西藏东南部森林可燃物特点及气候变化对森林火灾的影响

根据西藏林芝地区的DEM数据和植被分布数据分析了该地区可燃物的水平分布和垂直分布规律,并根据火发生纪录分别计算了火发生周期和发生概率,根据火灾高发期的降水和气温数据分析降水和气温的变化趋势,本地区易发生火灾的可燃物主要有高山松云南松林,草甸灌丛,云冷杉林等.该地区的火灾轮回期为17178 a,火发生概率为0.00006,远远低于东北林区,但由于该地区处于高海拔地区,生态系统脆弱,林木蓄积量大,积累能量高,潜在的火强度高.林芝地区夏季降水减少,火灾高发期(2～5月)降水有所增加,但增温明显,气温升高对高海拔地区的影响比低海拔地区更大,对于森林可燃物而言,气温增高使高海拔地区的森林火险增大,森林防火面临的形势更加严峻.     

Energy recovery from solid waste fuels using advanced gasification technology

Since the mid-1980s, TPS Termiska Processer AB has been working on the development of an atmospheric-pressure gasification process. A major aim at the start of this work was the generation of fuel gas from indigenous fuels to Sweden (i.e. biomass). As the economic climate changed and awareness of the damage to the environment caused by the use of fossil fuels in power generation equipment increased, the aim of the development work at TPS was changed to applying the process to heat and power generation from feedstocks such as biomass and solid wastes. Compared with modern waste incineration with heat recovery, the gasification process will permit an increase in electricity output of up to 50%. The gasification process being developed is based on an atmospheric-pressure circulating fluidised bed gasifier coupled to a tar-cracking vessel. The gas produced from this process is then cooled and cleaned in conventional equipment. The energy-rich gas produced is clean enough to be fired in a gas boiler (and, in the longer term, in an engine or gas turbine) without requiring extensive flue gas cleaning, as is normally required in conventional waste incineration plants. Producing clean fuel gas in this manner, which facilitates the use of efficient gas-fired boilers, means that overall plant electrical efficiencies of close to 30% can be achieved. TPS has performed a considerable amount of pilot plant testing on waste fuels in their gasification/gas cleaning pilot plant in Sweden. Two gasifiers of TPS design have been in operation in Grève-in-Chianti, Italy since 1992. This plant processes 200 tonnes of RDF (refuse-derived fuel) per day. It is planned that the complete TPS gasification process (including the complete fuel gas cleaning system) be demonstrated in several gas turbine-based biomass-fuelled power generating plants in different parts of the world. It is the aim of TPS to prove, at commercial scale, the technical feasibility and economic advantages of the gasification process when it is applied to solid waste fuels. This aim shall be achieved, in the short-term, by employing the cold clean product gas in a gas boiler and, in the longer-term, by firing the gas in engines and gas turbines. A study for a 90 MWth waste-fuelled co-generation plant in Sweden has shown that, already today, gasification of solid waste can compete economically with conventional incineration technologies.     

一株以喹啉为燃料的产电假单胞菌(Pseudomonas sp.)Q1的特性研究

微生物燃料电池(Microbial fuel cell,MFC)阳极微生物的种类和作用机制对MFC的产电性能有着重要影响.从稳定运行了210d,以200mg·mL-1喹啉为燃料的MFC阳极室分离得到一株革兰氏阴性菌,命名为Q1,其16S rRNA基因序列与Pseudomonas citronellolisDSM50332T的同源性为96.9%,属于假单胞菌属(Pseudomonassp.).循环伏安法及构建纯菌MFC方法的测定结果均表明Q1具电化学活性.菌株Q1能利用单一喹啉或喹啉和葡萄糖混合燃料产电.在本试验所用浓度范围内,增加葡萄糖浓度,菌株Q1对应的最高输出电压增加,增加喹啉浓度菌株Q1的产电性能则降低,研究表明,菌株Q1库仑量和库仑效率达到最高时(分别为18.65C和36.56%),存在一个最佳喹啉与葡萄糖浓度比1∶3.在MFC中喹啉的降解效果优于普通厌氧培养,葡萄糖对菌株Q1降解喹啉有促进作用,以喹啉和葡萄糖为混合燃料24h对喹啉的去除率达99.53%,优于以单一喹啉为燃料的情况.循环伏安法和不同更换基质方式试验表明,附着在电极上的菌株Q1对产电起主要作用,Q1的溶解态代谢产物对产电过程起电子介体的作用.     

