Laboratory Study on the Effects of Alkylation on Malaysian Coal for Coal Bed Methane Study

Alternative energy source such as coal bed methane is gaining huge demand as the world’s energy consumption is increasing every year. Coal bed methane gas is produced from coal seam reservoirs and often produced at shallow depths. Some of the gas is stored in the coal reservoir as free gas and some is held at the surface of the coal by adsorption in the micropores. The adsorbed gas can only be produce when the reservoir pressure is low. The complex structure of the coal makes it harder to produce the adsorbed gas because of the high pressure between the coal cleats. By changing the structure of the coal, the adsorbed gas will be release as free gas since the pressure between the coal cleats has been reduced. Alkylation of coal process is proved to increase the solubility of coal by changing the structure of the coal using alkyl halides. There are many type of alkylation agent for the alkylation process and the quality of the product is depending on them. In this study, the effect of alkylation on the characterization of the coal is determined. The coal sample is first subjected to alkylation process using two different alkylating agents (a straight chain and a branched chain alkylating agents) by refluxing the coal sample with the alkylating agent for 24 hours. It is found that the alkylation process increases the weight of the coal sample by 21.54% when a branched chain alkylating agent is used and only 13.88% when a straight chain alkylating agent is used instead. Apart from alkylating the coal, the characterization using the Fourier Transform Infrared spectroscopy is performed to identify the molecules that are present in the coal. The branched chain alkylating agent gave more infrared absorption peaks as compare to the straight chain alkylating agent. Therefore, a branched and longer carbon chain of alkylating agent used for the alkylation process has more effect on the coal.