Containing SO2Method for preparing sulfur from flue gas
阅读说明：本技术 一种含so2的烟气制备硫磺的方法 (Containing SO2Method for preparing sulfur from flue gas ) 是由 秦赢 董四禄 魏甲明 姚亮 牛江舸 于 2021-05-06 设计创作，主要内容包括：本发明涉及一种含SO-2的烟气制备硫磺的方法,包括以下步骤：(1)二氧化硫的还原；(2)高温收尘；(3)高温转化制硫磺工段；(4)低温还原工段；(5)硫磺的脱气与造粒；(6)尾气脱硫。该方法在解决二氧化硫排放引起的环境问题以外,回收硫资源,保证硫磺品质,变废为宝。同时降低二氧化硫制硫磺的生产成本,工艺简单、经济高效。(The invention relates to a method for preparing a sulfur-containing organic compound 2 The method for preparing the sulfur by using the flue gas comprises the following steps: (1) reducing sulfur dioxide; (2) collecting dust at high temperature; (3) a sulfur preparation section by high-temperature conversion; (4) a low-temperature reduction section; (5) degassing and granulating the sulfur; (6) and (4) tail gas desulfurization. The method can recover sulfur resources, ensure sulfur quality, and change waste into valuable in addition to solving the environmental problem caused by sulfur dioxide emission. Meanwhile, the production cost of sulfur produced by sulfur dioxide is reduced, and the process is simple, economic and efficient.)
1. Containing SO2The method for preparing the sulfur by using the flue gas is characterized by comprising the following steps of:
(1) reduction of sulfur dioxide: the high-temperature smelting flue gas discharged from the electric dust collector or the active coke desorption flue gas of the power plant directly enters a reduction reactor to perform reduction reaction with coal to generate reducing gas;
(2) high-temperature dust collection: reducing gas from the reduction reactor enters a high-efficiency dust collector for high-temperature dust collection so as to remove impurities such as coal ash in the flue gas;
(3) a high-temperature conversion sulfur production section: mixing the reducing gas subjected to high-efficiency dust collection in the step (2) with air or pure oxygen, feeding the mixture into a conversion reactor, reacting to generate flue gas containing sulfur, and cooling and condensing to obtain liquid sulfur and mixed flue gas;
(4) a low-temperature reduction section: the mixed flue gas is heated by a reheater and entersA low-temperature reduction reactor for reducing the residual SO in the mixed flue gas2And H2S is converted into sulfur, and after the sulfur is recovered by a condenser, tail gas is burnt;
(5) degassing and granulating sulfur: degassing and granulating the sulfur obtained in the steps (3) and (4) to obtain a sulfur product;
(6) tail gas desulfurization: and (5) desulfurizing and discharging the tail gas of the steps (4) and (5).
2. The method of claim 1, wherein the temperature of the reduction reaction with coal in step (1) is 1000 ℃ to 1200 ℃.
3. The method according to claim 1, wherein the reducing gas from the reduction reactor in the step (2) is cooled to 500-600 ℃ through a gas-gas heat exchanger, and then enters the high-temperature dust collector, and the dust content of the flue gas at the flue gas outlet after passing through the high-temperature dust collector is not more than 20mg/Nm3。
4. The process of claim 1, wherein the reaction temperature of the conversion reactor in step (3) is from 1000 ℃ to 1200 ℃.
5. The method according to claim 1, wherein the sulfur-containing flue gas in the step (3) is cooled to 250-350 ℃ by a waste heat boiler, and then is cooled and condensed to obtain liquid sulfur and mixed flue gas.
6. The method as claimed in claim 1, wherein the reaction temperature of the low-temperature reduction section in the step (4) is 250 ℃ to 350 ℃.
7. The method according to claim 1, wherein the low-temperature reduction section in the step (4) is a primary low-temperature reduction.
8. The method as claimed in claim 1, wherein the low-temperature reduction section in the step (4) is a secondary low-temperature reduction.
Technical Field
The invention relates to the technical field of flue gas treatment, in particular to a flue gas containing SO2The method for preparing sulfur by using the flue gas.
Background
Containing SO2The flue gas of (2) is mostly prepared by a process scheme for preparing sulfuric acid at present. For special areas or special needs of owners, a sulfur production process can be considered.
