scholarly journals Membrane-Based Processes: Optimization of Hydrogen Separation by Minimization of Power, Membrane Area, and Cost

Processes ◽  
2018 ◽  
Vol 6 (11) ◽  
pp. 221 ◽  
Author(s):  
Patricia Mores ◽  
Ana Arias ◽  
Nicolás Scenna ◽  
José Caballero ◽  
Sergio Mussati ◽  
...  
Keyword(s):  
Cost Minimization ◽  
Initial Guess ◽  
Total Power ◽  
Total Annual Cost ◽  
Membrane Area ◽  
Trade Offs ◽  
Processing Plants ◽  
Cost Minimization Problem ◽  
H2 Recovery ◽  
Total Membrane

This work deals with the optimization of two-stage membrane systems for H2 separation from off-gases in hydrocarbons processing plants to simultaneously attain high values of both H2 recovery and H2 product purity. First, for a given H2 recovery level of 90%, optimizations of the total annual cost (TAC) are performed for desired H2 product purity values ranging between 0.90 and 0.95 mole fraction. One of the results showed that the contribution of the operating expenditures is more significant than the contribution of the annualized capital expenditures (approximately 62% and 38%, respectively). In addition, it was found that the optimal trade-offs existing between process variables (such as total membrane area and total electric power) depend on the specified H2 product purity level. Second, the minimization of the total power demand and the minimization of the total membrane area were performed for H2 recovery of 90% and H2 product purity of 0.90. The TAC values obtained in the first and second cases increased by 19.9% and 4.9%, respectively, with respect to that obtained by cost minimization. Finally, by analyzing and comparing the three optimal solutions, a strategy to systematically and rationally provide ‘good’ lower and upper bounds for model variables and initial guess values to solve the cost minimization problem by means of global optimization algorithms is proposed, which can be straightforward applied to other processes.

scholarly journals Optimal Design of a Two-Stage Membrane System for Hydrogen Separation in Refining Processes

Processes ◽  
2018 ◽  
Vol 6 (11) ◽  
pp. 208 ◽  
Author(s):  
Ana Arias ◽  
Patricia Mores ◽  
Nicolás Scenna ◽  
José Caballero ◽  
Sergio Mussati ◽  
...  
Keyword(s):  
Annual Cost ◽  
Optimal Solution ◽  
Membrane System ◽  
Operating Conditions ◽  
Total Annual Cost ◽  
Membrane Area ◽  
Expansion Turbine ◽  
Process System ◽  
H2 Recovery ◽  
Process System Engineering

This paper fits into the process system engineering field by addressing the optimization of a two-stage membrane system for H2 separation in refinery processes. To this end, a nonlinear mathematical programming (NLP) model is developed to simultaneously optimize the size of each membrane stage (membrane area, heat transfer area, and installed power for compressors and vacuum pumps) and operating conditions (flow rates, pressures, temperatures, and compositions) to achieve desired target levels of H2 product purity and H2 recovery at a minimum total annual cost. Optimal configuration and process design are obtained from a model which embeds different operating modes and process configurations. For instance, the following candidate ways to create the driving force across the membrane are embedded: (a) compression of both feed and/or permeate streams, or (b) vacuum application in permeate streams, or (c) a combination of (a) and (b). In addition, the potential selection of an expansion turbine to recover energy from the retentate stream (energy recovery system) is also embedded. For a H2 product purity of 0.90 and H2 recovery of 90%, a minimum total annual cost of 1.764 M$·year−1 was obtained for treating 100 kmol·h−1 with 0.18, 0.16, 0.62, and 0.04 mole fraction of H2, CO, N2, CO2, respectively. The optimal solution selected a combination of compression and vacuum to create the driving force and removed the expansion turbine. Afterwards, this optimal solution was compared in terms of costs, process-unit sizes, and operating conditions to the following two sub-optimal solutions: (i) no vacuum in permeate stream is applied, and (ii) the expansion turbine is included into the process. The comparison showed that the latter (ii) has the highest total annual cost (TAC) value, which is around 7% higher than the former (i) and 24% higher than the found optimal solution. Finally, a sensitivity analysis to investigate the influence of the desired H2 product purity and H2 recovery is presented. Opposite cost-based trade-offs between total membrane area and total electric power were observed with the variations of these two model parameters. This paper contributes a valuable decision-support tool in the process system engineering field for designing, simulating, and optimizing membrane-based systems for H2 separation in a particular industrial case; and the presented optimization results provide useful guidelines to assist in selecting the optimal configuration and operating mode.

