Natural gas sweetening process simulation and optimization: A case study of Khurmala field in Iraqi Kurdistan region

Natural gas is the most important and popular fossil fuel in the current era and future as well. However, because the natural gas is existed in deep underground reservoirs so it may contain several non-hydrocarbon components for example, hydrogen sulphide and carbon dioxide. These impurities are undesirable compounds and cause several technical problems for example, corrosion and environment pollution. Recently, the Iraqi Kurdistan region has achieved huge development in many fields for example, education, economic and oil and gas industry. In fact, Khurmala dome is located in southwest Erbil- Kurdistan region. The Kurdistan region government has paid great attention for this dome to provide the fuel for Kurdistan region. However, the Khurmala associated natural gas is currently flaring at the field. Moreover, nowadays there is a plan to recover and trade this gas and to use it either as feedstock to power station or to sell it in global market. However, the laboratory analysis has showed that the Khurmala natural gas has huge quantities of H2S about (5.3%) and CO2 about (4.4%). Therefore, this study aims to simulate the prospective Khurmala gas sweetening process by using the latest version of Aspen HYSYS V.7.3 program. Moreover, the simulation work is adopted amine gas sweetening process by using DEA solution and it achieved high acid gases removal for instance, H2S concentration in sweet gas stream was about 4 ppm at (400 m3/h) amine circulation rate. In addition, the simulation work is also achieved process optimization by using several amine types and blends for example, MEA and MDEA. It also examined some of the critical amine process factors for each amine type for example, amine circulation rate and amine concentration. Moreover, the optimization work found that the use of (DEA 35% w/w) may consider the most recommended process.