ECONOMICS OF ACID GAS REINJECTION: AN INNOVATIVE CO_2 STORAGE OPPORTUNITY

摘要

Acid gas streams, consisting primarily of hydrogen sulfide (H_2S) and carbon dioxide (CO_2), are commonly generated as a by-product of the gas sweetening process used to bring produced gases and solution gases up to pipeline specifications for sales and transport. In the past, the conventional methods for acid gas disposal are to use a Claus process or to flare the acid gas. A new technology called acid gas reinjection has emerged over the past ten years in Canada as an effective way of ensuring that acid gases are not emitted into the atmosphere. There are 38 acid gas reinjection projects presently operating in Alberta. This technology involves compressing the acid gas and injecting it into a suitable underground zone, similar to deep well disposal of produced water. Essentially, the sulfur compounds and CO_2 are permanently stored in the deep geological formation preventing their release to the atmosphere. Therefore most acid gas reinjection projects can be considered as existing examples of CO_2 geological storage projects. These projects provide important practical experience with CO_2 storage. In addition, this technology could be extended to capture a significant fraction of the natural gas-associated CO_2 stream at low cost. In this paper, a cursory economic analysis is made on one of the Alberta acid gas reinjection projects relative to sulfur recovery for determining the amount of CO_2 avoided. I