模拟连续式振动流化床内传热传质的研究

在理论分析的基础上,将间歇模拟连续干燥的热质传递模型应用于振动流化床。测定了低气速(u＜u_(mf))下氧化铝大粒子在振动流化床干燥过程中的传质、传热系数,得出相应的关联式。为研究连续式振动流化床内传热提供了一种简便易行的方法。     

振动流化干燥性能的研究

本文首先对小型连续式振动流化床干燥实验装置的工作原理作了说明,并就振动流化条件进行了理论分析。在此基础上,对振动流化床的振动参数和床层温度分布进行了测定及讨论。我们选用活性炭和阳离子交换树脂这两种颗粒物料分别在振动流化床上作了大量干燥性能实验,分析研究不同工况对干燥速率的影响。经系统总结,找出了强化干燥的四大因素。     

振动流化床(VFB)干燥性能及传热特性的研究

以易粘结的工业级细硫铵为研究对象,研究了振动流化床的干燥性能及传热特性。分析了各操作参数对硫酸铵恒速干燥速率的影响,并导出了经验方程;测定了硫铵细粒子在振动流化床中恒速干燥阶段的传热系数,并得出传热关联式。模型计算值与实测值能较好吻合。     

振动流化床干燥分区供热方式研究

基于由小试结果回归得到的煤炭振动流化床干燥动力学数学模型及传热方程、热平衡方程,建立了煤炭表面水干燥所需热量在振动流化床干燥机长度方向上变化的数学模型,该模型表明,煤炭表面水干燥所需热量沿干燥机长度方向呈负指数急剧减少.根据这一特点,讨论了干燥机长度方向等速不等温进气、等温不等速进气、不等温不等速进气3种分区供热方式.采用床面积为1200mm×200mm的振动流化床干燥机进行了中间试验,结果表证明,所得模型与试验结果相符,即采用分区供热方式可降低干燥机出口气体温度和干燥能耗.     

流化床谷物干燥模型的研究

在实验研究的基础上,应用数理统计的方法,建立了流化床干燥玉米的回归教学模型,并对所确定的流化床干燥模型进行了实验验证,证明该模型能较准确的描述流化床干燥玉米时的干燥规律．此模型可为流化床干燥玉米的研究提供理论依据．     

振动流化床的分选特性

研究了振动流化床的流化特性及分选性能,分析了矿粒在振动流化床中的受力情况,分析了影响矿物按床层密度分层的主要参数,揭示了振动流化床的分选机理。试验结果表明：在适当的工艺及操作条件下,振动流化床床层密度均匀稳定,各密度最大相对误差仅0．32％,加重质宏（Ep值）达0．07,为细粒煤的分选提供了一条新的干法分选途径。     

新型直线振动干燥筛分机的振动特性及热工分析

直线振动干燥筛分机是替代振动流化床的理想设备，它把干燥和筛分两种工艺结合起来，大大提高了生产能力。本对直线振动干燥筛分机的振动特性及热工方面进行了详细的分析和阐述。     

载体流化干燥设备的参数研究

通过传质分析,论述了载体流化干燥设备的干燥过程,给出了振动载体流化床干燥石墨的传热参数     

煤炭外水分布规律及其对流化床分选的影响

在揭示煤炭外在水分基本分布规律的基础上,分析了水分在气－固流化床中的传递行为及其对气－固流化床选煤过程的各种影响因素,提出了不同工艺条件下应控制的水分参数．介绍了一种适合于粗粒煤快速干燥的新技术．该技术可灵活解决入选煤的外水问题,干燥速度快、效率高、成本低     

物料在振动力场流化床中的分离

我国2／3以上的煤炭资源分布在西北等干旱缺水地区，煤发的高效干法分选技术十分必要，基于振动流化床的分选特性，在80mm×200mm×2000mm连续式振动流化床分选系统上研究了不同条件下物料在床层中的分离规律及分选效果，结果表明：流化床的似流体特性、水平方向的激振力以及流化床的溢流作用是入选煤在床层中连续分层和移动的动因，在本试验条件下，振动方向α=40°，有效分选带长1850mm时，可以发挥振动流化床的最大分选效能，可能偏差E值达0．075，可以实现细粒煤的连续有效分选．     

振动流化床床层压降理论分析与实验研究

从振动流化床床层压降的物理意义出发,得出了振动流化床床层压降模型。提出振动流化床床层压降-流速曲线上存在第一、第二流化段,相应速度为第一、第二临界流化速度。并在二维振动流化床内,以不同粒径的玻璃珠为床料进行了实验研究,分析了振动及其它操作条件对床层压降的影响,并将模型计算得到的压降与实验结果进行了比较,结果表明模型预测与实验结果有较好的一致性。实验关联了振动能量传递系数的数学表达式,得到第一、第二临界流化速度时床层压降,并与其他研究者的结果进行了对比分析,结果显示本文的模型能得到更为可靠的预测结果。     

通气振动流化床干燥器振动参数的制定

本文研究了在通气条件下振动流化床干燥器振动参数的制定方法,通过对气流和振激力双重作用下物料粒子的受力分析,建立和求解粒子运动方程,提出了通气振动流化床最大抛掷指数的计算式,将计算结果与工业振动流化床抛掷指数的实际值作了比较,表明,实际值约为最大值的８０％。     

