地球变暖是好还是坏？

气候转暖,冬季不那么严寒漫长,人们过冬当然会感到舒服多了。不过,全球变暖对人类的生产和生活产生了巨大影响,发展下去甚至会威胁到人类的生存。 气候变暖,水汽的蒸发会加快,这样一来改变了气流循环,使气候变化加剧,     

我国航空生物燃料的开发情况

在全球航空业的CO_2排放量呈逐年增加态势的今天,航空生物燃料因CO_2排放量比传统的以石油为原料的航空燃料少50%而倍受关注。美国、欧洲等国家及地区正在加快航空生物燃料的使用进程,并走在了世界前列,我国也正在进行航空生物燃料的开发及应用。介绍了我国航空燃料的生产及消费情况,全球航空业的CO_2排放情况,同时介绍了我国航空生物燃料的开发情况,最后提出了几点建议。     

我国航空生物燃料的开发情况

在全球航空业的CO_2排放量呈逐年增加态势的今天,航空生物燃料因CO_2排放量比传统的以石油为原料的航空燃料少50%而倍受关注。美国、欧洲等国家及地区正在加快航空生物燃料的使用进程,并走在了世界前列,我国也正在进行航空生物燃料的开发及应用。介绍了我国航空燃料的生产及消费情况,全球航空业的CO_2排放情况,同时介绍了我国航空生物燃料的开发情况,最后提出了几点建议。     

联合国权威报告称“生物燃料危害可能更大”

随着石油价格的不断上涨和全球变暖危害的日益显现，生物燃料对各国的吸引力越来越强。但联合国8同公布的一份报告却给生物燃料的前景泼了一盐凉水。报告警告说，尽管生物燃料的使用也许可以缓解全球气候变暖，为贫穷国家提供就业机会，但它对环境的危害及可能引发的一些社会问题，会将这些积极作用全部抵销掉!     

生物燃料发展动态

我国自2001年开始规模生产生物燃料以来,近几年发展速度很快。据有关部门公布,2006年我国生产燃料乙醇132万吨,替代车用汽油123万吨,含10％生物乙醇和90％汽油的混合燃料已在5省份全部及4省份的27个市试点使用,乙醇汽油调和能力达到1020万吨。表1是我国近几年来一些生物柴油中试规模生产厂家和使用原料的情况。     

漫谈生物燃料和生物柴油

探讨了国内对石油需求量日益增长的情况下推广和普及新型能源的重要性。对新能源在替代和缓解我国石油不足方面的重要意义进行了概述。指出寻找新型可替代能源成为中国未来能源战略的关键。     

泰国今年底禁用MTBE 鼓励使用生物燃料

泰国将在2006年底禁止销售燃料添加剂甲基叔丁基醚（MTBE）的计划，努力减轻对石油的过分依赖，实施更清洁的燃料政策，更多的使用燃料乙醇和生物柴油等生物燃料。泰国的乙醇产业正在快速发展，数家公司已投产新装置，或计划扩大现有装置的生产能力，并用木薯取代价格较高的甘蔗生产乙醇。在泰国政府的大力鼓励和支持下，越来越多的企业加入生产乙醇的行业，以满足人们对乙醇的大量需求。     

日本藻类生物燃料的研究进展

以藻类为原料的生物燃料不仅可作为石油燃料的替代燃料使用,而且可应对地球温暖化问题、粮食问题及能源安全等问题,因此,藻类生物燃料倍受关注。介绍了藻类生物燃料研究的概况、日本藻类生物燃料的研究情况。     

新型代用能源-生物燃料

随着石油能源危机的日益加剧,人们开始越来越多的将注意力投入到石油代用能源的研究中,其中一个重要项目就是生物燃料的研究和开发。本文着重介绍了燃料酒精和生物柴油这两种代用能源的优良性能、生产途径和应用现状,并简要分析了生物燃料的发展前景。     

Technical and Economic Analysis of Conventional and Supercritical Transesterification for Biofuel Production

The transesterification process with potassium hydroxide (KOH) catalyst and the methanol supercritical process were evaluated by Aspen HYSYS software. Castor oil and methanol were used as feed and alcohol. In order to accomplish verification, the simulation results were compared to a laboratory research. For economic analysis, these results were transferred to Aspen Economic Analyzer software. Piping and process equipment cost were calculated for the two processes. Additionally, direct and indirect costs of these processes were estimated.     

