生物质固体成型燃料全生命周期评价

为探讨生物质固体成型燃料的能源效率和温室气体排放量,采用全生命周期评价分析原理,对北京地区以玉米秸秆为原料的生物质固体成型燃料进行全生命周期分析.结果表明:生物质固体成型燃料的净能量为13243.5MJ/t,能量产出投入比为10.8,其中,种植阶段、加工阶段以及秸秆运输能源消费居前三位,分别占总量的58.65％、24.23％、12.58％.CO2当量排放量为11.13g/MJ,约为煤的1/9.这说明生物质固体成型燃料具有较大的节能、减少温室气体排放的效益.     

车用甲醇汽油的生命周期能源消耗与温室气体排放分析

结合生命周期评价原理,对煤制甲醇与原油制汽油混合而成的甲醇汽油路线的能源消耗与温室气体排放进行生命周期分析。发现煤气化方法对甲醇路线影响较大,燃料的制造环节所消耗的能源与产生的温室气体占全生命周期相应指标的比例均超过50%。在所考虑的四种煤气化方法中,谢尔法的一次能源消耗与温室气体排放最低。若考虑车辆技术的进步,甲醇汽油路线的一次能源消耗可比传统汽油路线降低9%,温室气体排放量仅增加3.5%。此外,分析结果还表明利用煤制甲醇来代替部分传统汽油,每投入1.8t原煤便可以节省1.0t原油。由于我国的能源生产以煤为主,故以甲醇代替汽油的策略既能有效缓解我国对原油进口的依赖,又不会对能源生产造成明显压力。     

生物质热解提质燃油全生命周期评估分析

运用GREET分析软件对新兴车用替代燃料——生物质热解提质燃油进行全生命周期分析,得到工艺路线不可再生能耗为0.295 MJ/MJ,温室气体排放为25.05 g二氧化碳当量,两项指数均远低于传统汽柴油,略优于其他生物质基燃料。热解提质制油工艺中生物原油改性提质过程为最大的能耗源与GHG排放源,各占整个工艺流程的40.28%和42.49%。     

百吨级生物质混合醇系统能耗和温室气体排放分析

以农林废弃生物质气化合成混合醇工艺为对象,利用混合生命周期评估方法对百吨级系统进行环境影响分析。通过构建系统的工艺模型和收集生命周期资源消耗及排放清单,研究农林业、收储运和制取等各阶段的投入和排放特性,对棉秆、玉米秸秆、木屑和枝丫柴4种原料制取系统的环境影响特性进行分析,并与5万吨级系统进行比较。结果表明：百吨级系统生命周期化石能源消耗和温室气体排放分别在589～734 kJ/MJ混合醇和63.2～80.8 g CO₂eq/MJ混合醇范围内,制取阶段的电力消耗是最主要的影响因素,其次为系统设备设施投入,玉米秸秆混合醇的环境影响最大,这与原料碳含量低及混合醇收率低有关。     

秸秆直燃发电系统的生命周期评价

以装机容量25 MW的生物质秸秆直燃发电系统为评价对象,进行生命周期评价.结果表明,秸秆直燃发电1万kWh,可吸收CO2 2502.87 kg,向环境排放SO237.39 kg,NOx90.37 kg,与燃煤发电相比,虽然氮氧化物的排放量有所增加,但减少了温室气体及硫氧化物的排放,污染物的排放主要发生在秸秆燃烧阶段.每发电1万kWh消耗能量15 340.2 MJ,秸秆预处理阶段是能量消耗的主要阶段,须要输入能量13 830.5MJ.秸秆直燃发电过程对环境影响的总负荷为35.18人当量.在此过程中,烟尘居环境影响总负荷的首位.     

生物燃料乙醇和生物柴油全生命周期分析

使用清华大学Tsinghua-CA3EM模型中的Well-to-Wheels模块,对玉米、木薯、甜高粱制取燃料乙醇和大豆、麻风果、地沟油制取生物柴油共6条技术路线,进行了基于案例的全生命周期计算。结果表明:除木薯制乙醇路线外,其它各路线的化石能源投入都大于所产燃料所含的能量;与汽油、柴油路线相比,各生物燃料路线所需的化石能源减少、温室气体排放增加;导致此状况的原因主要为燃料生产能耗高、原料种植过程中肥料消耗多等。综合考虑,对于富煤贫油国情而言,现有生物燃料路线具有可行性。     

惠州市工业源温室气体排放清单研究

根据收集到的惠州市活动水平数据,参照IPCC(2006)指南,建立了惠州市工业源温室气体排放清单。结果显示:2017年惠州市工业源温室气体排放总量为9 164.9万t CO2e,大亚湾地区贡献最高,占86.39%,石油加工、炼焦及核燃料加工业行业贡献最大,占60.68%,原油燃料排放最大,占47.6%。     

车用沼气燃料生命周期的评价

利用国际标准化组织的生命周期评价(LCA)标准,确定了城市垃圾厌氧发酵车用沼气燃料的生命周期评价的边界和清单分析参数,提出了生命周期清单分析(LCI)的计算方法,对垃圾厌氧发酵车用沼气燃料进行了生命周期评价.结果表明:在车用沼气燃料生命周期中,改善厌氧发酵过程是减少能源消耗的主要途径;沼气车辆运行阶段是影响环境污染物排放的关键;全球变暖对环境影响负荷贡献最大.城市垃圾厌氧发酵为城市垃圾的处理找到了可持续发展的途径.     

