Improving Banyu Urip Acid Gas Removal Unit (AGRU) and Acid Gas Enrichment (AGE) System Performance and Reliability by Implementing an Effective Wetted Surface Air Cooler (WSAC) Chemical Treatment Program

Abstract

The Banyu Urip production facility located in East Java, Indonesia; currently produces ca. 30% of the country's daily oil production. Field fluids are sour with high H2S (1.6%) and CO2 (45%) in the gas, which is conditioned prior to it's use as fuel, for Sulphur Recovery, or for reinjection. Gas conditioning takes place in two amine units, the Acid Gas Recovery Unit (AGRU) and the Acid Gas Enrichment Unit (AGE). Both units use aqueous MDEA as the amine solvent, with Wetted Surface Air Coolers (WSAC) used to cool hot lean amine off the regenerator columns. In early operation both conditioning units operated at design case. In the period 2018-2020 however, the WSACs became progressively fouled with scale and algae which led to a decrease in thermal transfer efficiency and a consequential decline in plant performance and reliability. SOx emissions were also impacted negatively. To resolve fouling and its detrimental consequences, a chemical treatment program was developed and implemented. The program involved laboratory qualification of candidate chemicals, including evaluation in a novel pilot skid that accurately simulated WSAC field conditions; followed by extended field trials. System performance was evaluated, which verified the pilot skid test results, and the program was implemented on a continuous basis. Extensive surveillance of multiple chemical and operational parameters was performed, and with critical evaluation of these derived data sets, improvements in operational practices were implemented, and unit performance gains realized. Implementation of the program has improved the reliability of the Fuel Gas Compressors (FGC) reducing monthly Gas Turbine Generator (GTG) diesel consumption rates by a factor of > 6. Secondly, AGE operational improvements reduced net SOx emissions for the facility by ca. 70% (2019 vs 2021) through a reduction in Thermal Oxidizer feed gas H2S content, and in lowering LP flaring.