Multi-stage Flash Desalination Plant Research Articles

Thermo-Economic Analysis of Gas Turbine Combined Multistage Flash (MSF) Desalination Cycle

Over the past few decades, the growth of the earth’s population has increasingly contributed to global warming, and increased demand for fresh water on top of a need for a greater power supply. This paper will analyze the integration of a combined- gas turbine with intercooler and a multi-stage flash (MSF) desalination plant for the simultaneous generation of electricity and supply of water and improved performance. The paper will also examine the calculation of the production cost and the capital cost of the MSF desalination plant. The thermo-economic analysis of the study was conducted using the IPSEpro software system. Also, exergy losses of the gas turbine and MSF desalination unit were also calculated. The desalination plant uses the exhaust gases from the gas turbine, as a form of thermal energy, and discharges to feed the seawater heater. A portion of the desalinated water is used to cool the compressed air in the intercooler heat exchanger. Results indicate the improvement in the gas turbine’s performance when desalinated water is used for the intercooler between compressor stages, as the power output increased by 59% over the the simple gas cycle and found decrease with an increase in the ambient temperature. The desalinated water cost was calculated to be $1.7 per cubic meter after determining the optimal configuration and operating conditions. A decrease in steam cost by 36% was observed when the waste heat from the gas turbine was used as the source of thermal energy. Part of this reduction can be explained by the observation that the desalination plant’s pumps consume part of the power generated by the gas turbine.

Control of Bromate Formation in Desalinated Seawater Production and Transmission with Ammoniation

Bromate is a potentially carcinogenic disinfection by-product of potential concern in desalinated waters, where bromide derived from seawater can be converted to bromate by the oxidising species used for disinfection. Historically, it has been difficult to maintain complete adherence to national standards of no more than 10 ppb for bromate at all locations served with desalinated seawater by the Saline Water Conversion Corporation (SWCC) in the Kingdom of Saudi Arabia. In this full-scale study, the addition of 100–200 ppb of ammonia to the produced water of a Multi-Stage Flash Desalination plant effectively controlled the formation of bromate in the transmission system supplying inland centres in the Makkah Province of the Kingdom of Saudi Arabia (Arafa, Taif) on a time scale sufficient for the distribution of water to the consumer, even when the bromide content of the produced water was artificially enhanced (up to 132 ppb) via the addition of seawater.

CO2 hydrogenation for geothermal energy storage through synthetic natural gas production and byproduct of refrigeration and freshwater using solid oxide electrolyzer cell (SOEC) and methanation reactor; Techno-economic evaluation and multi-objective optimization

A multi-generation geothermal-based energy system is proposed to convert geothermal renewable power into fuel gas and other valuable products such as electricity, cooling, and freshwater. The system is analyzed and optimized from a thermo-economic perspective. This system is constituted of a flash-binary geothermal power plant integrated into an Organic Rankine Cycle, a double-effect Li/Br absorption refrigeration cycle, a multi-stage flash desalination plant (MSF), and a solid oxide electrolyzer cell (SOEC) combined with a Sabatier methanation reactor. The steam leaving the steam turbine are utilized by the SOEC to generate hydrogen, which is used in the Sabatier reactor to hydrogenate CO2 to produce methane. Cooling and Freshwater are respectively produced by the refrigeration cycle and MSF plant that are driven by the steam extracted from the intermediate stages of the steam turbine. The system can produce 22.9 g/s gas fuel with a lower heating value (LHV) of 28453 kJ/kg, of which 53% is methane, 554.4 kW net power, 3715 kW cooling, and 41.35 kg/s freshwater. The SOEC produces hydrogen with a rate of 6.52 g/s; the power demanded to generate this amount of hydrogen is 884.47 kW. The system’s payback period is 7.3 years (regarding the tax). According to the optimization results, compared to baseline design conditions, the payback period and LHV of the generated fuel respectively decline by 18.7% and 35%, and the net output power enhances by 88% at optimum mode when power and payback period are objective functions.

