Wood gas generators for small power (∼ 5 hp) requirements

This paper reports experimental and developmental studies on wood gas generators meant for running 5 hp diesel engines in irrigation water pumping. Critical inputs for the design of small reactors are presented. A prototype of the gas generator based on these inputs has been built and tested along with a diesel engine pumpset. The results of various tests on the system are described along with some critical operational features. The lowest amount of diesel at which the engine could be run with a mixture of diesel and gas is about 15% of the consumption with diesel alone. However, to obtain the same energy, that is the same amount of water at a given height, the best replacement of diesel obtained is about 75%. The paper also comments on the economics of such systems. The results presented here are the outcome of a project ‘Wood gas generators for engines of less than 10 hp’ financed and administered by Karnataka State Council for Science and Technology, Indian Institute of Science, Bangalore.     

Development of ceramic components for car gas turbines

Components for internal combustion engines are being develop ed from non-oxide and oxide ceramzc r:naterzals at the Research Division of Volkswagenwerk AG. The properties of some materials, the process technology and the design methods of the components are discussed. The advantages of the incorporation of ceramics into automotive gas turbines are deduced and th e present state of Volkswagen’s component development is reported.     

回热循环燃气轮机中回热器的动态特性研究

采用多段集中参数模型对具有分布参数特性的回热器建模，简化了由偏微分方程带来的大量计算，应用Matlab／Simlink软件作为仿真平台，采取数值方法求解，对具体回热燃气轮机中的回热器进行了仿真，结果表明，回热器时间常数较大，在回热循环燃气轮机仿真中回热器的热惯性不能忽略，而且是影响系统平衡稳定性的重要因素．     

Lifing issues in hot gas path components of heavy-duty gas turbines

Abstract

Gas turbine hot-gas-path components, which include combustion liners, transition pieces, turbine nozzles and turbine buckets, are exposed to hot gases discharged from combustion systems and suffer from severe materials degradation and damage even in the early stage of operation. The severity of the damage and degradation increases with increasing inlet temperature and size of the gas turbines, which also increase the maintenance cost. ‘Lifing’ of components is, therefore, becoming a very critical issue. This paper describes several kinds of component damage and material degradation occurring in the 1,100°C- and 1,300°C-class heavy-duty gas turbines and then shows how we revised those component lives from the original design ones. Analytical-based assessment methods associated with condition-based assessment ones, some examples of assessment results, and component life extension technologies are also described.     

Hydrogen sulfide removal from coal gas by the metal-ferrite sorbents made from the heavy metal wastewater sludge

The metal-ferrite (chromium-ferrite and zinc-ferrite) sorbents made from the heavy metal wastewater sludge have been developed for the hydrogen sulfide removal from coal gas. The high temperature absorption of hydrogen sulfide from coal gas with the metal-ferrite sorbent in a fixed bed reactor was conducted in this study. The metal-ferrite powders were the products of the ferrite process for the heavy metal wastewater treatment. The porosity analysis results show that the number of micropores of the sorbents after sulfidation and regeneration process decreases and the average pore size increases due to the acute endothermic and exothermic reactions during the sulfidation–regeneration process. The FeS, ZnS, and MnS peaks are observed on the sulfided sorbents, and the chromium extraction of the CFR6 can fulfill the emission standard of Taiwan EPA. The suitable sulfidation temperature range for chromium-ferrite sorbent is at 500–600 °C. In addition, effects of various concentrations of H₂ and CO were also conducted in the present work at different temperatures. By increasing the H₂ concentration, the sulfur sorption capacity of the sorbent decreases and an adverse result is observed in the case of increasing CO concentration. This can be explained via water-shift reaction.     

液化天然气冷能利用发电技术浅析

阐述了国内外LNG利用的形势,论述了LNG作为燃料的优势.通过分析LNG冷量利用原理及对LNG进行的分析,得出回收LNG冷量发电不仅有效利用能源,而且减少机械制冷造成的大量电能消耗,具有可观的经济效益和社会效益.对国内外利用LNG冷量发电方式进行总结分类,具体给出一些典型流程图和成功的应用范例.     

An overview of power generation in New Zealand

Abstract

Two distinct risks cast a shadow over the sustainability of the existing energy mix. One is security of supply. The diversification of energy sources – both geographical and technological – could mitigate those risks. The second is environmental. Climate change in particular has raised questions about the sustainability of the current fossil fuel emission-intensive mix.

The government is currently investigating whether current R&D priorities and programmes are adequately focused and resourced to bring on-stream the energy technologies of the future. The future energy scenarios explored in the National Energy Strategy will help deliver a view of where some of the potentials and roadblocks currently lie in respect of new energy technologies. This in turn will guide the development of a roadmap of energy research priorities.

