A brine evaporative cooler/concentrator for autonomous thermal desalination units

Abstract

In recent years growing attention has been paid to the problem of brine disposal due to the raising awareness of significant environmental issues related to the use of desalination processes for fresh water production. This is particularly relevant when desalination units are located in remote sites, characterised by major complexity in the construction and management of intake and outfall structures. In the present work a novel device, named Brine Evaporative Cooler/Concentrator (BECC, patent pending), has been developed for coupling with small-scale thermal desalination plants in order to reduce the problem of brine disposal. Such device fulfils two different functions: i) cooling of the recirculating brine (which is often mixed with cold seawater to feed the unit, acting first as a cooling medium for the condensation of the vapour) and ii) concentration of the brine to de disposed. The BECC device is based on the principle of evaporative cooling, i.e. a primary liquid stream is cooled by means of a secondary liquid stream (by-pass stream), which in turn evaporates in contact with atmospheric air, thus being cooled naturally. The two streams are separated by a heat-conductive surface, through which heat is transferred from the primary stream to the cooling-evaporating by-pass stream. A lab scale BECC pilot unit has been designed, constructed and tested. Geometrical and operating features have been studied in order to allow the operation with concentrated brines, to minimise problems of corrosion, scaling and fouling. The first results have demonstrated the feasibility of the technology and a larger scale prototype unit has been designed for the installation within a 5 m 3 /d Solar Membrane Distillation unit to be constructed in Pantelleria island (Italy).

Hybrid desalination processes for beneficial use of reverse osmosis brine: Current status and future prospects

“…Nevertheless, MVC is preferentially considered for ZLD in industrial wastewater treatment. In addition to MED and MVC, thermal brine concentrator is another technique for SWRO brine treatment [32].…”

Reactive crystallisation process for magnesium recovery from concentrated brines

“…In fact, while in the past, brines were treated as a simple waste to be just disposed back into a receiving water body or to be treated before disposal; nowadays, a major concern has been raised both in terms of environmental safety and process sustainability [1][2][3]. This is, in fact, related to a bigger attention to environmental problems generated *Corresponding author.…”

Downstream processing of reverse osmosis brine: Characterisation of potential scaling compounds

“…One option for sustainable management of RO brine is concentration and recovery of salts, which results in the production of more desalinated water and near zero wasteliquid discharge (ZWLD) (Bond and Veerapaneni, 2007). Salt recovery from brine can be achieved using evaporative separation technology, although such technologies are highly susceptible to the formation of scale (Cipollina et al, 2011;Mericq et al, 2010). Mineral precipitation and scaling occur when the concentrations of scale precursor ions (Ca 2þ , Mg 2þ , Sr 2þ , Ba 2þ , OH À , SO 4 2À , CO 3 2À , H 3 SiO 4 À , etc.)…”