Resource utilization method and equipment for coal gas desulfurization solid waste

Abstract

The invention discloses a resource utilization method and equipment for coal gas desulfurization solid waste. According to the method, a coal gas desulfurization solid waste treatment process and a waste acid regeneration process are coupled into a whole. The equipment comprises a waste acid regeneration system for recycling the waste acid solution generated by the strip steel cold rolling pickling unit and a treatment tank for carrying out sealed soaking treatment on the coal gas desulfurization solid waste and the waste acid solution. According to the invention, the problem of desulfurization solid waste disposal is solved by utilizing the existing environment-friendly facility acid regeneration system of the long-process iron and steel enterprise, the additional investment is small, harmless disposal of solid waste in the iron and steel enterprise and effective recovery of iron resources are realized, and the method has remarkable technical economy and environmental benefits. According to the method disclosed by the invention, organic matters in the coal gas desulfurization solid waste are subjected to high-temperature decomposition in the roasting furnace while iron elements are recycled, so that the problem of environmental pollution is solved, sulfur elements are separated from internal circulation through ways of flue gas purification, desilicication waste and the like, and no negative influence is brought to main flow production of steel.

Description

Technical Field

[0001] The present invention relates to the technical field of solid waste resource utilization, and in particular to a method and equipment for resource utilization of coal gas desulfurization solid waste. Background Art

[0002] The coke oven gas activated iron oxide dry desulfurization process is a common coke oven gas secondary purification method used by steel companies. This process produces a gas desulfurization solid waste byproduct. On the one hand, this solid waste contains a large amount of ferrous resources and has the potential to be returned to the internal production of steel companies. On the other hand, it has the characteristics of high harmful S elements and small particle size. During the use of production processes such as sintering and converters, it is easy to cause metallurgical product quality problems such as deterioration of material permeability and sulfur increase in molten steel. The traditional disposal method of this solid waste is mainly to send it to cement plants, thermal power plants and other industries for high-temperature incineration and coordinated disposal. Although it solves the problem of harmless disposal of solid waste, it also causes waste of resources in steel companies.

[0003] Patent CN1635057A discloses a method for recovering sulfur from waste iron oxide desulfurizer in coal gas, which mainly uses toluene as raw material and utilizes process facilities such as desulfurization tower, three-way valve, circulation pump, crystallization tank, precipitation tank, etc., and uses hot toluene to extract elemental sulfur, so as to achieve the regeneration of iron oxide desulfurizer and its recycling in the activated iron oxide dry desulfurization process. Although this method has a good treatment effect, it also has problems such as high investment cost and high regeneration cost.

[0004] The acid regeneration (Ruthner) process is a common supporting production process for the pickling production line of domestic cold-rolled thin plate plants. It mainly regenerates the waste acid produced by strip pickling into hydrochloric acid through oxidation roasting and reuses it in the pickling process, thereby saving a large amount of hydrochloric acid consumption and recovering iron resources in the waste acid liquid. It has good technical and economic benefits.

[0005] Therefore, the applicant considered the characteristics of coal gas desulfurization solid waste and the problems existing in the disposal process, and proposed a coordinated disposal method for coal gas desulfurization solid waste. Summary of the invention

[0006] In order to overcome the shortcomings of the above-mentioned prior art, the purpose of the present invention is to provide a method and equipment for resource utilization of coal gas desulfurization solid waste, solve the problems of resource waste and high treatment cost in the disposal process of coal gas desulfurization solid waste, and realize the resource recovery and environmentally friendly disposal of desulfurization solid waste by using the coal gas desulfurization solid waste for the acid regeneration process.

[0007] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0008] A method for resource utilization of coal gas desulfurization solid waste, which couples the coal gas desulfurization solid waste disposal process with the waste acid regeneration process. The coal gas desulfurization solid waste is a by-product of the coke oven gas activated iron oxide dry desulfurization process; the waste acid liquid in the waste acid regeneration process is the waste acid liquid generated by the pickling of strip steel in the cold rolling thin plate production line.

