CO+H_2两段法(MFT)合成汽油过程开发(Ⅱ)中间工厂试验

本文介绍了两段法100t油/年规模的合成油中间试验工艺流程与试验结果。重点考察了工业水煤气的净化效果,催化剂经放大制备后的活性及稳定性,测试了一、二段反应器床层温度分布,解决了一段强放热反应的稳定性操作,经1600小时运行,找到了装置的较佳操作条件,在该条件下,油收可达90～100g/Nm~3(CO+H_2),油品辛烷值(马达法)≥80。为工业放大提供了工程数据。     

反胶团法制备ZrO2超细粉末过程的放大模型

使用喷射 -搅拌混合器 ,使油水两相可以快速而且充分接触 ,从而利用反胶团法得到粒度分布均匀的ZrO2 超细粉末 .首先利用模型预测了不同转速和不同相比下两相传质的结果 ,然后用实验验证了模型的准确性 ,建议利用该模型进行放大研究     

催化剂焙烧设备的工业放大对乙苯脱氢催化剂影响的剖析

 催化剂的焙烧是催化剂制备的重要步骤，本文以乙苯脱氢制苯乙烯催化剂为研究对象，对隧道窑和连续式回转炉等常用工业设备焙烧的催化剂，与试验室马弗炉焙烧的催化剂分别进行了评价和分析。结果表明，回转炉焙烧的催化剂平均抗压碎强度和抗压碎强度方差略优于隧道窑焙烧的催化剂；回转炉焙烧的催化剂在反应活性、选择性以及比表面、孔容、平均孔径、晶粒形貌等各项特征上均达到试验室马弗炉的焙烧水平，更优于隧道窑焙烧的催化剂。催化剂的比表面、孔容、平均孔径及晶粒形貌的差别是焙烧的催化剂活性存在差异的主要原因。研究表明，从试验室小试装置到工业大规模设备存在不容忽视的催化剂焙烧过程的放大效应。     

An appraisal of the energy-size reduction relationships for mill scale-up design

In this paper, several well-known energy-size reduction relationships have been analyzed using Kapur’s similarity solution to the integro-differential equation of batch grinding. It has been shown that: (i) relationships proposed in terms of the energy actually utilized for breakage of particles, E, cannot be used to develop a practical energy-size reduction relationship as E is neither measurable nor it is found to be proportional to the measurable net energy input, E_n, (ii) the exponent of the characteristic particle size, $\overline{\mathrm{x}}$, in the relationship between E_n and $\overline{\mathrm{x}}$ is same as the exponent of particle size in the expression for the specific breakage rate function, α, which is not a function of $\overline{\mathrm{x}}$ in the case of ball mills, (iii) α values of 0, 0.5 and 1 cannot be associated with the laws of Kick, Bond and Rittinger, respectively. Based on the results of this analysis, the empirical scale-up models proposed by Bond and Morrell have been modified by replacing the exponents of 80% passing sizes by α. Further investigations have been recommended for resolution of large differences in the energy estimates obtained from these models for materials characterized by grindabilty values less than 1.0 and greater than 3.0?g/rev.     

On the modelling of multidisciplinary electrochemical systems with application on the electrochemical conversion of CO2 to formate/formic acid

This paper presents a model-based approach on the analysis of complex multidisciplinary electrochemical processes, with implementation on a reactor for the electrochemical conversion of CO₂ to formate/formic acid. The process is regarded as a system of interacting physical and electrochemical mechanisms. A process model is developed by combining individual mathematical sub-models of the mechanisms, organised at groups of compartments following the physical process structure. This approach results in a generic reconfigurable model that can be used as a part of integrated systems, and to test design modifications. The approach is demonstrated on an electrochemical cell, where CO₂ is converted to formate/formic acid. The model captures the molar transportation under electric field, the two-phase flow effects, and the key electrochemical reactions. The model is calibrated and validated against experimental data obtained from a continuous flow cell. The key parameters affecting the process performance are discussed through scale-up analysis.     

SCALE-UP OF LAYER DRYERS: A UNIFIED APPROACH

Abstract

The concept of Specific Drying Rate is introduced for analysis of experimental drying data for layer dryers and as a convenient scale-up factor. In conjunction with data obtained from a batch laboratory simulation the method is applicable to most types of continuous layer dryers. Three illustrations of the use of this approach for scale-up are presented including a continuous convection heated rotary shelf dryer, an indirectly heated paddle dryer, and an indirectly heated plate dryer with heating zones.     

INFLUENCE OF THE PARTICLE SIZE AND SUPERFICIAL GAS VELOCITY ON THE SUBLIMATION OF PURE SUBSTANCES IN FLUIDIZED BEDS OF DIFFERENT SIZES

In the present study the sublimation of large solid carbon dioxide particles inside fluidized beds of fine particles is investigated. A model which takes the surface area of the sublimable particles into account is used to describe the sublimation kinetics. Based on this model, the results of different experiments, namely single particle experiments using a precision scale, batch experiments in a laboratory-scale fluidized bed and continuous experiments in a larger circulating fluidized bed are compared. The main focus of the study is to evaluate the influences of the particle size, of the inert bed material, of the bed temperature and of the superficial gas velocity, respectively.     

钨矿强化碱煮搅拌釜的放大设计研究

以钨矿机械活化碱煮搅拌釜试验模型为对象,建立了几何相似放大的搅拌釜模型,并基于Fluent软件对模型进行模拟分析。结果表明,放大的搅拌釜在顶部两端区域易形成流动死区,不利于固液混合。优化该放大模型的搅拌釜结构和搅拌桨安装方式后能避免产生流动死区。改变搅拌釜模型的容积和搅拌桨转速,对比分析优化前后搅拌釜内流体的混合特性和搅拌功率,建立了混合特性评价体系,同等条件下,优化后的搅拌釜能缩短混合时间,提高混合效率。     

有机颜料生产工艺放大的考虑

如何将一个有机颜料制造工艺成功地从实验室放大到工厂生产?为此,首先论述工艺放大的方法论、搅拌反应器放大准则、有机颜料工艺放大的困难等一些基本因素,接着分析有机颜料反应釜放大和沉淀釜的放大,最后提出有机颜料工艺放大应该遵守的准则。     

Supercritical CO2 extraction of oilseeds: review of kinetic and equilibrium models

Mass transfer models on supercritical carbon dioxide (SC-CO2) extraction of vegetable oils are reviewed, that may facilitate the scale-up of laboratory data for industrial design purposes. Reviewed mechanisms of oil transport within the solid matrix include the desorption from the solid, the formation of a shrinking core of condensed oil in a non-adsorbing porous matrix, and diffusion in a homogenous medium. Analyzed simplificat ions of a general mass transfer model include external control of mass transfer rates, internal control of mass transfer rates, consideration of a linear driving force, and steady state approximations, among others. More complex two-stage models, and critical comparisons of some of the proposed models are also included. Trends for the external mass transfer coefficient and effective diffusivity in the solid matrix from studies on SC-CO2 extraction of oil from vegetable substrates are thoroughly discussed and contrasted with those obtained using simpler model systems. The possible effect of the axial dispersion on the rate of extraction is also discussed. Finally, the high-pressure vegetable oil-CO2 phase equilibrium is discussed in connection with its influence on the mass transfer process. Special emphasis is given to the role of the solid matrix on high-pressure phase equilibrium.