Optimization Of Unit Operations Research Articles

A two-stage operation optimization model for isolated integrated energy systems with concentrating solar power plant considering multi-energy and multi-type demand response

The isolated integrated energy system coupled with multiple types of energy systems is one of the important ways to guarantee the quality of energy use in remote areas, but due to the lack of external main network’s support and random renewable energy output, there is a greater risk of load cutting, which puts forward higher requirements for the operation optimization of the isolated integrated energy system. Therefore, this paper first constructs a two-stage optimization model from both supply and demand side for the linkage development of resources within the isolated integrated energy system. Secondly, an evaluation index system containing economic benefits and system efficiency is constructed to quantify the comprehensive benefits of the two-stage operation optimization. Finally, a remote area in China is selected as the research background for example analysis. The results show that (1) Due to the low matching between supply and demand of the isolated integrated energy system, the unit operation optimization is only conducted from the energy supply side, and the total load shedding is about 101.402 MW. (2) Considering the load side optimization in the first stage, the demand side resources can be mobilized to improve the supply and demand matching degree. Compared with the second stage optimization in Scenario 1, the internal supply rates in Scenarios 2, 3 and 4 are increased by 0.399, 0.159 and 0.567 respectively, and the system net income is increased by 8990, 18840 and 2310 CNY respectively. Limited by factors, such as the subsidy price on the load side, the demand elasticity matrix and the energy selling price on the energy supply side, there is no negative linear relationship between the amount of load shedding and the improvement of energy supplier’s economic benefits, so it is necessary to consider actual operation scenarios and reasonably arrange operation and dispatching plans.

Selective co-extraction of critical metals from deep ocean polymetallic nodule leachate and preparation of battery-grade Ni-Co-Mn solution

The high-efficient and economic recovery of Ni, Co, and Mn from the leaching solution is critical for the industrial application of deep-ocean polymetallic nodules processing. To reduce the reagent consumption and wastewater generation presented in the individual metal element separation processes, a synergistic solvent extraction (SSX) process that selectively co-extracted Ni, Co, and Mn by the mixed extractant of pyridine carboxylate ester and naphthalene sulfonic acid was developed. Furthermore, the unit operation optimization and the extraction mechanism were systematically investigated. Experimental results demonstrated that almost all the Ni and Co were selectively extracted and left the impurities such as Ca and Mg in the raffinate by the synergistic extraction under optimal conditions. Moreover, a quantitative extraction of Mn could be achieved by controlling the excess coefficient of the organic extractant. By the aid of FTIR, HRMS, and the slope method, the molecular formula of loaded organic was deduced as Ni(C16H25NO2)2(C28H43O3S)2·2H2O, in which structure nickel forms a stable six-coordination complex with the extractant and H2O. Then, a battery-grade Ni/Co/Mn sulfate solution (Ca less than 0.02 mg/L, Mg less than 0.05 mg/L) was produced by stripping with 0.75 mol/L H2SO4 solutions. In conclusion, recovery of Ni, Co, and Mn from the leaching solution of DPN by the co-extraction with the SSX system is a promising alternative for industrial application due to its highly efficient and economic efficiency brought by the short process, less reagent consumption and wastewater discharge.

Optimization of Unit Operations for Microencapsulating Ferrous Fumarate During Scale-Up of Double Fortification of Salt with Iron and Iodine