Equally important is gaining a better understanding about the actual distribution of research effort on the energy-related technologies and market deployment of different technologies.

While science, research and innovation in a global and highly competitive marketplace coupled with consumer preferences will be a decisive influence, timely access to new technologies and energy resources is of significant national interest.     

Comparison of total energy systems using gas turbines and diesel engines for combined cooling

A gas turbine engine was used to drive the compressor of a vapour compression cycle so that the usually wasted energy in the exhaust gases was partially recovered and used in the generator of an absorption cycle. The cooling effect was therefore boosted. The degree of energy utilization was further enhanced when the energy released from the absorber and condenser of both cycles was recovered in the form of hot water, which could be used for different applications. The performance parameters for this combined system, such as the cooling effect, total heat recovered and performance effectiveness ratio, were calculated for various evaporator and condenser temperatures. It was found that a system driven by a gas turbine gives a better performance than a diesel engine system under similar operating conditions.     

天然气能量计量不确定度评定方法

在研究ISO 15112:2007、GB/T 22723—2008《天然气能量的测定》和其它相关标准的基础上,根据国内某长输管道天然气能量计量的实际情况,对天然气能量计量中的流量测量、温度测量、压力测量、压缩因子测量等参数不确定度进行了研究,提出了不确定度评定计算方法.并使用文中的方法对国内某长输管线上5个有代表性的实验站点的流量测量、温度测量等的不确定度进行了评定,验证了计算方法的正确性和合理性.     

我国致密砂岩气和页岩气的发展前景和战略意义

根据资源、技术和现状全面分析了我国致密气和页岩气发展的关键因素。从资源品质、类型和政策等出发,提出我国致密气和页岩气发展路线和三步走的发展前景。系统论述了我国致密气和页岩气发展对于改善能源结构和保障国家能源安全具有重要战略意义。     

燃煤电站烟气污染物深度脱除技术的分析

近年来雾霾天气的频繁出现使得细颗粒物(PM2.5)成为了公众关注的热点,PM2.5的控制也已增加到2012年发布的《环境空气质量标准》中,而目前我国现有的烟气污染物控制技术难以脱除PM2.5,因此,为深度脱除PM2.5、SO2、SO3以及重金属等烟气污染物,开发燃煤电站烟气污染物深度脱除技术(深度脱除技术)成为亟待解决的问题。本文系统分析了开发适用于我国燃煤电站的深度脱除技术的必要性以及存在的问题,重点分析研究了PM2.5脱除技术、全负荷下超超临界锅炉的低NOx排放以及SCR工作温度的适应性。最后,以某电厂2×660 MW超临界机组为例,介绍了烟气污染物深度脱除系统方案,以此为基础,分析提出了1 000 MW超超临界机组烟气污染物深度脱除的技术路线。     

End corrections for rarefied gas flows through capillaries of finite length

The influence of end effects on rarefied gas flows through moderately long capillaries is investigated by implementing the concept of effective capillary length, representing a sum of the real length of capillary and its increment. To calculate the length increment, a flow field near the inlet cross section of capillary is analyzed on the basis of the linearized kinetic equation. Far from the inlet inside of capillary, the solution is matched at the level of the distribution function with the one-dimensional solution corresponding to the flow in an infinite capillary. Far from the inlet outside of capillary, the gas is assumed to be in equilibrium at a specific pressure and temperature. The capillary length increment has been calculated as a function of the gas rarefaction. Using these results it is possible to estimate a flow rate through a moderately long capillary without hard calculations for the complete geometry.     

输气管道气体流经阀门气动噪声产生机理分析

为区分输气管道泄漏音波与阀门噪声,为输气管道音波法泄漏检测提供理论依据及数据库、控制阀门噪声提供解决办法,从音波产生机理角度采用CFD软件耦合专业声学软件方法对输气管道气体流经阀门产生的气动噪声进行研究,建立气动噪声模型,探究气动噪声产生机理及传播、衰减规律。在CFD（Computational Fluid Dynamics）软件中采用大涡湍流模型对气体流经阀门时的瞬态流场求解分析,获得流场分布如脉动压力、脉动速度数据;将CFD计算所得数据导入专业声学软件进行联合仿真,生成气动噪声源项,包括偶极子声源及四极子声源,建立气动噪声产生传播模型,求解输气管道气体流经阀门的气动噪声。     

Reduction of excess sludge production in sequencing batch reactor through incorporation of chlorine dioxide oxidation

In this study, chlorine dioxide (ClO₂) instead of chlorine (Cl₂) was proposed to minimize the formation of chlorine-based by-products and was incorporated into a sequencing batch reactor (SBR) for excess sludge reduction. The results showed that the sludge disintegrability of ClO₂ was excellent. The waste activated sludge at an initial concentration of 15 g MLSS/L was rapidly reduced by 36% using ClO₂ doses of 10 mg ClO₂/g dry sludge which was much lower than that obtained using Cl₂ based on similar sludge reduction efficiency. Maximum sludge disintegration was achieved at 10 mg ClO₂/g dry sludge for 40 min. ClO₂ oxidation can be successfully incorporated into a SBR for excess sludge reduction without significantly harming the bioreactor performance. The incorporation of ClO₂ oxidation resulted in a 58% reduction in excess sludge production, and the quality of the effluent was not significantly affected.     

