In the present study, a coal-integrated gasification combined cycle power plant is simulated. A high-ash coal and low-ash coal are considered to compare the performance of the plant. The combined cycle is in typical commercial size with 450 MW capacity. The feeds are Tabas and Illinois #6 coals which approximately contain more than 30% and 10% ash and have higher heating values of 22.7 MJ/kg and 26.8 MJ/kg, respectively. Energy and exergy analyses are done by aspen plus^® and ees, respectively. Energy analysis shows that the overall efficiencies of power plants using high-ash and low-ash coals are 33% and 28%, respectively. The result shows that in high-ash case, 52 kg/s coal, 10 kg/s water, and 1050 kg/s air and in low-ash case, 48 kg/s coal and 820 kg/s air are required for providing mentioned power, approximately. Exergy analysis shows that maximum exergy destruction is in heat recovery steam generator unit. Investigating the emissions shows that high percent of ash in the coal composition has slight effects on the IGCC pollution. Finally, from thermodynamic viewpoint, it is concluded that the high-ash coal, like the conventional one, can be used as thermally efficient and environmentally compatible feed of IGCCs. Copyright © 2016 John Wiley & Sons, Ltd.

In this paper gasification performance of Mazut of Iran’s refineries based on Gibbs free energy minimization is studied. A parametric study was performed in order to investigate the effects of different agents (oxygen, air, and steam), equivalence ratio and gasifier pressure on syngas composition, gasification temperature, high heating value, cold gas efficiency, and exergy efficiency. The results of oxygen-gasification show that Mazut can be employed in the integrated gasification power generation systems and provides constant and appropriate exergy efficiency contents. Additionally, mazut gasification with air-steam or oxygen-steam is more efficient in order to produce syngas for chemical applications. The present study assesses syngas compositions and gasification performance characteristics for different operating conditions.

Gasification of high-ash coal in dry and slurry entrained flow gasifiers is investigated through equilibrium modeling. Effects of oxygen- and steam-to-coal mass flow rate ratios in a dry-fed gasifier and also the effect of water concentration in slurry on composition, temperature, heating value, and cold gas efficiency are studied. It is observed that adding steam to the gasifier reduces oxygen consumption, and the optimum ratio of oxygen-to-coal mass flow (O/F) decreases. At high enough O/F ratios, the steam-to-coal mass flow (S/F) and water-to-coal mass flow (W/F) ratios have no significant influences on gasifier efficiency. It is also observed that for coal, which has a high ash content, dry-fed gasification is preferable. In this type of gasifier, optimum O/F and S/F ratios with respect to cold gas efficiency are determined to be 0.5 and 0.8, respectively. Simulation of the integrated gasification combined cycle (IGCC) in Thermoflow indicates that, for a typical 450-MW combined cycle, 56.6 kg...

In this research, the supercritical water gasification for a sort of heavy fuel oil, Mazut, has been investigated. Mazut was modeled with a 33-pseudo-component using the corresponding distillation curve. In a reactor, the equilibrium reactions were simulated using the Gibbs free energy minimization method. A parametric study was performed on this system. The parameters were included mass fraction of fuel and pressure and temperature of the gasifier. Two approaches were investigated, one with constant pressure (P = 22.1 MPa) and the other with constant temperature (T = 600°C), varying the other two parameters. H₂ production efficiency reaches a maximum at fuel mass fraction about 30 percent and gasifier temperature in the range of 500°C to 700°C.