Method and system for dechlorination and desulfurization of blast furnace gas

Abstract

The present application relates to a method and system for dechlorination and desulfurization of blast furnace gas, comprising the following steps: gravity dust removal and cyclone dust removal of blast furnace gas to obtain pre-dust-removed gas; spraying a dechlorinating agent into the pre-dust-removed gas for dechlorination to obtain pre-dechlorinated gas; dry dust removal treatment of the pre-dechlorinated gas to obtain dechlorinated gas; hydrolysis treatment of the dechlorinated gas to obtain hydrolyzed gas; driving a TRT device with the hydrolyzed gas to perform power generation operations to obtain TRT post-gas; cooling and dehydrating the TRT post-gas to obtain dehydrated gas; treating the dehydrated gas with a desulfurization oxidizing liquid to convert hydrogen sulfide in the dehydrated gas into sulfur element to obtain desulfurized gas and sulfur-rich liquid. The present application has the advantages of small site occupation, no obstruction, saving agent consumption, and low equipment requirements for blast furnace gas dechlorination, and has the advantages of high desulfurization efficiency, strong adaptability to working conditions, and recoverable sulfur for blast furnace gas desulfurization.

Description

Technical Field

[0001] The present application relates to the field of environmental protection, and in particular to the dechlorination and desulfurization of blast furnace gas. Background Art

[0002] Blast furnace gas is a high-value byproduct in the production process of metallurgical steel enterprises. As a fuel, it is mainly used in blast furnace hot blast furnaces, steel rolling heating furnaces, gas-fired power generation and other users. It has become an important secondary energy source for metallurgical steel enterprises. In addition to the main components such as CO, CO2, and N2, blast furnace gas also contains trace components such as sulfide (total S≤200mg / Nm³) and hydrogen chloride (concentration 50~150mg / Nm³). Among them, the sulfur-containing components are finally discharged into the atmosphere in the form of SO2 after combustion, resulting in excessive SO2 emissions from end users. There are many end users of blast furnace gas and large flue gas emissions. The use of end flue gas treatment has many problems such as many points, large land occupation, high operating costs, and decentralized management. Chlorine-containing components mainly exist in the form of HCl, NH4Cl, etc., which will affect the stable operation of TRT (Top Gas Recovery Turbine, blast furnace gas residual pressure turbine power generation device), aggravate the corrosion of blast furnace pipe network and other ancillary equipment, and bring major production safety hazards.

[0003] For the dechlorination of blast furnace gas, the existing process mainly uses fixed bed dry method and condensation dehumidification method for dechlorination. Among them, fixed bed dry dechlorination removes HCl by adsorption of dechlorinating agent, which is simple to operate and has good purification effect, but the dechlorinating agent is limited by the chlorine capacity, large agent consumption, large site occupation, and large resistance loss. Condensation dehumidification dechlorination uses the characteristics of HCl being easily soluble in water. The dechlorination effect is limited by the temperature drop of coal gas, and it can only be placed after TRT. The wastewater under condensation is high in salt and has a low pH, which is difficult to handle. At the same time, due to the enrichment of a large amount of chloride ions, the material requirements for the condensation equipment are high. And after TRT, the coal gas needs to be heated and pressurized again, and the energy consumption is significantly increased.

[0004] For the desulfurization of blast furnace gas, the main method is to physically or chemically adsorb hydrogen sulfide through desulfurizers. The advantages are high absorption rate and no wastewater, while the disadvantages are low air velocity, large land area, high pressure drop, poor adaptability to working conditions, and limited by sulfur capacity. The amount of waste agent generated is large, which is difficult to handle and has high processing costs. Some renewable desulfurizers are often expensive, and the regeneration efficiency is not high. The regeneration equipment requires additional energy consumption and space.

[0005] In general, the existing blast furnace gas dechlorination and desulfurization process can achieve desulfurization and dechlorination effects in the short term, but it has major disadvantages in long-term operation. Summary of the invention

[0006] The embodiments of the present application provide a method and system for dechlorination and desulfurization of blast furnace gas to solve the technical problem that the existing blast furnace gas dechlorination and desulfurization process has major drawbacks in long-term operation.

