酵母悬浮液进料时膨胀床空隙率和粒径分布的动态变化

引言 膨胀床吸附技术可以直接从细胞破碎液(未澄清液)中提取目标产物[1-3],而无需预先进行固液分离操作,具有快速、高效和集成化的特点.在实际应用中,料液中细胞(碎片)的存在将会影响到膨胀床的床层稳定性和操作性能[4-6].     

膨胀床吸附层析技术基础性能研究进展

膨胀床吸附层析技术兼有流化床和填充床层析的优点,不需预先除去料液中的颗粒而可以直接从料液中吸附目标产物。但该技术还不成熟,操作还有很大的不确定性,为了解其基础性能,掌握其膨胀和吸附机制,本文从膨胀床流体力学性能、吸附性能、吸附剂与细胞和细胞碎片之间的相互作用等方面,对近年来国内外膨胀床基础性能的研究进行了综述。     

膨胀床吸附层析技术基础性能研究进展

膨胀床吸附层析技术兼有流化床和填充床层析的优点,不需预先除去料液中的颗粒而可以直接从料液中吸附目标产物。但该技术还不成熟,操作还有很大的不确定性,只有了解其基础性能从而掌握它的膨胀和吸附机制,才能使它真正发挥作用。从膨胀床流体力学性能、吸附性能、吸附剂与细胞和细胞碎片之间的相互作用以及基础性能的其他方面,对近年来国内外膨胀床基础性能的研究进行了综述。     

膨胀床离子交换吸附分离纳豆激酶

对膨胀床分离纳豆激酶过程的各个阶段进行了考察。在填充床上的探索性实验表明,吸附时最佳的pH为6.0,电导率应低于6.2mS/cm。在膨胀床上样吸附阶段,考察了保持流速不变和保持床层膨胀率不变2种操作方式,结果表明采用控制膨胀率不变的方法更适合纳豆激酶这种料液的粘度和平衡缓冲液的粘度相差不大的情况;在冲洗阶段,通过考察颗粒冲洗的效率确定采用平衡缓冲液冲洗;洗脱阶段采用填充床模式洗脱。与传统方法相比,用膨胀床对纳豆激酶进行分离和纯化,操作步骤从6步减少为2步,操作时间缩短了8—10h,回收率提高了约50%。     

蛋白质的膨胀床吸附过程穿透模型分析

引　言膨胀床吸附技术是近十几年来出现的一种新型生物分离模式 .该技术集细胞碎片清除、料液浓缩和蛋白质纯化等步骤于一身 ,大大提高了目标产物收率 ,降低了纯化时间和费用 .自 1993年Streamline系列膨胀床吸附介质和装置问世以来 ,国外已有不少利用膨胀床吸附技术提取蛋白质的报道[1,2 ] .已有研究表明 ,料液特性、吸附剂粒径等对膨胀床的流体力学特性和蛋白质在膨胀床内的吸附行为有着不同程度的影响[3～ 5] .考察这些影响因素有助于加深对膨胀床层析行为的理解 ,指导膨胀床层析的优化设计 .然而 ,由于膨胀床层析过程的复杂性 ,众多因素相互作用 ,某一参数的改变往往引起操作参数的系统性变化 ,因此实验条件下考察单一参数的改变对膨胀床层析过程的影响是不现实的[5,6 ] .　　　前期研究表明 ,对不同黏度的缓冲液 ,穿透模型能够较准确的预测蛋白质的穿透行为 .因此 ,本研究在前期研究的基础上[4 ,7] ,利用穿透模型分析了膨胀床吸附过程的质量传递和流体力学特1　穿透模型该模型假设[4 ,5] :①吸附剂颗粒为球形 ,有均一的尺寸和密度 ,离子交换基团均匀地分布在颗粒内部 ;②床内径向不存在浓度梯度 ;...     