宽分布大颗粒振动流化床流体力学研究

描述了宽分布大颗粒振动流化床流化过程中的五种典型状态，指出三层床结构是宽分布大颗粒振动流化床的一个主要特征，讨论了宽分布大颗粒振动流化床的空气动力学特性。     

21世纪高效干法选煤技术的发展

详细讨论了洁净煤分选技术的意义和现状,各种干法分选方法的特点以及空气重介质流化床选煤技术的优越性,空气重介质流化床选煤技术具有分选精度高,投资少,环境污染小,分选密度调节范围宽等特点,在该技术发展的基础上,在小于6mm细粒级振动流化床,三产品双密床层流化床,大于50mm大块煤深床型流化床以及小于1mm微粉煤摩擦电选技术等方面也取得了可喜的进展,在21世纪的洁净煤技术发展中,300到0mm全粒级煤炭的高效干法分选技术的研究与开发是非常重要的。     

潮湿煤炭干法深度分级研究新进展

论述了煤炭干法深度分级新技术－振动流化床气力分级技术的原理、特点、试验及应用。振充化床气力分级在原理与方法与与机械筛分完全坏同,它没有筛网,细粒产物是通过振动流化床中上升气流的夹带分离出来,不存在筛孔堵塞问题,可进行６～０ｍｍ内任一粒度分级,如３ｍｍ分级等,当原煤外水的质量分数小于等于９．５％时,分级效率达８０％～９０％,气力分级得到的粉煤灰分比用筛子筛出的粉煤灰分低１％～４％。振动流化床气力分级     

Experiment research on grain drying process in the heat pump assisted fluidized beds

A heat pump assisted fluidized bed grain drying experimental system was developed. Based on this system, a serial of experiments was performed under four kinds of air cycle conditions. According to the experimental analysis, an appropriate drying medium-air cycle for the heat pump assisted fluidized bed drying equipment was decided, which is different from the commonly used heat pump assisted drying system. The experimental results concerning the drying operation performance of the new system show that the averaged coefficient of performance (COP) can reach more than 2.5. The economical evaluation was performed and the power consumption for removing a kilogram water from grains was about 0.485 kW·2222h/kg (H2O), which shows its reasonable commercial efficiency and great application potentiality in future market.     

Combined Removal of Surface Moisture and Dust from Feed Coal for Coal Dry Cleaning with an Air-solid Fluidized Bed

A demonstration plant and a commercial plant employing coal dry cleaning technology with an air-solid fluidized bed were built in China. The operation practice of these two plants shows that the surface moisture and the fines or dust of feed coal must be well controlled as low as possible. For this purpose, a new process of combined removal of surface moisture and dust from feed coal using a vibrated fluidized bed dryer was investigated in a batch test apparatus and a pilot test system. A mathematical model on drying kinetics of coal surface moisture was developed and three empirical formulas of the model coefficient involving the main operating variables were determined based on the test results from the batch test apparatus. The mathematical model shows that the surface moisture retained in coal during drying decreases exponentially with drying time. According to this model, a new divisional heat supply mode, in which the inlet gas of higher temperature was introduced into the fore part of the dryer and the inlet gas of lower temperature into the rear part of the dryer, was employed in the pilot test system. The pilot tests show that 1） the new divisional heat supply mode is effective for lowering down the average temperature and reducing the total heat loss of the outlet gas off the dryer, 2） the moist coal of about 60 g/kg surface moisture contentcan be dried to about 10 g/kg, and simultaneously the fines （〈1mm in diameter） adhering to the surface of coarse coal particles are completely washed off by the gas flow.     

胶体多孔介质的缓苏-间断干燥工艺研究

以胶体多孔介质胡萝卜切片为物料,以干燥后产品的含水量和β-胡萝卜素保留率为质量指标,研究了物料在静态干燥、动态干燥以及缓苏-间断工艺干燥处理时的产品质量变化规律．结果表明：动态干燥过程中,物料与加热介质的接触面积大,干燥速率较高;缓苏-间断工艺使物料中的剩余水分得以重新分布,消除了物料的表面硬化,可以更快地去除物料中的水分,且β-胡萝卜素的保留率最高．此研究结果可以有效地指导工业生产．     

AFB-MFC系统有机基质降解及产电模型

为了探明厌氧流化床微生物燃料电池(AFB-MFC)产电及有机基质降解之间的关系,基于AFB-MFC阳极系统物料平衡和微生物的增长建立了有机基质降解数学模型,并基于进水流量、外电阻及有机基质浓度建立了产电模型,通过AFB-MFC系统处理高浓度有机废水试验对有机基质降解模型和产电模型进行了验证。AFB-MFC系统有机基质降解动力学模型为q=0.607S/(398.82+S),产电模型为:U=96485S/8*Q·[6×10-6S-0.0133]·Rex。     

Study on drying and combustion process in grate-CFB incinerator

The drying and combustion process in the combined grate and circulating fluidized bed (grate-CFB) municipal solid waste (MSW) incinerator was investigated experimentally and mathematically. The drying grate bed was simulated by a muffle furnace, which could be controlled at a constant temperature level. The kind of wastes, thickness of waste layer fed and temperature were chosen as the adjustable parameters to study their effect on the drying process. The experimental results indicated that the hydrophilic wastes were more difficult to be dried than the hydrophobic wastes. The higher the temperature is the easier the waste is to be dried. The thinner waste layer is favorable to drying the waste. The pyrolysis experiment in the furnace showed that the higher temperature level could reduce the conversion rate of carbon to carbon monoxide. The semi-empirical mathematical model that included the bed material distribution submodel, volatile matter release submodel, carbon particle combustion submodel and so on was proposed. A 260 t/d grate-CFB incinerator was modeled and the model predicted bulk density agreed with the measured value from industrial field test. The predicted flue gas (e.g. CO₂, CO) concentration deviated slightly from the industrial test data. The parameters and variables used in the model were determined by the experiments or practical field test. This model can be used to design the grate-CFB incinerator and guide its operation. Supported by the National Natural Science Foundation of China (Grant No. 50776007)