模拟移动床改进进料模式提高生产效率的模型化研究(英文)

A new feeding mode for a simulated moving bed(SMB)is proposed.The outlet stream from zone Ⅱ is collected at regular intervals.The concentration of the solution is increased by dissolving raw materials and then fed to zone Ⅲ as the feed stream during the next collection interval. In this feeding mode,the concentration of the stream fed to zone Ⅲ is identical to that of original feed,while in a conventional SMB,the feed is diluted by mixing with the outlet stream of zone Ⅱ before feeding to zone Ⅲ.The new feeding mode increases the inlet concentra tion of zone Ⅲ.A modeling investigation shows that higher inlet concentration of zone Ⅲ increases the height of concentration band in SMB,improving the separation performance significantly.In comparison with the traditonal feeding mode,the new feeding mode increases the productivity by 23.52% and decreases the solvent consumption by 22.56%,so as to increase the raffinate and extract concentrations by 53.17% and 20.38%,respectively.The collection interval for the outlet stream from zone Ⅱ has no effect on the separation performance after reaching the steady state,so that the collection interval can be increased to make the operation more convenient.     

椭球形颗粒动力效应模型(DEM)构建方法的比较(英文)

Discrete element model was developed to simulate the ellipsoidal particles moving in the moving bed.Multi-element model was used to describe a ellipsoidal particle,the contact detection algorithm of ellipsoidal particle was developed,and both contact force and gravity force were considered in the models.The simulation results were validated by our experiment.Three algorithms for representing an ellipsoidal particle were compared in macro and micro aspects.The results show that there exists big difference in the microscopic parameters such as kinetic energy,rotational kinetic energy,deformation,contact force and collision number which leads to the difference of macroscopic parameters.The relative error in the discharge rate and tracer particle position is the largest between 3-tangent-element representation and experimental results.The flow pattern is similar for the 5-element and 3-intersection representations.The only difference is the discharge rate of 5-element representation is larger than the experimental value and that of the 3-intersection representation has the contrary result.Finally the 3-intersectionelement representation is chosen in the simulation due to less computing time than that of the 5-element representation.     

折流式旋转床的流体力学行为(英文)

As a high gravity (HIGEE) unit, the rotating packed bed (RPB) uses centrifugal force to intensify mass transfer. Zigzag rotating bed (RZB) is a new type of HIGEE unit. The rotor of RZB consists of stationary discs and rotating discs, forming zigzag channels for liquid-gas flow and mass transfer. As in RPBs, some hydrodynamic behavior in RZB is interesting but no satisfactory explanation. In this study, the experiments were carried on in a RZB unit with a rotor of 600 mm in diameter using air-water system. The gas pressure drop and power consumption were measured with two types of rotating baffle for RZB rotors, one with perforations and another with shutter openings. The circumferential velocities of gas were measured with a five-hole Pitot probe. The pressure drop decreased rapidly when the liquid was introduced to the rotor, because the circumferential velocity of the liquid droplets was lower than that of the gas, reducing the circumferential velocity of gas and the centrifugal pressure drop. The power consumption decreased first when the gas entered the RZB rotor, because the gas with higher circumferential velocity facilitates the rotation of baffles.     

模拟移动床改进进料模式实验研究

常规的模拟移动床色谱II区流出液与原料液在线混合进入III区,会导致进料浓度的降低,从而影响模拟移动床的生产效率。而新的进料模式,将II、III区断开,定期收集II区流出液,在II区流出液中溶解一定量的原料,使其浓度与初始进料浓度相等,然后在下一个周期中作为原料进到III区。以α-生育酚的制备为研究对象,对模拟移动床新型进料模式和传统进料模式进行对比,结果表明,新型进料模式比传统进料模式生产效率提高了53.04%,溶剂消耗减少了35%。同时,在新型进料模式下α-生育酚在SMB系统内部的最高浓度提高了77.24%,而非α-生育酚在SMB系统内部的最高浓度提高了67.31%。在改进进料模式下,α-生育酚的生产能力得到了提高。     

模拟移动床吸附分离(Ⅰ)—计算模型

模拟移动床技术已有效地用于多种液态烃类的分离。文章从吸附平衡角度出发,分析模拟移动床物料流动形式。把模拟移动床分为三个系统进行分析和计算,分别建立各系统的计算模型,并通过整个床层的物料衡算得到关联。从而有可能达到床层设计、操作工艺的最优化运算。     

旋转填料床中硝酸吸收NO_x的实验研究(英文)

Absorption of NOx into nitric acid solutions was studied in the presence of ozone by using a rotating packed bed (RPB) contactor. The influences of operating parameters, such as high gravity number, amount of ozone, gas velocity, liquid spray density and inlet concentration of NOx, on the removal efficiency of NOx were investigated, among which the high gravity number and ozone amount are more important. Ozone was introduced to oxidize HNO2 to HNO3 to prevent the decomposition of HNO2 in the liquid phase. The high gravity number presents the effective external force for enhancing the mass transfer of ozone from gas phase to liquid phase. Under the experimental condition, the removal efficiency of NOx is higher than 90% and the concentration of nitric acid product exceeds 45%.     