Abstract Objectives This study evaluates factors responsible for the floating of iron premix in double fortified salt (DFS), which initially affected the large-scale implementation of the salt fortification program in India, and provides solutions to the scale-up of the technology. Materials and Methods To mitigate this time-sensitive scale-up challenge. First, the iron premix samples were obtained from the industrial scale-up pilot studies in India, evaluated for the impact of the amount of coating material (5 per cent, 7.5 per cent, and 10 per cent (in weight)), type of formulation (soy stearin, SEPIFILM and hydroxypropyl methylcellulose), amount of titanium dioxide (25-35 per cent (in weight)) used for color masking; Second, we studied the effect of change in the composition of the coating, from 10 per cent (in weight) soy stearin to a double coat with 5 per cent (in weight) hydroxypropyl methylcellulose and 5 per cent soy stearin or 10 per cent soy stearin and 1 per cent (in weight) lecithin mixture, on particle density, floating or sinking property of the iron premix, and on the stability of iodine in the DFS. Results It was observed that the hydrophobic nature and the amount of soy stearin used for coating caused the floating issue. The double coating with 5 per cent hydroxypropyl methylcellulose and 5 per cent soy stearin was preferred because lecithin in soy stearin enhanced the moisture-aided adverse interaction between iron and iodine. Shelf-life storage studies proved over 80 per cent iodine retention after 12 months of storage in the DFS formulated with iron premix double-coated with hydroxypropyl methylcellulose and soy stearin. Conclusion This proffered solution enabled the full implementation of the double fortification program in India.

Estimating speciation of aqueous ammonia solutions of ammonium bicarbonate: application of least squares methods to infrared spectra

The knowledge of the speciation and of the supersaturation of aqueous solutions of CO2 and NH3 is pivotal for the design and optimization of unit operations, e.g. absorption or crystallization, in the framework of ammonia-based CO2 capture systems.

A Review of Mathematical Programming in Integrated Iron‐ and Steelmaking

AbstractThis paper presents and reviews the current application fields of mathematical programming in integrated iron‐ and steelmaking research. Three different fields of mathematical programming applications are identified and discussed: unit operation optimization, by‐product gas distribution, and integrated system optimization and design. Based on current research activities in the iron and steel industry, development trends for mathematical programming in integrated iron‐ and steelmaking research, such as the cogeneration of chemicals aided by renewable energy grid integration, are presented.

Petroleum heteroatom compounds in various commercial delayed coking liquids: characterized by FT-ICR MS and GC techniques

Delayed coking is an important petroleum resid conversion process. The processability of coking liquids is known to be dependent on the heteroatom compounds present in the coking liquids. Eight commercial delayed coking liquids were characterized by electrospray ionization (ESI) Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS) and gas chromatographic techniques. High relatively abundant heteroatom compounds in the coking liquids were 1–4 aromatic-ring pyridinic nitrogen compounds, carbazoles, benzocarbazoles, phenols, mercaptans, benzothiophenes, dibenzothiophenes, and naphthobenzothiophenes. Coking liquids derived from various feeds had similar compound class types, molecular weight distribution ranges, and double bond equivalents (DBE). However, the concentration of individual compounds and the distribution of DBE versus carbon number of heteroatom compounds varied. A comparison of heteroatom compounds in coker feeds and products revealed the various reaction mechanism of heteroatom compounds occurred during the coking process. The results suggested that molecular-level process models can be developed for optimization of unit operation to obtain desirable products that meet the environmental specifications and quality requirements.

Dielectric properties of four softwood species at low-level radio frequencies for optimized heating and drying

ABSTRACT Dielectric heating and drying are important nontraditional technologies for the phytosanitation and quality dehydration of wood products. Unit operation optimization requires, among others, knowledge of the variable dielectric properties of wood so that an optimum dielectric generator matching wood impedance is maintained throughout the process. For this reason, the dielectric properties of four commercially important west coast softwood species were experimentally obtained at various moisture contents, temperatures, and radio frequencies (RF) between 0.1 and 30 MHz. Measurements were carried out on all-sapwood and all-heartwood specimens in both radial and longitudinal directions. Measurements were also done with specimens that were fully saturated with distilled and seawater. All specimens mostly revealed similar qualitative trends in loss factor changes; that is, increases with moisture content and temperature and decreases with increasing frequency. The measurements carried out in the longitudinal direction showed relatively high loss factor values compared to the radial grain direction. Both distilled and seawater saturated loss factors resulted in similar trends and with absolute values hundreds and in some cases thousand times larger than those for specimens in the hygroscopic range.