纳米有机工质ORC系统的生命周期评价研究

基于生命周期评价(LCA)方法,对32 kW Al_2O_3/R141b纳米有机工质ORC系统整个生命周期的物料和能源投入、环境影响、总能量消耗以及能量回收期进行计算,从贡献、敏感性以及改进3个角度对其进行分析,最后比较了不同发电系统对环境的影响。结果表明:32 kW Al_2O_3/R141b纳米有机工质ORC系统的生命周期总能量消耗为24360.50 MJ,能量回收期只占系统使用寿命的1.03%;制造阶段综合环境影响最大,其中ORC部件生产过程综合环境影响贡献最大;优化系统工况、改进部件结构和探寻传热性能更好的纳米有机工质是降低环境负荷的主要方向;用纳米有机工质ORC系统发电具有明显的环境优势。     

福建省能源活动温室气体排放测算及其碳强度趋势

根据《省级温室气体清单编制指南(试行)》,福建省能源活动温室气体包括化石燃料、生物质燃料燃烧活动产生的CO2、CH4和N2O排放及煤矿和矿后活动、石油和天然气系统产生的CH4逃逸排放。界定福建省能源活动过程温室气体的排放源及温室气体种类;给出各排放源相关的温室气体排放量估算方法,确定活动水平数据及排放因子,并估算各排放源温室气体的排放量;汇总化石燃烧排放的CO2量,化石燃料燃烧、生物质燃料燃烧、煤炭开采和矿后活动逃逸、石油和天然气系统逃逸排放的CH4量,化石燃料燃烧和生物质燃料燃烧排放的N2O量;生成福建省能源活动温室气体清单汇总,并根据福建省地区生产总值GDP得出碳强度趋势。     

加氢裂化装置用能分析及节能措施

中国石化广州分公司1.2Mt/a加氢裂化装置由洛阳石化工程公司设计,采用抚顺石油化工科学研究院开发的FF-26/FC-26一段串联全循环加氢裂化工艺流程,装置开工后能耗一直处于较高水平。通过对能耗组成分析,发现装置实际能耗中电耗占46%～49%,燃料消耗占23%～29%,蒸汽消耗占14%～16%,与设计值差距较大。通过对装置高压贫胺液泵更换小叶轮、新氢压缩机应用Hydro COM气量调节系统,采取原料热进料,提高新氢纯度等节能改造,以及维持适宜氢油体积比(约为1000),降低热高压分离器和分馏进料加热炉温度,降低主汽提塔压力,提高装置负荷率等优化措施,装置能耗从2008年的1523MJ/t降低到2010年的1150MJ/t。同时指出,加氢裂化装置下一步可以通过增加变频电机、实施低温热利用、采用旋流脱烃等措施进一步降低能耗。     

延迟焦化装置能耗分析及优化措施

克拉玛依石化公司1.5Mt/a延迟焦化装置加工原料为稠油,于2004年建成投产。装置包括电脱盐和脱钙系统、焦化系统、富气压缩吸收稳定系统三大部分,设计能耗为1798.02MJ/t原油,但2005年装置实际能耗为1967.70MJ/t原油,远超出设计值。该装置能耗构成中,燃料气占55%以上,蒸汽占34%,耗电占10%以上。减少燃料气、电耗和蒸汽消耗是降低装置能耗的关键。为此,实施如下改造措施:①对加热炉余热回收系统进行水热媒技术改造,以高压脱氧水为传热介质,实现热烟气和冷空气之间的热量交换,保证热管表面温度均匀,改造后加热炉排烟温度降至166℃,热空气入炉温度升至267℃,热效率超过90%的设计值。②优化装置操作,减少3.5MPa和1.0MPa蒸汽消耗;降低吸收稳定系统压力和解析塔底、稳定塔底温度,增加自产蒸汽量。③优化除焦操作,缩短除焦时间,为空冷器电机安装变频系统,以降低电耗。④降低焦化装置新水和循环水消耗。节能措施实施后,2009年装置能耗为1067.31MJ/t原油,比设计值降低730.71MJ/t原油,折合燃料油为21.44kg标油/t原油。     

