甲醇制取烃类燃料的实验研究

采用固定床反应器对不同温度和压力下甲醇制取烃类燃料进行了研究。催化剂选用沸石分子筛HZSM-5,Si/Al比为25;反应原料为甲醇水溶液(83%)。在体积空速为8h-1的条件下,研究了300、350、400、450℃及常压、1、1.5、2、2.5 MPa压力下甲醇的转化率、油相得率和气体得率。研究结果显示,反应的最佳温度为400℃、压力为2 MPa,在此条件下,甲醇转化率接近100%,油相得率最高。     

Effects of consumer subsidy on household fuel switching from coal to cleaner fuels: A case study for anthracites in Korea

The Korean coal industry is in a transition under low carbon policy through the steady reduction of coal production. Since consumer subsidy for the consumption of anthracites briquette in low-income households caused a distortion in domestic coal market, the so-called coupon program will be the first target in energy reform policy in order to induce fuel switching from anthracites to alternative clean energy. This paper tries to identify various factors that influence households' fuel switching decision. Disutility from briquette consumption is also considered as an important factor. Using the 2007 census data on briquette-consuming households, it is found that the coupon program provides an adverse effect to switching fuels to clean energy while the disutility of briquettes is positively associated with the probability of fuel switching. However, the empirical finding suggests that the policy alone attempting to remove coupon program may fail to switch fuels unless the cost of boiler changes is substantially reduced through the provision of accessible networks to alternative energy sources. It indicates that reform policy for consumer subsidy must be understood in line with more comprehensive regional energy plans to resolve energy poverty issue.     

A Life Cycle Assessment of lithium battery and hydrogen-FC powered electric bicycles: Searching for cleaner solutions to urban mobility

Smart mobility is day by day becoming one of the crucial issues to address in order to reduce environmental impacts such as global warming, acidification, photochemical smog, among others. The growing concerns about urban air quality are the driving force for cleaner and more efficient transport systems. Several new transport technologies are being developed, in particular concerning electric vehicles, considered a suitable solution to urban air pollution problems. However, these vehicles require electric and electronic devices that might give rise to a new set of environmental problems in their production, operation and disposal phases. Are electric vehicles a really cleaner solution? This paper aims at answering this question, by comparing two kinds of vehicle, a lithium battery powered electric bike and a hydrogen-fuel cell operated one, using internal combustion engine vehicles as benchmark. The fuel cell bike uses a proton exchange membrane fuel cell (PEMFC) to convert hydrogen into electricity. In this study, Life Cycle Assessment is applied to evaluate the environmental burdens of the production of these two vehicles and compare their environmental performances per 100 km travelled. The study, not only includes vehicle road operation but also embraces production and distribution of bikes, electric battery, PEMFC and energy carriers (electricity and hydrogen) over the vehicle's entire lifetime. The LCA evaluation of the vehicle production phases shows that the construction of the H-bike results more impacting than the E-bike in all the considered categories due to the presence of more complex components technology. Instead, when the boundary is shifted to the operational phases of the vehicles including the energy carriers production, the situation is reversed and the environmental performance of the H-bike results better than the one of E-bike.     

Resource analysis of the Chinese society 1980–2002 based on exergy—Part 1: Fossil fuels and energy minerals

The resource inflow to the Chinese society from 1980 to 2002 is investigated based on exergy as a unified quantifier of natural resources. The major resources entering the society are divided into 17 sectors, with the annual policy for the individual group is analyzed corresponding to the exergy resource inflow. This study is divided into five consequential parts. This paper as the first part introduces the fossil fuels and energy materials entering the society, including coal, crude oil, natural gas, iron ores, nonferrous metal ores and nuclear power. The coal production, which comes form unified central planning, collective and individual parts, is analyzed according to the administrative institutions associated with variable policies. The consumption of coal is also described concerning thermal power generation, coking, heating, private consumption and gasification. The storage capacity, investment and import in crude oil production, which is imperative for the rapid economic development, are depicted. The natural gas production, slowly expanding during the study period, is illustrated according to the discovered and operating gas fields. Production of iron ores and nonferrous metal ores and nuclear power produced from uranium ores are represented in this paper.     

Large scale disposal of waste sulfur: From sulfide fuels to sulfate sequestration

Petroleum industries produce more byproduct sulfur than the market can absorb. As a consequence, most sulfur mines around the world have closed down, large stocks of yellow sulfur have piled up near remote operations, and growing amounts of toxic H₂S are disposed of in the subsurface. Unless sulfur demand drastically increases or thorough disposal practices are developed, byproduct sulfur will persist as a chemical waste problem on the scale of 10⁷ tons per year.     

