低碳沼气工程建设的生态经济效益核算研究——以广西恭城瑶族自治县为例

在全球气候变暖和快速城市化的背景下,农村地区是能源集约消耗的薄弱区域,其经济、社会、生态的可持续发展一直受到制约。沼气工程作为一种清洁用能方式,在优化用能结构、减少环境污染、节约自然资源、增加农民收入和促进农村经济转型等方面具有较大优势。本文选择广西恭城瑶族自治县这一沼气工程建设全国示范县为案例,针对户用8m3沼气池,对施工建设、运营维护和消费利用全生命周期过程中的碳足迹、减排效益、经济收益和生态价值方面进行核算和评价。结果表明在沼气池的建设与正常使用年限内,该县农户通过替代燃煤、柴薪和秸秆等共可减排CO2约1.24×106t。从户用沼气池建设及生产过程的投入产出价值的来看,仅通过节约炊事燃料和沼液沼渣的回收利用就能为每户节约19 877元,为全县带来1.26亿余元的总收益。因此,沼气工程在该地区的建设普及是发展农村低碳经济、走富农之路的有效措施,可为广大西部地区新农村建设提供借鉴。     

Comprehensive Appraisal of Provincial Low Carbon Development： A Case Study of China

In this research,the Factor Analysis model of measuring provincial low carbon development in China has been constructed.Based on data from 30 provinces,an empirical study was developed to measure comprehensive low carbon development using the Factor Analysis model(Principal Components method and Normalized Varimax Rotation).The results reveal that the provincial marks of low carbon development are generally low and only nine provinces have high marks(more than 0.80).The results also show significant regional disparity.The provincial marks of the eastern region are higher than both the middle and western provinces of mainland China.All of the provinces with high marks(more than 0.90) are located in the eastern region,and those with the lowest marks(0.60) are located in the middle region.Furthermore,regional disparity in low carbon development follows the same pattern as economic development in China.Finally,some suggestions for decision-makers are presented.     

含外来电的崇明县能源碳排放核算研究

能源消耗是中国最主要的碳排放源,而地方政府是碳管理的基层行政单元,因此,有效控制区域的能源碳排放是碳减排工作的重中之重。区域消耗的能源中,外来电是缓解当地用电压力的重要措施,但一般外来电引起的碳排放易被忽视。将外来电导致的碳排放纳入区域能源碳排放核算体系内,利用部门分析和范围分析法建立了包含外来电分析的能源碳排放核算系统,以上海市崇明县为例进行了应用。研究表明：（1）2000～2009年崇明的能源碳排放增长较快,由181万t增至477万t（CO2当量）;(2）碳排放总量的8212%来自3个部门：工业、建筑业和生活部门;(3）2009年,购买电力导致的间接碳排放达2316%,体现了实施碳管理时考虑外来电力的必要性     

湖南省碳源与碳汇变化的时序分析

在全球气候变暖的背景下,减少温室气体排放、发展低碳经济成为各地区在发展中的普遍共识。以湖南省为研究区域,以1995~2008年为研究时序,从能源消费、主要工业产品生产工艺过程、土地利用变化与牲畜管理、固体废弃物处理与废水处理和排放4个方面综合分析了碳源与碳汇的变化情况。研究表明:1995~2008年,湖南省温室气体排放总量约在220亿t（2000年）至399亿t（2008年）CO2当量之间,14 a间增长了6118%,年均增长374%;碳汇总量约在1754亿t（1995年）至2537亿t（2007年）CO2当量之间,14 a间增长了3607%,年均增长约240%;能源消费与农业部门是湖南省温室气体的主要来源,林地是湖南省碳汇的主要来源;综合碳源与碳汇变化的均衡结果,1995~2008年湖南省呈碳汇盈余状态,净碳汇在2001~2007年持续增加,14 a间增长了31.94%,年均增长2.15%     

CFRP加固高强混凝土梁锚固方式试验研究

高强混凝土梁受拉底面粘贴补强纤维布后,延性降低显著。为提高补强梁的综合性能,利用四点弯曲梁静载试验,在补强加固梁梁端及跨中实施不同的锚固方式,对比不同锚固组合下加固梁的强度和延性。研究表明:端部U锚能改善加固梁破坏模式,提高加固梁的延性和强度及补强纤维布的利用率。端部U锚联合跨中全包锚固能进一步提高加固梁的延性,显著提高补强纤维布的利用率,且能平衡变形性和承载力在安全储备中的比重;在补强纤维布断裂后,能有效限制补强纤维布的剥离和滑移,继续发挥补强作用,使加固梁延性和强度得以恢复;能对包裹区混凝土产生约束作用,提高混凝土的延性。因此端部U锚联合跨中全包锚固是合理且有充分安全储备的锚固方式。     

Role of black carbon in the distribution of polychlorinated dibenzo-p-dioxins/dibenzofurans in aged field-contaminated soils

Floodplain soils containing elevated levels of polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs) were collected from several locations along the Tittabawassee River (Michigan, USA). The PCDD/F profiles of these soils exhibited distinct congener patterns consistent with byproducts from either chloralkali manufacturing or chlorophenols productions. Black carbon (BC) particles were isolated for the first time from floodplain soil impacted by PCDD/Fs. Petrographic analysis showed that BC particles, including coal, oxidized coal, metallurgical coke, depositional carbon, coal tar/pitch, cenosphere, and charcoal, comprised approximately 30% by volume of the organic fraction with size range of 250 μm-2000 μm from a typical floodplain soil. The BC particles with anthropogenic origin such as pitch and coke associated with the chloralkali production process served as both the source and subsequent transporter for the highly hydrophobic PCDD/Fs. These anthropogenic BC particles were enriched with high levels of PCDFs, containing approximately 1000-fold the concentration found in the bulk soil. The strong association of PCDD/Fs with anthropogenic BC directly impacts the physicochemical and biological availability thus the risk associated with these hydrophobic organochlorines in soils and sediments.     

