Seawater Desalination Plant Research Articles

Influence of brine on hydration reaction of calcium sulfoaluminate and slag blended cement

A study was conducted to develop an eco-friendly, low-carbon cement and to find new applications for waste brine discharged from seawater desalination plants. As the binder, a binary blended binder of calcium sulfoaluminate type K expanding agent (CSA) classified as ACI 223R-10 and slag was used. The CSA content was 0%, 10%, 20%, and 30% substituted. For mixed water, freshwater and brine were used. The brine promoted the hydration reaction of the CSA to promote the formation of ettringite and increased the pore content of 50 nm or less to form a dense matrix, thereby improving the mechanical performance. The 20% CSA sample exhibited the best strength for freshwater and brine samples. However, for the 30% CSA, a decrease in strength was measured, which is due to the excessive expansion effect. Mixing the CSA–slag-blended cement and brine suggests the possibility of its application as a new construction material.

Materials and Corrosion in Seawater Reverse Osmosis Plants: A Review

Desalination is emerging as one of the most promising solutions to extraction and increasing global demand for drinking water. A water purification process called reverse osmosis (RO), in which dissolved solids are separated from solutions by partially permeable membranes. Advances in membrane technology have resulted in the removal of up to 99% of salts in seawater. However, the process and system of seawater treatment RO are associated with many problems, such as scaling and fouling of the membranes, corrosion of the pumps, valves and piping system due to the highly concentrated salt solution and high chemical consumption. Nowadays, these problems have become very critical as they severely affect the desalination process and also massively deteriorate the performance and lifetime of the system components and materials. To ensure that the desalination process is always the best option for a low-maintenance, highly efficient and cost-effective system and process, a comprehensive study of these problems is essential. Therefore, this article addresses the characteristics of metallic materials and corrosion problems in the reverse osmosis process of seawater desalination, as well as the best solutions to focus on and evaluate for an optimal seawater desalination process, and the selection of the category of duplex stainless steels suitable for seawater desalination plants to reduce maintenance, avoid plant shutdown and ensure plant safety.

Integrated Nanogrid for the Impressed Current Cathodic Protection System in Desalination Plant

The impressed current cathodic protection (ICCP) scheme is a more reliable and efficient method of corrosion prevention mechanism than the sacrificial method. Currently, the grid connected transformer rectifier units supported with a battery banks are used for the ICCP-based corrosion protection system in the desalination plant. This conventional method is entirely grid-dependent, more expensive, and suffers during prolonged grid failure. The present trend of industrialization is the application of multi-renewable energy sources based on a nanogrid to power the station’s auxiliary power supply. This paper introduces a concept of distributed energy resources (DERs) operated integrated nanogrid (ING) system to provide a stable power supply solution to the ICCP scheme. A 100-million-litter per day capacity-based seawater desalination plant (SWDP) in India has been chosen as the test station. The conceptual hardware design and operational logic details for smooth integration of the integrated nanogrid module into the ICCP scheme of the Desalination plant is proposed. This research aims to investigate the behaviour of DERs during on-grid, off-grid and switching over from one mode of operation to another and vice-versa by using the accelerated Gauss–Seidel method in ETAP software (version 16.0.0). The simulation results confirm that the ING suffers from a high-frequency change rate during islanded operation, and in some cases, a complete blackout occurs. A PLC-based Smart Versatile ING Controller has been suggested to overcome the blackout issue. Finally, it has been proven that the stability of an industrial power system can be improved further by introducing the ING module into it.

Use of Alteromonas sp. Ni1-LEM Supernatant as a Cleaning Agent for Reverse-Osmosis Membranes (ROMs) from a Desalination Plant in Northern Chile Affected by Biofouling.