Energy access and transition to cleaner cooking fuels and technologies in Sri Lanka: Issues and policy limitations

Easy energy access is a trigger for human, social, and economic development. A research project was undertaken in Sri Lanka to broaden the understanding of human dimension of energy access and technologies. A questionnaire survey, covering 2269 households, gathered data on socio-economic contexts and issues influencing a transition towards clean cooking facilities. The findings reveal that the transition is impeded by four factors: the lack of motivation and the pressure for switching over to cleaner facilities, the lack of modern energy technology options, the financial risks, and the lack of financing and other support. The paper describes the delicate two-way interrelation between women earning wages and the transitions to cleaner cooking fuels and technologies. The findings suggest the need for a policy framework involving the stakeholders, financing and standardised technologies. To make a change it is proposed to introduce a national, integrated policy incorporating financing and energy governance.     

The impacts of compression ratio on the performance and emissions of ice powered by oxygenated fuels: A review

Energy sources are becoming a governmental issue, with cost and stable supply as the main concern. Oxygenated fuels production is cheap, simple and eco-friendly, as a well as can be produced locally, cutting down on transportation fuel costs. Oxygenated fuels are used directly in an engine as a pure fuel, or they can be blended with fossil fuel. The most common fuels that are conceded under oxygenated fuels are ethanol, methanol, butanol Dimethyl Ether (DME), Ethyl tert-butyl ether (ETBE), Methyl tert-butyl ether (MTBE) and biodiesel that have attracted the attention of researchers. Due to the higher heat of vaporization, high octane rating, high flammability temperature, and single boiling point, the oxygenated fuels have a positive impact on the engine performance, combustion, and emissions by allowing the increase of the compression ratio. Oxygenated fuels also have a considerable oxygen content that causes clean combustion. The aim of this paper was to systematically review the impact of compression ratio (CR) on the performance, combustion and emissions of internal combustion engines (ICE) that are operated with oxygenated fuels that could potentially replace petroleum-based fuels or to improve the fuel properties. The higher octane rating of oxygenated fuels can endure higher compression ratios before an engine starts knocking, thus giving an engine the ability to deliver more power efficiently and economically. One of the more significant findings to emerge from this review study was the slight increases or decreases in power when oxygenated fuel was used at the original CR in ICE engines. Also, CO, HC, and NOx emissions decreased while the fuel consumption (FC) increased. However, at higher CR, the engine performance increased and fuel consumption decreased for both SI and CI engines. It was seen the NOx, CO and CO₂ emissions of oxygenated fuels decreased with the increasing CR in the SI engine, but the HC increased. Meanwhile, in CI engine, the HC, CO and NOx decreased as the CR increased with biodiesel fuel.     

Global oil outlook: return to the absence of surplus and its implications

As we approach the end of the 20th century, the global oil picture starts to look more like the early 1970s, which set the scene for the first oil crisis in 1973. The “security margin” — the gap between demand and production capacity, has been shrinking since the early 1990s. In 1985 OPEC was producing at only 55% of capacity. By 1997 capacity utilization had risen to 95% and, barring the full re-entry of Iraq into the oil market, capacity utilization in 1998 is projected to rise to 96% with a growth of more than 1.6 million barrels a day (mbd) in global demand. No wonder, then, that the “capacity question” has been termed “oil's perennial problem”. The dilemma confronting producers is either they face the danger of over investing if demand grows slowly or not at all, or they run the risk of investing too little, too late. Yet, without outright investment, the capacity constraint may start to bite at some point in the near future. This paper will endeavour to analyse the origins of the shrinking “security margin” and its impact on the global oil supplies, the price of oil and the global economy. It will argue that under such conditions, one has to seriously consider the possiblity of a third oil crisis capable of again disrupting the global economy, triggered again by political upheaval in the Middle East.     

Influence of intake manifold design on in-cylinder flow and engine performances in a bus diesel engine converted to LPG gas fuelled, using CFD analyses and experimental investigations

