Baseline Testing of the Stretford Process on the GRI 120-Liter Bench-Scale Liquid Redox Sulfur Recovery Unit. Topical Report

摘要

Liquid redox sulfur recovery processes are of interest to the natural gas industry for treatment of sour reserves of conventional gas and of substitute natural gas (e.g., gas produced from gasifying coal). These processes offer high H2S removal efficiency, one-step treatment, low energy requirements, the ability to handle low- and high-H2S streams, and a regenerating catalyst. Sulfur is removed as gaseous H2S and converted either to sulfur cake, a disposable waste, or to elemental sulfur which can be sold. Liquid redox processes have complex chemistries and can experience operating problems and less-than-design performance. This class of processes includes Hiperion, LO-CAT, Stretford, SulFerox, Sulfolin, and Unisulf. The Gas Research Institute's liquid redox sulfur recovery research program has initially focussed on gaining a better understanding of the Stretford process. Stretford is the oldest of the liquid redox processes and has over 100 plants in operation. The factors examined were feedgas CO2 and H2S concentrations, pH, temperature, ADA concentration, citrate, air rate, and reactor residence time. The second objective of the testing was to compare the performance of the 120-liter (32 gallon) GRI bench unit to the 500 gallon pilot unit at the Great Plains Gasification Plant (GPGP) near Beulah, North Dakota.