典型露天煤矿全生命周期碳排放核算及其区域环境影响

Full lifecycle carbon emissions accounting and regional environmental impact assessment of typical open-pit coal mines

  • 摘要: 碳排放核算是减污降碳协同增效目标中的重要环节,煤炭行业是碳减排的重点领域之一。文中以典型露天煤矿为研究对象,构建煤炭产品全生命周期的碳排放核算模型,量化矿区各生产环节的碳排放清单,评估露天矿区碳排放对区域环境的影响。根据全生命周期理论,将煤矿生产企业的碳排放核算环节分为煤炭开采、煤炭洗选、运输储存、使用消费以及其他步骤,在核算过程中总结归类碳排放来源。其中,直接碳排放包括燃料燃烧CO2排放以及CH4逸散排放;间接碳排放包括净购入电力及水力消耗碳排放。结果表明:露天煤矿年碳排放量为153 817 8.60 tCO2e,每生产1 t原煤排放二氧化碳(CO2)当量数为0.05 tCO2e,露天煤矿的碳排放主要来自煤炭开采和矿后活动导致的甲烷(CH4)逸散排放(占比79.92%)。除此之外,化石燃料燃烧的碳排放占总碳排放量的13.71%;电力和水力碳排放占比最少(6.37%)。我国近10 a露天煤矿温室气体年平均碳排放量为3.24 (± 0.77) × 107 tCO2e,相当于5.23 (± 1.24) × 108颗树木1 a的固碳量,或113.83 (± 27.00) 万公顷杨树林1 a的固碳量。同时,按照目前的开采方法和工艺,全国每年会产生超过23亿元的额外经济支出,并且随着露天煤矿开采量的增加而逐年增大。因此,减少煤炭露天开采过程中的碳排放极为重要,尤其需进一步关注逸散环节。研究结果对煤炭行业构建规范的碳排放核算体系、评估其区域环境影响具有重要的启示意义。

     

    Abstract: Carbon emission accounting is an indispensable and important part of the synergistic goal of pollution reduction and carbon reduction, and the coal industry is one of the key areas of carbon emission reduction. In this study, a typical open-pit coal mine was taken as the research object, a carbon emission accounting model for the whole life cycle of coal products was constructed, the carbon emission inventory of each production link in the mining area was quantified, and the impact of carbon emissions in the open-pit mining area on the regional environment was evaluated. According to the life cycle assessment (LCA) methodology, the carbon emissions of coal mining enterprises can be categorized into phases including coal extraction, coal beneficiation, transportation and storage, utilization and consumption, as well as other associated processes. Within this model, sources of carbon emissions have been systematically summarized. Direct carbon emissions encompass CO2 emissions from fuel combustion and methane (CH4) fugitive emissions. Indirect carbon emissions, on the other hand, include those associated with the net purchase of electricity and water consumption. The results of the accounting process indicate that the annual carbon emission of open-pit coal mine is 1538178.60 tCO2e, and the carbon dioxide equivalent emission per 1 t of raw coal produced is 0.05 tCO2e, which mainly comes from methane fugitive emissions caused by coal mining and post-mine activities (accounting for 79.92%). In addition, carbon emissions from fossil fuel combustion account for 13.71% of the total carbon emissions; whereas emissions associated with electricity and water consumption represent the smallest proportion, at 6.37%. The average annual greenhouse gas emissions of open-pit coal mines in China in the past ten years are 3.24 (±0.77) ×107 tCO2e, which is equivalent to the annual carbon sequestration of 5.23 (±1.24) ×108 trees, which is converted into the annual carbon sequestration of 113.83 (±27.00) hectares of poplar forests. At the same time, according to the current mining methods and processes, the country will generate more than 2.3 billion yuan of additional economic expenditure every year, and with the increase in open-pit coal mining, it will increase year by year. Therefore, reducing carbon emissions during the open-pit coal mining process is of significant importance, with particular emphasis needed on mitigating fugitive emissions. The research findings have significant implications for the development of a standardized carbon emissions accounting system in the coal industry and for assessing its regional environmental impact.

     

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