AND-OR-XOR NETWORK SYNTHESIS WITH AREA-POWER TRADE-OFF

2011 ◽  
Vol 20 (06) ◽  
pp. 1019-1035 ◽  
Author(s):  
SAMBHU NATH PRADHAN ◽  
M. TILAK KUMAR ◽  
SANTANU CHATTOPDHYAY
Keyword(s):  
Boolean Function ◽  
Solution Space ◽  
Leakage Power ◽  
Total Power ◽  
Synthesis Process ◽  
Network Synthesis ◽  
Trade Off ◽  
Delay Performance ◽  
Trade Offs ◽  
Power Trade

In this paper, a heuristic based on genetic algorithm to realize multi-output Boolean function as three-level AND-OR-XOR network performing area power trade-off is presented. All the previous works dealt with the minimization of number of product terms only in the two sum-of-product-expressions representing a Boolean function during AND-OR-XOR network synthesis. To the best of knowledge this is the first ever effort to incorporate total power, that is, dynamic and leakage power along with the area (in terms of number of product terms) during three-level AND-OR-XOR networks synthesis. The synthesis process, without changing the delay performance results in lesser number of product terms compared to those reported in the literature. It also enumerates the trade-offs present in the solution space for different weights associated with area, dynamic power, and leakage power of the resulting circuit.

Particle Swarm Optimization for Cost Reduction in Mobile Location Management Using Reporting Cell Planning Approach

2017 ◽  
pp. 171-189 ◽  
Author(s):  
Smita Parija ◽  
Sudhansu Sekhar Singh ◽  
Swati Swayamsiddha
Keyword(s):  
Particle Swarm Optimization ◽  
Cellular Network ◽  
Cost Minimization ◽  
Location Management ◽  
Particle Swarm ◽  
Location Update ◽  
Swarm Optimization ◽  
Cell Planning ◽  
Wireless Mobile Communication ◽  
Cost Minimization Problem

Location management is a very critical and intricate problem in wireless mobile communication which involves tracking the movement of the mobile users in the cellular network. Particle Swarm Optimization (PSO) is proposed for the optimal design of the cellular network using reporting cell planning (RCP) strategy. In this state-of-the-art approach, the proposed algorithm reduces the involved total cost such as location update and paging cost for the location management issue. The same technique is proved to be a competitive approach to different existing test network problems showing the efficacy of the proposed method through simulation results. The result obtained is also validated for real network data obtained from BSNL, Odisha. Particle Swarm Optimization is used to find the optimal set of reporting cells in a given cellular network by minimizing the location management cost. This RCP technique applied to this cost minimization problem has given improved result as compared to the results obtained in the previous literature.

scholarly journals A quantitative model of traffic between plasma membrane and secondary lysosomes: evaluation of inflow, lateral diffusion, and degradation.

1988 ◽  
Vol 107 (6) ◽  
pp. 2109-2115 ◽  
Author(s):  
J P Draye ◽  
P J Courtoy ◽  
J Quintart ◽  
P Baudhuin
Keyword(s):  
Plasma Membrane ◽  
Half Life ◽  
Plasma Membranes ◽  
Lateral Diffusion ◽  
Quantitative Model ◽  
Lysosomal Membrane ◽  
Membrane Area ◽  
Rat Fibroblasts ◽  
Secondary Lysosomes ◽  
Total Membrane

We present here a mathematical model that accounts for the various proportions of plasma membrane constituents occurring in the lysosomal membrane of rat fibroblasts (Draye, J.-P., J. Quintart, P. J. Courtoy, and P. Baudhuin. 1987. Eur. J. Biochem. 170: 395-403; Draye, J.-P., P. J. Courtoy, J. Quintart, and P. Baudhuin. 1987. Eur. J. Biochem. 170:405-411). It is based on contents of plasma membrane markers in purified lysosomal preparations, evaluations of their half-life in lysosomes and measurements of areas of lysosomal and plasma membranes by morphometry. In rat fibroblasts, structures labeled by a 2-h uptake of horseradish peroxidase followed by a 16-h chase (i.e., lysosomes) occupy 3% of the cellular volume and their total membrane area corresponds to 30% of the pericellular membrane area. Based on the latter values, the model predicts the rate of inflow and outflow of plasma membrane constituents into lysosomal membrane, provided their rate of degradation is known. Of the bulk of polypeptides iodinated at the cell surface, only 4% reach the lysosomes every hour, where the major part (integral of 83%) is degraded with a half-life in lysosomes of integral to 0.8 h. For specific plasma membrane constituents, this model can further account for differences in the association to the lysosomal membrane by variations in the rate either of lysosomal degradation, of inflow along the pathway from the pericellular membrane to the lysosomes, or of lateral diffusion.

