阅读说明：本技术 一种利用再生铅冶炼烟气直接制备精制硫酸的方法 (Method for directly preparing refined sulfuric acid by using secondary lead smelting flue gas ) 是由 李小兵 卢军胜 李伟伟 卢海军 韩宏磊 王培元 于 2021-10-15 设计创作，主要内容包括：本发明提供一种利用再生铅冶炼烟气直接制备精制用硫酸的方法,所述方法由再生铅冶炼烟气中回收二氧化硫制取精制硫酸,该方法包括以下步骤：烟气净化洗涤；吸附解吸脱硫；配气制酸；硫酸尾气脱硫；烟气除酸雾后排放。其与现有技术相比具有产品质量高,杂质少,直接产出精制硫酸；制酸系统不受冶炼系统周期性操作的波动影响,生产稳定,充分利用再生铅冶炼系统产出的余热,综合运行成本低等优点。(The invention provides a method for directly preparing sulfuric acid for refining by using secondary lead smelting flue gas, which is used for preparing refined sulfuric acid by recovering sulfur dioxide from the secondary lead smelting flue gas and comprises the following steps: purifying and washing flue gas; adsorption, desorption and desulfurization; distributing gas to prepare acid; desulfurizing the sulfuric acid tail gas; and (4) removing acid mist from the flue gas and then discharging. Compared with the prior art, the method has the advantages that the product quality is high, the impurities are few, and the refined sulfuric acid is directly produced; the acid making system is not affected by the fluctuation of the periodic operation of the smelting system, the production is stable, the waste heat produced by the secondary lead smelting system is fully utilized, and the comprehensive operation cost is low.)

1. A method for directly preparing refined sulfuric acid by using secondary lead smelting flue gas is characterized by comprising the following steps:

(1) washing and purifying flue gas: carrying out primary washing by using dynamic wave circulating water, then carrying out secondary washing and cooling by using circulating water of a washing tower, purifying lead smoke dust and other impurities in the smoke, then carrying out electric defogging and dust removal, and then leading out the smoke from the washing tower;

(2) purifying circulating water: the purified sewage after passing through the desalting device is converged into a washing tower, most of washing water in the washing tower is recycled, and a small part of washing water is sent to a sewage treatment device to be treated with sludge;

(3) adsorption, desorption and desulfurization: after washing, cooling and dedusting, the smelted flue gas passes through a reverse spray pipe and is reversely sprayed by a desulfurization rich solution pipeline before entering an absorption tower, SO that the peaks of SO2 are cut and the valleys are filled, rich solution at the bottom of the absorption tower is driven to be stirred, the smelted flue gas enters the absorption tower, SO2 in the flue gas is absorbed by lean solution at low temperature, and the absorbed tail gas is subjected to acid mist removal by an electric demister in the step (6) and then reaches the standard to be discharged; the rich solution absorbing SO2 is fed into a lean rich solution heat exchanger for heat exchange, enters the upper part of a regeneration tower and is heated to be regenerated by a reboiler, the heat source is low-pressure steam by-product of a waste heat boiler matched with the secondary lead smelting, SO2 gas with the concentration of 99 percent is regenerated by a desorption tower, and the balance is water and is used as a raw material for subsequent acid preparation;

(4) and (3) gas distribution and acid preparation: the main process for preparing acid adopts a one-rotation-one-absorption process or a two-rotation-two-absorption process, wherein a converter, a heat exchanger and a flue gas pipeline which are used adopt 304 stainless steel, and a dry absorption tower, a concentrated acid circulating tank and a concentrated acid pipeline adopt steel lining PTFE;

(5) sulfuric acid tail gas desulfurization: the sulfuric acid tail gas after absorption in the step (4) still contains a certain amount of SO2, and further desulfurization treatment is needed;

(6) discharging the flue gas after removing acid mist: and (4) combining the flue gas at the outlet of the absorption tower in the step (3) and the flue gas subjected to sulfuric acid tail gas desulfurization in the step (5), sending the combined flue gas to an electric demister, and further removing acid mist to achieve standard emission.

