Investigating a Process Upset at Badak LNG Plant
One of a process engineer role is to conduct an investigation for plant upset to find the root cause and take the lessons learn to avoid recurrence. One case the I have to handle was when Train-A experienced high CO2 breakthrough from the Acid Gas Removal Unit or CO2 Absorber. I have to read the operating manual and theory of absorbtion to be able to understand what happen and conduct investigation. The incident happened during a start-up. I was thinking if the problem related to the low feed gas flow to the Absorber. Based on the operating manual there is a minimum feed gas velocity that must be kept to establish a good contact at the trays. Otherwise, the liquid absorbent (MDEA) could be weeping through the holes of the tray which minimizes contact with the feed gas.
Using this finding, I calculated the feed gas velocity when the incident happen. I can proof that it was below the minimum velocity required. I discussed this finding with my senior processs engineer at that time and they all agreed. I also discussed it with operations panel operator and supervisor. In the report, I recommended to maintain feed gas rate at 50,000 Nm3/hr during start-up. Operations took the advise and the pro
blem can be avoided.