Product tri-section based crude distillation unit model for refinery production planning and refinery optimization

Accuracy of a crude distillation unit (CDU) model has a significant impact on refinery production planning. High accuracy is typically accomplished via nonlinear models which causes convergence difficulties when the entire refinery model is optimized. CDU model presented in this work is a mixed-integer linear model with a modest number of binary variables; its accuracy is on par with rigorous tray to tray CDU models. The model relies on the observation¹² that a line through the middle of the product true boiling point (TBP) curve depends on the crude feed properties and the yields of the adjacent products. Novelty of the product tri-section CDU model is that it does not require models of individual distillation towers comprising the CDU, thereby leading to a much simpler model structure. Significant reduction in the computational effort required for the optimization of nonlinear refinery models is illustrated by comparison with previous work.     

原料油虚拟组分划分方法研究

炼厂原油虚拟组分划分是原油评价过程中的一个重要环节,本文对蒙特卡罗法和实沸点蒸馏曲线法两种划分虚拟组分的方法进行了对比和分析,阐述了其适用范围和特点。进一步根据某炼油厂提供的实沸点蒸馏数据,对该厂原料油进行分析,得出该原料油的物性数据,为后面的催化裂化过程模拟奠定基础。     

基于特征选择的常减压装置模型及在计划优化中的应用

常减压装置将原油切割为不同中间产品,其作为炼油工艺的龙头装置,对炼油过程生产计划排产与效益提升至关重要。通过建立一种高精度且具有良好求解效率的常减压模型,用以求解模型关键指标实沸点（TBP）曲线,即综合考虑切割产品的实沸点（TBP）与原油TBP、流量、温度等变量影响,构建非线性方程组模型来表征输入输出间的关系;利用特征选择方法遴选相关变量（包括进料性质、相邻TBP及其二次项等）,并采用鲸鱼优化算法优化方程组系数。仿真结果表明,该多输出相互关系模型与已有文献工作相比,在兼顾求解效率基础上,常减压装置各蒸馏切割产品TBP曲线预测上有更高的精度,将此模型应用到炼厂计划优化中,与传统的悬摆切割模型对比,优化结果优于传统悬摆切割模型。     

原油蒸馏塔的模拟计算

在深入研究石油馏分虚拟组分切割方法的基础上，按照原油常压蒸馏塔的工艺原理，提出了联合使用BP法和SR法，以功能模块组合的流程模拟法求解原油常压蒸馏塔的新途径。它具有收敛性好、计算精度高等特点，为进一步实现原油常压蒸馏塔的优化和炼油厂全流程的模拟与优化奠定了基础。     

惠州炼油减压深拔措施与效果

中海油惠州炼油常减压装置处理量为1200万吨/年,为国内单套处理能力最大的常减压装置。设计加工高含酸海洋重质石油,渤海2号蓬莱19-3原油。本文通过论述惠州炼油从设计和实际生产中所采取的提高减压深拔的措施,说明在实际生产中是有效的,在提高了减压拔出率的同时,降低装置能耗,产品质量也得到一定程度的改善。     

Investigation of petroleum medium fractions and distillation residues from Brazilian crude oils by thermogravimetry

Thermogravimetry was applied to evaluate the heavy distillation residues of different Brazilian crude oils. The thermal characteristic of the samples could be studied by only one experiment. It was possible to evidence the linear correlations among the results obtained by the TG curves and by the patterned methodologies, therefore anticipating volatile and carbonaceous materials (coke) formed during their thermal cracking. The correlations herewith observed, in a short period of time, provided comparisons among the petroleum fractions.     

催化裂化催化剂铁中毒现象分析与解决方案

催化裂化作为最重要的原油二次加工手段之一,是炼厂生产轻质油品、提高经济收入的关键装置.催化装置的稳定运行直接影响炼厂的经济效益.针对某炼厂催化装置出现产品分布变差的问题,从原料性质、平衡剂性质、平衡剂评价等几方面进行了系统分析,结果表明是由催化原料铁离子含量过高引起的平衡剂重金属中毒.通过提高反应温度,降低加工量,提高...     

