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1059276 
Journal Article 
Factors Affecting Decomposition of Sulfolane Solvent in Aromatic Extraction Units and Countermeasures 
Li, D; Li, H; Liu, D 
2011 
1 
Zhongwai Nengyuan
ISSN: 1673-579X 
16 
2 
95-99 
Chinese 
Sulfolane (C(4)H(8)SO(2)) is a colorless, water-soluble, high -polarity chemical product with good thermal stability. Its toxicity is very low, density is relatively high, specific heat is low and boiling point is high. The two aromatic extraction units in the Chemical Plant No. 1 of Daqing Petrochemical Company both use UOP's production technology. Using sulfolane solvent as the extraction agent, the units extract the benzene, methylben-zene and dimethylbenzene in hydrogenated gasoline and rectify them to obtain high purity of benzene, methyl-benzene and dimethylbenzene. In routine production, when the temperature is lower than 220 degree C, sulfolane solvent decomposes at a low speed, while when the temperature exceeds 220 degree C, as the temperature rises, its decomposition speed rises sharply. High temperature will facilitate the decomposition of sulfolane into a light-black polymer(a mixture of polybutadiene and ferrous oxide) and SO(2). For the above reasons, the temperatures for the solvent system and the heating steam should be strictly controlled. When the air is present, due to the oxidation of the air, more SO(2) will be released from the solvent system than when no air is present. Measures should be taken to prevent the air from entering the production system. In practical use of sulfolane, although the products from the decomposition have a certain effect on production, the decomposition of sulfolane solvent can be slowed down by optimizing the nitrogen sealing for the feedstock tank, the solvent tank and the back-washing tank of the extraction system and the mono ethanolamine filling process. Replacing the existing heat exchanger in the extraction section can prevent the corrosion of the products from the decomposition of sulfolane to the heat exchanger; expanding the capacity of the lean solvent heat exchanger and washing the extraction tower on a regular basis can raise the production load of the extraction tower and ensure product quality; adjusting the operating parameters of the dimethylbenzene tower can reduce the decomposing speed of sulfolane and the corrosion to the heat exchanger of the dimethylbenzene tower. 
Environment Abstracts; Gasoline; Solvents; Temperature; Toxicity; Decomposition; Benzene; Heat exchangers; Corrosion; Nitrogen; ENA 01:Air Pollution