Techno-economic assessment of forward osmosis as a pretreatment process for mitigation of scaling in multi-stage flash seawater desalination process

Thermal desalination processes suffer from the formation of scalants on the heat exchangers of the evaporator unit which negatively affect the process efficiency. This study evaluated the technical and economic feasibility of a pilot-scale forward osmosis (FO) process for the pretreatment of seawater to remove scaling ions before the multi-stage flash (MSF) process. A commercial hollow fiber FO membrane module was used in the pilot plant. The FO pilot plant used real seawater as feed solution and real MSF brine as draw solution. A maximum recovery rate of 27.7 % was achieved using a pressure gradient of 1.0 bar with the feed solution flowing through the membrane bore side and the draw solution flowing through the shell side with a temperature of 40 °C for both feed and draw streams. The FO membrane showed high rejection for scaling ions, where the rejection rate was almost 99 %, 96 %, and 92 % for sulfate, calcium, and magnesium, respectively. The specific power consumption of the FO process was about 0.01 kWh/m3. It was found that the water production cost for the FO process was almost 0.48 $/m3. The sensitivity analysis shows that the water production cost is highly sensitive to the water flux, especially at the lower range of water flux and high membrane cost. FO pretreatment provides a promising and economical solution for mitigating the scaling issue in MSF desalination plants.

Component-based, dynamic simulation of a novel once through multistage flash (MSF-OT) solar thermal desalination plant

The present study further investigates a novel concentrating solar thermal desalination process using a dual tank system, which addresses one of the biggest challenges in wider adoption of solar applications: 24-h dispatching of solar energy. Direct use of solar energy only during daily sun hours might be acceptable on a small scale, but not economically viable on a larger scale. In this study, a complete once through multi-stage flash (MSF-OT) desalination plant powered by solar thermal energy was modeled using the TRNSYS modeling environment. The model results are in good agreement with previous general studies, but the novelty here is development and use of a component-based, dynamic simulation model of the entire desalination plant, which more accurately represents real situations, and allows parametric analyses of important design variables such as the number of stages, top brine temperature, operating pressures, and solar concentrator area. Key indicators were used to evaluate this novel concept, which included the performance ratio, PR (the ratio of the total energy required to evaporate the brine to the total solar energy gained), the recovery ratio, RR (the relative amount of distillate extracted from the feed water), the specific mass feed water flow, SMF (the ratio of the feed water mass to the mass of the produced distillate water), as well as a detailed economic analysis. System improvements relative to previous studies included use of series/parallel configuration of the solar concentrator array and improved thermodynamic modeling of vacuum pressures in flashing tanks. Results of this study showed that the size of the solar concentrator array can be reduced by 54 % relative to previous studies. The average daily values of the performance ratio (PR). the recovery ratio (RR), and the specific mass feed water flow (SMF) were approximately15.2, 13.8 %, and 7.25. Finally, based on a detailed economic analysis, it was found that the water price could be reduced by nearly 15 % to $2.33/m3.

Use of orange peel extract as an inhibitor of stainless steel corrosion during acid washing in a multistage flash desalination plant