Diesel engines, especially for trucks and buses, cause many economical and ecological problems. Diesel exhaust emissions are a major source of pollution in most urban centers around the world. Furthermore, the price of crude oil continues to increase rapidly. The use of alternative fuels (liquified petroleum gas, LPG and compressed natural gas, CNG) and the optimization of combustion present effective solutions. Improving combustion is directly related to improving the intake aerodynamic movements which is influenced by the inlet system, especially the intake manifold. In this paper we have studied the geometry effects of two intake manifolds on the in-cylinder flows by two methods, numerically and experimentally. These two manifolds are mounted on a fully instrumented, six-cylinder, 13.8 l displacement, heavy duty, IVECO engine, installed at the authors’ laboratory, which is used to power the urban bus diesel engines in Sfax. This engine was modified to bi-fuel spark ignition engine gasoline and gas fuelling. The 1st manifold presents an unspecified geometry whereas the 2nd presents an optimal filling geometry.A three-dimensional numerical modeling of the turbulent in-cylinder flow through the two manifolds was undertaken. The model is based on solving Navier-Stokes and energy equations in conjunction with the standard k-ε turbulence model, using the 3D CFD code FloWorks. This modeling made it possible to provide a fine knowledge of in-flow structures, in order to examine the adequate manifold. Experimental measurements are also carried out to validate this manifold by measuring the important engine performances. Brake power (BP), brake torque (BT) and brake thermal efficiency (BTE), are increased by 16%, 13.9%, and 12.5%, respectively, using optimal manifold. The brake specific fuel consumption (BSFC) is reduced by 28%. Simulation and experiments results confirmed the benefits of the optimized manifold geometry on the in-cylinder flow and engine performances.     

A CGE analysis to study the impacts of energy investment on economic growth and carbon dioxide emission: A case of Shaanxi Province in western China

A two-region ten-sector computable general equilibrium (CGE) model was built to analyze the effects of investment growth in the energy sectors of western areas of China on the local economy and emission of carbon dioxide (CO₂). There are three different scenarios in the quantitative analysis for the investment increase in energy sectors of the western areas. The investment to energy sectors is increased at the rate of 20%, 40%, and 60%. Based on Shaanxi Province's 2002 input–output table, the change of some macro-economic variables is simulated under these scenarios. The results show that the GDP growth is at 0–8.92%, households disposable income growth is at 0–8.94%, and emission of carbon dioxide growth is at 0–11.10% when the investment growth is at 0–60%. The oil and gas sector is the most effective sector with a growth rate of 0–19.47%.     

Bio-oil catalytic reforming without steam addition: Application to hydrogen production and studies on its mechanism

A novel process for hydrogen production via bio-oil catalytic reforming without steam addition was proposed. The liquid feedstock was a distillation fraction from crude bio-oil molecular distillation. The fraction obtained was enriched with the low-molecular-weight organics (acids, aldehydes, and ketones), and contained nearly all of the water from crude bio-oil. The highest catalytic performance, with a carbon conversion of 95% and a H₂ yield of 135 mg g⁻¹ organics, was obtained by processing the distillate over Ni/Al₂O₃ catalyst at 700 °C. The steam involved in the reforming reaction was derived entirely from the water in the crude bio-oil. The fresh and spent catalysts were characterized by N₂-physisorption, thermogravimetric analysis, and high-resolution transmission electron microscopy. To further understand the reaction mechanisms, symmetric density functional theory calculations for decomposition were performed on four model compounds in bio-oil (acetic acid, hydroxyacetone, furfural, and phenol) over the Ni(111) surface. In addition, the decomposition of H₂O∗ to OH∗ and O∗ and their subsequent steam reforming reactions with carbon precursors (CH∗ and CH₃C∗) were also examined.     

Equilibrium modeling of gasification: Gibbs free energy minimization approach and its application to spouted bed and spout-fluid bed gasifiers

Spouted beds have been found in many applications, one of which is gasification. In this paper, the gasification processes of conventional and modified spouted bed gasifiers were considered. The conventional spouted bed is a central jet spouted bed, while the modified spouted beds are circular split spouted bed and spout-fluid bed. The Gibbs free energy minimization method was used to predict the composition of the producer gas. The major six components, CO, CO₂, CH₄, H₂O, H₂ and N₂, were determined in the mixture of the producer gas. The results showed that the carbon conversion in the gasification process plays an important role in the model. A modified model was developed by considering the carbon conversion in the constraint equations and in the energy balance calculation. The results from the modified model showed improvements. The higher heating values (HHV) were also calculated and compared with the ones from experiments. The agreements of the calculated and experimental values of HHV, especially in the case of the circular split spouted bed and the spout-fluid bed were observed.     