Limitations of simple mass transfer models in polydisperse liquid–liquid dispersions

In this work the limitations of standard approaches, commonly used to describe mass transfer in fluid–fluid systems are critically discussed. Emphasis is placed on polydisperse systems, such as liquid–liquid dispersions. In the simplest possible approach the fluid–fluid system is assumed to be monodisperse: namely all the elements of the disperse phase have the same properties. This very simple (albeit inaccurate) approach is the one typically employed for design, scale-up and optimization of unit operations and of the corresponding equipments. The adequacy (or inadequacy) of this model depends on the competition between three phenomena: droplet coalescence, breakage and mass transfer (often enhanced by chemical reactions). When coalescence and breakage dominate, the only polydispersity that has to be accounted for is droplet size, whereas on the contrary, when mass transfer dominates the process, very often polydispersity with respect to both size and chemical composition must be considered. This can be efficiently done by solving the so-called population balance equation with, for example, quadrature-based moment methods. In this work a strategy to evaluate a-priori the complexity of the model to be used, based on time scales, is proposed and tested.

Rheological Behavior of Yeast Paste from the Ethanol Industry

Abstract Moist yeast is a byproduct of the ethanol industry with potential applications in the animal feed and food industries. Presently, knowledge of moist yeast's rheological properties is limited, despite it being crucial for the design and optimization of unit operations involved in the processing of this raw material. The work presented here is a study of the rheological behavior of yeast paste at different solid concentrations (0.15, 0.25, 0.35, 0.45, 0.55, and 0.64 g/mL) and temperatures (20, 30, 40, 50, 60, 70, and 80°C) using a concentric-cylinder rheometer. The experimental results were evaluated using four rheological models. The Power Law model was the best fit, demonstrating pseudoplastic behavior in all concentrations studied. In addition, the dependence of the flow behavior index and the flow consistency index of the Power Law model on temperature and solid concentration was also successfully modeled through a quadratic model and an Arrhenius-type equation, respectively.

Unit operation optimization for the manufacturing of botanical injections using a design space approach: a case study of water precipitation.

Quality by design (QbD) concept is a paradigm for the improvement of botanical injection quality control. In this work, water precipitation process for the manufacturing of Xueshuantong injection, a botanical injection made from Notoginseng Radix et Rhizoma, was optimized using a design space approach as a sample. Saponin recovery and total saponin purity (TSP) in supernatant were identified as the critical quality attributes (CQAs) of water precipitation using a risk assessment for all the processes of Xueshuantong injection. An Ishikawa diagram and experiments of fractional factorial design were applied to determine critical process parameters (CPPs). Dry matter content of concentrated extract (DMCC), amount of water added (AWA), and stirring speed (SS) were identified as CPPs. Box-Behnken designed experiments were carried out to develop models between CPPs and process CQAs. Determination coefficients were higher than 0.86 for all the models. High TSP in supernatant can be obtained when DMCC is low and SS is high. Saponin recoveries decreased as DMCC increased. Incomplete collection of supernatant was the main reason for the loss of saponins. Design space was calculated using a Monte-Carlo simulation method with acceptable probability of 0.90. Recommended normal operation region are located in DMCC of 0.38–0.41 g/g, AWA of 3.7–4.9 g/g, and SS of 280–350 rpm, with a probability more than 0.919 to attain CQA criteria. Verification experiment results showed that operating DMCC, SS, and AWA within design space can attain CQA criteria with high probability.

Research on Continuous Emission Monitoring System in Thermal Power Plant

The system aims to collect reliable emission data in real time, provide the operator with real-time emission parameters, and guide the optimization of unit operation and control of pollutants in flue gas emissions. One kind of continuous emission monitoring system is designed based on PROFIBUS-DP protocol in power plant, the architecture of system is presented and the principle is described in detail.

Monoclonal antibody capture and viral clearance by cation exchange chromatography

Traditionally, post-production culture harvest capture of therapeutic monoclonal antibodies (mAbs) is performed using Protein A chromatography. We investigated the efficiency and robustness of cation exchange chromatography (CEX) in an effort to evaluate alternative capture methodologies. Up to five commercially available CEX resins were systematically evaluated using an experimentally optimized buffer platform and a design-of-experiment (DoE) approach for their ability to (a) capture a model mAb with a neutral isoelectric point, (b) clear three model viruses (porcine parvovirus, CHO type-C particles, and a bacteriophage). This approach identified a narrow operating space where yield, purity, and viral clearance were optimal under a CEX capture platform, and revealed trends between viral clearance of PPV and product purity (but not yield). Our results suggest that after unit operation optimization, CEX can serve as a suitable capture step.

