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数值积分法求解低浓度甲苯固定床吸附数学模型 总被引:1,自引:0,他引:1
在低浓度范围用直接积分法代替龙格库塔法求解活性炭固定床吸附甲苯蒸气数学模型,预测结果与实验结果比较表明,计算结果与实验结果吻合良好,所建模型可用于低浓度范围内预测其它情况下的穿透曲线 相似文献
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穿透曲线法获取固定床吸附器的传质扩散系数 总被引:2,自引:0,他引:2
研究了煤质活性炭对不同浓度苯酚溶液的吸附,应用固定床吸附动力学模型、非线性回归固定床吸附流出曲线数据,获得了酚类在活性炭上的扩散传质系数。结果发现,酚类的表面扩散系数DS强烈地依赖于入口酚的浓度,随着酚浓度的升高,表面扩散系数增大。采用上述扩散系数理论预测了其他操作条件下的流出曲线,结果表明实验曲线与预测曲线相符甚好,穿透曲线法能可靠地获取液固吸附过程的吸附扩散系数,为吸附工程设计提供有益的帮助 相似文献
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以固相表面扩散模型为基础,研究了活性炭在不同吸附质浓度下单颗粒的吸附速率与吸附量之间的关系,以及颗粒内浓度分布随时间的变化过程。结合文献对LDF模型的假设,认为吸附初期对吸附剂颗粒内浓度分布做抛物线假设误差较大,吸附初期颗粒表面浓度分布梯度偏低,使得吸附速率降低,并提出了改进后的LDF模型,最后结合固相表面扩散模型和活性炭颗粒吸附SO2固定床穿透实验曲线进行了验证。结果表明,采用改进后的LDF模型作为推动力方程的穿透曲线模型能够更加准确地描述实验过程。本文的研究结果能够为活性炭吸附过程提供理论依据和模型参考。 相似文献
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本文采用煤沥青制备了吸附性能良好的球形活性炭,并用动态法研究了苯酚在其上的吸附,获得了苯酚—活性炭体系的吸附等温线及传质扩散系数,这些参数被用于理论预测固定床吸附器的苯酚吸附流出曲线,结果表明实验结果能与理论预测相符甚好,动态法研究吸附能获取对吸附工程设计有益的设计参数。 相似文献
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SO_2在水蒸气和氧共存的条件下与活性炭接触将发生催化氧化反应变为硫酸蓄积在活性炭内部.SO_2在活性炭上的吸附是一种特殊的操作过程,既不同于纯粹的物理吸附又不同于固定床操作.因此,用于这类反应器设计的方法也有所不同.本文建立了计算化学反应存在下吸附现象透过曲线的基本方程式,采用微分反应器进行了吸附等温线和反应速率方程式的测定,并以积分反应器对床层出口处浓度变化进行了检验.本文还对透过曲线的几何形状,床层内部透过曲线随时间的移动和床层出口透过曲线进行了预测. 相似文献
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通过湿法造纸技术制备了微纤包覆活性炭复合材料,研究了甲苯和对二甲苯在基于微纤复合材料结构化固定床上的吸附透过行为. 结果表明,颗粒活性炭被很好地包覆在烧结锁定的三维网络中,活性炭包覆前后的比表面积分别为976和955 m2/g,微孔体积分别为0.261和0.247 cm3/g;甲苯和对二甲苯在单一颗粒碳固定床和结构化固定床上的吸附均展示出竞争吸附特性,在两床层中均是甲苯先透过. 在5%透过浓度下,甲苯和对二甲苯在结构化固定床上的透过时间较在颗粒碳固定床上分别延长了20和30 min,甲苯和对二甲苯分离时间增加了10 min. 采用Yoon-Nelson模型对透过曲线进行拟合,相关系数R2>0.98,甲苯和对二甲苯在结构化固定床上的吸附速率常数分别为颗粒碳固定床的3和1.6倍. 相似文献
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研究了对二甲苯在活性炭固定床上的吸附动力学。考察了初始浓度、气体流量、床层长度等因素对吸附透过曲线的影响。同时,采用Yoon—Nelson模型对吸附透过曲线进行线性回归分析。实验结果表明,随着初始浓度的增大,透过时间缩短,吸附量增大:气体流最对透过曲线的形状影响不大:床层长度基本不影响透过曲线;Yoon-Nelson模型可以较好的模拟固定床吸附过程。 相似文献
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《分离科学与技术》2012,47(7-9):1309-1324
Abstract Thin adsorption media are being investigated for use in a variety of applications including protective clothing for military use and hazardous waste cleanup, as well as in indoor air quality within a variety of filtration media. The objective of this study was to evaluate the dynamics of adsorption of a chlorinated organic gas on activated carbon impregnated meltblown laminates. The adsorption data were collected on a bench scale test stand on an existing battle dress overgarment and an experimental activated carbon impregnated liner material for use in protective clothing. Activated carbon loadings were nominally 40, 80, and 120 g/m2. This paper reviews the results of the study and compares the experimental results to existing adsorption theory. For the organic compound, trichloroethylene, which was studied, a favorable isotherm was found. Although the materials were thin, the media provided a finite breakthrough, defined as a 1% penetration, followed by a gradual breakthrough curve similar to those typically observed in thicker bed adsorption systems. Adsorption isotherms were developed for the activated carbon loaded laminates; the isotherms were of the Freundlich type. A conventional thick bed adsorption model was used to simulate and compare to the results obtained on the activated carbon loaded laminates. Unlike conventional activated carbon beds where the width of the breakthrough curve is a relatively small portion of the bed depth, the breakthrough curves for these thin laminates comprised a significant portion of the bed depth resulting in breakthrough capacities which were substantially less than the overall absorption capacity of the laminates. 相似文献