专利技术

一种煤液化油加氢稳定的方法公开(公告)号:CN 1896188公开(公告)日:2007.01.17该方法中,煤液化油经过滤后,与氢气从反应器底部进入膨胀床反应器,与加氢精制催化剂接触,反应器流出物经过气液分离、分馏,分离得到产品;从高压分离器分离出的富氢气流循环回膨胀床反应器。该方法采用膨胀床反应器,有效地缓解反应器压降上升过快的现象,并抑制反应器入口催化剂过快失活,延长开工周期,同时能脱除煤液化油中的氮,提高煤液化油质量。     

膨胀床中QMA Spherosil LS介质粒径分布

对新型的膨胀床吸附介质QMA Spherosil LS在膨胀床内的流体力学性能和粒径分布行为进行了详细的研究. 在实验过程中,通过侧壁设有多个取样口的自制膨胀床装置在线采集床层内部的固液混合物样品,考察了介质填充高度、流速及料液性质对轴向粒径分布的影响. 研究结果表明,膨胀床内QMA Spherosil LS介质的流体力学行为可用Richardson-Zaki方程很好地描述. 在膨胀床中QMA Spherosil LS介质的平均粒径沿轴向存在着明显的变化,但介质密度无明显的改变;这种粒径的轴向分布情况受床层的填充高度和流动相速度的影响. 在忽略细胞与介质相互作用的条件下,3%酵母细胞悬浮液对阴离子交换吸附剂QMA Spherosil LS的粒径分级的影响十分有限.     

颗粒床-旋流耦合分离器不同操作模式下的性能分析

通过实验分别考察了满床/空床操作模式对内置颗粒床-旋流耦合分离器分离性能的影响,获得了两种操作模式下的设备压降和捕集效率。通过改变入口粉尘浓度、入口气速和粉尘颗粒种类,发现满床操作条件下的分离效率比空床操作条件下的分离效率高,且前者压降较低。通过对出口粉尘粒径的分析,含有捕集颗粒的内置颗粒床可有效提高5 μm以下的粉尘颗粒的捕集效率,弥补了离心分离的短板。引入性能指数对不同操作模式进行定量分析,验证了满床操作条件下的耦合分离设备具有更好的综合分离性能。     

热解分离的散状料层接触传热

根据对化合物散状料层接触传导热解分离的理论，对料床的热传导进行了分析。建立了不稳定热传导过程料床的热传导计算方法，为化合物散状料层热解分离加热设备的设计提供理论依据。     

移动床亲合色谱在分离果葡糖浆工业生产中的应用

利用20柱4区连续移动床亲合色谱对果葡糖浆进行分离的中试级生产试验。理论确定了进料液流量、提余液、提取液的流量、切换时间和洗脱剂流量、回流量等操作条件,考察了SMB分离性能的情况和在具体生产中的应用情况。通过试验确定了本套连续移动床色谱分离装置分离果葡糖浆的合适操作条件,在此操作条件下,提取液中果糖的纯度可以达到95%以上,完全可以用于工业化生产结晶果糖。     

Energy Minimization in Cryogenic Packed Beds during Purification of Natural Gas with High CO2 Content

Minimization of energy consumption was explored for countercurrent switched cryogenic packed beds in which separation of CO₂ and other components of natural gas can be achieved based on differences in freezing or desublimation points. Highly pure CO₂ and methane were obtained after separation. An experimental setup for CO₂ removal from natural gas was constructed and a detailed experimental study was conducted by changing different operating parameters. Compared to other cocurrent or jacket‐cooled constant‐temperature configurations, countercurrent switched beds provided optimal separation and energy efficiencies. The effects of important process parameters like initial temperature profiles of the cryogenic bed, feed composition, and feed flow rate on energy requirement, bed saturation, bed pressure, and cycling times were investigated. The energy requirement for cryogenic packed beds was compared with the conventional cryogenic distillation process.     