[0009] The principle of the coke oven gas activated iron oxide dry desulfurization process is to use Fe2O3-based adsorbents to convert and remove H2S in the coke oven gas. The following reactions mainly occur:

[0010] Fe2O3+H2S=2FeO+H2O+S Formula 1;

[0011] FeO+H2S=FeS+H2O Formula 2;

[0012] Among them, iron oxides and sulfur are regularly replaced and discharged to form desulfurization solid waste. At the same time, during the desulfurization process, Fe2O3 adsorbent will also adsorb trace amounts of tar, phenol and other organic matter in coke oven gas. Therefore, the coal gas desulfurization solid waste mainly contains FeO, FeS, S, tar, phenol, etc., and also includes unreacted Fe2O3.

[0013] Waste acid regeneration system is commonly used in the cold-rolled strip pickling process, using hydrochloric acid to clean the surface oxide scale of hot-rolled plates. After pickling, the waste acid liquid enters the waste acid tank and is first sprayed into the pre-concentrator, where it exchanges heat with the flue gas discharged from the double cyclone dust collector to recover heat and evaporate part of the water, increase the solution concentration, and then enters the roasting furnace. Through high-temperature roasting, solutes such as FeCl3 in the waste acid liquid are converted into Fe2O3 and HCl. The main reactions are as follows:

[0014] 2FeCl3+3H2O=Fe2O3+6HCl Formula 3;

[0015] The Fe2O3 is cooled to iron oxide powder and discharged through the double cyclone dust collector and iron oxide powder collection system to form iron oxide powder, which can be returned to sintering for recycling iron resources. The HCl-containing gas produced by high-temperature roasting returns to the pre-concentrator for heat exchange and enters the absorption tower. The spray device in the tower absorbs HCl as regenerated acid and enters the regenerated acid tank, and participates in the flue gas after purification to meet the emission standards.

[0016] The technical idea of ​​the present invention is to use the process characteristics of the existing waste acid regeneration system to dispose of the coal gas desulfurization solid waste, introduce the waste acid liquid into the disposal tank to react with the coal gas desulfurization solid waste, and the specific reaction is as follows:

[0017] Fe2O3+6HCl=2FeCl3+3H2O Formula 4;

[0018] FeO+2HCl=FeCl2+H2O Formula 5;

[0019] FeS+2HCl=FeCl2+H2S Formula 6;

[0020] 4FeCl2+O2+4HCl=4FeCl3+2H2O Formula 7;

[0021] H2S(aq.)=H2S(g) Formula 8;

[0022] H2S+O2=H2O+S Formula 9;

[0023] H2S+O2=H2O+SO2 Formula 10;

[0024] SO2+H2O=H2SO3 Formula 11;

[0025] H2SO3+O2=H2SO4 Formula 12;

[0026] 3H2SO4+2FeCl3=Fe2(SO4)3+6HCl Formula 13;

[0027] After leaching the waste acid, the iron element enters the solution and is mainly converted into FeCl3. For the S element, part of it volatilizes into the gas phase of the disposal tank (as shown in Formula 8); part of it reacts as shown in Formula 9 to produce elemental S, which exists in the solid phase like the original S in the coal gas desulfurization solid waste; the remaining part enters the waste acid and there are multiple conversion modes, as shown in Formulas 10 to 13, and it is finally mainly converted into sulfate.

[0028] After leaching, the gas phase in the disposal tank contains not only H2S, but also organic matter such as tar volatilized from the solid waste of coal gas desulfurization. Therefore, in the disposal process, the gas phase in the disposal tank is first introduced into the roaster gas system and burned. In this process, H2S will be converted into SO3 gas and enter the regeneration acid in the form of H2SO4 through the absorption tower with the flue gas.

[0029] The liquid phase in the disposal tank has similar properties to the waste acid in the waste acid tank. The two waste acid liquids can be disposed of together in the pre-concentrator and other waste acid regeneration process. The sulfate in the liquid phase of the disposal tank is converted into Fe2O3 and H2SO4 during the disposal process. Fe2O3 enters the iron oxide powder and H2SO4 enters the regeneration acid.

[0030] There will be a small amount of solid residue that cannot be completely dissolved in the disposal tank, mainly elemental sulfur and acid insoluble matter. This part of the solid can be cleaned regularly after the process has been cycled many times. The cleaned waste can be recycled together with the elemental sulfur produced in the coking wastewater treatment process such as the vacuum potassium carbonate method.

[0031] After the solid waste from coal gas desulfurization is treated, the waste acid regeneration system is restored to treat the waste acid liquid separately.

