(465b) A CFD Model for Hot Gas Desulfurization Process

Coal based Integrated Gasification Combined Cycle (IGCC) plants have the advantage of improved power generation efficiency, high power to heat ratio for cogeneration and better environmental performance, particularly in the area of capturing pollutants such as hydrogen sulfide, carbon dioxide and mercury from the flue gas. Hot gas desulfurization technology is a strong contender for the sulfur removal process, prior to fuel gas combustion. The process involves the transport of fuel gas through a reactor containing solid sorbent that absorbs sulfur. Of the many advantages it offers are its ability to operate at higher pressures and temperatures closer to the gasifier and higher process efficiency. Moreover, the sulfur laden sorbent can later be regenerated back to its original state. In this work, a Computational Fluid Dynamic (CFD) model has been developed to simulate the desulfurization and regeneration of zinc oxide sorbent pellets. The CFD model, which is an extension of the variable grain model, accounts for sintering of grains and pore closure in the pellets. The CFD model is validated against experimental data taken at National Energy Technology Laboratory (NETL). The model is then used to simulate the desulfurization process in a 50 MW absorption transport reactor.