阅读说明：本技术 一种利用废热氧化蒸发结晶回收硫酸钠的系统 (System for utilize waste heat oxidation evaporation crystallization to retrieve sodium sulfate ) 是由 李树民 于 2019-09-24 设计创作，主要内容包括：本发明提供一种利用废热氧化蒸发结晶回收硫酸钠的系统,包括燃硫单元、转化单元、蒸汽热水单元和蒸发结晶单元,燃硫单元和转化单元产生的热风汇集于热风输送管,热风输送管依次与蒸汽热水单元和蒸发结晶单元相连,或者热风输送管分别与蒸汽热水单元和蒸发结晶单元相连,蒸发结晶单元由蒸发塔、碱吸收液循环槽和碱吸收液循环泵组成,蒸发塔一侧的下端设有热风入口,热风输送管输送的热风经蒸汽热水单元降温后经热风入口进入蒸发塔,或者热风输送管输送的热风直接经热风入口进入蒸发塔。本发明回收燃硫和SO<Sub>2</Sub>转化的反应热产生热空气,进而产生蒸汽用于熔硫、产热水用于伴热,剩余热风则用于含硫酸钠及亚硫酸钠吸收液的氧化蒸发结晶。(The invention provides a system for recovering sodium sulfate by utilizing waste heat oxidation evaporative crystallization, which comprises a sulfur burning unit, a conversion unit, a steam hot water unit and an evaporative crystallization unit, wherein hot air generated by the sulfur burning unit and the conversion unit is collected in a hot air conveying pipe, the hot air conveying pipe is sequentially connected with the steam hot water unit and the evaporative crystallization unit, or the hot air conveying pipe is respectively connected with the steam hot water unit and the evaporative crystallization unit, the evaporative crystallization unit consists of an evaporation tower, an alkali absorption liquid circulating tank and an alkali absorption liquid circulating pump, the lower end of one side of the evaporation tower is provided with a hot air inlet, hot air conveyed by the hot air conveying pipe is cooled by the steam hot water unit and then enters the evaporation tower through the hot air inlet, or hot air conveyed by the hot air conveying pipe directly enters. The invention recovers the combustion sulfur and SO 2 The heat of reaction of the conversion produces hot air,and further generating steam for melting sulfur, generating hot water for heat tracing, and using residual hot air for oxidation evaporation crystallization of absorption liquid containing sodium sulfate and sodium sulfite.)

1. A system for recovering sodium sulfate by utilizing waste heat oxidation evaporation crystallization is characterized by comprising a sulfur burning unit, a conversion unit, a steam hot water unit and an evaporation crystallization unit, the hot air generated by the sulfur burning unit and the conversion unit is collected in a hot air conveying pipe, the hot air conveying pipe is sequentially connected with the steam hot water unit and the evaporation crystallization unit, or the hot air delivery pipe is respectively connected with the steam hot water unit and the evaporative crystallization unit, the evaporation crystallization unit consists of an evaporation tower, an alkali absorption liquid circulating tank and an alkali absorption liquid circulating pump, the lower end of one side of the evaporation tower is provided with a hot air inlet, hot air conveyed by the hot air conveying pipe enters the evaporation tower through the hot air inlet after being cooled by the steam hot water unit, or the hot air conveyed by the hot air conveying pipe directly enters the evaporation tower through the hot air inlet.

2. The system for recovering sodium sulfate by utilizing waste heat oxidation, evaporation and crystallization as claimed in claim 1, wherein the sulfur burning unit comprises a sulfur melting tank, a sulfur burning furnace, and SO₂A cooler, a start-up furnace and a pre-heating fan, wherein the sulfur melting tank, the sulfur burning furnace and the SO₂The coolers are connected in sequence, sulfur is melted in the sulfur melting tank and then enters the sulfur burning furnace to be fully combusted with air, and the generated SO₂Flue gas entering the SO₂The cooler carries out heat exchange and cooling.

