Modeling And Simulation Of Pitch Coke Combustion And Heat Transfer Processes In Rotary Kilns

As an important industrial raw material, pitch coke is produced by coal tar pitching on high temperature. In China, most pitch coke is produced using processed by delayed coking process, which makes the water, moisture and other impurities contents higher than the requirements of being the industrial raw materials. So the rotary kiln is needed to be calcined at a high temperature. In this processing, the kiln's wall heat preservation material is easy to break due to the over high of the temperature. This may even lead to an serious accident that influence the production. But the temperature of the material is hard to measure, so that scientific control is hardly possible.This thesis use a pitch coke calcination rotary kiln in a steel plant as research object to test the thermal process and the contents of the pitch coke using a model build up by the actual condition and the field test results. This thesis also build up three heat transfer model: heat transfer model, heat transfer fluid bed model and kiln gas model by discussing the energy coupling and heat transfer process. The temperature distribution, the gas flow field distribution and the distribution of each gas in the kiln is also calculated by using Fluent and Matlab coupled. The result of the calculated temperature distribution curves of kiln outer wall fits the actual working conditions well and proves the reliability of this method.For a results, a high temperature region is found both in the kiln head and the calcining zone. In the kiln zone, the high temperature is caused by the burning of the gas and dosen't cause a high temperature of the kiln wall. But in the calcining zone, the temperature can reach 1500? closely with the flue gas so it's easy to broken. This research suggest some about rotary kiln process control and improvement measures for improve the asphalt quality, prolong the service life and the energy saving.