A simple,reliable and fast algorithm for the simulation of multicomponent distillation columns

This work has developed a simple, reliable and fast algorithm for the simulation of multicomponent distillation columns, where any equilibrium stage can accept a feed-stream and/or a vapor-side-stream and/or liquid-side-stream. The new scheme considers internal molar overflows and constant relative volatilities to avoid the need of heat balances and vapor–liquid equilibrium calculations. The solution scheme is founded on a Newton-based formulation in block algebra, which relies in a simple, reliable and fast algorithm. Although the proposed calculation scheme can be classified as an approximate method, it is very useful when accurate phase equilibrium and enthalpy data are lacking. Numerical experimentations show good agreement with the results obtained with well-known rigorous simulation approaches.     

Nonlinear constrained optimization using the flexible tolerance method hybridized with different unconstrained methods

This paper proposes the use of the flexible tolerance method (FTM) modified with scaling of variables and hybridized with different unconstrained optimization methods to solve real constrained optimization problems. The benchmark problems used to analyze the performance of the methods were taken from G-Suite functions. The original method (FTM) and other four proposed methods: (ⅰ) FTM with scaling of variables (FTMS), (ⅱ) FTMS hybridizedwith BFGS (FTMS-BFGS), (ⅲ) FTMS hybridizedwithmodified Powell'smethod (FTMS-Powell) and (ⅳ) FTMS hybridized with PSO (FTMS-PSO), were implemented. The success rates of the methods were 80%, 100%, 75%, 95% and 85%, for FTM, FTMS, FTMS-BFGS, FTMS-Powell and FTMS-PSO, respectively. Numerical experiments including real constrained problems indicated that FTMS gave the best performance, followed by FTMSPowell and FTMS-PSO. Despite the inferior performance compared to FTMS and FTMS-Powell, the FTMS-PSOmethod presented some advantages since good different initial points could be obtained, which allowexploring different routes through the solution space and to escape from local optima. The proposedmethods proved to be an effective way of improving the performance of the original FTM.     

An improved flexible tolerance method for solving nonlinear constrained optimization problems:Application in mass integration

This paper proposes the use of the flexible tolerance method(FTM) modified with adaptive Nelder–Mead parameters and barrier to solve constrained optimization problems. The problems used to analyze the performance of the methods were taken from G-Suite functions, and the methods with the best performance were applied in mass integration problems. Four methods were proposed:(1) flexible tolerance method(FTM) using adaptive parameters(FTMA),(2) flexible tolerance method with scaling(FTMS) and with adaptive parameters(FTMAS),(3) FTMS including the barrier modification(MFTMS) and(4) MFTMS hybridized with PSO(MFTMS-PSO). The success rates of these methods were 100%(MFTMS), 85%(MFTMS-PSO), 40%(FTMAS) and 30%(FTMA).Numerical experiments indicated that the MFTMS could efficiently and reliably improve the accuracy of global optima. In mass integration, the method was able, from current process situation, to reach the optimum process configuration that includes integration issues, which was not possible using FTM in its standard formulation. The hybridization of FTMS with PSO(without barrier), FTMS-PSO, was also able to solve mass integration problems efficiently.     

Using redundancy to strengthen the relaxation for the global optimization of MINLP problems

In this paper we present a strategy to improve the relaxation for the global optimization of non-convex MINLPs. The main idea consists in recognizing that each constraint or set of constraints has a meaning that comes from the physical interpretation of the problem. When these constraints are relaxed part of this meaning is lost. Adding redundant constraints that recover that physical meaning strengthens the relaxation. We propose a methodology to find such redundant constraints based on engineering knowledge and physical insight.     

An Effective Approach for Process Parameter Optimization in Injection Molding of Plastic Housing Components

Determining optimal process parameter settings is critical work that extraordinarily influences productivity, quality, and costs of production. Previously, numerous engineers conventionally used trial-and-error processes or Taguchi's parameter design method to determine optimal process parameter settings. However, the application of these methods has some shortcomings. This research applies Taguchi's parameter design method, regression analysis, and the Davidon-Fletcher-Powell method to propose a novel approach for determining the optimal process parameter settings of plastic injection molding under single quality characteristic considerations. This novel approach can avoid shortcomings that originate from the application of trial-and-error processes or the conventional Taguchi parameter design method. The research results revealed that the proposed novel approach can effectively help engineers determine optimal process parameter settings and achieve competitive advantages of product quality and costs.     

