考虑不同产品选择性目标的乙醇胺反应精馏塔模拟与优化

提出以环氧乙烷和液氨为原料,水为催化剂,反应精馏塔合成乙醇胺的工艺。分别以一乙醇胺（MEA）和二乙醇胺（DEA）的选择性最大为目标,探讨了在同一反应精馏塔中实现不同产物选择性目标的可行性和可达到的最大选择性。研究在Aspen Plus模拟软件上进行,通过考察操作压力、水进料量、进料氨烷比、再沸比、环氧乙烷进料位置等参数对反应精馏的影响规律,取得实现不同产物选择性目标的参数优化调节方法。研究表明,大的氨烷比、水进料量和再沸比有利于提高MEA选择性,小的氨烷比、水进料量和再沸比则有利于提高DEA选择性,在优化条件下,MEA选择性可达70.30%,DEA选择性可达41.89%。与文献方法比较,采用反应精馏合成乙醇胺具有明显的优越性和操作柔性。     

An optimisation approach for increasing the profit of a commercial VGO hydrocracking process

In this paper, an optimisation approach is proposed to increase the profit of a commercial hydrocracking unit called Isomax. To represent the system, a full‐lump kinetic model incorporating the flow rate of fresh vacuum gas oil (VGO), bed temperatures, recycle flow rate and the catalyst life is developed. This model is capable of predicting the yield of all products, and it improves with respect to the previous works by considering LPG and light gases, fresh VGO and recycle streams as separate lumps. After developing and validating the model, the profit function of the plant, including the value of the products, fresh feed and hydrogen, as well as energy expenses, is optimised by manipulating the bed temperatures, flow rate of fresh VGO and combined feed ratio (CFR) whilst all process limitations and operating constraints are taken into account. During two years of study and considering all mechanical and operational constraints, the results confirm that the decision variables, generated by the optimisation package, can increase the gross profit of the Isomax process to about 8.17%, which is equal to $5.6 million of net profit annually. © 2012 Canadian Society for Chemical Engineering     

泡沫分离技术的实验研究——回收废液中的金

<正>泡沫分离是一种新的分离技术,在国外研究工作已取得了不少成果.Jorne和Rubin在研究金属离子泡沫分离的基础上,提出的Goug chapman扩散双电层理论,阐述了利用相反电荷的金属离子与表面活性剂离子之间的静电吸引作用,达到金属离子的泡沫分离.Rubin和Lapp、Charewicz和Grives等人通过对泡沫分离金属离子的研究表明:pH值是一个重要的影响因素.同时,离子强度可以改变表面活性剂的选择性.Bruner和Stephan采用泡沫分离方法脱除洗涤剂厂排放的一级及二级污水中的表面活性剂,试验结果表明:塔式泡沫分离装置比槽式装置有更高的脱除率.     

Optimal design of a four‐zone simulated moving bed process for separation of homoharringtonine and harringtonine

A simulated moving bed (SMB) technology was applied to the separation of homoharringtonine (HHT) and harringtonine (HT), which were known to have the potentiality of being used as anti‐cancer agents. First, a series of pulse injection experiments were performed for estimation of the adsorption isotherm and mass‐transfer parameters of HHT and HT. The estimated parameters were utilised in the SMB optimisation tool based on the standing wave design method. From the optimisation tool prepared, the SMB operating parameters (zone flow rates and step time) that led to the highest throughput were obtained under the constraints of product purities (=99.0%) and pressure drop (≤1000 psi). Such an optimisation work was then extended to determine an optimal size of the adsorbent particle for the SMB of interest. The results showed that a particle size of 29 µm was the optimal one for maximising the SMB throughput under the conditions that the column configuration was 2–2–2–2 and the length of each column was 25 cm. If the SMB had the particle size other than 29 µm, its throughput was limited by either the maximum operating pressure or the mass‐transfer efficiency. Finally, an efficient procedure of removing a mobile‐phase additive (ammonium formate) from the product stream of the aforementioned SMB system was developed using a liquid–liquid extraction (LLE) technique. From the results of this study, it was confirmed that the SMB process coupled with a LLE procedure could be highly effective in separating HHT and HT with high throughout and high purity.     

内部热耦合精馏塔基于非理想物系的最优评价

Internal thermally coupled distillation column(ITCDIC) is a frontier in energy saving distillation research. In this paper, the optimal assessment on the energy saving and the operating cost for ITCDIC of nonideal mixture is explored. An evaluating method is proposed, and the pertinent optimization model is then derived. The ethanol-water system is studied as an illustrative example. The optimization results show that the maximum energy saving in ITCDIC process is about 35% and the maximum operating cost saving in ITCDIC process is about 30%,as compared with a conventional distillation column(CDIC) under the minimum reflux ratio operating; the optimal operating pressure of the rectifying section is found to be around 0.25 MPa; the effects of the feed composition,operating pressure and the heat transfer rate on operation are also found and analyzed. It is revealed that ITCDIC process possesses high energy saving potential and promising economical prospect.     