Optimization of crude distillation system using aspen plus: Effect of binary feed selection on grass-root design

With an objective to supplement guidelines available as general rules of thumb for the grass-root design of crude distillation unit (CDU) using binary crude mixtures, this work presents the optimization of crude distillation unit using commercial Aspen Plus software. The crude distillation unit constituted a pre-flash tower (PF), an atmospheric distillation unit (ADU) and a vacuum distillation unit (VDU). Optimization model constituted a rigorous simulation model supplemented with suitable objective functions with and without product flow rate constraints. Three different feed stocks namely Bombay crude, Araby crude and Nigeria crude were considered in this work along with various binary combinations of these crudes. The objective function considered was profit function (subjected to maximization) for cases without product flow rate constraints and raw-materials and energy cost (subjected to minimization) for cases with product flow rate constraints. Parametric study pertaining to feed selection and composition has been conducted in this work to further benefit refinery planning and scheduling. Simulation study inferred that the product flow rate constraints sensitively affect atmospheric distillation column diameter and crude feed flow rate calculations. Based on all simulation studies, a generalized inference confirms that it is difficult to judge upon the quality of the solutions obtained as far as their global optimality is concerned.     

含硫和高硫原油的加工技术

介绍了俄罗斯原油、委内瑞拉原油的一般性质及目前国内首套加工俄罗斯原油的5.5 Mt/a常减压装置的主要工艺路线和新技术特点,并针对俄罗斯原油的性质和该常减压装置的设计特点、运行中存在的问题和采取的对策及建议进行了分析讨论,如装置对加工俄罗斯原油的适应性问题、以及轻烃回收问题等,同时也对3.5 Mt/a常减压装置掺炼委内瑞拉高硫原油以及第二次加工装置的运行情况加以分析,为国内大量加工俄罗斯原油及委内瑞拉原油装置的设计提供了良好的借鉴经验。     

Heavy oil refining and transportation: effect on the feasibility of increasing domestic heavy oil production

As part of a programme to assess the feasibility of increasing domestic heavy oil production from US reservoirs, a study of the crude oil transportation system and petroleum refining industry has been initiated to determine their ability to accommodate additional domestic heavy oil. This paper summarizes refining trends and potential limitations in the production/transportation/refining network that may influence the expansion of domestic heavy oil production outside the current heavy oil producing areas. Although the number of refineries has decreased over the past decade, the remaining large refineries have been able to stabilize charge capacity and increase refinery throughput. A few refineries have been designed to economically process select heavy oils and obtain acceptable yields of products. However, refiners seek more light sweet crude oil and less sour or heavy crude to meet the requirements of clean fuels as mandated by the Clean Air Act Amendments of 1990. Transport of heavy oil poses significant problems in that there are limited heated pipelines, and transport of heavy oil to distant refineries adds to the cost of heavy oil production. Addition of significantly more heavy oil, either domestic or imported, will substantially reduce refinery efficiency and throughput affecting yields and margins. This will not change without significant investment in refinery modification to be able to process heavy oil.     

New Process for the Acid-Catalyzed Conversion of Cellulosic Biomass (AC3B) into Alkyl Levulinates and Other Esters Using a Unique One-Pot System of Reaction and Product Extraction

Abstract  

A one-pot system used for the chemical/catalytic conversion of cellulosic biomass, and the product extraction was developed. The latter phase was carried out by a distillation technique that combines a temperature-programmed heating with a vacuum level-programmed evacuation (technique of mild vacuum-assisted distillation, MVAD). No environmentally harmful solvent was used: only a high boiling paraffin (n-dodecane) was used to help distil the heavy products. The obtained liquid fractions (light and heavy fractions) could be used, after drying and removal of unused alcohol, for blending into gasoline or diesel/biodiesel. Two different conversion procedures were used: ethanolysis (direct acid-catalyzed conversion in ethanol medium) and a sequential procedure, the latter consisting of the “acid hydrolysis followed by the esterification of resulting acids with ethanol”. By using wood residues as raw material, the yields in ethyl levulinate and other by-products—with the only exception of diethyl ether (DEE), were quite similar for both procedures. The incorporation of some H-USY zeolite could significantly decrease the yield of DEE in the ethanolysis procedure. Reported results obtained with some other biomass feedstocks (particularly, switch grass) showed a good relationship between the product levulinate yield and the cellulose content of the raw material.     

