【作者】 唐林志；

【导师】 张会平；

【作者基本信息】 华南理工大学 ， 化学工程， 2010， 硕士

【摘要】 活性炭微孔发达,比表面积高,吸附能力强,作为一种优良的吸附材料,广泛应用于化工、环保、食品与制药、催化剂载体以及电极材料等领域。在实际应用过程中,一般采用粒状活性炭填充在固定床吸附器或反应器中,这类吸附器或反应器填充颗粒粒径通常为1~4 mm,导致床层传质阻力较大,接触效率低,吸附或反应速率慢,造成流体通过时,由于床层空隙率较小,存在径向扩散严重,压降大等缺陷。在一些应用领域,如滤毒罐应用中,采用传统颗粒装填材料及装填工艺,已很难满足实际需求。因此,开发一种新型高效低阻微纤包覆活性炭复合材料(简称微纤复合材料)替代传统活性炭材料,提高这类吸附反应器的综合性能既具有前沿性,又具有应用价值。本文详细研究了微纤包覆活性炭复合材料的制备、表征以及在催化氧化一氧化碳和降阻技术中的应用。首先,本文选择金属纤维、粒径在80~100目的颗粒活性炭和木质纤维素为原料,采用湿法成型工艺和高温气氛保护工艺制备了微纤包覆活性炭复合材料。分别考察了湿法成型工艺中分散转数、操作时间、抄片加水量和高温气氛保护烧结工艺中烧结温度、烧结时间、烧结压片质量这些工艺参数对微纤复合材料性能的影响,优化了微纤复合材料的制备工艺。实验结果表明:转速为3000 r/min条件下,分散10 min、操作时间在20s以内、抄片加水量为2 L、烧结温度为1050~1150℃、烧结时间为15~30 min、烧结压片质量达到106 g时,微纤复合材料综合性能最优。烧结后颗粒活性炭的比表面积由680m2/g提高到735 m2/g。其次,本文以制备的微纤包覆活性炭复合材料为载体,分析了反应温度、载气中水分以及气体流速对CO在铜、铬、银浸渍炭上的催化氧化性能,考察了CO在微纤复合床中的催化氧化规律。实验结果表明:颗粒活性炭粒径在40~60目,反应温度80℃、载气中不含水分、气体流速在1 L/min时,一氧化碳在铜、铬、银浸渍炭上的转化效率较高,前25 min一氧化碳转化率在40%以上;当微纤复合材料装填量为10%,CO在微纤复合床层上的转化率与传统颗粒活性炭填充的固定床层相比变化不明显;当微纤复合材料装填量为40%时,CO在微纤复合床层中的转化率比传统颗粒活性炭填充的固定床层提高较快,反应进行10 min时,一氧化碳转化率由52.5%提高到58.3%;当微纤复合材料装填量为100%时,一氧化碳在前10 min转化率在32.3%以上,25 min后CO几乎没有转化。最后,本文考察了粒径在40~60目、60~80目以及80~100目三种不同粒径活性炭装填的动力管压降性能;分析了在不同流速条件下,微纤复合材料装填质量10%与40%的微纤复合床与装填粒径在40~60目的传统颗粒活性炭固定床气体通过时的压降变化情况。实验结果表明:粒径在40~60目的活性炭填充的动力管压降最小、粒径在60~80目的活性炭填充的动力管其次、而粒径在80~100目的活性炭填充的动力管压降最大。在流速为1.5 L/min和3 L/min条件下,装填10%与40%微纤复合材料的微纤复合床与传统颗粒活性炭固定床压降性能一样,在6 L/min、9 L/min和10.5 L/min条件下,装填10%微纤复合材料的微纤复合床比传统颗粒活性炭固定床低0.1~0.3 kPa,装填40%微纤复合材料的微纤复合床比传统颗粒活性炭固定床低0.3~0.6 kPa。更多还原

【Abstract】 As an adsorption material with abundant porous structure and high specific surface area,activated carbon has been widely used in chemical industry, environmental protection, foodindustry, pharmaceutics, catalyst carriers and electrode materials, etc. In practice, the particlesize of activated carbon is about 1~4 mm in the process of filling fixed bed adsorber and fixedbed reactor, which led to greater resistance, low efficiency, slow adsorption and reaction rate,and this fixed bed adsorber or fixed bed reactor has small void. When the fluid passes, itcausesradial diffusion seriously and pressure drop greatly.In some applications, for example,canister technology, using the traditional particle packing materials and loading is difficult tomeet the actual demand. Therefore, developing a new microfibrous entrapped activatedcarbon composite to replace the traditional granular carbon in order to increase the overallperformance is a frontier and valuable research area. In this paper, preparation,characterization and application of microfibrous entrapped activated carbon composite wereinvestigated.Firstly,microfibrous entrapped activated carbon composite was prepared by the wetlay-up papermaking process and sintering process used metal fibers, granular activated carbonwith particles size at 80~100 mesh and wood cellulose as raw materials. The influences oftotal rotation, operating time, amount of water, sintering temperature, sintering time andquality of sintering pressed were investigated. The preparation parameters were optimized.The experimental results showed that microfibrous entrapped activated carbon composite hadexcellent performance in the conditions of 3000 r/min, working 10 min,operating time in lessthan 20 s, amount of water at 2 L, sintering temperature at 1050~1150℃, sintering time at15~30 min, quality of sintering pressed at 212 g. After sintering, surface area of activatedcarbon increased from 680 m2/g to 735 m2/g.Secondly, the application of treating carbon monoxide with microfibrous entrappedactivated carbon composite was investigated. The factors of reaction temperature, water vaporin carrier and gas velocity were discussed. The experimental results showed that carbonmonoxide on activated carbon impregnated with copper, chromium, silver had higher conversion efficiency about 40% at 80℃within the 25 min, no water vapor in carrier gas,velocity at 1 L/min when bed loaded granular activated carbon with particles size at 0.4 mm.Microfibrous entrapped activated carbon composite had less effect on oxidation of carbonmonoxide when loaded microfibrous composite at 10%. Microfibrous entrapped activatedcarbon composite had more effect on oxidation of carbon monoxide and increased from52.5% to 58.3% within 10 minutes when loaded microfibrous composite at 40%, comparingwith the traditional particle packing materials. When microfibrous complex bed loadedmicrofibrous composite at 100%, conversion of carbon monoxide was 32.3% within 10minutes, and carbon monoxide was not converted after 25 min.Finally, pressure drop of traditional bed loaded with different carbon particles size at40~60 mesh, 60~80 mesh and 80~100 mesh was discussed. Microfibrous complex bedsloaded microfibrous composite concentration at 10% and 40% were investigated for thepressure drop, comparing with the traditional particle packing materials loading particles sizeat 40~60 mesh. The experimental results showed that the smaller particle size has the greaterresistance. The bed loaded particles size at 40~60 mesh had the least resistance and the bedloaded particles size at 80~100 mesh had the greatest resistance. When the velocity reached1.5 L/min or 3 L/min, microfibrous complex bed loaded microfibrous compositeconcentration at 10% and 40% had the same pressure drop as the traditional particle packingmaterials bed loaded particles size at 40~60 mesh. When the velocity reached 6 L/min, 9L/min and 10.5 L/min, the pressure drop of microfibrous complex bed loaded withmicrofibrous composite concentration at 10% decreased 0.1~0.3 kPa and the pressure drop ofmicrofibrous complex bed loaded with microfibrous composite concentration at 40%decreased 0.3~0.6 kPa, comparing with the traditional particle packing materials bed loadedparticles size at 40~60 mesh.更多还原