风电场生命周期CO2排放核算与不确定性分析

提出了风力发电技术生命周期能耗和CO2排放核算的详细方法.应用上海某风电场数据进行核算,结果认为,风机生产阶段能耗和CO2排放占风电场生命周期能耗和CO2排放的比例均为最大,分别为68.23%和67.18%.不确定性分析认为,在所有强度参数中,钢生产综合能耗最为灵敏.风电场能耗强度和CO2强度分别为3.24gce/(kW?h)和9.47g/(kW?h),明显低于300MW火力发电机组的相同指标,分别为330gce/(kW?h)和915g/(kW?h). 20a服役期的50MW风电场满期后,同比300MW火电机组少排放CO2约234万t.     

基于LCA的钢铁联合企业CO_2排放影响因素分析

钢铁企业是CO2排放大户,减少吨钢CO2排放是钢铁企业节约能源、保护环境、走可持续发展道路的必然要求.本研究旨在对钢铁企业产品生命周期清单研究的基础上,识别钢铁企业CO2排放的主要影响因素,提出针对性的减排建议.以某钢铁联合企业的产品生命周期清单模型为平台,同时利用TornadoChart工具,计算得到对企业CO2排放影响较大的因素,然后提出了相应的减排措施.结果表明,转炉流程对于钢铁企业的影响要大于电炉流程;对该企业CO2排放有重大影响和相关影响的因素有:高炉煤气(BFG)的CO2排放系数、连铸坯的钢水单耗、热轧的板坯单耗、转炉的铁水比.减少钢铁联合企业CO2排放的有效措施是采取捕集BFG中的CO2、降低转炉的铁水比、加强副产煤气的回收以及优化企业的产品生产结构.     

上海市终端能源消费的CO2排放影响因素定量分析

以对数平均指数法(LMDI)方法为基础,探讨了包括生活能耗在内的上海市终端能源消费CO2排放影响因素的分解方法,定量研究了能源强度下降、能源结构优化、产业结构调整、经济发展规模和人口数量等影响因素对CO2排放变化量的贡献率.研究表明,上海市2005~2009年CO2排放增长了2949万t,如果不采取任何减缓措施,经济增长和人口数量增加将导致CO2排放增长量相当于现在的2.5倍.能源强度下降、能源结构优化和产业结构调整起到了减缓CO2排放增长的作用,对减缓CO2排放增长的贡献率分别为-98%、-50%和-22%.与2000~2005年对比分析发现,工业部门能源强度下降和能源结构优化的减缓作用都有所下降,而产业结构调整开始发挥减排的作用,但贡献率还很低.生活能耗的CO2排放影响因素中,相较于人口数量增长,人均生活能耗上升是导致CO2排放增加的主要因素,且贡献率逐渐增大.     

中国铝生命周期能耗与碳排放的情景分析及减排对策

铝工业是高能耗高排放工业,探索铝工业的节能减排路径有助于我国实现《巴黎协定》中的温室气体减排承诺.采用物质流分析和生命周期评价方法,基于存量水平、技术水平和能源结构设置了15种情景,研究了我国铝工业1990～2100年的能耗和碳排放量,探索不同路径下的节能减排潜力.我国铝在用存量将在2040～2050年达到峰值(4.6...     

中国流通业CO2排放的因素分解和脱钩分析

参照IPCC清单中的方法估算了2000~2012年中国流通业CO2排放量;运用LMDI方法分解分析了研究期间流通业CO2排放变化的影响因素;并基于DPSIR框架构建流通业脱钩努力指数模型测度了流通业CO2排放脱钩效应.结果表明:2000~2012年间,流通业CO2排放量增长明显,期间累计排放总量为692482.37万t;产业规模效应是CO2排放增量的主要因素,能源强度效应是CO2排放减量的主要因素,分别引起CO2排放量增加了67435.72万t和减少了12358.67万t,能源结构和排放因子效应对CO2排放影响有限,分别引起CO2排放量增加了519.89万t和减少了2590.94万t;流通业CO2排放脱钩状态呈“弱脱钩—未脱钩—弱脱钩—未脱钩”的变化特征,脱钩努力指数值呈“ ”型变化趋势;目前能源强度是决定流通业CO2排放脱钩状态的关键因素,但随着能源强度的下降幅度越来越小,未来更需要通过调整能源结构和降低排放因子来实现流通业CO2排放脱钩.     

