-storage chamber 211 and then enter the gas circulation system through the coke layer. Therefore, this application burns the second flue gas introduced from the second top discharge flue gas pipeline 280 of the coke dry quenching furnace in the combustion device 130, greatly reducing the combustible gas components entering the circulating gas and effectively reducing the risk of high combustible gas components in the circulating gas.

[0131] After reducing the combustible gas components in the circulating gas, the air intake for coke dry quenching can be reduced, and the combustion of combustible gases in the annular air duct of the coke dry quenching furnace 210 can be reduced. At this time, the burnout amount (burnout rate) of coke powder can be reduced, and the coke powder can be collected after being dusted by the primary dust collector 220 or the secondary dust collector 240.

[0132] The second top discharge flue gas pipeline 280 is in an open state, which allows part of the circulating gas to pass through the coke layer in the pre-storage chamber 211, plays a very good role in improving the air volume distribution in the coke dry quenching furnace 210 and the pre-cooling of coke, enables the heat exchange between the circulating gas and the coke in the coke dry quenching furnace 210 to be more uniform, and reduces the coke discharging temperature.

[0133] It can be understood that since the recycling method of this application is completed by the recycling system 100, the recycling method has all the advantages of the above-mentioned recycling system 100 and will not be elaborated here.

[0134] In the present invention, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance. The term "plural" means two or more unless otherwise clearly defined.

[0135] After considering the specification and practicing the present invention disclosed herein, those skilled in the art will readily think of other embodiments of the present invention. The present invention is intended to cover any variations, uses, or adaptations of the present invention, which follow the general principles of the present invention and include the common general knowledge or conventional technical means in the technical field not disclosed in the present invention. The specification and examples are only regarded as exemplary.

[0136] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A system for recycling waste heat from flue gas released by dry quenching of coke, used in a dry quenching furnace system, the dry quenching furnace system comprising a dry quenching furnace and a dust removal device, characterized in that: The recycling system comprises: A combustion device, including a smoke inlet and a smoke outlet; a first smoke inlet assembly, wherein a first end of the first smoke inlet assembly is connected to a smoke duct behind a dry quenching furnace fan, and a second end of the first smoke inlet assembly is connected to the smoke inlet; a second smoke introduction component, wherein a first end of the second smoke introduction component is connected to the smoke emission duct on the top of the CDQ furnace, and a second end of the second smoke introduction component is connected to the smoke inlet; The smoke outlet assembly is used to connect the smoke outlet and the dust removal device.

2. The system for recycling waste heat from flue gas released by dry coke quenching according to claim 1 is characterized in that: The recycling system also includes: A nitrogen supplement component, used for connecting the flue gas outlet component and the nitrogen production station; The nitrogen supplement component comprises: A nitrogen pipeline, used to connect the flue gas outlet assembly and the nitrogen production station; The pressure reducing valve group and the solenoid valve are arranged on the nitrogen pipeline.

3. The system for recycling waste heat of flue gas released by dry coke quenching according to claim 1 is characterized in that: The first flue gas introduction component comprises: A first smoke duct, used for connecting the smoke inlet and the smoke duct after the fan; A first switching valve is arranged on the first flue gas duct; A pressurizing fan is arranged on the first flue gas duct, and the pressurizing fan is located on the first switching valve.

4. The system for recycling waste heat from flue gas released by dry coke quenching according to claim 3 is characterized in that: The first smoke inlet assembly further comprises: A first expansion joint is arranged on the first flue gas duct, and the first expansion joint is arranged close to the flue gas inlet; The first monitoring device is arranged in the first flue gas duct, and controls the switching of the first switching valve according to the monitoring result of the first monitoring device.

5. The system for recycling waste heat from flue gas released by dry coke quenching according to claim 1 is characterized in that: The second flue gas introduction component comprises: A second smoke duct, used for connecting the smoke inlet and the smoke duct on the furnace top; A second switching valve is arranged on the second flue gas duct; A check valve is provided on the second flue gas duct, wherein the check valve is located above the second switching valve; The first heat-insulating component is externally mounted on the second flue gas duct.

6. The system for recycling waste heat from flue gas released by dry coke quenching according to claim 5 is characterized in that: The second smoke inlet assembly further comprises: A second expansion joint is arranged on the second flue gas duct, and the second expansion joint is arranged close to the flue gas inlet; The second monitoring device is arranged in the second flue gas duct, and the switching of the second switching valve is controlled according to the monitoring result of the second monitoring device.

7. The system for recycling waste heat from flue gas released by dry coke quenching according to claim 1 is characterized in that: The combustion device comprises: a combustion chamber; and A first smoke inlet and a second smoke inlet are arranged on the combustion chamber, the first smoke inlet is connected to the first smoke introduction component, and the second smoke inlet is connected to the second smoke introduction component; A flame monitoring device, arranged at the first smoke inlet and the second smoke inlet; A combustion-supporting pipeline connected to the air inlet of the combustion device, a combustion-supporting fan is provided on the combustion-supporting pipeline, and the air inlet is arranged on the combustion chamber; An explosion relief pipe is arranged on the combustion chamber, and an explosion relief valve is arranged on the explosion relief pipe.

8. The system for recycling waste heat from flue gas released by dry coke quenching according to claim 7 is characterized in that: The combustion device also includes: A dust discharge device is arranged below the combustion chamber, the dust discharge device is communicated with the combustion chamber, and the dust discharge device is arranged opposite to the explosion relief pipe; The material level meter is arranged in the dust discharge device.

9. The system for recycling waste heat from flue gas released by dry coke quenching according to claim 2 is characterized in that: The smoke outlet assembly comprises: A smoke outlet pipe, used to connect the smoke outlet and the dust removal device; A third switching valve is arranged on the smoke outlet pipe; A third expansion joint is arranged at one end of the smoke outlet pipe close to the smoke outlet; A second heat-insulating member, which is externally mounted on the smoke outlet pipe; The third monitoring device is arranged in the flue gas outlet pipe, and the opening and closing of the nitrogen supplement component is controlled by the monitoring result of the third monitoring device.

10. A method for recycling waste heat from flue gas released by dry coke quenching, using the recycling system according to any one of claims 1 to 9, characterized in that: The recycling method comprises: Collect the first flue gas in the flue gas duct behind the fan, and collect the second flue gas in the flue gas duct on the top of the furnace; Mixing the first flue gas and the second flue gas and burning them to form combustion ash and combustion gas; The combustion ash is discharged, and the burner enters the dust removal device and then participates in the boiler combustion.

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