丁苯嵌段共聚物的加氢及性能研究

采用镍系催化剂用于丁苯嵌段共聚物 (SBS)加氢反应 ,考察了反应温度、压力、催化剂用量等对加氢反应的影响 ,得到较佳的加氢反应工艺条件 :加氢反应温度 5 5～ 6 5℃ ,反应压力大于 2 .5MPa,催化剂用量为 0 .0 5～ 0 .1g/10 0 g聚合物。该催化剂选择性好 ,可使聚合物中的共轭二烯烃段有效加氢 ,其加氢度 >98% ,苯环加氢度 <5 %。同时对加氢前后聚合物微观结构、物性变化及老化性能进行了研究。     

裂解汽油一段选择性加氢的工艺条件研究

采用高压搅拌釜式反应器,在消除催化剂内外扩散影响的基础上,以环戊二烯、苯乙烯和1-己烯与溶剂正庚烷组成的混合物为模型化合物,对裂解汽油一段选择性加氢的操作条件进行了研究.发现当反应温度和压力升高时,各个组分的转化率都随之增高,但是双烯的加氢选择性变差.当单烯和双烯组分共存时,环戊二烯和苯乙烯优先进行加氢反应,当双烯浓度降至一定程度时,1-己烯才进行加氢.此外还采用固定床考察了温度、压力和氢油比对裂解汽油加氢的影响.结果表明,较合适的反应条件为313 K,2.5～3.0 MPa和氢油比25.     

加氢操作反应机理及装置功能特性

通过反应物传质模型论述了加氢反应装置的反应机理;分析了反应阻力与其影响因素之间的关系;介绍了搅拌槽型加氢反应装置的结构形式和操作过程;以混合型加氢反应器和自吸式搅拌槽为例,论述了加氢反应器的性能特征、主要功能和技术管理要点。     

催化剂失活条件下的碳二加氢反应器模拟与优化

乙炔加氢反应催化剂的活性与选择性随着使用时间变化而变化,操作参数需要相应的改变从而使得收益最大化。因此本文采集工业数据,通过遗传算法拟合了反应动力学模型和失活反应模型的参数;比较了国内最普遍使用的两种催化剂的选择性和活性保持方面的性能;针对串联使用的两台装填不同催化剂的反应器组合,以运行周期、乙烯产率最优为评价标准,提出了反应器3种组合优化、负荷分配优化等优化策略。将优化策略应用于实际工业装置的分析与运行,乙烯产率和总选择性提高,效果得到验证。     

环戊二烯及双环戊二烯对裂解汽油全馏分加氢装置运行的影响

介绍了裂解汽油全馏分加氢过程中发生的环戊二烯热二聚及双环戊二烯热分解反应。该转化反应导致了二段加氢反应器双烯值高于一段出料的双烯值,并缩短了二段加氢反应催化剂的运行周期,提出了降低影响的措施。     

长链正构烯烃中双烯选择加氢催化剂的研究

本文报道了以非贵企属添加助剂为活性组分的高选择性双烯加氢催化剂。当用于轻蜡脱氢油中双烯选择加氢时,其选择性和稳定性很好。在较温和的反应条件下(压力0.7MPa,温夏200℃,氢油比0.005,液时空速5),产品中的双烯含量〈0.02％,在连续反应700多小时后,催化剂的选择性基本保持不变。此外,还考察了催化剂的扩试性能,表明与实验室结果重复。     

裂解汽油中混合烯烃选择性加氢反应动力学

采用高压搅拌釜式反应器,在消除催化剂外扩散影响的基础上,对裂解汽油选择性加氢反应动力学进行了研究。以反应组分环戊二烯、苯乙烯、1-己烯与溶剂正庚烷的混合物为模型化合物,考察了反应温度和压力的影响。结果表明,环戊二烯、苯乙烯、1-己烯和环戊烯在催化剂表面为竞争加氢,双烯的反应速率远大于单烯。采用Langmuir-Hinshelwood反应机理,导出了反应动力学模型,并采用非线性最小二乘法对动力学模型参数进行估值。实验结果验证了动力学模型的合理性。     

新型裂解汽油一段加氢催化剂的性能评价

对新研制的裂解汽油一段选择性加氢催化剂的性能进行了研究，考察了入口温度、反应压力、氢油比、空速、原料水含量及胶质含量等因素对双烯加氢率及加氢选择性的影响。结果表明，在适宜的工艺条件下，该种催化剂双烯加氢活性和选择性与现行工业用一段加氢催化剂性能相当，抗胶质性能较好，具有良好的工业应用前景。     

