A comparative study of three different methods for flare gas recovery of Asalooye Gas Refinery

摘要

Today's world is facing global warming as one of its main issues. A rise in carbon dioxide and other greenhouse gases concentration in the atmosphere causes this problem. A suggested method for controlling the level of greenhouse gases in the atmosphere is prevention of flaring gas. In this work, three methods are proposed to recover gas instead of conventional burning in a flare at the Asalooye Gas Refinery. These methods aim to minimize environmental and economical disadvantages of burning flare gas. The proposed methods are: 1) Gas-to-Liquid (GTL) production, 2) electricity generation with a gas turbine and, 3) compression and injection into the refinery pipelines. In order to find the most suitable method the required equipments for the three aforementioned methods are simulated. These simulations determine the amount of flare gas, the number of GTL barrels, the power generated by the gas turbine and the required compression horsepower. The results of the simulation show that 48,056 barrels per day of valuable GTL products is produced by the first method. The second method provides 2130 MW electricity and the third method provides a compressed natural gas with 129 bar pressure for injection to the refinery pipelines. In addition, the economics of the flare gas recovery methods are studied and compared. The results show that for the 356.5 MMSCFD of gas flared from the Asalooye Gas Refinery, GTL production provides the greatest rate of return. However, GTL requires the greatest capital investment. Gas compression yields the next highest rate of return and due to the lower capital requirements is the best choice for the Asalooye Gas Refinery. This new process is a suitable alternative to conventional gas flaring which prevents harmful environmental effects through emission of significant amounts of carbon dioxide in the atmosphere.