基于Aspen Plus的褐煤高温烟气和回转管式干燥过程模拟

为了研究高温烟气干燥和回转管式干燥特性,采用Aspen Plus软件对高温烟气干燥和回转管式干燥过程进行流程模拟,并运用能量平衡法和分析方法对2种干燥系统能量利用效率进行分析。结果表明,Aspen Plus能够较好地模拟高温烟气干燥和回转管式干燥过程。烟气和蒸汽温度分别为750和203.1℃时,回转管式干燥的热利用效率为71.27%,较高温烟气干燥高4.04%,而回转管式干燥利用效率为87.68%,较高温烟气干燥高49.33%。随干燥介质温度升高,高温烟气干燥与回转管式干燥热利用效率提高,利用效率降低。     

煤干燥装置热工计算之探讨(续)

"燃料与化工"1995年№3期第64页刊登的"煤干燥装置热工计算之探讨"一文中,介绍了采用煤气燃烧成高温烟气作为干燥介质,并计算出每小时的煤气用量.但是,在工业生产中所设置的燃烧炉通常为两用炉,既可燃烧煤气产生高温烟气,又可燃烧煤产生高温烟气作为干燥介质,为此,现将采用煤燃烧时的计算方法补充如下.     

加热炉热效率提高的途径

WAYOFRAISETHETHERMALEFFICIENCYOFFURNCE1前言管式加热炉是一种火力加热设备，它利用燃料在炉膛内燃烧产生的高温火焰与烟气作为热源，加热炉管内高速流动的介质，使其达到工艺要求的温度。其主要特点是加热温度高（可达1000ap），传热能力大和便于操作管理，它在生产和建设中具有十分重要的地位。实践证明，加热炉效率的高低与节约能源、降低成本有极密切的关系。对于炼油厂常减压蒸馏装置，加热炉是主要耗能设备，其能耗占装置总能耗的80％一83％，因此降低加热炉燃料消耗，提高加热炉热效率是实现装置“低能耗、高效率…     

稻谷就仓低温通风干燥系统生产性实验

中国是稻谷的生产和消费大国，总产量占世界总产的33％左右，居世界第一位。传统的稻谷高温烘干方法介质温度高、干燥生产能耗大、费用高，烘干后稻谷惊纹率高，整精米率降低，严重影响稻谷加工和食用品质。在探索稻谷低温通风干燥特性、综合分析国内外稻谷低温通风干燥特性试验研究成果的基础上，研制了稻谷深层通风干燥系统，确定了立管式多环径向通风干燥工艺路线，通过稻谷就仓通风干燥系统的生产性实验，对通风干燥仓结构性能、稻谷通风前后质量变化规律等进行了测试，验证了稻谷低温通风干燥的科学性与可行性。     

国内外化工简讯

南京推出白炭黑手操新设备江苏科圣高温热管设备制造公司开发的高温热管热风炉，有效地解决了沉淀法生产白炭黑的喷雾干燥造粒难题。该公司采用南京化工大学研制的热管技术生产的高温热管热风炉，主要应用于物料的喷雾干燥。由于高温热管是利用不锈钢作为管壳，采用碱金属作为工作介质而制成，其使用热源温度可保持在500～1200℃。这种热风炉克服了传统燃煤热风炉温度低、排烟温度高的缺陷，使生产的热风温度高达600℃、排出烟气温度200℃以下，设备的干燥效率可提高到80％以上，还可以大幅度降低干燥成本。高温热管热风炉成功地应用于喷雾…     

钛白粉闪蒸干燥工艺中的余热回收应用

利用天然气燃烧产生的热烟气对钛白粉进行闪蒸干燥,可初步得到成品,但需要消耗大量燃料。为了降低热风炉的燃气耗量,对原有工艺增设换热器,从闪蒸干燥袋滤器后的烟气取热,来预热热风炉的助燃空气和二次混合空气,可在满足热烟气需求的同时减少热风炉的燃气耗量。通过对闪蒸干燥工艺改造及实际应用进行分析对比,基本得出热管式换热器在闪蒸干燥工艺中的余热回收效果。     

