An advanced method for sea water chemical treatment in MSFD plants

Desulphation new applications: Doha East (Kuwait) and Gela (Italy) desalination plants

Thermal performance of seawater desalination systems

Economical evaluation of Alkhobar Phase two 50 MIGPD at three different mode of operations

The effect of increased top brine temperature on the performance and design of OT-MSF using a case study

Simulation of multistage flash desalination process

This work focuses on a multiple effect desalination system with thermal vapor compressor (MED-TVC) operating at a top brine temperature (TBT) of 85°C which is significantly above the common operation temperatures of conventional MED-TVC systems, limited to a range below 70°C mainly due to scale risk. Such increase in TBT would enhance the production and system economics. A pilot plant installed at the Desalination Technologies Research Institute (DTRI) of the Saline Water Conversion Corporation (SWCC) in Jubail, Saudi Arabia was operated at the TBT of 85°C over a 5-month test period. Visual inspection of tube bundles after the test, in conjunction with chemical scale analysis showed that scaling was limited to a soft thin film scale, which was easily removed by flushing with water, which confirmed a low fouling potential analyzed from operation data. Techno-economic analysis of the MED-TVC system operating at a TBT of 85°C, indicated up to 34% reduction in steam consumption and up to 16% reduction in the levelized cost of water (LCOW), when compared with a MED-TVC unit operating at a conventional TBT of 65°C. Accordingly, the high temperature MED-TVC systems operating at a TBT of 85°C can be considered as a financially competitive and technologically reliable desalination option for the Gulf area which has challenging seawater characteristics.

Solar energy is the most suitable among all renewable energy options for competing with fossil fuels in desalination due to its ability to utilize both heat and power for the process. In this study, the Parabolic Trough Solar Collector (PTSC) for powering a Single Stage Flash (SSF) desalination unit was proposed for Basrah city climate, Iraq. The desalination system comprises two directly coupled sub-systems: the PTSC and the SSF desalination unit. The preheated feed brine water coming from condenser was used as a Heat Transfer Fluid (HTF) for PTSC, which gets heated to a desired temperature referred to as the Top Brine Temperature (TBT). The numerical simulations were performed via EBSILON professional 16.02 (2022) software. The effects of TBT, mass flowrate of feed brine water to get the desired TBT, solar collector area, and vacuum pressure inside flash chamber on the performance of the desalination system was studied. A major finding of the current study can be summarized as follows: The collector efficiency is enhanced eventually as TBT increases. The maximum values of distillate water in June are around 5.5, 4.56, 3.69, 2.75 and 1.85 kg/h for 12.408, 10.434, 8.3472, 6.26, and 4.1736 m² collector area respectively, when TBT 107 °C and vacuum pressure 40 kPa. For 1.598 m² collector area, the total distillate in the 1st of June amounted to 7.9 kg, with an average production rate of around 0.7 kg/h. The solar SSF system's productivity per solar collector unit area at 20 kPa, 15 kPa, and 10 kPa vacuum pressures was 4.7 kg/day/m², 5.3 kg/day/m², and 6.25 kg/day/m², respectively. The average Performance Ratio (PR) values are determined to be 0.694, 0.577, and 0.491 for 10 kPa, 15 kPa, and 20 kPa, respectively. These results are very acceptable when compared with an existing literature.

Viability of integrating forward osmosis (FO) as pretreatment for existing MSF desalting unit

