Avaliação da remoção de sulfeto de hidrogênio do gás natural em uma coluna de absorção

摘要

Natural gas, although basically composed by light hydrocarbons, also presents in its composition gaseous contaminants such as CO2 (carbon dioxide) and H2S (hydrogen sulfide). Hydrogen sulfide, which commonly occurs in oil and gas exploration and production activities, besides being among the gases that are responsible by the acid rain and greenhouse effect, can also cause serious harm to health, leading even to death, and damages to oil andnatural gas pipelines. Therefore, the removal of hydrogen sulfide will significantly reduce operational costs and will result in oil with best quality to be sent to refinery, thereby resultingin economical, environmental, and social benefits. These factors highlight the need for the development and improvement of hydrogen sulfide sequestrating agents to be used in the oil industry. Nowadays there are several procedures for hydrogen sulfide removal from naturalgas used by the petroleum industry. However, they produce derivatives of amines that are harmful to the distillation towers, form insoluble precipitates that cause pipe clogging and produce wastes of high environmental impact. Therefore, the obtaining of a stable system, in inorganic or organic reaction media, that is able to remove hydrogen sulfide without forming by-products that affect the quality and costs of natural gas processing, transport and distribution is of great importance. In this context, the evaluation of the kinetics of H2S removal is a valuable procedure for the treatment of natural gas and disposal of the byproductsgenerated by the process. This evaluation was made in an absorption column packed with Raschig ring, where natural gas with H2S passes through a stagnant solution, being thecontaminant absorbed by it. The content of H2S in natural gas in column output was monitored by an H2S analyzer. The comparison between the obtained curves and the study ofthe involved reactions have not only allowed to determine the efficiency and mass transfer controlling step of the involved processes but also make possible to effect a more detailedkinetic study and evaluate the commercial potential of each reagent