阅读说明：本技术 一种用于废硫酸的浓缩方法 (Concentration method for waste sulfuric acid ) 是由 黄中桂 袁晓林 朱礼华 陈军 孔德明 于 2020-07-28 设计创作，主要内容包括：本发明涉及一种用于废硫酸的浓缩方法,基于一套浓缩装置,包括有换热式过滤釜、卧式换热器、涂布式结晶釜、循环精馏塔和换热式膜浓缩釜,所述涂布式结晶釜、循环精馏塔和换热式膜浓缩釜上均连接有双重冷凝器；浓缩方法包括有：1).过滤；2).加热；3).结晶；4).精馏；5).浓缩；本发明的废硫酸的浓缩方法采用两个循环：换热-过滤-结晶循环,将废硫酸中的各种盐类含量降低,完全过滤不溶杂质；结晶-精馏循环,将溶液中的盐类含量降至最低,精馏出废硫酸溶液中的各种有机物杂质,最终得到高纯度、高浓度的硫酸溶液；便于硫酸的再次套用,可显著提高硫酸的利用效率,降低生产成本而提高经济效益,符合企业的利益,满足市场的需求。(The invention relates to a concentration method for waste sulfuric acid, which is based on a set of concentration device and comprises a heat exchange type filtering kettle, a horizontal heat exchanger, a coating type crystallization kettle, a circulating rectification tower and a heat exchange type membrane concentration kettle, wherein double condensers are connected to the coating type crystallization kettle, the circulating rectification tower and the heat exchange type membrane concentration kettle; the concentration method comprises the following steps: 1) filtering; 2) heating; 3) crystallizing; 4) rectifying; 5) concentrating; the concentration method of the waste sulfuric acid adopts two cycles: heat exchange-filtration-crystallization circulation is carried out, the content of various salts in the waste sulfuric acid is reduced, and insoluble impurities are completely filtered; crystallization-rectification circulation, namely, reducing the salt content in the solution to the minimum, rectifying various organic impurities in the waste sulfuric acid solution to finally obtain a high-purity and high-concentration sulfuric acid solution; the method is convenient for reuse of the sulfuric acid, can obviously improve the utilization efficiency of the sulfuric acid, reduces the production cost to improve the economic benefit, accords with the benefits of enterprises, and meets the market demand.)

1. A method for concentrating waste sulfuric acid, which is characterized in that: the concentration method is based on a set of concentration device, the concentration device comprises a heat exchange type filtering kettle (1), a horizontal heat exchanger (2), a coating type crystallization kettle (3), a circulating rectification tower (4) and a heat exchange type membrane concentration kettle (5), and double condensers (6) are connected to the coating type crystallization kettle (3), the circulating rectification tower (4) and the heat exchange type membrane concentration kettle (5);

the method for concentrating the waste sulfuric acid comprises the following steps:

1) filtering: firstly, introducing waste sulfuric acid into a heat exchange type filtering kettle (1), controlling the filtering pressure in the kettle to be 0.15-0.55 Mpa, introducing a refrigerant into the heat exchange type filtering kettle (1) to control the temperature in filtering to be 0-15 ℃, wherein the higher the concentration of the waste sulfuric acid solution is, the lower the temperature in the kettle is;

2) heating: conveying the filtered solution into a horizontal heat exchanger (2), performing heat exchange with a heating medium, controlling the temperature of the waste sulfuric acid solution to be 90-100 ℃, and preheating the waste sulfuric acid solution;

3) crystallization: conveying the preheated waste sulfuric acid solution into a coating type crystallization kettle (3), slowly vacuumizing the coating type crystallization kettle (3), controlling the temperature in the kettle to be 100-150 ℃ to prevent bumping, controlling the ratio of the outflow volume to the inflow volume of the kettle bottom solution to be 1: 3-5, and condensing the top steam by using a double condenser (6);

transferring the crystallized solution into a heat exchange type filtering kettle (1) again for fine filtering until no crystal is generated, and transferring the solution into a circulating rectifying tower (4);

4) rectifying: controlling the temperature of the bottom of the circulating rectifying tower (4) to be 200-300 ℃, condensing distilled steam by using a double condenser (6), and controlling the reflux ratio to be 2-3; the rectified tower bottom solution is transferred into a coating type crystallization kettle (3) again for crystallization treatment until no steam flows out from the top of the circulating rectification tower (4), and the tower bottom solution is conveyed to a heat exchange type membrane concentration kettle (5);

5) concentrating: the ceramic nanofiltration permeable membrane is filled in the heat exchange type membrane concentration kettle (5), the temperature of the heat exchange type membrane concentration kettle (5) is controlled not to exceed 60 ℃, and the sulfuric acid solution is concentrated to obtain the high-concentration sulfuric acid solution.

