Device for purifying clear liquid after sulfur melting

Abstract

The utility model discloses a device for purifying clear liquid after sulfur melting. The device comprises an oxidation tower for receiving the clear liquid after sulfur melting, a clear liquid tank connected with the oxidation tower, a centrifugal machine connected with the clear liquid tank and a heat exchanger connected with the centrifugal machine. According to the device for purifying the clear liquid after sulfur melting disclosed by the utility model, the impurity content of the clear liquid can be effectively reduced by arranging the clear liquid tank connected with the oxidation tower, and the required equipment cost is relatively low, so that the cost can be reduced.

Description

Technical Field

[0001] The utility model belongs to the technical field of solid waste and liquid waste resource recovery and reuse. Specifically, the utility model relates to a device for purifying and treating the clarified liquid after sulfur melting. Background Technique

[0002] Coke is widely used in the production of blast furnace ironmaking, cupola iron melting, ferroalloy smelting, non-ferrous metal smelting, etc. During the smelting process, it serves as a reducing agent, energy source, and carbon supplier. It can also be used as a raw material in the fields of calcium carbide production, gasification, and synthetic chemistry. For cokes with different uses, there are specific requirements. However, since more than 90% of the coke production in many countries is used for blast furnace ironmaking, the quality of blast furnace coke is the most important, and the environmental problems it brings are also the most prominent.

[0003] Through the high-temperature carbonization process of coal, solid product coke and gaseous products collectively called raw coke oven gas can be obtained. Among them, in the process of raw coke oven gas, the raw coke oven gas enters the collecting pipe from the top space of the furnace through the riser pipe and the bridge pipe, is cooled by the sprayed circulating ammonia water, and most of the tar (about 60% - 70%) is condensed, and then is sucked into the gas purification workshop for purification treatment and at the same time chemical products are recovered.

[0004] The chemical products recovered from the coke oven raw gas usually include tar, crude benzene, naphthalene, hydrogen sulfide, ammonia, hydrogen cyanide, etc., all of which need to be effectively recovered. On the one hand, it increases economic value, and on the other hand, remaining in the gas will affect the combustion effect of the gas and increase pollution.

[0005] The patent document with the publication number of CN111285335A discloses a system and method for semi-dry preparation of sulfuric acid from sulfur foam and desulfurization waste liquid. The invention discloses a system and method for semi-dry preparation of sulfuric acid from sulfur foam and desulfurization waste liquid. The system is composed of a separation unit, an incineration unit, a purification unit, a drying and absorption unit, and a tail gas absorption unit connected in sequence. The invention extracts sulfur from sulfur foam, and the mixed salt is sent to the incinerator for incineration to produce sulfuric acid. After extracting sulfur and the mixed salt, the clarified liquid meets the requirements of returning to the desulfurization section for reuse and / or entering the cold drum section.

[0006] This method can obtain concentrated sulfuric acid with a concentration of 98%. The tail gas is well purified and the pollution degree is low. However, the overall process is relatively long, the energy consumption is large, the overall economic benefit is directly affected by the market price of sulfuric acid, and the clarified liquid after extracting sulfur and the mixed salt is directly returned to the desulfurization section without special treatment, which will affect the normal operation of the desulfurization section.

[0007] The patent document with publication number CN101092577A discloses a process and equipment for producing sulfuric acid from sulfur and waste liquid generated by wet oxidation desulfurization process of coal gas. Specifically, sulfuric acid is produced by using sulfur and waste liquid generated after wet oxidation desulfurization of coal gas as raw materials through five process steps: waste liquid incineration → waste heat recovery → dry purification → wet contact conversion → condensation. The process gas dry purification process is a newly developed acid production unit technology based on the characteristics of acid production raw materials, and the condensation process integrates the more advanced wet condensation acid production technology. The equipment includes incineration waste heat recovery dry purification wet contact conversion condensation equipment units. Compared with the existing acid production process, the invention reduces the two units of drying and tail gas detoxification. Dry purification has only one dry high-temperature purification dust collector, which simplifies the purification process flow. The annual total operating cost is only 33%, and there is no waste liquid discharge.

