Optimizing Dry Sorbent Injection Performance Using Chemistry-Based CFD Modeling

摘要

There have been many dry sorbent injection (DSI) systems installed to remove acid gases from combustion flue gas for MATS compliance. Utility owners are now looking to optimize these systems to reduce costs for long term operation. In this paper, an advanced chemical kinetic model is developed as a cost-effective tool to evaluate and optimize DSI systems instead of costly trials. The chemistry involves mechanisms of sorbent calcination, sintering, and simultaneous reactions with SO_2 and HCl, which allows for predicting SO_2/HCl reduction by trona with certain properties. Further, coupling this chemistry sub-model into a CFD code of flue gas duct modeling allows for optimizing DSI systems through different injection designs. The model is first validated against a full-scale DSI trial in a coal-fired utility boiler, and then used to optimize the existing injection systems based on predicted performance. The paper provides details about the model development, validations and injection optimization.