气体水合物生成过程强化方法研究现状

气体水合物因其特殊的物理化学特性,已被气体分离、二氧化碳捕集与封存、海水淡化、气体储运等诸多领域学者广泛研究。但气体水合物生成条件较为苛刻、生成速率及储气能力较商业化应用还有较大差距。本工作从气体水合物生成条件、生成速率、储气能力等角度,分别综述了机械强化、外场作用、添加剂等强化方法对气体水合物生成过程的强化原理、技术特征及其研究现状;综合比较分析了各种强化方法的优势及存在的问题;展望了各强化方法的未来发展方向及其适用领域;特别是针对气体水合物法海水淡化的技术特征和关键问题,提出以外电场强化气体水合物法海水淡化过程的新思路。     

涂层组分对堇青石脱硝催化剂性能的影响

为了探究涂层组分对整体式低温选择性催化还原（SCR）脱硝催化剂性能的影响,本文使用锰氧化物（MnO _x ）、氧化物涂层（TiO₂、SiO₂及Al₂O₃）、堇青石（CC）基体制备整体式涂层催化剂,考察催化剂牢固度以及脱硝活性。结果表明：在200℃ 时,对于MnO _x /Al₂O₃/CC催化剂,MnO _x 负载率为6%（质量分数）时脱硝效率最高为95%;对于MnO _x /TiO₂/CC,负载率为6%~12%时脱硝效率相差不大,为75%左右;对于MnO _x /SiO₂/CC,负载率12%时脱硝效率80%。样品牢固度排列顺序如下：MnO _x /Al₂O₃/CC > MnO _x /SiO₂/CC > MnO _x / TiO₂ /CC。通过BET、SEM、TG、Raman、H₂-TPR等测试与分析方法发现：影响催化剂性能的因素主要为活性组分MnO _x 状态以及载体性能的差异。Al₂O₃涂层比表面积适中,作为载体活性好;SiO₂涂层虽然比表面积大、牢固度好,但作为载体活性差;TiO₂作为涂层比表面积较小,溶胶中溶剂挥发快使得涂层表面不均匀。     

Novel bound contraction procedure for global optimization of bilinear MINLP problems with applications to water management problems

We propose a new method to obtain the global optimum of MINLP problems containing bilinearities. Our special method that contracts the bounds of one variable at a time allows reducing the gap between a linear lower bound and an upper bound obtained solving the original problem. Unlike some methods based on variable partitioning, our bound contraction procedure does not introduce new integers or intervals. We illustrate the method by applying it to water management problems.     

Quantitively evaluation of fillers' alignment for targeted manufacturing of functional composite materials

Filler-reinforced composite materials are widely used in numerous domains such as energy, optoelectronics, chemistry, and so forth, owing to their versatile microstructures, excellent properties, and low fabrication cost. By finely regulating the distribution and orientation of fillers in the base material, composite materials with fantastic thermal, chemical, and mechanical properties have been demonstrated, which are also known as “metamaterials”. For the anisotropic fillers, the orientation of fillers is crucial for designing and predicting the properties of composite materials. However, accurate and efficient evaluation of fillers' orientation remains a challenge, which severely hinders the microstructural design and topological optimization of composite materials. To solve this problem, a bidirectional pixel-traversal method which combines with microscopic image processing was developed to evaluate the orientation of fillers in composite materials. Specifically, a vertical orientation maximization algorithm was designed to evaluate the oriented degree and oriented direction of the whole fillers, and a crossing traversal algorithm was designed to evaluate the oriented angle of individual filler. Further, this method was applied to the evaluation of microscopic images from different researches. The evaluated results show a high accuracy (average error is less than 2%) and wide applicability in the evaluation of different types of fillers. This method reveals the underlying relationship between microscopic filler orientation and macroscopic composites properties, which paves a new way for the direct optimization and processing of composite materials.     

A new approach for global optimization of a class of MINLP problems with applications to water management and pooling problems

One of the biggest challenges in solving optimization engineering problems is rooted in the nonlinearities and nonconvexities, which arise from bilinear terms corresponding to component material balances and/or concave functions used to estimate capital cost of equipments. The procedure proposed uses an MILP lower bound constructed using partitioning of certain variables, similar to the one used by other approaches. The core of the method is to bound contract a set of variables that are not necessarily the ones being partitioned. The procedure for bound contraction consists of a novel interval elimination procedure that has several variants. Once bound contraction is exhausted the method increases the number of intervals or resorts to a branch and bound strategy where bound contraction takes place at each node. The procedure is illustrated with examples of water management and pooling problems. © 2011 American Institute of Chemical Engineers AIChE J, 58: 2320–2335, 2012     

Investigation of thermoluminescence and kinetic parameters of gamma ray exposed LiF: Sm3+, Eu3+ nanophosphors for dosimetric applications