Environmentally friendly and cost-effective inhibitors based on orange peel extract (OPE) have been developed for potential applications in ejector tubes of a multistage desalination plant during the acid cleaning process. After conducting tests under both static and hydrodynamic circumstances, it was determined that the inhibitor formulation was effective against corrosion of stainless steel (SS) in 1 M HCl solution at 30 °C under the conditions tested. Electrochemical methods were used along with electron microscopy to collect information on the corrosion inhibition efficiency of the extract. Experiments were conducted for 1, 2, 3, 4, 6, 12, and 24 h, and the performance of OPE was compared to that of a commercial acid corrosion inhibitor to determine which performed better. The results revealed that OPE demonstrated outstanding corrosion inhibition performance compared to the commercial acid corrosion inhibitor. With remarkable inhibition efficacy for up to 24 h under both static and dynamic settings, 0.4% of OPE displayed typical mixed-type corrosion inhibitor behavior in the tested environment. All of the procedures that were used produced results that were in good agreement. Due to the synergistic action between the two compounds, the corrosion inhibition of OPE on SS was improved in 1 M HCl in the presence of iodide ions. In the absence of KI, OPE was found to inhibit SS corrosion at a concentration-dependent rate, with the concentration of OPE being the most significant factor. A study of the adsorption of OPE onto a SS surface revealed that the Langmuir adsorption isotherm controls the process. Based on the quantity of free energy of adsorption observed, it was determined that there is physical contact between the OPE and the surface of SS in this experiment. It was possible to identify the most effective phytochemicals for corrosion inhibition based on the findings of quantum chemical calculations, which were subsequently evaluated in the laboratory.Graphical abstract

Design of trigeneration plant for electricity freshwater production, and district heating: A case study Periwinkle Lifestyle Estate, Lagos Nigeria

This study proposes a design of a trigeneration plant for the usage of Periwinkle Lifestyle Estate in Lagos State Nigeria. The proposed system would provide electricity, heating and freshwater requirements for residential buildings from a renewable energy source. Concentrated photovoltaic solar thermal (CPV/T) collector is used to generate the electricity and provides the required amount of thermal energy to the multistage flash desalination plant and Kalina cycle due to its high electrical and thermal effectiveness. The EES is used to model the tri-generation system by solving the governing equations with an interconnected structure, while TRNSYS and HOMER software was also used to collect the solar data for the case study area. The combined trigeneration structure can produce 0.6412 kg/s of freshwater, 1520.25 kW of electricity generation, and 91.57 kW of heat required for the district heating application, for the usage of Periwinkle lifestyle estate Lagos State Nigeria. The designed system can serve as an alternative to producing high-quality freshwater for drinking and irrigation, reliable and steady electricity and heating services during the winter season, without pollution. • A trigeneration system using CPVT is presented. • The effect of ammonia concentration on the system is analyzed. • The combined trigeneration structure can produce 0.6412 kg/s of freshwater, 1520.25 kW of electricity generation. • The proposed system can meet the electricity, heating and fresh water demands of case study city.

Machine learning-driven energy management of a hybrid nuclear-wind-solar-desalination plant

The ongoing energy transition and incoming water scarcity crisis demand coordinated research to ensure a fossil-free future for humankind. Aiming to increase energy efficiency, reduce curtailment and decarbonize water production, this paper proposes a novel energy management system (EMS) for a hybrid plant compound by a small modular nuclear reactor acting as cogeneration unit, a wind and solar farms as generators. Additionally reverse osmosis and multi-stage flash desalination plants are included as demand responsive units along with a freshwater storage. Mixed integer linear programming (MILP) is employed to formulate this stochastic optimization problem, where piecewise linear functions define operational costs and efficiencies of SMR and desalination motivating energy efficiency and safety. Renewable availability point forecasts are obtained with physics informed machine learning models whose error is characterised by fitting the predictor's residuals to different statistical distributions following an unsupervised methodology. The suitability of the EMS is addressed in two study cases, one exploring the flexibility exploitation of the algorithm and another proving its suitability for real-time implementation. The dispatcher manages to keep unaltered the SMR's core reaction while satisfying both electrical and water demand in different renewable availability regimes by fully exploiting sector coupling flexibility. Simultaneously, renewable curtailment is kept to a minimum.

