生物柴油和乙醇混合燃料的微爆特性实验研究

为了探究乙醇和生物柴油混合燃料的液滴微爆特性,设计并建立了悬挂液滴燃烧的实验装置和实验系统,在管式加热炉内用高速摄影拍摄并记录液滴的变化过程,以此得到了液滴的直径变化和微爆延迟,实验结果表明燃料的组分变化对液滴的微爆表现和性质有显著的影响,在混合燃料中乙醇和生物柴油的含量接近相等时液滴的微爆表现最好。     

废弃油脂生物柴油掺水微乳化燃料燃烧和排放性能研究

利用废弃油脂制备生物柴油不仅具有可观的经济效益,而且具有良好的社会效益和环境效益．为研究生物柴油掺水微乳化的燃烧和排放性能,在同一台双缸四冲程直喷式柴油机上进行了对比试验,测量燃料的燃烧压力和排放浓度．研究结果表明：与生物柴油相比,生物柴油掺水微乳化燃料的峰值燃烧压力的相对高低随发动机负荷变化．在排放特性中,生物柴油掺水微乳化燃料的烟度和NOx排放量显著降低,这证明掺水微乳化燃料能够改善燃烧状况,控制柴油机主要污染物排放．     

纳米流体在微通道换热中的研究进展

随着微尺度应用需求日益增长,纳米流体与微通道分别作为强化传热流动介质与强化传热结构获得学者们的广泛关注。主要概述了纳米流体的制备方法与稳定性,以纳米颗粒及基液类型、纳米颗粒的浓度、粒径以及强化传热机理为类别,综述了纳米流体在不同结构微通道中传热与流动性能的研究进展。通过分析已发表的研究成果,总结了纳米流体在微通道换热中的研究难点,提出了研究纳米流体在微通道中流动与传热特性的主要方向。     

纳米流体强化导热系数机理初步分析

从添加纳米粒子改变了液体结构和纳米粒子微运动两个方面,分析了纳米流体强化导热系数的机理,研究表明,相对于在液体中添加毫米或微米级固体粒子以增加导热系数而言,纳米流体强化导热系数的原因主要来自于纳米粒子的微运动,通过测量不同温度下纳米流体的导热系数,验证了纳米粒子微运动是纳米流体强化导热系数的主要因素。     

生物燃料在我国公路交通中替代潜力分析

首先从我国生物燃料开发的资源保障性、生产的技术经济性以及现代汽车技术利用的可能性等方面,对生物燃料的开发利用潜力进行了分析。之后重点论述了利用IPAC模型研究我国未来公路交通能源需求以及生物燃料替代的发展情景。研究表明:未来我国公路交通倍增的油品需求对我国石油供应造成巨大压力,推广新型汽车技术和发展替代燃料是降低公路交通油品消耗的战略措施,混合动力汽车技术与生物燃料结合是我国未来公路交通最佳的技术选择,并且生物燃料在我国未来公路交通中将展现出很强的燃料替代前景。     

有关微坑缸套中微坑参数优化的研究

对微坑式缸套内表面进行了微观分析,运用流体动压润滑理论建立了微坑缸套-活塞环润滑理论的数学模型,并应用有限差分法和超松弛迭代法对此求解,最后应用数值分析的方法在理论上对微坑的微观几何形貌和分布特,点等参数进行了优化.相关实验表明,微坑参数优化情况完全达到了相关要求,证明了使用微坑缸套能明显减少缸套和活塞环的磨损、机油耗量和有害物排放量.     

