38室环式焙烧炉改造与烘炉生产

通过对长城铝业公司炭素厂３８室环式焙烧炉的改造，提出了产能和热效率，使焙烧炉的能耗降低，产品质量也大大提高，更好的满足电解厂的需求。     

敞开式焙烧炉节能的理论分析与实践

本文就敞开式焙烧炉在生产过程中的能耗从理论上进行了深入的分析,找出能耗高的主要原因,提出并采用敞开式焙烧炉在确保碳阳极焙烧质量的前提下节能的有效措施,从而使敞开式焙烧炉的能耗在原来的基础上降低了三分之一。     

浅谈阳极焙烧炉炉体的设计优化

阐述了阳极焙烧炉炉体的设计优化,探讨了提高阳极焙烧炉技术水平,降低能耗的方法和措施。     

谈谈阳极焙烧炉的设计节能

笔者从设计者的角度,阐述了阳极焙烧炉的设计,必须从实际出发,充分考虑其实用性,以最低的投入,获得最大的产能,尽可能地降低生产能耗,节约生产成本。同时,介绍了一些提高阳极焙烧炉技术水平,降低阳极焙烧炉能耗的方法。     

阳极焙烧炉工艺操作参数优化实践

分析了国内某厂阳极焙烧炉运行过程中沥青挥发分燃烧效果不佳,能耗偏高的原因,采取了优化调整工艺参数等手段使焙烧炉产品能耗得到了显著降低。     

环式阳极焙烧炉热工过程的数值模拟

通过对环式阳极焙烧炉的热工过程进行系统理论分析, 建立了焙烧炉热工过程的数学模型. 对焙烧炉进行模拟计算的结果表明 焙烧过程中阳极内部温差最大的地方主要集中在炉顶, 应采取相应的措施减少炉顶的热损失以保持阳极焙烧温度的均匀性; 同时, 不同的火焰循环时间和空气渗漏对焙烧的能耗影响较大, 降低火焰循环时间将导致能耗增加, 而降低空气渗漏量则可极大地降低能耗.     

阳极焙烧炉节能的途径

指出结构设计是阳极焙烧炉节能降耗的关键。有了合理的炉体结构,再配以自动控制系统,合理的焙烧周期等条件,就能降低能耗。本文从炉体结构设计、挥发份燃烧、固体蓄热回收、炉体漏风和控制方法等方面,介绍了降低阳极焙烧炉能耗的途径,以及一些有效的操作方法。     

阳极焙烧炉能耗的影响因素

全面分析了工艺操作、焙烧炉设计以及其它有关因素对焙烧炉能耗的影响,指出了当前国内对焙烧炉能耗影响因素认识上存在的误区,对国内今后阳极焙烧炉的设计优化和操作具有借鉴和指导意义。     

电极焙烧炉优化设计探讨兼谈近中期节能目标

综述了自建国以来电极焙烧炉的技术发展状况,在总结近年来新型电极焙烧炉运行经验和问题的基础上,提出优化设计的几个关键问题,如弧形墙、格子砖墙接头形式、有无火井等。针对我国现行电极焙烧炉节能方面的问题,提出了进一步降低能耗的近中期奋斗目标和措施。     

初论氢氧化铝流态化焙烧技术与国内应用

分析了广泛应用于工业生产的三种态化焙烧炉各自的特点和不足，认为液态闪速焙炉炉和循环流态焙烧炉技术成熟、生产稳定性强，气体悬浮焙烧炉能耗指标先进。并提出了引进以流态闪速焙烧炉稍优，消化创新应以气体悬浮为基础。     

敞开式环型焙烧炉的综合测试分析

对敞开式环型焙烧炉进行了综合性的测试分析 ,测定了火道中的烟气成分 ,以及火道和阳极的升温曲线 ,估算了焙烧炉的热平衡。指出促使焙烧时热耗增大的主要原因是预热段空气的严重渗漏以及排烟温度的过高。测试分析的结果还显示 ,沥青挥发分若不能及时从阳极逸出到火道中燃烧将严重影响阳极的焙烧质量。     

Praxair’s dilute oxygen combustion technology for pyrometallurgical applications

Dilute oxygen combustion (DOC) technology uses separate high-velocity fuel and oxygen jets to generate strong in-furnace gas recirculation, producing combustion between the fuel and a highly diluted oxygen and furnace-gas mixture. These very low NOx oxy-fuel burners have been developed and commercially demonstrated in steel reheating furnaces. The burner design meets industry needs for increased productivity and lower operating costs with minimal capital expense and low maintenance. The performance of DOC technology has been measured under laboratory and industrial conditions encompassing both natural gas and coke oven gas firing, and a wide range of furnace temperatures and nitrogen levels that simulate air infiltration. This paper describes the results of the tests using natural gas as the fuel and lists potential applications for DOC technology in the non-ferrous metals industry. For more information, contact A.C. Deneys, Praxair, Inc., Applications Research and Development, 777 Old Saw Mill River Road, Tarrytown, New York 10591; e-mail Adrian_Deneys@Praxair.com.     