Development of a combined isotopic and mass-balance approach to determine dissolved organic carbon sources in eutrophic reservoirs

A combined mass-balance and stable isotope approach was set up to identify and quantify dissolved organic carbon (DOC) sources in a DOC-rich (9 mg L⁻¹) eutrophic reservoir located in Western France and used for drinking water supply (so-called Rophemel reservoir). The mass-balance approach consisted in measuring the flux of allochthonous DOC on a daily basis, and in comparing it with the effective (measured) DOC concentration of the reservoir. The isotopic approach consisted, for its part, in measuring the carbon isotope ratios (δ¹³C values) of both allochthonous and autochthonous DOC sources, and comparing these values with the δ¹³C values of the reservoir DOC. Results from both approaches were consistent pointing out for a DOC of 100% allochthonous origin. In particular, the δ¹³C values of the DOC recovered in the reservoir (−28.5 ± 0.2‰; n = 22) during the algal bloom season (May-September) showed no trace of an autochthonous contribution (δ¹³C in algae = −30.1 ± 0.3‰; n = 2) being indistinguishable from the δ¹³C values of allochthonous DOC from inflowing rivers (−28.6 ± 0.1‰; n = 8). These results demonstrate that eutrophication is not responsible for the high DOC concentrations observed in the Rophemel reservoir and that limiting eutrophication of this reservoir will not reduce the potential formation of disinfection by-products during water treatment. The methodology developed in this study based on a complementary isotopic and mass-balance approach provides a powerful tool, suitable to identify and quantify DOC sources in eutrophic, DOC-contaminated reservoirs.     

Adsorptive removal of an acid dye by lignocellulosic waste biomass activated carbon: equilibrium and kinetic studies

Chemically prepared activated carbon material derived from palm flower was used as adsorbent for removal of Amido Black dye in aqueous solution. Batch adsorption studies were performed for the removal of Amido Black 10B (AB10B), a di-azo acid dye from aqueous solutions by varying the parameters like initial solution pH, adsorbent dosage, initial dye concentration and temperature with three different particle sizes such as 100 μm, 600 μm and 1000 μm. The zero point charge was pH 2.5 and the maximum adsorption occurred at the pH 2.3. Experimental data were analyzed by model equations such as Langmuir, Freundlich and Temkin isotherms and it was found that the Freundlich isotherm model best fitted the adsorption data and the Freundlich constants varied from (K_F) 1.214, 1.077 and 0.884 for the three mesh sizes. Thermodynamic parameters such as ΔG, ΔH and ΔS were also calculated for the adsorption processes and found that the adsorption process is feasible and it was the endothermic reaction. Adsorption kinetics was determined using pseudo first-order, pseudo second-order rate equations and also Elovich model and intraparticle diffusion models. The results clearly showed that the adsorption of AB10B onto lignocellulosic waste biomass from palm flower (LCBPF) followed pseudo second-order model, and the pseudo second-order rate constants varied from 0.059 to 0.006 (g mg⁻¹ min) by varying initial adsorbate concentration from 25 mg L⁻¹ to 100 mg L⁻¹. Analysis of the adsorption data confirmed that the adsorption process not only followed intraparticle diffusion but also by the film diffusion mechanism.     

论碳关税的福利效应

哥本哈根会议上碳关税引发热议,成为发达国家和发展中国家讨论的焦点.本文从碳关税的内涵出发,梳理了有关碳关税问题的已有研究,通过建立一个简单的局部均衡模型,对征收碳关税情况下进口国、出口国的福利以及全球福利变化进行了分析,研究得出:进口国征收碳关税能提高本国福利水平,减低出口国的福利水平,但福利变化程度取决于进口国国内碳税、出口国是否征税国内碳税、进出口国国内碳密集度水平等情况.进一步.由于温室气体排放是全球公共品,用全球福利最大化代替进口国福利最大的约束条件,探讨了最优碳关税的确定方法,认为最优碳关税取决于需求函数和供给函数的值,由出口国国内碳税与外部性的差异与进口国国内碳税与外部性差异的比值来决定.温室气体减排是国际贸易面临的新问题,碳关税仅仅拉开了以气候变化之名进行国际贸易保护的序幕,如何有效地将国际气候变化规则纳入国际贸易利益的维护中是我们未来面临的重要课题.     

北京现代都市低碳农业的前景与策略

现代都市发展低碳农业是降低温室气体排放,实现国家宏观战略目标的重要组成部分.本文对低碳农业的定义、特征进行了初步阐述,认为低碳农业是通过技术改进和制度创新建立起来的一种低投、高产、低(负)碳、生态的现代农业,具有系统开放性、技术集成性、生命周期性、过程安全性四个特征.利用碳汇/源平衡方法分析北京农业现状,结果表明:目前北京农业领域的碳源与汇分别为10-20 TgCO2eq·a-1和10.23-14.16 TgCO2eq·a-1,碳源基本稳定,碳汇还有较大的发展潜力.根据北京市生态特点和未来农业的定位,发展低碳农业,在技术层面上,可以加强与种植相关的土壤碳汇建设,与养殖相关的减排和其他减排技术;在制度层面上,建立农业布局调整机制,大力发展清洁生产机制、生态补偿机制、农业准入机制和综合调节机制.预测北京低碳农业的前景,初步估算未来北京农业的碳汇潜力可以达到20-30 TgCO2eq·a-1,直接的碳源可以减少到4-5 TgCO2eq·a-1.通过发展低碳农业,不仅可以抵消农业碳源,还能抵消6%-10%总温室气体,真正起到净碳汇功能.