Experimental Validation of a Solar Powered Multistage Flash Desalination Unit with Alternate Storage Tanks

The fossil fuels that power conventional desalination systems cause substantial environmental impact. Solar desalination can satisfy critical water needs with only a minimal contribution to global warming. The current work presents an attractive new design suitable for regions with limited water resources and high solar radiation rates. This work is an experimental study of a newly designed, solar-powered, multi-stage flash (MSF) desalination plant. The design could address the need to increase the limited water resources in solar energy-rich areas. The prototype consists of a solar collector, an MSF unit, and a novel dual thermal storage tank design. In this prototype, preheated brine is directly heated by circulation through the solar collector. Two tanks serve the MSF unit; one tank feeds the MSF unit while the other receives the preheated feed water. The two tanks alternate roles every 24 h. The study was conducted in Taif, Saudi Arabia, throughout the month of September 2020. The results of the experiment showed that 1.92 square meters of solar collector area is needed for an average daily production of 19.7 kg of fresh water, at a cost of approximately $0.015 per liter.

Energy, exergy, exergo-economic and exergo-environmental analyses of solar based hydrogen generation system

The present study focuses on the energy, exergy, exergo-economic, and exergo-environmental analyses of the solar-assisted multi-generation system. The multi-generation system consists of parabolic trough solar collector, regenerative power plant, double-effect absorption chiller system, proton exchange membrane electrolyzer, and multi-stage flash desalination plant. In the regenerative power plant, liquid petroleum gas (LPG) based boiler is implemented. The propane (C3H8) is used as the fuel in the boiler combustion chamber. The thermal and exergetic efficiencies of the power cycle are observed to be 41.08% and 23.26%, respectively. The electrical power of 1.384 MW is produced by the low-pressure turbine. Whereas, the thermal COP and exergetic COP are observed and maintained in the range of 1.28 to 0.22, respectively. The liquid hydrogen is produced by the PEM electrolyzer with the thermal and exergetic efficiencies of 60.83% and 64.65%, respectively. Furthermore, the exergo-economics and exergo-environmental analyses have also been conducted and all the parameters have been analyzed and concluded through graphs and tables.

Entropy generation in multi-stage flash desalination plants

A second-law analysis of two types of MSF desalination plants (once-through OT and with heat rejection section HR) is conducted. Fixing the number of stages to 20, the HR configuration is found to present clearly less entropy generation but more specific area than the OT configuration. The detailed investigation showed that heat transfer is responsible of more than 65% of the irreversibility occurring in a stage. The 30% reduction of the entropy generation number when passing from OT to HR is totally due to the reduction of the heat-transfer irreversibility. The variation of the number of stages for OT configuration has no effect on the entropy generation. Besides, we noted that beyond 10 stages the specific area is not expected to vary noticeably. For the HR configuration, there is a continuous decrease of the entropy generation number accompanied by a continuous increase of the specific area. The comparison between the two plants showed that HR is not necessarily better than OT. The decision of which of them is the most competent depends on the number of stages and on the relative importance we attach to the irreversibility and to the specific area.

Exergoenvironmental analysis and evaluation of coupling MSF, MED and RO desalination plants with a combined cycle plant

In this paper, freshwater production through multi-effect desalination (MED), multistage flash (MSF), reverse osmosis (RO), hybrid (MED-RO), and hybrid (MSF-RO) units have been investigated based on environmental impacts associated with life cycle assessment (LCA) modelling tool and exergoenvironmental analysis. The integration of Qom combined cycle as a real case study with selected desalination plants has been studied. In this regard, thermodynamic simulation has been performed in computer code with high accuracy. Furthermore, computer code has been developed to perform exergy, exergoeconomic, and exergoenvironmental analyses. Results show; the environmental impact rate associated with the integrated combined cycle with the MED unit decreased by 23% compared to the stand-alone power plant. Also, in the integration of combined cycle with MSF, RO, MED-RO, and MSF-RO, it has been found that 25%, 60%, 27%, and 25% decrease can be obtained in the environmental impact rates, respectively.