山脚树矿选煤厂技术改造

论述了山脚树矿选煤厂原有洗选工艺流程,针对生产中存在的矿井原煤煤质变化大、煤泥含量高、介质消耗大等问题,提出技术改造方案。在原有工艺基础上增加原煤脱泥系统和粗煤泥回收系统,改造后洗选工艺流程为:原煤预先脱泥+无压三产品重介质旋流器+对流干扰沉降分选机(TBS)+浮选联合分选工艺。改造后,选煤厂生产方式更加灵活多变,产品适应市场能力强,设备先进可靠,高效低耗,基本解决了生产中存在的问题。选煤厂生产能力由2.6 Mt/a提高至3.0 Mt/a,提高了18.7%;原煤脱泥筛脱泥效率可提高至75%以上;TBS分选机洗选效率为69.82%,可能偏差E p为0.12;选煤厂介质消耗2.2~2.8 kg/t,比原系统降低50%左右,年节约介质粉约7500 t,节约生产成本550万元/a以上。原煤脱泥筛与TBS的配合使用基本解决了原煤煤质变化对商品煤质量的影响,提升了企业竞争力。     

Production of pure ethanol from azeotropic solution by pressure swing adsorption

Pressure swing adsorption (PSA) is attractive for final separation in the process of water removal especially for fuel ethanol production. Despite many researches on simulation and experimental works on adsorption of water on 3A zeolite in a fixed bed, none have studied a process with the actual PSA system. The purpose of this research was to study the PSA process with two adsorbers and effects of several parameters. The research also included analysis of kinetic and thermodynamic data of ethanol-water adsorption on commercial 3A zeolites in a single fixed bed. A two-level factorial design experiment was used in this research work to preliminarily screen the influence and interaction among the factors. Effects of important parameters such as initial temperature, feed concentration and feed rate were investigated. It was proven that the Langmuir isotherm could best predict the experimental results. In the PSA pilot test, the principal factors, which had effects on the performance, were feed rate, feed concentration, adsorption pressure and the cycle time. Prediction of the process efficiency in terms of ethanol recovery and enrichment was proposed in the form of regression models. The results of the study in a fixed bed adsorber could help designing a pilot-scale PSA unit. The experiments proved to be successful in terms of producing high concentration ethanol with high percentage of ethanol recovery. With further simulation work the process could be scaled up for an industrial use.     

基于双部分丢弃的模拟移动床产率提高策略

在保证产品纯度的情况下,提出一种带额外色谱柱的双部分丢弃策略以提高模拟移动床的产率。通过将工艺点选取在纯提取产品和非纯提余产品区域以增大进料流量,并将由此导致的含较多杂质的提余产品暂时丢弃。丢弃的提余产品作为循环进料通入到一个额外色谱柱中以进一步分离,部分不能达到指定纯度的额外产品被永久丢弃。在模拟移动床和额外色谱柱处分别收集到的产品组成总产品。分析了工艺点的选取、提余产品的积分纯度阈值和额外产品的积分纯度阈值对总产品性能参数的影响。研究结果表明,所提策略能够以较高的回收率利用原料,且能够显著提高分离过程的产率,其分离效果优于传统的模拟移动床工艺和部分丢弃策略。     

基于双部分丢弃的模拟移动床产率提高策略

在保证产品纯度的情况下,提出一种带额外色谱柱的双部分丢弃策略以提高模拟移动床的产率。通过将工艺点选取在纯提取产品和非纯提余产品区域以增大进料流量,并将由此导致的含较多杂质的提余产品暂时丢弃。丢弃的提余产品作为循环进料通入到一个额外色谱柱中以进一步分离,部分不能达到指定纯度的额外产品被永久丢弃。在模拟移动床和额外色谱柱处分别收集到的产品组成总产品。分析了工艺点的选取、提余产品的积分纯度阈值和额外产品的积分纯度阈值对总产品性能参数的影响。研究结果表明,所提策略能够以较高的回收率利用原料,且能够显著提高分离过程的产率,其分离效果优于传统的模拟移动床工艺和部分丢弃策略。     