超重力旋转填料床中柠檬酸钠缓冲液吸收二氧化硫(英文)

Absorption of SO2 from a SO2/air mixture with sodium citrate buffer solution was investigated using a rotating packed bed(RPB) in laboratory scale.The effects of operating parameters,such as the rotation speed of RPB,liquid-gas ratio,inlet gas flow rate,inlet concentration of SO2 in flue gas,sodium citrate buffer concentration and initial pH of absorption solution,on the SO2 concentration in the absorption solution or removal efficiency of SO2 were examined.Incremental rate of sulfate radical ions in the absorption solution was also examined.Experimental results indicate that the efficiency of this regenerative process will be improved by using RPB under appropriate operating conditions,and the generation of SO2-4 will be restrained in the process in RPB.     

进料浓度对模拟移动床雌马酚对映体分离效能的影响

通过调节模拟移动床（SMB）进料口处样品初始进样浓度,可以有效提高目标产物的单位产量。以分离雌马酚对映体作为研究对象,在一定的纯度约束条件下,同时对产品纯度和单位产量进行多目标优化。基于多目标优化所获得非劣解,比较和分析了5个进样浓度对SMB生产性能的影响。     

模拟移动床吸附分离(Ⅱ)——调优运算

分析模拟移动床物料流动形式,分别建立各系统计算模型,编制了计算机程序。通过计算机的调优运算,对模拟移动床各区的级数、所需吸附剂量、进出各物料量和组成等工艺条件进行计算,计算结果与现场考核数据一致。     

旋转填充床中沉淀过程的模型及实验验证(英文)

A mixing-precipitation model based on the modified coalescence-redispersion model was presented to describe the flow, mixing, nucleation and growth in a rotating packed bed (RPB). The model was coupled with population balance, mass balance and crystallization kinetics. It predicted well the influence of coalescence probability, which represents the mixing intensity among drop-lets, on the particle number density, supersaturation and mean particle size of the produced precipitates. The effects of the radial thickness of packing, liquid flow rate and rotating speed on the product particle size were also investigated. The results indicate that the needed radial length of packing is short for sparingly soluble substance precipitation (about 40-50 mm in this work), and the mean particle size of precipitates decreases with the increase of rotating speed and liquid flow rate, respectively. The validity of this model was verified by experiment on BaSO4 precipitation in RPB.     

旋转填充床内高黏介质脱挥过程的传质模型(英文)

A mass transfer model for devolatilization process of highly viscous media in rotating packed bed(RPB) was developed based on penetration theory and mass conservation.Before establishing the model,some mass transfer experiments of thin film were conducted in a designed diffusion cell including vacuum and feeding system. In this study,acetone was used as the volatile organic compound(VOC) and syrup as the highly viscous media.The thickness of thin film was changed by using different liquid distributor.It was found that bubbling played an important role in the devolatilization.The correlation of diffusion coefficient of acetone in highly viscous dilute solution was proposed.The relative error between predicted and experimental data was within the range of ± 30% for diffusion coefficient of acetone in syrup.A comparison of experimental data of RPB with model indicated that the relative error was within ± 30% for efficiency of acetone removal.     

浓缩硼-10模拟移动床色谱分离的放大研究

为实现SMB色谱分离硼-10的工业化,进行氯型硼特效树脂排代色谱法富集硼-10的SMB放大实验研究。放大研究中色谱柱的内径由原来的1.0 cm放大到8.5 cm,树脂也由原先的均匀小颗粒(平均为230μm)改为商用粒度范围颗粒(平均为780μm)。SMB放大色谱分离系统连续运行了约60 d(129次端口切换),取得富集度31.11%~40.31%的硼-10酸固体68 g。根据Fujii理论公式,对SMB放大分离系统中不同端口切换次数时的富集因子ε和理论踏板高度HETP进行计算,结果发现ε和HETP在整个实验过程中均保持常量,其值分别为ε=0.009 2±0.000 7,HETP=0.83±0.10 cm。与前期小型SMB分离系统的实验结果相比,ε变小,HETP变大,分离效果变差明显。     

元素汞在实验室模拟脱硫装置中再析出的影响因素(英文)

Elemental mercury(Hg0)re-emissions from slurries and solutions were evaluated in a lab-scale simulated scrubber.Oxidized mercury(Hg2 +)standard solution was injected into the simulated scrubber at a desired rate to simulate absorbing and dissolving of Hg2 +in the flue gas across wet flue gas desulfurization(WFGD)systems. PS analytical mercury analyzer was used to continuously determine Hg0re-emission concentrations in the carrier gas from the scrubber.Sulfite ion in the slurry of CaSO3 was validated to reduce Hg 2+to Hg 0,while no Hg 0 re-emission occurred from slurries of CaSO4 and CaO.Transitional metal ions with low chemical valence such as Fe2 +,Pb 2+,Ni 2+, 2 AsO-and Cu +were used to prepare solutions with concentration levels of mmol·L-1.Reduction reaction of Hg2 +to Hg 0was observed from these solutions.Reduction capabilities for the different transitional metal ions in the solutions were:Pb2 +Cu +Fe 2+ 2 AsO-Ni 2+.     

