Low-quality natural gas sulfur removal/recovery with membranes

The main objective of this program is to develop a membrane process for the separation of hydrogen sulfide and other impurities (carbon dioxide and water vapor) from low-quality natural gas. The overall program involves development and parametric testing of appropriate membrane materials in the form of thin-film composite membranes. These membranes will then be made on a larger scale and incorporated into modules which will be tested first in the laboratory, and then at different field sites. A technical and economic analysis of the membrane process will then be performed and compared with existing, processes. In Phase I of the program, an extensive experimental study has been performed to assess the performance of our membranes under various feed conditions. Composite membranes made from four different polymers were investigated to determine their hydrogen sulfide/methane and carbon dioxide/methane selectivity. Two polymers were then selected for a further parametric study. Effects of the following variables were studied: the feed compositions of hydrogen sulfide and carbon dioxide, the presence of water vapor in the feed gas, and the feed gas temperature. Experiments were performed at pressures in the range 400--1,000 psig. Also as part of the Phase I evaluation, Hoechst Celanese Corporation will performmore » a complete economic analysis for the removal and recovery of a 1 Ton sulphur/day plant. In Phase II of the program, a bench-scale system will be constructed and long term tests will-be performed. Also, this skid-mounted system will then be field-tested at one or more different field sites.« less