The Research Of CDC Calciner Improvement And Numerical Modeling Analysis On Pulverized Coal Combustion In The Calciner

Calciner, as the kernel equipment of the dry precalcining kiln system, is a multiphase reactor, in which some physical and chemical process, such as gas-solid heat transfer,pulverized coal combustion,carbonate disassembly and so on, take place. The performance of the calciner directly influences the stability and capability of the the dry precalcining kiln system. Though it has been studied by means of modern theoretics, but it is still hard to understand the combustion mechanism in the calciner completely. Meanwhile, the coal variety and reaction conditions in the calciner affect the combustion of the pulverized coal in it. All of these will impact rationality of design and the performance of the calciner.Based on the theory of gas-solid momentum, heat and mass transfer, as well as chemical reactions in calciner, this paper improves the CDC calciner in Wenshan cement plant and measures its kinds of capability by cold model testing. It indicates that the 3D flow of the improved calciner is more logical than before, it's resistance loss descend greatly, the materiel in calciner could blend more fully with gas, the materiel's available retention time has be extended, the retention time changes from 14.74s (clinker production 1200T/D) to 16.46s (clinker production 1450T/D). In conclusion, the pulverized coal can burn more adequately in calciner,the burn-out ratio also would be higher than before.On base of transform theory and the macro-general rules of coal combustion, meanwhile according as some theories and experience formulas, this paper builds a comparatively perfect combustion model of calciner and programs it into a calculate software. When changing the correlative industrial parameters, the burn-out ratio,combustion velocity,decomposition degree of the calciner and so on, can be figure out quickly.It indicates by theoretical analysis and calculations that the pulverized coal combustion in the calciner has two conditions: one is controlled by dynamical reaction, the other is controlled by dynamical reaction and mass diffusion together. For most calciners, their index of combustion condition Fb all are lower than -2.3, It means that the pulverized coal combustion in calciners is mostly decided by reactivity of coal. On the same temperature, because of big reactivity the wood coal's burning rate is higher than other kinds of coals', and can more quickly entering the zones controlled by dynamical reaction and diffusion together under a rather lower temperature. For any coals, it's burning rate increases when the temperature rises. In the zones controlled by dynamical reaction , the coals'burning rate can...