[0032] After coupling the desulfurization solid waste disposal with the waste acid regeneration process, the main impact on the waste acid regeneration process is that the sulfuric acid content in the regenerated acid solution of the waste acid regeneration circulation system will increase to a certain extent. On the one hand, sulfuric acid is also a strong acid, which is completely ionized and will not affect the acidity of the regenerated acid solution. On the other hand, this problem will naturally be solved by the waste acid desiliconization system of the waste acid regeneration system itself. The waste acid desiliconization system is mainly used to deal with the problem that the alloy elements such as silicon in the steel plate itself produce a small amount of solids after multiple cycles, which is easy to block the pipeline. These substances that are not easily soluble in acid can be eliminated by flocculation and precipitation. Sulfate ions are larger in volume than chloride ions and are more likely to participate in flocculation reactions. Therefore, in the normal waste acid desiliconization process, a large amount of sulfate ions enter the solid phase and are discharged with the desiliconization waste. In addition, there is also a process of regularly discharging waste acid in the form of acidic wastewater in the waste acid desiliconization process. Therefore, there is no need to worry about the problem of cyclic enrichment of sulfuric acid in the waste acid regeneration main system.

[0033] The above technical ideas can ensure the normal operation of the coal gas desulfurization solid waste disposal and waste acid regeneration system, recover valuable resources without adversely affecting the quality of steel plates and the environment.

[0034] Based on the above technical ideas, the technical solution of the present invention specifically includes the following steps:

[0035] 1) Using part of the waste acid liquid as a soaking agent, the coal gas desulfurization solid waste and the waste acid liquid are mixed and soaked in a closed state; the coal gas desulfurization solid waste is a by-product of the coke oven gas activated iron oxide dry desulfurization process; the waste acid liquid is the waste acid liquid generated by the pickling of strip steel in the cold-rolled thin plate production line;

[0036] 2) introducing the gas generated after the soaking treatment together with the coal gas used as fuel into the roasting furnace of the waste acid regeneration system for combustion treatment;

[0037] 3) sending the liquid generated after the soaking treatment together with the part of the waste acid liquid that is not used as the soaking agent into the pre-concentrator of the waste acid regeneration system, and processing through the roasting furnace, double cyclone dust collector and absorption tower of the waste acid regeneration system to recover the iron oxide powder and the regenerated acid;

[0038] 4) Regularly clean and remove the solids generated after the soaking treatment.

[0039] Furthermore, in the step 1), the chemical composition of the coal gas desulfurization solid waste includes: the mass percentage of TFe is 60-70%, and the mass percentage of S is 15-25%; the physical properties of the coal gas desulfurization solid waste are: the mass of particles with a particle size of less than 5 cm is ≥95%, and the mass of particles with a particle size of less than 2.36 cm is ≥60%.

[0040] Furthermore, in step 1), the waste acid solution contains HCl, and H +The ion concentration is 4-6 mol / L.

[0041] Furthermore, in the step 1), before the soaking treatment, the coal gas desulfurization solid waste can be ground, sieved through a 30-mesh sieve, the undersize is taken for the soaking treatment, and the oversize is ground again; in the soaking treatment, the soaking temperature is 40-50° C., and the soaking time is 60-120 min. Grinding the coal gas desulfurization solid waste and then soaking it can effectively improve the efficiency of the soaking treatment and the leaching effect.

[0042] Furthermore, in the step 1), the mass ratio of the coal gas desulfurization solid waste to the waste acid liquid used for the soaking treatment is 1:6 to 10. According to the content of the components in the coal gas desulfurization solid waste and the waste acid liquid and their reaction process, the mass ratio of the coal gas desulfurization solid waste to the waste acid liquid can be obtained, the full reaction of each component in the coal gas desulfurization solid waste and the waste acid liquid is maintained, and the treatment efficiency of the coal gas desulfurization solid waste is improved.

[0043] Furthermore, in step 2), the coal gas is a mixture of blast furnace gas, converter gas, coke oven gas or more. The coal gas used in this technical solution is the coal gas used in the conventional operation of the waste acid regeneration process, and no additional coal gas and equipment are required.

