Study On Integrated Catalysis For Sulfur Retention And Coal Combustion

In this paper, a series of integrated additives that have bifunction of catalysis and sulfur retention during coal combustion was developed and the mechanisms of integrated catalysis for sulfur retention and coal combustion were discussed. Based on the obtained results, a novel integrated additive composed of crude minerals and industrial wastes was developed and commercialized on a 130 ton/hr pulverised coal boiler in a power plant.The formulations for calculation of slag, flue gas compositions and heat efficiency of coal boiler in the presence of sulfur sorbents were modified. The influences on heat efficiency of boiler using integrated additives of catalysis and sulfur retention were discussed in detail regarding three different kinds of boilers of chain-grate stocker, pulverized boiler and fluidized bed boiler. And these results composed the foundation of the utilization of integrated catalysis for sulfur retention and coal combustion.The influences on sulfation reaction of CaO of promoters Na2CO3, MgO and Fe2O3 in integrated additives were investigated by the experiments of thermogravimetry analysis and high temperature combustion sulfation. Synergistic effect of multi-component promoters was put forward and the catalytic sulfation of different metallic compound promoters for different boilers was discussed. The kinetic parameters of CaO sulfation reaction with and without additives doped were calculated using the Particle Model. The results show that the catalytic promoter Fe2O3 in additive catalyzes the reaction of SO2 to SO3 and accelerates the sulfation reaction rate of CaO both for chemical reaction control region and diffusion control region. And in the diffusion control region of CaO sulfation reaction, the existing of Fe2O3 alleviates the aggregation of CaSO4 so that weaken the pore closure effect of CaO sulfation reaction.