2. The method for directly preparing refined sulfuric acid by using secondary lead smelting flue gas according to claim 1, which is characterized in that: and (3) performing adsorption desorption desulfurization in the step (2) by adopting ionic liquid desulfurization, organic amine desulfurization or sodium citrate desulfurization.

3. The method for directly preparing refined sulfuric acid by using secondary lead smelting flue gas according to claim 1, which is characterized in that: and (4) preparing air or a mixed gas of pure oxygen and pure nitrogen into the gas preparation acid in the step (4).

4. The method for directly preparing refined sulfuric acid by using secondary lead smelting flue gas according to claim 1, which is characterized in that: the one-to-one suction process in the step (4) comprises the following specific steps: a metering facility of SO2 is arranged in the process system, and the required oxygen is calculated and fed back to the air supplement valve, SO that the amount of the air to be distributed is reasonably controlled; the air is provided with a filter before entering the drying tower so as to remove impurities brought by the air; mixing the filtered air with the desorbed SO2 flue gas, drying the mixture in a drying tower, and feeding the mixture into a converter; the converter is provided with a catalyst section or two catalyst sections or three catalyst sections; and (3) the converted SO3 flue gas enters an absorption tower, a gas filter is arranged in front of the absorption tower, and the SO3 in the flue gas is absorbed by concentrated sulfuric acid to produce sulfuric acid.

5. The method for directly preparing refined sulfuric acid by using secondary lead smelting flue gas according to claim 1, which is characterized in that: one of the desulfurization processes in the step (5) is to directly return to an adsorption desorption desulfurization system for desulfurization treatment; one is adopting hydrogen peroxide solution desulfurization process treatment; and (4) returning the by-product dilute sulfuric acid serving as process replenishing water to the concentrated acid circulation tank in the step (4), and conveying the desulfurized flue gas to the electric demister in the step (6) for further treatment.

6. The method for directly preparing refined sulfuric acid by using secondary lead smelting flue gas according to claim 1, which is characterized in that: the desulfurization process in the step (5) adopts limestone and gypsum process desulfurization, sodium process desulfurization, ammonia process desulfurization and magnesium process desulfurization.

7. The method for directly preparing refined sulfuric acid by using secondary lead smelting flue gas according to claim 1, which is characterized in that: and (5) after further removing the acid mist in the step (6), discharging the acid mist through a chimney after reaching the standard.

Technical Field

The invention belongs to the technical field of secondary lead smelting environment protection, and particularly relates to a method for directly preparing refined sulfuric acid by using secondary lead smelting flue gas.

Background

In recent years, the lead smelting industry in China is rapidly developed, the demand of lead is greatly increased, and the phenomenon of lead ore resource shortage is increasingly serious. The secondary lead industry is vigorously developed and becomes an important component of the sustainable development of the lead industry in China. The refining is one of the main industries of lead consumption, and the raw material source of the secondary lead is mainly the refining of waste lead. With the rapid development of the industries such as automobiles, communication and the like, the refining production and sales volume is continuously increased, and the scrappage volume is sharply increased. In order to fully utilize the lead waste and reduce the pollution of the lead waste to the environment and the waste of resources, a reasonable and scientific recovery mode is adopted to carry out harmless treatment on the lead refining, so that the lead metal enters the virtuous cycle of production-consumption-recycling.

The secondary lead smelting generally comprises several main processes of pretreatment (such as disassembly, crushing, sorting, pre-desulfurization and the like), pyrometallurgical treatment, pollutant treatment and the like of lead-containing metal waste materials such as waste lead refining and the like. The domestic secondary lead factory basically adopts the traditional pyrometallurgical process.

The regenerated lead adopts flue gas containing SO2 generated during pyrometallurgy, and the process scheme for preparing sulfuric acid is mostly adopted at present, and the obtained product sulfuric acid is industrial sulfuric acid. The lead recycling enterprises generally build a recycling factory and a battery factory together, so that lead obtained by recycling lead is used as a main raw material for refining, and the transportation cost is reduced. The quality of the sulfuric acid used in the refining process is higher, and the sulfuric acid needs to meet the requirements of the standard of the superior product in sulfuric acid HG/T2692-2015 for the chemical industry standard storage battery of the people's republic of China, HG/T2692. The acid is prepared from the conventional secondary lead smelting flue gas, and the common industrial sulfuric acid is purified by further post-treatment (such as a distillation method) and can be used as refined acid. This also undoubtedly increases the operating costs of the enterprise.

