Research On Domestic Waste Incineration Strategy Based On Carbon Emission Reduction And Benefit Analysis

Domestic waste treatment,especially waste incineration,directly or indirectly releases large amounts of CO2,CH4 and N2O,which are considered to be one of the main sources of greenhouse gas emissions(GHG).Given the variable characteristics of domestic waste,and the complexity of the process in domestic waste incineration plants.It is difficult to meet the calculation of carbon emissions within the accounting scope by simply using the common formulas and emission factors in the IPCC guidelines(IPCC 2006 Revised Guidelines for National Greenhouse Gas Inventories 2019).In addition,the IPCC guidelines only consider carbon emissions from fossil carbon in the treatment process,however,it is estimated that the carbon emissions caused by biochar are significant,so the carbon emissions in this study are all carbon emissions rather than fossil carbon emissions.Therefore,based on the IPCC guidelines,this study uses the material balance method and refers to the chemical equations and empirical formulas in the biochemical reaction process of leachate treatment to determine the full CO2,CH4 and N2O emission calculations during the operation of a domestic waste incineration power plant,and analyses the various cost benefits of the operation process.The carbon emission estimation is carried out with a typical domestic waste incineration power plant as an example,and a cost-benefit analysis is presented.In addition,combined with the energy consumption of typical domestic waste incineration power plants and the analysis of the mass-energy balance of incinerators,two domestic waste incineration strategies were proposed under the condition of waste classification,and the carbon emissions and cost-effectiveness of mixed incineration were analyzed and compared.Finally,the development and application of carbon emission accounting software for domestic waste incineration power plants was carried out.The main findings are as follows:(1)Net greenhouse gas emissions from a typical domestic waste incineration plant are 614.38kgCO2-eq/tMSW,of which total emissions are 903,88kgCO2-eq/tMSW,direct emissions are 837.02kgCO2-eq/tMS W,indirect emissions are 49.07kgCO2-eq/tMSW,other emissions are 17.78 kgCO2-eq/tMSW,and carbon sinks of-289.50kgCO2-eq/tMSW.Waste incineration in direct emissions accounts for 83.25%of the total emissions and is the focus of carbon emission reduction.The electricity consumption of the M&E operation process is 48.79kWh/tMSW,and the leachate treatment station only accounts for 11.32%to 20.24%,of which the anaerobic link accounts for 5.22%of the leachate treatment station,and the biogas produced is not recovered.In addition,according to the mass-energy balance calculation of the waste incinerator,the combustion temperature of the waste incinerator can only meet the minimum requirement of 850℃ with the addition of auxiliary fuels,and the waste characteristics fluctuate with the seasons and other reasons,and the calorific value is not stable.Accordingly,separation of food waste is considered to reduce the amount of waste incinerated and to increase the carbon sink.In addition to the current situation of mixed waste incineration,two waste treatment strategies are proposed:(i)separate collection+anaerobic co-digestion of food waste with leachate(low solids content)+co-incineration of residual waste with sludge(strategy 1);(ii)separate collection+anaerobic digestion of food waste alone(high solids content)+co-anaerobic digestion of digestate and leachate+co-incineration of residual waste with sludge(strategy 2).(2)The two proposed waste treatment strategies can significantly reduce greenhouse gas emissions and increase net waste treatment benefits.The net GHG emissions of Strategy 1 and Strategy 2 were measured to be 398.43 kgCO2-eq/tMSW and 380.39 kgCO2-eq/tMSW,which are 35.17%and 38.11%lower respectively compared to the status quo of mixed incineration.The direct carbon emissions decreased by 28.66%and 19.78%respectively,which is mainly due to the lower mass entering the waste incinerator;indirect carbon emissions and other carbon emissions both varied in equal proportion to the corresponding treatment volumes;the carbon sink of strategy 1 decreased by 12.86%to-252.28 kgCO2-eq/tMSW and strategy 2 increased by 26.83%to-367.19 kgCO2-eq/tMSW,mainly due to the lower quality of waste entering the incinerator and the lower electricity production per tonne of(treated)waste,however Strategy 2 generates a large amount of carbon sink due to biogas,grease recovery to make up for this shortfall.In terms of cost effectiveness,the net benefit of the mixed incineration status quo is 226.60 yuan/tMSW,compared to 281.31 yuan/tMSW and 395.36 yuan/tMSW for strategy 1 and strategy 2 respectively,an improvement of 20.69%and 74.47%respectively.(3)Based on the established carbon emission model for domestic waste incineration power plants,the development and application of a carbon emission accounting software for domestic waste incineration power plants has been completed.The direct,indirect,other,sink and net greenhouse gas emissions for a single day of a domestic waste incineration plant can be directly calculated by entering the quantity characteristics of domestic waste,leachate,various types of consumption,and the relevant process parameters.A user-friendly tool for accounting for carbon emissions from domestic waste-to-energy plants.