Green biorefinery (GBR) scenarios for a two-cut silage system: Investigating the impacts of sward botanical composition, N fertilisation rate and biomass availability on GBR profitability and price offered to farmers

In Ireland, grass is a readily available bioresource. It has previously been established that Green biorefinery (GBR) could become a potential use of Irish grasslands, and a blueprint for a sustainable GBR industry in Ireland has been developed. The objective of this paper is to use scenario analysis to investigate the sensitivity of the profitability of the GBR blueprint to variations in grass quantity and quality as a function of botanical composition, fertiliser application, and biomass availability. As an outcome of these scenario analyses, the price the GBR can offer to farmers above their production costs (€ t⁻¹ dry matter) was calculated. Results of the scenario analyses determined that GBR systems located in a catchment area of permanent pasture (Lolium perenne > 60%) with annual grass yields in the range of 9-12 t dry matter (DM) ha⁻¹, and supplied with grass biomass with a fibre content of 500-555 g kg⁻¹ DM and a protein content of 110-130 g kg⁻¹ DM, were viable. The most profitable scenarios were generated when nitrogen fertiliser application was greater than 90 kg ha⁻¹ a⁻¹. Biomass availability of less than 30% resulted in reduced profitability and for some scenarios resulted in a loss for both the GBR and farmer due to increased transport costs. Within the scenario assumptions of this study, grass feedstock was valued at €4-€56 t⁻¹ dry matter above production costs. However, this value depended on the yields and biomass availability of the GBR catchment area.     

Studies of energetic compounds, part 29: effect of NTO and its salts on the combustion and condensed phase thermolysis of composite solid propellants, HTPB-AP

The effect of 5-nitro-2,4-dihydro-3H-1,2,4-triazole-3-one (NTO) and two of its transition metal salts, namely Cu(NTO)₂ and Fe(NTO)₃, during the combustion of composite solid propellants (CSPs) of hydroxyl-terminated polybutadiene (HTPB) and ammonium perchlorate (AP) has been studied. The activities of Cu(NTO)₂ and Fe(NTO)₃ have been compared with those of CuO and Fe₂O₃ at their equivalent metal concentrations. The processing parameters and mechanical properties of the propellants were also evaluated using Cu(NTO)₂ and Fe(NTO)₃ as additives, and a comparison has been made with that of copper chromite (CC) and active iron oxide (AIO) at pilot plant scale. The safety aspects of using these energetic salts as burning-rate modifiers have been studied in terms of the impact-sensitivity of the modified propellants. An attempt has been made to evaluate experimentally the condensed phase activity of these additives during the slow thermolysis of propellants, as well as AP. Rapid thermolysis of the propellants and AP has been studied using measurements of ignition delay.     

Direct water balance analysis on a polymer electrolyte fuel cell (PEFC): Effects of hydrophobic treatment and micro-porous layer addition to the gas diffusion layer of a PEFC on its performance during a simulated start-up operation

Effects of hydrophobic treatment and micro-porous layer (MPL) addition to a gas diffusion layer (GDL) in a polymer electrolyte fuel cell (PEFC) have been investigated from water balance analysis at the electrode (catalyst layer), GDL and flow channel in the cathode after a simulated start-up operation. The water balance is directly analyzed by measuring the weight of the adherent water wiped away from each the component. As a result, we find that hydrophobic treatment without MPL leads to the increase in liquid water accumulation at the electrode which limits the oxygen transport to the catalyst and then lowers the cell voltage rapidly during start-up, whereas the treatment decreases the water at the GDL. The water accumulation at the electrode also decreases the cumulative current that represents the power generation and calorific power indispensable for warming up at a temperature below freezing point. On the other hand, we directly find that the hydrophobic treatment with MPL addition suppresses the water accumulation at the electrode, which increases the cumulative current. In addition, it is found that increase in air permeability of a GDL substrate by its coarser structure increases the cumulative current, which is explained by enhancing the exhaust of the product water vapor and liquid as well as by enhancing the oxygen transport directly. Thus, the hydrophobic treatment with MPL addition and larger air permeability of a GDL substrate improve the start-up performance of a PEFC.     

Equation of state for fluid mixtures based on the principle of corresponding states with a two‐fluid model: Application to fluid mixtures of water + ammonia

We propose an equation of state for fluid mixtures of water + ammonia which is expressed in Helmholtz free energy as a function of temperature, molar volume, and mole fraction. IAPWS Formulation 1995 for water and the equation of state by Tillner‐Roth and colleagues for ammonia should be used for each pure component with the present equation. We applied the principle of corresponding states with a two‐fluid model to the present equation for fluid mixtures. On comparison with experimental data, the uncertainty in property calculations by the present equation was evaluated: within ±0.03 · x for bubble point curve, within ±0.04 · x for dew point curve, within ±0.02 · ρ^L for saturated liquid density, and within ±0.02 · ρ for PVTX properties. © 2002 Wiley Periodicals, Inc. Heat Trans Asian Res, 131(4): 320–330, 2002; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.10023