A method for harmlessly treating hazardous waste desulfurizer using Ouye furnace

Abstract

The invention discloses a method for harmlessly treating hazardous waste desulfurizer by using an Ouye furnace. The method reduces sulfur in the hazardous waste desulfurizer into elemental sulfur by using the reducing atmosphere of the Ouye furnace system. The sulfur is fixed and slaged through a chemical reaction in the furnace. The slag is economically treated as a building material. The production process of the invention is stable, and the treatment volume of the waste desulfurizer is large. The discharge of secondary pollutants is eliminated, and the method has obvious environmental benefits. The coordinated treatment of the waste desulfurizer by the Ouye furnace breaks through the process limit of the traditional coordinated treatment of solid waste / hazardous waste by using a cement rotary kiln, and achieves the goal of large-scale coordinated treatment of the waste desulfurizer in the metallurgical furnace - the Ouye furnace, develops a new way to treat solid waste / hazardous waste, and achieves low cost, harmless treatment in a reducing atmosphere without generating secondary pollution of dioxins, large treatment capacity, and high-value treatment of solid waste / hazardous waste, filling the gaps at home and abroad.

Description

Technical Field

[0001] The invention relates to the technical field of environmental protection for harmless treatment of hazardous waste, in particular to a method for harmlessly treating hazardous waste desulfurizing agent with an Ouye furnace. Background Art

[0002] At present, the comprehensive utilization, disposal and storage volumes of general industrial solid waste account for 42.5%, 17.1% and 40.3% respectively; the comprehensive utilization, disposal and storage volumes of industrial hazardous waste account for 48.6%, 40.7% and 10.7% respectively; at the same time, the comprehensive utilization rates of general industrial solid waste and hazardous waste are both lower than 50%.

[0003] Based on the above practical problems, domestic and foreign scholars have studied the technology of using cement kilns to co-treat urban solid waste / hazardous waste. Such co-treatment can achieve low investment and low cost treatment of solid waste / hazardous waste. This technology has been extensively studied and practiced in my country, and has formed relevant national standards such as "Design Specifications for Co-treatment of Garbage in Cement Kilns" (GB50954-2014), "Design Specifications for Co-treatment of Sludge in Cement Kilns" (GB50757-2012), "Design Specifications for Co-treatment of Industrial Waste in Cement Kilns" (GB50634-2010), and "Pollution Control Standards for Co-treatment of Solid Waste in Cement Kilns" (GB30485-2013). However, due to the low treatment temperature of the rotary kiln, which generally does not exceed 1450℃, and the short residence time; it is easy to form secondary pollutants and oxidative atmosphere, that is, to produce more kiln dust and flue gas, of which kiln dust is classified as hazardous waste, and flue gas contains pollutants such as dioxins, SO2, and NOx.

[0004] Based on the characteristics of Ouyelu's metallurgical furnaces, in order to solve the existing problems of difficult solid waste / hazardous waste treatment, secondary pollution in the treatment process, and high treatment costs, new process tests are carried out to treat waste desulfurizers using metallurgical furnaces represented by Ouyelu. Summary of the invention

[0005] In order to overcome the deficiencies in the prior art, the present invention provides a method for harmlessly treating hazardous waste desulfurizers using an Ouye furnace, develops a new process for treating waste desulfurizers using metallurgical furnaces represented by the Ouye furnace, and enables the Ouye furnace system to smoothly dispose of waste desulfurizers.

[0006] To achieve the above-mentioned purpose, the present invention provides a method for harmlessly treating hazardous waste desulfurizers with an Ouye furnace, which utilizes the reducing atmosphere of the Ouye furnace system to reduce sulfur in hazardous waste to elemental sulfur, and after a chemical reaction in the furnace, metallic iron reacts with sulfur in the reduction shaft furnace to form FeS, and desulfurizes in a gasifier to form CaS, thereby achieving fixed slag of sulfur, and the slag is economically treated as a building material, and specifically comprises the following steps;

[0007] Step I, weighing and batching: the program automatically controls the process of screening the fuel, and the waste desulfurizer is weighed synchronously according to the weighing amount set by the batching weighing system according to the batching ratio;

[0008] The screening of fuel and the weighing of hazardous waste desulfurizer are achieved by adding independent screening and weighing equipment to each silo under the tank group. The hazardous waste desulfurizer uses the middle tank of the tank group, and a weighing hopper is set under the tank.

