Desalination energy recovery

They are applied to various processes, such as the energy recovery sections of crystallisation and desalination plants. 

Figure 331 Process flow diagram of a seawater RO membrane plant integrated with a hydraulic energy recovery turbine. Source Desalination 82 (1991) 31.

R. Singh, S.V. Cabibbo, Hydraulic turbine energy recovery — R.O. system. Desalination 32 (1980) 281-296. 

Kim, Y., Kang, M.G., Lee, S. et al. (2013) Reduction of energy consumption in seawater reverse osmosis desalination pilot plant by using energy recovery devices. Desalination and Water Treatment, 51 (4-6), 766-771. doi 10.1080/19443994.2012.705549... 

Mohamed ES, Papadakis G, Mathioulakis E and Belessiotis V (2006), An experimental comparative study of the technical and economic performance of a small reverse osmosis desalination system equipped with an hydraulic energy recovery system , Desalination, 194,239-250. 

Compared to the classic work of the twentieth century, various new technologies are considered for CDI today, such as the inclusion of ion-exchange thin membrane barriers in front of the electrodes, - optimized operational modes such as stop-flow operation during ion release, salt release at reversed voltage, constant-current operation, " energy recovery from the desalination/release cycle, " and flow-through electrodes where the water is directed head-on through the electrodes. ... 

Recent progress on high-pressure-high-rejection spiral wound (SW) RO elements, combined with proven and innovative energy recovery and pumping devices, has opened new possibUities to reduce investment and operating cost. The progress of RO seawater desalination from a point of view of water recovery is shown in Table 1.4 (Moch, 2000). 

Seawater RO desalination plants typically consist of the following key components intake pretreatment system filter effluent transfer pumps high-pressure pumps, piping, and RO membrane system energy recovery system and permeate conditioning (posttieatment) facilities. 

An example of a two-pass/two-stage SWRO plant is the 110,000-m /day Point Lisas facihty in Trinidad. This plant produces high-quality desalinated seawater of TDS concentration of 85 mg/L or less, which is predominantly used for industrial applications. The first pass of the Point Lisas SWRO system consists of six two-stage RO units. Each of the first-stage RO trains uses SWRO membranes and is coupled with energy recovery devices. The second-stage trains of the first pass are equipped with brackish water RO elements. 

As previously mentioned, the key SWRO project construction expenditures are associated with building the plant intake, the pretreatment system, procurement and installation of the plant pumps and piping, the SWRO membranes and pressure vessels, the energy recovery system, the water posttreatment facilities, and the concentrate disposal system. It is difficult to compare the investment and construction costs of existing desalination projects because projects may differ significantiy in one or more of the cost-related parameters listed above. Based on previous experience, however, it can be estimated, for example, that the seawater pretreatment costs are in the range of 6-8 US cents/m and the costs of water conditioning and boron and chloride removal are between 4 and 8 US cents/m. ... 

Liberman, B. (2002). The importance of energy recovery devices in reverse osmosis desahnation. In The Future of Desalination in Texas, Vol. 2, Technical Papers, Case Studies Desahnation Technology Resources (Report No. 363). Texas Water Development Board, Austin, Texas. 

ViUa Sallangos, O. L. (2004). Operating experience of the Dhekelia seawater desalination plant using an innovative energy recovery system. In Proceedings Euromed 2004, Morocco, pp. 17-19. 

Bromley and co-workers (36) have calculated the minimal energy of separation of water from seawater containing 3.45 wt % salt, at 25°C, to be 2.55 kj/(kg fresh water) for the case of 2ero fresh water recovery (infinitesimal concentration change) and 2.91 kj/(kg fresh water) for the case of 25% fresh water recovery. is, however, severalfold smaller than the energy necessary for water desalination ia practice. 

Module performance and energy consumption were estimated in the case for the desalination of U.2% salinity seawater under high pressure of 75 Kg/cm2c at different recovery ratios. The results are shown in Table 4. 

Several schemes have been put forth in the past for desalinization by use of electrolysis. They had been discarded because of the large amounts of energy required. The idea was resurrected in anticipation of much more efficient recovery of energy through the use of fuel cells. 

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