适用于生物质直接耦合煤发电过程的温室气体核算方法优化

Optimization of greenhouse gas accounting methods applicable to biomass direct-coupled coal power generation processes

生物质与煤直接耦合燃烧发电作为降低火电行业碳排放的关键技术选择得到广泛关注,在双碳目标的推动下,准确量化生物质掺烧电力生产过程温室气体排放能有效提升发电行业碳排放数据的准确性与一致性,确保国内碳排放交易市场向更公平稳定的方向发展。介绍了国内外生物质耦合煤发电机组碳核算方法,提出生物质直接耦合发电机组温室气体核算边界、计算方法和核算参数的选取原则。结果表明:与现行核算法相比,基于生物质直接耦合煤发电的温室气体核算方法在核算边界、核算范围和计算方法上均有一定差异。对于核算边界,有必要新增燃料燃烧过程N_(2)O排放、新增设备资源带来的间接碳排放;针对常见生物质是否可视为零碳燃料进行评估,发现在各省份生物质的最佳经济运输半径内秸秆、城市垃圾、林类剩余物等常见生物质均达到温室气体减排要求,且合理运输范围(48 km)内均可视为零排放;在计算方法上,燃料消耗量建议根据碳排放量分层级选取测定方法,小比例掺烧时碳氧化率可直接选取缺省值99%,并且建议核算脱硫环节带来的碳排放,对循环流化床燃烧温度在1123 K以下的工况需要进行N_(2)O核算。

Direct coupled combustion of biomass and coal for power generation has gained widespread attention as a key technology option for reducing carbon emissions in the coal power sector.Driven by Carbon Peaking and Carbon Neutrality Goals,the accurate quantification of greenhouse gas(GHG)emissions from biomass-coupled power production processes can effectively improve the accuracy and consistency of carbon emission data in the power generation industry and ensure the development of the domestic carbon trading market in a more fair and stable direction.Carbon accounting methods for biomass-coupled coal generating units at home and abroad were first introduced.Then the biomass direct-coupled generating unit greenhouse gas accounting boundary,calculation method and the selection principle of accounting parameters were proposed with reference to the experience of European and American countries.The results show that,compared with the current accounting method,the GHG accounting method based on biomass directly coupled with coal power generation has some differences in the accounting boundary,accounting scope and calculation method.For the accounting boundary,it is necessary to add N_(2)O emissions from the fuel combustion process and indirect carbon emissions from new equipment resources.The common biomass fuels were evaluated to see if zero emissions could be considered,and common biomasses was found,such as straw,municipal solid waste,and forest residues,met the GHG emission reduction requirements within the optimal economic transportation radius of the biomass in each province,and zero emissions within the reasonable transportation range(48 km)could be considered.In the calculation method,fuel consumption was recommended to select the measurement method according to the carbon emission stratification,the carbon oxidation rate could be directly selected as the default value of 99%in the case of small-ratio blending,carbon emission brought by the desulfurization link calculation is recommended,and the N_(2)O accounting was needed for the circulating fluidized bed combustion temperature under the working condition of 1123 K.