[0044] Furthermore, in the step 2), the gas generated after the soaking treatment is introduced into the roasting furnace through a fan and burned together with the coal gas, wherein the air supply volume of the fan is 2-5% of the volume of the coal gas, and the roasting furnace temperature is increased from the conventional 550-650°C to 800-850°C. After the combustion treatment is completed, the roasting furnace temperature is reduced to the conventional 550-650°C.

[0045] The normal operating temperature of the roasting furnace is 550-650℃. When treating coal gas desulfurization solid waste, raising the temperature to above 800℃ can avoid the temperature range of dioxin production and directly use high temperature to convert organic matter into harmless substances such as CO2 and H2O. The main reason for not using temperatures above 850℃ is energy saving.

[0046] Furthermore, in the step 3), in the mixed liquid sent to the waste acid regeneration system, the volume percentage of the liquid produced after the soaking treatment is 5-30%, and the volume percentage of the part of the waste acid liquid not used as the soaking agent is 70-95%.

[0047] Furthermore, in the step 3), the regenerated acid obtained contains HCl and H2SO4, and the sulfate in the H2SO4 is discharged through the waste acid desiliconization system in the waste acid regeneration system; in the step 4), the solid generated after the soaking treatment is cleaned regularly, and the elemental sulfur is recovered by the vacuum potassium carbonate method.

[0048] Furthermore, the iron oxide powder can be returned for sintering.

[0049] A resource utilization device for coal gas desulfurization solid waste designed to achieve the above method comprises a waste acid regeneration system for recovering waste acid liquid generated by a strip cold rolling pickling unit, wherein the waste acid regeneration system is mainly composed of a waste acid tank, a pre-concentrator, a roasting furnace, a double cyclone dust collector, an absorption tower, a regenerated acid tank, an iron oxide powder collection system, a flue gas purification system, and a waste acid desiliconization system; and further comprises a disposal tank for sealed immersion treatment of coal gas desulfurization solid waste and waste acid liquid, wherein a desulfurization solid waste inlet, a waste acid inlet, a gas outlet, and a liquid outlet are respectively provided on the disposal tank, wherein the desulfurization solid waste inlet is connected to the discharge end of the desulfurization solid waste grinding system, the waste acid inlet is connected to the first output end of the waste acid tank, the gas outlet is connected to the burner inlet of the roasting furnace, and the liquid outlet is connected to the mixed liquid inlet of the pre-concentrator.

[0050] Preferably, the desulfurization solid waste grinding system includes a ball mill, a screening machine and a storage yard, the discharge port of the ball mill is connected to the feed port of the screening machine, the screened material outlet of the screening machine is connected to the return port of the ball mill, the screened material outlet of the screening machine is connected to the feed end of the storage yard, and the discharge end of the storage yard is connected to the desulfurization solid waste inlet of the disposal tank.

[0051] Preferably, the screening machine uses a 30-mesh screen.

[0052] Compared with the prior art, the present invention has the following beneficial effects:

[0053] The resource utilization method and equipment of coal gas desulfurization solid waste provided by the present invention utilize the acid regeneration system of existing environmental protection facilities of long-process steel enterprises to solve the problem of desulfurization solid waste disposal, with small additional investment, and realize the harmless disposal of solid waste and effective recovery of ferrous resources within the steel enterprise, which has significant technical, economic and environmental benefits.

[0054] The method of the present invention not only recovers iron, but also decomposes organic matter in the coal gas desulfurization solid waste at high temperature in the roasting furnace, thereby solving the environmental pollution problem. The sulfur element is separated from the internal circulation through flue gas purification, desiliconization waste and other means, and has no negative impact on the main steel production process.

[0055] The waste acid regeneration system in the present invention has a perfect material circulation capacity when the coal gas desulfurization solid waste is not disposed. Sulfuric acid is also a strong acid and is completely ionized when mixed with hydrochloric acid. It does not affect the acidity of the regenerated acid solution, nor does it affect the pickling quality of the steel plate. It does not rule out the possibility that trace amounts of sulfate ions remain on the surface of the steel plate, but in the subsequent alkaline washing and rinsing process of the steel plate, the sulfate ions become soluble and are discharged with the alkaline washing and rinsing liquid, which does not affect the subsequent processing and surface quality of the steel plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1It is a connection diagram of the resource utilization system of coal gas desulfurization solid waste in the present invention. DETAILED DESCRIPTION

[0057] In order to better explain the present invention, the main contents of the present invention are further explained below in conjunction with the drawings and specific embodiments, but the contents of the present invention are not limited to the following embodiments.

