Process and apparatus for online rejuvenation of contaminated sulfolane solvent

Abstract

A continuous online process for rejuvenating whole stream of contaminated lean sulfolane in an extraction system is provided. In particular, a rejuvenator is installed in the solvent circulation loop to remove the contaminants continuously to keep the solvent clean, effective and less corrosive. Specifically, the rejuvenator comprises a high pressure vessel with a removable cover and a round rack with vertical stainless steel tubes fitted in the high pressure vessel. A magnetic bar is placed in each stainless steel tube. A screen cylinder is installed inside the ring of stainless steel tubes. As the contaminated sulfolane is passed through the rejuvenator, the rejuvenator picks up its contaminants. The rejuvenator can be dissembled to remove the contaminants periodically. The rejuvenator is characterized by simple in construction, reliable in operation, and low in operation and maintenance costs. With this rejuvenator, the extraction system can be operated at high efficiency and high capacity without the dreaded corrosion.

Description

FIELD OF THE INVENTION[0001]The present invention relates to a process for on line rejuvenation of contaminated sulfolane solvent in an aromatic extraction system continuously to maintain the solvent quality at the desired level. More particularly, it relates to a process employing a novel rejuvenator in the circulation loop to remove the sulfolane degradation and corrosion products, including acids, polymers and small solid particles of iron and sand to maintain the solvent at a high quality level, and in turn, a high operation efficiency and a low corrosion extraction system. Moreover, by removing these contaminants, the rate of sulfolane degradation is greatly reduced, leading to minimum consumption of sulfolane. The present invention is characterized by high efficiency for contaminants removal, simple construction, and low operation and maintenance costs.BACKGROUND OF THE INVENTION[0002]Sulfolane, C4H8O2S is also known as tetrahydrothiophene-1, 1-dioxide and tetramethylene sulfo...

AI Technical Summary

Benefits of technology

[0028]The present invention provides a continuous process for rejuvenating contaminated sulfolane in the circulation loop of an aromatic extraction system to a quality substantially the same as the fresh sulfolane. In particular, the process employs a novel rejuvenator to rejuvenate the contaminated sulfolane solvent by removing the degradation and corrosion products from the total stream in the circuit to keep the capacity and operation efficiency of the aromatic extraction system high.

[0030]As the contaminated sulfolane enters the rejuvenator, the degradation and corrosion products are attracted and adhere to the vertical stainless steel tubes filled with powerful magnetic bars, and removed from the solvent system. The removal of the degradation and corrosion products by the magnetic bar is enhanced by the presence of the inner screen cylinder. This enhancement becomes crucial when the level of residual degradation and corrosion products is to be kept low. Through the inner screen cylinder, the rejuvenated, clean sulfolane leaves the rejuvenator and is recycled back to the extraction column. After on stream for a certain period, say two weeks, the rejuvenator is loaded with the degradation and corrosion products and the pressure drop across the rejuvenator increases. The stream is switched to the spare rejuvenator and the degradation and corrosion products loaded rejuvenator is opened to remove the round tray along with the magnetic bars. The round tray with the magnetic in the vertical tube is placed in a container and the magnetic is removed from the tube. Upon removal of the magnetic bars, the degradation and corrosion products fall from the vertical due to removal of the magnetic bars and loss of the attractive force. The system is characterized by high efficiency for contaminants removal, simple construction, and low operation and maintenance costs.

[0035]4) Stable operation capacity and efficiency by maintaining the quality of sulfolane at nearly the fresh level.

Problems solved by technology

Upon removal of the magnetic bars, the degradation and corrosion products fall from the vertical due to removal of the magnetic bars and loss of the attractive force.

Images