Produced Water Based Green Hydrogen Production Using an Anion Exchange Membrane Water Electrolyzer (AEMWE) System

Abstract Considerable volumes of produced water are generated along with hydrocarbons in oil & gas fields worldwide. Such vast quantities of produced water can be transformed from a waste stream that requires handling and disposal to a valuable resource that generates significant economic and environmental benefits. If this produced water can be recycled and utilized for low-carbon energy applications, it becomes a game changer to promote circular water economy, sustainability, and support the energy transition. Green hydrogen, the optimal energy carrier, plays a crucial role in connecting smart grids and scaling up low-carbon energy generation. This study experimentally investigates the feasibility of using treated produced water obtained from zero liquid discharge (ZLD) desalination technology for H2 generation using proton exchange membrane water electrolyzer (PEMWE) and anion exchange membrane water electrolyzer (AEMWE) systems. For evaluating the quality of treated produced water, the current density was measured by I-V measurement at controlled temperature (60°C). Also, it was measured with and without additional purification process to evaluate the suitability of treated produced water as direct resource for H2 production. The results from PEMWE showed different measured voltages with (1.8 V at 1.5 A/cm2) and without (2.5 V at 1.5 A/cm2) additional purification process. This finding indicates that impurities in treated produced water will have a negative effect on the performance of the PEMWE to lower the energy efficiency. On the other hand, the measured voltage from AEMWE showed consistent performance with (2.3 V at 1.5 A/cm2) and without additional purification process. Such result confirms the robustness of AEMWE to generate H2 with almost similar energy efficiency using treated produced water with and without further purification, when compared to PEMWE. This means the treated produced water of ZLD technology can be directly used with AEMWE without any additional purification process to sustain the operation costs and H2 production efficiency. The results obtained from durability test and optimized electrode materials were also presented to demonstrate the long-term reliability of AEMWE for enhancing H2 production efficiency with treated produced water. This first-ever laboratory study demonstrates the successful and direct utilization of treated produced water using the AEMWE for green H2 production. The upscaling of AEMWE technology has huge potential to recycle produced water and it can also become a win-win technological solution to promote circular water/carbon economies and support the ongoing energy transition initiatives in the industry.