Wood pellets production costs and energy consumption under different framework conditions in Northeast Argentina

The development of cleaner and renewable energy sources are needed in order to reduce dependency and global warming. Wood pellets are a clean renewable fuel and has been considered as one of the substitutes for fossil fuels. In Argentina, large quantities of sawmill residues are still unused and wood pellets production could be seen as both, as an environmental solution and an extra economical benefit. The general aim of this study was to determine the wood pellets production costs and energy consumption under different framework conditions in northeast Argentina. The specific costs of wood pellets for the different scenarios showed relative lower costs comparing to the ones reported in other studies, ranging from 35 to 47 €/Mg_pellets. Raw material costs represented the main cost factor in the calculation of the total pellets production costs. A lower specific production cost was observed when 50% of the raw material input was wood shavings. The specific electricity consumption per metric ton of pellet was lower in scenarios with higher production rate. Lower heat energy consumption was observed in scenarios that have a mixed raw material input. The most promising framework condition for Northeast Argentina, in terms of costs effectiveness and energy consumption could be acquired with production rates of 6 Mg/h with sawdust and wood shavings as raw material. However, simultaneous increment of the electricity by 50% and raw material price by 100% may increase the specific costs up to 50%.     

Energy consumption analysis of integrated flowsheets for production of fuel ethanol from lignocellulosic biomass

Fuel ethanol is considered one of the most important renewable fuels due to the economic and environmental benefits of its use. Lignocellulosic biomass is the most promising feedstock for producing bioethanol due to its global availability and to the energy gain that can be obtained when non-fermentable materials from biomass are used for cogeneration of heat and power. In this work, several process configurations for fuel ethanol production from lignocellulosic biomass were studied through process simulation using Aspen Plus. Some flowsheets considering the possibilities of reaction–reaction integration were taken into account among the studied process routes. The flowsheet variants were analyzed from the energy point of view utilizing as comparison criterion the energy consumption needed to produce 1 L of anhydrous ethanol. Simultaneous saccharification and cofermentation process with water recycling showed the best results accounting an energy consumption of 41.96 MJ/L EtOH. If pervaporation is used as dehydration method instead of azeotropic distillation, further energy savings can be obtained. In addition, energy balance was estimated using the results from the simulation and literature data. A net energy value of 17.65–18.93 MJ/L EtOH was calculated indicating the energy efficiency of the lignocellulosic ethanol.     

Energy and cost analysis of organic fertilizer production in Nigeria

Energy study was conducted in an organic fertilizer production plant in Nigeria, to determine the energy consumption patterns and the associated costs for the production of both powdered and pelletised fertilizer. Analysis was conducted for a daily production of 9000 kg of the finished products. Eight and nine defined unit operations were required for production of powder and pellets, respectively. The electrical and manual energy required for the production of powder were 94.5 and 5.6% of the total energy, respectively, with corresponding 93.9 and 5.1% for the production of pellets. The respective average energy intensities were estimated as 0.28 and 0.35 MJ/kg for powder and pellets. The most energy intensive operation was identified as the pulverizing unit with energy intensity of 0.09 MJ/kg, accounting for respective proportions of 33.4 and 27.0% of the total energy for production of powder and pellets. The energy cost per unit production for powdered and pelletised fertilizer using generator were evaluated as ?2.92 ($0.021) and ?3.87 ($0.028), respectively, with corresponding values of ?1.65 ($0.012) and ?2.00 ($0.014) when electrical energy from the national grid was used. The energy intensities for the production of organic fertilizers were significantly lower than that of inorganic fertilizers.     

我国可再生能源发展对策

可再生能源的开发利用是应对气候变化和满足能源需求持续增长的最现实的举措。2009年我国风电和太阳能光伏发电保持了快速发展势头,其中风电装机容量估计达到约2200×104kW,但非化石能源消费量在能源消费总量中所占的比重仍然很低。2009年,我国能源消费总量约为31×108t标煤,其中水电、核电、风电等商品化非化石能源消费量约为2.3×108t标煤,约占能源消费总量的7.4%。要完成到2020年我国非化石能源在能源消费总量中所占比例达到15%的目标,任务非常艰巨。加快开发利用可再生能源是能源发展的重要任务之一,到2020年,可再生能源开发利用总量将在2008年的基础上增加2倍以上。我国目前和今后10多年时间内,可再生能源发展的重点是水电、风电、太阳能和生物质能。加快发展我国可再生能源的举措有:①继续做好水电建设工作,促进水电持续健康发展;②有序推进风电的规模化发展,显著提高风电在电力结构中的比重;③加快推广太阳能利用技术,扩大太阳能开发利用规模;④因地制宜开发利用生物质能,提高生物质能利用的现代技术水平。     