2. The method for concentrating spent sulfuric acid according to claim 1, wherein: the heat exchange type filtering kettle (1) comprises double layers of active carbon filtering layers (7) and a molecular sieve filtering layer (8) clamped between the active carbon filtering layers (7).

3. The method for concentrating spent sulfuric acid according to claim 1, wherein: two ends of the coating type crystallization kettle (3) are provided with crystallization filtering layers (9), and the crystallization filtering layers (9) and the molecular sieve filtering layers (8) are made of the same material.

4. The method for concentrating spent sulfuric acid according to claim 1, wherein: the coating crystallizer (10) is stacked in multiple layers and is arranged in the coating crystallization kettle (3), and a plurality of liquid leakage holes (12) for liquid leakage are formed in the coating crystallizer (10).

5. The method for concentrating spent sulfuric acid according to claim 1, wherein: the mass transfer packing (11) is filled in the circulating rectification tower (4), and the mass transfer packing (11) is a mixture of at least 2 different packing.

6. The method for concentrating spent sulfuric acid according to claim 1, wherein: the heat exchange type filtering kettle (1), the horizontal heat exchanger (2) and the coating type crystallization kettle (3) form a heat exchange-filtering-crystallization cycle.

7. The method for concentrating spent sulfuric acid according to claim 1, wherein: the coating type crystallization kettle (3) and the circulating rectifying tower (4) form a crystallization-rectification cycle.

Technical Field

The invention relates to the technical field of waste acid concentration, in particular to a concentration method for waste sulfuric acid.

Background

Sulfuric acid has been widely used as a chemical product in various industries, such as chemical industry, petroleum industry, etc., and a large amount of dilute sulfuric acid is produced in the production process. In order to avoid pollution of dilute sulfuric acid to the environment, lime or other alkaline solutions are generally adopted for neutralization, but consumption of lime or other alkaline solutions is caused, and waste of sulfuric acid resources is caused, and concentration of waste sulfuric acid is beneficial to reducing consumption of substances such as lime and the like, recycling of sulfuric acid can be achieved, economic cost is increased, and a resource-saving society is constructed.

At present, the concentration treatment of dilute sulfuric acid in production mainly comprises the following methods: evaporating and eluting water at high temperature in a heating environment, or concentrating under reduced pressure in a heating process. However, since sulfuric acid has a strong corrosiveness, it is liable to corrode the concentration equipment, and the consumption rate of the concentration equipment is further increased under a high temperature condition, which will increase the maintenance and management costs of the concentration equipment. In addition, different industrial waste liquids contain dilute sulfuric acid to be recovered, and also contain other waste materials, for example, in the process of producing alkylate by a sulfuric acid method, isoparaffin and olefin generate alkylate under the catalysis of strong acid, and the reaction only contains waste sulfuric acid in the waste liquid, but also contains a small amount of unreacted isoparaffin, olefin and alkylate which is completely separated. The waste sulfuric acid solution from the pickling of the factory may also contain metal ions such as Fe 3+, Ni +, Cr 3+ and the like, and may also contain chlorine or other suspended matters. If the waste liquid is directly used for heating and concentrating, only the effect of concentrating sulfuric acid can be achieved, and the effect of increasing the purity of the sulfuric acid cannot be achieved.

In conclusion, the prior art has the problems that the equipment loss rate is high and the purity of the sulfuric acid cannot be improved in the process of heating and concentrating the sulfuric acid.

Disclosure of Invention

The invention aims to provide a method for concentrating waste sulfuric acid, which aims to recover a high-purity and high-concentration sulfuric acid solution from the waste sulfuric acid, degrade the loss rate, improve the economic benefit and avoid environmental pollution.

