Mathematical Modeling and Optimization of Iron Ore Sinter Properties

The quality of iron ore sinter is a critical factor determining the productivity of blast furnaces for iron-making. CSIRO has therefore been developing capabilities for predicting sinter characteristics, which enables sinter quality to be improved/optimized and preliminary assessments to be made of the suitability of specific ores or ore blends for sinter production. An extensive database of pilot-scale sintering experimental results has been used to create mathematical models for predicting different sinter properties. In addition to size distribution and other physical and chemical characteristics usually used for sinter quality prediction, the mineralogical and textural characteristics of iron ores intended for sintering have also been taken into account. This approach has been quite successful, the variation of sinter reduction degradation index (RDI) that is accounted for by explanatory variables (R-Sq) being 87%, for example. Optimization criteria have been developed that take into account several sinter characteristics simultaneously, and optimization of different iron ore blends to produce target sinter characteristics has been carried out. Modeling results and their preliminary validation are discussed.     

Mathematical Modeling and Genetic Algorithm Optimization of Reactive Absorption of H2S

A rate‐based mathematical model was developed for the reactive absorption of H₂S in NaOH, with NaOCl or H₂O₂ as the chemical oxidant solutions in a packed column. A modified mass transfer coefficient in the gas phase was obtained by genetic algorithm and implemented in the model to correct the assumption of instantaneous reactions. The effects of different operating variables including the inlet H₂S concentration, inlet gas mass flux, initial NaOH, concentrations of the chemical oxidants in the scrubbing solutions, and liquid‐to‐gas ratio on the H₂S removal efficiency were studied. A genetic algorithm was employed to optimize the operating variables in order to obtain maximum removal efficiency of H₂S. The model results were in good agreement with the experimental data.     

浅谈加氢催化剂器外预硫化技术发展现状

文章浅析了20世纪80年代至今,法国EURECAT公司、美国CRITERION公司、德国TRICAT公司以及国内石油化工科学研究院、抚顺石油化工研究院等在加氢催化剂器外预硫化技术领域的发展状况,为石油化工研究院DSO项目研发的加氢催化剂硫化方法的改进提供参考。     

Hydrotreatment of Cracked Light Gas Oil

Since worldwide conversion processes are used to upgrade heavy oil to distillates, the hydrotreatment of light gas oil (LGO) as a downstream process has been used more extensively. This fraction (LGO) is produced from thermal or catalytic cracking or hydrocracking processes. It contains high amounts of unsaturates, nitrogen, and sulfur compounds which cause instability while in storage due to gum formation. The use of LGO as a fuel oil for diesel engines plugs the filter and produces sulfur and nitrogen emissions. These sulfur and nitrogen compounds arise from the cracking of heavy cuts and are aromatic-type molecules which are difficult to hydrogenate. This cut also possesses a low cetane index (CI) which must be increased (by aromatic hydrogenation) because of its poor motor performance. Color and color stability are associated with a high bromine number (BN, unsaturated content), nitrogen, and aromatic content. In order to improve these properties, a deep hydrogenation is sometimes required.     

重质馏分油性质及其加氢处理

介绍了重馏分油性质及其作为催化裂化和加氢裂化原料的要求,指出劣质重馏分油应预先加氢处理,脱除硫、氮、残炭和重金属并使多环芳烃饱和,以提高流化催化裂化（FCC）轻油产率,改善产品质量,减轻环境污染;作为加氢裂化原料,则可以充分发挥加氢裂化催化剂功能,延长催化剂使用周期。     

Hydrotreatment of Cracked Light Gas Oil

Since worldwide conversion processes are used to upgrade heavy oil to distillates, the hydrotreatment of light gas oil (LGO) as a downstream process has been used more extensively. This fraction (LGO) is produced from thermal or catalytic cracking or hydrocracking processes. It contains high amounts of unsaturates, nitrogen, and sulfur compounds which cause instability while in storage due to gum formation. The use of LGO as a fuel oil for diesel engines plugs the filter and produces sulfur and nitrogen emissions. These sulfur and nitrogen compounds arise from the cracking of heavy cuts and are aromatic-type molecules which are difficult to hydrogenate. This cut also possesses a low cetane index (CI) which must be increased (by aromatic hydrogenation) because of its poor motor performance. Color and color stability are associated with a high bromine number (BN, unsaturated content), nitrogen, and aromatic content. In order to improve these properties, a deep hydrogenation is sometimes required.     

稠油加氢处理试验研究

面对世界范围的能源短缺,寻求可利用资源和常规较难加工的资源是必由之路,因此稠油的开采加工越来越受到关注。加氢处理可以显著提高石油资源利用率,同时过程清洁环保,是今后炼油工艺的发展方向。以拓展渣油固定床加氢装置原料范围为目的,对常规不走加氢路线的一种劣质稠油进行了加氢试验研究。     

Foam-Mat Freeze Drying of Egg White and Mathematical Modeling Part I Optimization of Egg White Foam Stability

Egg white (albumen) is a rich source of protein and is widely used in confectionary industry for its wonderful foaming ability. Foam-mat freeze drying is one of the promising methods of drying, which tries to utilize the advantages of both freeze drying and foam-mat drying to produce better quality egg white powder. Preliminary experiments showed that the stability of foams made with egg white alone is not adequate for foam-mat freeze drying. Experiments were thus conducted using different stabilizers (methyl cellulose, propylene glycol alginate, and xanthan gum) to optimize foam stability. Bubble size distribution was determined using microscopy to understand foam structure. This article will discuss the effect of stabilizers on the stability of egg white foam and possible mechanisms involved. The results showed that xanthan gum at 0.125% provided sufficient stability for freeze drying.     

