Low-Cost Approach to Significantly Reduce Operational Cost and Improve Facility Reliability in Banyu Urip Acid Gas Removal Unit (AGRU)

Abstract

Abstract Acid Gas Removal Unit (AGRU) is used for fuel gas (FG) production in Banyu Urip Facility, Indonesia. AGRU was operated at the 50% design capacity due to low FG demand with several operation limitations due to AGRU Wet Surface Air Cooler (WSAC) poor performance. This condition led to off-spec fuel gas production with higher H2S and high temperature which adversely impacted fuel gas compressor (FGC) reliability. Consequently, frequent problem in FGC interrupted FG supply to Gas Turbine Generator (GTG) and lead to excessive diesel consumption to substitute FG for electricity generation in the facility. This causes a high operational cost. Additionally, the facility could not be pushed to operate in higher rate for production optimization. The WSAC improvement then became critical to sustain FG supply and reduce operational cost. Debottlenecking study to improve AGRU system performance was performed resulting in several improvement initiatives. Based on the study, significant heat transfer deterioration was observed at the WSAC 1st stage due to higher operating temperature compared to the 2nd stage. In addition to this, some required design improvements were also identified based on learning from historical failures such as water sprayer upgrade to anti-clogging type, motor and fan replacement for better induced draft cooling, and plenum material upgrade for better corrosion resistance. Therefore 1st stage bundle replacement with upgraded design was progressed. Post tube bundle replacement and combine with the chemical treatment, the AGRU WSAC heat transfer performance was increased by 75% and GTG diesel consumption was reduced substantially by ~70%. This contributed to $1M annual operational cost saving with project investment at only $650K. This fit for purpose project is more beneficial compared to the whole WSAC replacement which costs $2.4M. This condition also provided flexibility to run more GTG to produce more power for the facility. Additionally, by allowing more gas to be processed in AGRU, it helped the facility to optimize oil production.