Influence of novel cycle concepts on the high‐temperature corrosion of power plants

The aim to reduce CO₂ emissions has triggered the evaluation of new cycle concepts for power plants. CO₂‐capture concepts are also evaluated to add on new and existing power plants. For combined cycle power plants (CCPP), different cycles are investigated such as integrated gasification (IGCC) or oxy‐fuel firing. Besides the difference in combustion compared to a conventional CCPP, the environmental boundary conditions are changed and will affect the oxidation and corrosion life of the materials in the hot‐gas path of the gas turbine and the heat‐recovery steam generator. For the circulating fluidised bed power plants, the biomass co‐firing and the oxy‐fuel firing are also foreseen for CO₂‐emission reduction. The fireside corrosion of the water walls will be influenced by these concepts and the changed fuel. The corrosion risk has been evaluated for two new power plant concepts: combined cycle with exhaust gas recirculation and pulverised coal‐fired boiler with oxy‐fuel firing. Based on this evaluation, the consequences for the testing conditions and the material selection have been discussed in detail.     

对焙烧炉送风的探讨

通过对焙烧炉火焰运行过程、燃料需求特点、逆风特点和过剩空气系数等问题的分析。以及对系统布置方式、风机的选择和送风控制原理等初步探讨，指出焙烧炉逆风必须适应燃料变化和挥发分析出，使通风量能够在一个范围内变动，送风设计应选择能适应这一特点的变风机。最后还对焙烧炉通风存在的几个实际问题进行了讨沦。     

Infiltration kinetics of pressureless infiltration in SiCp／Al composites

The pressureless infiltration kinetics was investigated by plotting the infiltration distance as function of the infiltration time. The effects of key process parameters such as time, temperature, Mg content on the pressureless infiltration of silicon carbide particle compacts were studied and quantified. The preform with high volume fraction SiC was obtained by mixing SiC particles with bimodal size distribution, whose diameters are 5 and 50 btm, respectively. The results show that an incubation period exists before infiltration, the influence of temperature on the incubation time exceeds that of Mg content, infiltration rate increases with the increasing temperature and Mg content, infiltration rate decreases as Mg consumes. A model of macroscopical infiltration and microscopical infiltration of liquid alloy in porous SiC preform was proposed.     

焙烧炉烘炉启动新技术应用

针对焙烧炉烘炉启动传统方法中存在的燃耗高、启动炉室损害大等缺点,提出采用新型工艺技术方案,并成功应用于一34室焙烧炉的烘炉启动工作。结果表明,新技术不仅使整个烘炉启动时间由原计划的45天降低到30天,天然气消耗量降低了37.6%,并且只需一个启动炉室,对焙烧炉本体损害降到了最低。     

AlF3添加剂和焙烧温度对铝电解炭阳极过电位的影响

在实验室制备各类AlF3掺杂试验阳极，在测试其基本物理化学性能的基础上，采用“改进断电流法”进行阳极过电位测试，研究AlF3添加剂和阳极焙烧温度对阳极过电位的影响。结果表明：在一定条件下，阳极中添加AlF3既可降低阳极的空气／CO2反应活性，也可降低阳极过电位；受高温脱S等因素的影响，阳极的电化学活性及其空气／CO2反应活性并未随着焙烧温度的提高相应降低。     

Simulation of molten metal through a unidirectional fibrous preform during MMC processing

The injection of molten metal through a fibrous preform is one of the techniques used to manufacture metal matrix composites (MMCs). The flow of liquid metal through a fibrous preform constitutes a moving boundary problem of fluid mechanics in a porous medium. In the present model, the isothermal infiltration process is considered. The numerical algorithm, based on the body-fitted finite element method (FEM), can precisely deal with the transient and irregular physical domains and calculate the flow behavior. Numerical results show that the infiltration pattern is strongly influenced by the nature of the preform. The injection flow rate under constant applied pressure decreases with the infiltration time. The effect of the preform orientation on infiltration pattern is also discussed. Similarity analysis shows that the infiltration time is inversely proportional to the ratio of applied pressure to liquid viscosity for the same type of preform.     

Potential high temperature corrosion problems due to co‐firing of biomass and fossil fuels

Over the past few years, considerable high temperature corrosion problems have been encountered when firing biomass in power plants due to the high content of potassium chloride in the deposits. Therefore, to combat chloride corrosion problems co‐firing of biomass with a fossil fuel has been undertaken. This results in potassium chloride being converted to potassium sulphate in the combustion chamber and it is sulphate rich deposits that are deposited on the vulnerable metallic surfaces such as high temperature superheaters. Although this removes the problem of chloride corrosion, other corrosion mechanisms appear such as sulphidation and hot corrosion due to sulphate deposits. At Studstrup power plant Unit 4, based on trials with exposure times of 3000 h using 0–20% straw co‐firing with coal, the plant now runs with a fuel mix of 10% straw + coal. Based on results from a 3 years exposure in this environment, the internal sulphidation is much more significant than that revealed in the demonstration project. Avedøre 2 main boiler is fuelled with wood pellets + heavy fuel oil + gas. Some reaction products resulting from the presence of vanadium compounds in the heavy oil were detected, i.e. iron vanadates. However, the most significant corrosion attack was sulphidation attack at the grain boundaries of 18‐8 steel after 3 years exposure. The corrosion mechanisms and corrosion rates are compared with biomass firing and coal firing. Potential corrosion problems due to co‐firing biomass and fossil fuels are discussed.