不同排放标准公交车燃用生物柴油颗粒物排放特性

基于重型底盘测功机,对比研究了满足国Ⅲ、国Ⅳ、国Ⅴ排放标准的柴油公交车分别燃用生物柴油与柴油混合燃料B0/B5/B10在中国典型城市公交车循环下的颗粒物排放特性.结果表明燃用B0/B5/B10时,国Ⅴ车相对国Ⅲ车总颗粒数量和质量排放分别降低约68.1%、56.2%、57.5%和52.7%、64.8%、88.5%,相对国Ⅳ车,总颗粒质量排放分别降低了约43.0%、47.3%和42.1%,但数量排放分别上升了约4.0%、7.6%和14.7%.国Ⅲ车核态颗粒排放主要来自高速行驶工况,而国Ⅳ、国Ⅴ车主要来自中低速行驶工况;国Ⅲ、国Ⅳ、国Ⅴ车聚集态颗粒排放主要都来自中低速行驶工况.其中在车速较低时,国Ⅴ、国Ⅳ车相对国Ⅲ车核态颗粒数量和质量排放明显降低,聚积态颗粒也有降低,但国Ⅴ车相对国Ⅳ车改善不明显,核态颗粒数量和质量排放反而增加,且随着生物柴油掺混比例的上升,增幅越明显.在高速时,国Ⅲ车核态颗粒数量和质量排放急剧增加,国Ⅴ、国Ⅳ车略有增加,且国Ⅳ车聚集态颗粒数量和质量排放明显大于国Ⅴ车和国Ⅲ车.燃用生物柴油掺混比例较大的B10时,国Ⅲ车较大粒径颗粒排放急剧恶化,聚集态颗粒数量和质量排放大幅增加,不适合推广应用较大生物柴油掺混比燃油.     

麻疯树种子油生命周期的经济、环境与能量效率

要成为化石能源的有效替代品，生物燃料必须能提供净能量收益，能产生环境效益，具有经济效率，且在大量生产的情况下不引起粮食危机。麻疯树作为第二代生物柴油的重要原料作物，在国内得到大力推广，但实际效率尚不清楚。基于将麻疯树种子油与化石柴油直接混合使用的技术选择，利用生命周期评估法分析了麻疯树种子油生命周期的经济、环境和能量效率。结果表明：（1）在当前产量和生产技术水平下，生产和使用麻疯树种子油的财务净现值为负，要促进麻疯树种子油的生产，需要每年为种子生产者提供8817 元/hm2以上的补贴，为榨油厂商提供268 元/L的补贴；（2）生产和使用每升麻疯树种子油可减少约13 kgCO2当量的温室气体排放，固碳价值为补贴生产提供了部分经济依据，但是仅考虑种子油和固碳的价值时，生产和使用麻疯树种子油尚不具有经济可行性；（3）当仅考虑种子油的能量产出时，只有当种子产量达到795 kg/hm2以上才具有能量效率；当把树枝和果壳等所包含的生物质能计算在内时，在较低种子产量的情况下，也具有显著的能量效率。敏感性分析表明，随着麻疯树种子产量的增加，财务净现值趋于下降，但是种子油的成本下降，减排温室气体的贡献和能量效率都增加。最后，基于麻疯树种子油的生命周期分析，提出了提高经济、环境和能量效率的途径。〖     

Experimental investigation of diesel engine using EGR and fuelled with Karanja oil methyl ester

Karanja oil methyl ester (KOME), a biodiesel prepared from Karanja oil, a potential source of non-edible oil in India and a prospective alternative to the diesel fuel, shows comparable performance and considerable reduction in emissions except NO_x. Exhaust gas recirculation (EGR) is a popular method of reducing the NO_x emission. The aim of this experimental work was to study the potential of the cooled EGR in a direct injection compression ignition engine operating with the KOME and its blend. The study was conducted with the different EGR rates. Performance and emission parameters were compared by using diesel, KOME and its blend employing EGR and with the same fuels without EGR. The study also differentiates the effect of EGR on KOME and its blend with the neat diesel. The effect of EGR was found to be slightly higher for KOME biodiesel and its blend than for neat diesel. Increased NO_x emission using KOME biodiesel was also found to be reduced by using EGR.     