Dissolution rates of alkaline rocks by carbonic acid: Influence of solid/liquid ratio,temperature, and CO2 pressure

Dissolution rates of alkaline rocks, including wollastonite (CaSiO₃), olivine (Mg₂SiO₄), and phlogopite (KMg₃AlSi₃O₁₀(OH)₂), with high pressure aqueous CO₂ solution were measured to examine the feasibility of CO₂ fixation via carbonation. Influence of solid/liquid ratio (1.0–10 g/250 mL), temperature (303–353 K), and CO₂ pressure (1.0–3.0 MPa) on the extraction rates of calcium or magnesium ions was investigated. Under the experimental conditions studied, the calcium ion extraction rate from wollastonite was the highest among the three rock samples studied. The calcium concentration reached about 120 mg/L, and about 12% of the calcium in wollastonite sample was extracted after 60 min at 353 K with 1.0 MPa CO₂. The calcium and magnesium extraction ratios from the alkaline rocks were much lower than those from waste concrete powder. Increasing the extraction time and temperature would be an effective way to promote calcium extraction from wollastonite.     

Hydrotreating Model Comparison of Raw Castor Oil and its Methyl Esters for Biofuel Production

Some of the main problems during vegetable oil hydrotreating are the high heat of reaction released, the huge quantity of expensive hydrogen required, and the high corrosion rates in the equipment. Some insights into the advantages and disadvantages of processing raw vegetable oils or their respective fatty acid methyl esters are given. The ASPEN Plus process simulator was used for the simulation of a hydrotreating process, with two different feedstocks coming from the same plant: raw castor oil and castor oil methyl esters. That process was modeled with two stoichiometric reactors in series. The technical viability of using methyl esters as hydrotreating feedstock for the production of biofuels such as green gasoline and diesel is demonstrated.     

Global warming and the mining of oceanic methane hydrate

The impacts of global warming on the environment, economy and society are presently receiving much attention by the international community. However, the extent to which anthropogenic factors are the main cause of global warming is still being debated. There are obviously large stakes associated with the validity of any theory since that will indicate what actions need to be taken to protect the human races only home—Earth. Most studies of global warming have investigated the rates and quantities of carbon dioxide emitted into the atmosphere since the beginning of the industrial revolution. In this paper, we focus on the earths carbon budget and the associated energy transfer between various components of the climate system. This research invokes some new concepts: (i) certain biochemical processes which strongly interact with geophysical processes in climate system; (ii) a hypothesis that internal processes in the oceans rather than in the atmosphere are at the center of global warming; (iii) chemical energy stored in biochemical processes can significantly affect ocean dynamics and therefore the climate system. Based on those concepts, we propose a new hypothesis for global warming. We also propose a revolutionary strategy to deal with global climate change and provide domestic energy security at the same time. Recent ocean exploration indicates that huge deposits of oceanic methane hydrate deposits exist on the seafloor on continental margins. Methane hydrate transforms into water and methane gas when it dissociates. So, this potentially could provide the United States with energy security if the technology for mining in the 200-mile EEZ is developed and is economically viable. Furthermore, methane hydrate is a relatively environmentally benign, clean fuel. Such technology would help industry reduce carbon dioxide emissions to the atmosphere, and thus reduce global warming by harnessing the energy from the deep sea.     

Theoretical Analysis of Reaction and Diffusion Processes in a Biofuel Cell Electrode

A mathematical model for reaction diffusion processes in a biofuel cell electrode is discussed. This model is based on reaction diffusion equations containing a non‐linear term related to the rate of the enzyme reaction. Theoretical treatment of a reaction and diffusion processes in a biofuel cell electrode, for the steady and non‐steady state condition is discussed. Approximate analytical expressions for the steady and non‐steady state current density at the electrode surface are calculated by using the new approach to homotopy perturbation method and complex inversion formula. An analytical expression for the steady state current density is compared with numerical results and found to be excellent in agreement. A novel graphical procedure for estimating the Michaelis‐Menten constants and turnover rate solely from the current‐potential curve is suggested. Influence of the controllable parameters such as diffusion of the mediator, Michaelis‐Menten constant for substrate, second‐order rate constant, thickness of the film, turnover rate and initial substrate concentration on the current density are discussed.     

