A coke oven flue gas treatment system

Abstract

The present application provides a kind of coke oven flue gas treatment system, and the flue gas generated by coke oven is discharged by flue, and the treatment system includes: cooling section, cooling section carries out cooling to the flue gas discharged by flue;Desulfurization system, the gas inlet of desulfurization system is connected with the gas outlet of cooling section, for carrying out desulfurization treatment to the flue gas after cooling;Heating section, the gas inlet of heating section is connected with the gas outlet of desulfurization system, for heating to the flue gas after desulfurization treatment;De-nitration tower, the gas inlet of de-nitration tower is connected with the gas outlet of heating section, for carrying out de-nitration treatment to the flue gas after heating;Exhaust system, exhaust system is connected with the gas outlet of de-nitration tower, for discharging the flue gas after de-nitration treatment, the present application increases the success rate of de-nitration reaction and desulfurization reaction, gets rid of the constraint factor that de-nitration reaction is not good by adsorption effect, improves the independence and flexibility of desulfurization and de-nitration reaction, enhances the effect of flue gas treatment.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of flue gas treatment, in particular to a coke oven flue gas treatment system. BACKGROUND

[0002] In recent years, in response to the pollutant emission index requirements of some large domestic steel enterprises, activated coke desulfurization and denitrification process is matched for newly built sintering projects, but there are still some deficiencies in the actual operation and debugging process.

[0003] The existing activated coke desulfurization and denitrification process runs jointly in desulfurization and denitrification, but in the denitrification process, the SO2 in the flue gas entering the denitrification section must be generally required to be less than 50mg / Nm 3 If the desulfurization of the adsorption tower exceeds the standard, the denitrification section will continue to adsorb SO2, and the ammonia injection system cannot be put into operation, NO X Will be removed. If continuous breakthrough operation is continued, it will cause the treatment capacity of the analysis system to increase, which may exceed the capacity of the analysis system, and also cause the NO X Adsorbed by activated coke in the rich gas will be resolved, affecting the operation of the subsequent salt or acid system and reducing the quality of the by-products. Increasing the difficulty of selling by-products. If ammonia is forcibly injected, it will cause excessive SO2 to react with ammonia to generate by-products such as ammonium sulfite, which is not conducive to the adsorbent and the safe temperature operation of the system.

[0004] Secondly, in the traditional denitrification process, the activated coke process has a relatively strict requirement for hot spot control, so the processing precision must be strictly controlled during the installation and manufacturing of the adsorption tower to ensure that the adsorption system meets the air tightness requirement. However, this control is relatively difficult, especially for projects with large amounts of flue gas and many adsorption modules, leak detection work is quite difficult, and it is not one-time through test, and needs to be repeated several times to pass the acceptance. And only after the air tightness of the adsorption module is accepted, the coke loading work can be carried out. Most projects use cranes to load coke initially because the chain bucket machine is not installed in place. The larger the amount of coke loaded, the higher the cost of coke loading, which increases the construction cost of the project. SUMMARY

[0005] The purpose of the present application is to provide a coke oven flue gas treatment system, which realizes the success rate of increasing the denitrification reaction and the desulfurization reaction, and gets rid of the restriction of the poor adsorption effect of the denitrification reaction.

[0006] In order to achieve the above purpose, the present application provides the following technical scheme:

[0007] A coke oven flue gas treatment system, flue gas generated by a coke oven is discharged by a flue, the treatment system comprising: a cooling section, the cooling section cooling the flue gas discharged by the flue; a desulfurization system, the gas inlet of the desulfurization system being connected with the gas outlet of the cooling section, for desulfurization treatment of the cooled flue gas; a heating section, the gas inlet of the heating section being connected with the gas outlet of the desulfurization system, for heating the desulfurization treated flue gas; a denitration tower, the gas inlet of the denitration tower being connected with the gas outlet of the heating section, for denitration treatment of the heated flue gas; an exhaust system, the exhaust system being connected with the gas outlet of the denitration tower, for discharging the denitration treated flue gas. Further, an induced draft fan is further included, the flue gas discharged by the flue is sucked into the cooling section by the induced draft fan.