可燃固废复合燃料的燃烧性能试验研究

焚烧法具有显著的减容、资源化和能量回收等优点,是生活垃圾处理的有效途径。原生垃圾成分复杂、含水率高、热值低,直接焚烧处理的热稳定性差。将生活垃圾、市政污泥及适量的辅料,采用正交表配料制备可燃固废复合燃料。通过燃烧热稳定性、热值试验的极差分析和方差分析检验燃料的燃烧性能,得出原料配比、园林残余及固硫剂对燃料燃烧特性有显著的影响;运用数量化理论分析,得到热稳定性、热值指标的预测方程,置信度>90%;最后采用综合评分法筛选出燃烧性能最优的燃料制备配方为:垃圾、市政污泥、煤粉以2:1:1比例混合,助燃剂MnO2添加量为0.19%,固硫剂CaO添加量为0.6%时,制备的燃料燃烧热值为18.702kJ/g,燃烧热稳定性(TS+6)达74.79%。     

Bioenergy recovery from landfill gas: A case study in China

Landfill gas (LFG) utilization which means a synergy between environmental protection and bioenergy recovery was investigated in this study. Pressure swing adsorption technology was used in LFG purification, and laboratory experiment, pilot-scale test, and on-site demonstration were carried out in Shenzhen, China. In the laboratory experiment, A-type carbon molecular sieve was selected as the adsorbent by comparison of several other adsorbents. The optimal adsorption pressure and adsorption time were 0.25 MPa and 2 min, respectively, under which the product generation rate was 4.5 m³/h and the methane concentration was above 90%. The process and optimization of the pilot-scale test were also reported in the paper. The product gas was of high quality compared with the National Standard of Compressed Natural Gas as Vehicle Fuel (GB18047-2000), when the air concentration in feed gas was under 10.96%. The demonstration project was composed of a collection system, production system, and utilization system. The drive performance, environmental protection performance, and economic feasibility of the product gas — as alternative fuel in passenger car, truck, and bulldozer—were tested, showing the feasibility technology for LFG utilization.     

产气肠杆菌燃料电池产电机制研究

基于铁还原菌的微生物燃料电池（MFCs）与基于产氢细菌的MFCs各有优劣,前者能量利用效率高,但底物利用范围有限;后者底物利用广泛,但其依靠悬浮细胞产电,电子回收率较低.本研究以1株具有铁还原活性的产氢菌Enterobacter aerogenes XM02为产电微生物,构建了3种不同阳极材料的空气阴极MFCs,通过输出电压和库仑效率的比较以及扫描电镜观察阳极形貌等方法对此菌的产电机制进行探讨.结果发现,采用比表面积大且具有氢催化活性的碳毡作为阳极材料时,可显著改善MFCs性能,库仑效率由载铂碳纸阳极MFC的1.68% 提高至42.49%,远高于已报道的其它产氢菌燃料电池.扫描电镜证实大量细菌细胞附着在阳极表面,形成阳极生物膜.采用非生长基质实验排除悬浮细胞的产电作用,证明附着在阳极的生物膜对产电起主导作用,认为生物膜原位产氢-氧化是此菌的主要产电机制.     

