Sweetening of Sour Crude Using Gas Stripping Process

A reduction of the hydrogen sulfide content of crude oil can be accomplished by stripping with gas in a contact tower at low pressures. In addition, stabilization of the oil or condensate is accomplished simultaneously with less shrinkage and tank losses as compared with multi-stage separation. Several simplified processes can be utilized to accomplish the desired results and are discussed in the paper. A computer program is available which will simplify the tray-by-tray equilibrium calculations for design purposes. The process can be adapted to purposes. The process can be adapted to both small and large installations and sulfur recovery from the sour overhead vapor may be added to the larger installations in order to accomplish a shorter payout. Also some form of hydrocarbon recovery from the stripping and flash gas would be desirable in areas where gas liquids have any value. Design and installation of a unit was made which reduces the sulfur content from 500 ppm to less than 30 ppm using sweet natural gas for stripping and at the same time reduces the vapor pressure to less than 15 psia @ 100 degrees F to prevent vaporization losses during transportation in warm ocean waters. The processes shown herein afford a method whereby the H2S content of sour crude oil or condensate can be reduced at the production site. This helps to produce production site. This helps to produce a more valuable product and prevent pollution problems before they occur pollution problems before they occur in the more populated refinery area. Introduction Sweetening of sour crudes has recently become more important with the advent of new pollution control regulations and increased refinery treating costs. The stripping process utilizes Henry's law which states that the amount of a slightly soluble gas that dissolves in a liquid at a given temperature is very nearly proportional to the amount of the particular gas in the surrounding atmosphere.