[0009] Step II, mixing the materials, evenly spreading the weighed desulfurizer on the middle layer of the materials, forming a natural layer on the conveyor belt, and completely mixing them during the transportation process through two intermediate transfer bins, and storing them in the coal loading bunker;

[0010] Step III, slag desulfurization: The mixed fuel in the coal bunker is fed into the gasifier. Under the high temperature of the molten pool in the gasifier, 80-85% of the carbon in the waste desulfurizer is burned: 2C+O 2 =2CO ignites to release heat and forms reducing gas;

[0011] In the reducing atmosphere of the gasifier, the sulfur compounds in the hazardous waste desulfurizer react with the alkaline substances in the charge in the smelting zone of the gasifier to form stable sulfides that are only soluble in slag. The reducing coal gas in the gasification zone at the top of the gasifier enters the reducing shaft furnace through the surrounding pipe. The sulfur compounds in the reducing coal gas react with the metal Fe in the shaft furnace to form FeS. FeS enters the melting gasifier through the DRI downcomer and is desulfurized in the slag of the gasifier. The reaction is as follows:

[0012] FeS+GaO=GaS+Fe+ ½O 2 -4.18×1995KJ / Kg endothermic reaction;

[0013] The gas in the gasification zone of the gasifier dome is a reducing atmosphere mainly composed of CO, and the specific components include: 9.29% CO 2 , 70.96%CO, 14.57%H 2 、1.07%N 2 4.11% H 2 O.

[0014] Furthermore, a two-furnace three-stage process is adopted to achieve efficient gasification of dry pulverized coal at the dome of the gasifier by spraying dry pulverized coal and burner oxygen at the dome of the gasifier;

[0015] Furthermore, cold gas is added to the bottom of the reduction shaft furnace to suppress the backflow of gas and the central gas flow of the shaft furnace distribution, wherein the cold gas accounts for 20% of the total gas entering the reduction shaft furnace, and the remaining 80% is the surrounding pipe reduction gas.

[0016] Furthermore, the reducing coal gas from the gasifier dome first enters the cold cyclone dust collector through the gas generating pipeline for dust removal, and then part of the reducing coal gas enters the reducing vertical furnace through the surrounding pipe to react with the furnace charge and is mixed with the top coal gas for output, and the other part of the reducing coal gas is directly output after being washed by the washing tower, wherein the dust collected in the cold cyclone dust collector is sprayed into the gasifier dome together with oxygen.

[0017] Furthermore, the top gas is circulated: the top gas is passed through the bag filter to the output gas, the output gas is pressurized by the compressor, and enters the deCO 2 The system captures carbon and removes CO 2 The reducing coal gas is heated by the heat exchange furnace and then sent back to the composite oxygen injection tuyere of the gasifier for injection.

[0018] Furthermore, the charge is distributed through the vertical furnace distributor, achieving full coverage of the charge surface with a radius of 3.5m.

[0019] Furthermore, the vertical furnace distributor is arranged at the top center of the reduction vertical furnace, and the vertical furnace distributor includes a hopper and a distribution trough rotatably arranged relative to the lower port of the hopper, the lower port of the hopper vertically extends to the interior of the reduction vertical furnace, the lower port of the hopper is provided with a rotating frame, the distribution trough is hingedly arranged on the rotating frame, the lower port of the hopper is aligned with the notch of the feeding end of the distribution trough, and the distribution port is provided at the swinging end of the distribution trough.

[0020] Furthermore, both sides of the bottom of the reduction vertical furnace are connected to the gasifier arch through the DRI downcomers, the gasifier arch is connected to the cold cyclone dust collector through the gas generation pipeline, the top air outlet of the cold cyclone dust collector is connected to the middle of the reduction vertical furnace through the surrounding pipe, the surrounding pipe is arranged around the outer wall of the middle of the reduction vertical furnace, and the bottom dust outlet of the cold cyclone dust collector is connected to the gasifier arch.

[0021] Furthermore, the composite oxygen injection tuyere is arranged on the furnace wall of the smelting zone of the gasifier, and the composite oxygen injection tuyere includes an oxygen channel and a coal gas channel, and a cooling cavity is arranged around the outer sides of the oxygen channel and the coal gas channel.

[0022] Furthermore, the coal loading bunker is connected to the center of the gasifier dome.

[0023] Beneficial effects: The method of harmlessly treating hazardous waste desulfurizers by using an Ouye furnace of the present invention has a stable production process and a large waste desulfurizer treatment capacity; it eliminates secondary pollutant emissions and has obvious environmental benefits; the coordinated treatment of waste desulfurizers by using an Ouye furnace breaks through the process limits of the traditional use of cement rotary kilns to coordinately treat solid waste / hazardous wastes, and achieves the goal of large-scale coordinated treatment of waste desulfurizers in the metallurgical furnace - the Ouye furnace, develops a new approach to solid waste / hazardous waste treatment, and achieves low cost, harmless reduction of the atmosphere without generating secondary pollution of dioxins, large treatment capacity, and high-value treatment of solid waste / hazardous waste, filling domestic and foreign gaps. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Attached Figure 1 A block diagram of a method for harmlessly treating hazardous waste desulfurizer by using an Ouye furnace according to the invention;

