Planning for A Flexible Gas Processing Plant

The main focus ofplanning for aflexible gas processing plant production in this project
is regarding demethanizer. The demethanizer is alarge stripping tower equipped with 40 twosided
valve trays and 3chimney trays. It is also equipped with aconventional steam reboiler at
the bottom, and three side pump around reboiler utilizing liquid draw offe from the chimney
trays. Type ofthe boiler that was used as aheater was vertical thermosiphon reboiler. As
ethane and heavier components are condensed during the cool down process, alarge portion of
the methane component is also condensed from the feed gas. The demethanizer and its related
equipment are designed to strip this methane from the feed to form the overhead sales gas. The
exact composition ofthe overhead will contain more or less ethane and C02? depending on the
feedstock and the operating mode. The overhead temperature is at -64°C while the pressure is
2400 kPaG. The base is at 38°C and about 2420 kPaG. The demethanizer has two products.
Product sales gas from the tower overhead is heated in the Feed Gas Cooler No.2 (T-403) and
No. 1(T-401) as in appendix 1, before going to the train of compressors. Ethane and heavier
hydrocarbons from the tower bottom are pumped to deethanizer as afeed to Product Recovery
Unit(PRU)