3. A method according to claim 2The system for recovering sodium sulfate by utilizing waste heat oxidation, evaporation and crystallization is characterized in that the conversion unit comprises a converter, a primary cooler and a first SO₃Cooler, second SO₃A cooler and a cooling fan, the converter and the first SO₃Cooler and the second SO₃Coolers are connected in sequence, the SO₂Cooled SO from cooler₂The flue gas enters the converter for catalytic conversion to generate SO₃-air mixture entering said first SO in sequence₃Cooler and the second SO₃The cooler exchanges heat and cools, and the cold air fan is used for cooling the section of cooler and the first SO₃Cooler and the second SO₃The cooler conveys air, and the air is collected in the hot air conveying pipe after heat exchange and heating.

4. The system for recovering sodium sulfate by utilizing waste heat oxidation, evaporation and crystallization as claimed in claim 3, wherein an outlet of the preheating fan is connected with the start-up furnace, an outlet of the cold air fan is also connected with the start-up furnace, and the top of the start-up furnace is connected with the SO₂The cooler is connected, and the gas discharged by the start-up furnace passes through the SO₂The heated air is collected in the hot air delivery pipe.

5. The system for recovering sodium sulfate by utilizing waste heat oxidation evaporative crystallization according to claim 3, wherein a circulation cooling inlet pipe and a circulation cooling outlet pipe are arranged in the middle of one side of the converter, and the circulation cooling inlet pipe and the circulation cooling outlet pipe are connected with the primary cooler.

6. The system for recovering sodium sulfate by utilizing waste heat oxidation, evaporation and crystallization according to claim 5, wherein the steam-hot water unit comprises a heat pipe heat exchanger, a preheater, a pure water tank, a pure water delivery pump, a steam generator, a hot water tank and a hot water circulating pump, the hot air delivery pipe is connected with an inlet of the heat pipe heat exchanger, and hot air passing through the heat pipe heat exchanger passes through the preheater and the hot water generator in sequence for heat exchange and cooling.

7. The system for recovering sodium sulfate by utilizing waste heat oxidation, evaporation and crystallization according to claim 6, wherein the hot water generator and the preheater are arranged in the same device from top to bottom, the preheater is provided with a first heating inlet and a first heating outlet, an inlet of the pure water delivery pump is connected with the pure water tank, an outlet of the pure water delivery pump is connected with the first heating inlet, and the first heating outlet is sequentially connected with the steam generator and the sulfur melting tank through pipelines.

8. The system for recovering sodium sulfate by utilizing waste heat oxidation, evaporation and crystallization according to claim 7, wherein the hot water generator is further provided with a second heating inlet and a second heating outlet, the inlet of the hot water circulating pump is connected with the hot water tank, the outlet of the hot water circulating pump is connected with the second heating inlet, and the second heating outlet is connected with the heat tracing device through a pipeline.

9. The system for recovering sodium sulfate by utilizing waste heat oxidation, evaporation and crystallization according to claim 1, characterized in that a spray pipe is arranged in the evaporation tower, an emptying pipe and a liquid discharge pipe are respectively arranged at the top and the bottom of the evaporation tower, an outlet of the liquid discharge pipe is positioned in the alkali absorption liquid circulation tank, an inlet of the alkali absorption liquid circulation pump is connected with the lower end of the alkali absorption liquid circulation tank through a pipeline, and an outlet of the alkali absorption liquid circulation pump is connected with the spray pipe through a pipeline.

Technical Field

The invention belongs to SO₃The technical field of membrane type sulfonation, in particular to a system for recovering sodium sulfate by utilizing waste heat oxidation, evaporation and crystallization.

Background

In the tail gas treatment stage in the sulfur trioxide film type sulfonation technology, a sodium hydroxide solution is generally adopted to absorb sulfur dioxide in the tail gas, so that the tail gas reaches the emission standard, 13-14 ten thousand tons of waste liquid is generated every year in China, the waste liquid is free of trace surfactant components capable of being automatically degraded in the environment, the main component is 10% (wt%) sodium sulfate-sodium sulfite mixed salt, if the waste liquid cannot be further effectively treated, the discharged waste liquid can cause the problems of dissolved oxygen consumption in a water body, aggravation of land salinization degree and the like, and in addition, the traditional sulfonation technology has low utilization rate of waste heat. Therefore, in view of the above disadvantages, there is a need for a system for recovering sodium sulfate by waste heat deoxidation, evaporation, crystallization, and utilization of the device itself, which can effectively utilize waste heat, reduce the Chemical Oxygen Demand (COD) in the waste liquid, and recycle sodium sulfate in the waste liquid, thereby reducing the discharge of the waste liquid.

