TECHNICAL AND OPERATING SUPPORT FOR PILOT DEMONSTRATION OF MORPHYSORB ACID GAS REMOVAL PROCESS

Abstract

Over the past 14 years, the Gas Technology Institute and jointly with Uhde since 1997 developing Morphysorb{reg_sign} a new physical solvent-based acid gas removal process. Based on extensive laboratory, bench, pilot-plant scale experiments and computer simulations, DEGT Gas Transmission Company, Canada (DEGT) has chosen the process for use at its Kwoen processing facility near Chetwynd, British Columbia, Canada as the first commercial application for the Morphysorb process. DOE co-funded the development of the Morphysorb process in various stages of development. DOE funded the production of this report to ensure that the results of the work would be readily available to potential users of the process in the United States. The Kwoen Plant is designed to process 300 MMscfd of raw natural gas at 1,080-psia pressure. The sour natural gas contains 20 to 25 percent H{sub 2}S and CO{sub 2}. The plant reduces the acid gas content by about 50% and injects the removed H{sub 2}S and CO{sub 2} into an injection well. The Kwoen plant has been operating since August 2002. Morphysorb{reg_sign} is a physical solvent-based process used for the bulk removal of CO{sub 2} and/or H{sub 2}S from natural gas and other gaseous streams. The solvent consists of N-Formyl morpholine and other morpholine derivatives. This process is particularly effective for high-pressure and high acid-gas applications and offers substantial savings in investment and operating cost compared to competitive physical solvent-based processes. GTI and DEGT first entered into an agreement in 2002 to test the Morphysorb process at their Kwoen Gas Treating Plant in northern BC. The process is operating successfully without any solvent related problems and has between DEGTC and GTI. As of December 2003, about 90 Bcf of sour gas was processed. Of this about 8 Bcf of acid gas containing mainly H{sub 2}S and CO{sub 2} was injected back into the depleted reservoir and 82 Bcf sent for further processing at DEGTC's Pine River Plant. This report discusses the operational performance at Kwoen plant during the performance test as well as the solvent performance since the plant started up. The Morphysorb performance is assessed by Duke Energy according to five metrics: acid gas pickup, recycle gas flow, total hydrocarbon loss in acid gas stream, Morphysorb solvent losses and foaming related problems. Plant data over a period of one year show that the Morphysorb solvent has performed extremely well in four out of five of these categories. The fifth metric, Morphysorb solvent loss, is being evaluated over a longer-term period in order to accurately assess it. However, the preliminary indications based on makeup solvent used to date are that solvent losses will also be within expectations. The analysis of the solvent samples indicates that the solvent is very stable and did not show any sign of degradation. The operability of the solvent is good and no foaming related problems have been encountered. According to plant operators the Morphysorb unit runs smoothly and requires no special attention.