裂解汽油一段加氢绝热反应器的开发

通过对裂解汽油一段加氢8601催化剂及 PGC 催化剂在绝热积分床反应器中的反应特性研究,考察了在工业原料条件下,入口双烯值 C_o、入口温度 T_o 以及液时空速 S_v 对双烯加氢率及反应温升的影响。并利用正交实验设计的方法,回归得到一组经验数学模型。通过误差分析以及将模型的计算值与工业实际生产数据的比较,其双烯加氢率误差小于4%,反应温升误差小于10℃,证明了该模型可以运用于入口双烯值4～12,入口温度30℃～50℃,液时空速6～12h,操作压力3.92MPa 以及氢油比0.2(分子比)的条件下,预示该催化剂在工业反应器中的反应结果,同时也可提供裂解汽油一段加氢绝热反应器的设计参考。     

催化加氢合成苯并三氮唑类紫外吸收剂

在催化剂作用和氢气气氛下,经过偶氮化合物加氢还原、脱水环化和加氢脱氧合成苯并三氮唑类紫外吸收剂。相比于化学还原合成方法,催化加氢路线具有原子经济性高、环境友好的特点。通过研究催化加氢合成苯并三氮唑类紫外吸收剂主反应和副反应发生的过程,修改了反应机理,增加了共轭碳碳双键加氢的副反应路线。考察了碱性助剂有效提高目标产物选择性的作用机制。提出了活性氢物种对氮氧化物的还原是引起其开环生成两分子芳胺副产物的主要诱因,三氮唑环与相邻苯环形成的共轭双烯结构的过度加氢生成了四氢副产物。     

反应级数对理想反应器组合方式效率的研究

对于不同级数的不可逆反应,研究了其在全混流反应器(CSTR)与平推流反应器(PFR)不同组合方式中的最终转化率。对两种理想流动反应器的不同组合方式,如CSTR+PFR串联、PFR+CSTR串联及CSTR与PFR并联,反应的最终转化率随反应级数的不同而变化。当反应级数为负值时,CSTR与PFR并联组合方式的最终转化率最高;当反应级数为0~1之间的数值时,CSTR+PFR串联组合方式的最终转化率最高;而当反应级数大于1时,PFR+CSTR串联组合方式的最终转化率最高;当反应级数为0时,三种组合方式具有相同的最终转化率;但当反应为一级不可逆反应时,两种反应器串联时的最终转化率相同,并高于两种反应器并联时的最终转化率。     

Differentiation criteria study for continuous stirred tank reactor and plug flow reactor

All reactors in reality are not ideal plug flow reactor (PFR) or ideal continuous stirred tank reactor (CSTR). They are difficult to differentiate. This study was to investigate the reactor analysis of PFR and CSTR through tracer response curves, residence time distributions (RTD) and several hydraulic performance indexes. We set up the differentiated value of each index. The tracer response curve showed that our lab-scale CSTR was close to ideal CSTR and got 99.9% recovery. In the RTD curves, the results could significantly recognize the PFR nature of high rate pond (HRP). With hydraulic performance indexes study, every selected index demonstrated that the studied HRP was closer to PFR than the studied CSTR. Based on the lab-scale study results, this study established the cutting point between the PFR and CSTR in each index; we were looking through the different types of reactors in literature and we confirmed the criteria with all literature reactors with the “graphic method”. The method helped us to establish those important values to help us to differentiate the reactor types in practice and to understand the designs better.     

Bromate Ion Formation: Impact of Ozone Contactor Hydraulics And Operating Conditions

This paper presents a simplified kinetic reaction rate model which enables the evaluation of various contactor hydraulics on bromate ion formation. Two extreme reactor types are presented: completely stirred tank (CSTR) and plug flow reactors (PFR). The kinetic modeling has been based on reactions and rate constants for molecular ozone mechanisms. At this stage, the work presented does not take into account the formation and reaction of hydroxyl radicals in the reaction pathway. However, for further in-depth modeling consideration, it is questionable that no hydroxyl radicals are formed. Similar bromate ion levels were predicted with a PFR and a CSTR for similar operating conditions in the case of predominantly molecular ozone reactions. However in most cases, a CSTR will require a much higher Cτ (product of the residual ozone concentration and the hydraulic residence time) than a plug flow reactor in order to achieve similar treated water quality goals.     