天津市生活垃圾处理碳排放时间变化特征及影响因素

控制生活垃圾处理产生的温室气体已成为碳减排的重点方向之一。参考《省级温室气体清单编制指南（试行）》推荐方法核算了天津市2009—2018年生活垃圾处理碳排放量,分析碳排放时间变化特征,并采用改进Kaya恒等式和LMDI加和分解法的碳排放影响因素分解恒等式,分析天津市生活垃圾处理碳排放的影响因素。结果表明：2009—2018年天津市生活垃圾处理碳排放量呈现先降后增的趋势,碳排放量主要来自填埋处理;影响碳排放的因素中,经济产出效应（ΔY）对生活垃圾处理碳排放的驱动作用最大,碳排放强度效应（ΔCF）次之,生活垃圾排放强度效应（ΔWI）和生活垃圾处理结构强度（ΔWS）对碳排放具有负向作用。控制生活垃圾产生量、增加垃圾焚烧处理占比以及提高填埋场甲烷回收率是未来主要的减排方向。

     

缸内直喷汽油车颗粒物排放特征及影响因素

随着经济的发展,机动车排放已成为大气颗粒物的重要来源,能够影响人类健康和气候变化.本研究通过整车转鼓实验对国V缸内直喷（GDI）汽油车的颗粒物排放水平及化学组成进行了研究,并探究了汽油车颗粒物排放的影响因素.研究结果表明,我国GDI汽油车的PM、OC、EC排放因子分别为（43.4±16.2）、（11.0±3.5）及（20.5±8.1）mg·kg^-1,其中EC的排放显著高于同类研究.为探索导致颗粒物排放区别的影响因素,本研究探讨了燃油类型、启动方式和循环设定对汽油车颗粒物排放的影响.结果表明,燃油类型（添加体积分数10%的乙醇与纯汽油）对颗粒物排放影响不大.冷启动会排放更多的颗粒物.同时,循环方式也会影响颗粒物排放,中国工况循环（CLTC）会排放比全球测试循环（WLTC）更多的颗粒物,这可能与我国更多的缓加速情况相关.     

A life cycle comparison of greenhouse emissions for power generation from coal mining and underground coal gasification

Underground coal gasification (UCG) is an advancing technology that is receiving considerable global attention as an economic and environmentally friendly alternative for exploitation of coal deposits. UCG has the potential to decrease greenhouse gas emissions (GHG) during the development and utilization of coal resources. In this paper, the life cycle of UCG from in situ coal gasification to utilization for electricity generation is analyzed and compared with coal extraction through conventional coal mining and utilization in power plants. Four life cycle assessment models have been developed and analyzed to compare (greenhouse gas) GHG emissions of coal mining, coal gasification and power generation through conventional pulverized coal fired power plants (PCC), supercritical coal fired (SCPC) power plants, integrated gasification combined cycle plants for coal (Coal-IGCC), and combined cycle gas turbine plants for UCG (UCG-CCGT). The analysis shows that UCG is comparable to these latest technologies and in fact, the GHG emissions from UCG are about 28 % less than the conventional PCC plant. When combined with the economic superiority, UCG has a clear advantage over competing technologies. The comparison also shows that there is considerable reduction in the GHG emissions with the development of technology and improvements in generation efficiencies.     

Avoiding CO2 capture effort and cost for negative CO2 emissions using industrial waste in chemical-looping combustion/gasification of biomass

