Efficiency of PGDC electric filters behind a rotary furnace for firing dolomite

Conclusions Tests on electric filters type PGDC for extracting highly ohmic dolomite dust showed that when the rotary furnace is burning natural gas, and the flue gas velocity is 1.2–1.3 m/sec, the apparatus operates reliably with an efficiency of at least 90.0%When sulfurous fuel oil grade-100 (containing 3.2–3.5% sulfur) is being burned, the efficiency of the electric filter drops on the seventh day of operation to 85.6%, which is due to the appearance in the electric filter to a marked back corona. It is necessary to make further investigations to increase the efficiency of the equipment.Translated from Ogneupory, No. 3, pp. 15–17, March, 1971.     

燃油微乳化技术及其研究进展

燃料油燃烧不充分不但造成资源浪费更主要的是尾气排放的有害物质引起环境污染。论述了燃油乳化的必要性、燃油产品绿色途径和乳化燃油的缺点,并详细论述了微乳化燃油长期稳定、制备简单、燃烧效率高等优点、微爆的燃烧机理、抑制NOx生成机理和水在微乳液中的作用,总结了微乳化燃油研究现状和加入水裂解催化剂、增大水含量形成水包油型微乳液的发展趋势。     

Mechanism of wood combustion: 1. Flue gas analysis

The mechanism of open system combustion of dry wood, a solid carbonaceous fuel of a high volatile matter content, was studied through a quantitative monitoring of the stack flue gas. Combustion is in three stages. The first stage is an accelerated burning during which the chemical composition of the burned fractions is virtually constant, approximates that of the initial dry wood and is independent of air flow rate. The second stage involves a rapid change in chemical composition of the burned fractions. In the third stage the chemical composition of the burned fractions is again virtually constant and independent of air flow.     

Dead burning magnesite in shaft furnaces with natural gas

Conclusions The dead burning of raw magnesite in pieces of 40–250 mm size has been achieved in shaft furnaces heated by natural gas. The quality of the burned magnesite and the economics of the furnace working were improved in comparison with those obtained when using fuel oil.Translated from Ogneupory, No. 3, pp. 16–18, March, 1969.     

连通容器内预混气体爆炸过程的实验研究

对连通容器内预混气体爆炸过程进行实验研究,具有重要的科研和实用价值。本文通过实验室内自制的实验仪器详细研究了不同的点火位置、初始压力、初始浓度对连通容器内预混气体爆炸压力的影响。结果显示,在大容器中点火,会引起更大的爆炸压力;压力上升速率也增大很快。初始浓度对连通容器内预混气体爆炸的影响基本与单个容器中的影响一致。当初始压力增大时,连通容器的爆炸压力也随着一起增大,而且小容器比大容器增加更快。因而,在工业中,最有效的方法是隔爆,在容器和管道接口设置隔离装置,使爆炸不能通过管道传播。     

催化裂化干气中乙烯制汽油工业实验

目前国内催化裂化干气是石油化工合理利用的盲点,大部分都作为燃料烧掉,利用率过低,造成资源浪费,找到合理利用的途径迫在眉睫。本文着重介绍了催化干气中乙烯制汽油技术的工业试验和工业应用情况。结果表明干气制汽油技术是切实可行的,有利于提高经济效益,具有很好的应用前景。     

后石电厂选择性催化还原(SCR)脱硝装置的应用

介绍了后石电厂SCR脱氮技术的基本原理、系统组成及加装SCR装置对空气预热器和引风机等相关辅机的设计和材料选型等方面造成的影响,并给出了相应的建议。对后石电厂的尾部烟气进行脱氮处理可以大量减少氮氧化物的排放,显著改善环境。     

Development of can-type low NOx combustor for micro gas turbine (fundamental characteristics in a primary combustion zone with upward swirl)

A low NO_x combustor for kerosene-fueled micro gas turbine based on a new concept was proposed, and the combustion characteristics of the prototype combustor were investigated. The new concept combustor consisted of primary and secondary combustion zones, and they were connected by a throat. A swirler was set between the primary and secondary combustion zones. In order to enhance the recirculation of burned gas in the primary combustion zone, the combustion air was introduced through the swirler and forced to flow upward to the combustor bottom, from where fuel spray was supplied through a nozzle. An optimum configuration of the primary combustion zone such as length of primary zone, swirler vane angle, diameter of throat, etc. were investigated to achieve high combustion stability and low emission in wide ranges of fuel flow rate and excess air ratio. The optimum value of each part in the primary combustion zone was found out by measuring fundamental combustion characteristics such as lean combustion limit, flame luminosity, exhaust gas composition and combustion gas temperature.     