[0058] like Figure 1 As shown, the present invention provides a resource utilization device for coal gas desulfurization solid waste, including a waste acid regeneration system for recovering waste acid liquid generated by a strip cold rolling pickling unit, and the waste acid regeneration system mainly includes: a waste acid tank, a pre-concentrator, a roasting furnace, a double cyclone dust collector, an absorption tower, a regenerated acid tank, an iron oxide powder collection system, a flue gas purification system, and a waste acid desiliconization system.

[0059] The above-mentioned resource utilization equipment for coal gas desulfurization solid waste also includes a disposal tank for sealed immersion treatment of coal gas desulfurization solid waste and waste acid liquid, and the disposal tank is respectively provided with a desulfurization solid waste inlet, a waste acid inlet, a gas outlet and a liquid outlet, the desulfurization solid waste inlet is connected to the discharge end of the desulfurization solid waste grinding system, the waste acid inlet is connected to the first output end of the waste acid tank, the gas outlet is connected to the burner inlet of the roasting furnace, and the liquid outlet is connected to the mixed liquid inlet of the pre-concentrator.

[0060] The desulfurization solid waste grinding system includes a ball mill, a screening machine and a storage yard. After the coal gas desulfurization solid waste is ground and screened, it is stored in the storage yard; the discharge port of the ball mill is connected to the feed port of the screening machine, the screened material outlet of the screening machine is connected to the return port of the ball mill, the screened material outlet of the screening machine is connected to the feed end of the storage yard, and the discharge end of the storage yard is connected to the desulfurization solid waste inlet of the disposal tank.

[0061] The screening machine adopts a 30-mesh screen.

[0062] The waste acid tank is used to store waste acid liquid from the strip cold rolling pickling unit, and its input end is connected to the waste acid outlet of the strip cold rolling pickling unit, and the second output end is connected to the waste acid inlet of the pre-concentrator.

[0063] The pre-concentrator is provided with a concentrated waste liquid outlet, which is connected to the concentrated waste liquid inlet of the roasting furnace. The pre-concentrator uses the high-temperature flue gas generated by the roasting furnace for heat exchange to concentrate the liquid from the disposal tank and the waste acid liquid from the waste acid tank to generate concentrated waste liquid.

[0064] The roasting furnace is provided with an iron oxide powder discharge port and a flue gas outlet; the iron oxide powder discharge port is connected to the feed port of the iron oxide powder collection system; the flue gas outlet of the roasting furnace is connected in series with the double cyclone dust collector, the pre-concentrator, the absorption tower, and the flue gas purification system in sequence. The burner inlet of the roasting furnace is also connected to the gas pipeline. The roasting furnace roasts the concentrated waste liquid from the pre-concentrator to produce iron oxide powder and high-temperature flue gas. The iron oxide powder is collected by the iron oxide powder collection system. The high-temperature flue gas is dedusted by the double cyclone dust collector and then enters the pre-concentrator for heat exchange and cooling. The cooled flue gas enters the absorption tower, and the spray device absorbs HCl in the flue gas as regenerated acid. The remaining flue gas is purified by the flue gas purification system and then discharged.

[0065] The precipitate outlet of the double cyclone dust collector is connected to the roasting furnace. The double cyclone dust collector removes dust from the high-temperature flue gas generated by the roasting furnace and returns the collected precipitate to the roasting furnace.

[0066] The absorption tower is provided with a regeneration acid liquid outlet, which is connected to the regeneration acid liquid inlet of the regeneration acid tank, so as to transfer the regeneration acid in the absorption tower to the regeneration acid tank for storage.

[0067] The regenerated acid liquid outlet of the regenerated acid tank is connected to the strip cold rolling pickling unit, and the regenerated acid is reused in the cold rolling pickling unit.

[0068] The spent acid desiliconization system is used to periodically perform desiliconization treatment on the spent acid discharged from the spent acid regeneration system.

[0069] The above equipments are all commonly used in the chemical industry, and their specific structures will not be described in detail.

