Method for purifying chemical byproduct hydrogen sulfide gas

Abstract

The invention belongs to the field of chemical industry purification processes, and particularly relates to a method for purifying a chemical industry byproduct hydrogen sulfide gas. The method comprises the following steps: pretreating hydrogen sulfide gas at 0-60 DEG C under unlimited pressure, and separating small liquid drops in the hydrogen sulfide gas through a mist capturing or gas-liquid separator; then adopting a polar adsorption section, a medium polar adsorption section and a non-polar adsorption section, and successively separating organic matter components in the hydrogen sulfide gas under the filtering conditions that the temperature is-20 to 45 DEG C, the pressure is 0.01 to 5.0 MPa and the flow rate is 1 to 1,000 BV / h, so as to obtain the filtered gas, namely a final product. According to the process, small liquid drops in the hydrogen sulfide gas are separated, and organic impurities in the hydrogen sulfide gas are effectively separated after adsorption of the one-stage or multi-stage macroporous adsorption resin, so that the quality of hydrogen sulfide is improved, and the quality of subsequent products such as sulfur or sulfuric acid for industrial reproduction of hydrogen sulfide is also improved.

Description

Technical Field

[0001] The present invention belongs to the field of purification processes for chemical products, and particularly relates to a method for purifying hydrogen sulfide gas as a by-product of the chemical industry. Background Art

[0002] The recycled hydrogen sulfide gas from chemical plants contains a large amount of impurities such as organic substances, which increases the burden on subsequent devices such as acid production and Claus sulfur recovery. The types of organic substances in the gas are complex, and it is difficult to purify them through traditional processes such as pressure swing adsorption and activated carbon adsorption. The hydrogen sulfide gas without separating this part of organic substances results in more impurities in subsequent products such as sulfuric acid or sulfur.

[0003] The recycled hydrogen sulfide gas in industry contains a large amount of impurities. Hydrogen sulfide is mainly converted into sulfuric acid or sulfur through combustion. The impurity gases during the combustion process can cause the sulfuric acid or sulfur products to turn yellow or black due to incomplete combustion, etc. The burner will also have increased difficulty in temperature control due to the relatively high calorific value of the impurity gases. And the device frequently gets blocked, seriously affecting the production efficiency and equipment life, increasing the production cost and maintenance difficulty. Currently, there is a lack of effective purification methods and systems for such acid gases to solve these problems. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for purifying hydrogen sulfide gas as a by-product of the chemical industry, which can separate the organic substances in the hydrogen sulfide gas. The quality of sulfur or sulfuric acid produced after purifying the hydrogen sulfide will be greatly improved, and the phenomenon of the sulfur or sulfuric acid products turning black will no longer occur, thereby improving the quality of the subsequent products of the recycled hydrogen sulfide in industry.

[0005] The main impurities in the recycled hydrogen sulfide in industry that affect subsequent deep processing are mainly organic substances. The core of this technical solution is to utilize the principle of selective adsorption of organic substances by macroporous adsorption resins, and through constructing a suitable process flow, separate the organic substances in the hydrogen sulfide step by step, ultimately achieving the purpose of purifying the hydrogen sulfide gas.

[0006] To meet the preconditions for the adsorption of macroporous adsorption resins, the raw material hydrogen sulfide gas needs to be pretreated to separate liquid components such as oil droplets and water droplets in the gas: The adsorption of macroporous adsorption resins is divided into three adsorption sections of polar, medium polar, and non-polar, and the organic substance components in the hydrogen sulfide gas are separated successively.

[0007] The specific implementation scheme of the present invention is as follows: (1) Pretreat the hydrogen sulfide gas after the vacuum unit: at a temperature of 0 - 60 °C, with an unlimited pressure, and separate the small liquid droplets in the hydrogen sulfide gas through a mist catcher or a gas-liquid separator; (2)The hydrogen sulfide gas after separating small droplets is introduced into the first-stage non-polar resin adsorption tank. The filtration temperature is strictly controlled at -20 - 45°C, the pressure at 0.01 MPa - 5.0 MPa, and the flow rate at 1 - 1000 BV / h. After the gas is preliminarily purified, it enters the second-stage adsorption tank; (3)The gas purified by the first-stage non-polar resin adsorption tank enters the second-stage medium-polar resin adsorption tank. When the gas enters the second-stage medium-polar resin adsorption tank, the above temperature, pressure, and flow rate conditions are still maintained. The further purified gas enters the third-stage adsorption tank.