[0008] Further, the desulfurization system comprises a plurality of adsorption units, the flue gas is collected after being adsorbed by a plurality of the adsorption units and is discharged from the gas outlet of the desulfurization system.

[0009] Further, an ammonia water storage and delivery system and a clean sulfur flue gas delivery pipeline are further included, the clean sulfur flue gas delivery pipeline is used for delivering the flue gas discharged by the heating section into the denitration tower, the liquid outlet of the ammonia water storage and delivery system is connected with the clean sulfur flue gas delivery pipeline, and the ammonia water storage and delivery system delivers liquid into the clean sulfur flue gas delivery pipeline by means of atomized injection.

[0010] Further, a resolving tower is further included, the resolving tower is used for resolving saturated adsorbent in the desulfurization system, and the resolved adsorbent is delivered into the desulfurization system.

[0011] Further, an adsorbent circulation system is further included, the adsorbent circulation system comprises an adsorbent chain bucket elevator, a vibrating screen, an air screen, a bag dust collector and a new activated carbon bin, the adsorbent chain bucket elevator is used for delivering the resolved adsorbent into the vibrating screen, the vibrating screen performs primary screening on the resolved adsorbent, the resolved adsorbent after primary screening is subjected to secondary screening by the air screen, the adsorbent chain bucket elevator delivers the resolved adsorbent after secondary screening into the desulfurization system, the bag dust collector is used for dust removal of the vibrating screen, and the new activated carbon bin is used for supplementing adsorption material between the vibrating screen and the air screen.

[0012] Further, a rich gas fan and a sulfuric ammonium production section are further included, the rich gas fan delivers the sulfur-rich gas in the resolving tower into the sulfuric ammonium production section; preferably, an acid making system is further included, the rich gas fan delivers the sulfur-rich gas in the resolving tower into the acid making system.

[0013] Further, a fire-fighting nitrogen system is further included, the fire-fighting nitrogen system communicates with the desulfurization system and the resolving tower.

[0014] Further, a waste heat recovery system is further included for recovering waste heat of the denitration tower exhaust gas; the waste heat recovery system is arranged between the denitration tower and the exhaust system, and is used for recovering waste heat of the denitration tower exhaust gas; preferably, the waste heat recovery system is an ammonia water heat exchange system or a waste heat boiler system.

[0015] Further, a hot air heating system is further included, which comprises a hot air furnace, a combustion air fan, a cooling fan and a waste heat recovery fan; the hot air furnace provides heat for the denitration tower and the stripping tower, the cooling fan is used for extracting flue gas from the smoke outlet of the waste heat recovery system, the flue gas extracted by the cooling fan is mixed with flue gas discharged from the smoke outlet of the hot air furnace and then sent into the stripping tower for heat stripping, and the waste heat recovery fan is used for conveying flue gas after heat exchange in the heating section of the stripping tower to the waste heat recovery system.

[0016] It can be known from the analysis that the coke oven flue gas treatment system has the following beneficial effects compared with the prior art: the desulfurization system and the denitration tower are arranged separately, so that the denitration reaction and the desulfurization reaction are carried out separately, the reaction temperature can be changed according to the reaction type, the success rate of the denitration reaction and the desulfurization reaction is increased, the denitration reaction is freed from the constraint factor of poor adsorption effect, the independence and flexibility of the desulfurization and denitration reactions are improved, the flue gas treatment effect is enhanced, and the concentrated ammonia water is directly sprayed into the denitration tower through the ammonia water storage and conveying system, without the need for auxiliary systems such as ammonia evaporation and ammonia dilution, so that energy and cost are saved. BRIEF DESCRIPTION OF DRAWINGS

[0017] The drawings accompanying the specification of this application form a part thereof, serve to provide further understanding of the application, and together with the description of the exemplary embodiments of the application given below, serve to explain the application, and do not constitute an improper limitation on the application. Among them:

[0018] Figure 1 A structural block diagram of a coke oven flue gas treatment system according to an embodiment of the application.

[0019] Figure 2 A structural schematic diagram of a closed circulating water system of a coke oven flue gas treatment system according to an embodiment of the application.