[0007] In a first aspect, an embodiment of the present application provides a method for dechlorination and desulfurization of blast furnace gas, the method for dechlorination and desulfurization of blast furnace gas comprising the following steps:

[0008] Gravity dust removal and cyclone dust removal are performed on blast furnace gas to obtain pre-dust-removed gas;

[0009] spraying a dechlorinating agent into the pre-dust-removed coal gas for dechlorination to obtain pre-dechlorinated coal gas;

[0010] Performing dry dust removal treatment on the pre-dechlorinated coal gas to obtain dechlorinated coal gas;

[0011] hydrolyzing the dechlorinated coal gas to obtain hydrolyzed coal gas;

[0012] Using the hydrolyzed coal gas to drive a TRT device to perform power generation operations to obtain post-TRT coal gas;

[0013] Cooling and dehydrating the post-TRT coal gas to obtain dehydrated coal gas;

[0014] The dehydrated coal gas is treated with a desulfurization oxidizing liquid to convert hydrogen sulfide in the dehydrated coal gas into elemental sulfur, thereby obtaining desulfurized coal gas and sulfur-rich liquid.

[0015] In some embodiments of the present application, the dechlorinating agent is BKDCl-1 dechlorinating agent.

[0016] In some embodiments of the present application, the desulfurization oxidation liquid is an alkaline solution containing a DSH catalytic oxidant.

[0017] In some embodiments of the present application, the method for dechlorination and desulfurization of blast furnace gas further comprises the following steps:

[0018] performing oxidation treatment on the sulfur-rich liquid to obtain a sulfur-containing mixed liquid;

[0019] Separating sulfur from the sulfur-containing mixed liquid to obtain sulfur and regenerated desulfurized liquid;

[0020] The dehydrated coal gas is treated by using the regenerated desulfurization liquid as the desulfurization oxidation liquid.

[0021] In a second aspect, an embodiment of the present application provides a blast furnace gas dechlorination and desulfurization system, the blast furnace gas dechlorination and desulfurization system comprising:

[0022] A preliminary dust removal system, the preliminary dust removal system comprising a gravity dust removal device and a cyclone dust removal device;

[0023] Dechlorination agent injection system;

[0024] A dry dust removal system, wherein the preliminary dust removal system and the dechlorination agent spraying system are both connected to the dry dust removal system;

[0025] A hydrolysis system, connected to the dry dust removal system;

[0026] A TRT system, connected to the hydrolysis system;

[0027] a cooling system, in communication with the TRT system;

[0028] a dehydration system, connected to the cooling system;

[0029] The hydrogen sulfide absorption tower absorbs hydrogen sulfide by spraying the desulfurization oxidation liquid, and the hydrogen sulfide absorption tower is connected to the dehydration system.

[0030] In some embodiments of the present application, the dechlorination agent injection system comprises:

[0031] Dechlorinating agent raw material warehouse;

[0032] A dechlorinating agent buffer bin is connected to the dechlorinating agent raw material bin via a pumping mechanism;

[0033] A lock bucket is connected to the dechlorinating agent buffer bin through a valve;

[0034] The spray tank is connected with the above-mentioned dust removal system through a valve, and the spray tank is connected with the dry dust removal system.

[0035] In some embodiments of the present application, the preliminary dust removal system is connected to the dry dust removal system via a dechlorination pipeline, and the pipe wall of the dechlorination pipeline is provided with an opening for connecting to the spray tank.

[0036] In some embodiments of the present application, the blast furnace gas dechlorination and desulfurization system further comprises:

[0037] Regeneration tank;

[0038] Desulfurization oxidation liquid circulation pumping device;

[0039] Injector,

[0040] Among them, a sulfur-rich liquid tank is arranged at the bottom of the hydrogen sulfide absorption tower, and the sulfur-rich liquid tank is connected to the material inlet end of the desulfurization oxidation liquid circulating pumping device. The material outlet end of the desulfurization oxidation liquid circulating pumping device is provided with the injector, and the injector is used to inject the material pumped by the desulfurization oxidation liquid circulating pumping device into the regeneration tank.

[0041] In some embodiments of the present application, the blast furnace gas dechlorination and desulfurization system further includes a sulfur refining system, and the sulfur refining system includes:

[0042] A sulfur foam tank, used for collecting sulfur foam generated in the regeneration tank;

[0043] A filter press, wherein the filter press is connected to the sulfur foam tank via a pumping mechanism;

[0044] The sulfur melting kettle is used for melting the sulfur of the filter cake produced by the filter press.

[0045] In some embodiments of the present application, the TRT system is connected in parallel with a set of pressure reducing valves.

