Propylene Tower Revamp in Gas Separation Plant
Location: Fujian Province, China
Start-up time: Jan., 2001
Original capacity of gas separation plant was 180 Kt/a where propylene tower had 200 layers of V1 valve trays. Before revamping, performance of this plant was good and separation efficiency of propylene tower was also good within 200 Kt/a. Once capacity was larger than 200 Kt/a, separation efficiency of propylene tower obviously decreased.
Capacity of gas separation plant was expected to be 270 Kt/a due to the constantly rising price of propylene product.
Based on overall calculation for whole plant by SEI, depropanizer and propylene tower should be revamped. Client decided to adopt ADV® high performance tray to revamp these two towers after contrast with other vendors, with following demands: Yield and purity of propylene should be no less than 10545 kg/h and 99.6 mol%, respectively; Purity of propane should be no less than 92 mol%.
Original valve trays were replaced by ADV® valve trays one by one. The following technologies were adopted:
(1) Increased DC area and adopted sloped DC;
(2) Adopted bubble promoters to improve bubble status and increase open area;
(3) Adopted “Quick-connect” active tray joint methods to further increase open area;
(4) Adopted unique T-shape beam to support center seal pans;
(5) Optimized feed location of propylene tower.
Capacity of this plant reached to 270 Kt/a soon after it was started-up in Jan., 2001 and maximum capacity was 288 Kt/a. Propylene content from top product of propylene tower was larger than 99.7%. Propane content was 99.8% in bottom product, which was only 95% before revamping. Both capacity and tray efficiency were improved.
Propylene product was increased by 39 Kt/a based on production in 2004. Payback period of revamping plant was less than 3 months.
Currently, it has the highest tray efficiency of propylene tower in contrast with others for ZEHUA.