Jaya Learning-Based Optimization for Optimal Sizing of Stand-Alone Photovoltaic,Wind Turbine,and Battery Systems

Renewable energy sources (RESs) are considered to be reliable and green electric power generation sources. Photovoltaics (PVs) and wind turbines (WTs) are used to provide electricity in remote areas. Optimal sizing of hybrid RESs is a vital challenge in a stand-alone environment. The meta-heuristic algorithms proposed in the past are dependent on algorithm-specific parameters for achieving an optimal solution. This paper proposes a hybrid algorithm of Jaya and a teaching–learning-based optimization (TLBO) named the JLBO algorithm for the optimal unit sizing of a PV–WT–battery hybrid system to satisfy the consumer’s load at minimal total annual cost (TAC). The reliability of the system is considered by a maximum allowable loss of power supply probability (LPSP_max) concept. The results obtained from the JLBO algorithm are compared with the original Jaya, TLBO, and genetic algorithms. The JLBO results show superior performance in terms of TAC, and the PV–WT–battery hybrid system is found to be the most economical scenario. This system provides a cost-effective solution for all proposed LPSP_max values as compared with PV–battery and WT–battery systems.     

天然气输送能量的利用

阐述利用天然气输送能量的必要性和效益,详细介绍气态天然气和液化天然气输送能量利用的方法和流程,最后提出跨行业利用天然气输送能量的设想。     

Approach for natural gas to be a primary energy source in China

This work reveals the positioning of natural gas in the evolution of world energy and the general law of its development. In the long-term adjustment of energy structure, natural gas has gradually become the primary energy source because of five factors: policy, resources, technology, facilities, and market. To expedite the revolution of energy production and consumption, China must urgently expand the use of natural gas toward a more positive role in complementing coal and renewable energy and prioritize its usage in three areas, namely, urban gas, power generation, and industrial fuel. Natural gas is expected to account for approximately 15% of China’s total energy consumption in the future. For natural gas to be the primary energy, the exploitation of gas resources must be expanded, resource access must be improved, a flexible trade system must be set up, infrastructure investment must be increased, and the security system must be enhanced.     

Mechanism for sludge acidification in aerobic treatment of coking wastewater

This work was undertaken to investigate the cause of sludge acidification that led to disruption of the activated sludge process treating coking wastewater from a steel-making plant in Taiwan. An activated sludge reactor (ASR) with a working volume of 80 L was used as a model system to simulate the behavior of the real wastewater treatment process. Parameters that may cause acidification or inactivation of the sludge (NH(3), SCN(-), S(2)O(3)(2-) and CN(-)) were studied individually to examine for their effects on the performance of the ASR. The results show that high loading of NH(3), SCN(-) and CN(-) did not lead to pH decrease, while the ASR attained 85% COD removal and nearly 100% SCN degradation. In contrast, when the wastewater was supplemented with ca. 1,000 mg/L of S(2)O(3)(2-), the pH dropped to nearly 4.0 in 2 days and the COD and SCN removal yields were significantly lower (at 50 and 0-20%, respectively). Thus, overloading of S(2)O(3)(2-) was apparently a key factor causing sludge acidification. The results suggest that to ensure a normal functioning of the activated sludge, the influent S(2)O(3)(2-) concentration should be closely monitored and that the pH control of the ASR is indispensable when the S(2)O(3)(2-) loading is in excess.     

CO_2/CH_4分离膜技术在沼气提纯中的应用研究进展

生物天然气(BNG)是近年来新兴的一种可再生清洁能源.制备生物天然气的核心是去除沼气中的二氧化碳.CO2/CH4分离膜技术被认为是未来沼气提纯领域最有潜力的一项技术.本文对CO2/CH4分离膜技术在沼气提纯中的应用研究和发展现状进行综述,包括CO2/CH4分离膜材料的最新发展;膜法沼气提纯工艺过程的设计;欧美膜法沼气提纯工业化装置的近况等;最后对膜法沼气提纯技术的主要困难及未来发展方向进行分析与讨论.