Effect of carbon dioxide on hydrogen sulfide scavenging

摘要

Effective removal of hydrogen sulfide (H_2S) is one of the challenging problems associated with the production of natural gas. Since H_2S is often present in natural gas along with varying levels of carbon dioxide (CO_2), selective removal of H_2S from sour gas in the presence of CO_2 is very important for cost effectiveness of a scavenging operation. For over ten years, triazine based scavengers have been successfully applied in the sweetening of natural gas. However, observations of the effect of CO_2 on the scavenging capacity of triazine based scavengers have not been very consistent. Initial documentation and case histories on performance of triazine based scavengers by Dillon reported that CO_2 did not have any effect on the H_2S scavenging capacity of triazine. However, recent studies by GRI indicate that CO_2 significantly reduces the H_2S removing capacity of triazine. To address this discrepency, this paper critically evaluates the effect of CO_2 on the scavenging performance of a triazine based H_2S scavenger. Results from controlled laboratory experiments, using a wide range of CO_2 partial pressure and H_2S to CO_2 ratios indicate that CO_2 has very little efect on the H_2S scavenging performance of a triazine based H_2S scavenger. Field data supports the observations made in the laboratory experiments.