Opening Ratio Effect on Electrowetting Droplet Actuation on Perforated Membranes

2009 ◽  
Author(s):  
Yuejun Zhao ◽  
Sung Kwon Cho
Keyword(s):  
Power Consumption ◽  
Sampling Method ◽  
Critical Issue ◽  
Membrane Area ◽  
Ratio Effect ◽  
Lower Power ◽  
Analytical Results ◽  
Hole Area ◽  
Opening Ratio ◽  
Total Membrane

We have previously developed a microparticle sampling method in which electrowetting-actuated droplets sweep and pick up microparticles trapped on a perforated membrane. In this configuration, a critical issue is to increase the opening ratio (ratio of opening hole area to the total membrane area) in the perforated membrane as much as possible since the higher the opening ratio the lower power consumption in the process of air suction. In contrast, increasing the opening ratio hampers successful electrowetting operations of droplets and thus sampling of microparticles. In this study, we analytically investigate effects of the opening ratio on electrowetting operations. In particular, we are looking at the reversibility of electrowetting operation. Then, we fabricate testing devices to verify the analytical results in the range of the opening ratio up to about 90%. We will also discuss detailed challenging issues in microfabrication to reach such a high opening ratio.

Core-Based GRASP for Delay-Constrained Group Communications

2013 ◽  
Vol 4 (4) ◽  
pp. 1-22
Author(s):  
Zrinka Lukač ◽  
Manuel Laguna
Keyword(s):  
Data Stream ◽  
Cost Minimization ◽  
Multimedia Technology ◽  
Computational Results ◽  
Adaptive Search ◽  
End To End Delay ◽  
Efficient Delivery ◽  
Asymmetric Networks ◽  
Cost Minimization Problem

The recent development in network multimedia technology has created numerous real-time multimedia applications where the Quality-of-Service (QoS) requirements are quite rigorous. This has made multicasting under QoS constraints one of the most prominent routing problems. The authors consider the problem of the efficient delivery of data stream to receivers for multi-source communication groups. Efficiency in this context means to minimize cost while meeting bounds on the end-to-end delay of the application. The authors adopt the multi-core approach and utilize SPAN (Karaman and Hassane, 2007)—a core-based framework for multi-source group applications — as the basis to develop greedy randomized adaptive search procedures (GRASP) for the associated constrained cost minimization problem. The procedures are tested in asymmetric networks and computational results show that they consistently outperform their counterparts in the literature.

scholarly journals Genetic algorithm for network cost minimization using threshold based discounting

2003 ◽  
Vol 7 (4) ◽  
pp. 207-228 ◽  
Author(s):  
Hrvoje Podnar ◽  
Jadranka Skorin-Kapov
Keyword(s):  
Genetic Algorithm ◽  
Communication Networks ◽  
Branch And Bound ◽  
Cost Minimization ◽  
Total Flow ◽  
Cpu Time ◽  
Network Cost ◽  
Cost Minimization Problem ◽  
The Cost ◽  
Different Sources

We present a genetic algorithm for heuristically solving a cost minimization problem applied to communication networks with threshold based discounting. The network model assumes that every two nodes can communicate and offers incentives to combine flow from different sources. Namely, there is a prescribed threshold on every link, and if the total flow on a link is greater than the threshold, the cost of this flow is discounted by a factor α. A heuristic algorithm based on genetic strategy is developed and applied to a benchmark set of problems. The results are compared with former branch and bound results using the CPLEX® solver. For larger data instances we were able to obtain improved solutions using less CPU time, confirming the effectiveness of our heuristic approach.