浆式进料沸腾炉烟气制酸系统的改进

介绍了国内首家浆式进料沸腾炉冶炼烟气制酸系统生产运行几年来的技术改造情况，为今后高温，高三氧化硫含量的冶炼烟气制酸工艺设计与生产提供了可靠的依据。     

速溶泡花碱干燥工艺改进

本文引用实例，介绍了用XRG燃煤风炉出高温空气取代煅烧炉高温烟气作为热介质干燥速溶泡花碱干燥的生产工艺，使产品质量和产量明显提高，成本下降，经济效益上升。     

煤炭高温贫氧燃烧一体化系统的探讨

据调研,各耗能系统的加热炉目前使用的燃料多为天然气和原油,本课题探讨面向煤炭高温气化——高温贫氧燃烧一体化系统的研究.该系统用煤炭高温气化产生的混合煤气为燃料,采用高温贫氧燃烧技术并结合蓄热技术充分吸收烟气余热来保证系统效率.高温贫氧燃烧方式的工业炉窑与采用传统燃烧方式相比,单位燃耗可降低40％,节约了能源,相应地降低了CO2的排放.以混合煤气为替代燃料,实现加热炉系统的节能降耗目的.     

烟气CO_2矿化产品干燥过程能量梯级利用研究

针对50000Nm~3/h烟气CO_2矿化磷石膏联产硫酸铵与碳酸钙工艺,提出了烟气余热梯级利用技术路线。将烟气余热按温度由高到低依次转化为动力以及产品干燥所需热能,动力循环中工质的冷凝则直接作为碳酸钙流化床干燥器的内热源。干燥工段消耗的热量汇集于75℃低温烟气中,利用热循环水直接接触烟气回收该热量为碳酸钙振动流化床预热器供热,同时将降温脱湿后的干燥尾气用作预热器的干燥介质,实现能量的高效利用。     

Thermodynamic Analysis on a Lignite-Fired Power System Integrated with a Steam Dryer: Investigation on Energy Supply System of the Dryer

Lignite is becoming a competitive fuel for power generation with high security of supply and a low price. But a power plant firing lignite directly always has some weaknesses, including low thermal efficiency and high construction investment. Predrying lignite before feeding it to the boiler is a potential method to tackle these weaknesses, and low-pressure steam extracted from steam turbines is considered a competitive heat source for the drying process. In a lignite-fired power system integrated with a steam dryer, the steam extraction is led to the dryer via a connection pipe and depressurization valve. To obtain a stable drying temperature at a variable load of power, steam extraction is often used by the dryer after depressurization, which indeed causes exergy loss. To reduce the exergy loss, the steam extraction was proposed to be supplied to the dryer via a compressor or ejector. Thermodynamic models were developed to calculate the net efficiency of a power system with different energy supply systems. The energy saving boundary—that is, the net efficiency of power system could be increased in some ranges of drying temperature by some energy supply system of dryer—was obtained. Furthermore, the exergy efficiencies were calculated.     

THE RELEASE OF MONOTERPENES DURING CONVECTIVE DRYING OF WOOD CHIPS

ABSTRACT

The release of volatile organic components (VOC) during high temperature convective drying of wood chips was studied experimentally and theoretically. The drying medium was superheated steam with a pressure of two bar. Two different temperature levels of the drying medium, 160 and 180 °C, and two different materials, Scots Pine and Norway Spruce, were investigated. It was found that the main components released consist of various types of monoterpenes, with α-pinene dominating in each of the two materials. The amount released is dependent on the drying temperature as well as the time of the drying process.

In order to describe the release rate of monoterpenes during drying, two separate models, called the communicating and the non-communicating model respectively, were developed. The mechanisms included for the transport of monoterpenes are, in the communicating model, transport by diffusion and with the advective gas and liquid flow within the tracheids and, in the non-communicating model, diffusion within the resin canal system.

The results obtained using the communicating model largely overpredict the experimental results. To avoid this rapid release, additional mass transfer resistance for the transport of monoterpenes between the two canal systems could be introduced. The non-communicating model was found to be useful in explaining the release rate when drying spruce. This model, however, can not distinguish between the two temperature levels studied.     