The existing acid preparation method by using regenerated lead flue gas is based on the characteristic of low SO2 concentration in flue gas, and the industrial sulfuric acid is prepared by adopting an acid preparation process of 'one-rotation absorption and ionic liquid desulfurization'. In conventional production, the produced industrial sulfuric acid is usually distilled by electric heating to prepare sulfuric acid for purification. The process has high power consumption, can produce partial waste acid, has relatively high operation cost, and does not accord with the concept of energy conservation and environmental protection.

The invention patent CN 109675394A discloses a method for preparing full-analysis pure by one-by-one absorption of smelting flue gas with low concentration SO 2. The technology adopts a precision filter to filter the converted flue gas, and finally produces analytically pure sulfuric acid. The content of each impurity in the analytically pure sulfuric acid is far lower than that of the sulfuric acid for refining, and if the analytically pure sulfuric acid is used for refining, the analytically pure sulfuric acid is wasted.

In addition, only low-concentration SO2 smelting flue gas is mentioned in the patent, the applicable SO2 concentration range is not described, and aiming at the characteristics of the secondary lead smelting flue gas (the concentration of SO2 is about 2 percent, and fluctuation exists at the same time), if a one-to-one-absorption process is directly adopted, the conversion self-heating balance is difficult to realize, a large amount of heat supplement is needed, the operation cost is greatly improved, and the method is unreasonable in economy.

The invention patent CN 109028982A discloses a closed circulation system and a desulfurization method for ammonia desulfurization of secondary lead smelting tail gas. The technology does not produce sulfuric acid, but adopts ammonia desulphurization. Although the sulfur resource is recovered, the sulfur resource is not suitable for the product requirements of the secondary lead enterprises.

The invention patent CN 109879255A discloses a system and a method for producing refined sulfuric acid by a pyrite acid making system. The technology mainly optimizes and improves the dry absorption working section of the pyrite acid making system, adopts deionized water to adjust the acid concentration,

reducing impurities brought by water, and blowing the sulfur dioxide dissolved in the deacidification by using an aeration pipe. This is a local effective method and is not an overall process flow suitable for treating the regenerated lead fume.

The invention patent CN 105731394A discloses a refined sulfuric acid preparation device and a preparation method. The technology adopts a fuming acid absorption tower to wash the converted flue gas, removes impurities in the flue gas, enters a flue gas filter for filtering and refining, and finally enters a refined sulfuric acid absorption tower to produce analytically pure refined sulfuric acid. The invention also produces analytically pure sulfuric acid with higher specification, and the operation cost is relatively higher.

Disclosure of Invention

In order to overcome the technical problems, the invention provides a method for directly preparing refined sulfuric acid by using secondary lead smelting flue gas, which comprises the following specific scheme:

a method for directly preparing refined sulfuric acid by using secondary lead smelting flue gas is characterized by comprising the following steps:

(1) washing and purifying flue gas: carrying out primary washing by using dynamic wave circulating water, then carrying out secondary washing and cooling by using circulating water of a washing tower, purifying lead smoke dust and other impurities in the smoke, then carrying out electric defogging and dust removal, and then leading out the smoke from the washing tower;

(2) purifying circulating water: the purified sewage after passing through the desalting device is converged into a washing tower, most of washing water in the washing tower is recycled, and a small part of washing water is sent to a sewage treatment device to be treated with sludge;