Mathematical modeling of the multiple effect evaporation (MEE) desalination process has been carried out to determine the effects of the important design and operating variables on the parameters controlling the cost of producing fresh water. The model assumes the practical case of constant heat transfer areas for both the evaporators and feed preheaters in all effects. In addition, the model considered the impact of the vapor leak in the venting system, the variation in thermodynamic losses from one effect to another, the dependence of the physical properties of water on salinity and temperature, and the influence of noncondensable gases on the heat transfer coefficients in the evaporators and the feed preheaters. The modified fixed-point iterative procedure is used to solve the large number of highly nonlinear equations describing the MEE desalting system. The algorithm consists of 10 calculation blocks and 6 logical blocks. The algorithm is implemented using L-A-S computer aided language. Results show that the heat transfer coefficients increase with the boiling temperature. Also, the heat transfer coefficient in the evaporator is always higher than that in the feed preheater at the same boiling temperature. The plant thermal performance ratio is nearly independent of the top brine temperature and strongly related to the number of effects. The specific heat transfer area increases by raising the number of effects and reducing the top brine temperature. The effect of the top brine temperature on the specific heat transfer area is more pronounced with a larger number of effects. The required specific heat transfer areas at a top brine temperature of 100°C are 30.3% and 26% of that required at 60°C when the number of effects are 6 and 12, respectively. The specific flow rate of cooling water is nearly constant at different values of top brine temperature and tapers off at a high rate as the number of effects is increased. Two correlations are developed to relate the heat transfer coefficients in the preheater and the evaporator to the boiling temperature. Design correlations are also developed to describe variations in the plant thermal performance, the specific heat transfer area, and the specific flow rate of cooling water in terms of the top brine temperature and the number of effects.

Techno-economic analysis of hybrid high performance MSF desalination plant with NF membrane

Improved productivity of the MSF (multi-stage flashing) desalination plant by increasing the TBT (top brine temperature)

The paper describes the application of fuzzy algorithms to the control of top brine temperature (TBT) of multi-stage flash (MSF) seawater desalination plants. A linearized model of a six inputs and six outputs 18-stage MSF plant is considered in this study. The transfer function matrix of this model is subjected to interaction between the loops. The design of fuzzy logic controller (FLC) for one of the important loops, namely the TBT loop is considered in detail. A set of fuzzy rules that make the controller look like a proportional-plus-derivative controller (PD-like FLC) is obtained and applied to a first order plus dead time approximation of the plant model. In order to improve the performance, an integration effect is added to the output of the PD-like FLC to produce PID-like FLC. A tuned version of the latter controller has been applied to the full plant model in its nonparametric form. The fuzzy controller was found to give good results compared to those obtained from the existing conventional controllers.

Solar power stands out as the prime choice among renewable energy sources for competing with fossil fuels in desalination due to its ability to utilize both heat and power for the process. This study introduces the concept of employing a parabolic trough solar collector (PTSC) to power a once-through multi-stage flash (OT-MSF) desalination unit in the climate of Basrah city, Iraq. The desalination system comprises two directly coupled sub-systems: the PTSC and the OT-MSF desalination unit. The preheated feed brine water coming from condenser was used as a heat transfer fluid (HTF) for PTSC, which gets heated from solar collector to a desired temperature referred to as the top brine temperature (TBT). Numerical simulations were conducted using EBSILON Professional 16.02 (2022) software to assess the system’s performance under seasonal variations in solar irradiance availability and varying values of TBT. The effects of solar irradiance availability, TBT, mass flowrate of feed brine water, last stage temperature on the economic cost of distillate water was studied. A major finding of the current study can be summarized as follows: The highest distillate output, observed in June, reaches 159.53 kg/sec with TWC of 1.79 $/m3, while the lowest, observed in January, is 83.42 kg/sec and TWC of 2.02 $/m3, when TBT of 112 ˚C and the last stage temperature of 40 ˚C. With a total solar collector area of 130,000 m2, the normalized yield of the distilled water per square meter per day ranges from 55.44 to 106 kg/m2/day. Increasing distillate production and decreasing total water cost (TWC) are observed when the final stage temperature is adjusted to 30°C instead of 40°C. In January, distillate output reaches 93.7 kg/sec, compared to 179 kg/sec in June. While, TWC is recorded at 1.97 $/m3 in January and 1.76 $/m3 in June. Also, it has been observed that with the increment of TBT from 90 °C to 112 °C, the production of distillate water rises from 112.87 kg/s to 161.32 kg/s, while maintaining a constant feed brine water flow rate of 1321.62 kg/s. These findings are very acceptable when compared with an existing literature.

Influence of operating temperature range on the performance of multi-effect desalination (MED) plant

Additive scale control optimization and operation modes