A review of Unit operations and Processes of Gas Processing Plants

Gas plant is a processing unit that used for processing operation, preparing and properties  optimization of extracted gas from gas wells, inorder to changing gas to a usable product. In a gas processing plant separating operation of components which cause reduction of heating value and operating problems in gas transmission and consumption, will be done and the processed gas will be delivered to transmission pipelines. In general case, equipments of a gas plant will be divided in to two parts, off shore and on shore. Although depending on the place of gas plant, it is possible that all of the equipments belong to the on shore part, in another word the feed doesn’t originate from the fields in sea. Off shore part is composed of two parts, wellhead platform and sea pipelines, that used for extraction and transmission of gas plant feed. On shore part is composed of three main parts, operating, utility facilities and storage tanks. Also subdivisions of these parts are the same in all plants, but it is possible depending on special duty of each plants designing purpose, some units were different from other plants. For example in fourth plant of south pars, there is no gas sweetening unit because in this gas plant natural gas will be transmitted to the Aghajari oil field after condensates separation and dew point adjustment, and LPG sweetening is the only sweetening operation there. However in other gas plants sweetening operation along with the above operation will be done inorder to gas preparing for consumption purposes (like domestic consumption). So units sequence will be determined according to designing issues.