麦芽糖醇纳滤浓缩过程中膜的污染和清洗再生

采用纳滤方法对麦芽糖醇进行提纯和浓缩,可以节约大量的能耗。文中系统研究了该纳滤过程中操作条件对膜污染的影响,并对膜的清洗和再生效果进行了考察。实验结果表明,膜的污染程度随操作压差和原料液质量分数的增大而加剧,随循环流量和操作温度的升高而减轻。另外,采用常压、循环流量为100—120 L/h,40℃左右的去离子水冲洗30 m in,可达到满意的效果,再将被污染的膜浸泡36 h,基本能使膜纯水通量恢复到使用前的状态。     

旋转式能量回收装置的启动与运行特性

能量回收装置是降低反渗透海水淡化（SWRO）系统运行能耗和制水成本的关键设备之一。本文开发并试制了一种具有新型端盘结构的旋转式能量回收装置,并对其启动方式进行了研究优化,测试分析了装置的动密封性能和效率特性,并对装置连续运行稳定性进行了考核。结果表明,旋转式能量回收装置在转速增至额定值后再进行升压操作的启动方式下驱动扭矩最小;装置泄漏量随操作压力增高而增大,在6.0 MPa时,为0.58 m3/h;在转速为500 r/min、处理量为8.0 m3/h及操作压力为6.0 MPa时,装置连续运行稳定,能量回收效率为93%。这些研究结果对旋转式能量回收装置的开发和工程应用具有一定的指导意义。     

乙酸甲酯与甲醇共沸物催化精馏水解工艺

以乙酸甲酯与甲醇共沸物为原料,采用阳离子交换树脂为催化剂,研究了乙酸甲酯催化精馏水解工艺。在实验中以捆扎包作为催化剂的装填方式,系统地研究了催化精馏段和提馏段的高度、进料位置、进料中含甲醇、水酯物质的量比、回流进料比和空速等对酯分解率的影响,获得了最佳的工艺条件。分析了传统的水解分离工艺,提出了可行的新工艺。在最佳工艺条件下,新工艺系统的能耗比传统的固定床工艺降低39.99%。     

Optimisation-based design method for membrane-assisted separation processes

This paper presents a design method for membrane-assisted separation processes based on the concept of process superstructure optimisation, which should be applied to the separation of azeotropic mixtures. The main features of the proposed method are as follows: (i) detailed rate-based modelling of all unit operations; (ii) experimental model identification for membrane separation; (iii) application of an evolutionary algorithm. This method allows the simultaneous determination of optimal process configuration, equipment design and operating conditions for membrane-assisted separation processes.A case study for the separation of a ternary mixture of acetone, isopropyl alcohol and water in a hybrid pervaporation-distillation process is presented using the optimisation-based design method. Detailed rate-based models for the unit operations involved were implemented in a generic process model and necessary membrane model parameters were determined experimentally in a laboratory-scale device for the hydrophilic polymeric membrane Pervap™ 2201D from Sulzer Chemtech. After the identification of an appropriate process superstructure, the process configuration, dimensions of equipment and operating conditions required for the optimal hybrid pervaporation-distillation process were determined simultaneously. The optimisation criterion was the cost for purifying one ton of acetone. The results show that the developed method can be applied successfully for this complex mixed-integer non-linear optimisation problem.     

Grey water treatment and simultaneous surfactant recovery using UF and RO process

The membrane-based grey water treatment for grey water reuse and surfactant recovery is presented in this research paper. Grey water from washing machine discharges having turbidity and used surfactant was processed through the polymeric ultrafiltration (UF) membrane to remove the turbidity. The UF treated grey water is further purified by reverse osmosis (RO) membrane for surfactant recovery and water reuse. The surfactant trapped inside the RO spiral wound membrane module is recovered through various membrane physical regeneration techniques such as backwashing, simultaneous backwash–back-flush and ozone back-flush. Among this, backwash–back-flush is found to be effective process for surfactant recovery. The methodology for optimising surfactant recovery is captured by studying effect of various operating parameters such as feed detergent concentration, backwash pressure, backwash temperature and back-flush flow rate. By implementing optimal process conditions, the integrated UF and RO membrane process is able to produce 300 L of reusable pure water and 80 L of concentrated detergent solution and 20 L of turbid water while treating 400 L of grey water discharges. Maximum surfactant recovery of 82% is obtained while treating grey water which consists of 720 ppm of total dissolved solids (detergent) and 45 ppm of surfactant. The extent of UF and RO membrane fouling is determined by measuring the pure water flux before and after the grey water treatment. The membrane performance is found to be stable when membrane is regenerated by backwash–back-flush technique for RO and gravity backwash for UF membrane.     