Thermoluminescence (TL) properties of LiF: Sm³⁺ (0.05?mol%) co-doped with Eu³⁺ (0.02, 0.04, 0.06, 0.08?mol%) nanophosphor for the applications of TL dosimetry have been studied. The nanophosphors have been synthesized by chemical co-precipitation method at 8?pH value. The phase purity of the prepared samples has been confirmed by using X-ray diffraction (XRD) data. The XRD peaks broadening revealed the formation of the nanostructure, complemented by the TEM image. For TL studies, the samples have been irradiated with gamma rays using ⁶⁰Co source in the irradiation dose range of 0.1?kGy to 30?kGy. In gamma exposed samples, the TL glow curve consists of single glow peak at 410?K and three shoulder peaks at 475?K, 550?K and 632?K. The dosimetry properties such as the effects of exposure doses, heating rates and fading characteristics have also been studied. The kinetic parameters such as activation energy (E), the frequency factors (s) and order of kinetic (b) of the glow curves have also been calculated by using Chen's peak shape method. The linear behavior of TL intensity with radiation doses and low fading shows that the LiF: Sm³⁺, Eu³⁺ Nanophosphor is a potential candidate for dosimetry applications.     

Combinatorial chemistry methods for coating development: VI. Correlation of high throughput screening methods with conventional measurement techniques

Combinatorial chemistry has proven to be a valuable tool for the development of new compounds. In the pharmaceutical industry, where combinatorial chemistry began, the approach has been instrumental in the high-speed development of new drugs. Due to the overwhelming success of the combinatorial methodology in the pharmaceutical industry, it has been recently applied to materials development. We have recently developed a combinatorial factory capable of preparing and evaluating on the order of 100 organic clear coatings in a day.

One of the most challenging aspects of the creation of the combinatorial factory was the development of the high throughput screening (HTS) methods for the primary coating properties of interest such as optical clarity, abrasion resistance, adhesion, and weatherability. For each property, an entirely new method was developed that allowed for rapid measurement of these properties on very small samples. This paper describes various aspects of the development of these novel measurement systems including the correlation of the HTS methods with conventional, industry standard measurement methods.     

Design of memetic algorithms for the efficient optimization of chemical process synthesis problems with structural restrictions

In Urselmann et al., 2011a, Urselmann et al., 2011b we presented a memetic algorithm (MA) for the design optimization of reactive distillation columns. The MA is a combination of a problem-specific evolutionary algorithm (EA) that optimizes the design variables and a mathematical programming (MP) method that solves the continuous sub-problems with fixed discrete decisions which are proposed by the EA to local optimality. In comparison to the usual superstructure formulation, the search space of the MA is significantly reduced without excluding feasible solutions. The algorithm computes many different local optima and can handle structural restrictions and discontinuous cost functions. In this contribution, a systematic procedure to modify the MA to solve more complex design problems is described and demonstrated using the example of a reactive distillation column with an optional side- or pre-reactor with structural restrictions on the number of streams. New concepts to handle connected and optional unit operations are proposed.     

Modeling and optimization methods of integrated production planning for steel plate mill with flexible customization

With diversified requirements and varying manufacturing environments, the optimal production planning for a steelmill becomes more flexible and complicated. The flexibility provides operators with auxiliary requirements through an implementable integrated production planning. In this paper, a mixed-integer nonlinear programming (MINLP) model is proposed for the optimal planning that incorporates various manufacturing constraints and flexibility in a steel plate mill. Furthermore, two solution strategies are developed to overcome theweakness in solving the MINLP problem directly. The first one is to transformthe original MINLP formulation to an approximate mixed integer linear programming using a classic linearization method. The second one is to decompose the originalmodel using a branch-and-bound based iterative method. Computational experiments on various instances are presented in terms of the effectiveness and applicability. The result shows that the second method performs better in computational efforts and solution accuracy.     

A new flow reactor for the treatment of polluted water with microwave and ultrasound

Microwave (MW) and high‐intensity ultrasound (US) provide innovative techniques for the degradation of persistent organic pollutants (POPs). When Fenton's reagent is used to treat industrial wastes, organic pollutants are degraded by highly reactive hydroxyl radicals (HO·) that can oxidize almost any organic compound to carbon dioxide and water. These reactions, when carried out under US or MW, are faster and much more efficient. The present work assesses the combined effect of US and MW using a new flow reactor developed in our laboratory. In this 5 L pilot reactor the liquid was pumped in parallel through a modified domestic MW oven and through a cell where it was irradiated with two US generators working at 20 and 300 kHz, while MW irradiation took place in a modified domestic oven. We studied the degradation of 2,4‐dibromophenol (0.1 g L^?1 in water) by Fenton's reagent, assessing the contribution of each energy source to the overall effect, and found that MW and US‐300 kHz played the main role. A modest amount of oxidant (6 mL 30% H₂O₂ per 1 L of polluted water) sufficed to achieve complete degradation within 6 h, at which time organic compounds were no longer detectable. Even if no Fenton's reagent was added, about one half of the pollutant was degraded after 3 h irradiation. Copyright © 2007 Society of Chemical Industry     

