Multi-effect Desalination Plant Research Articles

열압축기를 채용한 다중효용 담수설비의 운전특성에 관한 연구(1보)

Abstract ： The core design technology for the multi-effect desalination plant using the thermo compressor (MED-TVC) was investigated by the performance test of multi effect desalination plant in this paper. The final G.O.R (gain of output ratio) of MED-TVC type desalination plant is strongly affected by the performance of thermo-vapor compressor. The present experiments for the desalinating capacity and G.O.R were obtained for the range of the motive steam pressure, 266.0, 250.0, 230.0 and 200.0 kPa. And as a practical problem, to investigate the influence of the sea water temperature to the G.O.R, the inlet steam temperature of the suction water vapor was changed in the range of 311.2~324.2 K in the present experiment. Through the experiments, the maximum value of G.O.R was 8.5 at the condition of the motive steam pressure, 136.0 kPa and the minimum value of G.O.R was 8.1 at the condition of the motive steam pressure, 266.0 kPa. And it was confirmed that the range of desalination capacity was 355.2~264.0 ton/day in the normal operation condition.

Low grade heat utilisation for seawater desalination by the HTTF process

To improve heat transfer efficiency, Horizontal Tube Thin Film (HTTF) evaporators are being used in multieffect desalination plants. These plants require less pumping energy than thermal-based desalination plants. To generate the design data, experimental studies were carried out in a single-tube HTTF experimental setup, and heat transfer correlations were developed at BARC. The experimental findings and results are presented and discussed in this paper.

Steady- and transient-state analysis of a multi-effect mechanical vapour compression desalination plant

A model is presented to study the steady and transient state responses of the system during startup and sudden load changes/disturbances of the Multi-effect Mechanical Vapour Compression (ME-MVC) desalination system. Some of the main dependent parameters like the compressor work, and the mass flow rate of distilled water against the independent parameters like the evaporation side pressure and the water inlet temperature have been studied. Also, the Performance Ratio (PR) and the heat transfer area dependency on the number of effects and Top Brine Temperature (TBT) have been studied. The material and energy balance equations for the feed, product and brine flow for each effect have been written and then solved simultaneously to obtain the time-dependent parameters under various transients. The effects of a step change in feed flow and temperature with respect to brine salinity and product flow rate, etc. have also been studied.

전산해석을 통한 열증기압축기 설계와 실험적 검증

A thermal vapor compressor in which the subsonic/supersonic flow appears simultaneously, has been accurately designed through the CFD analysis for the various shape parameters such as the primary nozzle shape, converging duct shape, mixing tube diameter, and so on. The performance of the developed thermal vapor compressor has been experimentally verified to be installed in a Multi Effect Desalination(MED) plant as an important element. In this paper, the effects of each parameter are discussed on the basis of CFD results and the experimental results for various boundary conditions(motive pressure, suction pressure, and discharge pressure) are presented in compared with CFD results. The two results show a good agreement with each other within 2 % accuracy with regard to the entrainment ratio.

Advanced MED process for most economical sea water desalination

The low temperature horizontal tube multi-effect desalination (MED) process is thermodynamically the most efficient of all thermal distillation processes. A comprehensive multi-disciplinary development and design approach resulted in prevention of corrosion and scale formation on the plant’s heat transfer surfaces. It also allows the successful and most economical use of aluminum alloys for heat transfer tubes, as well as carbon steel epoxy coated shells for the evaporator body. The ability to use economically low grade heat, such as waste heat, exhaust steam from power station turbines as the primary heat source for MED, yields very low specific energy costs for sea water desalination. Recent developments of very economical low temperature deep pool nuclear heat reactors, when acting as the primary energy source for large MED plants, yield very low specific desalination energy costs. The combination of economical specific MED plant costs with low energy cost, together with the inherent durability of low temperature MED avoiding the necessity of comprehensive sea water pretreatment (such as with RO plants) make the MED process one of the best candidates for safe and durable large capacity economical desalination options. This paper describes the design principles and various energy considerations that result in this uniquely economical MED process and plant. It also provides an overview of various cases of waste heat utilization, and cogeneration MED plants operating for many years.

Design and application of thermal vapor compressor for multi-effect desalination plant

A thermal vapor compressor (TVC) in which the subsonic/supersonic flow appears simultaneously, has been accurately designed through the CFD analysis for the various shape parameters such as the primary nozzle shape, converging duct shape, mixing tube diameter, and so on. The performance of the developed TVD has been experimentally verified to be installed in a multi-effect desalination (MED) pilot plant. In this paper, the experimental results for various boundary conditions (motive pressure, suction pressure, and discharge pressure) are presented in comparing with CFD results. The two results show a good agreement with each other within 3.5% accuracy with regard to the entrainment ratio.

Fuel economics: A comparative study of dual-purpose power and desalination plants in the WED grid based on a constant heat value of water

A novel concept of a constant heat value of water was proposed in [1,2]. The idea is simply that power and desalination plants produce two products quite different from each other. If they could be measured in similar units of measurement, the analysis of operation and performance of the plants can be made easy with respect to fuel utilization in actual operation. It was proposed that a constant heat value be assigned to the potable water produced by desalination. The suggested heat value was the theoretical minimum heat required [5] under ideal operating conditions in a 100 multi-effect desalination plant [1] to produce one unit of potable water. Based on the above hypotheses, a sample performance analysis has been carried out for the 4 power and desalination stations, i.e STPS, UAN(W) units 1 to 8, UAN (E) units 1 – 4, and TAWEELAH (A), in the Abu Dhabi, WED grid, and a comparative study has been made on the water and power production for a period of 12 months for the year 1990, on fuel efficiencies, share of fuel used and the specific fuel consumption and costs for water and power production respectively. The results have been tabulated, presented graphically, discussed, and fuel economics analyzed.

Coupling of a power plant with a low temperature Multi-effect desalination plant

The low-temperature heat discarded by a large power plant can produce large quantities of desalted seawater at low cost. This paper describes a system in which a horizontal tube multi-effect (HTME) desalination process is coupled to a large power plant (either nuclear or non-nuclear) in such a manner as not to interfere with the power cycle. The resulting product water is produced at a cost approximating present prices of water sold by water companies.

Projet d'usihe de dessalement a multiple-effet a surface d'echange en matiere plastique

Can we imagine conceiving and running a Multi-effect desalination plant using heat transfer surface 30 to 50 times less expensive than conventionnal copper-alloy or titanium surface? Tests made at Nuclear Study Center of Grenoble during several years gave the proof that this was possible by using very thin plastic surfaces (50 to 100 μ) with whichglobal heat transfer coefficient comparable with metallic tubes can be reached. Our mind is that among all the attempts of new distillation technologies applied to desalination since ten years ago this one proves to be of the upmost interest. It must widen desalination market estate and interest in the desalination applicant countries above the opinion of Consultant Engineers whose a through technical reform is often uncomfortable.