Disclosure of Invention

The invention aims to provide a system for recovering sodium sulfate by utilizing waste heat oxidation, evaporation and crystallization, and the device is used for recovering combustion sulfur and SO₂The converted reaction heat generates hot air, further generates steam for melting sulfur and hot water for heat tracing, and the residual hot air is used for oxidizing, evaporating and crystallizing absorption liquid containing sodium sulfate and sodium sulfite discharged by the alkaline tower to generate mirabilite with commercial value, so that the method has higher economic benefit and environmental benefit.

The invention provides the following technical scheme:

a system for recovering sodium sulfate by utilizing waste heat oxidation evaporation crystallization comprises a sulfur burning unit, a conversion unit, a steam hot water unit and an evaporation crystallization unit, the hot air generated by the sulfur burning unit and the conversion unit is collected in a hot air conveying pipe, the hot air conveying pipe is sequentially connected with the steam hot water unit and the evaporation crystallization unit, or the hot air delivery pipe is respectively connected with the steam hot water unit and the evaporative crystallization unit, the evaporation crystallization unit consists of an evaporation tower, an alkali absorption liquid circulating tank and an alkali absorption liquid circulating pump, wherein the alkali absorption liquid is absorption liquid containing sodium sulfate and sodium sulfite discharged by the alkali washing tower, the lower end of one side of the evaporation tower is provided with a hot air inlet, hot air conveyed by the hot air conveying pipe enters the evaporation tower through the hot air inlet after being cooled by the steam hot water unit, or the hot air conveyed by the hot air conveying pipe directly enters the evaporation tower through the hot air inlet.

Preferably, the sulfur burning unit consists of a sulfur melting tank, a sulfur burning furnace and SO₂A cooler, a start-up furnace and a pre-heating fan, wherein the sulfur melting tank, the sulfur burning furnace and the SO₂The coolers are connected in sequence, sulfur is melted in the sulfur melting tank and then enters the sulfur burning furnace to be fully combusted with air, and the generated SO₂Flue gas entering the SO₂The cooler carries out heat exchange and cooling.

Preferably, the conversion unit consists of a converter, a primary cooler, a first SO₃Cooler, second SO₃A cooler and a cooling fan, the converter and the first SO₃Cooler and the second SO₃Coolers are connected in sequence, the SO₂Cooled SO from cooler₂The flue gas enters the converter for catalytic conversion to generate SO₃-air mixture entering said first SO in sequence₃Cooler and the second SO₃The cooler exchanges heat and cools, and the cold air fan is used for cooling the section of cooler and the first SO₃Cooler and the second SO₃The cooler conveys air, and the air is collected in the hot air conveying pipe after heat exchange and heating.

Preferably, the outlet of the preheating fan is connected with the work starting furnace, the outlet of the cold air fan is also connected with the work starting furnace, and the top of the work starting furnace is connected with the SO₂The cooler is connected, and the gas discharged by the start-up furnace passes through the SO₂The heated air is collected in the hot air delivery pipe.

Preferably, a circulating cooling inlet pipe and a circulating cooling outlet pipe are arranged in the middle of one side of the converter and are connected with the first section of cooler.

Preferably, the steam hot water unit comprises a heat pipe heat exchanger, a preheater, a pure water tank, a pure water delivery pump, a steam generator, a hot water tank and a hot water circulating pump, the hot air delivery pipe is connected with an inlet of the heat pipe heat exchanger, and hot air passing through the heat pipe heat exchanger sequentially passes through the preheater and the hot water generator for heat exchange and cooling.

