Numerical Simulation And Experimental Research Of Pre-calciner Heat Transfer And Flow Characteristics In Cement Production

The new dry cement production technology is the most advanced technology of cement industry. In recent years, the new dry cement production technology matures, and developes toward serialization, large-scale and ecological. Pre-heater system is the core part of new dry cement production process, and the pre-calciner is one of the key equipments in this system. This article uses the method of combining experimental measurement and numerical simulation, and has carried on the research of heat transfer and flow characteristics of pre-calciner of 2000t/d cement production line in Shanshui Group. Main work and results are as follows:1-, Decorate monitoring and sampling points reasonably combined with field condition, and then measure the physical quantities in the actual working condition and get the required data.2^ Using Pro/ENGINEER software to build geometric model of pre-calciner, and mapped meshing the geometric model. Selection of several groups of different number of grid, test grid independence, and determine the optimal grid number of numerical simulation.3-. Using FLUENT software, choose standard k-s model to complete the numerical simulation of gas phase flow field in pre-calciner,and get the velocity distribution cloud image, the velocity vector diagram and system flow diagram. The results show that:gas rises spirally, and there are Several toroidal vortex flow and obvious vortex phenomenon in pre-calciner, but the velocity distribution in the furnace is not symmetrical.4, Based on the gas phase flow field simulation, using discrete phase model, complete the numerical simulation of gas-solid two phase flow field in pre-calciner, and get the velocity distribution nephogram, raw particles trajectory graph and coal particles trajectory graph. Results show that:the velocity distribution is similar to the gas phase flow field, raw and coal particles diffuse in good condition in pre-calciner, almost full of the whole furnace body space, the longest residence time of raw material particles in the furnace is 11.9 s.5n Using non premixed combustion model, complete the numerical simulation of pulverized coal combustion process in pre-calciner, and get the velocity distribution, temperature distribution, various components concentration distribution and particle trajectories. Results show that:the velocity distribution of hot flow field is similar to the cold flow field, but the overall speed is higher than the cold flow field, also exists the phenomenon of asymmetry of velocity distribution; the outlet temperature is too high, the temperature of near wall area in the lower mixing chamber is too high; concentration distribution of O2, CO2, CO in the furnace is reasonable.;coal particles disperse in good condition.6、According to the results of numerical simulation, put forward the corresponding improvement scheme of pre-calciner of this production line, and complete the numerical simulation of improved furnace model. Compared with before improvement, velocity field and temperature field are all improved.