[0020] In the figure: 1 - coke oven flue; 2 - coke oven coke side flue; 3 - dry quenching flue; 4 - cooling section; 5 - induced draft fan; 6 - desulfurization system; 7 - heating section; 8 - closed circulating water system; 9 - denitration tower; 10 - waste heat recovery system; 11 - exhaust system; 12 - ammonia water storage and transportation system; 13 - resolving tower; 14 - ammonium sulfate production section; 15 - hot blast stove; 16 - vibrating screen; 17 - air screen; 18 - fire-fighting nitrogen system; 19 - environmental dust remover; 20 - new activated carbon bin; 21 - cooling fan; 22 - waste heat recovery fan; 23 - softening water circulating main pipeline; 24 - softening water return pipeline; 25 - softening water circulating pump; 26 - pressure gauge; 27 - return valve. DETAILED DESCRIPTION

[0021] The present application will be described in detail below with reference to the attached drawings and embodiments. Various examples are provided by way of explanation of the present application and are not meant as a restriction on the present application. In fact, it will be apparent to those skilled in the art that modifications and variations can be made in the present application without departing from the scope or spirit of the application. For example, features that are shown or described as part of one embodiment can be used on another embodiment to produce still a further embodiment. It is, therefore, desired that the present application be considered in its broadest aspect and be interpreted to be as broad as is legally permissible. It is intended that the present application cover modifications and variations of this application provided they come within the scope of the appended claims and their equivalents.

[0022] In the description of the present application, the terms "longitudinal", "transverse", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application, and are not required to be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. The terms "connected", "connected", "provided" used in the present application should be broadly understood, for example, it can be fixedly connected, or it can be detachably connected; it can be directly connected, or it can be indirectly connected through an intermediate part; it can be wired electrical connection, wireless electrical connection, or wireless communication signal connection, and the specific meaning of the above terms can be understood by those skilled in the art according to the specific circumstances.

[0023] One or more examples of the present application are shown in the accompanying drawings. The detailed description uses numerical and letter designations to refer to features in the drawings. Like or similar designations in the drawings and description have been used to label like or similar parts of the present application. As used herein, the terms "first", "second", "third", and "fourth" are used interchangeably to distinguish one element from another and are not intended to signify location or importance of the individual elements.

[0024] As Figure 1As shown, according to the embodiment of the present application, a coke oven flue gas treatment system is provided, the flue gas generated by the coke oven is discharged from the flue, and the treatment system comprises:

[0025] A cooling section 4 is arranged to cool the flue gas discharged from the flue, and in the present system, the cooling section 4 is arranged to control the temperature of the flue gas entering the SO2 adsorption system, i.e. the desulfurization system 6 (120-130℃), so that the flue gas enters the desulfurization system 6 at a temperature lower than the ignition point, wherein the cooling section 4 is a cooling part of the closed water circulation heat exchange device.

[0026] A desulfurization system 6 is connected with the gas outlet of the cooling section 4, and is arranged to desulfurize the cooled flue gas, so that the flue gas cooled by the cooling section 4 enters the desulfurization system 6 to be desulfurized.