Preferably, the hot water generator and the preheater are arranged in the same device from top to bottom, the preheater is provided with a first heating inlet and a first heating outlet, an inlet of the pure water delivery pump is connected with the pure water tank, an outlet of the pure water delivery pump is connected with the first heating inlet, and the first heating outlet is sequentially connected with the steam generator and the sulfur melting tank through pipelines.

Preferably, the hot water generator is further provided with a second heating inlet and a second heating outlet, the inlet of the hot water circulating pump is connected with the hot water tank, the outlet of the hot water circulating pump is connected with the second heating inlet, and the second heating outlet is connected with the heat tracing device through a pipeline.

Preferably, a spray pipe is arranged in the evaporation tower, an emptying pipe and a liquid discharge pipe are respectively arranged at the top and the bottom of the evaporation tower, an outlet of the liquid discharge pipe is positioned in the alkali absorption liquid circulation tank, an inlet of the alkali absorption liquid circulation pump is connected with the lower end of the alkali absorption liquid circulation tank through a pipeline, and an outlet of the alkali absorption liquid circulation pump is connected with the spray pipe through a pipeline.

The invention has the beneficial effects that:

in the using process of the invention, the sulfur is melted in the sulfur melting tank and then enters the sulfur burning furnace for full combustion, and the generated SO₂Passing flue gas over SO₂After part of heat is recovered by the cooler, the cooled gas enters the converter and reacts with dry air to generate SO under the action of a vanadium-based catalyst₃Air mixed gas, SO₃After the air mixed gas is cooled for multiple times to recover heat, the air mixed gas enters a membrane type sulfonation reactor to react, the generated tail gas is absorbed by a sodium hydroxide solution, and the generated alkali absorption liquid is input into an alkali absorption liquid circulation tank; SO (SO)₂Cooler, first stage cooler, first SO₃Cooler and second SO₃Cooler for recovering combustion sulfur and SO₂The conversion reaction heat generates hot air, the hot air is collected in a hot air conveying pipe and then enters a heat pipe exchanger, the hot air after heat exchange is subjected to partial heat recovery by a preheater and then is generated by a steam generatorThe steam is used for melting solid sulfur in the sulfur melting tank, part of heat is used for heat tracing of the heat tracing device by hot water generated by the hot water generator, and the rest of heat is provided for the evaporation tower by hot air to be used for oxidation, evaporation and crystallization of the alkali absorption liquid, so that mirabilite is purified and produced, and can be sold as an industrial product, thereby bringing extra income to enterprises; by utilizing the process, the recovery heat is about 3.04 ten thousand tons of standard coal per year (the thermal efficiency is 90 percent), the yield of the generated mirabilite is 2.5 ten thousand tons per year, the economic benefit is improved, the discharge of a large amount of sewage can be reduced, and the environmental benefit is higher.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:

FIG. 1 is a schematic view of the constitution of example 1 of the present invention;

FIG. 2 is a process flow diagram of example 1 of the present invention;

FIG. 3 is a schematic view of the constitution of example 2 of the present invention.

Labeled as: 1. a sulfur burning unit; 11. a sulfur melting tank; 12. a sulfur furnace; 13. SO (SO)₂A cooler; 14. starting up the furnace; 15. preheating a fan; 2. a conversion unit; 21. a converter; 211. a circulating cooling inlet pipe; 212. a circulating cooling outlet pipe; 22. a first stage cooler; 23. first SO₃A cooler; 24. second SO₃A cooler; 25. a cooling fan; 26. a hot air delivery pipe; 3. a steam hot water unit; 31. a heat pipe heat exchanger; 32. a preheater; 321. a first heating inlet; 322. a first heating outlet; 33. a pure water tank; 34. a pure water delivery pump; 35. a steam generator; 36. a hot water generator; 361. a second heating inlet; 362. a second heating outlet; 37. a hot water tank; 38. a hot water circulation pump; 39. a heat tracing device; 391. a cooling water outlet; 4. an evaporative crystallization unit; 41. an evaporation tower; 411. a hot air inlet; 412. a shower pipe; 413. emptying the pipe; 414. a liquid discharge pipe; 42. an alkali absorption liquid circulation tank; 43. alkali absorption liquid circulating pump.

Detailed Description