Fuels by pyrolysis of waste plastics from agricultural and packaging sectors in a pilot scale reactor

The pyrolysis of waste plastics (so called chemical recycling) is one perspective way of their utilizations, but the end product properties are a key point of the industrial leading of processes. In this paper a pilot scale pyrolysis process has been investigated. Waste plastics were decomposed in a tube reactor at 520 °C, using hourly feed rate of 9.0 kg. Raw materials were selectively collected wastes from agricultural and packaging industry. For supporting the more intensive cracking of CC bonds of main polymer structure a commercial ZSM-5 catalyst was tested in concentration of 5.0%. Products were separated into gases, gasoline, light and heavy oil by distillation. Plastic wastes could be converted into gasoline and light oil with yields of 20–48% and 17–36% depending on the used parameters. The gas and liquid products had significant content of unsaturated hydrocarbons, principally olefins. In the presence of ZSM-5 catalyst the yields of lighter fractions (especially gasoline) could be considerably increased and the average molecular weight of each fraction has decreased. Gasoline had C₅–C₁₅ hydrocarbons, while light oil had C₁₂–C₂₈. The used catalyst has promoted the formation of i-butane in gases and affected the composition of both gasoline and light oil. Properties of products are advantageous for fuel-like applications, and they are able to increase the productivity of refinery. On the other hand the possibility for further utilization of products from pyrolysis basically was affected by the source and the properties of raw materials. Waste polyethylene from agricultural consisted of some elements from fertilizers (N, S, P and Ca), which could not be removed from the surfaces of raw materials by pre-treatment (e.g. washing). In that case significant concentration of N, S, P and Ca can be measured in all products, but the catalyst has decreased the concentration of impurities. Gasoline, light oil and heavy oil were nitrogen free and sulphur content was below 12 mg/kg in hydrocarbons obtained by the pyrolysis of polypropylene waste from packaging.     

灵活应用LP模型提高炼油厂设计水平

炼油厂设计水平的高低首先取决于总加工流程的选择是否优化合理。本文利用PIMS软件提供的模块化和开放性结构的建模环境,结合炼油工艺特点,根据设计需要灵活地构建了各种LP模型,用于炼油厂实际总加工流程的优化设计中。同时重点介绍了其在原油配置、重油加工路线选择和新工艺评估方面的应用成果,结果表明其对提高炼油厂的整体设计水平具有重要指导意义。     

基于EGO算法的常压塔能量优化

常减压装置能量消耗约占炼厂总用能的25%～30%,在保证产品产量与质量的条件下,优化常减压蒸馏塔操作条件,可有效降低能耗.为了避免随机优化算法对常压塔机理模型进行操作优化时,存在计算资源消耗大、效率低的问题,文中采用基于代理模型的全局优化方法优化常压塔的余热回收过程,在优化迭代过程中用Kriging代理模型来代替耗时的精确模型评估.实验表明模型调用次数相较于粒子群优化算法减少了90%,优化时间减少了85%,实现了能量优化并且保证了侧线产品之间的分离精度.     