[0046] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0047] The dechlorination and desulfurization method of blast furnace gas provided in the embodiment of the present application is obtained by spraying a dechlorinating agent into the pre-dust-removed gas for dechlorination; then the pre-dechlorinated gas is subjected to dry dust removal treatment to remove the dechlorinating agent that has completed dechlorination, and the occupied space is small; by spraying the dechlorinating agent into the pre-dust-removed gas, there is no need for decompression and cooling, and there is no obstruction; the dechlorinating agent can be accurately fed by pre-calculating the hydrogen chloride content in the blast furnace gas, saving agent consumption; the dechlorination process is implemented in a dry state, there is no corrosion of the equipment by hydrochloric acid, and the equipment requirements are low. The present application treats the dehydrated gas by a desulfurization oxidation liquid, so that the hydrogen sulfide in the dehydrated gas is converted into sulfur element, and the dehydrated gas is treated by a desulfurization oxidation liquid, which has the advantages of high desulfurization efficiency and strong adaptability to working conditions, and the product is sulfur, which can be recovered, realizing desulfurization in the true sense, rather than transferring the pollutants and then processing them in subsequent steps. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0049] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0050] Figure 1 A schematic flow chart of a method for dechlorination and desulfurization of blast furnace gas provided in an embodiment of the present application. DETAILED DESCRIPTION

[0051] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0052] Unless otherwise specified, the terms used herein should be understood as commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art to which this application belongs. In the event of a conflict, this specification takes precedence.

[0053] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0054] The existing blast furnace gas dechlorination and desulfurization process has technical problems that cause serious disadvantages in long-term operation.

[0055] The technical solution provided by the embodiments of the present application is to solve the above technical problems, and the overall idea is as follows:

[0056] In a first aspect, an embodiment of the present application provides a method for dechlorination and desulfurization of blast furnace gas, the method for dechlorination and desulfurization of blast furnace gas comprising the following steps:

[0057] S1: Gravity dust removal and cyclone dust removal are performed on blast furnace gas to obtain pre-dust-removed gas;

[0058] S2: spraying a dechlorinating agent into the pre-dust-removed coal gas for dechlorination to obtain pre-dechlorinated coal gas;

[0059] S3: performing dry dust removal treatment on the pre-dechlorinated coal gas to obtain dechlorinated coal gas;

[0060] S4: hydrolyzing the dechlorinated coal gas to obtain hydrolyzed coal gas;

[0061] S5: using the hydrolyzed coal gas to drive the TRT device to perform power generation operations to obtain post-TRT coal gas;

[0062] S6: Cooling and dehydrating the post-TRT coal gas to obtain dehydrated coal gas;

[0063] S7: treating the dehydrated coal gas with a desulfurization oxidizing liquid to convert hydrogen sulfide in the dehydrated coal gas into elemental sulfur, thereby obtaining desulfurized coal gas and sulfur-rich liquid.

[0064] For the dechlorination of blast furnace gas, the existing process mainly uses fixed bed dry method and condensation dehumidification method for dechlorination. Among them, fixed bed dry dechlorination removes HCl by adsorption of dechlorinating agent, which is simple to operate and has good purification effect, but the dechlorinating agent is limited by the chlorine capacity, large agent consumption, large site occupation, and large resistance loss. Condensation dehumidification dechlorination uses the characteristics of HCl being easily soluble in water. The dechlorination effect is limited by the temperature drop of coal gas, and it can only be placed after TRT. The wastewater under condensation is high in salt and has a low pH, which is difficult to handle. At the same time, due to the enrichment of a large amount of chloride ions, the material requirements for the condensation equipment are high. And after TRT, the coal gas needs to be heated and pressurized again, and the energy consumption is significantly increased.

[0065] It is easy to understand that hydrolysis treatment refers to the catalytic hydrolysis desulfurization process of blast furnace gas. The organic sulfur in blast furnace gas mainly exists in the form of carbonyl sulfide (COS), accounting for about 70% of the total sulfide. Due to the stable chemical properties of COS, it is difficult to achieve deep purification through simple alkaline solution absorption or zinc oxide adsorption. Therefore, catalytic hydrolysis is regarded as one of the most promising methods for purifying COS in blast furnace gas. The catalytic hydrolysis method uses a specific catalyst to hydrolyze COS into hydrogen sulfide ( ) and carbon dioxide ( ), thereby achieving the removal of organic sulfur.

[0066] The present application obtains pre-dechlorinated coal gas by spraying a dechlorinating agent into the pre-dust-removed coal gas for dechlorination; then the pre-dechlorinated coal gas is subjected to dry dust removal treatment to remove the dechlorinating agent that has completed dechlorination, thereby occupying a small area; by spraying the dechlorinating agent into the pre-dust-removed coal gas, there is no need for reducing pressure and cooling, and there is no obstruction; the dechlorinating agent can be accurately dosed by pre-calculating the hydrogen chloride content in the blast furnace gas, thereby saving agent consumption; the dechlorination process is carried out in a dry state, there is no corrosion of hydrochloric acid to the equipment, and the equipment requirements are low.