[0027] A heating section 7 is connected with the gas outlet of the desulfurization system 6, and is arranged to heat the flue gas treated by the desulfurization system, and the heating section 7 and the cooling section 4 are connected through a closed circulation water system 8 to circulate the temperature. As shown, Figure 2 As shown, the closed circulation water system 8 is arranged between the heating section 7 and the cooling section 4, and the closed circulation water system 8 comprises a softened water circulation main pipeline 23, a softened water return pipeline 24, a softened water circulation pump 25, a pressure gauge 26 and a return valve 27. The softened water circulation main pipeline 23 is connected between the heating section 7 and the cooling section 4 to form a heat exchange circulation loop of the heating section 7 and the cooling section 4. The softened water return pipeline 24 is connected to the softened water circulation main pipeline 23 and communicates with both ends of the heating section 7, and the softened water return pipeline 24 and the softened water circulation main pipeline 23 share a section of pipeline. The softened water circulation pump 25 is arranged on the pipeline shared by the softened water return pipeline 24 and the softened water circulation main pipeline 23, and the circulation of the softened water in the softened water circulation main pipeline 23 and the softened water return pipeline 24 can be controlled through the softened water circulation pump 25. The flow of the softened water circulation pump 25 is monitored through the pressure gauge 26. Two softened water circulation pumps 25 can be arranged in parallel on the softened water circulation main pipeline 23 between the heating section 7 and the cooling section 4. One softened water circulation pump 25 is used as the main pump, and the other softened water circulation pump 25 is used as the standby pump. When the main softened water circulation pump 25 fails, the standby softened water circulation pump 25 can be started to make the present system work normally. The heat exchange medium is preferably softened water. The heat exchange medium heated by the flue gas in the cooling section 4 enters the heating section 7 as the heat source medium of the heating section 7, and then part of the heat exchange medium cooled in the heating section 7 flows into the cooling section 4 through the softened water circulation main pipeline 23, and part of the heat exchange medium flows back into the heating section 7 through the softened water return pipeline 24. If necessary, the softened water in the heating section 7 can also be returned to the cooling section 4 for cooling the flue gas. The softened water return pipeline 24 comprises an auxiliary pipeline 28 connected with the heating section 7 and the cooling section 4, and the auxiliary pipeline 28 is connected with the softened water circulation main pipeline 23 and the softened water return pipeline 24. Figure 2The uppermost pipe with left arrow in the middle represents the softened water circulation main pipe 23, which comprises an attached Figure 2 The lowermost pipe with left arrow in the middle represents the public pipe, which comprises an attached Figure 2 The middle pipe with right arrow in the middle represents the softened water return pipe 24, which controls the amount of softened water actually entering the heating section 7 through the return valve 27, thereby controlling the heat exchange amount of the closed circulation water system and the flue gas temperature at the outlet of the cooling section 4, so as to meet the temperature requirement of the desulfurization reaction; the softened water circulation main pipe 23 transfers the heat of the cooling section 4 and the heating section 7 through water medium, shifts the heat of the flue gas, fully utilizes the self heat of the coke oven flue gas, and increases the temperature of the flue gas at the gas inlet of the denitration tower 9, so as to reduce the catalytic supplemental heat during the denitration reaction, save the gas consumption, reduce the heat power of the heating system, save the operation cost of the denitration work and the one-time investment of the related equipment, wherein the heating section 7 is the temperature increasing part of the closed water circulation heat exchange device.

[0028] The denitration tower 9 is an SCR denitration tower (selective catalytic reduction denitration tower), the gas inlet of the denitration tower 9 is connected with the gas outlet of the heating section 7, and is used for carrying out denitration treatment on the heated flue gas; the denitration tower 9 adopts a double module design, two sets of SCR reactor modules (selective catalytic reduction reactor modules) are designed in the denitration tower 9 according to 50% of the flue gas amount, the inlet and outlet of each set of SCR reactor module are additionally provided with baffle seals, when one SCR reactor module needs to be replaced, the load of the coke oven is reduced to reduce the flue gas discharged, so that the other SCR reactor module can complete the entire denitration work, thereby the non-working SCR reactor module is replaced, the on-line replacement is realized by reducing the load of the coke oven, and the nitrogen oxide emission index is not affected during the replacement process, and the utilization rate is improved. The specific working process is as follows: after the clean sulfur flue gas is heated by the heating section 7, the temperature reaches 220-240 DEG C, the concentrated ammonia water with a concentration (volume fraction) of 18%-20% is directly sprayed into the gas inlet of the denitration tower 9, the ammonia-containing flue gas mixed by the static mixer in the denitration tower 9 is heated by the external burner of the denitration tower 9, reaches the window temperature of the medium-low temperature catalyst, and then removes the nitrogen oxides in the flue gas through the catalytic reduction reaction; and the selective catalytic reduction denitration reactor adopts a double module design, and the catalyst can be replaced on-line.

[0029] The present application replaces the denitration section in the existing adsorption tower with a medium-low temperature SCR, and the medium-low temperature refers to a temperature of 250-280 DEG C. The problems mentioned in the background art can be solved, the desulfurization and denitration are independently arranged, the influence of SO2 on the denitration reaction is reduced, the denitration tower 9 does not continue to absorb SO2, the ammonia spraying system is normally put into operation, the NO X is not removed in a lagging manner.