Biofouling refers to the undesirable growth of microorganisms on water-submerged surfaces. Microfouling, the initial state of biofouling, is characterized by aggregates of microbial cells enclosed in a matrix of extracellular polymeric substances (EPSs). In seawater desalination plants, filtration systems, such as reverse-osmosis membranes (ROMs), are affected by microfouling, which decreases their efficiency in obtaining permeate water. The existing chemical and physical treatments are expensive and ineffective; therefore, controlling microfouling on ROMs is a considerable challenge. Thus, new approaches are necessary to improve the current ROM cleaning treatments. This study demonstrates the application of Alteromonas sp. Ni1-LEM supernatant as a cleaning agent for ROMs in a desalination seawater plant in northern Chile (Aguas Antofagasta S.A.), which is responsible for supplying drinking water to the city of Antofagasta. ROMs treated with Altermonas sp. Ni1-LEM supernatant exhibited statistically significant results (p < 0.05) in terms of seawater permeability (Pi), permeability recovery (PR), and the conductivity of permeated water compared with control biofouling ROMs and those treated with the chemical cleaning protocol applied by the Aguas Antofagasta S.A. desalination plant.

Numerical analysis of a solar assisted chemical looping combustion combined power and sea water desalination plant

Chemical looping combustion (CLC) with solar integration for power generation is viewed as a technology that would have many economic and environmental benefits. This is because the use of solar systems to provide heating for the CLC process could lead to improved power plant performance and significant reduction of emissions. The performance of energy resources for CLC systems can be further improved via poly-generation. In this study, a novel solar assisted, methane fired CLC power plant with CO2 capture combined with waste heat utilization for sea water desalination is proposed. The plant receives a total thermal energy input of 20 MW. Ni based oxygen carrier is used for the oxygen transfer cycle. The proposed model is developed using Aspen plus software with the consideration of the conservation of mass, momentum and energy. In the study, the effect of using solar energy for the provision of the required heating for the endothermic reaction process in CLC is thoroughly examined by varying the solar share. The results show that an efficiency of 60.56% for the system can be obtained when the solar energy contributes 15–20% of total thermal energy. The system performance is relatively poor for solar share values below 15%. The system performance is further improved (approximately three percentage points) by integrating it with a desalination unit. A parametric study was conducted to ensure that the operating parameters are at their optimum levels. The study also examines the effect of certain key operational parameters for the desalination system such as sea water temperature, sea water salinity and the top brine temperature. The water production is increased with the decrease of top brine temperature and the increase of sea water temperature and salinity.

Dynamic modelling and simulation of industrial scale multistage flash desalination process

Multistage Flash (MSF) desalination process is still a dominant process, especially in the Gulf region, to produce high quality freshwater. Although there has been energy price surge in recent years, MSF process will continue to operate in that region for some foreseeable future. The key challenge is how to make such processes still profitable. Understanding the dynamics of any processes under uncertainty and disturbances is very important to make a process operationally feasible and profitable. The main aim of this work is to understand the dynamics of industrial scale MSF process using high fidelity and reliable process model. For this purpose, a detailed dynamic model for the MSF process incorporating key and new features is developed and validated against the actual data of a large-scale seawater desalination plant. The model is then used to study the behaviour of large scale MSF processes for disturbances in steam temperature, feed temperature and the recycle brine flow rate. The simulation results show that the last stage requires a longer time to settle compared to the preceding stages. In addition, steam temperature shows insignificant influence on the performance ratio compared to the inlet seawater temperature and recycle brine flow rate. Furthermore, it is found that the productivity of plant can increase in the winter compared to that in the summer. However, this benefit comes at the expense of increased steam consumption in the winter, resulting in a low performance ratio.

Integration of a Geothermal Plant in a System with High Renewable Energy Penetration for Desalination Plant Self-Consumption

The scarcity of water resources on the island of Gran Canaria (Canary Islands, Spain) is such that 88% of the water supply for human consumption comes from seawater desalination plants. This type of process has a high specific energy consumption. Gran Canaria has an isolated electrical system of low robustness. In this paper, a geothermal plant is designed and integrated into a system that already has non-dispatchable renewable generation (wind and photovoltaic) in order to meet, based on a self-consumption regime, the energy demand of a high-capacity desalination plant. The aim is for the diversified renewable system to improve the stability and management of renewable electrical energy generation. Geothermal plant production can adapt to the energy balance between demand and non-dispatchable renewable generation. The geothermal plant’s design is based on an organic Rankine cycle and its resulting power is 4.16 MW. Its integration in the renewable generation system significantly improves the contribution of renewables in meeting the desalination plant’s energy demand and therefore reducing its dependency on the island’s electrical system. The mean cost of electrical energy generation with the diversified renewable system is 57.37 EUR/MWh, considerably lower than the mean cost of conventional generation on Gran Canaria of 153.9 EUR/MWh.