[0067] The present application treats the dehydrated coal gas by means of a desulfurization oxidizing liquid, so that the hydrogen sulfide in the dehydrated coal gas is converted into elemental sulfur. The treatment of the dehydrated coal gas by means of a desulfurization oxidizing liquid has the advantages of high desulfurization efficiency and strong adaptability to working conditions, and the product is sulfur, which can be recovered, thus achieving true desulfurization, rather than transferring the pollutants and then processing them in subsequent steps.

[0068] In some embodiments of the present application, the dechlorinating agent is BKDCl-1 dechlorinating agent.

[0069] In some embodiments of the present application, the desulfurization oxidation liquid is an alkaline solution containing a DSH catalytic oxidant.

[0070] In some embodiments of the present application, the method for dechlorination and desulfurization of blast furnace gas further comprises the following steps:

[0071] S8: performing oxidation treatment on the sulfur-rich liquid to obtain a sulfur-containing mixed liquid;

[0072] S9: separating the sulfur in the sulfur-containing mixed liquid to obtain sulfur and regenerated desulfurized liquid;

[0073] S10: using the regenerated desulfurization liquid as the desulfurization oxidation liquid to treat the dehydrated coal gas.

[0074] It is easy to understand that the sulfur-rich liquid can restore its oxidation ability to hydrogen sulfide after being oxidized.

[0075] In a second aspect, an embodiment of the present application provides a blast furnace gas dechlorination and desulfurization system, the blast furnace gas dechlorination and desulfurization system comprising:

[0076] A preliminary dust removal system, the preliminary dust removal system comprising a gravity dust removal device and a cyclone dust removal device;

[0077] Dechlorination agent injection system;

[0078] A dry dust removal system, wherein the preliminary dust removal system and the dechlorination agent spraying system are both connected to the dry dust removal system;

[0079] A hydrolysis system, connected to the dry dust removal system;

[0080] A TRT system, connected to the hydrolysis system;

[0081] a cooling system, in communication with the TRT system;

[0082] a dehydration system, connected to the cooling system;

[0083] The hydrogen sulfide absorption tower absorbs hydrogen sulfide by spraying the desulfurization oxidation liquid, and the hydrogen sulfide absorption tower is connected to the dehydration system.

[0084] It is easy to understand that the hydrolysis system is a conventional system in TRT operation. As an example, the hydrolysis system can include a bypass valve group and an axial vertical multi-unit hydrolysis reactor.

[0085] It is easy to understand that the cooling system is a conventional system in TRT operations. As an example, the cooling system may include a spray cooling tower and a circulating pump set.

[0086] It is easy to understand that the dehydration system is a conventional system in TRT operations. As an example, the dehydration system can include a demisting tower and a demisting layer flushing system.

[0087] It is easy to understand that the dechlorination and desulfurization system for blast furnace gas described in any embodiment of the second aspect of the present application can implement the dechlorination and desulfurization method for blast furnace gas described in the first aspect of the present application. The preliminary dust removal system can be used to implement step S1. The dechlorination agent injection system can be used to implement step S2. The dry dust removal system can be used to implement step S3. The hydrolysis system can be used to implement step S4. The TRT system can be used to implement step S5. The cooling system and the dehydration system can be used to implement step S6. The hydrogen sulfide absorption tower can be used to implement step S7.

[0088] Since the blast furnace gas dechlorination and desulfurization system described in any embodiment of the second aspect of the present application can implement the blast furnace gas dechlorination and desulfurization method described in the first aspect of the present application, any embodiment of the second aspect of the present application has the beneficial effects of the blast furnace gas dechlorination and desulfurization method described in the first aspect of the present application, which will not be repeated here.

[0089] In some embodiments of the present application, the dechlorination agent injection system comprises:

[0090] Dechlorinating agent raw material warehouse;

[0091] A dechlorinating agent buffer bin is connected to the dechlorinating agent raw material bin via a pumping mechanism;

[0092] A lock bucket is connected to the dechlorinating agent buffer bin through a valve;

[0093] The spray tank is connected with the above-mentioned dust removal system through a valve, and the spray tank is connected with the dry dust removal system.

[0094] In some embodiments of the present application, the working mode of the dechlorinating agent spraying system is as follows: the dechlorinating agent is transported to the site by a tank truck and enters the dechlorinating agent raw material warehouse by pneumatic conveying. The pumping mechanism can be an ash tank pump. The dechlorinating agent raw material warehouse and the dechlorinating agent buffer warehouse are loaded with high-pressure nitrogen through an ash tank pump, and the nitrogen pressure can be 200~300kPa. The dechlorinating agent buffer warehouse and the lock bucket are connected by a gate valve and a dome valve, and the dechlorinating agent in the dechlorinating agent buffer warehouse falls into the lock bucket by gravity. The spray tank is always in pressurized operation, and the pressure of the spray tank should be more than 30kPa higher than the pressure at the blast furnace gas supply end. The lock bucket is connected to the spray tank by a dome valve, and the dechlorinating agent in the lock bucket enters the spray tank by pressurization. The pressure difference range between the lock bucket and the spray tank can be 5~50kPa.

