Cost-effective Optimization Research Articles

Cost Effective Optimization of Centrifuges

Cost Effective Optimization of Centrifuges

Modelling and optimisation of a chemical industry wastewater treatment plant subjected to varying production schedules

AbstractIndustrial wastewater treatment plants (WWTPs) have to provide 100% reliability and availability for the discharging facilities at an industrial site. Varying production schedules at these facilities and specific components occurring in the industrial wastewater considerably hinder the optimisation of industrial WWTPs. In this context it is shown in this paper that model‐based optimisation is an efficient and cost‐reducing way to ensure that an industrial WWTP functions well. The aim of the study presented was two‐fold. The first step was to show the usefulness of a proposed procedure to build and calibrate a model for the industrial WWTP. The second objective was to use the model for optimisation of the WWTP. As an example, a large set of possible production schedules in the different discharging facilities was simulated. Based on these simulations it could be predicted which schedules allow the effluent standards to be met and which do not. The calibrated and validated model was also used to investigate different operating strategies such as the in‐series operation of the two available aeration tanks. In fact, with the model it was shown that a 20% reduction of the degradable COD concentration in the effluent could be achieved by operating the tanks in series instead of in parallel. This case study shows how the approach presented can lead to fast and cost effective modelling and optimisation of an industrial WWTP. Copyright © 2004 Society of Chemical Industry

Multi-channel simulation of regeneration in honeycomb monolithic diesel particulate filters

In recent years advanced computational tools of diesel particulate filter (DPF) regeneration have been developed to assist in the systematic and cost-effective optimization of next generation particulate trap systems. In the present study, we employ a previously validated, state-of-the-art multichannel DPF simulator to study the regeneration process over the entire spatial domain of the filter. Particular attention is placed on identifying the effect of inlet cones and boundary conditions, filter can insulation and the dynamics of “hot spots” induced by localized external energy deposition. Lateral heat losses through the insulation and the periphery of the filter can, as captured by the magnitude of the Nusselt number, Nu, are detrimental to the effectiveness of the regeneration process. A filter can Nu number less than 10 and preferably less than 5 is a good design target for high regeneration efficiency. For the case studied, insulation of the inlet cones can lead to a gain of 30% in regeneration efficiency by eliminating radial temperature gradients at the inlet filter face. The multichannel simulator provides an instructive illustration of the well-appreciated effects of localized hot spot on filter regeneration: hot spots play a more significant role (spread over) when located near the entrance of the filter.

99/02319 Cost effective utilities energy plans optimization and management: Farag, A. S. et al. Energy Convers. Manage., 1999, 40, (5), 527–543

New coal-gas exploration and production in northern Louisiana and south-central Mississippi, Gulf of Mexico Basin, is focused on the Wilcox Group (Paleocene–Eocene), where the depth to targeted subbituminous C to high volatile C bituminous coal beds ranges from 300 to 1680 m, and individual coal beds have a maximum thickness of about 6 m. Total gas content (generally excluding residual gas) of the coal beds ranges from less than 0.37 cm3/g (as-analyzed or raw basis; 1.2 cm3/g, dry, ash free basis, daf) at depths less than 400 m, to greater than 7.3 cm3/g (as-analyzed basis; 8.76 cm3/g, daf) in deeper (> 1,500 m) parts of the basin. About 20 Wilcox coal-gas wells in northern Louisiana produce from 200 to 6485 m3 of gas/day and cumulative gas production from these wells is approximately 25 million m3 (as of December, 2006). U.S. Geological Survey assessment of undiscovered, technically recoverable gas resources in the Gulf of Mexico Coastal Plain, including northern and south-central Mississippi, indicates that coal beds of the Wilcox Group contain an estimated mean total 109.3 million m3 (3.86 trillion ft3) of producible natural gas.To determine the origin of the Wilcox Group coal gases in northern Louisiana, samples of gas, water, and oil were collected from Wilcox coal and sandstone reservoirs and from under- and overlying Late Cretaceous and Eocene carbonate and sandstone reservoirs. Isotopic data from Wilcox coal-gas samples have an average δ13CCH4 value of − 62.6‰ VPDB (relative to Vienna Peedee Belemnite) and an average δDCH4 value of − 199.9‰ VSMOW (relative to Vienna Standard Mean Ocean Water). Values of δ13CCO2 range from − 25.4 to 3.42‰ VPDB. Produced Wilcox saline water collected from oil, conventional gas, and coalbed gas wells have δDH2O values that range from − 27.3 to − 18.0‰ VSMOW. These data suggest that the coal gases primarily are generated in saline formation water by bacterial reduction of CO2. Shallow (< 150 m) Wilcox coal beds containing freshwater have little or no biogenic gas.Molecular and isotopic analyses of gas samples collected from conventional gas and oil wells suggests that both biogenic and thermogenic gases are present in and adjacent to the Wilcox intervals that contain biogenic coal gases. Oil, probably sourced from thermally mature, down-structural-dip parts of the Wilcox Group, is produced from sandstones within the coal-bearing interval. Gas chromatograms of C10+ saturated hydrocarbons from Wilcox oils show a depletion of n-alkanes probably resulting from biodegradation of the oil. Isotopic composition of the gases associated with the oils is of mixed themogenic and biogenic origin (average δ13CCH4 = − 44.4‰ VPDB, and average δDCH4 = − 182.4‰ VSMOW).