氯苯反应器数学模型的研究

通过对氯苯反应器中气、液两相传质及反应特征的分析,提出了按照CSTR串联PFR模型设计氯苯反应器的观点。其中CSTR为主要反应区域,约占全塔反应体积的80%。进一步的计算表明,用模型预测的反应器出口转化率与反应器的实际转化率一致。     

Steady state multiplicity behavior of an isothermal axial dispersion fixed-bed reactor with nonuniformly active catalyst

An isothermal, heterogeneous fixed-bed reactor packed with nonuniformly active catalyst pellets where a biomolecular Langmuir-Hinshelwood reaction occurs, is studied using an axial dispersion model. A catalyst activity distribution given by a Dirac delta function, where the active catalyst is deposited at a specific location within the pellet, is considered. This includes the common case of externally coated pellets with external mass transfer resistance. The steady state multiplicity behavior of this reactor, and its limiting cases: CSTR, PFR and pseudohomogeneous axial dispersion, are examined in detail. The nonlinearity of the reaction kinetics provides two sources of multiplicity, through the heterogeneous nature of the reactor and the presence of axial dispersion in the fluid phase. Their roles in determining reactor multiplicity behavior are fully explored. It is shown that this system can admit at most nine steady state solutions. The limiting behavior of the heterogeneous axial dispersion model as Pe → 0 or ∞ is not represented fully by the CSTR or PFR models because of ignition phenomenon. Finally, the effects of mixing on reactor conversion are discussed.     

Continuously Conducted Selective Hydrogenation of Benzene to Cyclohexene in a Four‐Phase System

Currently, the production of nylon 6 and nylon 6.6 is based on the complete hydrogenation of benzene to cyclohexane over nickel or platinum catalysts and its subsequent oxidation at very low conversions to a mixture of cyclohexanol/cyclohexanone. This mixture is further reacted to ?‐caprolactam or adipic acid. Alternatively, the reaction can be carried out by selective hydrogenation of benzene to cyclohexene and subsequent hydration with acidic catalysts to cyclohexanol. A laboratory method for the selective hydrogenation of benzene in a continuous stirred‐tank reactor (CSTR) using a gas/liquid/liquid/solid system is presented.     

Kontinuierliche Reaktionsführung der selektiven Hydrierung von Benzol zu Cyclohexen in einem Vier‐Phasensystem

Currently, the production of nylon 6 and nylon 6.6 is based on the complete hydrogenation of benzene to cyclohexane over nickel or platinum catalysts and its subsequent oxidation at very low conversions to a mixture of cyclohexanol/cyclohexanone. This mixture is further reacted to ?‐caprolactam or adipic acid. Alternatively, the reaction can be carried out by selective hydrogenation of benzene to cyclohexene and the subsequent hydration with acidic catalysts to cyclohexanol. A laboratory method for the selective hydrogenation of benzene in a continuous stirred‐tank reactor (CSTR) using a gas/liquid/liquid/solid (g/l/l/s) system is presented.     

A systematic generation of reactor designs: I. Isothermal conditions

A new method is proposed for systematic generation of conceptual design of reactor networks. Given feed compositions and a kinetic model, the objective is to find the optimal mixing structure and feed distribution. The method aims at finding the optimal sequence and sizes of ideal reactors and the optimal addition of extra feed streams along the reactor path. The total reaction time is calculated so as to maximize the space time yield subject to a minimum yield of the key product component. The method does not have any limitations with respect to the number of components or reactions. A new model formulation is proposed that comprises both CSTR and PFR model equations and the design problem is formulated as an optimal control problem. In this paper, only isothermal conditions are considered.     

反应器网络综合分区法中的简捷计算

针对定态、等温、恒容、单股进料的复杂反应过程,首先将反应器网络综合可得区分区法由浓度空间拓展至瞬时选择性-关键反应物未转化率（S-x）空间,然后根据分区法中两条重要曲线的特性（选择性最大曲线dS/dx=0,单程收率最大曲线S=0）建立了以废料最少为目标的反应器网络基本组成单元（PFR和CSTR）的数学模型,并以Van de Vusse反应模式为例将其应用于由分区法确定的最优反应器网络结构的模拟计算.计算结果与文献值一致,表明本文所用方法具有一定的简捷性和实用性.     

连续微反应加氢技术在有机合成中的研究进展

加氢反应是有机合成中很常见的一种反应类型,采用常规的间歇加氢釜具有反应效率低、操作烦琐和安全性差等问题。而连续加氢微反应器进行非均相催化加氢反应能提供更高的传质性能,催化剂的回收利用与产物的纯化也更为方便,能极大地提高生产效率,减少贵金属催化剂的损失。因为这些优点,连续微反应加氢技术得到了越来越多的关注。本文阐述了连续微反应加氢技术中常用的微反应器与固体金属催化剂类型,以及不同官能团非均相高效催化加氢的研究进展,在此基础,对该技术在精细化工领域的应用进行了展望。连续微反应加氢技术使得加氢过程可以在更安全、更高效、更环保的条件下完成,具有很高的工业应用价值,是未来化学化工领域重点发展的方向之一。