高效再生催化裂化装置多稳态分析:反应温度开/闭环控制条件对热反馈机制的影响

针对催化裂化反应-再生系统在提升管反应温度开环和闭环控制条件下的输出与输入多稳态问题,分析了烧焦罐式高效再生催化裂化反应-再生系统在两种条件下随着CO助燃剂添加量变化时的多稳态分布。在反应温度开环条件下,因再生温度与反应温度的耦合程度较低,使系统移热曲线呈单调递增,导致了系统出现3个稳态操作点。在反应温度闭环控制条件下,提升管反应器和再生器间热反馈机制发生改变,由于再生剂循环量可以作为额外的自由度对再生温度和反应温度之差进行补偿,再生器和提升管反应器的耦合程度增强,使得系统只会在助燃剂添加量极低时才会出现多个稳态点,而在基准操作条件下只有一个稳态点,规避了系统在提升管反应温度开环时的多个稳态点的问题。     

高效再生催化裂化装置多稳态分析：反应温度开/闭环控制条件对热反馈机制的影响

针对催化裂化反应-再生系统在提升管反应温度开环和闭环控制条件下的输出与输入多稳态问题,分析了烧焦罐式高效再生催化裂化反应-再生系统在两种条件下随着CO助燃剂添加量变化时的多稳态分布。在反应温度开环条件下,因再生温度与反应温度的耦合程度较低,使系统移热曲线呈单调递增,导致了系统出现3个稳态操作点。在反应温度闭环控制条件下,提升管反应器和再生器间热反馈机制发生改变,由于再生剂循环量可以作为额外的自由度对再生温度和反应温度之差进行补偿,再生器和提升管反应器的耦合程度增强,使得系统只会在助燃剂添加量极低时才会出现多个稳态点,而在基准操作条件下只有一个稳态点,规避了系统在提升管反应温度开环时的多个稳态点的问题。     

非贵金属复合氧化物CO助燃剂及其研究进展

阐述了非贵金属复合氧化物CO助燃剂的几种类型，概括了影响助燃剂活性、稳定性的几种因素，并简要指明了此类助燃剂今后的发展方向。     

新型5号CO助燃剂性能研究及其应用

新型5号CO助燃剂由于改进了载体制备及金属加入工艺,使微球状助燃剂的物理性质可与裂化催化剂相匹配,具有耐磨性能好、筛分组成集中、细粉少、堆密度大等优点。使用时的流化性能好,损耗低,密相床停留时间长。与第一代工业用助燃剂相比,铂用量节省30%～56%,金属保留率由130%提高到260%,充分发挥了活性组分铂催化氧化CO的作用。     

催化裂化再生器中铂助燃剂催化活性的测定（I）：在新助燃剂上CO氧化的…

研究了催化裂化再生条件下铂燃剂上ＣＯ氧化反应动力学。在排除了反应管及稀释剂的催化氧化作用后，测定了铂含量１０＾－６ｇ／ｇ的国产新助燃剂上的反应动力学数据，得出了在氧过量时一氧化碳和氧的反应级数分别为１和０；５。．给出了６６０℃下的反应速度常数值及其置信区间。     

CO助燃剂的新发展

本文陈述了CO助燃剂近年来的发展概况,并介绍了国内近年新开发的铂剂及稀土复合氧化物助燃剂在实际生产中的应用情况。     

利用催化裂化烟气中CO生产碳酸二甲酯

提出用变压吸附法提纯催化裂化再生烟气或炼钢高炉尾气中的CO,通过甲醇液相氧化羰基化法生产DMC的工艺路线。这对提高企业经济效益,减轻环境污染,促进资源的合理利用,有重大而深远的意义。     

化学反应系统的多稳态分析

描述化学反应系统的方程组具有强非线性,而对于非线性问题一般情况下有多个解,如何求解出这些解是一个研究热点。本文针对这一问题提出了一种扩展的同伦延拓法,并以一个理想反应器体系为例,显示出化学反应器具有的多稳态特性。为了深入了解反应系统的本质特性,文中将稳态解的计算结果转化为参数平面上的空间图像,以进一步分析在单参数连续变化下体系的多稳态解的分布情况。     

CC-20DF催化剂在灵活多效催化裂化装置上的应用

在双提升管催化裂化装置(FDFCC)上,使用长岭催化剂厂生产的CC-20DF催化剂,液态烃收率及烃中的丙烯含量增加,当CC-20DF催化剂占总藏量40%时液态烃收率达到13.5%,丙烯收率达到4.52%(收率均相对于总进料,以下同).     

多参数协同优化方法在催化裂化装置中的应用

提出一种催化裂化装置多参数协同优化方法。在选取催化裂化装置参数的基础上,构建多参数协同优化模型,依托催化裂化装置多参数优化求解策略的分析,实现催化裂化装置多参数协同优化。实验结果表明,催化裂化装置多参数协同优化方法相比于单参数优化方法,对催化裂化装置的石油产出具有较高的产出能力。     

The determination of possibility of multiple steady states for complex catalytic reactions in an isothermal CSTR

A class of complex reaction networks with deficiency from two to six, involving isothermal catalytic reactions in a continuous flow stirred tank reactor (CSTR), is determined to have the capacity to admit multiple positive steady states by implementation of the combination of the Deficiency One Algorithm and the Subnetwork Corollary. A set of rate constants and two corresponding positive steady states, one stable and the other one unstable, are constructed for four examples.     