(3) adsorption, desorption and desulfurization: after washing, cooling and dedusting, the smelted flue gas passes through a reverse spray pipe and is reversely sprayed by a desulfurization rich solution pipeline before entering an absorption tower, SO that the peaks of SO2 are cut and the valleys are filled, rich solution at the bottom of the absorption tower is driven to be stirred, the smelted flue gas enters the absorption tower, SO2 in the flue gas is absorbed by lean solution at low temperature, and the absorbed tail gas is subjected to acid mist removal by an electric demister in the step (6) and then reaches the standard to be discharged; the rich solution absorbing SO2 is fed into a lean rich solution heat exchanger for heat exchange, enters the upper part of a regeneration tower and is heated to be regenerated by a reboiler, the heat source is low-pressure steam by-product of a waste heat boiler matched with the secondary lead smelting, SO2 gas with the concentration of 99 percent is regenerated by a desorption tower, and the balance is water and is used as a raw material for subsequent acid preparation;

(4) and (3) gas distribution and acid preparation: the main process for preparing acid adopts a one-rotation-one-absorption process or a two-rotation-two-absorption process, wherein a converter, a heat exchanger and a flue gas pipeline which are used adopt 304 stainless steel, and a dry absorption tower, a concentrated acid circulating tank and a concentrated acid pipeline adopt steel lining PTFE;

(5) sulfuric acid tail gas desulfurization: the sulfuric acid tail gas after absorption in the step (4) still contains a certain amount of SO2, and further desulfurization treatment is needed;

(6) discharging the flue gas after removing acid mist: and (4) combining the flue gas at the outlet of the absorption tower in the step (3) and the flue gas subjected to sulfuric acid tail gas desulfurization in the step (5), sending the combined flue gas to an electric demister, and further removing acid mist to achieve standard emission.

Based on the above, the adsorption desorption desulfurization in the step (2) adopts ionic liquid desulfurization, organic amine desulfurization or sodium citrate desulfurization.

Based on the above, the gas preparation acid in the step (4) is prepared by air or a mixed gas of pure oxygen and pure nitrogen.

Based on the above, the one-to-one suction process in the step (4) specifically comprises the following steps: a metering facility of SO2 is arranged in the process system, and the required oxygen is calculated and fed back to the air supplement valve, SO that the amount of the air to be distributed is reasonably controlled; the air is provided with a filter before entering the drying tower so as to remove impurities brought by the air; mixing the filtered air with the desorbed SO2 flue gas, drying the mixture in a drying tower, and feeding the mixture into a converter; the converter is provided with a catalyst section or two catalyst sections or three catalyst sections; and (3) the converted SO3 flue gas enters an absorption tower, a gas filter is arranged in front of the absorption tower, and the SO3 in the flue gas is absorbed by concentrated sulfuric acid to produce sulfuric acid. .

Based on the above, one of the desulfurization processes in the step (5) is to directly return to the adsorption desorption desulfurization system for desulfurization treatment; one is adopting hydrogen peroxide solution desulfurization process treatment; and (4) returning the by-product dilute sulfuric acid serving as process replenishing water to the concentrated acid circulation tank in the step (4), and conveying the desulfurized flue gas to the electric demister in the step (6) for further treatment.

Based on the above, the desulfurization process in the step (5) adopts limestone-gypsum process desulfurization, sodium process desulfurization, ammonia process desulfurization and magnesium process desulfurization.

And (4) after further removing the acid mist in the step (6), performing standard emission through a chimney.

Compared with the prior art, the invention has outstanding substantive characteristics and remarkable progress, and particularly has the following advantages:

(1) the prepared sulfuric acid has high quality and less impurities, and can directly produce finished acid meeting the requirement of refining acid;

(2) the acid making system is not influenced by the fluctuation of the periodic operation of the smelting system, and the production is stable;

(3) the most reasonable sulfur resource recovery scheme of secondary lead production enterprises;

(4) the waste heat produced by the secondary lead smelting system is fully utilized, and the comprehensive operation cost is low.

Detailed Description

The technical solution of the present invention is further described in detail by the following embodiments.