Nanometallic fuels for transportation: a well‐to‐wheels analysis

Nanometallic iron and aluminium, along with hydrogen and electricity, are among the proposed alternatives to the petroleum‐based fuels for future transportation. The advantages of the metallic fuels appear to be high volumetric energy densities and zero greenhouse gas emissions during the operation of the vehicle. However, nanometallic fuels do not exist in nature, and a well‐to‐wheel analysis of the fuel manufacture‐utilization system is required to quantify the energy consumption and assess the true environmental impact of the proposed alternative. The three‐component nanometallic fuel system consisting of a metal production process, a nanoparticle formulation process and the metal combustion process is analysed in this paper. The energy balance and the environmental impact are estimated for nanometallic iron and aluminium based systems. The sustainability of once‐through systems that do not involve recycle of combustion products is questionable because of resource limitations. A viable system for satisfying the transportation fuel demands will involve the reduction and recycle of the combustion products. A comparison of these nanometallic fuels with gasoline and hydrogen indicates that nanometallic fuels are the least efficient, with primary energy consumption greater than 11 MJ km^?1 compared to 0.625 MJ km^?1 for gasoline and 8.6 MJ km^?1 for hydrogen. The nanometallic fuels will also have the most severe impact of the three, with CO₂‐equivalent emissions of 13.44 billion tons year^?1 for iron and 21.1 billion tons year^?1 for aluminium as compared to approximately 0.8 billion tons year^?1 for gasoline. These emissions from nanometallic fuels are at least an order‐of‐magnitude higher than those for gasoline and hydrogen. The results of the analysis emphasize the need for well‐to‐wheel assessment for determining the true impact of technologies proposed as replacements for the current technologies. Copyright © 2006 John Wiley & Sons, Ltd.     

对我国发展纯电动汽车的质疑与思考

近年来国家对纯电动汽车的扶持力度正在不断加大。然而纯电动汽车、混合动力汽车等以电力作燃料,并非真正意义上的新能源汽车。纯电动汽车所消耗的电力需要由发电厂提供,相当于以煤代油,其外部负效应表现在燃煤电厂的负效应上。燃油汽车和纯电动汽车每辆车每年的能耗折算成标煤分别为1.53t和1.6t,基本上相等,但燃油排放的二氧化碳比燃煤少,所以纯电动汽车并不是低碳汽车。用纯电动汽车替代燃油汽车,很可能是减少了石油进口,但却要增加煤炭进口,并不能从根本上提高我国能源的安全性。发展纯电动汽车需要大量投资,再加上环境污染,经济性很差。鉴于此,建议我国应重新定义新能源汽车,要真正利用新能源作为汽车的动力,寻找适合我国能源资源条件的真正的新能源汽车或替代能源汽车;中国在相当长的时间里节能减排还是主要依靠传统燃油汽车,在重视研发新能源汽车、研究替代燃油汽车的同时,应重视传统燃油汽车的节能降耗;控制汽车消费是最有效的节油措施;节能减排必须要从一次能源算起,我国电源结构以煤电为主,并不适宜发展纯电动汽车。中国要等到第一次和第二次能源大转换完成之后,当天然气、水电、核电在电源结构中占据主体地位时,纯电动汽车才会有广阔的发展前景。     

催化汽油质量升级方案比较

结合某炼油厂汽油调合组分现状,提出两种汽油质量升级方案,即:催化汽油只进行加氢脱硫处理(方案一),以及在方案一的基础上增设轻汽油醚化部分(方案二)。确定以Axens公司的Prime-G+技术作为方案一选用的催化汽油加氢脱硫技术,以CDTECH公司的醚化技术作为方案二选用的醚化工艺。调合结果显示,采用方案一,全厂汽油平均硫含量为18.95g/g,可全部生产京Ⅳ或欧Ⅳ标准汽油。但加氢脱硫处理造成辛烷值损失,致使97号京Ⅳ标准汽油产量仅为6.61×104t/a,约占汽油总产量的3.73%。经方案二处理后,全厂汽油调合性质同样满足京Ⅳ或欧Ⅳ标准要求,且97号京Ⅳ标准汽油产率由方案一的3.73%提高至22.64%。公用工程方面,方案二的循环水、1.0MPa蒸汽耗量远高于方案一,其能耗(1524.56MJ/t原料)是方案一能耗(745.12MJ/t原料)的约2倍,总投资也高于方案一。但方案二每年可消耗5.47×104t甲醇,将这部分价格较低的甲醇通过醚化转化为高附加值的汽油产品,按目前价格计算,每吨甲醇可升值约4000元。项目实施后,财务内部收益率(税后)、吨油净利润分别达到30.81%和103.60元/t,远高于方案一的8.80%和13.86元/t。综合比较,确定该厂催化汽油升级方案采用方案二。