INVESTIGATING CONSTRAINTS ON CO_2 REMOVAL AT THE IN SALAH GAS PLANT

摘要

The Krechba Central Processing Facility is operated by Sonatrach, BP, and Statoil as part of the In Salah Gas JV, and processes nearly 1 BCFD of gas from three remote fields spread out over the Sahara Desert in central Algeria. One of the primary functions of the plant is to remove CO_2 from a feed stream containing up to 6.6%(mol) in order to meet the export specification of 0.3%(mol) by utilizing two Acid Gas Removal Unit (AGRU) trains incorporating an activated BASF licensed MDEA solution. In recent years, AGRU facilities have had to operate under a variety of operating conditions, ranging from high and low inlet gas rates, varying CO_2 concentrations, and extreme variations in local temperature conditions. Throughout these conditions, several formal and informal plant tests have quantified an unknown constraint that reduces the capacity to remove CO_2 from the bulk gas stream by as much as 10%. This paper discusses the current performance of the Krechba AGRU and the actions taken so far to determine the root cause of the loss of capacity, including the potential causes and resolutions. Based on current experience, the loss of AGRU capacity is thought to be associated with the high rates of glycol contamination and the inability to maintain adequate activator levels in the amine stream.