燃用生物柴油对柴油机颗粒生成和排放特性研究进展

为深入研究生物柴油对柴油机颗粒排放的影响,在总结国内外相关研究进展的基础上,通过研究生物柴油的化学组成和物理特性,讨论了生物柴油产生颗粒的特殊性及其对环境的影响.在此基础上,从PAHs（polycyclic aromatic hydrocarbons,多环芳烃）的形成途径角度简要分析了生物柴油颗粒形成的机理,并从生物柴油的3个关键性质入手,分析了其对颗粒排放的规律和影响.最后,以实际柴油机运行时的5项参数为基础,讨论柴油机实际使用生物柴油对颗粒排放的影响.结果表明:①不同材料和产地生物柴油的理化特性和对颗粒排放的影响有很大不同,但总体有利于减少对人体和环境的有害排放.②生物柴油将改变颗粒形成过程中半挥发性物质在微晶核表面的吸附,富氧作用也使燃烧热解后生成的颗粒尺寸更小,减少40%~50%;同时,纳米结构上的变化增加了生物柴油颗粒的反应活性,形成了更多30 nm以内的核态模式颗粒,更容易被人体吸收.③脂肪酸链的长度、不饱和度和含氧量对生物柴油颗粒排放量的减少发挥了重要作用,而柴油机参数的不同也对生物柴油的颗粒排放十分重要.④生物柴油对颗粒生成机理的关键在于复杂的含碳前驱物的生成路径.使用生物柴油总体上可减少前驱物的排放量,其主要成分为四元环和五元环,占总排放量的58.70%以上,但苯并蒽和?分别上升了44%和340%.研究显示,柴油机燃用生物柴油对颗粒排放有积极的一面,但在超细颗粒和某些特定前驱物控制上仍需引起高度重视.      

产油微藻胁迫培养策略研究综述

围绕微藻的胁迫培养,介绍了不同胁迫手段影响下产油微藻的生长及产油特点,对比了不同胁迫手段下微藻产油效果及各手段优劣势,在此基础上进一步综述了各因素胁迫在微藻油脂合成代谢中的作用机理,并给出了各胁迫手段在实际生产中的选用建议.以期通过该综述,对微藻生物柴油产业化中相关胁迫策略的选择提供借鉴.     

Bacterial Poly(Hydroxyalkanoate) Polymer Production from the Biodiesel Co-product Stream

A co-product stream from soy-based biodiesel production (CSBP) containing glycerol, fatty acid soaps, and residual fatty acid methyl esters (FAME) was utilized as a fermentation feedstock for the bacterial synthesis of poly(3-hydroxybutyrate) (PHB) and medium-chain-length poly(hydroxyalkanoate) (mcl-PHA) polymers. Pseudomonas oleovorans NRRL B-14682 and P. corrugata 388 grew and synthesized PHB and mcl-PHA, respectively, when cultivated in up to 5% (w/v) CSBP. In shake flask culture, P. oleovorans grew to 1.3 ± 0.1 g/L (PHA cellular productivity = 13–27% of the bacterial cell dry weight; CDW) regardless of the initial CSBP concentration, whereas P. corrugata reached maximum cell yields of 2.1 g/L at 1% CSBP, which tapered off to 1.7 g/L as the CSBP media concentration was increased to 5% (maximum PHA cellular productivity = 42% of the CDW at 3% CSBP). While P. oleovorans synthesized PHB from CSBP, P. corrugata produced mcl-PHA consisting primarily of 3-hydroxyoctanoic acid (C_8:0; 39 ± 2 mol%), 3-hydroxydecanoic acid (C_10:0; 26 ± 2 mol%) and 3-hydroxytetradecadienoic acid (C_14:2; 15 ± 1 mol%). The molar mass (M_n) of the PHB polymer decreased by 53% as the initial CSBP culture concentration was increased from 1% to 5% (w/v). In contrast, the M_n of the mcl-PHA polymer produced by P. corrugata remained constant over the range of CSBP concentrations used.     