Cost effective utilities energy plans optimization and management

Utilities have to develop and recommend integrated, reliable and cost-effective approaches for meeting the future demand and energy needs of their customers. This plan should be updated biennially to provide management with a current basis for making prudent short-term decisions and to establish long-term direction. Integrated resource planning techniques, consistent with the concepts of least-cost planning, should be used as the basis for developing recommendations for the plan. Changes in the national and local energy economy and business environment present significant uncertainty and challenge. In order to manage effectively in this uncertain environment, utilities should place great emphasis on planning. One of the key planning tools used by utilities to help achieve their strategic goals is the energy plan. Resource plans recommended by the energy plan should be considered in conjunction with the overall capital and operating and maintenance expense requirements of the utilities to ensure the ongoing financial integrity of all utility operations. This information, along with engineering judgements, is used in reaching a decision as to which integrated resource plan should be pursued. The energy planning process, documented in this paper, develops and analyzes options available to different utilities for meeting their energy supply obligations. These options include demand-side and supply-side alternatives which are evaluated on an equal basis. Cost-effective options are integrated into plans that achieve the corporate objective of providing reliable service at the lowest reasonable cost under a range of uncertain future conditions. The energy plan develops plans which recognize the contribution to be expected from new energy use management programs and addresses the need for developing flexible plans which are adaptable to changing conditions and quantify the cost of this flexibility as it relates to different supply-side resource decisions. Finally, this energy plan should recommend options that have the flexibility to adapt to a range of uncertain conditions in a reliable and economical fashion.

A Heat and Mass Transfer Model for the Simulation of the Wet Limestone Flue Gas Scrubbing Process

The efficiency of a limestone flue gas scrubber depends on such a large number of coupled parameters that their influence on the absorption cannot be sufficiently investigated using only experimental measurements in pilot or full-scale plants. A systematic and cost-effective optimization of the highly developed technology used today is only possible with the support of a simulation model that is based on fundamental scientific and engineering principles containing a small number of physically well-defined parameters.

Heuristic and randomized optimization for the join ordering problem

Recent developments in database technology, such as deductive database systems, have given rise to the demand for new, cost-effective optimization techniques for join expressions. In this paper many different algorithms that compute approximate solutions for optimizing join orders are studied since traditional dynamic programming techniques are not appropriate for complex problems. Two possible solution spaces, the space of left-deep and bushy processing trees, are evaluated from a statistical point of view. The result is that the common limitation to left-deep processing trees is only advisable for certain join graph types. Basically, optimizers from three classes are analysed: heuristic, randomized and genetic algorithms. Each one is extensively scrutinized with respect to its working principle and its fitness for the desired application. It turns out that randomized and genetic algorithms are well suited for optimizing join expressions. They generate solutions of high quality within a reasonable running time. The benefits of heuristic optimizers, namely the short running time, are often outweighed by merely moderate optimization performance.

The EPRI state-of-the-art cooling water treatment research project a tailored collaboration program

The EPRI Tailored Collaboration State-of-the-Art Cooling Water Treatment Research Program has been initiated with several electric utility participants. Started in January 1995, the program will provide O&M cost reduction through improved cooling water system reliability and operation. This effort is discussed along with the objectives and goals, the participants and project timetable. The program will provide three (3) main results to the participating utilities: cost effective optimization of cooling water treatment, production of a new Cooling Water Treatment Manual and updating of two (2) EPRI software products — SEQUIL and COOLADD. A review of the specific objectives, project timetable and results to date will be presented.

Plasma Process Routes to Synthesis of Carbide, Boride and Nitride Ceramic Powders

ABSTRACTAn iterative technique to develop plasma processing, consisting of identifying materials with unique properties, calculating conversion efficiencies, product purity and power from thermodynamic data for the chemical reactions selected to produce it and modeling the process mathematically and physically to determine capital and labor costs is illustrated with production of silicon carbide and titanium diboride in Alcoa's DC plasma facility. The work shows that submicron silicon carbide and titanium diboride containing less than 0.2% oxygen can be produced with plasmas at costs competitive with traditional processes. It has also been reported that aluminum nitride, a material which has the high thermal conductivity needed for high power electronic substrates, can be satisfactorily produced by reacting aluminum powder with nitrogen in an RF plasma system. Future application of plasmas for production of ceramics will depend on discovery of unique properties and cost effective process optimization.

A Practical Method for the Rational Design of Ship Structures

A practical, rationally based method is presented for the automated optimum design of ship structures. The method required the development of (a) a rapid, design-oriented finite-element program for the analysis of ship structures; (b) a comprehensive mathematical model for the evaluation of the capability of the structure; and (c) a cost-effective optimization algorithm for the solution of a large, highly constrained, nonlinear redesign problem. These developments have been incorporated into a program called SHIPOPT. The efficiency and robustness of the method is illustrated by using it to determine the optimum design of a complete cargo hold of a general-purpose cargo ship. The overall dimensions and the design loads are the same as those used in the design of the very successful SD14 series of ships. The redesign problem contains 94 variables, a nonlinear objective function, and over 500 constraints of which approximately half are non-linear. Program SHIPOPT required approximately eight minutes of central processing unit time on a CDC CYBER 171 to determine the optimum design.

Reusable roadside impact attenuation devices

Advanced computer and materials technologies are employed to develop reusable, maintenance-free roadside safety hardware. These devices dissipate large amounts of kinetic energy, undergo significant deformations and strains without fracturing, and regain their original shapes and energy dissipation potentials upon removal of the impact load. It is demonstrated that computer simulation is a cost effective design optimization tool whose use can reduce the number of expensive full scale crash tests required to develop new safety hardware.