Toxicologic and Physicochemical Characterization of High-Temperature Combustion Emissions

Particles and combustion gases produced by two different high-temperature combustors, which burned pulverized coal and a No. 2 fuel oil-fly ash slurry, respectively, at adiabatic flame temperatures greater than 2400 K, were characterized. Effluent samples were taken at locations along the product gas stream and within the stack. Measurements of the particle size distributions, number concentrations, and gas species concentrations were made. The toxicity and mutagenicity of the effluent particles were determined. A large number of submicrometer particles were found in both cases of high-temperature combustion. The product emissions differed significantly in their particle size distribution and final chemical composition from those of conventional combustion systems having lower combustion temperatures.     

Method for predicting the performance of an internal combustion engine fuelled by producer gas and other low heating value gases

Gasification can be seen as a process in which solid biomass is converted into a mixture of combustible gases, which complete their combustion in a second device, usually a reciprocating internal combustion engine (RICE). Downdraft moving-bed gasifiers coupled with RICE are a good choice for moderate quantities of available biomass, the equivalent of up to 500 kW of electric power. The producer gas must be mixed with additional air in order to have a stoichiometric mixture to fuel the RICE. To predict the engine performance working with such a fuel, a so-called Engine Fuel Quality (EFQ) parameter has been developed by the authors. This parameter considers the combined effect of stoichiometric air–fuel ratio and stoichiometric mixture heating value, both depending on the producer gas composition. The estimation of engine power made by using the EFQ parameter indicates that power at full load is reduced at about two-thirds of the maximum obtained with a conventional liquid fuel. A more detailed prediction of engine performance requires the use of computer simulation of several types. The authors have used successfully a two-zone thermodynamic model to predict engine performance. Model results include the fraction of mass burned, the pressure and temperature evolution, and pollutant emissions. The detailed results for power confirm the first order prediction based on the EFQ parameter.     

铝–油酸/正庚烷基纳米浆体燃料液滴着火燃烧特性

采用液滴悬挂法研究了正庚烷液滴、油酸/正庚烷混合燃料液滴、含20wt%纳米铝粉的铝–油酸/正庚烷基纳米浆体燃料液滴在不同温度下(600~800℃)的着火燃烧特性。用高速摄像机观测液滴进入管式电阻炉后的着火燃烧过程,使用热电偶记录液滴周围的气相温度变化,同时通过对应的温度曲线计算液滴的着火延迟时间。结果表明,纳米铝粉和油酸的添加均能降低正庚烷液滴的着火延迟时间。随温度升高,正庚烷、油酸/正庚烷混合燃料、铝–油酸/正庚烷基纳米浆体燃料液滴的着火延迟时间显著降低,但变化趋势逐渐趋于平缓。铝–油酸/正庚烷基纳米浆体燃料液滴的着火延迟时间与环境温度满足阿累尼乌斯方程。与纯正庚烷、油酸/正庚烷混合液滴的燃烧过程相比,铝–油酸/正庚烷基浆体燃料液滴的燃烧过程有显著差异,其燃烧经历3个阶段：正庚烷稳定燃烧阶段、正庚烷微爆炸阶段和表面活性剂微爆炸阶段。铝–油酸/正庚烷基浆体燃料液滴燃烧时间延长,火焰熄灭后又复燃,且燃烧过程中发生剧烈的火焰形变和铝颗粒溅射现象,大部分铝以团聚体形式在第三阶段完成氧化还原反应。     

基于内燃机余热回收联产系统变工况特性分析

回收天然气内燃机的排气余热是提高能源利用率的有效手段。提出一种回收排气余热的朗肯循环耦合吸收式制冷循环的联产系统,并针对内燃机多变工况特点,构建联产系统的变工况仿真模型开展变工况特性研究。结果表明,当内燃机工况从100%下降到40%时,联产系统的当量效率下降2.14%,系统总能效率增量仅下降1.64%,说明此联产系统具有很好的工况适应性。在40%工况下,制冷循环由于溴化锂溶液的结晶而不能正常运行。研究结果为联产系统的实际运行提供理论指导。     

Modeling and simulating combustion and generation of NOx

This paper deals with the modeling and simulation of combustion processes and generation of NO_x in a combustion chamber and boiler, with supplementary combustion in a gas turbine installation. The fuel burned in the combustion chamber was rich gas with a chemical composition more complex than natural gas. Pitcoal was used in the regenerative boiler. From the resulting combustion products, 17 compounds were retained, including nitrogen and sulphur compounds. Using the developed model, the simulation resulted in excess air for a temperature imposed at the combustion chamber exhaust. These simulations made it possible to determine the concentrations of combustion compounds with a variation in excess combustion.     

Estimation of the velocity of transient concentration waves in nonuniform reacting disperse media

A method for estimating the velocity of convective transient concentration waves in reacting disperse media is proposed. Theoretical foundations of the method, which are illustrated by the wave transport of a dissolved gas component in a nonhomogeneous flow of rising drops when the gas can react with the continuous phase, are discussed.     