SO2The sulfur production technology mainly comprises a direct reduction method and an indirect reduction method at present, wherein the indirect reduction method has no industrial production practice case.
The direct reduction method uses hydrogen, natural gas, carbon, CO, water gas and the like as reducing agents and SO2Directly reduced into elemental sulfur. According to the reducing agent, H can be classified2Reduction method, carbon reduction method, CH4Reduction, CO reduction, and water gas reduction. It has been put to practical use at present that4The reduction method, which is applied industrially in the world, is only 1 case of the Russian Norreck smelting plant, and the system has the problems of high cost, low operating rate and the like.
The indirect reduction method is mainly SO developed by WorleyParsons company2The principle of the reduction process is to react CH4Reaction with sulfur vapour to CS2Then CS2Hydrolysis to H2S，H2S and SO2The claus reaction is carried out to produce sulfur, but there is no complete commercial practice.
The invention patent CN 105502302B discloses a method and a system for preparing sulfur from smelting flue gas, and the technology adopts pure SO2The sulfur is prepared by reacting with a reducing agent, and the complex smoke is prepared into pure SO by a conventional adsorption and desorption process due to complex components and low concentration of the smelting smoke2A large amount of steam must be consumed, so that the operation cost is greatly increased.
The invention patent CN 103303872B discloses a system device and a method for recovering sulfur dioxide from flue gas to prepare sulfur, the technology adopts three units of absorption pyrolysis, reduction and Claus, and pure SO is prepared firstly2。
The invention patent CN 106467293B discloses a method for preparing sulfur and a system device for preparing sulfur, and the technology provides 1 reduction furnace +1 catalytic reduction furnace, and 1-99% SO is added by using various reducing agents such as coal2Reducing to prepare sulfur. Has the problems that the influence of various components and impurities in the smelting flue gas on the reaction is not considered, and simultaneously, the influence of byproducts possibly generated by the reduction reaction on the subsequent process is not considered,there is no effective countermeasure.
The invention patent CN 209226582U discloses a SO2The two-stage boiling reduction device for preparing sulfur by smelting flue gas mainly comprises a two-stage boiling reduction furnace, a cyclone dust collector, a waste heat boiler, a filter cartridge dust collector, a sulfur condenser, ionic liquid desulfurization and the like, and has the problems that the influence of various components and impurities in the smelting flue gas on the reaction is not considered, the influence of ash content in the product after the reaction of the two-stage reduction furnace and other impurities in the flue gas on the product quality is not taken into consideration, the sulfur recovery rate after primary reduction is not given, and the part cannot be high according to theoretical calculation, SO the ionic liquid desulfurization is carried out after primary reduction in the original process route, and SO is used for desulfurizing2Returning to the front end to participate in the reaction again tends to increase energy consumption.
The invention patent CN 111704113B discloses a method for preparing sulfur from complex concentrate smelting flue gas, which mainly aims at complex smelting flue gas containing more toxic and harmful components such As As, F, Cl, Pb, Cd, Cr and the like, and adopts flue gas washing and purification, and then the flue gas reacts with coal to produce qualified sulfur products.
SO content for smelting industry2The flue gas, which is smelting flue gas usually containing a large amount of toxic and harmful components such as arsenic, Pd, Cd, Cr, fluorine and the like, is usually purified and washed to ensure the quality of sulfur products. If the smelted concentrate does not contain harmful components such as arsenic, fluorine and the like, the smelting smoke does not contain the harmful impurities, if a smoke purification route is still adopted, heat loss is caused, and more heat is consumed for reheating the smoke; in addition, in the power industry, limestone-gypsum method is generally adopted for desulfurization, and processes of desulfurization by using ionic liquid, active coke and the like are also adopted, and when the active coke desulfurization process is adopted, high-concentration SO after desorption is generally adopted2The smoke gas does not contain the harmful impurities.