TBS分选机在王家岭选煤厂的应用

阐述了TBS分选机的工作原理和技术参数。分析了两种TBS分选机入料及产物的粒度和密度组成,对比了两种TBS分选机的分选精度。结果表明:两种TBS分选机的入料粒度组成类似,0.2~1.0 mm质量分数大于60%,属主导粒级,适合采用TBS分选机分选,其精煤灰分均小于10%,尾煤灰分均高于57%,分选效果较好。当精煤灰分为9.50%时,两种TBS分选机的入料煤样均属易选煤。两种TBS分选机的Ep值分别为0.178和0.183,I值分别为0.239和0.246,分选效果基本相同,均达到较高水平,分选下限达到0.2 mm。     

Adsorbent Evaluation Based on Experimental Breakthrough Curves: Separation of p‐Xylene from C8 Isomers

The search for new adsorbents with enhanced capacity and selectivity, suitable for application on large‐scale simulated moving‐bed units for separation of p‐xylene, requires efficient, reliable, and fast adsorbent characterization methods for this specific separation. Fixed‐bed experiments were carried out under the conditions of the Parex process to evaluate a faujasite‐type zeolite as adsorbent for the separation of p‐xylene from its isomers in the proportions of the real Parex feed stream. The experimental breakthrough curves were used to evaluate the selected adsorbent in terms of nonselective and selective volumes, adsorption capacity, selectivity, and productivity, which can be applied to identify the feasible separation region for different operating conditions.     

A COMPARISON OF GAS SEPARATION PERFORMANCE BY DIFFERENT PRESSURE SWING ADSORPTION CYCLES

By simulations using an equilibrium model, a quantative comparison is made for different pressure swing adsorption (PSA) processes for gas separation. The comparison is based on the performance curve, which is defined as the relationship between product purity and product recovery at a fixed feed throughput.

For bed repressurization in the PSA cycle, the use of the light product yields superior separations compared to that using the feed mixture. For the pressure reduction step, it is found that the separation results are better when the heavy-product purge step is used, as compared to that using cocurrent depressurization. For an ultrahigh-purity light product, however, the PSA process using cocurrent depressurization is superior.

A new PSA process is suggested in which the heavy-product purge step is accomplished by using (or pressure-equalizing with) the effluent from another bed which undergoes the countercurrent blowdown step.     

A Comparison of Static Bed and Moving Bed Chromatography

Abstract

An analysis of static and moving bed perfect column chromatography is carried out for the separation of a binary mixture having constant separation factor isotherms. It is shown that the carrier requirements are identical for both methods of operation. The model does not provide information on the length of the moving bed column, but shows that the length of the static bed column can be made vanishingly small by reducing the duration of feed intervals. Furthermore, separating the feed bands only partially can - lead to a substantial reduction in the length of the static column at fixed separation rates.     

Application of an adsorption non-flow exergy function to an exergy analysis of a pressure swing adsorption cycle

Pressure swing adsorption (PSA) is a popular gas separation technology for the process industries and is commonly used for air separation, hydrogen purification, and isomer separation. In this study, we apply a second law analysis to this technology to identify sources of irreversibility in the process and, in particular, identify which steps in the PSA cycle are responsible for the major losses. Unlike previous exergy analyses, we derive and use expressions for the exergy of the adsorbed phase using adsorption thermodynamics. In this way, exergy loss (or entropy generation) within the adsorption cycle in each step is clearly identified. We illustrate the use of these exergy functions with the application of binary linear isotherm (BLI) theory to a four-step Skarstrom cycle. Major losses in the process are shown to be the exergy loss across the valve in the blowdown step, and feed compressor aftercooler losses. Feed repressurisation is shown to be more efficient than product repressurisation for the separation factor examined in this study since part of the feed gas is introduced at a low pressure. During the cycle, bed exergy loss during the feed step is significant, while there is no exergy loss in the adsorbent bed during the blowdown or purge steps. The exergy functions derived in this study can readily be applied to more complex PSA cycles and provide a basis for cycle design.