生物柴油发动机NOx排放控制技术

控制生物柴油发动机NOx的排放是目前生物柴油应用研究领域的一个研究热点和难点。根据NOx生成的条件和关键化学反应方程式,阐述了生物柴油发动机较柴油机NOx排放偏高的机理,在分析目前国内外降低生物柴油发动机NOx排放的各种控制策略和技术方法的基础上,重点介绍了针对生物柴油特殊的分子结构所采取的燃料改性的方法,对该方法的理论依据、国内外最新的研究成果和研究结论进行了阐述,分析了降低生物柴油发动机NOx排放的各种控制策略的优缺点,探讨了生物柴油发动机NOx排放控制技术的发展前景。     

原料供应困扰中国生物燃料产业发展

日前中国生物燃料考察组前往美国和巴西，进行了生物燃料技术和市场应用考察。 通过走访相关部门和企业了解到，目前美国的燃料乙醇生产是以玉米为主要原料，生物柴油则是以转基因大豆为主要原料，其原料供给能够满足生物燃料生产需求；巴西燃料乙醇生产是以甘蔗为原料．生物柴油的原料品种更多，其原料供给适应巴西的自然条件。     

CG125发动机燃用生物燃料(醇燃料)初探

生物燃料是清洁能源,目前,生物燃料主要指醇类燃料。首先简要介绍了醇类燃料的性质、国内外研究以及使用醇类燃料的现状;然后,选择目前国内生产量和保有量最大的小型发动机(排量125 mL)——CG125发动机为研究对象,探讨醇类燃料在该机中应用的技术方案,以及推广应用的途径。     

微藻规模化生产的关键问题

随着我国航空业的快速发展,航空碳减排形势严峻。航空生物燃料因其良好的减排性成为航空煤油的理想替代燃料,作为主要原料的微藻因具有产油率高、适应性强等优势,成为最有潜力的航空生物燃料原料。文章根据航空生物燃料产业化发展对于原料的选择和要求,探讨了富油高产微藻藻种的选育、规模化生产培养方式的选择、采收技术的改进、微藻航空生物燃料生产成本的降低以及微藻规模化生产适宜区域选择等关键问题,以寻求解决微藻实现规模化生产的路径,并提出相关建议,为中国以微藻为原料生产航空生物燃料产业发展提供参考。     

Biofuel production: Prospects,challenges and feedstock in Australia

The growing demands for energy coupled with ever increasing environmental concerns have allowed the global production of biofuels to rise significantly in recent years. Many countries across the world have begun utilising biofuels on a national scale, while many more are in the process of planning and implementing similar steps. While Australia has an abundance of fossil fuels in the form of coal, natural gas, and oil, and currently employs a variety of alternative energy sources, the technology to produce and implement biofuels in Australia is in its embryonic stage. Today, Australia is using first generation feedstock as the main source for the production of biofuel, but is progressively broadening into second-generation biofuel production technology. Australia has an enormous amount of biomass available in the form of agricultural and forestry residues, bagasse and feedstock currently unused for the production of biofuels. The technology for the conversion of lignocellulosic biomass into biofuels warrants further research to maximise yield to the point of industrial feasibility. This review discusses the current state of ethanol production in Australia, the key technological challenges involved in the production of second-generation biofuel and the availability of various kinds of lignocellulosic biomass for biofuel production.     

State-of-the-art in bioresources for sustainable transportation

Achieving circularity in the transportation sector is the strongest need of the hour and one of the pathways to achieve this is by embracing sustainable bio-energy resources. Considering this need, we investigated and reviewed the state-of-the-art readiness of the current bioresources i.e., biofuels. We provide a fresh overview of various biofuels (bioethanol, biohydrogen, biodiesel) production pathways followed by the landscape of current global production and consumption. In these discussions, we alluded to the prospects of algae-derived biofuels together with the techno-commercial aspects of biofuels toward achieving competitiveness in costs, technology and system design. The review also discussed the limitations of existing batteries over biofuel cell technology in terms of vehicle weight, storage capacity, cost and greenhouse pollution. Next, we discussed the advancement in biofuel cells (BFCs) and the challenges to the successful implantation of biofuel cells in the automotive sector. The development of a new e-biofuel cell system infrastructure was also elaborated to reduce the existing BFCs current problems and their environmental-economical sustainability was discussed. The review concluded by summarizing the current market scenario, global forecast for green energy resources and future directions in the area.     