Among other prior art, there are processes that use coal reduction, but use pure SO2The gas participates in the reduction reaction, and the method needs to consume a large amount of energy to prepare pure SO2Resulting in very high production costs。
Therefore, most of the defects of the prior art are high energy consumption, and most of the process routes adopt pure SO2Or subsequently adopting ionic liquid to desulfurize and produce partial SO2This greatly increases the consumption of low-pressure steam and thus the energy consumption of the entire system, and therefore, it is required to develop a SO-containing steam2The novel method for preparing sulfur by using the flue gas.
Disclosure of Invention
Accordingly, the present invention has been made keeping in mind the above problems. It is an object of the present invention to provide an SO-containing composition free of harmful impurities2The method for preparing sulfur by using the flue gas. The method can recover sulfur resources, ensure sulfur quality, and change waste into valuable in addition to solving the environmental problem caused by sulfur dioxide emission. Meanwhile, the production cost of sulfur produced by sulfur dioxide is reduced, and the process is simple, economic and efficient.
In order to achieve the above object, the present invention provides an SO-containing gas composition free of harmful impurities2The method for preparing the sulfur by using the flue gas comprises the following steps:
(1) reduction of sulfur dioxide: the high-temperature smelting flue gas discharged from the electric dust collector or the active coke desorption flue gas of the power plant directly enters a reduction reactor to perform reduction reaction with coal to generate reducing gas;
(2) high-temperature dust collection: reducing gas from the reduction reactor enters a high-efficiency dust collector for high-temperature dust collection so as to remove impurities such as coal ash in the flue gas;
(3) a high-temperature conversion sulfur production section: mixing the reducing gas subjected to high-efficiency dust collection in the step (2) with air or pure oxygen, feeding the mixture into a conversion reactor, reacting to generate flue gas containing sulfur, and cooling and condensing to obtain liquid sulfur and mixed flue gas;
(4) a low-temperature reduction section: heating the mixed flue gas by a reheater, feeding the heated mixed flue gas into a low-temperature reduction reactor, and adding the residual SO in the mixed flue gas2And H2S is converted into sulfur, and after the sulfur is recovered by a condenser, tail gas is burnt;
(5) degassing and granulating sulfur: degassing and granulating the sulfur obtained in the steps (3) and (4) to obtain a sulfur product;
(6) tail gas desulfurization: and (5) desulfurizing and discharging the tail gas of the steps (4) and (5).
Further, the temperature of the reduction reaction with the coal in the step (1) is 1000-1200 ℃.
Further, in the step (2), the reducing gas discharged from the reduction reactor is cooled to 500-600 ℃ through a gas-gas heat exchanger, then enters the high-temperature dust collector, and the dust content of a flue gas outlet after passing through the high-temperature dust collector is not more than 20mg/Nm3。
Further, the reaction temperature of the conversion reactor in the step (3) is 1000-1200 ℃.
Further, the temperature of the flue gas containing sulfur in the step (3) is reduced to 250-350 ℃ through a waste heat boiler, and then liquid sulfur and mixed flue gas are obtained after temperature reduction and condensation.
Further, the reaction temperature of the low-temperature reduction section in the step (4) is 250-350 ℃.
Further, the low-temperature reduction section in the step (4) is a first-stage low-temperature reduction.
Further, the low-temperature reduction section in the step (4) is a two-stage low-temperature reduction.
Compared with the prior art, the invention has the beneficial effects that:
one of the objectives of the invention is to reduce the energy consumption as much as possible, in relation to SO-containing gases without harmful impurities2The flue gas is not washed and purified by adopting the flue gas, but the high-temperature flue gas after an electric dust collector or after active coke desorption is directly sent into a reduction reactor to directly react with coal, and the flue gas is directly reduced to produce sulfur by controlling the addition of the coal, oxygen and the like and the component detection of a product and other measures, so that the consumption of fuel for cooling and then heating the flue gas is saved; secondly, the amount of the coal and the oxygen is controlled, the operation cost is reduced, and qualified sulfur products are produced. Therefore, the purposes of reducing energy consumption, improving the utilization rate of coal and reducing production cost are achieved.