[0095] In some embodiments of the present application, the preliminary dust removal system is connected to the dry dust removal system via a dechlorination pipeline, and the pipe wall of the dechlorination pipeline is provided with an opening for connecting to the spray tank.

[0096] The dechlorinating agent and the pre-dust-removed coal gas can be fully mixed and reacted in the dechlorination pipeline before entering the dry dust removal system for dust removal.

[0097] In some embodiments of the present application, the blast furnace gas dechlorination and desulfurization system further comprises:

[0098] Regeneration tank;

[0099] Desulfurization oxidation liquid circulation pumping device;

[0100] Injector,

[0101] Among them, a sulfur-rich liquid tank is arranged at the bottom of the hydrogen sulfide absorption tower, and the sulfur-rich liquid tank is connected to the material inlet end of the desulfurization oxidation liquid circulating pumping device. The material outlet end of the desulfurization oxidation liquid circulating pumping device is provided with the injector, and the injector is used to inject the material pumped by the desulfurization oxidation liquid circulating pumping device into the regeneration tank.

[0102] It is easy to understand that the absorption principle of the hydrogen sulfide absorption tower is similar to that of a general absorption tower. As an example, the hydrogen sulfide absorption tower is provided with an absorption section above the sulfur-rich liquid tank, and three packing layers are arranged in the absorption section, each packing layer is composed of a desulfurization liquid initial distributor and a desulfurization liquid redistributor at the top, and a demisting device is also installed at the top of the absorption section to remove sulfur-rich liquid droplets in the desulfurized coal gas before it is discharged from the hydrogen sulfide absorption tower.

[0103] The sulfur-rich liquid enters the sulfur-rich liquid tank under the action of gravity, and the sulfur-rich liquid in the sulfur-rich liquid tank is ejected from the ejector into the regeneration tank under the action of the desulfurization oxidation liquid circulation pumping device. The sulfur-rich liquid is ejected from the ejector to form a jet, and this jet generates a local negative pressure to attract air as an oxidant. At this time, since the two-phase fluid is immediately dispersed at high speed and is in a high-speed turbulent state, the desulfurization liquid is quickly and effectively regenerated and oxidized, thereby implementing step S8, that is, oxidizing the sulfur-rich liquid to obtain a sulfur-containing mixed liquid. After the sulfur-containing mixed liquid enters the regeneration tank, the suspended sulfur particles in the regeneration tank are floated by air to form sulfur foam, and the sulfur foam is separated in the form of overflow, thereby implementing step S9, that is, separating the sulfur element in the sulfur-containing mixed liquid to obtain sulfur element and regenerated desulfurization liquid. Step S10 can then be implemented, that is, the regenerated desulfurization liquid can be used as the desulfurization oxidation liquid to treat the dehydrated coal gas.

[0104] In some embodiments of the present application, the blast furnace gas dechlorination and desulfurization system further includes a sulfur refining system, and the sulfur refining system includes:

[0105] A sulfur foam tank, used for collecting sulfur foam generated in the regeneration tank;

[0106] A filter press, wherein the filter press is connected to the sulfur foam tank via a pumping mechanism;

[0107] The sulfur melting kettle is used for melting the sulfur of the filter cake produced by the filter press.

[0108] In step S9, the sulfur element in the sulfur-containing mixed liquid is separated, and the sulfur foam separated in the form of overflow can enter the sulfur foam tank and then be sent to the filter press. The sulfur element is processed into a filter cake by filtration, and then a high-quality sulfur product is obtained by sulfur melting operation.

[0109] In some embodiments of the present application, the TRT system is connected in parallel with a set of pressure reducing valves.

[0110] The present application will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are intended only to illustrate the present application and are not intended to limit the scope of the present application. The experimental methods for which specific conditions are not specified in the following examples are usually measured according to industry standards. If there is no corresponding industry standard, then the conditions recommended by the manufacturer are followed.