Microfluidic fuel cells: A review

A microfluidic fuel cell is defined as a fuel cell with fluid delivery and removal, reaction sites and electrode structures all confined to a microfluidic channel. Microfluidic fuel cells typically operate in a co-laminar flow configuration without a physical barrier, such as a membrane, to separate the anode and the cathode. This review article summarizes the development of microfluidic fuel cell technology, from the invention in 2002 until present, with emphasis on theory, fabrication, unit cell development, performance achievements, design considerations, and scale-up options. The main challenges associated with the current status of the technology are provided along with suggested directions for further research and development. Moreover, microfluidic fuel cell architectures show great potential for integration with biofuel cell technology. This review therefore includes microfluidic biofuel cell developments to date and presents opportunities for future work in this multi-disciplinary field.     

Biofuel cell nanodevices

Looking at the past decades, intense efforts have been made on one of the flourishing technology called biofuel cells with respect to the power or energy crisis prevailing all over the globe. Global researchers are taking part in the development of biofuels cells by exploiting novel characteristics of unconventional materials at atomic and molecule level like nanotubes (carbon nanotubes), nanosheets, nanoparticles, conducting polymers, etc in order to generate effective electricity from the substrates of biological origin via utilizing various biocatalysts. With the advancement in the field of nanotechnology, significant discoveries with respect to the field of biofuel cells have been accomplished. But till date, there has been a significant challenge regarding the performance and efficiency of the biofuels cells. Nowadays, to generate high power, an efficient and skillful approach which consists of the implementation of nano-based materials and conducting polymers with respect to the assembly of the biofuel cells is being considered by many researchers. Bioenergy and biofuels is a potential contestant for alternative fuel and with regard to this nanotechnology is one such significant weapon to synthesize and modify the production of biofuel and bio-energy. It has been assumed that in the near future with such extensive research biofuel cells will take up the economy of a nation in a sustainable way. This review gives the insights of biofuel cells and their types, brief synopsis of applications of the biofuel cells along with the scrutiny of biofuel cells in the market. Significant discussions have been provided in this review relating to the nanomaterials being employed as an electrode in biofuel cells. Certain examples have been mentioned to justify the concept of biofuel cell nanodevices following the ethical considerations of the same.     

Black liquor gasification—consequences for both industry and society

The pulp and paper industry consumes large quantities of biofuels to satisfy process requirements. Biomass is however a limited resource, to be used as effectively as possible. Modern pulping operations have excess internal fuels compared to the amounts needed to satisfy process steam demands. The excess fuel is often used for cogeneration of electric power. If market biofuel availability at a reasonable price is limited, import/export to/from a mill however changes the amount of such biofuel available for alternative users. This work compares different mill powerhouse technologies and CHP plant configurations (including conventional recovery boiler technology and black liquor gasification technology) with respect to electric power output from a given fuel resource. Different process steam demand levels for different representative mill types are considered. The comparison accounts for decreased/increased electricity production in an alternative energy system when biofuel is imported/exported to/from the mill. The results show that black liquor gasification is in all cases considered an attractive powerhouse recovery cycle technology. For moderate values of the marginal electric power generation efficiency for biofuel exported to the reference alternative energy system, excess mill internal biofuel should be used on mill site for gas turbine based CHP power generation. The remaining excess biofuels in market pulp mills should be exported and used in the reference alternative energy system in this case. For integrated pulp and paper mills, biofuel should be imported, but only for cogeneration usage (i.e. condensing power units should be avoided). If biofuel can be used elsewhere for high efficiency CHP power generation, mill internal biofuel should be used exclusively for process heating, and the remainder should be exported.     

Virtual biofuels—A cheaper,better, faster alternative?

