甲醇气相催化脱水制二甲醚新技术

1前言 二甲醚是一种含氧化合物，溶于水，在大气对流层中可降解，是环境友好介质。二甲醚可用作气雾剂、制冷剂、化工原料。二甲醚可做燃料，具有与液化石油气相类似的性质，而且燃烧完全、热效率高、无黑烟。近年来，由于石油制品的连年涨价，作为洁净环保燃料的二甲醚引起了社会各界的重视。特别是煤基二甲醚生产成本低，与液化石油气有较大差价，使得二甲醚全面替代液化石油气作为民用、工业用燃料成为可能。国内外多家研究机构也正在进行以二甲醚为燃料的汽车发动机研究乃至行车试验，由于二甲醚十六烷值高、燃烧尾气污染物少，是被业内人士看好的车用柴油的替代品。因此，二甲醚做燃料的市场前景十分广阔。同时，生产二甲醚也是当甲醇市场供大于求时甲醇生产企业的一条产业出路。     

浅析液化石油气中二甲醚的检测与管理策略

近几年来,我国乃至世界的油价都在不断增长,这对液化石油气也产生了影响,其价格也在不断上涨,而二甲醚作为一种清洁燃料成本与液化石油气相比非常低廉,因此,不断被掺入液化石油气中。本文分别详细的介绍了液化石油气及二甲醚,并指出在液化石油气中掺杂二甲醚所产生的危害,提出了相应的检测手段及管理策略。     

清洁燃料二甲醚

通过介绍液化石油气中二甲醚掺混问题产生的行业背景及相关标准的制定情况,说明了二甲醚作为替代液化石油气的清洁燃料,应纯烧、而非掺混的重要性,并提出了建立二甲醚标准化体系、完善二甲醚检测方法及扩大二甲醚应用领域等建议。     

二甲醚在工业和民用领域中的应用

二甲醚作为清洁燃料和新能源在替代液化石油气和柴油等方面有良好的应用前景。如何应用二甲醚、如何开发二甲醚下游产业是摆在人们面前很现实的问题。实践证明在液化石油气中掺混二甲醚的道路走不通,二甲醚纯烧是一条健康发展之路,二甲醚应在工业和民用工业用领域找到自己的位置。     

LPG掺混DME燃烧特性研究

为研究液化石油气掺混二甲醚的混合燃料的燃烧特性,依据GB16410—2007《家用燃气灶具》,对二甲醚质量分数分别为15%、20%和25%的混合燃料进行燃烧特性测试,通过实验室测试及理论计算得出:在一定的二甲醚掺混比例下,混合燃料的燃烧特性与液化石油气基本相同,并对混合燃料的应用提出了相关建议。     

探究液化石油气中二甲醚的检测与控制

在当前国际油价一路飙升下,液化石油气价格也随之水涨船高,为了能够进一步控制液化石油气的能耗与污染,目前其开始尝试将一定量从煤炭转化而来的清洁型燃料即二甲醚代替液化石油气,但也有部分企业选择将二甲醚掺入在液化石油气中用以充当高质量的液化石油气。为确保液化石油气具有较高的质量水平,则需要对其中二甲醚的含量进行精准检测和有效控制。基于此,本文将通过结合笔者自身工作实践,对液化石油气中二甲醚的检测与控制进行简要的分析研究。     

液化石油气、二甲醚产品标准述评

介绍了我国现行有效的液化石油气、二甲醚产品的国家标准、行业标准的关键内容。现行有效的液化石油气、二甲醚产品的国家标准、行业标准以及部分省市DME与LPG复合燃料的地方标准推动了燃气产业发展,为DME与LPG复合燃料国家标准的发布实施奠定了坚实基础。     

二甲醚的生产现状及发展前景

二甲醚是我国值得重点发展的清洁燃料,文章分析了二甲醚代替柴油作为汽车燃料、代替民用液化石油气的可行性,并对二甲醚的生产工艺如两步法、一步法、二氧化碳及生物质直接合成二甲醚等进行评述,认为一步法工艺比较适合我国国情,适用于化肥厂和甲醇厂生产二甲醚。     

液化石油气二甲醚混合燃料用橡胶密封圈安全性能的试验研究

以氟橡胶和普通丁腈橡胶两种橡胶密封圈为样本,分别参照GB 7512-2006《液化石油气瓶阀》与某企业的《二甲醚类橡胶密封材料》规定,在不同配比下的液化石油气二甲醚混合燃料环境中进行橡胶密封圈耐腐蚀性、耐老化和耐低温试验.试验数据显示两种样本的体积变化率与质量变化率都随二甲醚配比的变化而变化,但普通丁腈橡胶的质量变化率随混合燃料配比的变化更明显;耐老化及耐低温试验均合格.相同配比的试剂下,氟橡胶的耐腐蚀性能优于普通丁腈橡胶,因此,氟橡胶安全性能试验符合标准规定,可适用于储存液化石油气二甲醚混合燃料的钢瓶瓶阀的密封材料.     

