Aspen Plus Based Analysis Of Air Pollutants Emission And Energy Utilization In Cement Precalcining Kiln Process

The cement industry is a typical high resource consumption,high energy consumption and heavy pollution industry, whose fast development simultaneously causes severe resource, energy and environmental problems.Therefor, the implementation of cleaner production technologies in cement industries is necessary, which can achieve energy conservation, consumption reduction, pollutants decreasing and synergy.As the highly complex of the cement industry system, it is hard to estimate the new process arid alternatives via field investigation. In view of the above objectives and difficulties, the idea of cement industry process simulation is proposed,which aims to provide theoretical and data support for implementing proper cleaner production technologies in cement industries, by process analysis and modeled. Based on the mechanism analysis of the cement precalcining kiln system, this dissertation proposes a new method to simulate gas formation in the system. The cement precalcining kiln system process model is built using Aspen plus, and is used to study the air pollutants emission and utilization of alternative fuels of the whole system. The main contents of this dissertation include:(1)Simulation of air pollutants generation and alternative fuels plans in DD (Dual Combustion and Denitration) calciner. The DD calciner process model is built and verified. Then, for a concrete DD-calciner, the model is used to study the effects of the flow rate of coal and tertiary air on flue gas compositions and outlet temperature of the calciner. Meanwhile, the tertiary air consumption of different fuel plans is studied with this model.The results of case study indacate that the model is able to predict the outlet temperature and contents of flue gas components with a high level of.agreement with the values in the literature; compared with the mode which only uses coal as fuel, the plans only petcoke as fuel,50% coal and 50% petcoke as fuel,50% petcoke and 50% MBM as fuel need extra 41.5%,14.6% and 8.5% of the combustion air in the combustion process respectively, which can keep the good combustion environment.(2) Process simulation of the staging combustion technology in DD calciner. Based on the DD calciner process model, the tertiary air staging combustion model and the fuel staging combustion model is built up, and used to determain the staging combustion proportions which can meet specifications for the NOx and SO2 content. The results of case study indacate that the NOx, SO2 and CO can discharge within limit values when the proportion of air staging is controlled within the range of 57% to 65.52%(0.89