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Water Reuse and Recycling
Published in Maulin P. Shah, Removal of Refractory Pollutants from Wastewater Treatment Plants, 2021
Khushboo Dasauni, Divya, Tapan K. Nailwal
For thermal desalination, if there is no steam, a temperature gradient is required. In this case, the temperature gradient in the ocean can be considered. In the ocean, temperature changes with depth. By rapidly evaporating hot water at low temperatures and condensing the resulting vapor with cold water, the available thermal gradient between warmer surface water and colder deep seawater is utilized. Today, cryogenic distillation is widely regarded as one of the promising methods for desalination. The low temperature thermal desalination (LTTD) process uses the temperature gradient between two bodies of water to evaporate hotter water at low pressure, and uses colder water to condense the resulting steam to obtain high-quality fresh water. The temperature gradient between the different layers of the ocean water column provides huge warm and cold reservoirs, which can be effectively used for power generation and desalination. The main components required by the LTTD plant are the evaporation chamber, condenser, pumps, and pipes to extract warm and cold water, and vacuum pump to maintain the pressure below the atmospheric pressure. One of the advantages of this method is that it can be implemented even when the temperature gradient between two bodies of water is about 8–10°C (Sistla et al., 2009).
Status of tidal energy system in India
Published in Journal of Marine Engineering & Technology, 2021
This energy is anyway less elevated than what is accessible in more northern and southern expansions. In 2000 NIOT Goa, prompted a programme to lead look at on improvements for making splendid clean drinking water and energy of the sea. The goal was to make 2–3 lakh litres for consistently freshwater utilising the Low Temperature Thermal Desalination progressed by 1 MW OTEC Power Plant (Ravindran and Raju 1997). All things considered, it was dropped because of challenges in the establishments. In 2010 Kalpasar Tidal Power Project at The Gulf of Khambhat was perceived as a promising site for tidal power time by UNDP Expert. On Jan 2011, the area of Gujarat broadcasted plans to show Asia’s first business scale tidal current power plant; the state government grasped the progression of a 50 MW meander in the Gulf of Kutch. Table 1 shows the Location keen Geographical condition for Tidal Power Station. None at the present time, anyway the India’s Ministry of New and Renewable Energy said on Feb 2011 that it might give cash related motivations to as much as 50 percent of the expenses for meanders wanting to demonstrate tidal impact. In 2014 Atlantis Energy proposed to present and make 50–200 MW Tidal stream based power plant in Gulf of Chambey (Barkin and Ferrandiz 2004; Barbarelli et al. 2014a; Barbarelli et al. 2014; Barbarelli et al. 2015).
Technology developments for the strategic Indian blue economy
Published in Marine Georesources & Geotechnology, 2019
N. Vedachalam, M. Ravindran, M. A. Atmanand
Over the past decade, the global desalination capacity has recorded an annual growth rate of about 2% (Water Supply Diversification Desalination, Water Research Foundation 2017). Subsequent to the experiences gained by NIOT in the development of a single-point moored barge-mounted Ocean Thermal Energy Conversion (OTEC) plant attempted off-Tuticorin in 1000 m water depths and the barge-mounted desalination plant demonstrated off-Chennai, NIOT has established 100 m3/day capacity low temperature thermal desalination (LTTD) plants in the Kavaratti, Minicoy and Agatti Islands (Figure 15) in the Union Territory of Lakshadweep, where cold water is drawn from 300 m water depths using a high-density polyethylene pipe. The LTTD based technology is feasible for islands as the depth for mooring the cold water is closer to the shore compared to main land. As these desalination plants have improved the health of the islanders, installing LTTD-based desalination plants in six more islands of India has been undertaken (Purnima et al. 2012; Energy & Fresh Water, 2018). Design of an open-cycle OTEC-powered LTTD-based desalination plant capable of producing fresh water of 100 m3/day and an electricity co-generating capacity of 100 kW is undertaken in the Kavaratti islands. The system shall involve a low differential pressure steam turbine and a cold sea water input at 8.5 °C. For aiding the plant design, a laboratory capable of simulating the OTEC-desalination cycle is established at NIOT. The LTTD-based technology for utilization of the condenser reject heat from thermal power plants is demonstrated in the coastal North Chennai thermal power station and is being extended to similar plants.