[0008] This patent adopts a wet process. The initial sulfur-containing solution has more impurities and needs to be purified to improve the purity of the subsequent sulfuric acid. The wet process will also bring about the problem of sulfuric acid corrosion, or improve the corrosion resistance of the equipment, which will undoubtedly increase investment. Utility Model Content

[0009] The utility model aims to solve at least one of the technical problems existing in the prior art. To this end, the utility model provides a device for purifying the clear liquid after sulfur melting, with the purpose of reducing costs.

[0010] In order to achieve the above-mentioned purpose, the technical solution adopted by the utility model is: a device for purifying the clear liquid after molten sulfur, including an oxidation tower for receiving the clear liquid of molten sulfur, a clear liquid tank connected to the oxidation tower, a centrifuge connected to the clear liquid tank and a heat exchanger connected to the centrifuge.

[0011] The heat exchanger is a spiral plate heat exchanger.

[0012] An air inlet is arranged on the oxidation tower, the oxidation tower is connected with a liquid inlet pipe, the molten sulfur clear liquid enters the oxidation tower through the liquid inlet pipe, and the air inlet is located above the liquid inlet pipe.

[0013] The distance between the air inlet and the liquid inlet pipe is 200-500 mm.

[0014] The air strength at the air inlet is 30 to 120 m 3 / (m 2 h).

[0015] A steam heater is provided at the bottom of the oxidation tower, and the steam heater maintains the temperature of the bottom of the oxidation tower at 110-130°C.

[0016] The oxidation tower, the clear liquid tank and the centrifuge are connected to a VOCs treatment device or a sulfur incinerator through a VOCs pipeline.

[0017] A clear liquid pump is arranged between the centrifuge and the heat exchanger.

[0018] For the device for purifying and treating the clear liquid after sulfur melting of the present utility model, the clear liquid tank connected to the oxidation tower can effectively reduce the impurity content of the clear liquid, and the required equipment cost is relatively low, thereby reducing the cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] This specification includes the following drawings, and the shown contents are respectively:

[0020] Figure 1 It is a schematic structural diagram of the device for purifying and treating the clear liquid after sulfur melting of the present utility model;

[0021] The marks in the figure are: 1, oxidation tower; 2, thermometer; 3, clear liquid tank; 4, centrifuge; 5, clear liquid pump; 6, heat exchanger; 7, VOCs pipeline. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022] Next, with reference to the drawings, through the description of the embodiments, the specific embodiments of the present utility model will be further described in detail. The purpose is to help those skilled in the art have a more complete, accurate and in-depth understanding of the concept and technical solution of the present utility model, and to facilitate its implementation.

[0023] As Figure 1 shown, the present utility model provides a device for purifying and treating the clear liquid after sulfur melting, which includes an oxidation tower 1 for receiving the clear liquid after sulfur melting, a clear liquid tank 3 connected to the oxidation tower 1, a centrifuge 4 connected to the clear liquid tank 3, and a heat exchanger 6 connected to the centrifuge 4.

[0024] Specifically, the present utility model relates to a device for the deep utilization of sulfides in the coking industry. The sulfuric acid production process is to purify, heat up, burn sulfur and sulfur-containing salt solutions produced by the previous process to generate sulfur dioxide, and finally absorb it with concentrated sulfuric acid through catalytic oxidation to produce qualified finished sulfuric acid. In the sulfur foam treatment process, the sulfur foam is first filtered and concentrated, then enters the sulfur melting device for sulfur melting, the produced liquid sulfur is sent to the incinerator for incineration, and the clear liquid after sulfur melting enters the oxidation tower 1 to separate a small amount of liquid sulfur and the upper clear liquid again. The present utility model mainly further processes the clear liquid after sulfur melting for further separation and purification.

[0025] In the present utility model, the clear liquid after sulfur melting from the sulfur melting kettle enters the oxidation tower 1, is heated by steam and oxidized by introducing air in the oxidation tower 1. The oxidized clear liquid is introduced into the clear liquid tank 3 for clarification and separation, then enters the centrifuge 4 for separation, and is pumped to the heat exchanger 6 and then sent to the desulfurization system through a pump, so as to improve the cleanliness of the returned liquid.

