LESSONS LEARNED AND TECHNOLOGY IMPROVEMENTS AT THE LOST CABIN GAS PLANT

摘要

Burlington Resources' Lost Cabin Gas Plant (LCGP) Train 3 started up in September 2002. This train has a design capacity of 180 MMSCFD, with an ultimate capacity of 200 MMSCFD, increasing total facility capacity to more than 300 MMSCFD. LCGP feed gas contains approximately 68 percent methane, 12 percent H2S, 20 percent CO2, 400 ppm COS, and traces of elemental sulfur. This mixture presents unique design and operating challenges for treatment. The higher feed gas flow rates to the plant from existing and new deep wells result in plant feed gas temperatures as high as 300 oF. This increased temperature and presented additional challenges for design of the integrated Trains 1, 2 & 3 inlet gas cooling equipment that solidifies and removes most of the elemental sulfur before it enters the gas treating system. Operating experience and equipment improvements in Trains 1 and 2 were reported previously at the 2000 LRGCC. This paper discusses additional “lessons learned” and design improvements incorporated in Train 3, and reports actual operating experience with the modified facility. Primary topics include the following: Cooling of the feed gas, handling of the cooling and condensed waters, and integration of these functions among Trains 1, 2 & 3 Sulfur removal from the feed gas and cooling water Selective solvent (Selexol) system design and operation modifications to increase COS retention in the concentrated H2S acid gas produced in the first-stage treating system. This modification reduced COS emissions from the CO2 stream vented in the second-stage treating system Elimination of redundant equipment SCOT amine cooling