[0025] Attached Figure 2 This is a table comparing the practical data on the requirements for the waste desulfurizer ton iron ratio on the molten iron quality and slag basicity;

[0026] Attached Figure 3 This is the process flow chart of the low-carbon cycle of Ouye furnace;

[0027] Attached Figure 4 This is the reaction state diagram of the two-furnace three-stage process gasifier;

[0028] Attached Figure 5 This is the structural diagram of the Ouye furnace system;

[0029] Attached Figure 6 This is the structural diagram of the vertical furnace distributor;

[0030] Attached Figure 7 This is a structural diagram of the composite oxygen injection tuyere. DETAILED DESCRIPTION

[0031] The present invention will be further described below in conjunction with the accompanying drawings.

[0032] As attached Figure 1 The method of harmlessly treating hazardous waste desulfurizer by using an Ouye furnace utilizes the reducing atmosphere of the Ouye furnace system to reduce the sulfur in the hazardous waste into elemental sulfur. After a chemical reaction in the furnace, metallic iron reacts with sulfur in the reduction shaft furnace 1 to form FeS, and desulfurizes in the gasification furnace 2 to form CaS, thereby achieving fixed slag of sulfur. The slag is economically treated as a building material. Specifically, the following steps are included:

[0033] Step I, weighing and batching: the program automatically controls the process of screening the fuel, and the waste desulfurizer is weighed synchronously according to the weighing amount set by the batching weighing system according to the batching ratio;

[0034] Among them, the screening of fuel and the weighing of hazardous waste desulfurizer are achieved by adding independent screening and weighing equipment to each silo under the tank group;

[0035] Step II, mixing materials, evenly laying the weighed desulfurizer on the middle layer of materials, forming natural stratification on the conveyor belt, and completely mixing during the transportation process through two intermediate transfer bins, and storing in the coal bunker 12; Among them, the hazardous waste desulfurizer uses the middle tank of the storage tank group, and a weighing hopper is set under the tank, so as to achieve even laying of the desulfurizer on the middle layer of materials

[0036] Step III, slag desulfurization: The mixed fuel in the coal bunker 12 is fed into the gasifier 2. Under the high temperature of the molten pool in the gasifier 2, 80-85% of the carbon in the waste desulfurizer is burned: 2C+O 2 =2CO (a) ignites and releases heat to form reducing gas;

[0037] In the reducing atmosphere of the gasifier 2, the sulfur compounds in the hazardous waste desulfurizer react with the alkaline substances in the charge in the smelting zone of the gasifier 2 to form stable sulfides that are only soluble in slag. The reducing coal gas in the gasification zone at the top of the gasifier 2 enters the reducing shaft furnace 1 through the surrounding pipe 3. The sulfur compounds in the reducing coal gas react with the metal Fe in the shaft furnace to form FeS. The reaction equation is: Fe+½S 2 =FeS (b), heating under certain conditions, the metal Fe in the vertical furnace is in excess, and the vertical furnace charge bed is used as a filter layer to achieve desulfurization of sulfides in coal gas. FeS enters the melter gasifier 2 through the DRI downcomer 7. Desulfurization is carried out in the gasifier slag.

[0038] The reaction is as follows, FeS+GaO=GaS+Fe+ ½O 2 (c) -4.18×1995KJ / Kg endothermic reaction;

[0039] The gas in the gasification zone of the gasifier dome is a reducing atmosphere mainly composed of CO, and the specific components include: 9.29% CO 2 , 70.96%CO, 14.57%H 2 、1.07%N 2 4.11% H 2 O.

[0040] The amount of waste desulfurizer used is calculated according to the desulfurization capacity of the slag in the furnace. The target sulfur content of molten iron is less than 0.075% to meet the qualified standard. The total amount of sulfur in the raw fuel consumed by a ton of iron is called sulfur load. According to the theoretical calculation of desulfurization in the ironmaking process and the theoretical calculation of slag desulfurization capacity, adding 15kg of desulfurizer to a ton of iron will not affect the quality of molten iron. The desulfurization capacity of the slag can meet production needs and no more investment is required. Figure 2As shown, the results of theoretical calculations are verified by comparing multiple sets of production practice record data. It can be seen from the charts that the practical results are in line with the theoretical calculations. Therefore, the optimal usage amount of waste desulfurizer per ton of iron is 15 kg.