A multi-level simulation approach for the crude oil loading/unloading scheduling problem

An integrated approach for refinery production scheduling and unit operation optimization problems is presented. Each problem is at a different decision making layer and has an independent objective function and model. The objective function at the operational level is an on-line maximization of the difference between the product revenue and the energy and environmental costs of the main refinery units. It is modeled as an NLP and is constrained by ranges on the unit's operating condition as well as product quality constraints. The production scheduling layer is modeled as an MILP with the objective of minimizing the logistical costs of unloading the crude oil over a day-to-week time horizon. The objective function is a linear sum of the unloading, sea waiting, inventory, and setup costs. The nonlinear simulation model for the process units is used to find optimized refining costs and revenue for a blend of two crudes. Multiple linear regression of the individual crude oil flow rates within the crude oil percentage range allowed by the facility is then used to derive linear refining cost and revenue functions. Along with logistics costs, the refining costs or revenue are considered in the MILP scheduling objective function. Results show that this integrated approach can lead to a decrease of production and logistics costs or increased profit, provide a more intelligent crude schedule, and identify production level scheduling decisions which have a tradeoff benefit with the operational mode of the refinery.

A Data Mining Rule Extraction Method for Thermal Power Unit Operation Optimization

A rule extraction method for thermal power unit operation optimization which based on data mining technology is proposed in this paper. Data mining technology is employed to analyze history data stored in real-time/history database of the unit. Stability index, economic index, environmental index and synthetic index are constructed to evaluate the performance of current operating condition. Through comparison analysis on similar operating condition, the best operating parameters and operating mode can be found out at the current condition. Accompanying with data accumulation proceeding in database, nonlinear static model between the unit operation performance index and controllable parameters is drawn over all operating conditions. Effectiveness of this method is illustrated by a practical operation optimization project, in which the realization scheme of operation guidance is also given out.

Moisture Sorption Isotherm Characteristics of Food Products: A Review

Knowledge of the sorption properties of foods is of great importance in food dehydration, especially in the quantitative approach to the prediction of the shelf life of dried foods. Equations for modelling water sorption isotherms are of special interest for many aspects of food preservation by dehydration, including evaluation of the thermodynamic functions of the water sorbed in foods. Knowledge of the thermodynamic properties associated with sorption behaviour of water in foods is important to dehydration in several respects, especially in the design and optimization of unit operation.

A Supervisory Expert System for Integrated Plant-Wide Control

In January 1993, Pyramid Resources began a one year project to implement a plant-wide supervisory expert control system at a large U.S. copper concentrator. The objective of this control system was and continues to be to improve plant profitability through unit operation optimization and global integration of the individual control strategies. This paper documents the key aspects of the project, including: economic and metallurgical benefits, system architecture, concepts of implementation, process control strategies, practical aspects of implementation and conclusions. The expert control system has been used over ninety-five percent of the time since its completion and the benefits are estimated to exceed $50,000 per day.

Current Biotechnological Developments in Belgium

In recent years, actions have been undertaken by the Belgian government to promote process innovation and technical diversification. Research programs are initiated and coordinated by the study committee for biotechnology setup within the Institute for Scientific Research in Industry and Agriculture (IRSIA). As a result of this action, the main areas where biotechnological processes are developed or commercially exploited include plant genetics, protein engineering, hybridoma technology, biopesticides, production by genetic engineering of vaccines and drugs, monoclonal detection of human and animal deseases, process reactors for aerobic and anaerobic wastewater treatment, and genetic modification of yeast and bacteria as a base for biomass and energy. Development research also includes new fermentation technologies principally based on immobilization of microorganisms, reactor design, and optimization of unit operations involved in downstream processing. Food, pharmaceutical, and chemical industries are involved in genetic engineering and biotechnology and each of these sectors is overviewed in this paper.