[0070] A method for resource utilization of coal gas desulfurization solid waste implemented by the above-mentioned coal gas desulfurization solid waste resource utilization equipment comprises the following steps:

[0071] 1) The coal gas desulfurization solid waste is sent to a ball mill for grinding for 15 to 30 minutes. After grinding, it is screened by a screening machine. The part above the 30-mesh screen is returned to the ball mill for further grinding, and the part below the 30-mesh screen is sent to a storage yard for storage and standby use;

[0072] The chemical composition characteristics of coal gas desulfurization solid waste (dry basis) are: 60%≤TFe≤70%; 15%≤S≤25%; the remainder is O element combined with Fe element, various organic matter and other inevitable acid-insoluble impurity elements. The particle size characteristics are that the mass of particles below 5 cm is ≥95%, and the mass of particles below 2.36 cm is ≥60%.

[0073] Add the coal gas desulfurization solid waste from the storage yard into the disposal tank, cover and seal it, add the waste acid liquid in the waste acid tank of the waste acid regeneration system into the disposal tank, and the solid-liquid ratio is 1:6-10; soak the coal gas desulfurization solid waste in the waste acid liquid, the soaking temperature is 40-50℃, and the soaking time is 60-120min; the waste acid liquid is mainly waste hydrochloric acid, and the H+ ion concentration of the acid liquid is 4-6mol / L.

[0074] 2) Start the waste acid regeneration system and run it normally for 30 to 60 minutes, then increase the roasting furnace temperature from 550 to 650°C to 800 to 850°C;

[0075] The gas generated after immersion treatment in the disposal tank is introduced into the roaster gas system by a fan and burned together with the coal gas. The air volume is 2-5% of the coal gas volume and the disposal time is 2-4 minutes. After the upper gas in the disposal tank is replaced, the roaster temperature is gradually reduced to 550-650°C. The coal gas is a mixture of one or more of blast furnace gas, converter gas and coke oven gas.

[0076] 3) reducing the amount of liquid added from the waste acid tank to the pre-concentrator to 70-95% of the normal amount, and at the same time introducing the liquid produced after the soaking treatment in the disposal tank into the pre-concentrator to compensate for the corresponding reduction in the amount added from the waste acid tank, so that the total amount of liquid added remains normal, and the waste acid regeneration system is processed by the roasting furnace, double cyclone dust collector, and absorption tower to recover iron oxide powder and regenerated acid;

[0077] After the liquid in the disposal tank is treated, stop adding liquid from the disposal tank, restore the amount of liquid added from the waste acid tank to the pre-concentrator to the normal amount, and keep the waste acid regeneration system running normally for more than 30 minutes, and then return to step 2) to re-treat the next round of gas desulfurization solid waste or keep the waste acid regeneration system running normally for waste acid treatment.

[0078] 4) The solids generated after the soaking treatment are cleaned regularly and the elemental sulfur is recovered by the vacuum potassium carbonate method.

[0079] The process of the present invention is further described below in conjunction with Examples 1 to 3. Examples 1 to 3 all adopt the above-mentioned method for resource utilization of solid waste from coal gas desulfurization.

[0080] Embodiment 1:

[0081] The relevant parameters in this embodiment are as follows:

[0082] The chemical composition characteristics of coal gas desulfurization solid waste (dry basis) are: TFe 68.4%; S 15.7%; the remainder is O element combined with Fe element, various organic matter and other inevitable acid-insoluble impurity elements. The particle size characteristics are that the mass proportion of particles below 5 cm accounts for 95.8%, and the mass proportion of particles below 2.36 cm accounts for 63.1%.

[0083] The H+ ion concentration of the waste acid solution is 4.3 mol / L.

[0084] In step 1), the grinding time is 15 minutes, the masses of the coal gas desulfurization solid waste and the waste acid liquid used for the soaking treatment are 500 kg and 3000 kg, the soaking temperature is 40° C., and the soaking time is 60 minutes;

[0085] In step 2), the acid regeneration system facility is turned on and operated for 30 minutes, and then the roasting furnace is raised to 800°C; the fan air volume is 2% of the gas volume, and the combustion treatment time is 2 minutes; after the combustion treatment is completed, the roasting furnace temperature is gradually reduced to 560°C; the gas adopts the converter gas used in the waste acid regeneration system under normal conditions.

[0086] In step 3), the amount of liquid produced after the soaking treatment is injected into the mixed liquid sent to the waste acid regeneration system is 0.15 L / s, and the amount of the waste acid liquid not used as the soaking agent is injected into the mixed liquid is 0.35 L / s.