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采用微波加热再生废弃针剂用活性炭, 通过响应曲面法中模型的优化设计和分析, 研究了再生过程中的3个影响因子(再生温度、再生时间以及物料厚度)对所再生活性炭亚甲基蓝值和得率的影响, 并通过方差分析(ANOVA)研究了各个实验因子或交互作用对活性炭性能的影响。得到实验优化工艺条件为:再生温度700℃, 再生时间18min, 物料厚度20mm, 所再生活性炭亚甲基蓝值和得率分别为187.5mg/g, 65.20 %。此外, 再生活性炭比表面积高达962m2/g, 总孔体积为1.02mL/g, 平均孔径为4.27nm。 相似文献
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Adsorption isotherms of dichloromethane and 1,1,2-trichloro-1,2,2-trifluoroethane on an activated carbon pellet, Norit B4,
were studied. For these chemicals, the Sips equation gave the best fit for the single component adsorption isotherm. The adsorption
affinity on activated carbon was greater for dichloromethane than that of 1,1,2-trichloro-1,2,2-trifluoroethane. An experimental
and theoretical study was made for the adsorption of dichloromethane and 1,1,2-trichloro-1,2,2-trifluoroethane in a fixed
bed. Experimental results were used to examine the effect of operation variables, such as feed concentration, flow rate and
bed height. Intraparticle diffusion was able to be explained by a surface diffusion mechanism. An adsorption model based on
the linear driving force approximation (LDFA) was found to be applicable to fit the experimental data. 相似文献
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《Dyes and Pigments》2013,96(3):689-694
Controlled porosity carbon aerogels are prepared by a sol–gel polymerization method and the prepared materials are used as fixed bed adsorbents for dye removal. The influences of operating conditions and preparation factors on the adsorption of C. I. Reactive Red 2, as a model compound, from aqueous solution were investigated. Many column parameters were estimated at different stages and the Bed-Depth-Service-Time model was used to analyze the experimental data. The results showed that the adsorption bed capacity increased with increasing bed height, decreasing liquid flow rate and decreasing initial dye concentration. Moreover, the work indicated that the adsorption ability of the carbon aerogel could be controlled by adjusting the molar ratio of resorcinol to surfactant and carbonization conditions. In addition, the adsorption capacity could be improved when the carbon aerogel was activated by CO2. The reasons for the difference in adsorption ability could be related to the different pore structure characteristics of various samples. 相似文献
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Aik Chong Lua Qipeng Jia 《Chemical engineering journal (Lausanne, Switzerland : 1996)》2009,150(2-3):455-461
Steam-activated carbons from oil–palm shells were prepared and used in the adsorption of phenol. The activated carbon had a well-developed non-micropore structure which accounted for 55% of the total pore volume. The largest Brunauer–Emmett–Teller (BET) surface area of the activated carbon was 1183 m2/g with a total pore volume of 0.69 cm3/g using N2 adsorption at 77 K. Experimental tests on the adsorption of phenol by the activated carbons were carried out in a fixed bed. The aqueous phase adsorption isotherms could be described by the Langmuir equation. The effects of the operation conditions of the fixed bed on the breakthrough curve were investigated. A linear driving force model based on particle phase concentration difference (LDFQ model) was used to simulate the fixed bed adsorption system. The model simulations agreed with the experimental data reasonably well. 相似文献