Analysis Of Energy Comsuption Of Alumina Manufacturing Process And Research On Energy Saving Technology For Procedure Based On D-e-p Model

As the process of industrialization of human society speeds up, energy and environmental issues are becoming more urgent to resolve for the whole world. Energy consumption of industrial sectors, especially metallurgical industry is obviously prominent. Since alumina refinery is the backbone of China’s metallurgical industry, to research the energy utilization in alumina refinery process and tap the potential of energy saving for the enterprises as much as possible are of great significance to improving the products’international competitiveness and maintaining China’s sustainable development in economy.This paper presented a preliminary energy consumption analysis of an alumina refinery process with Bayer-Sinter combination method based on a large number of raw data of this process and the e-p method which has been widely used in ferrous metallurgy. The result shows that evaporation, slurry sintering, lime calcining and tube digestion are the mainly intensive-energy consumption sub processes. Their direct and indirect energy consumptions have remarkable impact on that of the enterprise.The exergy analysis model of the Bayer-Sinter combination process was established in the form of the grey box model and subsequently the energy consumption and effective utilization degree of all sub processes were evaluated. The results show that the average exergy efficiencies of sinter digestion and desilication are the highest, which are in excess of80%. The extrinsic exergy losses in slurry sintering and lime calcining are large and can be recovered to a considerable extent. Thus the two sub processes have large energy saving potentials.The d-e-p analysis model of an enterprise’s system energy consumption was put forward and established at the first time on basis of exergy analysis theory, and then applied to calculate and analyze the energy consumption, exergy losses and their distribution in the alumina refinery process. The results indicate that there are mainly two factors influences the supply exergy of all sub processes:the direct exergy consumptions affected by the energy consumption levels of sub processes and the indirect exergy consumptions affected by alumina-process product-ratios. The factor influences the exergy losses in sub processes primarily include two items:the direct exergy losses and the indirect exergy losses. The impact of product-ratios on the comprehensive energy consumptions is significant. The energy consumptions and supply exergies of several sub processes reduced, however, the related comprehensive energy consumptions increased after taking the product-ratios into account. Although the energy consumptions of tube digestion, sinter digestion and desilication reduced, the exergy losses didn’t decline accordingly but raised.On the basis of the analysis using d-e-p model, the sub processes of lime calcining and slurry sintering were optimized and improved according to the distribution of exergy loss, which brought significant energy saving. The effect on the product ratio brought by the change of Al-Si ratio was analyzed, and the change of the product ratio and indirect energy saving were forecasted when the Al-Si ratio increased to10. Then suggestions about energy management were given in order to decrease the energy consumption.To conduct a comprehensive study of energy saving in alumina refinery process from the quantity and quality of energy can contribute to tapping the potential of energy saving for the enterprises systematically and has important theoretical and practical significance to energy saving and consumption reducing of the alumina industry sector.