[0030] Secondly, replacing the traditional denitrification section of the denitrification tower 9 with a selective catalytic reduction (SCR) denitrification reactor eliminates the need for coking in the denitrification section and reduces the system's airtightness requirements. Because activated coke technology has strict requirements for hot spot control, the manufacturing and installation of the denitrification tower 9 must strictly control processing precision to ensure the adsorption system meets airtightness requirements. However, this is difficult to control, especially for projects handling large volumes of flue gas with numerous adsorption modules. Leak detection is extremely challenging and requires repeated testing before acceptance. Furthermore, coking can only proceed after the adsorption modules have passed airtightness testing. Many projects use cranes for initial coking because the chain bucket elevator is not yet fully installed; the larger the coking volume, the higher the cost, thus increasing construction costs. In contrast, the catalyst loading of the SCR reactor is unaffected by the airtightness testing of the adsorption system or the coking process. Catalyst installation is more time- and labor-saving than coking, and the SCR denitrification reactor has a simpler structure, making airtightness checks easier. In summary, adopting the independent desulfurization and denitrification design in this invention can shorten the project construction cycle, especially for projects with tight schedules.

[0031] The exhaust system 11 is connected to the gas outlet of the denitrification tower 9 and is used to discharge the flue gas after denitrification treatment. The exhaust system 11 can be a chimney.

[0032] Because the desulfurization and denitrification reactions are separated in this system, their independence and flexibility are improved. This largely eliminates the constraint of poor adsorption in the denitrification reaction.

[0033] Preferably, a coke oven flue gas treatment system further includes an induced draft fan 5, which draws the flue gas discharged from the flue into the cooling section 4. This system is a positive pressure operating system, and the induced draft fan 5 can introduce the flue gas discharged from the flue into the cooling section 4.

[0034] Preferably, the desulfurization system 6 includes multiple adsorption units. After the flue gas is adsorbed by multiple adsorption units, it is collected and discharged from the gas outlet of the desulfurization system 6. Multiple adsorption units can improve the overall adsorption effect and make the flue gas adsorption more thorough. The adsorption units are existing products and can be directly applied to this system.

[0035] Preferably, the coke oven flue gas treatment system further comprises an ammonia water storage and delivery system 12 and a clean sulfur flue gas delivery pipeline for delivering the flue gas discharged from the heating section 7 into the denitration tower 9, the liquid outlet of the ammonia water storage and delivery system 12 is connected with the clean sulfur flue gas delivery pipeline, and the ammonia water storage and delivery system 12 delivers liquid into the clean sulfur flue gas delivery pipeline by means of atomized injection; in the production process, for the active coke process, the ammonia gas preparation system generally needs to use the ammonia water vaporization mode, and after being diluted by the dilution air, the ammonia gas is injected into the denitration section of the adsorption system, the more the adsorption system modules, the more complex the injection system distribution pipeline, and the evaporator cannot achieve zero discharge of waste water, which increases the difficulty of subsequent waste water treatment. However, by using the independent design mode of desulfurization and denitration as in the present application, the ammonia water as a reducing agent can directly enter the inlet channel of the selective catalytic reduction denitration reactor by means of high-pressure atomized injection, the ammonia water is supplied into the clean sulfur flue gas delivery pipeline between the denitration tower 9 and the heating section 7 in a direct injection mode after high-pressure atomization by a double-fluid lance, the number and specifications of the lances are selected according to the theoretical consumption of ammonia water, and the ammonia-containing flue gas is mixed with the flue gas, and the denitration reaction is completed when the ammonia-containing flue gas flows through the catalyst, the ammonia gas and the flue gas are fully mixed before entering the selective catalytic reduction denitration reactor, which is simpler and more direct in the process, the injection and atomization effects of a single lance can be directly observed and adjusted, and there is no need to configure a remote instrument. Therefore, the configuration of the corresponding electrical instrument control and process equipment can be reduced, and the project cost is further optimized. Therefore, the ammonia water of the ammonia water storage and delivery system 12 is injected into the denitration tower 9 by means of injection, and since there is no need for auxiliary systems such as ammonia evaporation and ammonia dilution, it has energy-saving advantages, and in combination with the external burner in the denitration tower 9, the combustion loss can be reduced, the heat utilization rate can be improved, and the coal gas consumption can be saved.