生物柴油的研究与应用

介绍了生物柴油的特点和性质以及主要的生产方法；综述了生物柴油的国内外研究、生产现状和发展趋势；分析了发展生物柴油对中国石油安伞、国民经济建设、农业产业结构调整和环境保护的作用；并展望了该产业的发展前景。     

CO<Subscript>2</Subscript> Mitigation and Renewable Oil from Photosynthetic Microbes: A New Appraisal

The only major strategy now being seriously considered for biological mitigation of atmospheric CO₂ relies entirely on terrestrial plants. Photosynthetic microbes were the focus of similar consideration in the 1990s. However, two major government-sponsored research programs in Japan and the USA concluded that the requisite technology was not feasible, and those programs were terminated after investing US$117 million and US$25 million, respectively. We report here on the results of a privately funded US$20 million program that has engineered, built, and successfully operated a commercial-scale (2 ha), modular, production system for photosynthetic microbes. The production system couples photobioreactors with open ponds in a two-stage process – a combination that was suggested, but never attempted – and has operated continuously for several years to produce Haematococcus pluvialis. The annually averaged rate of achieved microbial oil production from H. pluvialis is equivalent to <420 GJ ha ^-1 yr^-1, which exceeds the most optimistic estimates of biofuel production from plantations of terrestrial ``energy crops.' The maximum production rate achieved to date is equivalent to 1014 GJ ha^-1 yr^-1. We present evidence to demonstrate that a rate of 3200 GJ ha^-1 yr^-1 is feasible using species with known performance characteristics under conditions that prevail in the existing production system. At this rate, it is possible to replace reliance on current fossil fuel usage equivalent to ∼300 EJ yr^-1 – and eliminate fossil fuel emissions of CO₂ of ∼6.5 GtC yr^-1 – using only 7.3% of the surplus arable land projected to be available by 2050. By comparison, most projections of biofuels production from terrestrial energy crops would require in excess of 80% of surplus arable land. Oil production cost is estimated at $84/bbl, assuming no improvements in current technology. We suggest enhancements that could reduce cost to $50/bbl or less.     

核桃果皮基磁性固体酸催化剂的制备及其催化性能研究

采用自底向上策略,利用农业废弃物核桃青果皮制备了磁性碳质固体酸催化剂,并对其进行了BET、XRD、SEM、IR和TGA等表征分析.结果表明,合成的磁性固体酸催化剂结构蓬松,比表面积大,具有良好的热稳定性.催化剂MPCs-0.2-SO₃H在生物柴油的合成中具有良好的催化活性.当醇油比为30,催化剂加入量为油酸质量的7%,80℃反应8 h酯化率达到74.2%,比商用Amberlyst-15催化剂的酯化率高近20%,最高含水量可达油酸质量的4%,重复使用3次后仍具有较高的酯化率,不仅实现了废弃物的资源化,而且得到的催化剂磁性易分离,在生物柴油的合成中具有巨大的应用潜能.     

燃用生物柴油对采用CRPT技术的柴油机微粒粒子数浓度和PAHs排放的影响

微粒和PAHs是柴油机排放污染物的重要组成部分,为揭示燃用生物柴油（biodiesel,下称BD）与采用CRPT（连续再生微粒捕集系统,continuous regeneration particulate traps system）技术后对柴油机排放中微粒粒子数浓度和PAHs组分质量的影响规律,利用内燃机综合测试台架对3台排量不同的柴油机进行微粒以及PAHs测试,研究不同微粒粒径对应的粒子数浓度变化规律以及PAHs各组分的质量变化规律.结果表明:①燃用BD对柴油机微粒排放中的聚集态粒子数浓度和总质量影响较大,对核态粒子数浓度影响不大,其中,聚集态粒子总质量降幅最大可达97.04%,粒子数浓度最大降幅从109 m-3降至106 m-3,而核态粒子数浓度变化不大,但粒子数比例有明显的上升,最大升幅为51.50%.②燃用BD对微粒排放中不同粒径粒子数浓度的影响导致CRPT技术条件下微粒质量捕集效率下降,最大降幅达21.10%.③PAHs总质量排放有明显下降,3台柴油机最大降幅分别为92.95%、91.78%和92.70%.但各组分呈现变化不一致现象,类似于二苯并蒽等部分组分质量下降幅度均达到100%,而和苯并蒽的质量均不降反升,其中的质量占燃用BD30后的多环芳香烃质量的50%左右.研究显示,采用"BD+CRPT"技术,柴油机微粒排放控制焦点应集中在核态微粒,PAHs排放的控制还应侧重于考虑和苯并蒽.