Power Production from Produced Waters via Reverse Electrodialysis: A Preliminary Assessment

Abstract

Wastewaters generated by crude oil extraction processes, called “produced waters” (PWs), are complex solutions that contain organic compounds, mainly hydrocarbons, and often exhibit high salinity. The large amounts of PWs represent a global issue because of their environmental impact. An approach widely used in the oil industry is the reinjection of this wastewater into the extraction wells after a suitable treatment. The high salt concentration of such solutions may be used in salinity gradient technologies to produce green electricity. Among these technologies, reverse electrodialysis (RED) is one of the most promising. In this work, the application of RED for energy generation from two different real oil industry brines was investigated. An experimental campaign was performed by testing 10 × 10 cm2 units in long-run continuous operations, monitoring the performance for more than 25 days. Fouling phenomena, occurring during the continuous operation, decrease the unit performance and several anti-fouling strategies were adopted to tackle this issue. As a result, a positive net power density for up to 18 days of continuous operation was obtained. A maximum power density of about 2.5 W/m2 was observed, demonstrating how the RED technology could be an important strategy to harvest energy from an industrial waste.

Fluidics for energy harvesting: from nano to milli scales

“…In contract of the CEM, where the main problem is scaling and the solid particles. In the other hand, the fouling in the spacer can directly detect by a drop pressure jump inside the cell 204 and channel clogging, shown by Cosenza et al , 203 due to bacteria growing in the channels of the RED unit and in the dilute solution circuit, hence, The fouling is most probably in river water.…”

“…With these strategies, they were able to ensure a positive net power density value for more than 18 days using feed from oil well industry. 203…”

“…They reported that natural organic matters reduced power densities by up to 43%. Cosenza et al 203 tested different solutions from oil industrial wells, where the high concentrated solution contains an important amount of organic and dissolved solids, and the diluted solution was prepared with 0.7 g L −1 NaCl solution. They measured a greater resistance (around 40% at less concentrated solution) for the natural one compared to a NaCl-artificial salt water causing a 17% power loss.…”

“…With these strategies, they were able to ensure a positive net power density value for more than 18 days using feed from oil well industry. 203 3.2.7 Scale up. After the lab test, researchers tried to exploit the RED technology at an industrial scale (Table 7).…”

Desalination of oilfield produced waters via reverse electrodialysis: A techno-economical assessment

“…Among emerging technologies, Reverse ElectroDialysis (RED) can take advantage of this high salinity in order to valorise PWs by producing electric energy as already demonstrated by Cosenza et al [30]. Interestingly, while RED is producing energy, it intrinsically performs a controlled dilution of the PWs and could be adopted as a pre-treatment for downstream treatment steps based on bioremediation.…”