Intelligent process optimisation based on cutting-edge emotional learning for performance evaluation of NF/RO of seawater desalination plant

As decision-makers, researchers encounter highly dynamic, complex problems requiring suitable nature-based and industrial quantitative tools for performance analyses, syntheses, and modelling. This study employed a new-generation emotional artificial neural network (EANN) and other stand-alone approaches to model the performance of hybrid nanofiltration (NF) and reverse osmosis (RO) desalination plants in terms of permeate recovery (PR) (%) and permeate flow rate (PFR) (m3/h). With the obtained experimental data, augmented Dickey-Fuller (ADF) and Philip Perron tests, evaluated using the Akaike information criterion and Schwarz information criterion, were employed to assess stability and stationarity. Nonlinear input-variable feature selection based on mutual information and neuro-sensitivity analysis (NSA) was conducted on several input variables before modelling. The EANN was compared with stand-alone predictive models: backpropagation neural network and classical stepwise regression. Predictive simulations were evaluated using the Nash–Sutcliffe model efficiency coefficient (NSE), correlation coefficient (CC), mean absolute error (MAE), determination coefficient (DC), root mean square error (RMSE), and two-dimensional Taylor graphical visualisation. For PR, in the calibration phase, the NSE and MAE (%) were 27–99 % and 0.0064–0.1410, respectively. For PFR, NSE and MAE (m3/h) were 50–99 % and 0.0064–0.1410, respectively. The bibliography review indicated the popularity of artificial intelligence (AI) applications in desalination. Results revealed that this new-generation EANN demonstrated superior accuracy over all models; accordingly, it can serve as a reliable tool for evaluating the performance of NF/RO hybrid seawater desalination plants.

Experimental and economic investigation of sweeping gas membrane distillation/pervaporation modules using novel pilot scale device

With the increasing demand for freshwater, the disposal of the highly saline water resulting from industrial processes and seawater desalination plants has become a critical environmental problem. Reverse osmosis (RO) cannot endure high salinity feed streams higher than 75 g/L. Membrane distillation (MD) and pervaporation (PV) techniques have been proving their capability to desalinate high-salinity brines. The sweeping gas MD/PV (SGMD/SGPV) technique has a lower heat loss to the permeate side as air is used to carry the water vapour, but it is rarely evaluated at larger scales. A pilot-scale desalination device was designed and constructed for an MD/PV surface area of 1.17 m2 to analyse the performance of SGMD/SGPV. The resultant fluxes reached 13.2 L m−2h−1 and 9.2 L m−2h−1 at feed salinities of 35 g/L and 125 g/L, respectively, with 99.6 % salt rejection (% SR) at 70 °C. Furthermore, an economic analysis of the overall system shows that it requires minimal maintenance costs to be competitive in water production. Overall, it provides an appealing alternative to small-scale, stand-alone desalination systems capable of generating high-quality drinking water from very salty water.

Biological and corrosion aspects of a multi-stage flash seawater desalination plant after deaerator modification

Biological and corrosion aspects of a multi-stage flash seawater desalination plant after deaerator modification

The pricing method for abandoned wind power contract between wind power enterprises and desalination plants in bilateral transactions

In Northeast China’s electric power auxiliary service market, guiding interruptible load users to participate in bilateral transactions is an effective measure to ease the difficulty of grid peak regulation and improve the utilization rate of wind power. Aiming at the lack of theoretical guidance in the current bilateral transactions, this paper proposes a two-stage pricing (TSP) method. Firstly, the freshwater supply and demand balance model of the desalination plant is constructed. The upper-level optimization model of bilateral transaction for profit maximization of the desalination plant is constructed. Then, considering the profit distribution among transaction parties and constraints on wind power utilization, a low-level calculation model of wind power pricing is constructed. Finally, the TSP method is applied to the numerical analysis of bilateral transaction between a desalination plant and a wind power company. The TSP method jointly optimizes the dispatching scheme between the variable speed pump and the water storage tank of the desalination plant. Under the constraints of reasonable profit distribution and wind power utilization, the transaction price finally converges to a range acceptable to both parties. The TSP method can effectively improve the utilization rate of wind power and optimize the flexibility of energy utilization. • A detailed mixed-integer linear programming (MILP) model is developed for desalination plants. • A model for seawater desalination plants to participate in bilateral trading markets is proposed. • A TSP method for calculating the price of bilateral transactions is proposed. • The TSP method can effectively optimize the flexibility of energy utilization.