[0111] Example 1

[0112] This embodiment provides a blast furnace gas dechlorination and desulfurization system, the blast furnace gas dechlorination and desulfurization system comprising:

[0113] A preliminary dust removal system, the preliminary dust removal system comprising a gravity dust removal device and a cyclone dust removal device;

[0114] Dechlorination agent injection system;

[0115] A dry dust removal system, wherein the preliminary dust removal system and the dechlorination agent spraying system are both connected to the dry dust removal system;

[0116] A hydrolysis system, connected to the dry dust removal system;

[0117] A TRT system, connected to the hydrolysis system;

[0118] a cooling system, in communication with the TRT system;

[0119] a dehydration system, connected to the cooling system;

[0120] The hydrogen sulfide absorption tower absorbs hydrogen sulfide by spraying the desulfurization oxidation liquid, and the hydrogen sulfide absorption tower is connected to the dehydration system.

[0121] In this embodiment, the dechlorination agent injection system includes:

[0122] Dechlorinating agent raw material warehouse;

[0123] A dechlorinating agent buffer bin is connected to the dechlorinating agent raw material bin via a pumping mechanism;

[0124] A lock bucket is connected to the dechlorinating agent buffer bin through a valve;

[0125] The spray tank is connected with the above-mentioned dust removal system through a valve, and the spray tank is connected with the dry dust removal system.

[0126] In this embodiment, the pumping mechanism is an ash tank pump. The dechlorinating agent raw material bin and the dechlorinating agent buffer bin are loaded with high-pressure nitrogen through the ash tank pump. The dechlorinating agent buffer bin and the lock bucket are connected by a gate valve and a dome valve, and the dechlorinating agent in the dechlorinating agent buffer bin falls into the lock bucket by gravity. The lock bucket is connected to the spray tank by a dome valve, and the dechlorinating agent in the lock bucket enters the spray tank by pressurization.

[0127] In this embodiment, the preliminary dust removal system is connected to the dry dust removal system through a dechlorination pipeline, and the pipe wall of the dechlorination pipeline is provided with an opening for connecting to the spray tank.

[0128] In this embodiment, the dechlorination and desulfurization system of blast furnace gas further includes:

[0129] Regeneration tank;

[0130] Desulfurization oxidation liquid circulation pumping device;

[0131] Injector,

[0132] Among them, a sulfur-rich liquid tank is arranged at the bottom of the hydrogen sulfide absorption tower, and the sulfur-rich liquid tank is connected to the material inlet end of the desulfurization oxidation liquid circulating pumping device. The material outlet end of the desulfurization oxidation liquid circulating pumping device is provided with the injector, and the injector is used to inject the material pumped by the desulfurization oxidation liquid circulating pumping device into the regeneration tank.

[0133] The dechlorination and desulfurization system of blast furnace gas also includes a sulfur refining system, and the sulfur refining system includes:

[0134] A sulfur foam tank, used for collecting sulfur foam generated in the regeneration tank;

[0135] A filter press, wherein the filter press is connected to the sulfur foam tank via a pumping mechanism;

[0136] The sulfur melting kettle is used for melting the sulfur of the filter cake produced by the filter press.

[0137] The TRT system is connected in parallel with a pressure reducing valve group.

[0138] The present embodiment also provides a method for dechlorination and desulfurization of blast furnace gas, and the blast furnace gas parameters involved are as follows: blast furnace gas flow rate is 450000 Nm³ / h, hydrogen chloride content is 80~150 mg / Nm³, hydrogen sulfide content is 30~60 mg / Nm³, carbonyl sulfide content is 80~150 mg / Nm³, temperature before TRT operation is 100~200°C, pressure is 0.2~0.25MPa, temperature after TRT operation is 40~60°C, and pressure is 15kPa.

[0139] The steps include:

[0140] After loading 30tBKDCl-1 of dechlorinating agent into the dechlorinating agent raw material bin, the dechlorinating agent is transported to the dechlorinating agent buffer bin through the ash tank pump at the outlet of the dechlorinating agent powder bin by pneumatic conveying;

[0141] The dechlorinating agent buffer bin starts to feed the lock hopper. After the feeding is completed, the pneumatic dome valve between the lock hopper and the dechlorinating agent buffer bin is closed. The dome valve between the lock hopper and the spray tank is opened, and the lock hopper starts to feed the spray tank. After the feeding is completed, the dome valve connecting the two is closed;

[0142] Detect the HCl content of blast furnace gas, record it as X1, and calculate the hourly dechlorination agent injection amount by X1;

[0143] After the blast furnace gas is subjected to gravity dust removal and cyclone dust removal, the dechlorination agent injection operation is started according to the dechlorination agent injection amount per hour to obtain pre-dechlorinated gas;

[0144] The pre-dechlorinated coal gas is subjected to dry dust removal treatment through a bag filter to obtain dechlorinated coal gas. According to calculation, the HCl content of the dechlorinated coal gas is less than 5 mg / Nm³, while the HCl content of the blast furnace gas is 80-150 mg / Nm³, which shows that the dechlorination effect is significant;

