1,721,007 research outputs found
Performance analysis of hybrid system of multi effect distillation and reverse osmosis for seawater desalination via modeling and simulation
Get PDFYesThe coupling of thermal (Multi Stage Flash, MSF) and membrane processes (Reverse Osmosis, RO) in desalination systems has been widely presented in the literature to achieve an improvement of performance compared to an individual process. However, very little study has been made to the combined Multi Effect Distillation (MED) and Reverse Osmosis (RO) processes. Therefore, this research investigates several design options of MED with thermal vapor compression (MED_TVC) coupled with RO system. To achieve this aim, detailed mathematical models for the two processes are developed, which are independently validated against the literature. Then, the integrated model is used to investigate the performance of several configurations of the MED_TVC and RO processes in the hybrid system. The performance indicators include the fresh water productivity, energy consumption, fresh water purity, and recovery ratio. Basically, the sensitivity analysis for each configuration is conducted with respect to seawater conditions and steam supply variation. Most importantly, placing the RO membrane process upstream in the hybrid system generates the overall best configuration in terms of the quantity and quality of fresh water produced. This is attributed to acquiring the best recovery ratio and lower energy consumption over a wide range of seawater salinity.The coupling of thermal (Multi Stage Flash, MSF) and membrane processes (Reverse Osmosis, RO) in desalination systems has been widely presented in the literature to achieve an improvement of performance compared to an individual process. However, very little study has been made to the combined Multi Effect Distillation (MED) and Reverse Osmosis (RO) processes. Therefore, this research investigates several design options of MED with thermal vapor compression (MED_TVC) coupled with RO system. To achieve this aim, detailed mathematical models for the two processes are developed, which are independently validated against the literature. Then, the integrated model is used to investigate the performance of several configurations of the MED_TVC and RO processes in the hybrid system. The performance indicators include the fresh water productivity, energy consumption, fresh water purity, and recovery ratio. Basically, the sensitivity analysis for each configuration is conducted with respect to seawater conditions and steam supply variation. Most importantly, placing the RO membrane process upstream in the hybrid system generates the overall best configuration in terms of the quantity and quality of fresh water produced. This is attributed to acquiring the best recovery ratio and lower energy consumption over a wide range of seawater salinity
Design and economic evaluation of solar-powered hybrid multi effect and reverse osmosis system for seawater desalination
Get PDFYesReducing the cost of fresh water has always been a major concern in the desalination industry. A solar powered hybrid multi-effect distillation and reverse osmosis desalination plant (MED+RO) has been designed and optimised from an economical point of view in a previous work by the same authors. In the present study, the possibility of coupling the desalination plant with a photovoltaic (PV) solar farm is investigated, with the aim of generating electricity at low cost and in a sustainable way. A detailed mathematical model for the PV system has been implemented from the literature. Interestingly, the model can predict the cost of the PV system in terms of capital cost and electricity cost per kWh considering the input data of solar irradiation, duration of daylight and technical specification of a real solar module. Consequently, the solar PV model has been combined with the desalination model, which enables to estimate the cost of fresh water per cubic meter. Data about four locations, namely Isola di Pantelleria (IT), Las Palmas (ES), Abu Dhabi (UAE), and Perth (AUS), have been used to economically test the feasibility of installing the proposed plant, and especially of the PV solar farm.Reducing the cost of fresh water has always been a major concern in the desalination industry. A solar powered hybrid multi-effect distillation and reverse osmosis desalination plant (MED+RO) has been designed and optimised from an economical point of view in a previous work by the same authors. In the present study, the possibility of coupling the desalination plant with a photovoltaic (PV) solar farm is investigated, with the aim of generating electricity at low cost and in a sustainable way. A detailed mathematical model for the PV system has been implemented from the literature. Interestingly, the model can predict the cost of the PV system in terms of capital cost and electricity cost per kWh considering the input data of solar irradiation, duration of daylight and technical specification of a real solar module. Consequently, the solar PV model has been combined with the desalination model, which enables to estimate the cost of fresh water per cubic meter. Data about four locations, namely Isola di Pantelleria (IT), Las Palmas (ES), Abu Dhabi (UAE), and Perth (AUS), have been used to economically test the feasibility of installing the proposed plant, and especially of the PV solar farm
Cost evaluation and optimisation of hybrid multi effect distillation and reverse osmosis system for seawater desalination
Get PDFYesIn this research, the effect of operating parameters on the fresh water production cost of hybrid Multi Effect Distillation (MED) and Reverse Osmosis (RO) system is investigated. To achieve this, an earlier comprehensive model developed by the authors for MED + RO system is combined with two full-scale cost models of MED and RO processes collected from the literature. Using the economic model, the variation of the overall fresh water cost with respect to some operating conditions, namely steam temperature and steam flow rate for the MED process and inlet pressure and flow rate for the RO process, is accurately investigated. Then, the hybrid process model is incorporated into a single-objective non-linear optimisation framework to minimise the fresh water cost by finding the optimal values of the above operating conditions. The optimisation results confirm the economic feasibility of the proposed hybrid seawater desalination plant
Optimisation of multi effect distillation based desalination system for minimum production cost for freshwater via repetitive simulation
No full textThe shortage of fresh water resources is a global problem which requires a prompt solution. Thus, the multi effect distillation (MED) was successfully used for the production of fresh water from seawater. Despite the use of MED desalination system extensively, the influence of the number of effects on the fresh water production cost has not been covered in the open literature. Thus, this paper tries to rectify this specific challenge via simulation at given operating conditions of seawater salinity and temperature. The study is performed using a detailed mathematical model contains the suitable cost correlations. gPROMS model builder suite has been used to carry out an extensive simulation. The results of the study show that the lowest fresh water production cost can be achieved at an optimal number of effects of 17 for a certain operating conditions
Optimisation of multi effect distillation based desalination system for minimum production cost for freshwater
No full textThe multi effect distillation (MED) process has been extensively used for seawater desalination as a prominent process to produce high quality freshwater. However, the impact of number of effects in the MED process-based seawater desalination on the fresh water production cost has not been critically evaluated in the literature. Therefore, the aim of this study is to resolve this particular challenge via the simulation for a given seawater concentration and temperature conditions. The simulation is carried out using a comprehensive MED process model coupled with appropriate cost functions within gPROMS model builder software. The simulation results show that selecting the optimal number of the MED effects as 17 is important to achieve the lowest fresh water production cost for a given seawater operating conditions
Minimisation of Energy Consumption via Optimisation of a Simple Hybrid System of Multi Effect Distillation and Permeate Reprocessing Reverse Osmosis Processes for Seawater Desalination
No full textMulti Effect Distillation (MED) and Reverse Osmosis (RO) processes have been expansively explored for fresh water production from seawater resources. Interestingly, the performance indicators including energy consumption of different proposed arrangements of hybrid system of MED and RO processes have been analysed in a previous study by the same authors. This in turn has explored the feasibility of a simple design of permeate reprocessing RO process and MED process of hybrid system that corresponding the lowest energy consumption compared to other experienced arrangements of hybrid system. However, this design still operated at a significantly high level of energy utilisation measured in kWh per m3 of produced water. In this research, the lowest possible energy consumption of the chosen hybrid system is investigated via the embedment of an optimisation framework in the same author's previous operation model for the same design. Occasionally, the optimisation problem is framed as a Nonlinear Programming problem to locate the optimal control variables of the associated RO process within their upper and lower limits to achieve the main objective function. This in turn has resulted in mitigating the total energy utilisation of the hybrid system with satisfying a constraint of high-quality produced water
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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