UTILIZATION OF DESALINATION WASTE BRINES AS IONIC FEEDSTOCK FOR CARBON SEQUESTRATION THROUGH CARBONATE MINERALIZATION PROCESS

Rising numbers of desalination plants worldwide will probably generate environmental challenges in waste brine disposal. This study tests whether desalination waste brines (DWB) can be used as a feedstock for ions necessary in carbon sequestration method that results in the production of carbonate minerals. Mass balance calculations were used to determine total mineral output for the formation of minerals such as Na₂CO₃, CaCO₃, MgCO₃, and KCl.

Two sizes of desalination plants were evaluated for potential mineral yield from their waste brines. Carbon emissions from power plants local to the desalination plants of choice were utilized in conducting the equations. The Al Jubail II Dual Purpose Desalination and Power Plant (Saudi Arabia) serves as an upper limit example for this process, while the Telde Desalination Plant represents an “average” sized desalination plant. The nearby Barranco De Tirajana Power Plant (Telde, Canary Islands) is a potential source of carbon dioxide for mineral production from the Telde desalination waste brines.

Results from mass balance calculations and literature review are integrated to assess potential mineral output and industrial utilization. The feasibility of this process is assessed through primitive energy requirement calculations, potential economic value of additional minerals present in DWB, and storage situation assessment.

Estimated mineral commodity production values at the two localities range widely in magnitude. Production potential in the Al Jubail Dual Purpose Desalination and Power Plant may rival world production (10⁵ -10⁷ tonnes/year) for some industrial minerals. Mineral production in the Telde area is limited by DWB output and ranges on the orders of 10⁴ -10⁵ tonnes/year.

The Telde area appears unsuitable for surficial storage due to the small landmass of the Canary Islands and high density of residential and commercial buildings on the Gran Canaria Island. The Al Jubail II Plant appears promising with regards to surficial storage due to the large, arid landmass of the Saudi Arabian peninsula.

This process is hindered by the relatively high cost of CO₂ sequestration compared to other methods. Drawbacks include high start-up costs, infrastructure development, and logistics of mineral separation necessary to obtain distinct mineral commodities.