Multiple steady states in two-phase reactors under boiling conditions

In this paper, we analyze the nonlinear behavior of two-phase reactors under boiling conditions. First we focus on a simple nth-order reaction of the form A→B, which allows a rigorous analytical treatment. Three necessary conditions for the existence of multiple steady states have been identified: the reactant A has to be the light-boiling component, the difference in boiling point temperatures between the reactant A and the product B has to be sufficiently large, and the order of the reaction has to be less than some physical parameter α. This parameter α can be interpreted as a measure for the phase-equilibrium-driven self-inhibition of the reaction mechanism. Thus, we have found an elegant explanation for the occurrence of multiplicities. Analytical and therefore general quantitative criteria identifying the regions of multiplicity for the model system are presented. Practical relevance of our results is demonstrated by means of two examples, the Monsanto process for the production of acetic acid and the ethylene glycol reactive distillation system.     

一氧化碳偶联反应器分岔行为

The bifurcation behavior of the CO coupling reactor was examined based on the one-dimensional pseudohomogeneous axial dispersion dynamic model. The method of finite difference was used for solving the boundary value problem; the continuation technique and the direct method were applied to determine the bifurcation diagram.The effects of dimensionless adiabatic temperature rise, Damkoehler number, activation energy, heat transfer coefficient and feed ratio on the bifurcation behavior were investigated. It was shown that there existed static bifurcation and the oscillations did not occur in the reactor. The result also revealed that the reactor exhibited at most 1-3-1 multiplilicity patterns within the range of practical possible parameters and the measures, such as weakening the axial dispersion of reactor, enhancing heat transfer, decreasing the concentration of ethyl nitrite, were efficient for avoiding the possible risk of multiple steady states.     

Temperature response to reactant concentration perturbations in a packed‐bed reactor

Unsteady‐state operations are known to enhance the performance of some packed‐bed reactor systems. However, negative effects of this type of operation should not be neglected. Temperature excursions developed during transients may accelerate some deactivation mechanisms, reducing catalyst lifetime and selectivity. Temperature response to perturbations in reactant concentration was studied for CO oxidation over Pt/Al₂O₃ in a packed‐bed reactor. Experiments were conducted in the CO concentration range for which multiple steady states are observed. Temperature and concentration profiles in the packed‐bed reactor at steady state were found to depend on the dynamic history of the reactor prior to the steady‐state condition.     

The effect of non‐ideal mixing on the number of steady states and dynamic behaviour for autocatalytical reactions in a CSTR

In this paper, we analyze the concentration multiplicity and dynamic behavior for an autocatalytical reaction, A + R → (n + 1)R + products with an overall rate expression given by – γ_a= kc_a^pc_r^r(p > 0 and r > 0) in a imperfectly mixed (Cholette's model) CSTR. We proved that non‐ideal mixing had an effect on the number of steady states and dynamic behavior for the reaction orders r > 1 and r = 1. However, the above‐mentioned effect does not happen for the reaction order r < 1. Furthermore, a simulated example was used to demonstrate our results.     

Effectiveness factor approximations for multiple steady states in porous catalysts

The effectiveness factor is formally determined by solving a two-point boundary value problem, often numerically. To enhance the computational efficiency in simulations of large-scale reactor systems with porous catalysts, a simple approximation formula for the effectiveness factor is often used. For some reaction rate functions, however, the effectiveness factor as a function of Thiele modulus can show multiple values or sharp changes for a small change in the modulus. In this case, single-valued approximations of the effectiveness factor may give rise to large errors. Based on the two well-known asymptotes of the effectiveness factor for small and large Thiele moduli, we proposed equations for the approximation of the effectiveness factor for up to three multiple steady states and two catalyst geometries of an infinite slab and a sphere. The proposed equations were demonstrated to be useful in estimating the effectiveness factor, particularly for the stable steady states, and also in quickly estimating the Thiele modulus range where multiple effectiveness factors should be searched.     

稀土助剂RE-Ⅱ的工业应用

将多功能稀土助剂RE-Ⅱ在中油股份克拉玛依石化分公司的两套FCC装置上进行了工业应用。结果表明，与使用常规铂CO助燃剂比，该助剂具有更好的助燃效果及稳定性，且能显著降低再生烟气中氮氧化物(NOx)的浓度，能够与主催化剂很好的匹配，提高总有价值产品收率。     

催化裂化装置再生器主风裕量的动态分析

以某催化裂化装置为基础,建立反应-再生系统的动态机理数学模型。从生产操作和闭环控制的角度,用动态优化的方法对再生器的主风裕量进行了计算,指出过程动态特性对主风设计裕量的选取有着很大影响。在考虑工艺和设备条件变化留出的稳态裕量之外,需要留出一定的动态裕量以满足过程操作和控制的要求,其大小与控制系统设计有关。系统对控制器性能的要求愈高,所需要的主风裕量应愈大。故在进行工艺设计时需要对系统的控制性能和主风设计裕量进行综合考虑,使设计结果既能满足工艺要求,又能实现良好的自动控制。     

Strategies for Starting Up Azeotropic Distillation Columns with Multiple Steady States

The operability of azeotropic distillation columns with multiplicity is analysed during start‐up by dynamic simulation. Different steady states can be reached by applying different start‐up configurations and/or policies. The well‐known benzene‐heptane‐acetone (BHA) system is studied. The process by which the column reaches these steady states can be seen through the examination of profile evolutions corresponding to the given start‐up policies. Indeed, a clear partition of the start‐up policies space yielding different solutions is achieved. Some properties of this space are explained and start‐up critical values can be identified. Finally, some guidelines for start‐up supervision are outlined for the study case.