[0041] Based on the above method, analyze the behavior of sulfur in the furnace:

[0042] As the burden descends and the temperature rises in the furnace, part of the sulfur in the burden volatilizes into the gas. About 30% - 50% of the organic sulfur in the coke volatilizes first in the form of compounds such as CS and COS from the lower part of the shaft to the bosh, and the rest forms SO 2 , H 2 S and other gaseous compounds enter the gas. Part of the sulfur in the ore and flux also decomposes or reacts to form sulfur vapor or SO 2 and enters the gas. The sulfur entering the gas phase is absorbed by the descending burden in the reduction shaft furnace. In the lump zone, the ore absorbs less sulfur at 200 - 900 °C and the absorption accelerates at about 1000 °C. In the gasifier, the sulfur absorption condition of the burden is good, the sulfur content increases, and the slag and iron vigorously absorb the sulfur in the gas. At the same time, sulfur transfers from iron to slag.

[0043] In the hearth, the iron droplets pass through the slag layer with good reaction conditions, and a large amount of desulfurization reactions occur. At the interface of the slag and iron accumulated in the hearth, the desulfurization reaction continues until tapping, and the desulfurization of iron still occurs between the lower slag and the molten iron in the iron notch channel. The desulfurization reaction of the slag: Sulfur exists in the molten slag in various sulfide forms. The several main sulfides are arranged in ascending order of stability as FeS, MnS, MgS, CaS, and FeS can also dissolve in the molten iron. The desulfurization reaction of the slag is that the basic oxides such as CaO and MgO in the slag react with the sulfur in the molten iron to form stable compounds such as CaS and MgS that are insoluble in the molten iron but soluble in the slag, so that the sulfur in the molten iron transfers to the slag and is removed. In a reducing atmosphere, the sulfur in the hot coke and the C dissolved in the molten iron undergo a desulfurization reaction:

[0044] (CaO)+[S]+[C] - (CaS)+CO(d)

[0045] Equation (d) can explain the reaction mechanism by the molecular theory, that is, FeS in the molten iron diffuses through the slag-iron interface into the molten slag, reacts with CaO in the molten slag to form CaS and FeO, and the generated FeO is reduced by C to Fe, and the generated CO leaves the reaction interface and enters the gas. Using the ionic theory to explain the reaction mechanism, an ion migration process occurs at the liquid slag-iron interface. The neutral atomic sulfur in the molten iron absorbs electrons from the molten slag at the slag-iron interface and becomes a sulfur anion S 2 — and enters the molten slag, while the oxygen anion O 2—It loses electrons at the interface and becomes a neutral atom, enters the molten iron and combines with C in the molten iron to form CO, which is discharged from the molten iron.

[0046] Since there are other elements such as Si and Mn in the molten iron, these elements also interact with the S in the molten iron to desulfurize in the form of coupled reactions:

[0047] 2[S]+ [Si] +2(CaC))-2(CaS)+(SiO 2 )(e)

[0048] [S]+[Mn]+(CaO)-(CaS)+(MnO)(f)

[0049] Or it can be written as 2[S]+[Si]+2O 2 —2S 2 —+(SiO 2 )(g)

[0050] [S]+[Mn]+O 2 ——S 2 —+(MnO)(h)

[0051] The distribution coefficient of sulfur between slag and molten iron: When the desulfurization reaction (d) in the Ouye furnace reaches equilibrium, the ratio of the mass percentage concentration of sulfur between slag and molten iron is called the distribution coefficient of sulfur between slag and iron. Under the condition of 1500℃ furnace temperature in the melting gasification furnace, the slag basicity is about 1.0. When the reaction reaches equilibrium, Ls can reach more than 200. However, in actual production, due to the limitations of conditions, the desulfurization reaction cannot reach equilibrium, and the Ls value can only reach 20-50, and the highest does not exceed 80. Therefore, efforts should be made to improve the thermodynamic and kinetic conditions of desulfurization in ironmaking to increase the Ls value and reduce the S in the molten iron.

[0052] In daily production, the theoretical sulfur load is generally about 5-8 kg / ton of iron. The sulfur content in the waste desulfurizer is about 12%, and the carbon content is about 85%. If 15 kg is added to a ton of iron, the sulfur load will increase by about 1.8 kg / ton of iron, and the carbon content will increase by 12.75 kg / ton of iron. The furnace molten pool temperature of Ouye furnace is 2000℃, and the carbon of the added desulfurizer meets the thermal balance condition. There is no additional consumption. Increasing the amount of desulfurizer will break the thermal balance and increase the production fuel input, which loses economic significance.

[0053] Theory guides the actual production process. In the test of production process, adding 15kg desulfurizer to one ton of iron does not affect the quality of molten iron and slag, which confirms the correctness of the theory. Ouye furnace has successfully achieved harmless treatment of waste desulfurizer.