This viewpoint article offers the proposition that purpose-grown biomass buried in landfills constitutes a “virtual” biofuel that is more practical, economic, and immediate than the use of actual biofuels from cellulosics. While not a permanent solution, it may be a useful bridge to the hoped-for era of actual biofuels prior to the time technology for economically converting cellulosics to actual liquid biofuels is realized.     

Global land-use implications of first and second generation biofuel targets

Recently, an active debate has emerged around greenhouse gas emissions due to indirect land use change (iLUC) of expanding agricultural areas dedicated to biofuel production. In this paper we provide a detailed analysis of the iLUC effect, and further address the issues of deforestation, irrigation water use, and crop price increases due to expanding biofuel acreage. We use GLOBIOM – an economic partial equilibrium model of the global forest, agriculture, and biomass sectors with a bottom-up representation of agricultural and forestry management practices. The results indicate that second generation biofuel production fed by wood from sustainably managed existing forests would lead to a negative iLUC factor, meaning that overall emissions are 27% lower compared to the “No biofuel” scenario by 2030. The iLUC factor of first generation biofuels global expansion is generally positive, requiring some 25 years to be paid back by the GHG savings from the substitution of biofuels for conventional fuels. Second generation biofuels perform better also with respect to the other investigated criteria; on the condition that they are not sourced from dedicated plantations directly competing for agricultural land. If so, then efficient first generation systems are preferable. Since no clear technology champion for all situations exists, we would recommend targeting policy instruments directly at the positive and negative effects of biofuel production rather than at the production itself.     

How much hope should we have for biofuels?

This paper revisits the recent developments in biofuel markets and their economic, social and environmental impacts. Several countries have introduced mandates and targets for biofuel expansion. Production, international trade and investment have increased sharply in the last few years. However, some analysts linked biofuels to the 2007-2008 global food crisis. Existing studies diverge on the magnitude of the projected long-term impacts of biofuels on food prices and supply, with studies that model only the agricultural sector showing higher impacts and studies that model the entire economy showing relatively lower impacts. In terms of climate change mitigation, biofuels reduces GHG emissions only if GHG emissions related to land-use change are avoided. When biofuel production entails conversion of forest to cropland, net reduction of GHG would not be realized for many years. Existing literature does not favor the diversion of food for large-scale biofuels production, but the regulated expansion of biofuels in countries with surplus lands and a strong biofuel industry cannot be ruled out. Developments in non-food based or cellulosic (or second generation) biofuels may offer some hope, yet they still compete with food supply through land use and are currently constrained by a number of technical and economic barriers.     

Indirect land use change and biofuels: Mathematical analysis reveals a fundamental flaw in the regulatory approach

In the Renewable Fuel Standard (RFS2) program, the United States Environmental Protection Agency (U.S. EPA) has used partial equilibrium models to estimate the overall indirect land use change (iLUC) associated with the biofuel scenario mandated by the Energy Independence and Security Act of 2007 (EISA). For regulatory purposes, the U.S. EPA “shocks” (changes) the amount of each biofuel in the economic models one at a time to estimate the threshold values for specific biofuels (single-shock analysis). The primary assumption in the single-shock analysis is that iLUC is a linear process with respect to biofuels, i.e., that interactions between different biofuels are trivially small. However, the assumption of linearity in the single-shock analysis is not appropriate for estimating the threshold values for specific biofuels when the interactions between different biofuels are not small.Numerical results from the RFS2 program show that the effects of interactions between different biofuels are too large to be ignored. Thus, the threshold values for specific biofuels determined by the U.S. EPA are scenario-dependent and value choice-driven. They do not reflect real impacts of specific biofuels. Using scenario-dependent values for regulation is arbitrary and inappropriate. Failure to deal appropriately with interactions between different biofuels when assigning iLUC values to specific biofuels is a mathematical and systematic flaw; it is not an “uncertainty” issue. The U.S. EPA should find better ways to differentiate the contribution of one biofuel versus another when assigning iLUC values or find better means of regulating the land use change impact of biofuel production.