Numerical simulation on adsorbent injection system for mercury removal from coal-fired flue gas

Optimizing the injection system significantly reduces the cost of adsorbent injection technology for mercury removal from coal-fired flue gas. In this work, the effects of three common injection system layouts, namely single-sided four-way pipe (SFP), quadtree (QT), and long to short (L-S), on adsorbent particle concentration, mercury concentration, and mercury removal efficiency were systematically investigated by simulation calculation. It shows adsorbent coverage, and particle concentration standard deviation coefficient at the initial injection satisfies SFP > QT > L-S. The number of nozzle and injection directions affect the distribution of adsorbent particle concentration. The apparent mercury removal occurs within 2 s after adsorbent injection. The SFP arrangement has the best average coverage rate of adsorbent (86.86%), average standard deviation coefficient (2.40), and mercury removal efficiency (60.12%). The coupling degree between particle concentration and flue gas mercury concentration field is essential in determining mercury removal performance. & COPY; 2023 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.

Automated summary

Optimizing the injection system significantly reduces the cost of mercury removal from coal-fired flue gas using adsorbent injection technology. Three common injection system layouts (SFP, QT, and L-S) were systematically investigated to understand their effects on adsorbent and mercury concentration, as well as mercury removal efficiency. The results showed that SFP arrangement had the best performance in terms of adsorbent coverage, average standard deviation coefficient, and mercury removal efficiency. The coupling between particle concentration and flue gas mercury concentration field is crucial for achieving high mercury removal performance.