固定床吸附器工艺设计计算择优

本文以常州第二化工厂树脂吸附法处理含酚废水的实验数据为基础,详细介绍了固定床吸附器工艺设计的各种方法的计算过程,经计算比较,发现传质模型法较为科学和合理,为统一固定床吸附器的工艺设计计算打下了基础。     

边流效应对固定床吸附器穿透曲线的影响

在半工业吸附装置上实验研究了边流效应对固定床吸附器穿透曲线的影响,建立了非定态二维数学模型描述这种影响．实验结果表明,在床径／粒径比为90时,固定床内边流效应对穿透曲线影响仍很大,中心与壁面穿透时间相差可达4h,模型预测结果表明,实验结果与预测结果能很好吻合．     

穿透曲线法获取固定床吸附器的传质扩散系数

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     

SO_2在活性炭床层中的透过曲线

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．     

液固体系固定床吸附器流出曲线预测模型──活性炭吸附水中酚的研究

建立了液固体系的固定床吸附预测模型,并用正交配置法获得了模型方程的数值解,实验测定了苯酚在活性炭上的静态和动态吸附数据,采用Marquadt法优化固定床吸附流出曲线数据,得到了不同浓度条件下的表面扩散系数及其变化规律,并据此预测了其他操作条件下的穿透曲线,预测曲线与实验结果相符甚好．     

薄平板型固定床吸附器及其在循环通风管路系统中的应用

介绍了薄平板型固定床吸附器在循环通风管路系统中的使用特性和应用效果。该吸附器通过内置数片小间距的平行薄网板,整体安装在循环通风管路系统内来完成气体净化和吸附。该吸附器具备气固两相接触面积大、床层气阻小、结构简单和操作方便等特点,非常适合于相对封闭环境内有害气体的清除。     

数值积分法求解低浓度甲苯固定床吸附数学模型

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     

固定床吸附器水蒸气解吸过程研究

针对低浓度甲苯活性炭固定床吸附 ,对水蒸气解吸载甲苯活性炭固定床作了实验和理论研究 ,测定了水和甲苯在直径 5 0 0 mm,高 15 0 0 mm的固定床中的分布。活性炭取样点在轴向上七个点采样 ,活性炭中甲苯及水含量用 Karl Fisher法测量。活性炭在 15 0℃ ,5 0 Pa条件下解吸。建立了适用于模拟固定床水蒸气解吸的均相模型 ,并对实验结果进行模拟计算 ,结果表明 ,所建模型与实测结果能很好吻合     

DIFFUSION MODES IN A DIFFUSION-CELL ADSORBER

1 INTRODUCTIONDiffusion-cells have been widely used for the measurement of the effective diffusivitiesin porous catalysts.Compared with other methods,diffusion-cell presents itself as asimple,fast and reliable technique and its response curve is very sensitive to the valueof effective diffusivity of the porous catalyst.     

洋茉莉醛最佳电解合成条件的电化学法选择

用电化学方法测定反应体系的极化曲线，通过分析极化曲线得出电解合成洋茉莉醛的最优条件。在此条件下实际合成洋茉莉醛产率为９１％。     

热泵吸附器中传热传质过程的研究

对吸附式热泵循环系统中的传热传质进行了理论分析和实验研究,建立了吸附器中热传导方程.计算求解值与实验结果相一致,说明了吸附器中的传热速率控制了热泵循环速度.据此,对吸附器中强化传热肋片进行了模拟分析,作为吸附器优化设计的理论依据.     

乙烯氧乙酰化固定床反应器的模拟与催化剂分布优化

采用拟均相一维和二维模型对乙烯氧乙酰化工业固定床反应器进行了数学模拟,结果表明:反应器进口气温即为热点温度,可以进一步提高催化剂活性和生产能力.当催化剂活性达到现活性的3倍时,传统的反应器将出现热失控(飞温).采用分段填装高活性催化剂的优化分布,可以大大降低反应器的热敏感性,提高反应转化率和选择性.例如,用两段填装催化剂平均活性(?)=2的反应器代替一段填装催化剂的反应器时,热点温度降低了13.9℃,乙烯转化率和乙烯转化为醋酸乙烯的选择性分别提高了1.46%和1.41%.     