规范在液化石油气中混装二甲醚复合燃料市场的建议

结合我国石油、天然气、煤炭资源形势及国内供需矛盾的日显突出,介绍了发展液化石油添加二甲醚新型复合燃料的必要性和良好的发展机遇,以及市场运行中存在的不规范行为,并对规范发展液化石油气、二甲醚复合燃料提出合理化建议。     

质子交换膜燃料电池系统低温启动技术研究进展

质子交换膜燃料电池电动汽车具有绿色环保、续航里程长等优点,但在温度较低的环境下存在启动困难甚至失败的问题,这一问题严重制约了质子交换膜燃料电池电动汽车的发展。研究调查了质子交换膜内部结冰的原理,简述了0℃以下低温环境下启动过程对质子交换膜本身、催化层、气体扩散层以及膜电极整体带来不同程度的损伤,重点分析了质子交换膜燃料电池电动汽车低温启动的策略,可大致分为三类：停机吹扫的控制策略、外部辅助加热和无辅助加热。分析表明每种方法都有其各自的优点与缺点,但总的来说单一的启动方法对质子交换膜燃料电池电动汽车低温启动的效果不如多种方法混合使用的效果理想,未来燃料电池电动汽车的低温启动技术将会朝着多种方法共同协助的趋势发展。     

甲醇燃料的研究进展与展望

随着化石资源的不断枯竭,能源消费将逐步向可再生能源时期发展.甲醇燃料不仅可以替代汽柴油作为内燃机燃料,而且也可以作为燃料电池等燃料或新型C1化工原料;不仅可以由化石能源生产,而且也可以由可再生能源生产:不仅具有高效、清洁燃料的特征,而且具有生产技术成熟、原料来源丰富的特点,能够实现可持续发展.甲醇燃料是理想的能源载体,在化石能源和可再生能源时期均可发展应用,特别是对于以煤为主要能源的中国,在由化石能源向可再生能源时期过渡的阶段,选择甲醇燃料为发展方向,意义将十分重大.     

Biodiesel from safflower oil and its application in a diesel engine

Safflower seed oil was chemically treated by the transesterification reaction in methyl alcohol environment with sodium hydroxide (NaOH) to produce biodiesel. The produced biodiesel was blended with diesel fuel by 5% (B5), 20% (B20) and 50% (B50) volumetrically. Some of important physical and chemical fuel properties of blend fuels, pure biodiesel and diesel fuel were determined. Performance and emission tests were carried out on a single cylinder diesel engine to compare biodiesel blends with petroleum diesel fuel. Average performance reductions were found as 2.2%, 6.3% and 11.2% for B5, B20 and B50 fuels, respectively, in comparison to diesel fuel. These reductions are low and can be compensated by a slight increase in brake specific fuel consumption (Bsfc). For blends, Bsfcs were increased by 2.8%, 3.9% and 7.8% as average for B5, B20 and B50, respectively. Considerable reductions were recorded in PM and smoke emissions with the use of biodiesel. CO emissions also decreased for biodiesel blends while NO_x and HC emissions increased. But the increases in HC emissions can be neglected as they have very low amounts for all test fuels. It can be concluded that the use of safflower oil biodiesel has beneficial effects both in terms of emission reductions and alternative petroleum diesel fuel.     

European Vehicle Emission Legislation—Present and Future

The Commission's Auto-Oil programme provided a framework for the development of future emission standards for motor vehicles based on sound science, technology capability, environmental need and cost effectiveness. Proposals developed from the results of the Auto-Oil programme paved the way for the agreement within the European Union of new emission standards for passenger cars, light commercial vehicles and heavy duty vehicles. These will be applied from 2000, 2005 and 2005, together with complimentary measures on fuel quality to take effect from 2000 and 2005. While decisions reached in the Council of Ministers and the European Parliament have, to some extent, circumvented the Auto-Oil II programme, the programme has continued the co-operative approach to future legislation by developing a coherent strategy to permit the achievement of necessary air quality targets at the lowest cost for society.     

