Numerical investigation of slag formation in an entrained-flow gasifier

• Published in: IOP conference series. Materials Science and Engineering 2018-05, Vol.355 (1), p.12022
• Main Authors: Zageris, G, Geza, V, Jakovics, A
• Format: Article
• Language: English
• Subjects: Aerodynamics; Air intakes; Ashes; Chemical reactions; Coal gasification; Computational fluid dynamics; Devolatilization; Entrainment; Gas flow; Mathematical models; Slagging
• ISSN: 1757-8981; 1757-899X
• DOI: 10.1088/1757-899X/355/1/012022

A CFD mathematical model for an entrained-flow gasifier is constructed - the model of an actual gasifier is rendered in 3D and appropriately meshed. Then, the turbulent gas flow in the gasifier is modeled with the realizable k-ε approach, taking devolatilization, combustion and coal gasification in account. Various such simulations are conducted, obtaining results for different air inlet positions and by tracking particles of varying sizes undergoing devolatilization and gasification. The model identifies potential problematic zones where most particles collide with the gasifier walls, indicating risk regions where ash deposits could most likely form. In conclusion, effects on the formation of an ash layer of air inlet positioning and particle size allowed in the main gasifier tank are discussed, and viable solutions such as radial inlet positioning for decreasing the amount of undesirable deposits are proposed. We also conclude that the particular chemical reactions that take place inside the gasifier play a significant role in determining how slagging occurs inside a gasifier.