空分装置吸附器出口二氧化碳含量超标的原因及改造

分析分子筛吸附器出口空气中二氧化碳含量超标的原因,通过模拟计算．提出将低温甲醇洗的二氧化碳尾气改至从锅炉烟囱排放的改造方案,对化工装置的布置提出建议。     

DETERMINATION OF MASS TRANSPORT PARAMETERS FOR FIXED-BED ADSORBERS

An innovative technique has been developed for determination of external (“film”) and internal (“intraparticle”) mass transport parameters associated with uptake of solutes by porous solids in fixed-bed adsorbers. These parameters are required for predictive modeling of the dynamics of such systems as activated carbon columns and ion exchange beds. Current methods for evaluation of film transfer coefficients and effective intraparticle diffusivities involve correlation procedures and separate batch-reactor measurements of adsorption rates, respectively. These methods frequently introduce and compound significant errors in subsequent predictive modeling Tor full-scale process design. The present work develops a method by which, on the basis of the characteristics of breakthrough curves measured in specially designed micro-columns, more accurate and reliable simultaneous determinations of both film transfer coefficients and effective surface diffusivities can be done. Verification of the procedure is demonstrated by the agreement of predictions generated from a mathematical model, in which mass transfer coefficients determined from the micro-column technique are used, with experimental breakthrough data for larger scale adsorbers.     

DETERMINATION OF MASS TRANSPORT PARAMETERS FOR FIXED-BED ADSORBERS

An innovative technique has been developed for determination of external (“film”) and internal (“intraparticle”) mass transport parameters associated with uptake of solutes by porous solids in fixed-bed adsorbers. These parameters are required for predictive modeling of the dynamics of such systems as activated carbon columns and ion exchange beds. Current methods for evaluation of film transfer coefficients and effective intraparticle diffusivities involve correlation procedures and separate batch-reactor measurements of adsorption rates, respectively. These methods frequently introduce and compound significant errors in subsequent predictive modeling Tor full-scale process design. The present work develops a method by which, on the basis of the characteristics of breakthrough curves measured in specially designed micro-columns, more accurate and reliable simultaneous determinations of both film transfer coefficients and effective surface diffusivities can be done. Verification of the procedure is demonstrated by the agreement of predictions generated from a mathematical model, in which mass transfer coefficients determined from the micro-column technique are used, with experimental breakthrough data for larger scale adsorbers.     

MEASUREMENT ERRORS PROCESSING BY COVARIANCE ANALYSIS FOR AN IMPROVED ESTIMATION OF DRYING CHARACTERISTIC CURVE PARAMETERS

ABSTRACT

The aim of this paper is to show the interest of the covariance analysis applied to measurement error in the particular case of the identification of a drying characteristic curve from experimental drying data. The modelisation of drying by use of the Drying Characteristic Curve (DCC) method is first presented with usual specifications (power function, critical moisture content …). The experimental procedure used to obtain drying curves and the data processing are detailled and analysed. Measurements errors are identified at the first step of the procedure and their effects on the estimation error of the exponent α of the power function are estimated. Three different methods for estimating α are presented under their matrix form: the least square method and two methods based on the «Gauss–Markov» or «Maximum likelihood» theorem, firstly under a simplified form suited if the estimation errors are uncorrelated and secondly under a complete form suited even if the estimation errors are correlated. These three methods are applied to experimental results obtained with ginger roots drying. The value of the exponent α of the power function and then the distances between the three corresponding theoretical drying curves (representing product water content vs. time) and the experimental points are studied. It is shown that in this particular application, the complete Gauss–Markov method leads to the better fitting and that the simplified Gauss–Markov method, since it is a priori non appliable in this case where errors are correlated, gives quite better results than the oridnary least squares method. The covariance matrices of the estimation errors of reduced water content, reduced drying rate and exponent α are also presented in order to show the correlations existing between the measurement errors of each variable during a drying cycle.     

径向流固定床反应器的流动特性研究及结构参数的合理选择

径向流固定床反应器的操作状态和反应效果在很大程度上取决于反应器内穿越催化剂床层径向气流沿反应器轴向分布的均匀程度，亦即床层内催化剂负荷的均布程度。本文对此类反应器内的流动特性进行了研究，对立了描述反应器内流动规律的基本运动方程。研究结果表明，径向气流的轴向分布情况与反应器的流动结构型式、反应器内分流流道与合流流道截面积的比值、催化剂床层的阻力系数以及反应器的高径比等参数有关。并提出了如何合理选择反