Oxygenated blend design and its effects on reducing diesel particulate emissions

In order to meet Euro IV emission standards, diesel vehicles are compelled to install exhaust aftertreatment devices, which largely increases the overall cost. This paper explores the possibility to significantly reduce the particulate matter (PM) emissions by new fuel design. Several oxygenated blends were obtained by mixing the biodiesel, ethanol, dimethyl carbonate (DMC), and diesel fuels. The tests were conducted on two heavy-duty diesel engines, both with a high-pressure injection system and a turbocharger. The total PM and its dry soot (DS) and soluble organic fraction (SOF) constituents were analyzed corresponding to their specific fuel physiochemical properties. A blended fuel that contains biodiesel, DMC, and high cetane number diesel fuels was chosen eventually to enable the diesel engines to meet the Euro IV emission regulation. Based on the test results, the basic design principles were derived for the oxygenated blends that not only need the high oxygen content, but also the high cetane number and the low sulfur and low aromatic contents.     

The Future of Vehicle Propulsion – Combustion Engines and Alternatives

Increasing shortage on energy resources as well as future emission legislation development increase the pressure to develop more efficient, environmentally friendly propulsion systems for vehicles. This requires a further development of current diesel and gasoline engines as well as a careful look to alternatives like fuel cell systems or hybrid propulsion systems. This paper gives a survey about the current status and future developments of internal combustion engines (ICE), as well as some alternatives. A special focus will be on the impact on catalyst development which is in the topic of this conference. The ICE will dominate for vehicle propulsion in the next decades, but will undergo further development. In particular the shift to diesel engines and lean, turbocharged SI-engines will require a continuous development of aftertreatment systems, primarily for Particulates and NO _x . From the alternative fuels natural gas will be the first to play a significant role. The fuel cell will probably have the chance to enter the market only as an auxiliary power unit.     

我国发展醇醚汽车清洁燃料的可行性和优越性

从保证我国能源安全和环境双重角度出发,认为由我国资源相对丰富的煤炭转化为汽车清洁代用燃料是符合我国国情的重要途径。介绍了由煤转化为汽车燃料技术上可行的主要路线煤的直接液化,煤的间接液化和煤基合成含氧醇、醚燃料等;对甲醇、二甲醚清洁燃料用于汽车进行了可行性和优越性分析;在我国醇醚汽车燃料发展已有的基础上,讨论了推广应用中注意的问题及解决途径。     

Cooling Modules for Vehicles with a Fuel Cell Drive

In spite of the high efficiency of fuel cell drives for vehicles, cooling is a key problem. The present article reveals the reasons for cooling limits and their physical causes. This leads to deductions about what kind of actions can be taken to increase cooling performance. The implementation of these measures is demonstrated by means of examples of cooling modules for vehicles with a fuel cell drive.     

Effects of ethyl tert-butyl ether addition to diesel fuel on characteristics of combustion and exhaust emissions of diesel engines

The effects of ethyl tert-butyl ether (ETBE) addition to diesel fuel on the characteristics of combustion and exhaust emissions of a common rail direct injection diesel engine with high rates of cooled exhaust gas recirculation (EGR) were investigated. Test fuels were prepared by blending 0, 10, 20, 30 and 40 vol% ETBE to a commercial diesel fuel. Increasing ETBE fraction in the fuel helps to suppress the smoke emission increasing with EGR, but a too high fraction of ETBE leads to misfiring at higher EGR rates. While the combustion noise and NO_x emissions increase with increases in ETBE fraction at relatively low EGR rates, they can be suppressed to low levels by increasing EGR. Though there are no significant increases in THC and CO emissions due to ETBE addition to diesel fuel in a wide range of EGR rates, the ETBE blended fuel results in higher aldehyde emissions than the pure diesel fuel at relatively low EGR rates. With the 30% ETBE blended fuel, the operating load range of smokeless, ultra-low NO_x (<0.5 g/kWi h), and efficient diesel combustion with high rates of cooled EGR is extended to higher loads than with the pure diesel fuel.     

Various strategies for reducing Nox emissions of biodiesel fuel used in conventional diesel engines: A review

Energy demand, decreasing fossil fuel reserves, and health-related issues about pollutants have led researchers to search for renewable alternative fuels to either partially or fully replace fossil fuels. Among many alternative fuels, biodiesel became one of the most popular choices due to similar properties to that of conventional diesel. Biodiesel produces slightly lower brake thermal efficiency compared to that of conventional biodiesel, but has an advantage of reduced emissions of CO₂, CO, HC, and smoke. However, biodiesel shows higher NOx emission which, when used in increased biodiesel market, may become a serious problem. Various strategies were attempted by different researcher to reduce NOx emissions. In this paper, various strategies, adapted for reducing NOx emissions of biodiesel fuel used in diesel engines for automobile applications, are reviewed and discussed. The strategies are grouped into three major groups, namely combustion treatments, exhaust after-treatments, and fuel treatments. Among various strategies discussed, fuel treatments, such as low temperature combustion, mixing fuel additives and reformulating fuel composition, reduce NOx emission without compromising other emission and performance characteristics and they seem to be promising for future biodiesel fuel.