[0054] A two-furnace three-stage process is adopted: by spraying dry coal powder and burner oxygen on the dome of the gasifier 2, efficient gasification of the dry coal powder on the dome of the gasifier is achieved. As a preferred embodiment, multiple nozzles of dry coal powder and burner oxygen can be evenly distributed around the furnace wall of the gasifier, and the burner oxygen nozzle is relatively arranged below the dry coal powder nozzle, wherein the burner oxygen nozzle can be inclined downward at an angle of 8° to the horizontal direction.

[0055] like Figure 4 As shown, from top to bottom in the internal space of the gasifier, the reactions are:

[0056] CO + ½ O 2 =CO 2 (i)

[0057] C+CO 2 =2CO(j)

[0058] C+H 2 O=CO+H 2 (k).

[0059] Through the study of the multi-directional turbulent reaction flow process of the gasification furnace gas flow section, the carbonization time of 0.074mm coal powder in the gasification furnace arch is only 1.5s, and the carbon conversion rate is more than 96.5%. It is calculated that it takes 32s for the particle discharge surface to enter the riser and escape. When the gasification of dry coal powder in the arch reaches 200kg / t.hm, the gas composition is effectively adjusted, and the metal conversion rate of the vertical furnace is increased by 15%~25%. This technology can increase the proportion of thermal coal in the fuel to 20%-60%, thereby reducing costs.

[0060] Cold gas is added at the bottom of the reduction shaft furnace 1 to suppress backflow of gas and central airflow in the shaft furnace distribution; wherein, the cold gas accounts for 20% of the total gas volume entering the reduction shaft furnace 1, and the remaining 80% is the reduction gas entering through the enclosure pipe. Since the high-temperature gas of the gasifier passes through the DRI downcomer and high-temperature liquid phase adhesion occurs, and the shaft furnace enclosure pipe chokes the material, it will cause a high pressure difference, which intensifies the backflow of the high-temperature gas, forming a vicious circle, causing the lower furnace charge to melt and become bonded. By cooling the gas at the bottom of the shaft furnace, the temperature is reduced to below the ore softening temperature range, thereby suppressing the backflow of the high-temperature gas flow, softening and bonding.

[0061] like Figure 3 As shown, the reducing coal gas from the dome of the gasifier 2 first enters the cold cyclone dust collector 6 through the gas generating pipeline 5 for dust removal, and then part of the reducing coal gas enters the reducing vertical furnace 1 through the surrounding pipe 3 to react with the furnace charge in the furnace and is mixed with the top coal gas for output, and the other part of the reducing coal gas is directly output after being washed by the washing tower, wherein the dust collected in the cold cyclone dust collector 6 is sprayed into the dome of the gasifier 2 together with oxygen, which can replace the effect of spraying part of the dry coal powder and achieve the effect of harmless treatment of solid waste.

[0062] Top gas circulation: Top gas is passed into output gas through bag dust removal, and the output gas is pressurized by a compressor and enters the deCO 2 The system captures carbon and removes CO 2 The reducing coal gas is heated by the heat exchange furnace and then returned to the composite oxygen injection tuyere 4 of the gasifier for injection; all-round resource coupling is achieved, and the hydrogen-rich carbon circulation blast furnace tuyere injects 12000Nm³ / h, reducing the fuel ratio by 10%. After cooling, it can also replace part of the cold coal gas and be input into the bottom of the reduction shaft furnace.

[0063] The charge is distributed through the vertical furnace distributor 8, achieving full coverage of the charge surface with a radius of 3.5m. This improves the utilization rate of the vertical furnace gas from 29.8% before commissioning to 36.3% after commissioning, and has a long service life.

[0064] like Figure 5-6 As shown, the vertical furnace distributor 8 is arranged at the top center of the reduction vertical furnace 1, and the vertical furnace distributor 8 includes a hopper 9 and a distribution trough 10 rotatably arranged relative to the lower end of the hopper 9, the lower end of the hopper 9 vertically extends to the interior of the reduction vertical furnace 1, and the lower end of the hopper 9 is provided with a rotating frame 11, and the distribution trough 10 is hingedly arranged on the rotating frame 11, the lower end of the hopper 9 is aligned with the notch 10-1 of the feeding end of the distribution trough 10, and the swing end of the distribution trough 10 is provided with a distribution port 10-2.

[0065] When adding charge from the hopper to the reduction vertical furnace, the control system controls the rotating frame to rotate at a uniform speed, and the distribution trough intermittently and regularly adjusts the swing angle to form distribution circles of different radii, with the maximum distribution radius reaching 3.5m, thereby achieving full coverage of the material surface with a circumferential radius of 3.5m. This not only realizes large-area spiral layer-by-layer distribution, but also ensures the uniformity of the distribution, so that the sulfur entering the gas phase is fully and evenly mixed with the descending charge in the reduction vertical furnace, so that the charge can better absorb the sulfur entering the gas phase, and then more sulfur can enter the gasifier to achieve sulfur slag fixation, so as to obtain a better desulfurization effect.

