This project relates to the production of methanol from a gasification coal process at Tarong Power Plant. The gasification process produces syngas (CO + H2) which can be further processed for methanol production. Crude methanol is the initial product which requires further distillation in order to meet the final product specifications as Chemical Grade AA methanol, Fuel Grade Methanol and MTBE Grade Methanol.
Coal is a combustible mineral that contains more than 50% w/w of carbonaceous material. Coal gasification technology is the latest “clean coal technology” whose resulting product gases such as CO2, CO, H2, CH4 and others can be used to produce methanol, low sulphur diesel or hydrogen for fuel cell applications. The technology will also reduce gaseous emissions to the environment, which results in reduction of environmental pollution impact such as the greenhouse effect, acid rain, and photochemical smog.
Gasification is defined as conversion of coal to produce gases such as CO, H2, CH4 and others. The syngas mainly (CO + H2) is fed to a liquid fuel plant to produce low sulphur diesel, methanol or perhaps hydrogen. There are many types of gasifier design such as the entrained flow gasifier, moving bed gasifier, fluidized bed gasifier and fixed bed gasifier. Typically there are two stages of gasification before syngas is produced- pyrolysis and gasification/ combustion. The descriptions of various gasifiers are given in the literature review section. The syngas is fed to cleaning technology units such as particulate matter removal units, water removal units, sulphur removal units and carbon dioxide removal units before being fed to the methanol synthesis unit. 2 main processes take place in the methanol synthesis plant- water gas shift reaction and Low Pressure Methanol process to produce crude methanol before is delivered to purification units for further purification. By- products, especially steam, can be used for power generation application to produce additional electricity.
In addition to the literature review this thesis also consists of a PFD of a methanol synthesis plant and ASPEN simulation model analysis. This is important to ensure the liquid fuel plant operates under a safe and effective regime.