Abstract: The technology of fiber membrane was adopted in the LPG sweetening system of SINOPEC Qingdao Refining and Chemical Co. Ltd. The small molecule mercaptan and H₂S in LPG reacted with alkali solution to generate sodium mercaptan compound and sodium sulfide，which was dissolved in alkali solution to realize the removal of mercaptan and H₂S. In the operation，the fiber surface had obvious scaling tendency. When the fiber is scaling and entangled，the alkali liquor couldn't be uniformly dispersed，and the liquefied gas "short circuit" would occur. If the contact between alkali liquor and LPG was not enough，the mercaptan content in refined LPG would exceed the standard. Through the solution potentiometric titration and X-ray spectrum analysis of the scale sample on the fiber surface，it was found that the main component was Na₂CO₃. Aspen Plus was used to simulate and calculate the operation conditions of the sweetening system to find out the optimization operation conditions to ensure the long-term operation of the fiber membrane contactor.

Key words: carbonyl sulfur, mercaptan removal, fiber membrane, regeneration temperature, solubility