二甲苯模拟移动床分离过程建模与仿真

模拟移动床（SMB）是混合二甲苯分离的重要技术。模拟移动床区域回流比是决定产品质量的关键参数。在真实移动床（TMB）建模方法基础上,结合实际工况数据,建立了模拟移动床吸附分离过程机理模型,并通过分析区域回流比对产品质量的影响,得到不同产品质量要求以及进料品质的情况下区域回流比的操作区间。仿真结果表明,TMB建模方法能较好地描述模拟移动床实际工况。基于机理模型对操作区间的分析结果可以为模拟移动床分离过程的工艺设计和操作提供指导意见。     

模拟移动床分离盐酸度洛西汀的研究

通过HPLC单柱实验,确定了盐酸度洛西汀的拆分条件。采用平衡扩散模型对盐酸度洛西汀在8柱四区模拟移动床上的线性分离过程进行了模拟,考察了切换时间对分离效果的影响。在适宜的操作条件下,达到了较好的分离效果。两种对映体的纯度分别达到99. 67%和99. 62%,回收率分别达到了96. 30%和97. 14%。     

模拟移动床吸附分离对甲乙苯工艺

为了实现C9芳烃中对甲乙苯资源的高效利用,以X型分子筛为吸附剂,以混合甲乙苯为原料,采用液相模拟移动床吸附工艺分离对甲乙苯(p-MEB)与邻甲乙苯(o-MEB)、间甲乙苯(m-MEB)。在操作温度为75℃、操作压力为0. 25 MPa的条件下,在液相模拟移动床吸附分离装置上考察了操作条件对p-MEB吸附分离过程的影响规律,获得优化的p-MEB吸附分离工艺条件为:模拟移动床区域分布采用6-3-4-3模式,切换时间900 s,分配比1. 1,循环比3. 5,脱附剂比9. 3。对于pMEB质量分数为20. 78%的C₉芳烃,优化分离工艺条件下得到的p-MEB质量分数为94. 52%,回收率达到90. 86%。     

奥美拉唑对映体的模拟移动床色谱分离过程模拟

模拟移动床色谱已成为一种重要的手性药物制备技术,其技术关键在于最佳运行点的确定。由于其过程复杂,用数学模型来确定最佳运行点,求解难度大,计算时间长。今以考虑传质阻力与轴向弥散的模拟移动床模型为基础,采用线上求解法,将模型方程沿空间方向离散,得到一组常微分方程,然后运用MATLAB提供的常微分求解器求解这一偏微分方程组,模拟了奥美拉唑对映体的模拟移动床色谱分离过程。研究结果表明,线上求解法结合MATLAB常微分求解器可快速、准确地求解模拟移动床模型,用于模拟移动床色谱分离过程的实时控制与优化。     

应用模拟移动床分离技术提高企业效益

模拟移动床分离技术具有分离专一性强、洗脱剂消耗量小、可连续生产、自动化程度高等优点.这些优点为工业生产带来了巨大的经济效益和操作便利性,比如,缩短分离流程,降低分离工艺的劳动强度和生产成本、增强对有效成份提取的专一性,提高产品收率和品质、改善生产环境,实现清洁生产、从废物中提取高附加值产品等.     

人参皂甙Rb_1的模拟移动床分离

介绍了应用模拟移动床技术分离高含量人参皂甙Rb1的工艺。确定了模拟移动床分离人参皂甙Rb1的操作条件,洗脱剂:V(甲醇)∶V(水)=45∶55;模式:1-4-3;切换时间:360 s;洗脱流速:60 mL/min;萃取液流速:30mL/min;进样流速:3 mL/min;样品质量浓度:0.2 g/mL。讨论了影响模拟移动床分离的主要因素,并与单柱分离工艺进行了比较。     

模拟移动床分离过程及其优化方法研究进展

模拟移动床技术具有产率高、纯度高、过程连续性等优点,适用于多组分体系及各组分性质比较接近的难分离体系,其过程设计和优化工作一直是研究的重点和难点。本文首先对模拟移动床分离机理及其各种变型进行了介绍,其中重点阐述了目前应用广泛的顺序式模拟移动床技术的分离模式和优越性能。在此基础上,总结并分析了模拟移动床领域的各种优化方法和研究进展。从传统的三角形理论开始,总结归纳了三角形理论应用体系,指出其重要地位及局限性。之后依次介绍了基于三角形理论衍生而出的序列二次规划算法、应用较为广泛的驻波设计、体积分离分析和基于遗传算法的过程模拟、多目标优化等多种优化方法。分析结果表明,除多目标优化以外,无论是最传统的三角形理论,还是其他几种优化方法,在参数选择和实验设计等方面都存在诸多局限性,而多目标优化方法已被证明表现更为优异,可以适用于模拟移动床操作模式的各种变型,在未来将具有极大的发展潜力和应用前景。