[0026] As Figure 1As shown in the figure, the oxidation tower 1 is connected to the feed pipe. The molten sulfur clarified liquid from the molten sulfur kettle enters the oxidation tower 1 through the feed pipe for impurity removal. A steam heater is provided at the bottom of the oxidation tower 1, and the steam heater maintains the temperature at the bottom of the oxidation tower 1 at 110 - 130 °C.

[0027] As Figure 1 shown in the figure, an air inlet is provided on the oxidation tower 1. The air inlet is located above the feed pipe, and the distance between the air inlet and the feed pipe is 200 - 500 mm. The purpose of air entering the oxidation tower 1 is to oxidize thiosulfate in the molten sulfur clarified liquid into sulfur and sulfate, thereby reducing the re - entry of thiosulfate into the desulfurization system. At the same time, the entry of air can also play a flotation role, effectively separating sulfur slag from the molten sulfur clarified liquid.

[0028] Preferably, the air intensity supplied into the oxidation tower 1 through the air inlet is 30 - 120 m 3 / (m 2 ·h), which not only plays an oxidation role but also can play a certain flotation role.

[0029] As Figure 1 shown in the figure, the bottom of the oxidation tower 1 is connected to the incinerator. A small amount of liquid sulfur obtained at the lower part after purification of the oxidation tower 1 is led out and sent to the incinerator for combustion when the temperature at the bottom of the oxidation tower 1 rises to 120 - 130 °C. The remaining supernatant liquid in the oxidation tower 1 then enters the clarified liquid tank 3 for clarification and static settlement.

[0030] As Figure 1 shown in the figure, the upper side of the clarified liquid tank 3 has a side - line opening. There are still some impurities in the upper - layer clarified liquid, which need to be further treated by filtration through the centrifuge 4, and it can also reduce the impact of sulfur particles contained on the performance of the subsequent desulfurization system.

[0031] As Figure 1 shown in the figure, the tops of the oxidation tower 1, the clarified liquid tank 3, and the centrifuge 4 are connected to the VOCs treatment device or the sulfur incinerator through the VOCs pipeline 7. The generated VOCs gas is introduced into the VOCs treatment device for treatment and discharged up to standard, or it can also be directly introduced into the sulfur incinerator to be burned. Preferably, the method of introducing it into the incinerator to be burned is adopted.

[0032] As Figure 1 shown in the figure, a clarified liquid pump 5 is provided between the centrifuge 4 and the heat exchanger 6. One end of the clarified liquid pump 5 is connected to the centrifuge 4, and the other end of the clarified liquid pump 5 is connected to the heat exchanger 6. The temperature of the upper - layer clarified liquid is relatively high after filtration by the centrifuge 4. Directly pumping it to the desulfurization system will affect the stability of the desulfurization system. Therefore, a cooling device is added. The heat exchanger 6 is used for cooling. The heat exchanger 6 is preferably a spiral plate heat exchanger. The heat exchanger 6 is connected to the desulfurization unit. The clarified liquid pump 5 sends the centrifuged clarified liquid to the heat exchanger 6 for heat exchange and cooling, and after the temperature is reduced to 30 - 45 °C, it is sent to the reaction tank of the desulfurization section to re - enter the desulfurization liquid circulation process.

[0033] As Figure 1 shown, the sediment at the bottom of the clarified liquid tank 3 is regularly emptied and sent to the coal yard for treatment after pressure filtration, and the filter residue after filtration by the centrifuge 4 is also sent to the coal yard for treatment.

[0034] The device for purifying the clarified liquid after sulfur melting with the above structure has the following advantages:

[0035] 1. If the clarified liquid from the oxidation tower 1 is not directly treated, it will significantly affect the normal operation of the desulfurization unit. The clarified liquid tank 3 can effectively reduce the impurity content of the clarified liquid, and the required equipment cost is relatively low.

