Life Cycle Assessment Of Co-processing Industrial Waste In Cement Kiln

Our cement production increased in 2013 compared to 2012 by 9.8%, and cement production capacity reached 3 billion tons per year at the end of 2013.Due to manufacturing technique, large amount of SO2 and NOx are discharged into the environment. What’s more, excessive non-renewable energy and resources are consumed during the production processes. On the other hand, the amount of industrial waste is increasing. Chinese industrial waste generated in 2013 was about 3.23 billion tons, of which the number is about 46 million tons of hazardous waste. In this context, the cement kiln co-processing industrial waste technology was proposed. It refers to the use of the modern cement production technology in cement industry, which can dispose some industrial waste as alternative energy and raw materials to realise the resource utilization, doesn’t create additional environmental impact. The environmental impact of co-processing with waste clay, spent catalysts, contaminated soil and other industrial waste in cement kilns were assessed by using life cycle assessment (LCA). A life cycle inventory including input and output process of cement production was established based on inventory analysis. Gabi5.0 software was used to model and calculate the original data to obtain the corresponding environmental impact potentials, which were compared conventional cement process with co-processing cement process on global warming potential, resource depletion potential and human toxicity potential.(1) Method of life cycle assessment was applied to evaluate the resource depletion and environmental impactpotential of a cement plant employing cement kiln co-processing industrial waste technology. Scope of the research was identified including upstream and downstream process, and life cycle inventory was established based on five production process during cement production. According to the life cycle inventory, researches for conventional and co-processing were conducted.(2) The data was calculated by using the CML2001-Nov.2010 model and achieved finally results obtains nine types of environmental impacts, such asacidizing calculation, eutrophication and global warming potential values and so on.The results showed that the environmental impact values of conventional and co-processing cement process for per functional unit of cement production were 5.78E-11 and 5.61E-11 respectively. Compared with conventional production process, the lifecycle environmental impact potential of co-processing was reduced by a factor of 2.94%. (3) global warming potential and human toxicity potential make the greatest contribution to environmental impacts in cement production, whose environmental impact potentials of co-processing were decreased by 0.80% and 1.80% respectively, the environmental impact potential of co-processing on resource depletion was decreased by 11.1%; from the view of a whole lifecycle prospect of cement production, clinker calcination ranked the first place in causing environmental impacts, compared with the conventional production process, the reduction rate of co-processing was 8.0%. Co-processing has a better environmental performance than conventional production.