[0066] The two sides of the bottom of the reduction shaft furnace 1 are connected to the dome of the gasifier 2 through the DRI downcomer 7, and the dome of the gasifier 2 is connected to the cold cyclone dust collector 6 through the gas generation pipeline 5. The top gas outlet of the cold cyclone dust collector 6 is connected to the middle of the reduction shaft furnace 1 through the surrounding pipe 3. The surrounding pipe 3 is arranged around the outer wall of the middle part of the reduction shaft furnace 1, and the bottom dust outlet of the cold cyclone dust collector 6 is connected to the dome of the gasifier 2;

[0067] Among them, multiple cold cyclone dust collectors can be provided, as a preferred embodiment, such as Figure 5As shown in , four cold cyclone dust collectors are arranged evenly around the gasifier dome and connected to the gasifier through a separate gas generation pipeline, so that the gas pressure at each position of the gasifier dome can be stabilized and balanced, and the efficiency of the reduction gas circulation is also improved;

[0068] The reducing gas from the gasifier vault enters the cold cyclone dust collector through the gas generating pipeline, separates and collects the solid particles entrained in the gas, and can be used to replace the dry coal powder in the above-mentioned two-furnace three-stage process for injection back into the furnace, achieving the effect of solid waste recycling. It can not only realize the repeated full utilization of fuel charge, but also can return the solid sulfur brought out with the solid particles to the furnace for desulfurization. The gas enters the reduction vertical furnace through the surrounding pipe. The surrounding pipe is evenly provided with a number of air inlets corresponding to the furnace wall of the reduction vertical furnace, so that the gas can be evenly distributed in the reduction vertical furnace, and cooperate with the above-mentioned vertical furnace distributor to further mix the gas phase sulfur with the charge, so as to obtain a better desulfurization effect.

[0069] The coal bunker 12 is connected to the center of the dome of the gasifier 2, and the mixed fuel is dropped from the center of the dome of the gasifier 2 to form a Figure 4 As shown in the figure, when the charge is continuously laid on the conical charge surface through the DRI downcomers on both sides, the mixed fuel is continuously added from the top center, and when the charge falls to the top of the conical charge surface, it spreads evenly around to maintain the shape of the conical charge surface. In this process, the fuel evenly diffused around is mixed with the continuously falling charge, and the oxygen injection ports evenly arranged around the furnace wall can realize uniform and stable combustion of the charge in the furnace, so that the desulfurization reaction occurs stably in all areas of the furnace, and a better desulfurization effect is obtained.

[0070] The composite oxygen injection tuyere 4 is arranged on the furnace wall of the smelting zone of the gasifier 2, and the composite oxygen injection tuyere 4 includes an oxygen channel 4-1 and a coal gas channel 4-2. A cooling cavity 4-3 is arranged around the outer sides of the oxygen channel 4-1 and the coal gas channel 4-2. By adopting the injection oxygen tuyere of this structure, the coal gas channel can be connected to the deCO 2 The reducing gas can realize the recycling of top gas. The gas return to the furnace can effectively reduce the fuel ratio. At the same time, it can also be used as a means to reduce silicon in molten iron, which not only reduces costs but also improves the quality of iron.

[0071] Based on the above basic structural relationship, four types of gas injection tuyere sets can be developed, including single-cavity single-channel type, single-cavity double-channel type, double-cavity single-channel type, and double-cavity double-channel type. Figure 7As shown, the oxygen channel and the coal gas channel can be arranged separately (double channel) or connected (single channel). When connected, the coal gas channel outlet can be set in the middle of the oxygen channel so that the oxygen is mixed with the coal gas before being ejected; based on the above two connection methods, both can correspond to two cooling chamber layout methods, the first one adopts a complete through cavity (single cavity), and the through cavity is cooled by cooling liquid, and the second one divides the cooling cavity into a front cooling cavity 4-31 and a rear cooling cavity 4-32 (double cavity), and the front cooling cavity 4-32 is set at the outlet; the two channel layout methods and the two cooling cavity layout methods are combined in pairs to form four types of air outlets, among which, in the double cavity single channel type, the connection between the oxygen channel and the coal gas channel is set in the rear cooling cavity 4-32;