Chemical-looping combustion (CLC) is a combustion process with inherent separation of carbon dioxide (CO₂), which is achieved by oxidizing the fuel with a solid oxygen carrier rather than with air. As fuel and combustion air are never mixed, no gas separation is necessary and, consequently, there is no direct cost or energy penalty for the separation of gases. The most common form of design of chemical-looping combustion systems uses circulating fluidized beds, which is an established and widely spread technology. Experiments were conducted in two different laboratory-scale CLC reactors with continuous fuel feeding and nominal fuel inputs of 300 W_th and 10 kW_th, respectively. As an oxygen carrier material, ground steel converter slag from the Linz–Donawitz process was used. This material is the second largest flow in an integrated steel mill and it is available in huge quantities, for which there is currently limited demand. Steel converter slag consists mainly of oxides of calcium (Ca), magnesium (Mg), iron (Fe), silicon (Si), and manganese (Mn). In the 300 W unit, chemical-looping combustion experiments were conducted with model fuels syngas (50 vol% hydrogen (H₂) in carbon monoxide (CO)) and methane (CH₄) at varied reactor temperature, fuel input, and oxygen-carrier circulation. Further, the ability of the oxygen-carrier material to release oxygen to the gas phase was investigated. In the 10 kW unit, the fuels used for combustion tests were steam-exploded pellets and wood char. The purpose of these experiments was to study more realistic biomass fuels and to assess the lifetime of the slag when employed as oxygen carrier. In addition, chemical-looping gasification was investigated in the 10 kW unit using both steam-exploded pellets and regular wood pellets as fuels. In the 300 W unit, up to 99.9% of syngas conversion was achieved at 280 kg/MW_th and 900 °C, while the highest conversion achieved with methane was 60% at 280 kg/MW_th and 950 °C. The material’s ability to release oxygen to the gas phase, i.e., CLOU property, was developed during the initial hours with fuel operation and the activated material released 1–2 vol% of O₂ into a flow of argon between 850 and 950 °C. The material’s initial low density decreased somewhat during CLC operation. In the 10 kW, CO₂ yields of 75–82% were achieved with all three fuels tested in CLC conditions, while carbon leakage was very low in most cases, i.e., below 1%. With wood char as fuel, at a fuel input of 1.8 kW_th, a CO₂ yield of 92% could be achieved. The carbon fraction of C₂-species was usually below 2.5% and no C₃-species were detected. During chemical-looping gasification investigation a raw gas was produced that contained mostly H₂. The oxygen carrier lifetime was estimated to be about 110–170 h. However, due to its high availability and potentially low cost, this type of slag could be suitable for large-scale operation. The study also includes a discussion on the potential advantages of this technology over other technologies available for Bio-Energy Carbon Capture and Storage, BECCS. Furthermore, the paper calls for the use of adequate policy instruments to foster the development of this kind of technologies, with great potential for cost reduction but presently without commercial application because of lack of incentives.

     

中国省域农业源非CO2温室气体排放的影响因素分析与峰值预测

运用IPCC清单方法核算了中国各省(直辖市、自治区)农业源非二氧化碳(非CO₂)温室气体(GHG)的排放,基于Tapio弹性脱钩理论和情景预测法、STIRPAT模型和向量自回归模型(VAR)预测了其达峰时间和规模,并结合对数平均迪氏指数(LMDI)模型、STIRPAT模型和固定效应模型识别了中国农业非CO₂ GHG排放的影响因素.结果表明,高情景和中情景下中国农业非CO₂ GHG排放量整体呈上升趋势,到2050年仍未达峰;2018—2050年低情景下GHG排放量整体呈下降趋势,其中,低情景下已于2018年达峰,峰值为0.73×10⁹ t (以CO₂-eq计,下同);北京市、上海市、江苏省、浙江省、福建省、广东省、海南省、重庆市、四川省和青海省农业生产与其农业非CO₂ GHG排放呈强脱钩状态,其余21个省(直辖市、自治区)呈弱脱钩状态;除天津市和黑龙江省以外的29个省(直辖市、自治区),经济和人口为农业非CO₂ GHG排放的促进因素,效率和结构为其抑制因素.     

2020年中国发电行业碳减排目标规划相符性分析

基于发电行业节能减排技术的现有应用规划,预测3种不同的GDP增长情景,即减速发展,基准情景和高速发展情景下,若能实现我国现有关于发电行业节能减排技术的规划目标,2020年发电行业的CO2排放量将达到35.32,39.15,43.20亿t.同时基于中国2020年碳强度减排承诺,计算得国家2020年CO2排放目标在不同发展情景下将达到97.30~127.96亿t不等.结合上述结果讨论,发电行业规划目标相符要求2020年的CO2排放比例为33.27%~36.82%.结果表明,若能实现我国现有关于发电行业节能减排技术的规划目标,则对应于不同的GDP增长速度,发电行业总碳排放量能够完成国家承诺碳强度减排的分解目标.     

生活垃圾填埋场CH4及N2O释放规律及影响因素研究

对生活垃圾填埋场5个操作平台开展了为期1年的CH_4和N_2O释放通量监测,分析了填埋场CH_4和N_2O释放通量变化规律,并对CH_4和N_2O释放通量与CO2释放通量之间相关关系及其影响因素进行了探讨.结果表明,生活垃圾填埋场是CH_4和N_2O释放的源,CH_4释放通量范围为(9.16±7.46)~(21287.03±128.70)mg·m-2·h-1CH_4-C;N_2O释放通量范围为(31.74±16.00)~(17089.31±7599.24)μg·m~(-2)·h~(-1)N_2O-N;整个填埋场5个平台中CH_4和N_2O年释放总量分别约为86.17 Gg·a-1、0.81 Gg%a-1CO2当量,填埋场温室气体的减排主要是控制CH_4释放.生活垃圾填埋场是高度异质性体系,不同平台释放通量变化规律并不统一,N_2O与含水率呈显著负相关(p0.05),两种气体释放通量与土壤温度均呈显著正相关关系(p0.01),而与其他因素无明显相关关系.     