环境因素对接种Shewanella baltica的微生物燃料电池产电能力的影响

通过筛选获得1株Shewanella baltica,分别改变阳极基质种类、浓度、pH和温度,考察不同条件下接种该菌后MFC产电特性.乳酸钠作为基质时接种该菌的MFC产电功率密度最大,MFC产电功率密度和基质浓度满足Monod模型.阳极溶液pH和温度对接种该菌的MFC产电功率密度影响最大.阳极溶液pH为8时接种该菌的MFC产电功率密度最大可达1236mW/m2,最大功率密度上升主要是阳极内阻和阳极电势影响所致.接种该菌的MFC最大产电功率密度在50℃达到1197mW/m2,最大功率密度随温度变化的主要原因是温度对阳极内阻的影响,20～50℃时MFC电流密度与温度满足Arrhenius方程.     

短臂型空气阴极微生物燃料电池产电特性研究

用夹子将质子交换膜和载铂量为0.2 mg/cm2碳纸固定在阳极室的短臂端口构成短臂型空气阴极微生物燃料电池.利用污泥电池从厌氧消化污泥中富集产电菌于石墨棒表面,循环伏安法检测发现这些微生物具有电化学活性.将富集好的石墨棒作为阳极用于短臂型空气阴极微生物燃料电池,以醋酸钠为底物时该电池的最大功率密度为738 mW/m2,内阻为280Ω,开路电压为741 mV.连续向阳极室通氮气和去掉质子交换膜可分别将电池的最大功率密度提高到745 mW/m2和759 mW/m2,当两者同时作用时最大功率密度可达到922 mW/m2,而这3种条件下电池的内阻仍保持在280Ω左右.当底物浓度在12.62~100.96 mg/L、外电阻为510Ω时,电池的最大输出电压和底物浓度之间存在明显的线性关系(R2=0.99).当底物浓度高于100.96 mg/L时,电池的最大输出电压不再增大并保持在302 mV(外电阻为510Ω).然而,电池的库仑效率则随着底物浓度的提高而提高,从31.83%逐渐增大到45.03%.     

单室型微生物燃料电池处理黄姜废水的性能研究

以黄姜废水为底物,采用单室型微生物燃料电池,验证了MFC处理黄姜废水的可行性,研究了进水COD和SO42-浓度对产电性能的影响.控制电导率和COD等条件一致,黄姜废水最大功率密度为葡萄糖配水的80.3%.低COD浓度条件下MFC产电稳定,功率密度随COD浓度上升而提高,最高为322 mW/m2;当COD提高至2766 mg/L以上时,MFC稳定产电的时长缩短且更新基质后无法恢复最佳产电水平,表明过高的COD负荷会抑制产电微生物活性.COD最终去除率在68.2%~84.8%之间,且随着初始浓度的提高去除率有所下降.进水SO42-浓度的提高使MFC输出功率密度增大,但当SO42-浓度>7 716 mg/L(电导率>8.19 mS/cm)时,继续提高SO42-浓度无法使功率密度增大.与沉淀SO42-后的废水比较,含硫原水的最大功率密度平均下降14.5%,其库仑效率也随SO42-浓度提高明显下降,表明存在SO42-作为电子受体被还原,降低了MFC的效率.     

柴油品质对1台典型欧Ⅳ柴油机性能影响的研究

为提出与我国第4阶段排放法规相适应的车用柴油标准,作为北京市"汽车-油品"项目的研究内容之一,在1台满足欧Ⅳ排放法规的柴油机上对不同品质参数的8种柴油进行对比试验.结果表明,柴油品质参数变化对试验用欧Ⅳ柴油机动力性、燃油经济性和缸内燃烧过程影响很小;微粒中的硫酸盐和气态SO2排放量均随硫含量上升而线性增加;十六烷值增加,比油耗和PM排放稍有下降、NOx排放稍有上升;T90下降,NOx排放下降、PM有降低趋势.在试验数据基础上,拟合得到了试验用欧Ⅳ柴油机ESC循环SCR前NOx和PM排放量随柴油硫含量、十六烷值、蒸馏特性T90和芳香烃含量4个参数变化的预测公式.