Foam-Mat Freeze Drying of Egg White and Mathematical Modeling Part I Optimization of Egg White Foam Stability

Egg white (albumen) is a rich source of protein and is widely used in confectionary industry for its wonderful foaming ability. Foam-mat freeze drying is one of the promising methods of drying, which tries to utilize the advantages of both freeze drying and foam-mat drying to produce better quality egg white powder. Preliminary experiments showed that the stability of foams made with egg white alone is not adequate for foam-mat freeze drying. Experiments were thus conducted using different stabilizers (methyl cellulose, propylene glycol alginate, and xanthan gum) to optimize foam stability. Bubble size distribution was determined using microscopy to understand foam structure. This article will discuss the effect of stabilizers on the stability of egg white foam and possible mechanisms involved. The results showed that xanthan gum at 0.125% provided sufficient stability for freeze drying.     

生物膜数学建模的发展

生物膜普遍存在于自然与工业环境中。探讨生物膜的结构对研究生物膜的形成机理至关重要。而数学模型是模拟生物膜结构的一种有效工具。文章重点阐述了一维连续介质模型、扩散限制凝聚(DLA)模型、离散-连续介质耦合模型、多项流体模型四类模型在生物质生长和扩散、基质传递和耗散的生物膜结构中的研究进展与实验中的新发现。     

Mathematical Modeling of Continuous Butadiene Polymerization

Butadiene polymerization on a cobalt-containing catalyst in a continuous reactor is modeled. Expressions for the molecular-weight characteristics of polymers are derived. The contributions from chain transfer and polyaddition reactions to the breadth of the molecular-weight distribution of the polymer are analyzed.     

催化裂化汽油加氢处理技术进展

本文从降低汽油硫含量、烯烃含量以及提高汽油辛烷值三个方面介绍了催化裂化汽油加氢处理技术的进展，并对技术的发展提出建议。     

Mathematical Modeling of Agitated Thin-Film Dryer

Agitated thin-film dryers (ATFDs) are used to produce dry free-flowing powder from slurry/solution-type feed and widely implemented in pharmaceutical, chemical, and food industries. The feed passes through the ATFD in several forms such as solution/slurry and successively becomes paste, wet powder, and dry powder. The flow of feed in the ATFD undergoes a helical path (combination of rotational velocity imparted by the agitator/blade and axial velocity of feed) while flowing through the annular part of the dryer. The ATFD is described stage-wise and the parameters such as physical properties, scraped surface heat transfer coefficient, and evaporation rate (drying rate) are derived using stepwise model equations. The penetration theory is modeled to obtain the scraped-side heat transfer coefficient. The model equations were solved using MATLAB 7 (MathWorks Inc., Natick, MA) and the simulated drying rate was consequently validated with the experimental values.     

Mathematical Modeling of Yarn Winding Tension

Fibre Chemistry - The problem of mathematical modeling of synthetic yarn tension in the transporting area of the take-up and winding device is investigated. Based on balance of moving masses, a...     

渣油加氢催化剂的研究和应用

渣油加氢处理技术是近年发展最快的技术领域。渣油加氢处理催化剂是此技术的关键。多种固定床渣油加氢处理催化剂在国外已进行了开发和工业应用。我国也开发了多种固定床渣油加氢处理催化剂，实践表明这种催化剂具有良好的活性和稳定性，产品质量良好，收率高，可为RFCC提供优质的原料。悬浮床渣油加氢处理催化剂也在开发之中，中试试验取得了良好的结果。     

Mathematical Modeling and Optimization of Combined Steam and Dry Reforming of Methane Process in Catalytic Fluidized Bed Membrane Reactor

Mathematical modeling of the methane-combined reforming process (steam methane reforming–dry reforming methane) was performed in a fluidized bed membrane reactor. The model characterizes multiple phases and regions considering low-density phase, high-density phase, membrane, and free board regions that allow study of reactor performance. It is demonstrated that the combined effect of membrane and reaction coupling provides opportunities to overcome equilibrium limits and helps to achieve higher conversion. Additionally, the influence of key parameters on reactor performance including reactor temperature, reactor pressure, steam to methane feed ratio (S/C), and carbon dioxide to methane feed ratio (CO₂/C) were investigated in the multi-objective genetic algorithm to find the optimal operating conditions. Finally, the process of steam reforming was simulated in selected optimal conditions and the results are compared to those of the combined reforming process. Comparison reveals the superiority of the combined reforming process in terms of methane conversion, catalyst activity, and outlet H₂/CO ratio in the syngas product in being close to unity.     

加氢催化剂器外预硫化技术现状

概述了加氢催化剂的预硫化方法的基本原理,介绍了采用不同硫化剂的预硫化技术现状及国内器外预硫化技术的研究现状。指出器外预硫化将不断取代器内预硫化,表明未来开发预硫化催化剂的研究方向和重点。     

数学建模在化工专业中的应用

数学建模在化学工程专业课程中广泛存在,并在实际化工生产过程中普遍应用.近年来,数学建模竞赛由于其题目考察学生能力的多样性与综合性,已得到越来越多高校的重视.数学建模竞赛通常会涉及化工专业相关的知识,要求化工专业学生将所学习的理论知识进行实际运用,甚至要辅以计算机编程知识对题目进行求解.这对化工专业的学生是一项挑战,能培养学生的综合能力,达到全方位培养人才的目标.