The SO-containing material of the present invention is free of harmful impurities2The method for preparing the sulfur by using the flue gas has the following characteristics:
1. the flue gas containing arsenic and fluorine is not purified any more, and the high-temperature flue gas is directly used for a reduction reactor;
2. multi-component flue gas (SO)2\O2\CO2\H2O, etc., minor amounts of arsenic, fluorine) directly with coal, rather than a single component;
3. mixing the reducing flue gas subjected to high-efficiency dust collection with air or pure oxygen, feeding the mixture into a conversion reactor, reacting to generate sulfur, and subsequently reducing at low temperature to further improve the yield of the sulfur;
4. the method has high sulfur recovery rate, and the SO is returned if the ionic liquid or active coke desulfurization process is adopted2The recovery rate can reach more than 99%.
Thus, the SO-containing compositions of the invention are free of deleterious impurities2The method for preparing the sulfur by the flue gas has the advantages of high product quality and less impurities; the heat utilization rate is high; the steam consumption is low; and the superior technical effect of low operation cost.
Drawings
FIG. 1 shows SO-containing according to one embodiment of the present invention2The flow chart of the method for preparing sulfur by using the flue gas.
Detailed Description
The present invention is further described in detail below by way of examples to enable those skilled in the art to understand the present invention, and the examples are only for explaining the present invention and do not limit the scope of the present invention.
The invention conception of the invention is as follows: aiming at smelting flue gas containing arsenic and fluorine, the smelting flue gas containing arsenic and fluorine is not washed and cooled, but high-temperature flue gas is directly sent to a reduction reactor to be subjected to reduction reaction with coal to generate reducing gas such as hydrogen sulfide and the like, the reducing flue gas is mixed with air or pure oxygen to be subjected to oxidation reduction reaction to generate sulfur and carbon dioxide after high-temperature dust collection, and the flue gas is condensed to obtain a sulfur product.
The invention relates to a SO-containing material without harmful impurities2The method for preparing sulfur from flue gas relates to a method for recovering sulfur dioxide from smelting flue gas containing less arsenic and fluorine to prepare sulfur, and a desulfurization method for recovering sulfur dioxide from flue gas to prepare sulfur comprises the following steps: (1) SO (SO)2Reducing at high temperature; (2) Collecting dust at high temperature; (3) converting at high temperature to prepare sulfur; (4) reducing at low temperature; (5) condensing and granulating to prepare sulfur; (6) and (4) tail gas desulfurization. The SO content is described in detail below2The method for preparing the sulfur by the flue gas comprises the following steps:
(1) reduction of sulfur dioxide: the high-temperature smelting flue gas from the electric dust collector or the active coke desorption flue gas from the power plant directly enters a reduction reactor to perform reduction reaction with coal to generate sulfur-containing hydrogen, COS and CS2And the like. The reaction temperature of the reduction reaction with coal is 1000-1200 ℃.
SO content for smelting industry2The flue gas is smelting flue gas which usually contains a large amount of toxic and harmful components such as arsenic, Pd, Cd, Cr, fluorine and the like. If the smelted concentrate does not contain harmful components such as arsenic, fluorine and the like, the smelting flue gas does not contain the harmful impurities; in addition, in the power industry, limestone-gypsum method is generally adopted for desulfurization, and processes of desulfurization by using ionic liquid, active coke and the like are also adopted, and when the active coke desulfurization process is adopted, high-concentration SO after desorption is generally adopted2The smoke gas does not contain the harmful impurities. Therefore, the flue gas in the invention refers to SO-containing flue gas which does not contain toxic and harmful components such as arsenic, Pd, Cd, Cr, fluorine and the like2Flue gas.
(2) High-temperature dust collection: and the flue gas coming out of the reduction reactor enters a high-temperature dust collection working section, and a gas-gas heat exchanger is arranged in the working section to avoid heat loss of the flue gas. And (3) filtering impurities such as coal ash and the like by the smoke through a high-efficiency dust collector to ensure that the smoke is clean, and then entering the conversion sulfur production working section in the step (3). The flue gas from the reduction reactor is cooled to 500-600 ℃ through a gas-gas heat exchanger, then enters a high-temperature dust collector, and the dust content of a flue gas outlet after passing through the high-temperature dust collector is not more than 20mg/Nm3。
(3) A high-temperature conversion sulfur production section: mixing the reducing flue gas which is subjected to high-efficiency dust collection in the step (2) with air or pure oxygen, feeding the mixture into a conversion reactor and reacting to generate sulfur, cooling the sulfur-containing flue gas by a waste heat boiler, recovering redundant heat, and condensing by a condenser to obtain liquid sulfur. The flue gas enters the subsequent low-temperature reduction section (4). The reaction temperature of the conversion reactor is 1000-1200 ℃. Cooling the sulfur-containing flue gas to 250-350 ℃ through a waste heat boiler.