Separation of a Biofuel: Recovery of Biobutanol by Salting‐Out and Distillation

The second generation biofuel butanol can be produced by acetone‐butanol‐ethanol (ABE) fermentation, but the separation from the broth is still challenging. Therefore, dipotassium hydrogen phosphate was investigated as salting‐out agent. The ABE fermentation broth was enriched by a prefractionator after being preheated. The enriched ABE solution was salted out by K₂HPO₄ solutions at different temperatures. The water in the supplemented ABE solution was largely removed by the salting‐out method. The energy requirements for the prefractionator and the butanol column were significantly reduced. The total energy demand for the recovery of acetone, butanol, and ethanol by salting‐out and subsequent distillation was optimized. With the salting‐out process, the entire salting‐out and distillation method turned out to be more energy‐saving than the conventional one.     

二氧化碳回收技术及应用前景

二氧化碳作为化石燃料燃烧的副产物,直接排放会对大气造成污染,形成温室效应,而二氧化碳具有较高的工业和农用价值。常用的二氧化碳气体的分离、回收技术有化学溶剂吸收法、物理溶剂吸收法、吸附法、膜分离法、膜分离技术、催化燃烧法等。将二氧化碳转化成高附加值的化工产品有很大的市场潜力和发展前景,不仅可提高原料总利用率,降低生产成本,提高产品市场竞争力,而且可改善地球环境,具有良好的社会效益和经济效益。     

Ternary Blends of Renewable Fast Pyrolysis Bio-Oil,Advanced Bioethanol,and Marine Gasoil as Potential Marine Biofuel

An alternative for reducing emissions from marine fuel is to blend bio-oil from lignocellulose non-edible feedstocks to diesel fossil fuels. Phase diagrams of the ternary systems were built to represent the transition from heterogeneous regions to homogeneous regions. Four homogeneous blends of bio-oil of eucalyptus-bioethanol-marine gasoil were experimentally characterized with respect to the most important fuel parameters for marine engines: water content, flash point, low heating value, viscosity, and acidity. Blends with closer properties to marine gasoil replacement, lower costs, and environmental impacts should be tested for large engines.     

Hot Water Pretreatment of Lignocellulosic Biomass: An Effective and Environmentally Friendly Approach to Enhance Biofuel Production

Hot water pretreatment without usage of chemicals is a particularly attractive approach for pretreatment of lignocellulosic biomass due to its fewer safety and environmental concerns as well as relatively low cost. However, a prohibitive amount of sugar degradation products limits the efficiency of such pretreatment, and excessive water consumption accompanied with the over‐diluted sugar streams still impedes the implementation of this pretreatment to be an economically viable pathway. These limitations are associated with the scant attention of water‐biomass interaction mechanism and engineering aspects regarding kinetic modeling and reactor configurations. This review aims at investigating those critical factors in terms of chemistry and engineering fundamentals in order to understand the correct axiomatic approaches needed to advance this technology. Various reactor configurations and kinetic models are evaluated to explore optimization strategies toward application.     

Treatments of low rank coals for improved power generation and reduction in Greenhouse gas emissions

Reduction in ash constituents by water washing, and also at specific pH values, was systematically studied for three low-rank coals. Acid treatment removed inorganic constituents if accompanied by efficient water washing; at elevated temperatures this can also reduce moisture. The ash components are present in the coal matrix and also as numerous aluminosilicates particles containing K, Na, Mg, Fe and Ca; acid treatment reduced the ash constituents to mainly quartz and clay particles. The ash chemistry of treated and untreated coals was studied over the temperature range 800 °C to 1400 °C. The ash from treated coals consisted mostly of α-quartz, and when heated at 800 °C to 1500 °C, was transformed into mainly amorphous silica and cristobalite, and melted at 1300–1500 °C. Ash from untreated coals melted at or below 1100 °C. The impact of low rank coals with lower moisture, and also coals with lower ash and moisture, was assessed for power generation using the GateCycle™ package. The results show: (i) moisture reduction lowers CO₂/MWh by a small amount but often increases fouling, and (ii) reduction in ash and moisture would eliminate ash fouling and significantly reduce the CO₂/MWh compared with current power plant.