[0036] Preferably, the coke oven flue gas treatment system further comprises a resolving tower 13 for resolving the saturated adsorbent in the desulfurization system 6, and the resolved adsorbent is delivered into the desulfurization system 6.

[0037] Preferably, the coke oven flue gas treatment system further comprises an adsorbent circulating system, the adsorbent circulating system comprises an adsorbent chain bucket elevator, a vibrating screen 16, a wind screen 17 and a bag dust collector 19, the adsorbent chain bucket elevator is used to transport the desorbed adsorbent to the vibrating screen 16, the vibrating screen 16 performs primary screening on the desorbed adsorbent, the desorbed adsorbent that has passed the primary screening is subjected to secondary screening by the wind screen 17, the adsorbent chain bucket elevator transports the desorbed adsorbent that has passed the secondary screening to the desulfurization system 6, the bag dust collector 19 is used to remove dust from the vibrating screen 16, the desorbed adsorbent is transported by the chain bucket elevator to the vibrating screen 16, the desorbed adsorbent that meets the particle size requirement is transported by the chain bucket elevator to the wind screen 17 for secondary removal of fine dust, and the qualified desorbed adsorbent is transported by the chain bucket elevator to the desulfurization system 6 or the denitration tower 9 for recycling. The new activated carbon bin 20 is used to supplement the adsorbent between the vibrating screen 16 and the wind screen 17, when the adsorbent in the desulfurization system 6 is insufficient, new adsorbent can be obtained from the new activated carbon bin 20, and the new adsorbent obtained from the new activated carbon bin 20 is preferably supplemented after the vibrating screen 16 and before the wind screen 17, that is, the new adsorbent obtained from the new activated carbon bin 20 only passes through the wind screen 17 and does not pass through the vibrating screen 16. Because the new adsorbent obtained from the new activated carbon bin 20 is qualified, it does not need to pass through the vibrating screen 16 for screening.

[0038] Preferably, the coke oven flue gas treatment system further comprises a gas-rich fan and an ammonium sulfate production section 14, the gas-rich fan transports the sulfur-rich gas in the desorption tower 13 to the ammonium sulfate production section 14, and the gas-solid byproducts generated in the production process of the system mainly refer to the sulfur-rich gas and the adsorbent powder. The sulfur-rich gas can be transported by the gas-rich fan to the ammonium salt preparation system of the ammonium salt production workshop to prepare ammonium salt, without the need to reconfigure the salt production system. The adsorbent powder screened by the wind screen 17 and the vibrating screen 16 in the production process of the system can be granulated by a granulation system and then transported to the desorption tower 13 for secondary use after desorption, or can be used as raw material of the primary filtration system of the coking plant wastewater treatment system for preliminary filtration to reduce the input of new reagents.

[0039] Preferably, the coke oven flue gas treatment system further comprises an acid production system, the gas-rich fan transports the sulfur-rich gas in the desorption tower 13 to the acid production system, the sulfur-rich gas desorbed from the desorption tower 13 is introduced by the gas-rich fan to the acid production system to produce 98% concentrated sulfuric acid, or can be introduced to the salt production system to produce ammonium sulfate or sodium metabisulfite and other salt substances.

[0040] Preferably, the coke oven flue gas treatment system further comprises a fire-fighting nitrogen system 18, the fire-fighting nitrogen system 18 communicates with the desulfurization system 6 and the desorption tower 13, and when the adsorbent of the desulfurization system 6 or the desorption tower 13 has a hot spot, nitrogen protection can be performed on the desulfurization system 6 or the desorption tower 13 by the fire-fighting nitrogen system 18.

[0041] Preferably, the coke oven flue gas treatment system further comprises a waste heat recovery system 10, which is an ammonia water heat exchange system or a waste heat boiler system, and the waste heat recovery system 10 is used to recover the waste heat of the flue gas discharged from the denitration tower 9.