(4) A low-temperature reduction section: heating the cooled flue gas by a reheater, introducing the flue gas into a low-temperature reduction reactor, and removing residual SO in the flue gas2And H2S is converted into sulfur, the sulfur is recovered by a condenser, the tail gas is burnt, and the tail gas is sent to the step (6) for desulfurization; according to different flue gas conditions and requirements of tail gas emission, the tail gas can be subjected to primary low-temperature reduction or secondary low-temperature reduction, and the tail gas is returned to a low-temperature working section for reaction, SO that SO in the tail gas2And H2S is converted into sulfur. The reaction temperature of the low-temperature reduction section is 250-350 ℃.
(5) Degassing and granulating sulfur: degassing the sulfur obtained in the steps (3) and (4), and granulating by using a granulator to obtain a sulfur product;
(6) tail gas desulfurization: and (4) finally, the tail gas in the steps (4) and (5) only needs to be subjected to simple desulfurization, and the emission requirement can be met. If the tail gas desulfurization is carried out by a abandoning method, the total sulfur recovery rate of the system can reach 95-97%, and if the ionic liquid or active coke process is adopted for adsorption and desorption, SO is returned2The recovery rate of sulfur can reach more than 99%.
The following examples are provided to further illustrate the advantageous effects of the present invention.
Example 1
Power plant flue gas active coke desulfurization desorption tail gas
The flue gas of a power plant is mostly desulfurized by limestone gypsum at present, and along with the increasing environmental protection requirement, the power plant gradually adopts other desulfurization processes, such as ionic liquid desulfurization, active coke desulfurization and the like. For high-concentration SO after active coke desulfurization and desorption2The flue gas is also very suitable for being treated by the process route and producing the process sulfur.
The volume fraction of smoke for one example of use is:
the flue gas is characterized by SO2High concentration, low oxygen concentration, 350 ℃ of flue gas temperature and no other harmful impurities, and is suitable for the process route.
(1) Reduction of sulfur dioxide: the flue gas with the composition after the active coke is desulfurized and desorbed directly enters a reduction reactor and is subjected to reduction reaction with coal at 1200 ℃ to generate hydrogen sulfide, COS and CS2Reducing gas is used;
(2) high-temperature dust collection: the temperature of the flue gas from the reduction reactor is reduced to 550 ℃ through a gas-gas heat exchanger, and then the flue gas enters a high-efficiency dust collector to filter impurities such as coal ash and the like, so that the dust content of a flue gas outlet is not more than 20mg/Nm3Ensuring the flue gas to be clean, and then entering a high-temperature conversion sulfur production working section (3);
(3) a high-temperature conversion sulfur production section: mixing the reducing flue gas subjected to high-efficiency dust collection in the step (2) with air, feeding the mixture into a conversion reactor, reacting at 1000 ℃ to generate sulfur, cooling the sulfur-containing flue gas to 280 ℃ through a waste heat boiler, recovering redundant heat, condensing the sulfur-containing flue gas through a condenser to obtain liquid sulfur, and feeding the flue gas into a subsequent low-temperature reduction section (4);
(4) a low-temperature reduction section: heating the cooled flue gas by a reheater at 270 ℃, and then feeding the flue gas into a primary low-temperature reduction reactor at the temperature of 300 ℃; the residual SO in the flue gas2And H2S is converted into sulfur, and after the sulfur is recovered by a condenser, tail gas is burnt.
(5) Degassing and granulating sulfur: degassing the sulfur obtained in the steps (3) and (4), and granulating by using a granulator to obtain a sulfur product;
(6) tail gas desulfurization: adsorption and desorption of SO by using active coke process2The recovery rate of sulfur can reach more than 99%.