scholarly journals PEMROGRAMAN LINEAR INTEGER DENGAN ENAM VARIABEL ORIENTASI KARGO UNTUK MASALAH MINIMISASI BIAYA PEMUATAN MULTI-KONTAINER

2020 ◽  
Vol 15 (3) ◽  
pp. 162-168
Author(s):  
Dian Pratiwi Sahar ◽  
Mohammad Thezar Afifudin
Keyword(s):  
Linear Programming ◽  
Integer Linear Programming ◽  
Programming Model ◽  
Cost Minimization ◽  
Mathematic Model ◽  
Transport Cost ◽  
Container Loading ◽  
Volume Load ◽  
Cost Minimization Problem ◽  
The Given

Penelitian ini bertujuan untuk mengembangkan model matematika untuk masalah minimisasi biaya pemuatan multi-kontainer dengan enam variabel orientasi kargo. Masalah ini dirumuskan sebagai model pemrograman linier biner integer untuk meminimalkan biaya. Faktor-faktor yang dipertimbangkan dalam formulasi termasuk alokasi kargo, lokasi kargo, hubungan kargo, dan orientasi kargo. Sedangkan, biaya yang dipertimbangkan termasuk biaya muatan volume kontainer ke kargo dan biaya transportasi kargo ke kontainer. Validasi model dilakukan melalui percobaan numerik pada ukuran kecil kargo dan kontainer. Hasil penelitian menunjukkan bahwa model dengan konsep orientasi kargo yang dikembangkan dapat menyelesaikan masalah sesuai dengan parameter numerik yang diberikan. Abstract[Integer Linear Programming with Six Cargo Orientation Variables for Multi-Container Loading Cost Minimization Problem] This research aims to develop the mathematic model for multi-container loading cost minimization problems with six cargo orientation variables. The problem is formulated as a binary integer linear programming model to minimize costs. The factors considered in the formulation include cargo allocation, cargo location, cargo relations, and cargo orientation. Whereas, the costs considered include the container volume load cost to cargo and the cargo transport cost to the container. Model validation is performed through numerical experiments on the small size of cargo and containers. The results show that the model with developed cargo orientation concept can solve the problem according to the given numerical parameters.Keywords: integer programming; cargo orientation; container loading; cost minimization

scholarly journals Energy-Spectral Efficiency Trade-Offs in Full-Duplex MU-MIMO Cloud-RANs with SWIPT

2021 ◽  
Vol 2021 ◽  
pp. 1-21
Author(s):  
Xuan-Xinh Nguyen ◽  
Ha Hoang Kha
Keyword(s):  
Energy Efficiency ◽  
Spectral Efficiency ◽  
Optimization Problems ◽  
Iterative Algorithms ◽  
Full Duplex ◽  
Total Power ◽  
Achievable Rate ◽  
Power Splitting ◽  
Radio Access ◽  
Trade Offs

The present paper investigates the trade-offs between the energy efficiency (EE) and spectral efficiency (SE) in the full-duplex (FD) multiuser multi-input multioutput (MU-MIMO) cloud radio access networks (CRANs) with simultaneous wireless information and power transfer (SWIPT). In the considered network, the central unit (CU) intends to concurrently not only transfer both energy and information toward downlink (DL) users using power splitting structures but also receive signals from uplink (UL) users. This communication is executed via FD radio units (RUs) which are distributed nearby users and connected to the CU through limited capacity fronthaul (FH) links. In order to unveil interesting trade-offs between the EE and SE metrics, we first introduce three conventional single-objective optimization problems (SOOPs) including (i) system sum rate maximization, (ii) total power minimization, and (iii) fractional energy efficiency maximization. Then, by making use of the multiobjective optimization (MOO) framework, the MOO problem (MOOP) with the objective vector of the achievable rate and power consumption is addressed. All considered problems are nonconvex with respect to designing variables comprising precoding matrices, compression matrices, and DL power splitting factors; thus, it is extremely intractable to solve these problems directly. To overcome these issues, we develop iterative algorithms by utilizing the sequential convex approximation (SCA) approach for the first two SOO problems and the SCA-based Dinkelbach method for the fractional EE problem. Regarding the MOOP, we first rewrite it as an SOOP by applying the modified weighted Tchebycheff method and, then, propose the iterative algorithm-based SCA to find its optimal Pareto set. Various numerical simulations are conducted to study the system performance and appealing EE-SE trade-offs in the considered system.

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