[0042] The ammonia water heat exchange system is arranged between the denitration tower 9 and the exhaust system 11, and is arranged in combination with the characteristics of the ammonia water evaporation and purification process in the coking plant production section. The main principle of this section is to reuse the high-temperature heat of the flue gas after the denitration reaction to indirectly heat the circulating liquid in the ammonia stripping tower kettle to vaporize it. Since the steam stripping method is usually used in the ammonia stripping section of the production workshop to purify ammonia gas. After using this process, the existing ammonia stripping tower can use less steam or no steam to reduce the discharge of ammonia stripping tower wastewater and the use of steam, thereby achieving the purpose of energy saving and consumption reduction.

[0043] When the waste heat boiler system is used, the waste heat boiler system is used to recover the waste heat of the flue gas discharged from the denitration tower 9. In order to make full use of the heat of the flue gas after denitration of the denitration tower 9, the waste heat boiler system is specially arranged, which generates steam for heat tracing and heat preservation of the denitration tower 9 and the stripping tower 13, and the excess part is connected to the owner's steam pipe network. The waste heat boiler system mainly consists of an evaporator, a steam accumulator, a soft water heater, an oxygen remover, a steam drum and a steam-water pipeline. The main principle is that the heat of the flue gas after denitration is transferred to the saturated water in the water jacket pipe through the evaporator heat exchange pipe, and the saturated water is vaporized. The produced steam and steam-water mixture reaches the steam drum through the steam rising pipe, and then is separated into steam and water, and then is output through the main steam valve. In this way, the heat pipe continuously inputs heat to the finned heat pipe working medium, and the steam-water cycle is completed through the rising and descending pipes, so that the flue gas heat is converted into steam.

[0044] Preferably, the hot air heating system further comprises a hot air furnace 15, a combustion air fan, a cooling fan 21 and a waste heat recovery fan 22. The combustion air fan is in communication with the hot air furnace 15, and the combustion air fan is used to provide oxygen for the hot air furnace 15. The hot air furnace 15 provides heat for the denitration tower 9 and the stripping tower 13. The cooling fan 21 is used to extract flue gas from the flue gas outlet of the waste heat recovery system 10. The flue gas extracted by the cooling fan 21 is mixed with the flue gas discharged from the flue gas outlet of the hot air furnace 15, and then is sent into the stripping tower 13 for thermal stripping. The temperature of the flue gas discharged from the flue gas outlet of the hot air furnace 15 is 900-1200°C, and the temperature is reduced to 480-490°C after being mixed with the flue gas extracted by the cooling fan 21. The waste heat recovery fan 22 is used to transport the flue gas after heat exchange in the heating section of the stripping tower 13 to the inlet flue of the waste heat recovery system 10 for heat recovery. The temperature of the flue gas after thermal stripping in the stripping tower 13 is 300-310°C.

[0045] Preferably, the flue comprises a coke oven machine side flue 1, a coke oven coke side flue 2 and a dry quenching flue 3. The flue gas generated by the coke oven is discharged from the coke oven machine side flue 1, the coke oven coke side flue 2 and the dry quenching flue 3 and enters the cooling section 4.

[0046] From the above description, it can be seen that the above-mentioned embodiments of the present application achieve the following technical effects:

[0047] 1. The SO2 adsorption desulfurization reaction on the moving bed is separated from the selective catalytic reduction low-temperature denitration catalytic reaction, and the SO2 adsorption desulfurization reaction and the selective catalytic reduction low-temperature denitration catalytic reaction are independently processed, thereby improving the independence and flexibility of the desulfurization and denitration reactions. To a great extent, the denitration reaction is freed from the constraint factor of poor adsorption effect, that is, even if individual adsorption units exceed the standard (SO2>100 mg / Nm 3 ), as long as the overall concentration of SO2 in the denitration flue is less than 50 mg / Nm 3 , all adsorption units can be fully used, and the ammonia injection of the denitration system is not affected, the later debugging period can be shortened, and the debugging cost can be saved.

[0048] 2. The denitration tower 9 cooperates with the ammonia water storage and conveying system 12 to realize the concentrated ammonia water direct injection process, without the need for auxiliary systems such as ammonia evaporation and ammonia dilution, and has energy-saving advantages.

[0049] 3. The system realizes the system internal recycling use of the adsorbent through the analysis tower 13, and also has the advantage of the selective catalytic reduction process that meets the high denitration efficiency under the condition of low ammonia escape at present. The design is more reasonable.