[0145] Then, the dechlorinated coal gas is subjected to hydrolysis treatment, TRT operation, cooling, and dehydration to obtain dehydrated coal gas;

[0146] Prepare a desulfurization oxidation liquid and add it into the sulfur-rich liquid tank, wherein the pH of the desulfurization oxidation liquid is 8-9, the pH of the desulfurization oxidation liquid is adjusted by adding sodium carbonate or sodium hydroxide, and the desulfurization oxidation liquid contains 3g / L of DSH catalytic oxidant;

[0147] Start the desulfurization oxidation liquid circulation pumping device to transport the desulfurization oxidation liquid in the sulfur-rich liquid tank to the ejector, and then the ejector will eject the desulfurization oxidation liquid to the regeneration tank;

[0148] The desulfurized oxidized liquid in the regeneration tank enters the top of the hydrogen sulfide absorption tower for desulfurization operation to obtain desulfurized coal gas and sulfur-rich liquid, the hydrogen sulfide concentration in the desulfurized coal gas is ≤10mg / Nm³, the sulfur-rich liquid flows into the sulfur-rich liquid tank, is oxidized and regenerated by air during the injection process of the ejector, and then enters the regeneration tank as the desulfurized oxidized liquid and circulates back to the top of the hydrogen sulfide absorption tower for circulation operation;

[0149] The suspended sulfur particles in the regeneration tank are floated by air to form sulfur foam, which is separated in the form of overflow, thereby implementing step S9, that is, separating the sulfur element in the sulfur-containing mixed solution to obtain sulfur element and regenerated desulfurization liquid. Then it enters the sulfur foam tank and is sent to the filter press to process the sulfur element into a filter cake through filtration, and then obtains a sulfur product with a purity of more than 98% through sulfur melting.

[0150] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be understood as a rigid limitation on the scope of the present application; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numerical values ​​within the range. For example, the range description from 1 to 6 should be considered to have specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.

[0151] In the present application, in the absence of any contrary description, the directional words used, such as "upper" and "lower", are specifically the directions of the drawings in the accompanying drawings. In addition, in the description of the present application specification, the terms "including", "comprising", etc. refer to "including but not limited to". Moreover, the terms "including", "comprising" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or equipment. In the absence of further restrictions, the elements defined by the sentence "including..." do not exclude the existence of other identical elements in the process, method, article or equipment including the elements. In this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. In this article, "and / or" describes the association relationship of associated objects, indicating that there can be three relationships, for example, A and / or B, which can represent: A exists alone, A and B exist at the same time, and B exists alone. For the association relationship of more than three associated objects described by "and / or", it means that any one of the three associated objects can exist alone, or any at least two of them can exist at the same time. For example, for A, and / or B, and / or C, it can mean that any one of A, B, and C exists alone, or any two of them exist at the same time, or three of them exist at the same time. In this article, "at least one" means one or more, and "multiple" means two or more. "At least one", "at least one of the following" or similar expressions refer to any combination of these items, including any combination of single items or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c" can all mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0152] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A method for dechlorinating and desulfurizing blast furnace gas, It is characterized in that The dechlorination and desulfurization method of blast furnace gas comprises the following steps: Gravity dust removal and cyclone dust removal are performed on blast furnace gas to obtain pre-dust-removed gas; spraying a dechlorinating agent into the pre-dust-removed coal gas to dechlorinate the blast furnace gas to obtain the pre-dechlorinated coal gas; performing dry dust removal treatment on the pre-dechlorinated coal gas to obtain dechlorinated coal gas; hydrolyzing the dechlorinated coal gas to obtain hydrolyzed coal gas; Using the hydrolyzed coal gas to drive a TRT device to perform power generation operations to obtain post-TRT coal gas; Cooling and dehydrating the post-TRT coal gas to obtain dehydrated coal gas; The dehydrated coal gas is treated with a desulfurization oxidizing liquid to convert hydrogen sulfide in the dehydrated coal gas into elemental sulfur to obtain desulfurized coal gas and sulfur-rich liquid; The blast furnace gas flow rate is 450000 Nm³ / h, the hydrogen chloride content is 80-150 mg / Nm³, the hydrogen sulfide content is 30-60 mg / Nm³, and the carbonyl sulfide content is 80-150 mg / Nm³; The step of spraying a dechlorinating agent into the pre-dust-removed coal gas to dechlorinate the blast furnace gas to obtain the pre-dechlorinated coal gas comprises: After the dechlorinating agent is loaded into the dechlorinating agent raw material bin, the dechlorinating agent is transported from the outlet of the dechlorinating agent raw material bin to the dechlorinating agent buffer bin by the ash tank pump using high-pressure nitrogen, and the nitrogen pressure is 200~300kPa; The dechlorinating agent buffer bin starts to feed the lock hopper. After the feeding is completed, the pneumatic dome valve between the lock hopper and the dechlorinating agent buffer bin is closed, and the dome valve between the lock hopper and the spray tank is opened. The lock hopper starts to feed the spray tank. After the feeding is completed, the dome valve connecting the two is closed; The hourly dechlorinating agent injection amount is calculated according to the HCl content of the blast furnace gas; the dechlorinating agent injection operation is started according to the hourly dechlorinating agent injection amount to obtain pre-dechlorinated gas, wherein the injection tank is pressurized and the pressure of the injection tank is more than 30 kPa higher than the pressure at the blast furnace gas supply end. The dechlorinating agent in the lock hopper enters the injection tank under pressure, and the pressure difference between the lock hopper and the injection tank is 5~50 kPa.

