Rigorous optimization of heat-integrated and Petlyuk column distillation configurations based on feed conditions

The steady-state design and rigorous simulation of conventional distillation configurations and several energy-integrated configurations has been studied for ternary mixture separation. The studied configurations are optimized rigorously based on total annual cost as the economic objective function. The energy-integrated distillation configurations are compared with conventional configurations to find the maximum achievable total annual cost savings. Changing feed conditions is considered as one of the optimization variables by investigating different states of feed conditions; feed at 15.5°C temperature, liquid at bubble point and vapor at dew point. The investigated configurations are conventional direct and indirect separation sequence, heat-integrated direct sequences, Petlyuk column, heat-integrated sloppy sequence, and double heat-integrated sloppy sequence. Optimization results indicate that saving in energy and total annual cost of the configurations is affected by the states of the feed conditions.     

Process analysis and optimization of biodiesel production from soybean oil

The overall goal of this work is to design and optimize a biodiesel production process from soybean oil. To achieve this goal, several inter-connected activities were undertaken. First, an initial flowsheet for the process was synthesized. The performance of this flowsheet along with the key design and operating criteria were identified by conducting computer-aided simulation using ASPEN Plus. Various scenarios were simulated to provide sufficient understanding and insights and to select a base-case flowsheet. Next, mass and energy integration studies were performed to reduce the consumption of material and energy utilities, improve environmental impact, and enhance profitability. Capital cost estimation was carried out using the ICARUS Process Evaluator computer-aided tool linked to the results of the ASPEN Plus simulation. The operating cost of the process was estimated using the key information on process operation such as raw materials, utilities, and labor. A profitability analysis was carried out by examining the return on investment and the payback period. It was found that the cost of soybean oil is the largest contributor to the production cost. A sensitivity analysis was carried out to determine the effect of soybean oil prices on the process profitability.     

Erosion-corrosion of a stainless steel distillation column in food industry

Unusual extended corrosion phenomena were detected in a distillation column made in AISI type 316 stainless steel (UNS S31600) of a plant for natural pectins extraction from citrus. The column was the first of a series of two distillation columns representing the unit core. Corrosion problems were observed only in that column and mainly along the surface of the trays located in the lower section of the column. The phenomenon was observed subsequently to a modification of the original plant layout that caused an increase of the operating temperatures and turbulence of the process stream inside the column.     

Optimal design and control of a reactive distillation system

This article presents the design and control of a reactive distillation system utilizing recent advances in mixed integer dynamic optimization. A high fidelity dynamic model is used to predict the behavior of the process under time-varying disturbances. Design and control decisions, involving both discrete and continuous variables, are simultaneously optimized leading to a more economically attractive and better controlled system than that obtained by following a sequential optimization approach. It is shown that the resulting design and control scheme can guarantee feasible operation under bounded uncertainty at a minimum total average cost, representing ～17% savings over the original design.     

Advance warning for loss of separation in an industrial distillation column

This paper describes the development of a data‐driven advance warning system for the onset of loss of separation in an industrial distillation column. The system would enable preventive actions to avoid several hours of bad operation and subsequent recovery of the process. Data of more than 2 years of process operation were used to identify and validate various monitoring systems based on both static principal component analysis (PCA) and dynamic PCA. Despite the presence of autocorrelation in the data, only minor differences in advance warning were observed between PCA and dynamic PCA. The developed system provides warnings for 35% to 45% of the observed periods of bad column operation, with respective advance warning times of 16 and 6 minutes. It proves a valuable additional tool to monitor the operation of the distillation column and avoid losses of product, with the potential of reducing bad operation (and the associated costs) by up to 45% and substantially improving overall process reliability.     

Experimental transient performance of a heat pump equipped with a distillation column

A series of experiments were conducted on a heat pump equipped with a distillation column. The system was operated with R32 and with a 30/70% by mass mixture of R32/134a to examine the difference between the transient performance trends with a pure fluid (R32), and those with a zeotropic mixture (R32/134a). Additionally, the effects of varying heat transfer fluid mass flow, compressor speed, and accumulator sump heat input were examined. Each test was 1 h in duration. The heat pump capacities did not generally achieve steady state during the R32/134a tests. Steady state was generally achieved during the R32 tests. As a percentage of the final (end-of-test) capacity, the rate of capacity increase was greater during the R32/134a tests than during those conducted with the pure fluid. The R32/134a tests exhibited capacity oscillations early in each transient that were not present during the R32 tests. The results show that circulating refrigerant mass and composition are the primary controlling factors with regard to transient capacity.     