扩散渗析法从钛白废酸中回收硫酸

针对钛白废酸的回收,在静态扩散条件下测定了硫酸、硫酸亚铁在阴离子交换膜中的渗析系数以考察膜的分离性能。进一步考察动态扩散操作参数如流量、流量比、停留时间等对回收率及回收酸浓度的影响。研究表明,使用的阴离子交换膜具有良好的分离性能,酸盐分离系数达23.6,在水酸流量比维持在1～1.1,废酸流量维持在0.6L·h-1左右的条件下,硫酸回收率大于85%,硫酸亚铁透过率小于7%。     

常规及创新高压凝液回收流程对比

塔里木盆地地区的英买、迪那等大型高压凝析气田目前仅对原料天然气进行了烃水露点控制,重烃回收率低,经济效益没有实现最大化,对此类气田进行凝液回收可显著提升气田的经济效益。现今适用于高压天然气凝液回收的流程主要为HPA（high pressure absorber）流程,本文在HPA流程基础上提出两种改进流程,即改进Ⅰ型流程和改进Ⅱ型流程。并通过SQP（sequential quadratic programming）算法以单位能耗最低为目标函数对3种流程进行操作参数优化, 并通过能耗分析表明：3种流程具有不同原料气贫富和压力适应范围,在贫气条件下,原料气压力在7000~8000kPa范围内,改进Ⅰ型比HPA流程更节能,而当原料气压力高于7500kPa时,改进Ⅱ型流程能耗开始低于前两者,且随原料气压力增加,节能效果更加明显。而对于富气,改进Ⅱ型流程能耗最高,改进Ⅰ型与HPA流程区别不明显。     

Drying of Biomass in a Conical Spouted Bed with Different Types of Internal Devices

The drying of sawdust was studied in a conical spouted bed pilot plant in order to adapt this feed for the pyrolysis process. Air at different temperatures was used and the effect of sawdust particle size and operating gas velocity was studied. Batch operation was performed with no internal device and with nonporous and open-sided draft tubes in order to ascertain the optimum configuration of the contactor. Although the nonporous draft tube required the lowest minimum spouting velocity, its performance was poor due to deficient gas–solid contact. Configurations with open-sided draft tubes and with no internal devices had higher efficiencies because of their better contacts. An increase in air temperature resulted in a reduction in drying time but the operating conditions need to be fine-tuned to ensure proper energy efficiency.     

Multi-objective optimization of simulated countercurrent moving bed chromatographic reactor for oxidative coupling of methane

A comprehensive optimization study on a simulated countercurrent moving bed chromatographic reactor (SCMCR) is reported in this article for oxidative coupling of methane (OCM) reaction. The selection of the operating parameters such as the switching time, make-up feed rate, methane to oxygen ratio in feed, length of columns and flow rates in different sections are not straightforward in an SCMCR. In most cases, conflicting requirements and constraints govern the optimal choice of the decision (operating or design) variables. An experimentally verified mathematical model was selected to optimize the performance of the SCMCR for OCM. A few multi-objective optimization problems were solved for both existing setup and at design stage. The optimization was performed using a state-of-the-art AI-based non-traditional optimization technique, non-dominated sorting genetic algorithm with jumping genes (NSGA-II-JG), which resulted in Pareto optimal solutions. It was found that the performance of the SCMCR could be improved significantly under optimal operating conditions.     

环丁砜萃取精馏过程模拟分析及工艺参数优化

以环丁砜-烃类相平衡数据和NRTL-RK热力学方法为基础，对环丁砜萃取精馏过程进行了全流程模拟和工艺操作参数优化。综合考虑各个操作变量及其关联，提出了基于局部耦合参数迭代优化的整体协同优化的策略。通过文献数据回归和Aspen Plus物性估算系统相结合，补充修正了缺失的模型参数，并以此模拟分析了各关键操作参数对环丁砜萃取精馏过程能耗和分离效果的影响。结果表明：当萃取精馏塔操作压力为0.17 MPa，溶剂回收塔操作压力为0.05 MPa时，贫溶剂最佳温度为100℃，原料饱和气相进料的最佳进料位置为第50块塔板；溶剂回收塔最佳回流比为0.33；最佳进料位置为第6块塔板，汽提水量为2853 kg·h^-1。优化后，装置最小热公用工程由1.158 GJ·t^-1下降至0.802 GJ·t^-1，节能效果显著。     