Example 2
(1) Reduction of sulfur dioxide: the flue gas after active coke desulfurization and desorption directly enters a reduction reactor to carry out reduction reaction with coal at 1000 ℃ to generate hydrogen sulfide, COS and CS2Reducing gas is used;
(2) high-temperature dust collection: the temperature of the flue gas from the reduction reactor is reduced to 600 ℃ through a gas-gas heat exchanger, and then the flue gas enters a high-efficiency dust collector to filter impurities such as coal ash and the like, so that the dust content of a flue gas outlet is not more than 15mg/Nm3Ensuring the flue gas to be clean, and then entering a high-temperature conversion sulfur production working section (3);
(3) a high-temperature conversion sulfur production section: mixing the reducing flue gas subjected to high-efficiency dust collection in the step (2) with air, feeding the mixture into a conversion reactor, reacting at 1100 ℃ to generate sulfur, cooling the sulfur-containing flue gas to 300 ℃ through a waste heat boiler, recovering redundant heat, condensing through a condenser to obtain liquid sulfur, and feeding the flue gas into a subsequent low-temperature reduction section (4);
(4) a low-temperature reduction section: heating the cooled flue gas by a reheater to 280 ℃, and then feeding the flue gas into a secondary low-temperature reduction reactor at the temperature of 320 ℃; the residual SO in the flue gas2And H2S is converted into sulfur, and after the sulfur is recovered by a condenser, tail gas is burnt.
(5) Degassing and granulating sulfur: degassing the sulfur obtained in the steps (3) and (4), and granulating by using a granulator to obtain a sulfur product;
(6) tail gas desulfurization: adsorption and desorption of SO by using active coke process2The recovery rate of sulfur can reach more than 99%.
Example 3
(1) Reduction of sulfur dioxide: the flue gas with the composition after the active coke is desulfurized and desorbed directly enters a reduction reactor and is subjected to reduction reaction with coal at 1100 ℃ to generate hydrogen sulfide, COS and CS2Reducing gas is used;
(2) high-temperature dust collection: the temperature of the flue gas from the reduction reactor is reduced to 600 ℃ through a gas-gas heat exchanger, and then the flue gas enters a high-efficiency dust collector to filter impurities such as coal ash and the like, so that the dust content of a flue gas outlet is not more than 10mg/Nm3Ensuring the flue gas to be clean, and then entering a high-temperature conversion sulfur production working section (3);
(3) a high-temperature conversion sulfur production section: mixing the reducing flue gas subjected to high-efficiency dust collection in the step (2) with air, feeding the mixture into a conversion reactor, reacting at 1100 ℃ to generate sulfur, cooling the sulfur-containing flue gas to 320 ℃ through a waste heat boiler, recovering redundant heat, condensing the sulfur-containing flue gas through a condenser to obtain liquid sulfur, and feeding the flue gas into a subsequent low-temperature reduction section (4);
(4) a low-temperature reduction section: heating the cooled flue gas by a reheater to 260 ℃, and then feeding the flue gas into a secondary low-temperature reduction reactor at the temperature of 300 ℃; the residual SO in the flue gas2And H2S is converted into sulfur, and after the sulfur is recovered by a condenser, tail gas is burnt.
(5) Degassing and granulating sulfur: degassing the sulfur obtained in the steps (3) and (4), and granulating by using a granulator to obtain a sulfur product;
(6) tail gas desulfurization: adsorption and desorption of SO by using active coke process2The recovery rate of sulfur can reach more than 99%.
By adopting the process route of the invention, the coal source is wide and the cost is low. Compared with the difficult-to-treat complex concentrate smelting flue gas containing a large amount of arsenic, fluoride, heavy metal and other impurities, the invention aims at purer gas, reduces the washing and purification of the flue gas, saves energy, reduces the consumption of coal and finally prepares a qualified sulfur product. Solves the problem of sulfur dioxide pollution and changes the prior SO-containing2The treatment process of flue gas contains SO2Flue gas treatment provides another process route. Through the steps, if the tail gas desulfurization is carried out by a disposal method, the total sulfur recovery rate of the system can reach 95-97%, and if the ionic liquid or active coke process is adopted for adsorption and desorption, SO is returned2The recovery rate of sulfur can reach more than 99%.
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