Based on additional information, M.W. Kellogg Co. revised the index of selection (IOS) for H2S scavengers used in natural gas conditioning that appeared in OGJ, May 23, p. 55. The table ranks the scavenger effectiveness for 3, 60, and 100 lb of sulfur/day.
The iron sponge scavenging process was widely used by the industry for many years but recent safety and environmental concerns associated with the disposal of the spent wood chips has prompted the need for new methods.
M.W. Kellogg's work is part of a Gas Research Institute (GRI) study to determine economical methods for removing relatively small amounts of sulfur from natural gas. Scavengers are typically used in gas streams with less than 200 ppm H2S.
This relative index weights each factor depending on site-specific or other conditions. Factors included in this index and the weights are as follows:
- Total plant investment (1.0)
- Operating cost (1.0)
- Process reliability (1.0)
- Winterization (0.2)
- Ease of operation (0.5)
- Operators' acceptance (0.4)
- Disposal of spent material (1.0)