机械蒸汽再压缩蒸发系统的性能分析

机械蒸汽再压缩（MVR）蒸发系统是一种新型高效节能蒸发技术。它有多个单元设备组成,每个操作节点的控制都对系统运行的稳定性和节能效率至关重要,其中包括进料温度、蒸发压强、蒸汽压缩比、冷凝液温度等。若操作条件不当,不仅会大大降低蒸发效率而且会对设备和管路造成损害。本文建立了一套充分利用能源的MVR蒸发工艺流程,并通过理论分析对每个操作节点进行了质量和能量衡算,同时利用Aspen Plus模拟软件建立了系统的流程模拟图。通过对操作单元的变量控制,研究了循环蒸汽量、补充水的量与进料温度、冷凝液温度、蒸汽压缩比以及蒸发压强等之间的变化关系。由数据分析可得：原料在饱和液体时进料最佳,冷凝液的温度应保持与蒸发温度的有效温差在5～8 ℃时较好,压缩机的蒸汽压缩比控制在1.8～2.2较为合理。同时可利用冷凝液和浓缩液的余热对原料预热,补充水也可从冷凝液中直接取用。     

内翅片管中堵塞芯管直径优化的数值模拟

采用可实现的k-ε湍流模型和壁面函数法对带不同直径堵塞芯管的内翅片管内空气的湍流流动和换热特性进行了数值模拟,利用试验数据检验了计算方法的正确性。在对不同流量下改变芯管直径进行数值模拟的结果表明：在一定流量下,芯管外径与外管内径之比存在着一个最佳值,使单位压降、单位翅片面积下的换热量最大,而且随着流量的增加,最佳芯管外径与外管内径之比呈减小趋势。在本文所研究的参数范围内,这一最佳比值在0.5-0.625之间。同时也对在相同压降条件下进行了数值计算,结果表明,当芯管外径与外管内径最佳比值为0.4-0.56左右时,单位翅片面积下的流量和换热量之积达最大值。这一结论为内翅片管的优化设计提供了重要依据。     

快速变压吸附制氢工艺的模拟与分析

目前工业上主要通过变压吸附技术从蒸汽甲烷重整气中制取氢产品气。然而,能源需求量的快速增加使得传统变压吸附技术在产量方面的不足越发明显。为此,进行了快速变压吸附从蒸汽甲烷重整气中制取氢气的模拟研究。采用活性炭和5A分子筛作为吸附剂,并以测得的原料气中各组分在两种吸附剂上的吸附数据为基础,进行了六塔快速变压吸附工艺的数值模拟与分析。在分析了塔内温度、压力和固相的浓度分布后,探究了进料流量、双层吸附剂高度比以及冲洗进料比三个操作参数对于快速变压吸附工艺性能的影响,结果表明：原料气组成为H₂/CH₄/CO/CO₂=76%/3.5%/0.5%/20%,吸附压力为22 bar（1 bar=10⁵ Pa）,解吸吹扫压力为1.0 bar,处理量为0.8875 mol·s^-1,吸附剂床层高度比为0.5∶0.5,冲洗进料比为22.37%时,可获得H₂纯度99.90%,回收率69.88%,此时H₂产量为0.4713 mol·s^-1。相比之下,氢气纯度为99.90%时,尽管PSA工艺回收率为83.40%,但处理量只有0.39 mol·s^-1,因此H₂产量仅为0.2472 mol·s^-1。     

Vapour permeation applied for the separation of water from organic compounds and gases using asymmetric polyetherimide/polyvinylpyrrolidone capillary tubes

Asymmetric integrally skinned capillary tubes were produced from the polymers PEI (polyetherimide) and PVP (polyvinylpyrrolidone) for vapour permeation modules which were applied for the separation of water from organic compounds and gases. Water treatment and recovery of desirable organic compounds was achieved. The capillary tubes had intrinsic permeability coefficients of 7.5 × 10^?7 mol/m²·s·Pa for water and 1.6 × 10^?9 mol/m²·s·Pa for 1-propanol for a 1:1 mass ratio vapour feed mixture under pyrolysis conditions. The vapour was fed at the interior of the capillary tubes with total pressure of 30 kPa; the permeate total pressure was 14 kPa, and the temperature was 86°C. Modules, with surface areas up to 1.0 m², were constructed and tested with feed flow rates as high as 4 kg/h with a process development unit. Tests were performed with the vapours from wood chips and contaminated soils subjected to vacuum pyrolysis.     

用于细颗粒分离的水力旋流器的压力特性研究

对用于细颗粒分离的水力旋流器的压力特性 (压力降及压降比 )与流量、分流比、旋数、溢流口和底流口直径及气液比等主要参数之间的关系进行了深入的研究与分析。研究发现 ,水力旋流器内部压力降分别随流量、分流比、旋数及气液比的提高而加大 ,压降比则分别随流量、分流比、旋数的提高而降低。随着溢流口直径的加大 ,水力旋流器的溢流压力降减小 ,而压降比也随之降低 ;随着底流口直径的加大 ,底流压力降减小 ,压降比随之升高。分析可知 ,减少旋流器能耗的有效方法是降低旋数 ,或者减少混合介质中的气液比