[0072] In the application of composite oxygen injection tuyere, different options can be made according to the combustion requirements in the furnace and the influence of the temperature in the furnace on the tuyere. For tuyere that does not need to be cooled in sections, a single-chamber structure is used, and the oxygen pipeline and the gas pipeline are cooled and cooled by passing coolant in the chamber at the same time; for tuyere that needs to be cooled in sections, usually because the tuyere is close to the combustion point, its temperature is higher, and the required cooling requirement is higher, and the cooling requirement is lower the further out, in order to reduce the loss of cooling energy, a double-chamber structure is used, and conventional temperature coolant is passed into the rear cooling chamber, and lower temperature coolant is passed into the front cooling chamber, so as to obtain better cooling effect, and the two cooling chambers are independent of each other, and each cooling chamber is connected to an independent cooling cycle. At the same time, the barrier between the two chambers can be made of materials with good thermal insulation performance to reduce the heat transfer between the two chambers and avoid affecting the effect of section cooling;

[0073] As for the choice of single or double channels, it is not necessary to choose one of them. You can also combine them according to the advantages of the two. Among them, the single channel adopts the method of mixing first and then blowing. The sprayed mixed gas ignites to form a jet-shaped columnar flame, which heats and ignites the fuel at the injection point in a targeted manner; while the double channel uses oxygen and gas to spray separately, such as Figure 7 As shown, the gas pipeline nozzle is slightly inclined toward the oxygen pipeline nozzle, so that after the two gases are ejected in a high-speed airflow, they collide with each other and disperse in the furnace, and form a sputtering type range flame after ignition, which can provide a large range of stable and continuous heat supply, so that the fuel can be fully burned; according to the advantages of both, two types of blowing air outlets, single-channel and double-channel, can be selected to be alternately arranged, which has formed a rapid ignition method for multiple points and rapid spread of flames at each point to connect into a piece, and subsequently provide a continuous and stable flame, thereby providing a good reaction environment for the desulfurization reaction in the furnace and improving efficiency.

[0074] The above description is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the above principles of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A method for harmlessly treating hazardous waste desulfurizer by using an Ouye furnace, characterized in that: The sulfur in the hazardous waste desulfurizer is reduced to elemental sulfur by using the reducing atmosphere of the Ouye furnace system. After the chemical reaction in the furnace, the sulfur is fixed and slag is formed. The slag is used as a building material for economical treatment. Specifically, the following steps are included: Step I, weighing and batching: the program automatically controls the process of screening the fuel, and the waste desulfurizer is weighed synchronously according to the weighing amount set by the batching weighing system according to the batching ratio; Step II, mixing the materials, evenly spreading the weighed desulfurizer on the middle layer of the fuel, forming a natural layer on the conveyor belt, passing through two intermediate transfer bins to completely mix during the transportation process, and storing in the coal loading bin (12); Step III, slag desulfurization: the mixed fuel in the coal bunker (12) is fed into the gasifier (2), and the carbon in the waste desulfurizer is burned to form reducing coal gas under the high temperature of the molten pool in the gasifier (2); the reducing coal gas in the gasification zone at the top of the gasifier (2) enters the reducing shaft furnace (1) through the surrounding pipe (3), and the sulfur compound in the reducing coal gas reacts with the metal Fe in the shaft furnace to form FeS, and the mixed fuel doped with FeS enters the gasifier (2) as a furnace charge through the DRI downcomer (7); In the reducing atmosphere of the gasifier (2), part of the sulfur in the charge evaporates and enters the coal gas as the charge descends and the temperature rises. 30% to 50% of the organic sulfur in the coke in the fuel first evaporates in the form of CS and COS compounds from the lower part of the furnace body to the belly. The rest of the sulfur, SO2, H2S and other gaseous compounds generated during the gasification reaction and combustion in front of the combined oxygen injection tuyere (4) of the gasifier, enter the coal gas. Part of the sulfur in the ore and sulfur-containing flux in the fuel also decomposes or reacts to generate sulfur vapor or SO2 and enters the coal gas. The sulfur that enters the gas phase is absorbed by the descending charge in the reducing shaft furnace. In the massive zone, the ore in the fuel absorbs sulfur faster at about 1000°C, and the sulfur content increases the intensity of the slag and iron absorbing sulfur in the coal gas, and at the same time, sulfur transfers from iron to slag; At the interface between liquid slag and iron, the iron droplets pass through the slag layer with favorable reaction conditions, undergoing the ion migration process. The neutral atomic sulfur in the molten iron absorbs electrons in the slag at the slag-iron interface and becomes sulfur anions S. 2- Enter the slag, and the oxygen negative ions O in the slag 2- It loses electrons at the interface and becomes a neutral atom, entering the molten iron and combining with C in the molten iron to form CO. This process causes the alkaline oxides in the slag to react with the sulfur in the molten iron to form a stable compound that is insoluble in the molten iron but soluble in the slag, causing the sulfur in the hot coke and the C dissolved in the molten iron to undergo a desulfurization reaction: (CaO)+[S]+[C]→(CaS)+CO. The FeS in the molten iron diffuses into the slag through the slag-iron interface and reacts with the CaO in the slag to form CaS and FeO. The FeO generated by the reaction is then reduced to Fe by C, and the generated CO leaves the reaction interface and enters the coal gas. In molten iron, there are Si and Mn elements, which interact with S in the molten iron to desulfurize in the form of coupled reaction, achieving the fixed slag of sulfur.

