TASK 1:
Question: The diagram below shows the process of electricity production.
ANSWER:
The diagram illustrates how electricity is produced using a coal-based integrated gasification combined cycle (IGCC) system. Overall, the process involves two main stages: coal is first converted into purified syngas to generate electricity through a gas turbine, and then the waste heat from this stage is reused to produce steam for further power generation.
Initially, coal is fed into a gasification furnace, where it reacts with oxygen to form raw syngas, while solid by-products such as slag are removed. The raw syngas then passes through a cleaning unit, in which pollutants including carbon dioxide, mercury and sulphur are eliminated, resulting in purified syngas. This clean gas is subsequently supplied to a gas turbine, which drives a generator to produce electricity.
Meanwhile, the hot exhaust gases released from the gas turbine are directed to a heat recovery steam generator, where their residual heat is used to produce steam. This steam powers a steam turbine connected to another generator, generating additional electricity. Finally, electricity from both generators is transmitted to the grid, and flue gases are released after heat recovery, completing the electricity production process.