[0008] (4)The gas purified by the second-stage medium-polar resin adsorption tank enters the third-stage polar resin adsorption tank. The specific filtration conditions are still a temperature of -20 - 45°C, a pressure of 0.01 MPa - 5.0 MPa, and a flow rate of 1 - 1000 BV / h. The filtered gas is the final product.

[0009] (5)After the adsorption tank is saturated, it is desorbed with circulating nitrogen at 150°C. After desorption is completed, the adsorption tank is cooled, and the cooled adsorption tank can be put into circulation again.

[0010] The above non-polar resin has a styrene-divinylbenzene (Styrene-DVB) copolymer as the backbone and does not contain polar groups. The representative models of non-polar resins are: HPD100, XAD-2, D101.

[0011] The above medium-polar resin has a chemical structure with weak polar groups such as ester groups and ketone groups introduced into the styrene backbone. The representative models of medium-polar resins are: AB-8, XAD-7, HPD300.

[0012] The above polar resin has a chemical structure containing strong polar groups such as hydroxyl groups, amino groups, and amide groups.

[0013] The representative models of polar resins are: D-4020, S-8, XAD-1180.

[0014] Non-polar resins adsorb non-polar or weakly polar substances (such as hydrophobic molecules) through van der Waals forces and can adsorb flavonoids, terpenoids, and lipophilic components.

[0015] The medium-polar resin is characterized by both hydrophobic and hydrophilic effects and is suitable for medium-polar substances, for the separation of alkaloids, saponins, and phenolic acid compounds.

[0016] Polar resins adsorb polar substances (such as water-soluble components) through hydrogen bonds or dipole interactions and are mainly for the purification of sugars, polyphenols, and amino acids.

[0017] The present invention has the following advantages compared with the existing technologies: Through this process, the small droplets in hydrogen sulfide gas are separated, and after adsorption by one or more macroporous adsorption resins, the organic impurities in hydrogen sulfide gas are effectively separated, improving the quality of hydrogen sulfide and also enhancing the quality of subsequent products such as sulfur or sulfuric acid in industrial hydrogen sulfide recovery. Specific Embodiments

[0018] The technical solutions and their effects of the present invention are further described below through specific examples. Examples

[0019] Taking the acid gas pretreatment of the vacuum potassium carbonate desulfurization device in a coking plant as an example, the acid gas recovered from the regeneration tower contains a large amount of organic substances such as benzene, toluene, naphthalene, and cycloalkanes, resulting in unstable combustion in the Claus furnace and frequent problems such as blockage in the device. Now, the purification system is connected after the acid gas vacuum unit. After being purified by the purification device, the acid gas then enters the Claus sulfur recovery section, which can effectively solve the above problems.

[0020] The specific implementation method is as follows: (1) Pretreat the hydrogen sulfide gas after the vacuum unit: at a temperature of 0 - 60°C and any pressure. Separate the small droplets in the hydrogen sulfide gas through a mist eliminator or a gas-liquid separator.

[0021] (2) Pass the hydrogen sulfide gas after separating the small droplets into the first-stage non-polar resin adsorption tank. Strictly control the filtration temperature at -20 - 45°C, the pressure at 0.01 MPa - 5.0 MPa, and the flow rate at 1 - 1000 BV / h. After the gas is preliminarily purified, it enters the second-stage adsorption tank.

[0022] (3) The gas purified by the first-stage non-polar resin adsorption tank enters the second-stage medium-polar resin adsorption tank. When the gas enters the second-stage medium-polar resin adsorption tank, still maintain the above temperature, pressure, and flow rate conditions. The further purified gas enters the third-stage adsorption tank.

