Continuous Sorbent Reactions in a High-Temperature Fabric Filter Following Convective Pass Ca(OH)2 Injection for SO2 Removal.
A specially designed two-stage reactor was used to study solid sorbent reactions in the filtration stage of a high-temperature fabric which follow convective pass Ca(OH)2 injection. Solid conversions during the progress of the sorbent reactions were thoroughly analyzed. It was found that, unlike the sorbent reactions in the injection stage, which proceed extremely fast with strong carbonation under high temperatures, the subsequent sorbent reactions in the filtration stage are much slower and residual sorbent is mainly utilized in removing sulfur dioxide (SO2). Two major reaction pathways are discovered in the filtration stage. The first route is through the decomposition of residual calcium hydroxide (Ca(OH)2), which is critical in inducing further sorbent reactions when there is sufficient residual sorbent. The second route is the sulfation of the carbonation product, calcium carbonate (CaCO3), which may become the principal reaction to remove SO2 after the residual sorbent is consumed. The con-vective pass and the fabric filter are found to be equally important reaction sites in the combined process of convec-tive pass sorbent injection with high-temperature filtration. The overall SO2 removal efficiency of the system is affected by both the sorbent injection and filtration conditions.
Kinetic Studies on the Medium Temperature Ca(OH)2 Sorbent Injection FGD Process
Recent progress in dry sorbent injection flue gas desulfurization (FGD) has resulted in a medium-temperature sorbent injection process. Compared to conventional furnace injection, this new process exhibits equivalent SO2 removal performance at a much lower operation temperature, allowing the injection point to move to a lower temperature region downstream of a furnace.
Thermal stability of the magnesian and calcareous compounds for desulfurization processes
Abstract Relationships are presented for predicting the decomposition heats and dissociation pressures of hydroxide, carbonate, sulfite and sulfate of magnesium and calcium at different temperatures. The proposed equations have been developed on the basis of thermodynamic data and experimental findings available in the literature. The results are also expressed in graphical form and are discussed from the standpoint of removal of sulfur dioxide from flue gas at different temperatures Experimental results are also presented of the controlled decompositions of the compounds carried out in a thermogravimetric analyzer. The stable temperature ranges of the compounds were determined.