| With the rapid development of modern industry and the big change of people’s lifestyle in China, a large number of industrial waste and municipal solid waste and other hazardous waste is resulting rapidly. At present, it is a very effective way to reduce environment pollution and to recycle resources by using industrial furnaces especially the cement kilns to co-processing solid hazardous waste, including the harmful organisms. Therefore, studying the engineering technology, environmental risk management and management technology, has very important applications and the reference value.Firstly, benzene and perchlorethylene were selectedand as two kinds of typical hazardous organicsl for pyrolysis experiments in high-temperature furnace in order to study the different decomposition characteristics at different temperatures. The analysis showed that the different class of organism has different dynamic character. The activation energy of benzene E=122.98KJ/mol, the pre-exponential factor A=1085.14s-1and the dynamic equation is a=1-exp (-1085.14exp (-15034.8/T) t). The activation energy of chloroethylene E=35KJ/mol, the pre-exponential factor A=7.724s-1and the dynamic equation is a=1-exp (-7.72exp (-4288/T) t).Through analysis of pyrolysis dynamic experiment results, a theoretical basis can be provided for the decomposition of organisms in a cement kiln.Next, we used the numerical simulation software Fluent to found the model of cement rotary kiln which was currently promoted in dry kiln production techniques. Thought the model, we conducted the numerical simulation of combustion and co-processing process in rotary kilns. According to the cement rotary kiln with a four-channel coal burner, the physical model is estabilished. The temperature inside reached up to2000K,the temperature distribution is close to the actual working condition. Then we analyzed the the distribution rules of vilocity field, the combustion temperature distribution and the components concentration field such as O2, CO and CO2. The analysis can provide a reference for co-processing harmful organisms.Finally, we carried out the numerical simulation of co-processing harmful organisms by adding organic matter to the cement rotary kiln model. And the analysis was been used to find the different influence between different dosing methods and different dosage through the results of the simulation. We respectively addde benzene through outside air duct and inside air duct of the burner. The result showed that the flame position,the distribution of temperature field and the composition of the gas distribution like O2,CO and CO2in the kiln changes with the difference of dosing methods. When the mass ratio of coal-benzene is100:1, the position of the flame and the high temperature filed is closer to the kiln head about2-3m, the total temperature is higher but the outlet temperature becomes lower than the no-addition condition. By changing the type of the outer duct dosage we found when the adding mass ratio of adding the ratio of coal-benzene reached10:1, the combustion process would change in a big degree; when adding mass ratio of coal-benzene is less than20:1, nd we can adjust the actual production conditions to ensure the normal production processo f the combustion. The benzene completely decomposed,which met the requirement of engineering and technology. Through simulation results obtained for the parameters, we can provide a valuable reference for the actual application of co-processing engineering. |
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