Life Cycle Assessment Of Ceramic Tile Manufacturing:A Hybrid Data And Modeling Approach

With the sustained and rapid development of the social economy and the continuous improvement of people’s living standards,the building ceramic industry has also made massive progress.It is estimated that the capacity of China’s building ceramics will rise up to 1.0×10¹⁰ m² in 2020,of which the domestic market demand will reach9.0×10⁹ m² that is equivalent to 69%of the global ceramic tile consumption.Despite the huge economic benefits related to ceramic tiles in national economy and cannot be replaced effectively by other materials in a short time,the ceramic tile manufacturing process is known to have negative environmental impacts.Their manufacturing process consumes a large amount of energy and resources and involves production of the exhaust gas,wastewater,waste residue,dust,and other emissions that have a serious impact on the environment.Due to significance of the problem,more researchers have begun to pay attention to the environmental impact assessment of the ceramic tile manufacturing process.Despite the massive research being conducted in this area,a number of problems related to the environmental impact assessment of ceramic tiles are urgently needed to be addressed.Three major problem for the research are:1)According to the existing life cycle method,it is difficult to quantify and evaluate the ceramic tile manufacturing process level,which reduces the accuracy and reliability of evaluation;2)Although the traditional evaluation method driven by data can judge the degree of environmental impact,it cannot be reversed to mine the changes needed in ceramic tile manufacturing process,equipment used,and operation scheme that could provide reference and guidance for green manufacturing;3)Unclear data sources used for the environmental impact assessment of small and medium-sized ceramic enterprises are not capable of reflecting how change in production technology level,energy saving and emission reduction impact and the environmental changes at industrial and/or national levels.In order to perform a detailed assessment of the environmental impact of the ceramic tile manufacturing process and construct a method system to improve green energy conservation,a new method is proposed that makes use of hybrid production data and process models as the perspective,and carries out the following research on the basis of large-scale sampling and in-depth investigation:1)The life cycle assessment method driven by hybrid data and modeling which is based on the traditional life cycle assessment method is proposed to evaluate the environmental impacts of ceramic tile manufacturing process,that is,the energy consumption data of key processes are modeled and calculated by the theory of material conservation and energy conservation etc.,where the milling process uses the theory of pulverization and surface area to establish the energy consumption model,the spray drying and firing processes use the theory of material conservation and heat balance to establish heat balance models,and the polishing process uses the theory of kinetic and energy conservation to establish the energy consumption models;2)The proposed method is used to evaluate the environmental impact of the ceramic tile manufacturing process of a large ceramic enterprise ranking the top five in China’s ceramic industry.This method retains the state information of data acquisition,equipment parameters and environmental parameters during model calculation and has high accuracy,integrity,and consistency;3)Hotspot analysis,sensitivity analysis,and data quality analysis are applied to cross-validate the accuracy of the result,of which hotspot analysis mainly uses comparative analysis method to study the relative size of each life cycle stage and process,while sensitivity analysis mainly uses control variable method to study the degree of the impact of changes in each process on the final environmental indicators.CML2001 method built in Gabi software is used to evaluate the environmental impacts for the inventory data collected by the proposed life cycle assessment method.The results show that the environmental impact of each manufacturing stage is raw material preparation stage>manufacturing stage>>post-processing stage>storage stage,and the environmental impact of the mining and powdering processes in the raw material preparation stage is the most prominent,followed by the firing and drying processes in the production stage.The contribution rates of these four processes to all impact categories except ozone depletion potential exceeded 61%,of which the abiotic depletion potential fossil,global warming potential,and human toxicity potential reached 97.74%,95.34%,and 98.94%,respectively.Sensitivity analysis shows that all impact categories except ozone depletion potential and human toxicity potential are sensitive to the mining and powdering processes,that is,reducing the energy consumption of these two processes will effectively improve these environmental impact categories,such as reducing energy consumption in the powdering process by 10%will produce 5.484%MJ,2.869%SO₂equivalent,3.953%phosphate equivalent,4.84%CO₂ equivalent,and 2.499%ethene equivalent for abiotic depletion potential fossil,acidification potential,eutrophication potential,global warming potential,and photochemical ozone creation potential,respectively.These results show variation from previous researches performed on small and medium-sized ceramic enterprises that determined firing and drying processes as the main contributors to the environmental impact.Based on the results of the field investigation,inventory analysis,impact potential and sensitivity analysis,it can be concluded that three important aspects that need to be further improved in the ceramic tile manufacturing are the equipment upgrading in the mining process,the mode conversion in the powdering process and the waste heat recovery and utilization in the firing process.This paper has some innovations in research methods and applications,that include introduction of a new method for life cycle assessment that is driven by hybrid data and modeling,and the first-time application of the life cycle assessment method for ceramic tile manufacturing process in a large-scale ceramic enterprise.The research addresses the limitations of the traditional life cycle assessment method and provides new method with various applications for other researchers to study the life cycle assessment method.More accurate evaluation results from new method of the ceramic tile manufacturing process in a large-scale ceramic enterprise can better represent the production technology level,energy saving and emission reduction status of China’s ceramic industry,will hence,help the relevant government departments to formulate more precise energy conservation limits,emission reduction targets,environmental protection laws and regulations.Furthermore,the research method and results can be combined with cost modeling tools and help decision making for ceramic enterprises to carry out energy conservation and emission reduction activities at the optimal costs.