Comparison of In-Furnace Dry Sorbent Injection Full-Scale Tests With Laboratory-Scale Sulfation Correlations

摘要

In an effort to limit SO_2 emissions to the current EU air pollutant regulations, flue gas desulfurization tests were performed with in-furnace dry sorbent, Ca(OH)_2, injection technology in the Spanish coal power station "Litoral." The measured SO_2 removals―19.5% using a Ca-S ratio of 3 for a coal containing 0.53% of sulfur, and 26.4% with Ca/S=1. 75 for a coal with 0.73% of sulfur―were lower than predicted through a 1-D model. Hence, it was thought that a 3-D computational fluid dynamics (CFD) simulation of the injection of sorbent particles would assist in understanding this complex process. After the turbulent velocity and temperature fields in the furnace were modeled, representative sorbent particles were injected, obtaining the temperature and SO_2 concentrations encountered by the particles as a function of time. These data were the input to the global sulfur capture model used to simultaneously analyze calcination, sintering and sulfation. The simulation compared well with the data measured in the power station, thus verifying laboratory-scale correlations. The main conclusion is that the first temperatures encountered by the particles―in addition to the mean diameter, the sulfur content and the Ca/S ratio―control the sulfur retention. Furthermore, it is extremely difficult to accurately predict these temperatures without a CFD simulation. Low retentions were due to low sulfur concentration, the high mean diameter of the panicles, and the position of the injection nozzles.