Study On Decomposition Phosphogypsum In Circulating Fludized Bed And Fule Gas's Using

Phosphogypsum(PG) is a solid waste generated in the manufacture of phosphoric acid by wet process and is one of the greatest mass solid waste in chemical factory. Normally PG contains more than 90% CaSO₄·2H₂O which is a material for building industry. However, as PG also contains some harmful impurities, such as phosphate, fluoride and organic matters, if it is indirectly used. And PG brings severe pollution for atmosphere and ground water. Up-to-date, it has not made good use of and become social effects of pollution for environment pollution. State environmental protection administration of China determine the nature of PG act as a kind of hazardous waste in file (2006) 176．Achieve a new technology for a successful synthesis utilization of PG is possess commercial worthiness and practical signification for environmental security, resource's effective utilize and phosphorus fertilizer industry continuable development.The paper raise and study deoxidization and decomposition PG using yellow phosphorus tail gas ( the main ingredient is CO) and high sulfur coal. And this is the first new point in this paper. The paper raise and study PG's decomposition in Circulating Fludized Bed(CFB), and thus we can arrive high decomposition and desulfurization rate and high concentration sulfur dioxide. This is the second new point in this paper. We did cool experiments and mathematical simulation in cool experimental circulating fluidized bed device that was made of by myself. This is the third new point in this paper. We study selective catalyzation and deoxidization sulfur dioxide that comes form smoke. This is the fourth new point in this paper.The main results as follows:1,In this paper, some thermodynamic calculation and analysis for the possibility of deoxidization and decomposition PG was studied by using yellow phosphorus tail gas ( the main ingredient is CO) and high sulfur coal. Make sure the feasibility of deoxidization and decomposition PG using yellow phosphorus tail gas and high sulfur coal. The result show yellow phosphorus tail gas and high sulfur coal can reduce PG's decomposition temperature and deoxidization atmosphere is useful for PG's decomposition. The best temperature is 800～1200℃for deoxidization and decomposition PG.2,In this paper, kinetics parameters for PG and Nature gypsum(NG) decomposition was accepted by comparing PG with NG decomposition dynamics using TG-DTA curves. The results show: (1) impurities that lie in PG accelerate PG's decomposition, reduce PG's decomposition temperature, quicken PG's decomposition velocity; (2) with the advance of reaction temperature, it is more easy for PG's decomposition. And PG's decomposition accord with the model of form nucleus and grow up of gas-solid reactions's mechanism equations; (3) compare CaSO₄ with CaCO₅ decomposition technology, that show PG's decomposition is harder than CaCO₃ decomposition in reaction temperature,reaction atmosphere,reaction translation ratio,decomposition reaction mechanism.3,This paper indicates deoxidization and decomposition of PG using yellow phosphorus tail gas and high sulfur coal in small fixed-bed, with the hoist of reaction temperature, PG decomposition and desulfurization ratio is increased, reaction velocity is quickened and short deoxidize atmosphere is useful for enhancing the thickness of sulfur dioxide. We can conclude that it can advance the thickness of sulfur dioxide using high sulfur coal form the result.4,The paper studies cold experiments of PG's decomposition in CFB reaction device. The results of cold-flow model test indicate: (1) the pressure drop rises with increasing air quantity and solids quantity respectively, however, much more air quantity and solids quantity minish in the same height position; (2) the pressure drop rises with increasing solids quantity; (3) the average granule concentration minishes with increasing air quantity, and rises with increasing the granule quantity in the same level position; (4) the inhomogeneity of distribution granule concentration minishes with increasing air quantity, and rises with increasing the granule quantity in the same level position.5,The paper simulates and studies the experimental device by simulating and calculating business software of large scale fluid engineering(Fluent). Firstly, single bubble in the dense zone of fluidized bed was simulated, the second is the curve of the fluid particle, the third is solid space ratio distribution, the fourth is particles velocity vectorgraph and particles volume fraction, the fifth is grain press drop and rapid kinetic energy and rapid kinetic energy dissipation ration. The results shows the dynamical process of formation, movement upward, grown and eruption of bubble. The whole flow field was simulated and the results shows that it still can appear the different axial distribution of voidage due to different primary solids quantity, even if it has the same apparent velocity of air and circulating quantity of solids. They have a big inner loop in both the flow field which has rectangular section and entrance of the whole underside and the flow field which has cycloidal section and entrance of small center jet flow, it is useful for CFB reaction. Unilateral outlet of hearth top formatted the excursion of the maxium of granule concentration, of. granule velocity, of turbulent kinetic energy, of trubulent dissipation rate.6,The paper studies selective catalyzation and deoxidization sulfur dioxide that comes form smoke by using biomass pyrolysis gas, introduce the development of catalyzation desulfurization technology. Study catalyst's choice and preparation. And appraise catalyst's capability form three sides that are catalyst's active, selectivity and stability. The results show: (1) preparation methods have important infection for catalyst's active, and sol-gel > co-precipitation>impregnation; (2) Cu loading directly affect catalyst's active, selectivity and stability, different Cu loading has not obvious unlikeness in low temperature, but they have bigger difference in high temperature, and catalyst has the best effect when Cu loading capacity is 15%; (3) the best calcined temperature for catalyst is 750℃, in this condition catalyst can urge reaction gas's translation ration achieve the highest; (4) Fe,Co and Mo can improve Cu/Al₂O₃ capability, but Ni have no function when we change catalyst by using transition metal.