酯交换反应在制备生物柴油上的应用

生物柴油因其环境友好且可再生作为矿物柴油的替代燃料而备受关注,生物柴油主要通过均相酸碱催化、脂肪酶催化、超临界法和固体酸碱催化的酯交换反应制备得到,但各种制备方法各有优劣,均相酸碱催化法反应迅速,转化率高但存在后续处理复杂,污染严重等问题;脂肪酶催化法反应条件温和,对原料中的水和游离脂肪酸不敏感,不需要过量的甲醇参与反应,后续处理工序简单,但酶的成本过高,这是制约其商业化发展的最大阻碍;超临界法是制备生物柴油的新技术,反应迅速,不需要催化剂,油脂转化率非常高,但其反应需要高温高压且能耗很大;固体酸碱催化剂腐蚀性小可以重复使用,后续分离工序简单,对环境的冲击较弱。其中负载型固体碱催化剂催化油脂酯交换反应将成为制备生物柴油的一个主要发展方向。     

空分设备精馏塔的设计与研究

介绍精馏塔的设计与工艺制造,着重分析了精馏塔塔盘结构形式的确定、筛板塔和规整填料塔的水力学计算、精馏塔的强度计算与稳定性校核。     

Metal-organic framework-derived Mg-Zn hybrid nanocatalyst for biodiesel production

Controlled synthesis of metal–organic framework (MOF)-derived Mg-Zn hybrid nanostructure was demonstrated for the development of basic catalysts applied in biodiesel production from soybean oil. Two types of Mg-Zn hybrid nanostructures were successfully fabricated under different atmospheres (Ar, air), (1) MgO nanoparticles encapsulated in Zn-based MOF (MgO@Zn-MOF) and (2) MgO nanoparticles uniformly decorated on ZnO nanoparticles derived from Zn-MOF (MgO@ZnO), respectively. Ultrafine MgO nanoparticles (<5 nm for MgO@Zn-MOF and ≈10 nm for MgO@ZnO) were successfully synthesized and homogeneously dispersed in the MOF-derived Mg-Zn hybrid nanostructures. Significant increases in the specific surface area (i.e., a maximum of 1048.5 m²/g) and corresponding basicity (i.e., by a maximum of 2.1 times) were achievable by using MOF-based strategy comparing to the Mg-Zn catalyst prepared by a conventional solution-based approach. High 3-cycle stability and high yields of fatty acid methyl esters at a stoichiometric feed ratio 3 were both achievable, 67.6% and 73.3%, by using MgO@Zn-MOF and MgO@ZnO as the catalysts, respectively. The work demonstrates a prototype study of utilizing MOF to develop high-performance basic nanocatalysts through fundamental understanding of material synthesis by design versus their corresponding activities.     

响应面法优化PSSA/PVA共混膜催化酯化制备生物柴油

采用响应面法考察聚苯乙烯磺酸(PSSA)/聚乙烯醇(PVA)共混型催化膜催化酯化制备生物柴油工艺中催化膜用量、醇油质量比、反应时间和反应温度及其交互作用对酯化率的影响,结果发现,各因素对转化率影响顺序为:醇油比＞催化剂用量＞反应温度＞反应时间;同时,醇油比与催化剂量的交互作用对转化率的影响最强,而与反应时间相关的交互作...     

Experimental pure fluid and binary mixture performance in a heat pump equipped with a distillation column

An experimental heat pump system that included a distillation column, accumulator/sump, and heater was experimentally investigated using two different working fluids, R32 and a mixture of R32/134a. Performance variations with changes in sump heater power, condenser and evaporator heat transfer fluid flow, and compressor speed were examined. Heating capacity generally increased with increases in the factors tested. Heating capacity increases were generally smaller with the R32/134a tests than with the R32 tests, except with variations in sump heater power. An increase in sump heater power caused a pronounced increase in the circulating R32 concentration during the mixture tests, and the heating capacity increased markedly. The increase in heating capacity with sump heater power during the R32/134a tests was on par with the increase with compressor power during these same tests. The increase in capacity with sump heater power during the R32/134a tests also was substantial even when compared with the capacity increase with compressor speed during the R32 tests.     

