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Author: search.filters.author.Singh, Shamsher BahadurSubject: search.filters.subject.Life cycle assessment (LCA)

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    Probabilistic life cycle assessment of ash-based sintered lightweight aggregates manufactured with producer gas and coal-operated thermal power
    (Springer, 2025-09) Singh, Shamsher Bahadur; Barai, Sudhir Kumar
    The infrastructure growth in the world is expected to result in huge requirement of 12.5 billion tonnes of coarse aggregates in 2050. The utilization of artificial aggregates can pave a feasible pathway for tackling the issue of scarcity of natural aggregates. Life cycle assessment (LCA) is an environment management tool, which has been used for the large-scale acceptability of sintered flyash lightweight aggregates (SFLA) in the construction fraternity. The low quality of data inputs for LCA study induces bias and increase in uncertainty of evaluated impacts. In the current study, a probabilistic LCA framework has been developed for assessing the environmental impacts from the manufacturing of SFLA. The uncertainty distribution range in each of the input variables was identified and introduced in the model with the help of random numbers. In this study, uncertainty analysis is also carried out using Monte Carlo Simulation for the comparative analysis of baseline scheme with three alternative schemes of SFLA manufacturing process. Finally, the sensitivity analysis (SA) was also undertaken for studying the robustness of LCA model outputs. The global warming potential (GWP) for the baseline scenario is 198.6 kg CO2 eq. per t of SFLA. Three alternative schemes were proposed for which comparative impact assessment is carried out, which highlighted the GWP impacts reduces to 166.7 kg CO2 eq. per t of SFLA (16% lower), 142.6 kg CO2 eq. per t of SFLA (28% lower) and 123.4 kg CO2 eq. per t of SFLA (38% lower) for first, second and third alternative schemes respectively as compared to the baseline scheme. Sintering process is contributing highest to impact mainly due to emissions from combustion of coal present in raw mix, CO2 emissions from electricity consumed during the process and CO2 generated from producer gas production which is used for thermal energy in sintering process. The results of probabilistic LCA study show that there are significant variations in the coefficient of variation across the various unit processes and across the four impact categories.
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    Life cycle assessment of artificial sintered flyash lightweight aggregate produced in India using OFF gas and coal based thermal power
    (Springer, 2025-02) Singh, Shamsher Bahadur; Barai, Sudhir Kumar
    The potential environmental impacts associated with production of sintered flyash lightweight aggregate (SFA) needs comparison with natural aggregates (NA) which can directly help in the selection of sustainable materials. In the previously reported research, the impact of SFA manufacturing using off gas as thermal energy source is not assessed and site-specific data is also not available. Therefore, this study covers the life cycle assessment (LCA) of SFA production in India using coal based thermal power and off gas as source of thermal energy. In the present LCA study, all the inputs like raw materials, heat, electricity and outputs like product and emissions associated with production of SFA were inventoried, to evaluate the life cycle environmental impacts of SFA. The main purpose of this LCA study is to evaluate the alternative scenarios of making the SFA environment friendly by use of renewable energy and green fuels. Within the SFA manufacturing plant, a number of discrete unit processes were identified like raw material handling & mixing, palletization, sintering and screening and input–output analysis is undertaken for each unit process (including electricity and transportation). The impacts associated with SFA are compared with NA in terms of Global Warming Potential, Acidification Potential, Eutrophication Potential and Abiotic Depletion Potential. In this study, it was found that the environmental impacts associated with production of SFA are 55 to 90% higher as compared to NA. The Global Warming Potential impacts associated with 1 tonne of SFA are 83% higher as compared to 1.5 tonne of NA. Similarly, in terms of acidification potential and eutrophication potential, SFA are having 55% and 90% higher impacts as compared to natural aggregate respectively. The three alternative scenarios are developed based on contribution analysis. The alternative scenarios evaluated in this study are (a) electricity consumption based on 100% Solar power (b) biomass based OFF gas and electricity from coal based thermal power plant and (c) biomass based OFF gas and electricity from Grid. The study concludes that heat consumption in sintering process and electricity consumption in various unit processes are the main contributors for various environmental impacts in production process of SFA. The alternative routes like usage of biomass based OFF gas and grid-based electricity will help in reduction of environmental impacts associated with production of SFA and make it comparable with natural aggregates.