[0087] After the liquid generated after the soaking treatment is completed, the injection rate from the waste acid tank to the pre-concentrator will be adjusted back to 0.5L / s, and the acid regeneration system will be kept in normal operation for 40 minutes before the next round of operation.

[0088] Embodiment 2:

[0089] The relevant parameters in this embodiment are as follows:

[0090] The chemical composition characteristics of coal gas desulfurization solid waste (dry basis) are: TFe 65.3%; S2 0.5%; the remainder is O element combined with Fe element, various organic matter and other inevitable acid-insoluble impurity elements. The particle size characteristics are that the mass proportion of particles below 5 cm accounts for 96.8%, and the mass proportion of particles below 2.36 cm accounts for 72.1%.

[0091] The H+ ion concentration of the waste acid solution is 5.1 mol / L.

[0092] In step 1), the grinding time is 20 minutes, the masses of the coal gas desulfurization solid waste and the waste acid liquid used for the soaking treatment are 1000 kg and 8000 kg, the soaking temperature is 45° C., and the soaking time is 90 minutes;

[0093] In step 2), the acid regeneration system facility is turned on and operated for 45 minutes, and then the roasting furnace is raised to 820°C; the fan air volume is 3% of the gas volume, and the combustion treatment time is 3 minutes; after the combustion treatment is completed, the roasting furnace temperature is gradually reduced to 600°C; the gas adopts the converter gas used in the waste acid regeneration system under normal conditions.

[0094] In step 3), the amount of liquid produced after the soaking treatment is injected into the mixed liquid sent to the waste acid regeneration system is 0.12 L / s, and the amount of the waste acid liquid not used as the soaking agent is injected into the mixed liquid is 0.68 L / s.

[0095] After the liquid generated after the soaking treatment is completed, the injection rate from the waste acid tank to the pre-concentrator will be adjusted back to 0.8L / s, and the acid regeneration system will be kept running normally for 50 minutes before the next round of operation.

[0096] Embodiment 3:

[0097] The relevant parameters in this embodiment are as follows:

[0098] The chemical composition characteristics of coal gas desulfurization solid waste (dry basis) are: TFe 63.1%; S24.2%; the remainder is O element combined with Fe element, various organic matter and other inevitable acid-insoluble impurity elements. The particle size characteristics are that the mass proportion of particles below 5 cm accounts for 97.7%, and the mass proportion of particles below 2.36 cm accounts for 85.9%.

[0099] The H+ ion concentration of the waste acid solution is 5.8 mol / L.

[0100] In step 1), the grinding time is 30 minutes, the masses of the coal gas desulfurization solid waste and the waste acid liquid used for the soaking treatment are 1200 kg and 12000 kg, the soaking temperature is 50° C., and the soaking time is 120 minutes;

[0101] In step 2), the acid regeneration system facility is turned on and operated for 60 minutes, and then the roasting furnace is increased to 850°C; the fan air volume is 4% of the gas volume, and the combustion treatment time is 4 minutes; after the combustion treatment is completed, the roasting furnace temperature is gradually reduced to 630°C; the gas adopts the converter gas used in the waste acid regeneration system under normal conditions.

[0102] In step 3), the amount of liquid produced after the soaking treatment is injected into the mixed liquid sent to the waste acid regeneration system is 0.1 L / s, and the amount of the waste acid liquid not used as the soaking agent is injected into the mixed liquid is 0.9 L / s.

[0103] After the liquid generated after the soaking treatment is completed, the injection rate from the waste acid tank to the pre-concentrator will be adjusted back to 1.0L / s, and the acid regeneration system will be kept in normal operation for 60 minutes before the next round of operation.

[0104] Other parts not described belong to the prior art.