Turnover of dissolved organic carbon fuels nocturnal CO2 emissions from a headwater catchment reservoir, Southeastern China: Effects of ecosystem metabolism on source partitioning of CO2 emissions

Dam reservoirs in headwater catchments, as critical zones for their proximity to terrestrial sources, play important roles in dissolved organic carbon (DOC) cycling. However, the effects of ecosystem metabolism (EM) on DOC cycling are not well known. Here, in-situ diurnal and monthly observations were conducted to measure EM (including gross primary production (GPP), ecosystem respiration (ER) and heterotrophic respiration (HR)), DOC turnover and CO₂ emissions in a headwater catchment reservoir in Southeastern China in 2020. Our study showed the nocturnal CO₂ emission rate was about twice as high as in daytime, and was strongly driven by EM. The values for DOC turnover velocity ranged from 0.10 to 1.59 m/day, and the average DOC turnover rate was 0.13 day⁻¹, with the average removal efficiency of 12%. The contribution of respired DOC to daily CO₂ emissions ranged from 17% to 61%. The accumulated efficiencies were estimated to be 13% for the selected 15 reservoirs throughout the Changjiang River network, corresponding to about 0.34 Tg C/year of the respired DOC. The modified CO₂ flux was 0.75 Tg C/year, and respired DOC accounted for about 45% of total emitted CO₂ from the 15 larger reservoirs. Our research emphasizes the necessity of incorporating the effects of EM into studies of reservoir DOC removal and CO₂ emissions.     

太湖主要环湖河道沉积物反硝化潜力及其控制因子

河流反硝化作用是水体氮素去除的重要途径,对流域氮负荷削减具有重要意义.为探究河网区河道的反硝化脱氮能力及其主要控制因子,本研究调查了太湖14条主要环湖河道的水质和沉积物特征,通过泥浆培养实验,利用氮氩比的方法和膜接口质谱仪分析技术,测定了 14条环湖河道的沉积物反硝化潜力.结果表明,太湖环湖河道的反硝化潜力为-9.93...     

Simulation based life cycle assessment of airborne emissions of biomass-based ethanol products from different feedstock planting areas in China

Oil shortage and environmental deterioration urge people to pay more and more attention to Biomass-based Fuel Ethanol (BFE), because it is renewable and apparently environmentally friendly. This paper aims to assess and compare the air emissions of three BEF products from different feedstock planting areas in China. For the purpose of a “cradle to grave” study of biomass-based ethanol fuel as a substitute transportation fuel, the authors chose “vehicle fueled by biomass-based E10 (a blend of 10% ethanol and 90% gasoline, v/v)” as the subject. Then, life cycle emission models of Wheat-based E10 from central China, Corn-based E10 from northeast China, and Cassava-based E10 from southwest China were set up based on surveys; life cycle emission functions of CO₂, CO, N₂O, NO_x, SO₂, CH₄, VOC, and PM₁₀ were constructed and value of each emission category was calculated based on Monte Carlo simulation of the life cycle emission models. The calculation results showed that compared with gasoline-fueled vehicles, biomass-based E10-fueled vehicles release less CO₂ and VOC in their lifecycles, but wheat-based E10-fueled and cassava-based E10-fueled ones have more emissions of CO, CH₄, N₂O, NO_x, SO₂, PM₁₀ and corn-based E10-fueled ones have more emissions of CH₄, N₂O, NO_x, SO₂, PM₁₀. Suggestions on reducing the emissions have been proposed for future actions.     

基于10辆轻型汽油车的实际行驶与台架工况排放特征及影响因素研究

利用便携式排放测试系统(Portable emission measurement system,PEMS)分析了10辆轻型汽油车分别在实验室台架和实际行驶排放(Real driving emission,RDE)工况下典型空气污染物的排放特征和影响因素.测试结果表明,轻型汽油车在冷启动和热启动阶段产生的一氧化碳(CO)、碳氢化合物(HC)、氮氧化物(NO_x)分别是热运行1阶段和热运行2阶段的28.0、32.9、28.4倍和4.0、11.2、5.4倍,表明车辆启动对机动车排放贡献显著.台架工况排放因子受车辆启动排放影响较大,在台架实验去除启动排放影响的情况下,台架CO₂、CO、HC和NOx排放因子将分别减小2.3%±1.3%、44.2%±30.6%、47.5%±29.6%和44.9%±30.8%.在相同速度下,RDE工况下的CO₂排放因子相比不考虑启动排放的台架工况排放因子要高出31.7%±5.0%.单车瞬态排放数据分析结果表明,RDE测试相比于台架工况测试覆盖了更多的机动车行驶工况特征,可以更准确地量化车辆在实际道路行...     