FLOW ENERGY ANALYSIS OF REVERSE OSMOSIS UNIT IN SEAWATER DESALINATION PLANT WITH ENERGY RECOVERY DEVICE

The demand of water is increasing day by day because of population explosion and rapid urbanisation. In this regard, desalination is one of the prominent technologies for providing potable water from saline aqueous media. Among available methods of desalination, seawater reverse osmosis is commercially viable and practiced in many countries of the world. But high energy use is one of the drawbacks of reverse osmosis process. Hence, this study aimed to analyse flow energy of reverse osmosis unit in seawater desalination plant with energy recovery device. A conventional material and energy balances is applied for the analysis. From the analysis, zero loss is observed in recirculation pump and significant loss of 66.65 kJ/s is estimated in energy recovery device. It could be concluded that energy recovery device is a suitable option to reduce the energy use in reverse osmosis unit.

골드심을 이용한 해수담수화 이동형 선박의 급수 모델 적용성 평가

Because of climate change, damage to coastal and island regions due to abnormal weather patterns such as drought and typhoons has become a more severe threat. In particular, there is a high risk of water shortages on islands that import water from the mainland by ship because of a lack of a water supply system and groundwater. In addition, ship-based water transport systems have not been well-planned; thus, they involve many simple round-trip operations between the mainland and individual islands, which raises costs. In this study, we attempted to reduce the operating costs of water supply shipments by analyzing water usage on islands and planning a new method of operation. To achieve this, the water supply system is modeled using the GoldSim program, widely employed for water resource and management analysis. The applicability of a shipboard seawater desalination plant was also evaluated. Three different scenario models were analyzed for the applying shipboard seawater desalination plant to island regions. When calculating the minimum travel distance to ensure a stable water supply, it was found that using a shipboard seawater desalination plant minimized the operating space. Because the traveling length of a ship is directly related to costs, the results of this analysis are expected to have economic benefits for water supply systems.

Landfill Leachate Treatment by Using Second-Hand Reverse Osmosis Membranes: Long-Term Case Study in a Full-Scale Operating Facility.

Landfill leachate (LFL) has a complex inorganic, organic and microbiological composition. Although pressure-driven membrane technology contributes to reaching the discharge limits, the need for frequent membrane replacement (typically every 1-3 years) is an economical and environmental limitation. The goal of this work is to evaluate the feasibility of using second-hand reverse osmosis (RO) membranes to treat LFL in an industrially relevant environment. End-of-life RO membranes discarded from a seawater desalination plant were first tested with brackish water and directly reused or regenerated to fit with requirements for LFL treatment. A laboratory scale test of second-hand membrane reuse was carried out using ultrafiltered LFL. Then, a long-term test in an LFL full-scale facility was performed, where half of the membranes of the facility were replaced. The industrial plant was operated for 27 months with second-hand membranes. The permeate water quality fit the required standards and the process showed a trend of lower energy requirement (up to 12 bar lower transmembrane pressure and up to 9% higher recovery than the average of the previous 4 years). Direct reuse and membrane regeneration were successfully proven to be an alternative management to landfill disposal, boosting membranes towards the circular economy.

