Reactive pressure swing batch distillation by a new double column system

Ethyl-acetate is generally produced by the esterification reaction of ethanol with acetic-acid. Since the reaction is equilibrium-limited, the use of reactive distillation is an attractive option. A new double-column system is suggested for ethyl-acetate production by applying reactive pressure swing batch distillation. The system was investigated by a feasibility study based on the analysis of reactive and non-reactive residue curve maps. Two different process options were found to be feasible. In the first option, the reactive column operates at the lower pressure (1.01 bar), and the non-reactive column that removes ethyl-acetate from the system operates at the higher pressure (10 bar). The second option allows the reactive column to operate at the higher pressure (10 bar), and the non-reactive column removes water at the lower pressure (1.01 bar). The first process option was studied by rigorous simulation based on less simplifying assumptions using a professional dynamic simulator. The influence of the most important operation parameters was also studied.     

周期全回流间歇精馏中全采出操作时的塔顶浓度平台期(英文)

The total withdrawal operation is an inevitable section in cyclic total reflux batch distillation.In the operation,an interesting phenomenon "overhead concentration platform"(OCP) appears,which is defined as a period of time with high overhead concentrations when the operation is changed from total reflux to total withdrawal.The OCP phenomenon and its influential factors,such as the theoretical stage number,feed concentration,and feed composition,are examined by simulations and experiments.The experimental equipment is a column with random packings.It is shown that the number of theoretical stages influences the OCP more significantly than the other factors.     

Enhanced process comprehension and quality analysis based on subspace separation for multiphase batch processes

Phase‐based subpartial least squares (subPLS) modeling algorithm has been used for online quality prediction in multiphase batches. It strictly assumes that the X – Y correlations are identical within the same phase so that they can be defined by a uniform regression model. However, the accuracy of this precondition has not been theoretically checked when put into practical application. Actually it does not always agree well with the real case and may have to be rejected for some practical processes. In the present work, it corrects the “absolute similarity” of subPLS modeling by a more general recognition that only one part of the underlying correlations are time‐wise common within the same phase while the other part are time‐specific, which is referred to as “partial similarity” here. Correspondingly, a two‐step phase division strategy is developed, which separates the original phase measurement space into two different parts, the common subspace and uncommon subspace. It is only in the common subspace where the underlying X – Y correlations are similar, a phase‐unified regression model can be extracted for online quality prediction. Moreover, based on the subspace separation, offline quality analyses are conducted in both subspaces to explore their respective cumulative manner and contribution in quality prediction. The strength and efficiency of the proposed algorithm are verified on a typical multiphase batch process, injection molding. © 2010 American Institute of Chemical Engineers AIChE J, 2011     

Real‐time control of a semi‐industrial fed‐batch evaporative crystallizer using different direct optimization strategies

This article presents a model‐based control approach for optimal operation of a seeded fed‐batch evaporative crystallizer. Various direct optimization strategies, namely, single shooting, multiple shooting, and simultaneous strategies, are used to examine real‐time implementation of the control approach on a semi‐industrial crystallizer. The dynamic optimizer utilizes a nonlinear moment model for on‐line computation of the optimal operating policy. An extended Luenberger‐type observer is designed to enable closed‐loop implementation of the dynamic optimizer. In addition, the observer estimates the unmeasured process variable, namely, the solute concentration, which is essential for the intended control application. The model‐based control approach aims to maximize the batch productivity, as satisfying the product quality requirements. Optimal control of crystal growth rate is the key to fulfill this objective. This is due to the close relation of the crystal growth rate to product attributes and batch productivity. The experimental results suggest that real‐time application of the control approach leads to a substantial increase, i.e., up to 30%, in the batch productivity. The reproducibility of batch runs with respect to the product crystal size distribution is achieved by thorough seeding. The simulation and experimental results indicate that the direct optimization strategies perform similarly in terms of optimal process operation. However, the single shooting strategy is computationally more expensive. © 2010 American Institute of Chemical Engineers AIChE J, 57: 1557–1569, 2011     

Nonisothermal modeling of heat transfer inside an internal batch mixer

A nonisothermal transient process of temperature increase due to viscous heating was simulated for a 69 cm³ internal batch mixer (BM) using a computational fluid dynamics (CFD) software, Polyflow 3.9 form ANSYS, Inc., to obtain the temporal temperature distribution and characterize the heat transfer between polymer melt and mixer wall. The melt temperature obtained from simulation was verified with experiments. Starting from a uniform temperature of 463 K, when a rotation speed of 5.24 rad/s is imposed, viscous heating caused a maximum temperature rise of 3 K for a polyethylene (PE) resin, and 6 K for a polystyrene (PS) resin. The transient flow fields inside the batch mixer were characterized with velocity profiles and a mixing index parameter, which show that laminar flow dominates inside the mixer while a small percentage of elongational flow, converging flow, and recirculation flow is also present. © 2010 American Institute of Chemical Engineers AIChE J, 2011     

过氧化物DCP母料的研制

研究了采用过氧化物DCP、将DCP制成母料、在DCP母料中加入分散剂、在加入分散剂的母料中再加入助交联剂MAH(顺丁烯二酸酐)这4种条件下LDPE的交联情况，讨论了DCP的加入量对LDPE交联度的影响，同时讨论了交联度随交联时间的变化。     

间歇精馏的操作方式及算法

通过对间歇蒸馏的不同的操作方式的分析，利用逐板计算方法，研究用正、反分段函数插值法和离散点下的数值积分相结合，进行间歇蒸馏的操作型计算，并编写了通用的计算机程序。     

真空间歇精馏分离橙花醇和香叶醇的研究

橙花醇和香叶醇是重要的基础香料,沸点差仅为2℃,具有热敏性。以往研究中应用减压间歇精馏分离橙花醇和香叶醇的混合物,一次精馏得到90%以上的产品收率低(仅为46%),且塔釜温度较高,操作周期长,不宜于工业生产。本文针对沸点差较小的热敏性物系,采用减压高效间歇精馏方法对橙花醇和香叶醇的混合物进行了分离研究。通过考察全回流时间、回流比、加热负荷和压力等操作因素对分离效果的影响,确定了适宜的操作条件,塔顶压力为600Pa～700Pa,塔压降为4800Pa～4900Pa,釜温在150℃～152℃之间,全回流6h,采用20 1,10 1,5 1的变回流比操作。实验结果显示,单塔精馏即可得到含量大于90%的橙花醇和香叶醇,收率在65%以上,提高20%无热分解现象,过程稳定,为工业生产奠定了基础。     

HA—SBR工艺及其在啤酒厂废水处理中的应用

SBR（序批式活性污泥法）和HA—SBR（水解酸化一序批式活性污泥法）与普通活性污泥法相比,具有不产生污泥膨胀、处理效率高、运行可靠、耐冲击强等优点,备受人们关注。论文对SBR和HA—SBR法工作原理、工艺特点及主要影响因素进行了阐述,综述了两种工艺在啤酒废水处理中的应用进展,并展望了其发展前景。     

膜-序批式生物膜法(MSBBR)处理生活污水试验研究

采用膜-序批式生物膜法(MSBBR)处理高校校园生活污水,研究了系统稳定运行后的处理效果.结果表明,系统出水COD平均为44mg·L-1,NH3-N、TN、TP的平均质量浓度分别2、34、8.20、0.326 mg·L-1,对COD、NH3-N、TN、TP的平均去除率分别达到83.4%、87.01%、67.46%、84.34%,且系统具有较强的抗冲击负荷能力.