Corrosion inhibition effect of a benzimidazole derivative on heat exchanger tubing materials during acid cleaning of multistage flash desalination plants

A benzimidazole derivative, 2-(2-bromophenyl)-1-methyl-1H-benzimidazole (2BPB) has been studied as a corrosion inhibitor for Cu-Ni 70/30 and 90/10 alloys in 1 mol/dm3 HCl solution at low and high temperatures using the weight loss, electrochemical (potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), & cyclic voltammetry (CV)), and surface characterization (scanning electron microscopy (SEM) & Fourier-transform infrared spectroscopy (FTIR)) techniques. The effect of immersion time (up to 72 h) and addition of iodide ions on the inhibition efficiency of 2BPB have also been investigated. At low temperature, 1.0 g/L 2BPB inhibits Cu-Ni 70/30 and 90/10 alloys by 88.9 ± 4.8% and 57.5 ± 1.3%, respectively. The performance of 2BPB improves with increase in immersion time and addition of iodide ions but slightly depreciates with rise in temperature. 2BPB acts as a mixed type corrosion inhibitor and adsorbs on the alloys surfaces through physical adsorption mechanism. SEM and FTIR results confirm the adsorption of 2BPB on the alloys surfaces. 2BPB is a potential low toxic candidate for the formulation of acid corrosion inhibitor for Cu-Ni alloys.

Simulation of Multi-Stage Flash with Brine Circulating Desalination Plant

Multi-stage flash (MSF) desalination is the main process to solve the problem of limited freshwater resources in the world. This work describes the developed steady-state mathematical model for analysing and evaluating the performance of Multistage flashing with brine circulation desalination process (MSF-BC). It is based on the laws of energy balance, material balance, and heat transfer equations with physical properties correlations equations. The nonlinear equations are linearized and arranged into a tridiagonal matrix form. The model solution is obtained by a computer code written by MATLAB program software. It can predict the productivity of the plant with temperature profiles and flow rates for all stages in the unit. The model results were compared with some previous results presented in literature. The comparison shows good agreement with these available data. An MSF desalination plant in Ayoun Mousa, Egypt of capacity 5000 m 3 /day was presented as a case study.

Highly efficient corrosion inhibitor for C1020 carbon steel during acid cleaning in multistage flash (MSF) desalination plant

A new environmentally friendly and cost effective molecule, thiabendazole (TBZ), was evaluated as a potential acid corrosion inhibitor for a typical carbon steel (C1020 grade) used as construction material in MSF desalination plant using electrochemical and (weight loss) immersion techniques. Electrochemical measurements after 1, 4 and 8h immersion in 1.0M HCl at 25°C showed that TBZ is an excellent corrosion inhibitor for C1020 grade steel and its inhibition efficiency reaches ≈90% at 4mM concentration with no substantial increase at 10mM. In the presence of iodide ions, TBZ showed improved corrosion inhibition attaining inhibition efficiency of 94.3% with 4mM concentration after 4h of testing with no increase in inhibition efficiency after 8h. However, weight loss measurements indicate that the corrosion inhibition performance of TBZ, and TBZ in combination with KI decreased with immersion time up to 24h and temperature up to 60°C. SEM-EDX and ATR-IR spectroscopy confirm that the inhibition process was due to the formation of an adsorbed film that protects the steel surface against corrosive medium. DFT and Monte Carlo simulation results gave further molecular and atomic level insight on mechanism of interaction between the inhibitor and the steel surface.

Use of Nanoparticles for the Disinfection of Desalinated Water

When chemical disinfection is performed before or after desalination, a number of harmful compounds are formed. Thus, efforts have been directed toward developing alternative methods for water disinfection. In this study, seven nanoparticles (NPs) were evaluated for disinfecting water produced from reverse osmosis and multi-stage flash desalination plants. The tested NPs were silver, copper, silver-copper, zinc oxide, magnesium oxide, silicon dioxide, and carbon nanotubes. The antimicrobial activity of the NPs was investigated by batch studies in desalinated water samples spiked with E. coli, Enterobacter, Salmonella, and Enterococci. The Chick-Watson model was fitted to the inactivation data to evaluate the kinetic constant for each combination of NPs, water type, and indicator bacteria. The results indicated that silver and silver-copper NPs have the highest disinfection efficiency among the tested NPs. Among the bacteria, Enterobacter (strain TPC129) appears to be the most inactivated, while Enterococci (strain NCTC775) seems to be the least influenced by the NPs. Variations in the chemical characteristics of the tested water samples appeared to cause noticeable differences in the antibacterial efficacies of copper and magnesium oxide NPs, but not in those of the other NPs.