Application of the simplex simulated annealing technique to nonlinear parameter optimization for the SAFT-VR equation of state

A non-equilibrium simplex simulated annealing algorithm is applied as a global optimization method to parameter optimization for an equation of state based on the generalized statistical associating fluid theory incorporating potentials of variable range. The parameters are determined by optimizing the calculated phase behaviour of a number of pure solvents, such as water and alcohols, and aqueous electrolyte solutions. The optimized parameters obtained via the simulated annealing algorithm are compared to those obtained using the simplex method and, for the electrolyte solutions, a gradient-based quasi-Newton method. In the case of the pure solvents, the lowest values of the objective function have been obtained using the simulated annealing technique in six out of the seven studied systems, while for the electrolyte solutions the method results in the lowest values in nine systems out of 11; in the other systems the local methods have resulted in lower values of the objective function. It is observed that both for the solvents and the solutions considered the parameters obtained using the annealing technique are theoretically justifiable, follow physically meaningful trends, and can more easily be generalized; such results provide a measure of confidence that the annealing method does converge to the global minimum in the majority of the studied systems. For pure solvents a simple generalization of parameters leads to accurate predictions for other solvents in the same homologous series. In the case of the electrolyte systems correlations among parameters obtained via simulated annealing can be qualitatively identified, and a simple correlation is proposed which simplifies the molecular models. This is generally not the case for the two local minimization methods considered which, except for a few specific cases, lead to parameters showing no general trends, despite the calculated phase behaviour being almost identical.     

Vapor liquid equilibrium data for alcohol n-Amylamine binary systems at 333.15 K. Reduction of the experimental data by a novel model-free method

Vapor liquid equilibrium measurements for the binary systems of n-amylamine with methanol, ethanol and 1-propanol at 333.15 K are reported. The measurements were made in a static equilibrium cell of the Van Ness type and the experimental data were reduced using a model-free method. This model-free method is an adaptation of the method of Mixon et al. in which a material balance is introduced to correct for the mols of the gas phase. Second virial coefficients of n-amylamine and cross second virial coefficients for the binary systems were measured in this work and parameters for the Tsonoupolos correlation are reported.     

不同方法制备的铈锰固溶体及其催化醇胺偶联反应

为了研究不同制备方法对铈锰固溶体形貌、结构及其表面物种等的影响,阐明铈锰固溶体结构与其催化性能之间的关系,通过纳米铸型法、水热法、共沉淀法、热分解法制备出4种理论掺锰量为15%的铈锰固溶体〔Ce_(0.85)Mn_(0.15)O_x,n(Ce)∶n(Mn)=0.85∶0.15〕。采用XRD、FESEM、TEM、N_2-吸附脱附、ICP-OES、XPS对催化剂进行物化性质表征,并以苯甲醇和苯胺偶联反应作为探针反应来评估其催化性能。结果表明,以纳米铸型法制备的铈锰固溶体催化剂具有最佳的催化活性,其苯胺转化率达到了67.9%,N-苄叉苯胺的选择性为99.4%,时空产率为0.56 mmol/(g_(cat)·h)。与用其他3种方法制备的铈锰固溶体相比,纳米铸型法制备的铈锰固溶体具有较大的表面积、特定的介孔结构,催化剂表面拥有较高相对含量的Ce~(3+)、Mn~(3+),有利于吸附和活化氧分子,这些因素均有利于催化醇胺偶联反应。     

Quality control of camellia oil based on HPLC fingerprinting techniques combined with chemometric methods for triglycerides

Triglycerides (TAGs) play an important role in the physiological function of vegetable oils. Camellia oil has a variety of good physiological functions. Therefore, a qualitative and quantitative method for the determination of TAGs in camellia oil by high-performance liquid chromatography-diode array detector/electro spray ionization mass spectrometry was developed. The 16 TAGs that separated were identified and quantified by peak-area normalization. In addition, the major TAGs in camellia oil were OOO (25.25%), OLO (20.72%), POL (9.23%), OLL (8.22%), and OOP (8.22%). Moreover, the content of oleic acid in camellia oil was 81.74%. Using fingerprint techniques, 15 common peaks in 12 samples were selected as characteristic peaks to evaluate the differences in the composition of camellia oil samples. In addition, the samples were further classified by chemometric methods. It is shown that the camellia oil samples with high similarity from two cities in the main producing areas of Zhejiang province could be further classified according to the planting areas by the combination of chromatographic fingerprints and chemometric methods.