Quantitative suitability evaluation and spatial zoning for seawater desalination water intake site selection

Seawater desalination water intake site selection has an important impact on the investment, water production cost, stable operation, and safety of seawater desalination plants. Site selection is affected by many factors, such as the natural geography, ecological environment, and social economy of coastal zones; some constraints can be directly identified as unsuitable areas for these construction projects. For the shallow water intake method of seawater desalination, this study selects suitability evaluation indicators for seawater desalination water intake site selection from the three influencing factors of basic geography, water environment, and industrial development and constructs a suitability evaluation model based on the multifactor spatial overlay analysis of the Geographic Information System platform. This model carries out a quantitative suitability evaluation of the seawater desalination water intake site selection and realizes the suitable spatial zoning for spatially selecting the water intake, thus forming a scientific, quantitative, and spatial suitability evaluation system for this process. The evaluation method was applied in the Rongcheng city offshore area of China and analyzed. The evaluation results showed that the suitable areas for seawater desalination water intake site selection comprised 304.8 square kilometers, which were mainly distributed in the offshore areas in northern Rongcheng city and near the coastline areas of its central and southern regions. The unsuitable areas covered 292.4 square kilometers, mainly distributed in the marine ecological red line areas and the coastal aquaculture areas of Rongcheng city. The evaluation results met the site selection needs of the seawater desalination water intake project in Rongcheng city. This study improves upon the existing method of seawater desalination intake site selection at the theoretical and technical levels and provides a scientific basis for the location selection and planning for water intake in large spatial ranges of coastal waters.

Techno-environmental Simulations for Solar Energy-Powered Seawater Reverse Osmosis Desalination for a Hyper Arid Coastal Region

This study investigates the efficiency of a solar-powered seawater desalination plant (DP) using reverse osmosis for an arid coastal region. The solar models are investigated using local meteorological data, including direct, diffused and global irradiance. The meteorological data are obtained using local typical meteorological data set collected from a ground weather station. The PVsyst simulation tool is used to model a grid-connected solar PV system utilizing three photovoltaic (PV) technologies: thin-film, monocrystalline, and polycrystalline. Three scenarios were considered: restricted area, daily water production and design capacity. The optimum configuration for the restricted area scenario at the seawater DP location considered is an on-grid thin-film module (170 W) with a tilt angle of 20° and an inverter unit of 2000 kW. The solution module area is 15,248 m2. The annual electricity production will be approximately 4251.1 MWh/y, which represents only 3.1% of the DP demand. Thin-films produce higher annual electricity than monocrystalline and polycrystalline silicon by 8.3% and 5.9%, respectively, but require 15.9% and 5.7% more space than monocrystalline and polycrystalline silicon, respectively. For Shuwaikh DP, a 30 MIGD DP will require a PV system with a capacity of 120 MWp at 30° tilt angles and 60 inverters. The design environmental impact was assessed using life cycle assessment (LCA). The carbon footprint will decrease from 7.3 x10-5 to 1.8 x10-5 (kg CO2 equivalent), for the 30 MIGD production. The fossil fuel depletion will decrease by approximately 80%. However, the large number of solar panels and the significant total ground area required for the 30 MIGD. The solar array of 1,531,054 m2 will adversely affect the urban land occupation impact category by 84% and will increase metal depletion by 37%.The response surface optimization indicates that the optimal performance in the coastal region for power desalination plants is achieved when using a thin-film at a tilt angle of 20 o.

ANALYSIS AND FEASIBILITY OF CHEMICAL PRODUCTS REDUCTION IN THE CLEAN IN PLACE OF ULTRAFILTRATION AS A PRE-TREATMENT TECHNOLOGY FOR REVERSE OSMOSIS DESALINATION

The reverse osmosis seawater desalination plants open-intake requires different strategies of pre-treatment to reduce the biofouling and scaling. The UltraFiltration (UF) technology is a recent application to this process. In this work, some alternatives to chemical products reducing in chemically enhanced backwash (CEB) and clean in place (CIP) of a UF rack have been studied. Mainly the sodium hypochlorite consumption, due to its biofouling precursor effect over reverse osmosis membranes. For this purpose, the optimal filtration time has been studied, to get the highest water production prior to the CIP, as well as some modifications in the conventional CIP's, modifying the duration of the stages of the same. The results were compared with the current mode of daily operation of the CEB. The results show that a reduction of up to 60% in the amount of sodium hypochlorite per cubic meter of water produced employed in UF CEB's, mini CIP's and CIP's can be achieved. However, the consumption of the rest of chemical dosing increased notably, and therefore the operating cost of UF also increased. In addition, there was an increase of desalted water consumption to the chemical products removed, up to almost 95,84 %, in comparison with the currently operational mode of CEB. On the other hand, operating the UF plant in the manner proposed requires a automatization of the process and expert staff to programme the control. Therefore, based on the results obtained, the alternatives proposed could reduce the chemical products in use, but it is not conclusive in terms of exploitation operational costs. Key Words: Ultrafiltration, Reverse osmosis, Open-intake, Clean in place, Chemically Enhanced Backwash, chemical products reduction, biofouling, pre-treatment.

