At PT Arun, there are six LNG trains, each with its own treating system. The acid gas treating unit is the front end process of each LNG train, which reduces the CO2 content of the feed gas from 14.85 volume % to less than 0.05 volume % and the H2S from 80 ppm to less than 5.0 ppm by volume. Each treating unit was originally designed to process 314,359 Nm3/h of sour feed gas by using a proprietary Benfield Hi-Pure process.

In late 1979, a study was conducted by Bechtel Inc. to improve the treater capacity and reliability. At that time, modifications were made to the packing, exchangers, and piping, the capacity was improved from it's original design.

In 1983-84, a debottlenecking study was conducted to improve the train LNG capacity and concluded that both the carbonate and amine absorbers were a bottleneck. It was determined that the limitation in the unit was due to poor liquid distribution in the tower packing. The absorber liquid distributors were changed from a "V-Notch" to an "Orifice Riser" type, improving the treating capacity approximately 22% to 28%.

Presently, a new improved liquid distribution system has been installed in one of the the train's carbonate regenerator. This improved the regenerator efficiency from 170 to 190 SCF CO2/LB mole steam. We are now proposing to install this new type of distributor in the remaining five trains in the next scheduled shutdowns (1988-89). A continuing effort to improve the plant treating capacity is still on going at the Arun NGL plant.

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