[0023] (4) The gas purified by the second-stage medium-polar resin adsorption tank enters the third-stage polar resin adsorption tank. The specific filtration conditions are still a temperature of -20 - 45°C, a pressure of 0.01 MPa - 5.0 MPa, and a flow rate of 1 - 1000 BV / h. The filtered gas is the final product.

[0024] (5) After the adsorption tank is saturated, use circulating nitrogen at 150°C to desorb the adsorption tank. After desorption is completed, cool the adsorption tank, and the cooled adsorption tank can be put into circulation again.

[0025] The above non-polar resin has a styrene-divinylbenzene (Styrene-DVB) copolymer as its backbone, contains no polar groups, and adsorbs non-polar or weakly polar substances (such as hydrophobic molecules) through van der Waals forces. It can adsorb flavonoids, terpenoids, and lipophilic components. The representative resin models are: HPD100, XAD-2, D101.

[0026] The above medium-polar resin has a chemical structure with weakly polar groups such as ester groups and ketone groups introduced into the styrene backbone. Its characteristic is that it has both hydrophobic and hydrophilic effects, is suitable for medium-polar substances, and is used for the separation of alkaloids, saponins, and phenolic acid compounds. The representative resin models are AB-8, XAD-7, HPD300.

[0027] The above polar resin has a chemical structure containing strong polar groups (such as hydroxyl groups, amino groups, amide groups), adsorbs polar substances (such as water-soluble components) through hydrogen bonding or dipole interaction, and is mainly used for the purification of sugars, polyphenols, and amino acids. The representative resin models are: D-4020, S-8, XAD-1180.

Claims

1. A method for purifying hydrogen sulfide gas as a chemical by-product, characterized in that The specific method is as follows: (1)Pretreat the hydrogen sulfide gas after the vacuum unit: at a temperature of 0 - 60 °C, with no limit on pressure, and separate the small liquid droplets in the hydrogen sulfide gas through a mist catcher or a gas-liquid separator; (2)Pass the hydrogen sulfide gas after separating the small liquid droplets into the first-stage non-polar resin adsorption tank, strictly control the filtration temperature at -20 - 45 °C, the pressure at 0.01 MPa – 5.0 MPa, and the flow rate at 1 - 1000 BV / h, so that the gas is preliminarily purified and then enters the second-stage adsorption tank; (3)The gas purified by the first-stage non-polar resin adsorption tank enters the second-stage medium-polar resin adsorption tank. When the gas enters the second-stage medium-polar resin adsorption tank, still maintain the above temperature, pressure and flow rate conditions, and the further purified gas enters the third-stage adsorption tank; (4)The gas purified by the second-stage medium-polar resin adsorption tank enters the third-stage polar resin adsorption tank. The specific filtration conditions are still a temperature of -20 - 45 °C, a pressure of 0.01 MPa - 5.0 MPa, and a flow rate of 1 - 1000 BV / h. The filtered gas is the final product; (5)After the adsorption tank is saturated, use circulating nitrogen at 150 °C to desorb the adsorption tank. After the desorption is completed, cool the adsorption tank, and the cooled adsorption tank can be put into circulation again.

2. The method for purifying hydrogen sulfide gas as a chemical by-product according to claim 1, characterized in that The non-polar resin mentioned above has a styrene-divinylbenzene (Styrene-DVB) copolymer as the backbone and does not contain polar groups. The representative models of the non-polar resin are: HPD100, XAD-2, D101.

3. A method for purifying hydrogen sulfide gas as a chemical by-product according to claim 1, characterized in that The medium-polar resin mentioned above has a chemical structure with weak polar groups such as ester groups and ketone groups introduced into the styrene backbone. The representative models of the resin are AB-8, XAD-7, HPD300.

4. A method for purifying hydrogen sulfide gas as a chemical by-product according to claim 1, characterized in that The polar resin mentioned above has a chemical structure containing strong polar groups such as hydroxyl groups, amino groups, and amide groups. The representative models of the resin are: D-4020, S-8, XAD-1180.