窄馏分切割技术在清洁汽油生产工艺中的应用

采用旋转带蒸馏仪对国内某炼油厂预加氢后催化汽油进行窄馏分切割,分析各窄馏分硫和烯烃分布规律,为全馏分催化汽油分馏提供精确的切割方案。实验结果表明,通过将切割轻汽油总硫含量控制在指标要求上限,最大量将烯烃切入轻汽油中,降低重汽油烯烃含量,可减少在加氢脱硫过程中由于烯烃饱和导致的辛烷值损失。     

Studies on corrosion control of naphtha fractions in overhead condensing system using laboratory distillation device

Corrosion in the overhead condensing system of atmospheric distillation units is a common occurrence in petroleum refineries worldwide. These corrosion problems are influenced by the presence of three phases: vapours, liquid hydrocarbons and aqueous phase containing hydrochloric acid formed during distillation by decomposition of chloride salts of calcium and magnesium.Present studies highlight the corrosion control of naphtha fractions of Bombay High and Dubai crude oils in laboratory distillation device by chemical treatment using various corrosion inhibitors having different functional groups. These studies were carried out using two phase systems (aqueous-hydrocarbon) in the distillation device having facilities for monitoring the corrosion and temperatures in vapour condensing region and liquid condensate. Corrosion monitoring was carried out by potentiodynamic polarization technique and dissolved iron analysis using inductively coupled plasma atomic emission spectroscopy (ICPAES). Experimental findings indicate that Dubai naphtha fraction is more corrosive in nature when compared to Bombay High naphtha. This observation can also be explained on the basis of characterization of both crude oils and their naphtha fractions. At normally recommended dosage level as in refinery overhead systems, water soluble corrosion inhibitors are more effective than hydrocarbon soluble ones in the vapour condensing region as well as in the liquid condensate of both naphtha fractions.     

减压塔高温部位的腐蚀及耐蚀材料的选用

近年来,随着原油中酸值和硫含量的增高,常减压蒸馏装置减压塔的腐蚀情况越来越严重,高硫、高酸值原油对减压塔的腐蚀成为炼油企业亟待解决的一个重要问题。本文对减压塔高温部位的腐蚀类型和特性进行了分析,并从耐蚀材料的选择方面提出了相应的防腐对策。     

苯甲酸釜残液全部回收的工艺开发利用

Benzoic acid residue is solid waste produced from the production of benzoic acid by oxidizing toluene. Because it contained important chemical raw materials such as benzoic acid, benzyl benzoate and fluorenone, it is necessary to recover them from the residue. In this work the technique featured with high efficiency evaporation and vacuum distillation was developed to obtain total recovery and utilization of the benzoic acid residue. By controlling the operation temperature at 260°C and the pressure of 16 kPa in the rising and falling film evaporators, heavy components separated efficiently from the residue can be polymerized and the light components consisting of 63% of the residue entered into a benzoic acid vacuum distillation column. Keeping the temperature of polymerization at (280±10)°C, coumarone resin was produced after adjusting the softening point according to the market re-quirements. Vacuum distillation was operated under the following conditions: top temperature at 186°C, top pres-sure of 16 kPa, bottom temperature at 240-250°C, reflux ratio being 3︰1. Benzoic acid of 98% purity was distilled out from the column as a side stream and the bottom product was crude benzyl benzoate. By the developed tech-nique, the benzoic acid residue was splitted into three products, benzoic acid, crude benzyl benzoate and coumarone resin without any surplus waste.     

环丁砜抽提蒸馏工艺分离芳烃与非芳烃影响因素的分析

通过对环丁砜抽提蒸馏工艺影响因素——原料组成、溶剂比、溶剂温度、汽提水含量、塔压的试验分析,以降低生产成本、增加混芳收率为目标,给出了不同原料组成下适宜参数的确定方法。     

响应曲面优化粗锡真空蒸馏

采用响应曲面法优化粗锡真空蒸馏工艺,研究了蒸馏温度、保温时间和原料质量对粗锡真空蒸馏提纯效果的影响. 结果表明,蒸馏温度和保温时间对粗锡真空蒸馏影响较大,原料质量的影响较小,蒸馏温度1350~1400℃、保温时间40~60 min时可有效去除粗锡中杂质. 以97.4185%的粗锡为原料,在蒸馏温度1400℃、保温60 min的条件下,锡纯度达99.8752%,含0.012% Pb, 0.045% Sb, 0.0005% Bi和0.0005% As,Fe和Cu含量无变化,Sn直收率达99.89%.