Technical and Economic Comparison of Lo-Cat II
Publication Date: 2009-Apr-09
The IP.com Prior Art Database
Presented at 1992 GRI liquid Redox Sulfur Recovery Conference
4 - 6 October 1992, Austin, Texas
TECHNICAL AND ECONOMIC COMPARISON OF lO-CAT IITM
WITH OTHER IRON-BASED LIQUID REDOX PROCESSES
Michael P. Quinlan and linda W. Echterhoff
The M. W. Kellogg Company, Houston, Texas
Gas Research Institute
Contract No. 5088-221-1753
Technical and Economic Comparison of lO-CAT fIllll With Other Iron-Based liquid Redox Processes
The traditional method of removing H2S from sour natural gas is to first treat the gas with a solvent to remove the H2S and then to recover the H2S as molten sulfur in a sulfur plant. This method recovers up to 97% of the sulfur when a 3-stage Claus sulfur recovery unit (SRU) is employed. Higher recoveries of sulfur require the addition of some form of tail gas clean-up unit (TGCU).
For small capacity SRU's [< 10 tons per day (TPD) of sulfur), Claus plants are difficult to operate and control. As heightened environmental awareness has led to increasingly higher mandated sulfur recovery levels being applied to smaller SRU plant capacities, operators have looked to alternate processes such as liquid redox to remove the H2S and recover the sulfur for their small-scale sour gas treating applications.
The most popular of the redox processes are those that use either a vanadium (e.g., Stretford, Unisulf) or an iron (e.g., LO-CAT®, LO-CAT 11111, SulFeroxSM) base. Presently, environmental concerns about the vanadium content of the blowdown stream have resulted in selection of the iron-based processes for most recent applications.
There are now over 70 LO-CA T units, 4 LO-CA T " units (and 6 others planned), 14 SulFerox units (and 6 others in the initial phase of the licensing process) and 2 Sio-SR units in operation or under license. A significant number of these units are in natural gas sweetening applications, and their number continues to grow.
Under contract to the Gas Research Institute (GRI), The M. W. Kellogg Company has performed a comprehensive evaluation of the iron-based liquid redox processes (LO· CAT, lO-CAT II, SulFerox and Sio-SR). GRI has been carrying out a program of research and development (R&D) in natural gas processing since 1989. The primary objective of GRl's Gas Processing R&D program is to develop technologies that will reduce the cost or enhance the environmental benefits associated with treating and processing subquality natural gas to achieve pipeline quality gast1l• The program
includes activities in acid gas removal, dehydration and condensibles removal, nitrogen rejection, instrumentation and control, and technical evaluation. GRl's research activities in sulfur removal from natural gas and liquid redox have been previously addressed 121. The purpose of the present study...