Examples

The invention provides a method for directly preparing refined sulfuric acid by using secondary lead smelting flue gas, which comprises the following steps:

(1) washing and purifying flue gas: firstly, carrying out primary washing on flue gas at the temperature of about 280 ℃ from a secondary lead smelting system by using dynamic wave circulating water, then carrying out secondary washing and cooling by using circulating water of a washing tower, purifying lead flue gas dust and other impurities in the flue gas, then carrying out electric defogging and dust removal on the flue gas, and leading the flue gas out of the washing tower, wherein the temperature of the purified flue gas of the flue gas is controlled to be about 40 ℃;

(2) purifying circulating water: purified sewage generated after purified smelting flue gas passes through the desalting device is converged into a washing tower, most of washing water in the washing tower is recycled, and a small part of water is sent to a sewage treatment device to be treated with sludge;

(3) adsorption, desorption and desulfurization: after washing, cooling and dedusting, the smelted flue gas passes through a reverse spray pipe and is reversely sprayed by a desulfurization rich solution pipeline before entering an absorption tower, SO that the peaks of SO2 are cut and the valleys are filled, rich solution at the bottom of the absorption tower is driven to be stirred, the smelted flue gas enters the absorption tower, SO2 in the flue gas is absorbed by lean solution at low temperature, and the absorbed tail gas is subjected to acid mist removal by an electric demister in the step (6) and then reaches the standard to be discharged; the rich solution absorbing SO2 is fed into a lean rich solution heat exchanger for heat exchange, enters the upper part of a regeneration tower and is heated to be regenerated by a reboiler, the heat source is low-pressure steam by-product of a waste heat boiler matched with the secondary lead smelting, SO2 gas with the concentration of 99 percent is regenerated by a desorption tower, and the balance is water and is used as a raw material for subsequent acid preparation;

(4) and (3) gas distribution and acid preparation: the main process for preparing acid adopts a one-rotation-one-absorption process or a two-rotation-two-absorption process, wherein a converter, a heat exchanger and a flue gas pipeline which are used adopt 304 stainless steel, and a dry absorption tower, a concentrated acid circulating tank and a concentrated acid pipeline adopt steel lining PTFE;

(5) sulfuric acid tail gas desulfurization: the sulfuric acid tail gas after absorption in the step (4) still contains a certain amount of SO2, and further desulfurization treatment is needed;

(6) discharging the flue gas after removing acid mist: and (4) combining the flue gas at the outlet of the absorption tower in the step (3) and the flue gas subjected to sulfuric acid tail gas desulfurization in the step (5), sending the combined flue gas to an electric demister, and further removing acid mist to achieve standard emission.

And (3) performing adsorption desorption desulfurization in the step (2) by adopting ionic liquid desulfurization, organic amine desulfurization or sodium citrate desulfurization.

And (4) preparing air or a mixed gas of pure oxygen and pure nitrogen into the gas preparation acid in the step (4).

The one-to-one suction process in the step (4) comprises the following specific steps: a metering facility of SO2 is arranged in the process system, and the required oxygen is calculated and fed back to the air supplement valve, SO that the amount of the air to be distributed is reasonably controlled; the air is provided with a filter before entering the drying tower so as to remove impurities brought by the air; mixing the filtered air with the desorbed SO2 flue gas, drying the mixture in a drying tower, and feeding the mixture into a converter; the converter is provided with a catalyst section or two catalyst sections or three catalyst sections; and (3) the converted SO3 flue gas enters an absorption tower, a gas filter is arranged in front of the absorption tower, and the SO3 in the flue gas is absorbed by concentrated sulfuric acid to produce sulfuric acid. .

One of the desulfurization processes in the step (5) is to directly return to an adsorption desorption desulfurization system for desulfurization treatment; one is adopting hydrogen peroxide solution desulfurization process treatment; and (4) returning the by-product dilute sulfuric acid serving as process replenishing water to the concentrated acid circulation tank in the step (4), and conveying the desulfurized flue gas to the electric demister in the step (6) for further treatment.

The desulfurization process in the step (5) adopts limestone and gypsum process desulfurization, sodium process desulfurization, ammonia process desulfurization and magnesium process desulfurization.

And (5) after further removing the acid mist in the step (6), discharging the acid mist through a chimney after reaching the standard.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention and not to limit it; although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art will understand that: modifications to the specific embodiments of the invention or equivalent substitutions for parts of the technical features may be made; without departing from the spirit of the present invention, it is intended to cover all aspects of the invention as defined by the appended claims.