The invention is realized by the following technical scheme:

a concentration method for waste sulfuric acid is based on a set of concentration device, the concentration device comprises a heat exchange type filtering kettle, a horizontal heat exchanger, a coating type crystallization kettle, a circulating rectification tower and a heat exchange type membrane concentration kettle, and double condensers are connected to the coating type crystallization kettle, the circulating rectification tower and the heat exchange type membrane concentration kettle;

the method for concentrating the waste sulfuric acid comprises the following steps:

1) filtering: firstly, introducing waste sulfuric acid into a heat exchange type filtering kettle, controlling the filtering pressure in the kettle to be 0.15-0.55 Mpa, introducing a refrigerant into the heat exchange type filtering kettle, controlling the temperature during filtering to be 0-15 ℃, wherein the higher the concentration of a waste sulfuric acid solution is, the lower the temperature in the kettle is;

2) heating: conveying the filtered solution into a horizontal heat exchanger, performing heat exchange with a heating medium, controlling the temperature of the waste sulfuric acid solution to be 90-100 ℃, and preheating the waste sulfuric acid solution;

3) crystallization: conveying the preheated waste sulfuric acid solution into a coating type crystallization kettle, slowly vacuumizing the coating type crystallization kettle, controlling the temperature in the kettle to be 100-150 ℃ to prevent bumping, controlling the ratio of the outflow volume to the inflow volume of the solution at the bottom of the kettle to be 1: 3-5, and condensing the steam at the top by using a double condenser;

transferring the crystallized solution into a heat exchange type filtering kettle again for fine filtering until no crystal is generated, and transferring the solution into a circulating rectifying tower;

4) rectifying: controlling the temperature of the bottom of the circulating rectifying tower to be 200-300 ℃, condensing distilled steam by using a double condenser, and controlling the reflux ratio to be 2-3; transferring the rectified tower bottom solution into a coating crystallization kettle again for crystallization treatment until no steam flows out from the top of the circulating rectification tower, and conveying the tower bottom solution to a heat exchange type membrane concentration kettle;

5) concentrating: and a ceramic nanofiltration permeable membrane is filled in the heat exchange type membrane concentration kettle, the temperature of the heat exchange type membrane concentration kettle is controlled not to exceed 60 ℃, and the sulfuric acid solution is concentrated to obtain a high-concentration sulfuric acid solution.

As a preferable technical scheme, the heat exchange type filtering kettle comprises double-layer active carbon filtering layers and a molecular sieve filtering layer clamped between the active carbon filtering layers.

As a preferred technical scheme, two ends of the coating type crystallization kettle are provided with crystallization filtering layers, and the crystallization filtering layers and the molecular sieve filtering layers are made of the same material.

As a preferable technical scheme, a coating crystallizer with multiple layers stacked is arranged in the coating crystallization kettle, and a plurality of liquid leakage holes for liquid leakage are formed in the coating crystallizer.

As a preferred technical scheme, mass transfer fillers are filled in the circulating rectification tower, and the mass transfer fillers are a mixture of at least 2 different fillers.

As a preferred technical scheme, the heat exchange type filtering kettle, the horizontal heat exchanger and the coating type crystallization kettle form a heat exchange-filtering-crystallization cycle.

As a preferred technical scheme, the coating type crystallization kettle and the circulating rectifying tower form a crystallization-rectification cycle.

The invention has the beneficial effects that: the concentration method of the waste sulfuric acid adopts two cycles: a heat exchange-filtration-crystallization cycle to reduce the content of various salts in the waste sulfuric acid, completely filter insoluble impurities, and further concentrate the concentration of the sulfuric acid solution; the crystallization-rectification cycle is used for reducing the salt content in the solution to the minimum, rectifying various organic impurities in the waste sulfuric acid solution, further improving the purity of the sulfuric acid solution, reducing the impurity content in the sulfuric acid solution, finally obtaining the sulfuric acid solution with high purity and high concentration, facilitating the reuse of sulfuric acid, remarkably improving the utilization efficiency of sulfuric acid, reducing the production cost, improving the economic benefit, meeting the benefits of enterprises and meeting the market demands.

Drawings

FIG. 1 is a schematic view of the overall configuration of a concentration apparatus for waste sulfuric acid according to the present invention.

FIG. 2 is a schematic view showing the structure of a weep hole of the concentrating apparatus for waste sulfuric acid of the present invention.

In the figure: 1. a heat exchange type filtering kettle; 2. a horizontal heat exchanger; 3. a coating type crystallization kettle; 4. a circulating rectifying tower; 5. a heat exchange type membrane concentration kettle; 6. a double condenser; 7. an activated carbon filter layer; 8. a molecular sieve filtration layer; 9. a crystallization filtration layer; 10. coating a crystallizer; 11. mass transfer packing; 12. and (4) a liquid leakage hole.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.