| Coal is the major primary energy in China, and about 50% coal consumption is used in the power generation. But the power generation efficiency is low in traditional thermal power generation, and the problem of environmental pollution is serious. The integrated gasification combined cycle (IGCC) combines the coal gasification and the combined cycle efficiency together, and it is a typical high efficient and clean coal technology. Radiant syngas cooler is a very important equipment of the sensible heat recovery system in the IGCC system. The sensible heat of the high temperature syngas, which comes from the gasifier, is recovered by the radiant syngas cooler, and the overall system efficiency of electricity generation of the IGCC system can increase about 2 to 4%.The working conditions of the radiant syngas cooler is very poor, the high temperature and high pressure syngas carries a lot of ash and slag spray in the radiant syngas cooler. The water wall of the radiation syngas cooler is scoured seriously by the syngas and the ash, the mechanical wear of the water wall is severely, sometimes, it will effect the safe operation of the IGCC system. Therefore, investigate the temperature field, flow field simulation and analysis, the gas-solid two-phase flow of radiant syngas cooler is very important for designing the separation device and predicting the wear conditions.In this paper, Base on the support of the "National 863 Plan", a syngas cooler with double water wall is considered in a middle-class test system. In order to obtain the inside the gas-solid flow, temperature distribution and the particle trajectory ultimately, the k-e model and the Euler-Lagrangian stochastic model is employed in the gas,gas-solid particle flow simulation inside the radiant syngas cooler. On this basis, combined with design conditions of the pilot experiment, based on the principle of inertial separation of solid particles and solid particles deposition, on the premise of the best position for the separation of solid particles confirmed, a solid radial particle separation devices made of multi-layer structure is designed with orthogonal analysis method , after the relevant numerical simulation with the help of Fluent software finished , a in-depth study upon the separation of the separation device is executed, and carry out the influence of the relevant parameters upon the separation of the separation device, which are separation of ring angle, space ratio, the ratio of cover, in order to provide a theoretical basis for the design for different case of separation device design parameters. The results showed that: when the ring angle is equal to 50°, space ratio is equal to 0.5, and the ratio of cover is equal to 5%, the radial separation of the highest separation efficiency of the device.Then, based on the flow field and article trajectory simulation within radiant syngas cooler , programming, statistics of particle collisions on the inner and outer water wall, identify the area where particle collision probably occurred in radiant syngas cooler, and for the type area, statistics of 30 ~ 100μm different size of the number of solid particles collisions in the region, and calculated according to its particle trajectory angle, and then by Hamed semi-empirical formula generated from wear particles on the carbon steel to calculate the different particles on the wall wear conditions, while the predicted value of wall thinning caused by mechanical wear on the standard conditions is given in the regional area. Those provide an important theoretical basis for the actual engineering design for the optimization of the boiler structure and special preventive treatment of the relevant region. The results show that the last paragraph of radiant syngas cooler wall wear is serious , the most severe area can be worn year 3.3 mm. |
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