Integrated energy system optimal scheduling considering the comprehensive and flexible operation mode of pumping storage.

The integrated energy system (IES) optimal scheduling under the comprehensive flexible operation mode of pumping storage is considered. This system is conducive to the promotion of the accommodation of wind and solar energy and can meet the water, electricity and heat needs of coastal areas far away from the energy center. In this study, the joint dispatch between double pumped storage power stations is used to accommodate wind and solar energy better and smooth their fluctuations on the grid. Through the scheduling of water between the high and low reservoirs of double pumped storage power stations and the reservoir of the seawater desalination plant, the impact of storage capacity constraints on pumped storage power plants is reduced. Moreover, the objective function to build the IES optimization scheduling model is to achieve minimum economic cost. The results reveal that the integrated energy system accommodates all wind energy and solar energy. As such, the system increases the average working time of the pumped storage unit by 1.9 hours and reduces the economic cost by 31.50%. Based on the simulation results, the model can enhance the accommodation capability of wind energy and solar energy and improve the system economy.

Evaluation of low energy consumption control for seawater desalination on Penghu Island

In fact, current water supplies due to natural constraints or lack of infrastructure (or both) cannot be provided in a sustainable manner for all increasing and competing uses (e.g. residential, industrial, agricultural). While promoting Penghu's low-carbon islands, in a water-scarce environment, it is the motivation of this research to take into account the development of water resources and lower energy consumption costs. The seawater desalination plant water production technology is improved, the cost of water production is reduced. This research uses a genetic algorithm (GA) to optimize the recovery rate to solve the minimum Specific energy consumption (SEC) value, and then, according to the required water production, the optimal flow rate of raw seawater of the high-pressure pump is obtained, so as to minimize the energy consumption of the reverse osmosis (RO) system. The energy recovery device has a great effect on reducing the energy consumption of the RO system, and it can be seen from the results that the higher efficiency does greatly reduce the energy consumption of the SEC and water production under the different energy recovery device efficiency. Calculated using genetic algorithms, and the SEC is 3.275 and the recovery rate is 45.1%, and the water production energy consumption is 2.35 kWh/m3. Scheme B changed the efficiency of the energy recovery unit to 97.22%, resulting in a SEC of 1.819 and a recovery rate of 25.3%, and a water production energy consumption of 1.31 kWh/m3. Finally, challenges and research gaps are also proposed.

Assessment of brine disposal from Zliten desalination plant in marine environment

Desalination plants cause environmental pollution of local effects. Disposal of desalination effluents is considered as a serious environmental dilemma. The concentration of brine varies from 50 to 75 g/L and has a much higher density than seawater and consequently tends to fall on the seafloor near the brine outfall outlet (plume effect), therefore, creating a very salty layer that can have a negative impacts on the flora and the marine life and any related human activities. In this work, we present a case study on the environmental impacts of the effluents from the MSF seawater desalination plant into a coastal and marine ecosystem of Zliten-Libya. Samples were collected from the reject channel and therefore many parameters were measured such as PH, Temperature, Salinity, Conductivity and other parameters related to seawater and produced water have been investigated too. The results showed that the pH is slightly lower than the seawater; the values range from 6.1 to 7.8. The salinity of brine discharge was found 57113 ppm compared with 35000 ppm for the seawater. The TDS of brine discharge registered 56700mg/l in comparison with 32000 mg/l for seawater, Reject brines were around 10-14°C higher than the ambient seawater temperature, which causes a negative impact on marine ecosystems.