2. The method for harmlessly treating hazardous waste desulfurizer by using an Ouye furnace according to claim 1 is characterized in that: A two-furnace three-stage process is adopted, and dry pulverized coal and burner oxygen are sprayed on the dome of the gasifier (2), thereby achieving efficient gasification of the dry pulverized coal on the dome of the gasifier (2).

3. The method for harmlessly treating hazardous waste desulfurizer by using an Ouye furnace according to claim 2 is characterized in that: By adding cold coal gas at the bottom of the reduction shaft furnace (1), backflow of coal gas and the central air flow of the shaft furnace can be suppressed.

4. The method for harmlessly treating hazardous waste desulfurizer by using an Ouye furnace according to claim 3 is characterized in that: The reducing coal gas from the dome of the gasifier (2) first enters the cold cyclone dust collector (6) through the gas generating pipeline (5) for dust removal, and then part of the reducing coal gas enters the reducing vertical furnace (1) through the surrounding pipe (3) to react with the furnace charge in the furnace and then is mixed with the top coal gas for output, while the other part of the reducing coal gas is washed in the washing tower and then directly output, wherein the dust collected in the cold cyclone dust collector (6) is sprayed into the dome of the gasifier (2) together with oxygen.

5. The method for harmlessly treating hazardous waste desulfurizer by using an Ouye furnace according to claim 4 is characterized in that: Top gas circulation: The top gas is introduced into the output gas through the bag dust collector, the output gas is pressurized by the compressor, and enters the CO2 removal system for carbon capture. The reduced gas without CO2 is heated by the heat exchange furnace and then returned to the composite oxygen injection tuyere (4) of the gasifier for injection.

6. The method for harmlessly treating hazardous waste desulfurizer by using an Ouye furnace according to claim 1 is characterized in that: The charge is distributed through the vertical furnace distributor (8), so that the charge surface is fully covered with a radius of 3.5 m.

7. The Ouye furnace system in the method for harmlessly treating hazardous waste desulfurizer by Ouye furnace according to any one of claims 1 to 6 is characterized in that: A shaft furnace distributor (8) is arranged at the top center of the reduction shaft furnace (1), and the shaft furnace distributor (8) comprises a hopper (9) and a distribution trough (10) rotatably arranged relative to a lower end of the hopper (9), the lower end of the hopper (9) vertically extending into the interior of the reduction shaft furnace (1), a rotating frame (11) is arranged at the lower end of the hopper (9), the distribution trough (10) is hingedly arranged on the rotating frame (11), the lower end of the hopper (9) is aligned with a notch (10-1) at the feeding end of the distribution trough (10), and a distribution port (10-2) is arranged at a swing end of the distribution trough (10).

8. The Ouye furnace system in the method for harmlessly treating hazardous waste desulfurizer by using an Ouye furnace according to claim 7 is characterized in that: The two sides of the bottom of the reduction shaft furnace (1) are connected to the dome of the gasifier (2) through DRI downcomers (7), the dome of the gasifier (2) is connected to a cold cyclone dust collector (6) through a gas generation pipeline (5), the top gas outlet of the cold cyclone dust collector (6) is connected to the middle of the reduction shaft furnace (1) through a surrounding pipe (3), the surrounding pipe (3) is arranged around the outer wall of the middle of the reduction shaft furnace (1), and the bottom dust outlet of the cold cyclone dust collector (6) is connected to the dome of the gasifier (2).

9. The Ouye furnace system in the method for harmlessly treating hazardous waste desulfurizer by using an Ouye furnace according to claim 8 is characterized in that: The composite oxygen injection tuyere (4) is arranged on the furnace wall of the smelting zone of the gasification furnace (2), and the composite oxygen injection tuyere (4) comprises an oxygen channel (4-1) and a coal gas channel (4-2), and a cooling cavity (4-3) is arranged around the outer sides of the oxygen channel (4-1) and the coal gas channel (4-2).

10. The Ouye furnace system in the method for harmlessly treating hazardous waste desulfurizer by using an Ouye furnace according to claim 9 is characterized in that: The coal loading bin (12) is connected to the center of the dome of the gasifier (2).

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