[0050] Compared with the prior art, the present application separates the denitration reaction and the desulfurization reaction, thereby freeing the denitration reaction from the constraint factor of poor adsorption effect, improving the independence and flexibility of the desulfurization and denitration reactions, enhancing the effect of flue gas treatment, and directly spraying concentrated ammonia water into the denitration tower 9 through the ammonia water storage and conveying system 12, without the need for auxiliary systems such as ammonia evaporation and ammonia dilution, thereby saving energy and cost.

[0051] The above-mentioned is only the preferred embodiment of the present application, and is not used to limit the present application. For those skilled in the art, the present application can have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A coke oven flue gas treatment system, characterized by, The flue gas generated by the coke oven is discharged by a flue, and the treatment system comprises: a cooling section for cooling the flue gas discharged by the flue; a desulfurization system, a gas inlet of which is connected with a gas outlet of the cooling section, for desulfurization treatment of the cooled flue gas; a heating section, a gas inlet of which is connected with a gas outlet of the desulfurization system, for heating the desulfurization-treated flue gas; a denitration tower, a gas inlet of which is connected with a gas outlet of the heating section, for denitration treatment of the heated flue gas; an exhaust system, which is connected with a gas outlet of the denitration tower, for discharging the denitration-treated flue gas; an ammonia water storage and delivery system, and a clean sulfur flue gas delivery pipeline for delivering the flue gas discharged by the heating section to the denitration tower, a liquid outlet of the ammonia water storage and delivery system being connected with the clean sulfur flue gas delivery pipeline, and the ammonia water storage and delivery system delivering liquid into the clean sulfur flue gas delivery pipeline by means of atomized injection; a resolving tower for resolving saturated absorbent in the desulfurization system, the resolved absorbent being delivered to the desulfurization system; an absorbent circulation system, which comprises an absorbent chain bucket elevator, a vibrating screen, a wind screen, a bag-type dust collector and a new activated carbon bin, the absorbent chain bucket elevator being used to deliver the resolved absorbent to the vibrating screen, the vibrating screen being used to initially screen the resolved absorbent, the resolved absorbent after the initial screening being used to be secondarily screened by the wind screen, the resolved absorbent after the secondary screening being delivered to the desulfurization system by the absorbent chain bucket elevator, the bag-type dust collector being used to remove dust from the vibrating screen, and the new activated carbon bin being used to supplement absorbent material between the vibrating screen and the wind screen; a hot air heating system, which comprises a hot air furnace, a combustion air fan, a cooling fan and a waste heat recovery fan; a waste heat recovery system, which is used to recover waste heat of the gas discharged by the denitration tower; the hot air furnace provides heat for the denitration tower and the resolving tower, the cooling fan is used to extract flue gas from a flue gas outlet of the waste heat recovery system, the flue gas extracted by the cooling fan is mixed with flue gas discharged from a flue gas outlet of the hot air furnace and then is sent into the resolving tower for thermal resolution, and the waste heat recovery fan is used to deliver flue gas after heat exchange in a heating section of the resolving tower to the waste heat recovery system.

2. A coke oven flue gas treatment system according to claim 1, characterized in that, an induced draft fan is used to suck the flue gas discharged by the flue into the cooling section.

3. A coke oven flue gas treatment system according to claim 1, characterized in that, The desulfurization system comprises a plurality of adsorption units, and the flue gas is collected after being adsorbed by the plurality of adsorption units and is discharged from a gas outlet of the desulfurization system.

4. A coke oven gas treatment system according to claim 1, characterized in that, a gas enrichment fan and a sulfuric acid production section, the gas enrichment fan being used to deliver sulfur-rich gas in the resolving tower to the sulfuric acid production section; an acid production system, the gas enrichment fan being used to deliver sulfur-rich gas in the resolving tower to the acid production system.

5. A coke oven gas treatment system according to claim 1, characterized in that, a fire-fighting nitrogen system, which is communicated with the desulfurization system and the resolving tower.

6. A coke oven gas treatment system according to claim 1, characterized in that, The waste heat recovery system is arranged between the denitration tower and the exhaust system, and is used for recovering waste heat of the denitration tower exhaust gas. The waste heat recovery system is an ammonia water heat exchange system or a waste heat boiler system.

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