Proposing Various Structrual Alternatives for Acid Gas Enrichment of Khangiran Natural Gas Refinery

Low quality SRU feed stream causes serious operational problems rise like combustion chamber low flame temperature, unburned BTEX components, low quality and impure produced elemental sulfur with dark yellowish color. Low acid gas quality combined with the premature catalyst deactivation will eventually decrease the overall efficiency of the entire Claus process of Khangiran refinery from the standard value of 97% to less than 90%. Using sterically-hindered solvents, promoted tertiary amines or various configuration for gas treating unit is several alternatives for acid gas enrichment (AGE) to reduce the concentration of carbon dioxide and heavy aromatic hydrocarbons while enriching the H2S content of SRU feed stream. The present article compares two distinct enrichment schemes for Khangiran refinery acid gas stream by employing different configuration of gas treatment unit. The results are then compared with each other’s to select the optimal AGE scheme, which can maximize the H2S content of SRU feed stream while minimizes H2S emission to atmosphere. The simulation results revealed that by employing optimal values for the acid gas split ratio, the recycled amine split ratio and the enrichment tower pressure about 0.8, 0.14 and 60, respectively in the second scheme, the SRU feed stream can significantly enriched from its original value of 33.5 mol% H2S to about 70 mol%.