闽江河口表层水体氧化亚氮释放时空变化特征及其影响因素

以闽江口水体为研究对象,研究了闽江河口上段(城市河口段)、河口中段和河口下段(口外海滨段)不同季节水体N₂O的溶存浓度、水-气界面通量及其环境影响因子.结果表明,闽江口水体N₂O溶存浓度为0.99～55.92 nmol·L^-1,N₂O饱和度为8.0%～396%,水-气界面N₂O释放通量为-5.21～7.91μg·m^-2·h^-1.从季节差异看,7月(夏季)、9月(秋季)和12月(冬季)水体中N₂O过饱和,表现为N₂O的排放“源”;4月(春季)水体中N₂O不饱和,表现为N₂O“汇”.水-气界面N₂O释放通量呈夏、秋和冬季高,春季低的季节变化规律.在空间变化上,水-气界面N₂O释放通量从河口上段到下段降低,与氮含量变化趋势一致.N₂O间接性释放因子为0.004%～0.128%,低于IPCC...     

中国水泥碳排放测算的影响因素分析与不确定度计算

作为水泥生产大国和CO_2排放大户,中国水泥行业的CO_2排放在国际上受到越来越广泛的重视,然而不同的研究结果之间存在不同程度的差异.为了定量研究中国水泥碳排放测算的影响因素,对碳排放因子的测算、运营边界的界定及水泥熟料或水泥成品的产量这3个影响因素做了详细分析,并对碳排放因子的不确定度做了定量计算.结果发现,影响中国水泥碳排放测算的最主要因素是碳排放因子,而该因素又与生产工艺、燃料和熟料水泥比等密切相关.本研究结果比IPCC、EDGAR、CDIAC和WBCSD/CSI等研究结果均低,并且差异逐年显著,以水泥碳排放来自碳酸盐分解的部分为例,2000年相差约65 Mt,而2012年差值接近450 Mt.计算表明,中国水泥碳排放不确定度为12%~22%.因此,水泥碳排放测算的影响因素较多,在计算中国水泥碳排放量时不可照搬国外研究的参数.     

三江平原泥炭沼泽湿地N2O排放通量及影响因子

运用静态暗箱-气相色谱法观测了三江平原毛苔草泥炭沼泽湿地植物生长季N2O排放通量,并分析了其关键影响因子.结果表明:生长季N2O排放通量季节变化动态明显,最大值出现在7月上旬;平均排放通量为76.77μg/(m2·h),高于潜育沼泽湿地[20~60μg/(m2·h), 2002~2005].N2O排放通量与土壤温度存在极显著指数关系(P<0.01),且随土壤深度(土壤10cm以下)的增加相关关系逐渐减弱;与水位呈极显著负相关关系(P<0.01);另外,植被是影响N2O排放的主要生物因子,有植被参与的N2O排放是无植被的1.7倍.总之,水位和土壤温度是控制泥炭沼泽N2O排放呈明显季节变化的主要因素,而土壤水文物理特性的差异是引起泥炭沼泽N2O排放高于潜育沼泽的主要原因.经初步估算,三江平原泥炭沼泽每年植物生长季N2O排放总量约为72.9Mg,表明泥炭沼泽湿地在生长季是重要的N2O潜在排放源.     

Atmospheric impacts of the life cycle emissions of fuel ethanol in Brazil: based on chemical exergy

An assessment is made of the atmospheric emissions from the life cycle of fuel ethanol coupled with the cogeneration of electricity from sugarcane in Brazil. The total exergy loss from the most quantitative relevant atmospheric emission substances produced by the life cycle of fuel ethanol is 3.26E+05 kJ/t of C₂H₅OH. Compared with the chemical exergy of 1 t of ethanol (calculated as 34.56E+06 kJ), the exergy loss from the life cycle's atmospheric emission represents 1.11% of the product's exergy. The activity that most contributes to atmospheric emission chemical exergy losses is the harvesting of sugarcane through the methane emitted in burning. Suggestions for improved environmental quality and greater efficiency of the life cycle of fuel ethanol with cogenerated energy are: harvesting the sugarcane without burning, renewable fuels should be used in tractors, trucks and buses instead of fossil fuel and the transportation of products and input should be logistically optimized.