Ignition of the drops of coal–water fuel in a flow of air

The ignition of the drops of coal–water fuel (CWF) in a high-temperature gas (air) flow was experimentally studied. The conditions and fundamental characteristics of the ignition (ignition delay times) were found. The effects of a number of factors (drop sizes and ambient temperatures) on the conditions of ignition were examined. Based on the results of experiments, a physical model was formulated for the processes of thermal preparation and ignition of CWF drops. The experimental delay times of the ignition of CWFs were compared with the theoretical values (obtained with the use of a previously developed mathematical model).     

氧化钙-二氧化碳循环系统脱碳的分析研究

采用燃料氧燃烧直接供热的氧化钙-二氧化碳双床循环系统已经被研究开发,用于从电厂尾气中脱碳。本研究基于实验和化学反应工程原理建立了分析模型,用于系统地研究循环特征,氧化钙活性衰减,燃料及其炉内热利用率的影响。基于模型推导获得了重要参数:最小循环热损失和最小热需求量,以及对应的固体循环比。它们都受供热燃料灰分和含硫量的影响,也受脱碳率的影响。显然最佳固体循环比介于二者之间。另一个重要参数是燃料在炉内的热利用率。高的热利用率不仅降低燃料需求量,降低其灰分和含硫的影响,降低氧的需求量及其辅助功,而且提高蒸汽循环的发电效率。一个发现是热需求量在临界固体循环比接近无穷大,这就限制了固体循环比的可操作范围, 以及燃料的灰分和含硫量。建立的分析模型和推导直接提供了这些变量之间的关系和范围。     

Experimental and numerical studies of mixing and flame stability in a micro-cyclone combustor

A 30-W-class micro-cyclone combustor was developed as a heat source for a 1-W thermoelectric power generator (TPG). Methane gas was used as a fuel instead of liquefied fuel in this feasibility study for convenience. The combustion stability of the combustor was measured, and the flame shapes were visualized experimentally. Numerical simulations were performed to examine the details of the flame structure and flame stabilization mechanism inside the micro-cyclone combustor. The micro-cyclone combustor burned the supplied fuel stably inside the combustion chamber in the range where the combustor generated 30 W of heat energy. The mixing and flow characteristics of non-reacting and reacting flows in the combustor were examined using the simulation results. The mixing of the fuel with air in a non-reacting flow field was enhanced by increasing the equivalence ratio for a fixed fuel flow rate. For non-reacting flow, a recirculation region and a small negative axial velocity region near the injection ports were formed. The recirculation region became wider with decreasing equivalence ratios. For reacting flows, however, the recirculation region disappeared and the only small negative axial velocity region was formed near the fuel injection ports. The flame was stabilized inside the combustor because the flame base was anchored near the negative axial velocity region near the fuel injection ports.     

Gas/Flüssig-Reaktoren

Gas-liquid reactors . The gas hold-up in bubble columns increases in proportion to the gas flux density in the homogeneous flow regime and rises less than proportionally in the heterogeneous flow regime. Both the gas and the liquid axial dispersion coefficient increase with gas flow. Gas phase dispersion becomes more intensive with increasing liquid viscosity, while liquid dispersion drops slightly. Experimental results for mass transfer in low viscosity liquids show that the two-range turbulence model best fits experimental data. When aerating highly viscous Newtonian and non-Newtonian liquids, mass transfer in the liquid phase is well described by known relations valid for very low bubble-Reynolds number and very high Schmidt number.     

生物柴油特性及作为混合燃料添加剂的研究

论述了生物柴油优越的理化特性,可作为柴油的替代燃料,并讨论了生物柴油作为乙醇（甲醇）与柴油或汽油混合燃料的添加剂情况.通过溶解度测定及三相图实验数据表明生物柴油作为乙醇与柴油添加剂,促溶效果较好;对于生物柴油-汽油-乙醇体系来讲,三者可以任意比例混合,可改善汽油的燃烧性能;对于生物柴油-柴油-甲醇体系,效果不理想.     

二级旋流气液分离装置设计与流场特性模拟

通过有效体积转化进行分离器尺寸设计,针对高气液比工况设计了一种二级旋流气液分离装置,基于液滴在旋流场中的破碎特性及Navier?Stocks方程的简化求解建立一种分离器直径的校核方法,通过实验验证了该校核方法有效. 通过CFD方法对简化的分离装置内部流场的非对称性进行分析. 结果表明,旋转流场的不稳定程度随入口面积和升气管直径减小而减小,入口速度不影响流场的不稳定程度,不同的长宽比在相同的入口面积下对内部流场的非轴对称性无显著影响,但单独增加入口的长、宽或二者同时增加使入口面积增大,将使分离器筒体横截面与入口截面的面积比KA减小,增加内部流场的非轴对称性.