LPG hydrogen sulfide and thiol removal process and additives

For the desulfurization of liquefied gas, we use the MDEA amine solution method. If the H2S content remains high after desulfurization, it is recommended to re-evaluate whether the load on your facility and the amount of amine used are sufficient； For the desulfurization of liquefied gas, fiber membrane desulfurization technology is widely used at present; it requires less space, has lower alkali consumption, and yields good results. Our existing plants still use the liquid-liquid method, while new plants are planned to adopt fiber membrane technology.

The hypergravity complexed iron desulfurization method we use works quite well.

The latest technologies can reduce the total sulfur content in pure coker liquefied gas to below 50 mg/Nm3; feel free to ask me if you have any questions

Summary of the Application of a New Process for Dry Desulfurization and Deodorization of Naphtha and Solvent Oils Zhang Xianmao, Li Xingjian, Zhao Zhijie, Wang Guoxing (Wuhan Colin Fine Chemicals Co., Ltd., Wuhan 430223) 1 Introduction The sulfides contained in solvent oils and naphtha mainly include hydrogen sulfide, elemental sulfur, thiols, thiophenes, etc. Among these, hydrogen sulfide, elemental sulfur, and thiols are active forms of sulfur; they cause severe corrosion to pipelines and equipment and have an extremely strong unpleasant odor, thereby having a significant impact on product quality and equipment safety. Traditional desulfurization processes include hydrogenation, alkaline extraction, and alkali-free deodorization. The hydrogenation process requires high temperature and pressure, involves large equipment investment, and has high operating costs ； Alkali extraction has a low desulfurization accuracy, and it generates large amounts of alkali slag, leading to secondary pollution. Alkali-free deodorization is effective in removing small molecular thiols, but it is difficult to remove large molecular thiols. In light of the above circumstances, Wuhan Colin Fine Chemical Co., Ltd. developed a new dry-process desulfurization and deodorization technique. Since its successful development in 2002, this technique has been successfully applied in dozens of solvent oil and naphtha deodorization units across China. 2 Process Principle: This process utilizes a W702 composite oxide desulfurization agent in combination with a W201 thiol conversion catalyst. The W702 desulfurization agent is used to remove corrosive sulfides such as H2S and elemental sulfur, ensuring that the H2S concentration remains below 0.1 ppm, thereby allowing proper corrosion resistance of copper sheets. The W201 thiol conversion catalyst is used to convert thiolic sulfur in oils into dialkyl disulfides, thereby ensuring that the level of thiolic sulfur remains below 10PPM, satisfying the Drayton test requirements; moreover, the oils after desulfurization have no noticeable odor. 3 Industrial Applications 3.1 Application in Naphtha Desulfurization and Deodorization Processes The first phase of the renovation project for the 1.2 million-ton atmospheric distillation unit at Daqing Branch of Lanxing Petroleum Co., Ltd. was completed and put into operation in October 2006. The naphtha production capacity is 48,000 tons per year, with a total sulfur content of ≤150 ppm and hydrogen sulfide content of ≤100 ppm. The desulfurization unit utilizes a new dry desulfurization and deodorization process developed by Wuhan Collin Fine Chemicals Co., Ltd.; 14 m3 of W702 desulfurization agent and 8 m3 of W201 thiol conversion catalyst are used in this system. After the removal of corrosive sulfides such as H2S and elemental sulfur using the W702 desulfurizer, the H2S content is less than 0.1 ppm, and the corrosion of copper sheets is at most grade 1. After the thiol conversion catalyst W201 was used to convert the thiolic sulfur in the oil into dialkyl disulfides, the thiol content was reduced to less than 4 ppm; the Drayton test passed successfully, and the quality of the naphtha met the standards specified in Q/SY26-2002. Maoming Huayue Group Company uses the vacuum distillation naphtha supplied by Sinopec Maoming Branch as raw material to produce solvent oils. However, due to the high levels of hydrogen sulfide and thiols in the naphtha, equipment corrosion is severe, the products have a strong odor, and issues such as copper sheet corrosion and failure to meet the requirements of the Drabinsky test occur, which has a significant impact on the company’s safe production and product sales. As a result of extensive research, the company adopted a new dry desulfurization and deodorization process that utilizes the W702 composite oxide desulfurizer developed by Wuhan Kolin Fine Chemicals Co., Ltd., in combination with the W201 thiol conversion catalyst. The plant is designed with a processing capacity of 100,000 tons per year. The loading volume of the W702 composite oxide desulfurization agent is 7 m3, while that of the W201 thiol conversion catalyst is 13 m3. It was completed in December 2004 and put into operation in February 2005, achieving successful commissioning from the first attempt. The hydrogen sulfide level at the naphtha inlet was 20–40 ppm, and the thiol level was 80–100 ppm; copper sheet corrosion reached level 4 or higher. After treatment by the desulfurization unit, the hydrogen sulfide level dropped to less than 0.1 ppm, the thiol level to less than 5 ppm, and copper sheet corrosion was reduced to level 1. The Drabek test was passed, and both the stability and odor of the product were significantly improved. However, after the unit had been in operation for over 20 days, signs of an increase in the thiol sulfur content began to appear. Wuhan Collin Company promptly sent technical personnel to the site to investigate the cause. It was found that the original design specified that the H2S level in the naphtha should be below 50 ppm, and the thiol level below 100 ppm. But due to the use of high-sulfur crude oil by the original petrochemical plant, the actual sulfur content in the naphtha was on the high side, with the thiol content exceeding 300 ppm. After implementing oxygen supplementation measures, the system operated stably, and the desulfurization effect was satisfactory, meeting the requirements of the desulfurization design. This approach played an important role in improving the quality of the oil and reducing its odor. 3.2 Applications in the desulfurization and deodorization of light hydrocarbons: The Qingsheng Chemical Plant in Daqing is designed to process 80,000 tons of light hydrocarbons per year, which are used to produce solvent oils such as 30#, 6#, 120#, and 200#. Due to the presence of sulfides such as H2S and RSH in light hydrocarbons, solvent oils have a strong odor, and copper sheets suffer from unacceptable corrosion. In 2002, the plant adopted the dry desulfurization and deodorization process developed by Wuhan Colin Fine Chemicals Co., Ltd. First, the W702 composite oxide desulfurization agent was used to remove H2S from the light hydrocarbons, and then the W201 thiol conversion catalyst was employed to convert RSH in those hydrocarbons into dialkyl disulfides, thereby achieving desulfurization and deodorization. This device was put into use in August 2002. The W702 composite oxide desulfurization agent has a H2S removal capacity of >20%, and a high desulfurization accuracy