L. P. G. Recovery

Abstract

Abstract Four major sour gas processing plants are operated in Alberta by Gulf Canada Resources Inc. At each of these plants, with the exception of Strachan, fractionation systems are utilized to provide for extraction of propane, butane and pentanes plus. Strachan producer LPG mix which is pipelined and fractionated at a jointly owned, partner-operated facility at Fort Saskatchewan. This paper discusses the expander-type facility at Strachan the ambient oil system at Pincher Creek, and low-temperature oil system operation at Rimbey and Nevis for the recovery of L.P.G. Introduction Gulf Canada Resources Inc operates four major sour gas processing plants in Alberta which contain Liquefied Petroleum Gas (L.P.G.) recovery facilities. These plants are at Pincher Creek, Rimbey, Nevis and Strachan. At each of these plants, with the exception of Strachan, fractionation systems are utilized to provide for the extraction of propane, butane and pentane plus_ The Strachan Plant produces L.P.G. mix which is pipelined and fractionated at a jointly owned partner-operated facility near Edmonton. The Rimbey and Nevis plants employ a refrigerated absorption oil system for L.P.G_ recovery Pincher Creek still uses an ambient temperature absorption system. The Strachan Plant, the most recently constructed, utilizes an expander-type facility. In this paper, the systems of L.P.G. recovery used by Gulf Canada in Alberta win be discussed; that is, the expander-type operation and the oil absorption system_ This latter process will be divided into three categories: the ambient oil system, such as used at Pincher Creek, the low-temperature operation used at Rimbey and the Nevis system. Gas Plant Statistics Before proceeding further, Table 1 is included to provide some statistical data. Briefly summarizing, the Rimbey Gas Plant is by far the largest plant Gulf Canada operates, processing 70%. more gas than its nearest rival, the Strachan Plant. Rimbey produces approximately 15,000 BPD of propane and butane and 6,000 BPD of pentane plus. Strachan generates a total of 2,000 BPD of L.P.G. mix and 5,000 BPD of pentane plus. Absorption Oil Recovery Systems As mentioned previously, each gas plant Gulf Canada operates utilizes a different system to recover L_P.G. products. In order to define clearly these differences, the facilities used at each plant will be described and some of the more pertinent aspects emphasized. Pincher Creek The Pincher Creek Gas Plant(l) was constructed in 1956 and was one of the pioneers in sour gas processing in Alberta. The plant was originally designed to process 200 MMCFD but, because of declining reservoir pressure and deliverability, gas volumes from Lookout Butte have been brought in to utilize the processing facilities. In 1976, Pincher Creek processed 70 MMSCFD of sour gas and 3,300 BPD of liquid. The combined raw gas composition and simplified flow diagram are shown in Figure 1. The feed to the plant comprises fluid from two gas fields (Fig. 2)-Pincher Creek, which enters the plant at 190 psig, and Lookout Butte, which is compressed in the field some 15 miles away and is then pipelined to the Pincher Plant, where it enters at 1000 psig.