[0036] 2. If the fine sulfur particles contained in the clarified liquid directly enter the desulfurization unit, it will cause foaming in the desulfurization unit and increase side reactions. Therefore, adding a centrifugal filtration device can effectively stabilize the operation of the desulfurization and further reduce the impurity content.

[0037] 3. Since the desulfurization unit uses desulfurization catalysts such as biological complex iron and PDS, it requires a suitable catalytic temperature and to better absorb sulfur in the coal gas, the system temperature needs to be controlled. Therefore, the clarified liquid is cooled by a cooling device after filtration.

[0038] 4. In the present utility model, an air inlet is provided at a position 200 - 500 mm above the inlet of the molten sulfur clarified liquid in the oxidation tower 1, which can make the heavy liquid sulfur in the molten sulfur clarified liquid settle naturally, avoiding the heavy liquid sulfur in the clarified liquid being brought into the next clarified liquid sedimentation process, that is, the clarified liquid tank 3, after air introduction. At the same time, the ammonium thiosulfate salt in the clarified liquid can be further oxidized into sulfur and sulfate, which is beneficial to the further removal of sulfur in the molten sulfur clarified liquid. At the same time, it is beneficial to further float and enrich the fine sulfur particles in the clarified liquid, so as to facilitate re-sedimentation and separation in the subsequent clarified liquid tank 3 and filtration and precipitation in the centrifuge 4.

[0039] 5. In the present utility model, a centrifuge 4 is installed in front of the molten sulfur clarified liquid cooling heat exchanger 6 to filter the sulfur particles and impurities in the clarified liquid, which is beneficial to reducing the blockage of the heat exchanger 6 and extending the maintenance cycle of the equipment.

[0040] 6. The VOCs gas at the top of the oxidation tower 1 and the clarified liquid tank 3 is directly introduced into the sulfur incinerator for combustion, which is beneficial to environmental protection and up-to-standard discharge, and reduces the investment and operation costs of building a separate VOCs treatment device.

[0041] The present utility model has been described exemplarily in combination with the accompanying drawings. Obviously, the specific implementation of the present utility model is not limited by the above methods. As long as various non-substantive improvements are made by adopting the method concept and technical solution of the present utility model; or without improvement, the above concept and technical solution of the present utility model are directly applied to other occasions, they are all within the protection scope of the present utility model.

Claims

1. A device for purifying the clear liquid after sulfur melting, characterized in that: The invention comprises an oxidation tower for receiving molten sulfur clear liquid, a clear liquid tank connected with the oxidation tower, a centrifuge connected with the clear liquid tank and a heat exchanger connected with the centrifuge.

2. The device for purifying the clear liquid after molten sulfur according to claim 1, characterized in that: The heat exchanger is a spiral plate heat exchanger.

3. The device for purifying the clear liquid after sulfur melting according to claim 1 is characterized in that: An air inlet is arranged on the oxidation tower, the oxidation tower is connected with a liquid inlet pipe, the molten sulfur clear liquid enters the oxidation tower through the liquid inlet pipe, and the air inlet is located above the liquid inlet pipe.

4. The device for purifying the clear liquid after sulfur melting according to claim 3 is characterized in that: The distance between the air inlet and the liquid inlet pipe is 200-500 mm.

5. The device for purifying the clear liquid after sulfur melting according to claim 3 is characterized in that: The air strength at the air inlet is 30 to 120 m 3 / (m 2 h).

6. The device for purifying the clear liquid after sulfur melting according to any one of claims 1 to 5, characterized in that: A steam heater is provided at the bottom of the oxidation tower, and the steam heater maintains the temperature of the bottom of the oxidation tower at 110-130°C.

7. The device for purifying the clear liquid after sulfur melting according to any one of claims 1 to 5, characterized in that: The oxidation tower, the clear liquid tank and the centrifuge are connected to a VOCs treatment device or a sulfur incinerator through a VOCs pipeline.

8. The device for purifying the clear liquid after sulfur melting according to any one of claims 1 to 5, characterized in that: A clear liquid pump is arranged between the centrifuge and the heat exchanger.

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