Claims

1. A method for resource utilization of coal gas desulfurization solid waste, which couples the coal gas desulfurization solid waste disposal process with the waste acid regeneration process, and includes the following steps: 1) Using part of the waste acid liquid as a soaking agent, the coal gas desulfurization solid waste and the waste acid liquid are mixed and soaked in a closed state; the coal gas desulfurization solid waste is a by-product of the coke oven gas activated iron oxide dry desulfurization process; the waste acid liquid is the waste acid liquid generated by the pickling of strip steel in the cold-rolled thin plate production line; 2) introducing the gas generated after the soaking treatment together with the coal gas used as fuel into the roasting furnace of the waste acid regeneration system for combustion treatment; 3) sending the liquid generated after the soaking treatment together with the part of the waste acid liquid that is not used as the soaking agent into the pre-concentrator of the waste acid regeneration system, and processing through the roasting furnace, double cyclone dust collector and absorption tower of the waste acid regeneration system to recover the iron oxide powder and the regenerated acid; 4) Regularly clean and remove the solids generated after the soaking treatment.

2. The method for resource utilization of coal gas desulfurization solid waste according to claim 1, characterized in that: In the step 1), the chemical composition of the coal gas desulfurization solid waste includes: the mass percentage of TFe is 60-70%, and the mass percentage of S is 15-25%; the physical properties of the coal gas desulfurization solid waste are: the mass of particles with a particle size of less than 5 cm is ≥95%, and the mass of particles with a particle size of less than 2.36 cm is ≥60%.

3. The method for resource utilization of coal gas desulfurization solid waste according to claim 1, characterized in that: In the step 1), the waste acid solution contains HCl, and H + The ion concentration is 4-6 mol / L.

4. The method for resource utilization of coal gas desulfurization solid waste according to claim 1, characterized in that: In the step 1), before the soaking treatment, the step further includes: grinding the coal gas desulfurization solid waste, sieving it through a 30-mesh sieve, taking the material under the sieve for the soaking treatment, and re-grinding the material on the sieve; in the soaking treatment, the soaking temperature is 40-50° C., and the soaking time is 60-120 min.

5. The method for resource utilization of coal gas desulfurization solid waste according to claim 1, characterized in that: In the step 1), the mass ratio of the coal gas desulfurization solid waste to the waste acid liquid used for the soaking treatment is 1:6-10.

6. The method for resource utilization of coal gas desulfurization solid waste according to claim 1, characterized in that: In the step 1), the coal gas is one or a mixture of blast furnace gas, converter gas, coke oven gas.

7. The method for resource utilization of coal gas desulfurization solid waste according to claim 6, characterized in that: In the step 2), the gas generated after the soaking treatment is introduced into the roasting furnace through a fan and burned together with the coal gas, wherein the air supply volume of the fan is 2-5% of the volume of the coal gas, and the temperature of the roasting furnace is increased from the conventional 550-650°C to 800-850°C. After the combustion treatment is completed, the temperature of the roasting furnace is reduced to the conventional 550-650°C.

8. The method for resource utilization of coal gas desulfurization solid waste according to claim 1, characterized in that: In the step 3), in the mixed liquid sent to the waste acid regeneration system, the volume percentage of the liquid produced after the soaking treatment is 5-30%, and the volume percentage of the part of the waste acid liquid not used as the soaking agent is 70-95%.

9. The method for resource utilization of coal gas desulfurization solid waste according to any one of claims 1 to 8, characterized in that: In the step 3), the regenerated acid obtained contains HCl and H2SO4, and the sulfate in the H2SO4 is discharged through the spent acid desiliconization system in the spent acid regeneration system; in the step 4), the solids generated after the soaking treatment are cleaned regularly and the elemental sulfur is recovered by the vacuum potassium carbonate method.

10. A resource utilization device for solid waste from coal gas desulfurization, comprising a waste acid regeneration system for recovering waste acid liquid generated by a strip cold rolling pickling unit, wherein the waste acid regeneration system mainly consists of a waste acid tank, a pre-concentrator, a roasting furnace, a double cyclone dust collector, an absorption tower, a regenerated acid tank, an iron oxide powder collection system, a flue gas purification system, and a waste acid desiliconization system; characterized in that: It also includes a disposal tank for sealed immersion treatment of coal gas desulfurization solid waste and waste acid liquid, and the disposal tank is respectively provided with a desulfurization solid waste inlet, a waste acid inlet, a gas outlet and a liquid outlet, the desulfurization solid waste inlet is connected to the discharge end of the desulfurization solid waste grinding system, the waste acid inlet is connected to the first output end of the waste acid tank, the gas outlet is connected to the burner inlet of the roasting furnace, and the liquid outlet is connected to the mixed liquid inlet of the pre-concentrator.

Images