用高露点空气干燥小木块时挥发性有机物的释放

Emission of volatile organic compounds (VOCs) during drying of wood particles for particleboard manufacture, or for production of refined biofuels, is a potential environmental problem. The aim of this work is to study the emissions of VOCs during drying, and the influence on the emissions by different drying parameters. The experiments have mainly been done in a batch fluidized bed dryer, but measurements have also been done in a, pilot scale, continuous fluidized bed dryer. The parameters studied are air flow rate through the bed, air temperature, air dewpoint, and bed height. Since the present trend in biofuels and particle drying is towards very high dewpoints during drying, some measurements have been made at dewpoints up to 95℃, corresponding to a water content of 3.2 kg water per kilogram dry air. The emissions have been measured in two different ways, online during drying with a flame ionization detector and through wood analyses of the terpene content in the wood particles before and after dryi     

热泵干燥系统温湿度控制实验研究

针对闭式热泵干燥系统非线性,强耦合等特点,将干燥循环分成升温过程和降温过程,并针对不同过程设计了相应的温度模糊控制策略。干燥过程温度、湿度是影响干燥物料品质的关键因素,为了提高干燥物料品质在温度控制的基础上设计了湿度模糊控制方案并给出了温湿度解耦策略。对温湿度的模糊控制效果进行了实验检测。系统运行结果表明：温湿度控制效果显著,温度的偏差控制在±0.8℃,湿度的偏差控制在±3％RH。     

催化裂化催化剂生产过程中分子筛粉碎技术的应用

在催化裂化催化剂生产过程中为了提高超稳分子筛的有效利用率,提升产品质量,使用了一系列超稳分子筛粉碎技术。对超稳分子筛聚集的原因及粉碎技术进行了对比分析,重点分析了介质超细研磨粉碎技术对催化剂质量指标的影响。造成超稳分子筛粒子聚集的主要原因是NaY分子筛合成过程中粒子间相互吸附,后续分子筛交换改性工序对分子筛粒度分布影响较小。介质超细研磨机和干磨粉碎技术对粉碎超稳分子筛效果明显,能够有效降低分子筛粒径,在催化裂化催化剂生产过程中介质超细研磨机的应用效果较好。经粉碎后的超稳分子筛能够明显降低催化裂化催化剂的磨损指数,提高微反活性。     

Heat transfer and drying kinetics of tomato pulp processed by cast-tape drying

Cast-tape drying (CTD) is a process to dehydrate suspensions. This study evaluated the influence of heat source and forced air convection on the drying rate and temperature of tomato pulp during CTD. To this, a pulp thin layer was spread on a flexible support with its lower surface in direct contact with a heat source. Similar drying rates and evaporative capacities were observed for both flexible supports and heating media. Steam simplifies the temperature control and equipment construction. CTD is a suitable process for producing dried tomato pulp in short drying times, resulting from high evaporative capacity.     

Drying Kinetics of Tomato by Using Electric Resistance and Heat Pump Dryers

Drying kinetics of tomato was studied by using heat pump dryer (HPD) and electric resistance dryers with parallel and crossed airflow. The performance of both systems was evaluated and compared and the influence of temperature, air velocity, and tomato type on the drying kinetics was analyzed. The use of HPD showed to be adequate in the drying process of tomatoes, mainly in relation to the conversion rate of electric energy into thermal energy. The heat pump effective coefficient of performance (COP_HT,EF) was between 2.56 and 2.68, with an energy economy of about 40% when compared to the drying system with electric resistance. The Page model could be used to predict drying time of tomato and statistical analysis showed that the model parameters were mainly affected by drying temperature.     

节能环保的玉米真空干燥设备

传统热风干燥设备热效率低，排放到大气中的烟气污染周围环境，干燥玉米破损率高，浪费粮食。利用真空干燥设备干燥玉米，干燥过程要求的温度低，加热介质不直接排放大气，不但没有环境污染，而且余热可回收再利用，可以实现王米在低温下干燥，做到节能环保，同时由温差引起的热应力较小，玉米破损率低，节约了粮食资源。     

机器人清洗机系统的设计

在发动机清洗设备领域,很多汽车厂家考虑使用机器人清洗机作为最终清洗设备。相比传统通过式清洗机,机器人清洗机具备更多的技术优势。机器人清洗机由机器人系统,输送系统,高压系统,干燥系统,过滤系统,冷却系统,除雾系统七大关键模块组成。