2. The method for dechlorination and desulfurization of blast furnace gas according to claim 1, It is characterized in that The dechlorinating agent is BKDC1-1 dechlorinating agent.

3. The method for dechlorination and desulfurization of blast furnace gas according to claim 1, It is characterized in that The desulfurization oxidation liquid is an alkaline solution containing a DSH catalytic oxidant.

4. The method for dechlorination and desulfurization of blast furnace gas according to claim 1, It is characterized in that The dechlorination and desulfurization method of blast furnace gas also includes the following steps: performing oxidation treatment on the sulfur-rich liquid to obtain a sulfur-containing mixed liquid; Separating sulfur from the sulfur-containing mixed liquid to obtain sulfur and regenerated desulfurized liquid; The dehydrated coal gas is treated by using the regenerated desulfurization liquid as the desulfurization oxidation liquid.

5. A system for dechlorinating and desulfurizing blast furnace gas according to any one of claims 1 to 4, It is characterized in that The dechlorination and desulfurization system of blast furnace gas comprises: A preliminary dust removal system, the preliminary dust removal system comprising a gravity dust removal device and a cyclone dust removal device; Dechlorination agent injection system; A dry dust removal system, wherein the preliminary dust removal system and the dechlorination agent spraying system are both connected to the dry dust removal system; A hydrolysis system, connected to the dry dust removal system; A TRT system, connected to the hydrolysis system; a cooling system, in communication with the TRT system; a dehydration system, connected to the cooling system; The hydrogen sulfide absorption tower absorbs hydrogen sulfide by spraying the desulfurization oxidation liquid, and the hydrogen sulfide absorption tower is connected to the dehydration system.

6. The dechlorination and desulfurization system for blast furnace gas according to claim 5, It is characterized in that The dechlorinating agent injection system comprises: Dechlorinating agent raw material warehouse; A dechlorinating agent buffer bin is connected to the dechlorinating agent raw material bin via a pumping mechanism; A lock bucket is connected to the dechlorinating agent buffer bin through a valve; The spray tank is connected with the above-mentioned dust removal system through a valve, and the spray tank is connected with the dry dust removal system.

7. The dechlorination and desulfurization system for blast furnace gas according to claim 6, It is characterized in that The preliminary dust removal system is connected to the dry dust removal system through a dechlorination pipeline, and the pipe wall of the dechlorination pipeline is provided with an opening for connecting to the spray tank.

8. The dechlorination and desulfurization system for blast furnace gas according to claim 5, It is characterized in that The dechlorination and desulfurization system of blast furnace gas also includes: Regeneration tank; Desulfurization oxidation liquid circulation pumping device; Injector, Among them, a sulfur-rich liquid tank is arranged at the bottom of the hydrogen sulfide absorption tower, and the sulfur-rich liquid tank is connected to the material inlet end of the desulfurization oxidation liquid circulating pumping device. The material outlet end of the desulfurization oxidation liquid circulating pumping device is provided with the injector, and the injector is used to inject the material pumped by the desulfurization oxidation liquid circulating pumping device into the regeneration tank.

9. The dechlorination and desulfurization system for blast furnace gas according to claim 8, It is characterized in that The dechlorination and desulfurization system of blast furnace gas also includes a sulfur refining system, and the sulfur refining system includes: A sulfur foam tank, used for collecting sulfur foam generated in the regeneration tank; A filter press, wherein the filter press is connected to the sulfur foam tank via a pumping mechanism; The sulfur melting kettle is used for melting the sulfur of the filter cake produced by the filter press.

10. The blast furnace gas dechlorination and desulfurization system according to claim 5, It is characterized in that The TRT system is connected in parallel with a pressure reducing valve group.

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