Fuel utilization of steam power cycles integrated with multi-stage flash (MSF) desalination plants

Fuel utilization of steam power cycles integrated with multi-stage flash (MSF) desalination plants

Novel multi-stage flash (MSF) desalination plant driven by parabolic trough collectors and a solar pond: A simulation study in UAE

This paper investigates a novel solar driven multi-stage flash (MSF) desalination plant in UAE. UAE achieved major progress in utilizing solar energy for power production. The desalination plant simulated in this work investigates the use of parabolic trough collectors (PTC) and a solar pond to completely satisfy the energy requirements for a multistage flash desalination. The plant is designed to be located in Sharjah, UAE; a region that receives a high level of solar radiation. The process was equipped with a fire tube boiler to satisfy energy requirements when the sunlight is not available. Aspen HYSYS V8.8 simulation software was used to conduct this study. The objective was to satisfy the water demand for a small community with a total population of around five thousand. The simulation aimed at producing 1880 m3/day of desalinated water, out of 40,000 m3/day of seawater processed. The results showed that two PTCs of a total aperture area of 3160 m2 can provide about 76% of the MSF energy requirements. The remaining part is provided by a solar pond of 4 meter depth and a surface area of 0.53 km2.

Performance test of a sea water multi-stage flash distillation plant: Case study

Multi-Stage-Flash (MSF) Distillation is a large scale sea water desalination plants that are widely used in Gulf area. Most installations of MSF plants are operated in cogeneration with a power plant. Also, MSF plants can be combined with other desalination technologies such as Nano filtration and Reverse osmosis (RO) in new installation. However, the new MSF plants are recommended, where large amounts of cheap or waste energy are available (e.g. conventional power plants). Also, the plant location is playing an important role for economic operation due to cold or hot weather conditions.The present study is applied on the seawater multi-stage flash (MSF) desalination plant that is currently under operation in Al-Khafji operations plant located in Saudi Arabia (KSA). The plant contains 20 evaporator stages at capacity of 600,000 gallon per day (GPD). The presented operating data has been collected during a visit of the plant. Theobjectiveis to presentfieldresults of this MSF plant operation in order to measure and evaluate the performance at 70% and 100% capacity during summer (case-1) and winter (case-2) operation. Then, the plant overall performance indicators are presented to compare between the studied two cases in terms of specific cooling water flowrates and performance ratio. Finally, the seasonal performance variation of the plant is included. The results showed that, for the same plant output, the main cooling water flow rates is decreased from 47.1% to 20.1% for case-1 and case-2 respectively, which in turns directly reduces the pumping power by the same ratio. Consequently, running the large scale thermal desalination MSF plant in cold regions is more economic than hot regions for pumping power energy saving considerations. This is to be considered in future large scale desalination plants.

Modelling and Simulation of Multistage Flash Desalination Plants

This study describes the mathematical model developed for evaluating the performance of multistage flash (MSF) desalination plants at steady state operation. The governing equations are linearized and are arranged in a tridiagonal matrix form. The solution of these equations are obtained by a computer code written in visual basic language with friendly user format developed for this purpose. This code can predict the plant productivity with profiles of temperatures and flow rates for all stages in the unit. The present results were compared with some previous results presented in literature, and with the design data of MSF plant existed in Benghazi city. The comparisons show good agreement with these available data.