CuO/water and Al2O3/water nanofluids as working fluid in an abandoned oil well to improve thermal performance in the seawater desalination process

Abstract

BackgroundAbandoned Oil/gas wells could be employed as heat sources for various technical processes such as seawater desalination. MethodsIn this study, the thermal performance of an abandoned oil well is enhanced by the addition of nano Cu and Al2O3 particles into the working fluid (water) and by using two distinct thermal insulations in the coaxial double-pipe borehole heat exchanger to decrease heat losses of the heated working fluid. Diligent simulation of the process was carried out using the k-ω SST turbulence model and sweep meshing method. The effect of Cu/water and Al2O3/water nanofluid concentrations on extracted fluid temperature was investigated. Significant FindingThe results revealed that 0.5 wt.% of Cu/water and Al2O3/water as working fluid at a flow rate of 2 kg/s raised the extracted fluid temperature by 14% and 12.9% compared to pure water, respectively. Also, SiO2/GO composite thermal nano-insulation could improve heat loss by 7.4% compared to polystyrene thermal insulation. Furthermore, 806 m3/day of potable water was produced by a multi-effect distillation modified with flash-boxes desalination, where brines were reused as a secondary feed for potable water production. Noticeable increase achieved compared to conventional multi-effect distillation systems.