Comparative Economic Investigation Options for Liquefied Petroleum Gas Production from Natural Gas Liquids

Abstract

There is new trend in the value of oil and gas in the world, with the value of Liquefied Petroleum Gas (LPG) soaring higher. It is due to its uses as a potential fuel in the several parts of the world, its demand in the petrochemical industries for plastics and automotive composites productions, and other uses. These results in steadily increases in price. There is also increase in volume of feed gas, which demands efficient LPG processing and recovery technology. This paper mainly focuses on comparative economic investigation options for Liquefied Petroleum Gas plant, which processes feed from natural gas wells and dehydrating units to produce Liquefied Petroleum Gas along with natural gasoline having a higher value as separate product. Recovery of LPG is possible but raises both the initial cost of plant and operational cost considerably. The value of LPG recovered should be high enough to widen the operating margins between the processing costs and the market price for which the recovered liquids can be sold. Therefore, the most economic means of extracting this product must be used. This was done using two alternatives; the Conventional Fractionation process and Single column overhead recycle process (SCORE). Both alternatives were simulated with Hysys and are analyzed based on product recovery level, energy required and fixed capital cost. There are two feeds to the plant, one from the natural gas wells and the other from dehydrating units of natural gas processing plants with a total flow rate of 6.99 MMSCFD. Analysis of result from modeling shows that Single column overhead recycle process has a total product recovery of 97.2 % while Conventional fractionation process has a total recovery of 88.5 %, the require energy margin between the alternatives is about 38.9 % in favor of conventional process and the fixed capital cost is in the favor of Single column process. Sensitive to choosing the most economic option of LPG recovery between the conventional process and SCORE process is the recovery level of LPG from each of the options, total energy required and the cost of the equipment. From the analysis, it shows that, it is more economical to use the Single column overhead recycle process, as compared to conventional fractionation process.