Thermodynamic evaluation of distillation columns using exergy loss profiles: a case study on the crude oil atmospheric distillation column

This paper presents a case study on the crude oil atmospheric distillation column of Tabriz refinery plant to show the applicability of exergy loss profiles in thermodynamic examination of the different retrofit options. The atmospheric distillation column of Tabriz refinery has been revamped as a consequence of increase of the plant capacity to 100,000 bpd. To cover the deficit of feedstock of the revamped unit, a blend of the existing feedstock with imported crude oil is used as a feedstock. However, to investigate how the blend of these two different types of crudes as a feedstock has an influence on the operating conditions, the examination of the column is needed. Exergy as a comprehensive thermodynamic property which translates the temperature, pressure and composition change into a common unit has been chosen to evaluate the distillation column thermodynamically. Furthermore, the exergy loss profile of the base case serves as a scoping tool to pinpoint the source of inefficiencies. Then, the exergy loss profile as a screening tool has found the retrofit options which are likely to yield greatest energy saving from a list of retrofit options proposed by the industrial partner. In the presented case study, the exergy loss profile identifies the best retrofit option with 17.16% reduction in exergy losses, which finally lead to 3.6% reduction of primary fuel demand.     

Life prediction of service exposed reactor and distillation column materials used in a petrochemical industry

Determination of mechanical properties is a powerful method for investigating and assessing the performance of service exposed materials. The present paper highlights the trend recently observed in service exposed (38 years) plain carbon steels used as reactor and distillation column materials in a petrochemical industry. Health assessment of both base and welded joints was made using destructive accelerated stress rupture and tensile tests at different temperatures, and some nondestructive tests. So far as the remaining life at 520°C is concerned, it is possible to obtain a life of about 1.00 lakh h at the respective hoop stress level of both materials, provided no localized damage in the form of cracks or dents have been developed. It is recommended that a health check may be carried out after 5 years of service exposure at 520°C.     

隔板蒸馏塔技术及其在空气分离中的潜在应用

隔板蒸馏塔是完全热耦合蒸馏,具有节能、投资低的优点。文章介绍了隔板蒸馏塔的原理、结构及设计方法,并指出了它在空气分离中的潜在应用。     

Spent coffee grounds for biodiesel production and other applications

This work evaluates the possibility of using spent coffee grounds (SCG) for biodiesel production and other applications. An experimental study was conducted with different solvents showing that lipid content up to 6 wt% can be obtained from SCG. Results also show that besides biodiesel production, SCG can be used as fertilizer as it is rich in nitrogen, and as solid fuel with higher heating value (HHV) equivalent to some agriculture and wood residues. The extracted lipids were characterized for their properties of acid value, density at 15 °C, viscosity at 40 °C, iodine number, and HHV, which are negatively influenced by water content and solvents used in lipid extraction. Results suggest that for lipids with high free fatty acids (FFA), the best procedure for conversion to biodiesel would be a two-step process of acid esterification followed by alkaline transesterification, instead of a sole step of direct transesterification with acid catalyst. Biodiesel was characterized for its properties of iodine number, acid value, and ester content. Although these quality parameters were not within the limits of NP EN 14214:2009 standard, SCG lipids can be used for biodiesel, blended with higher-quality vegetable oils before transesterification, or the biodiesel produced from SCG can be blended with higher-quality biodiesel or even with fossil diesel, in order to meet the standard requirements.     

制备生物柴油的负载型固体碱催化剂研究进展

介绍了用于制备生物柴油的负载型固体碱催化剂的最新研究进展,对金属氧化物和负载型固体碱催化剂载体进行了详细的讨论,并对负载型固体碱催化剂的研究提出了建议。     

Damage assessment of service exposed reactor and distillation column materials of a petrochemical industry

This work highlights quantification of normalized creep damage incorporating uncertainty with respect to Larson–Miller parameter (LMP) at various intervals (with service exposure) of a 55 years service exposed reactor and distillation column materials of a petrochemical industry. Usually, remaining life is predicted from extrapolation of stress vs. LMP plot without incorporating the uncertainty involved in calculation of LMP values. Uncertainty involved in calculating LMP value has been given prime importance in this work because it is a function of rupture time. Variability of normalized creep damage for reactor and column materials is well approximated with the aid of Weibull distribution. As expected, it is observed that the distributions shift towards the higher range of damage with increase in service exposure time.     

火灾事故对空分设备精馏塔器的影响分析

介绍在某钢厂40000m3/h空分设备安装过程中发生的一起火灾事故,叙述火灾事故现场勘察工作,分析了火灾事故的原因对空分设备精馏塔器的破坏程度,为防止类似事故的再次发生,提出了一些防范措施。     

Optimal ecodesign selection for biodiesel production in biorefineries through multicriteria decision making

Clean Technologies and Environmental Policy - Nowadays, a large part of daily activities is associated with the use of fossil fuels. Therefore, the excessive exploitation and related pollution have...