Thermo-economic analysis of chlor-alkali electrolysis for hydrogen production in the electrochlorination plant: Real case

This study deals with the implementations of electrochemical technology for the on-site production of sodium hypochlorite (NaOCl) and hydrogen from seawater for utilization in the steam power plant. The effects of electrical current and seawater temperature on the performance of electrochlorination system are investigated. The obtained results show that current efficiency increases with increasing electrical current. The current efficiency of the system is calculated as 94% at a maximum electric current with a value of 4000 A and maximum temperature with a value of 30 degrees C. Electricity consumption increases for the unit generation of available chlorine in the case of both enhancements of electrical current and seawater. Hydrogen generation is directly proportional to the variation of the electrical current. Also, improvement in seawater temperature provides more efficient hydrogen generation. Moreover, energy and exergy efficiencies of the whole system are positively affected by an increase of current. However, energy and exergy efficiencies are determined to be 50.4% and 3.04%, respectively, under the best operational conditions. Besides, the cheapest product cost of the hydrogen gas is calculated as $4.04/kg under the greatest electrical current and seawater temperatures. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

This study examines the implementation of electrochemical technology for producing sodium hypochlorite and hydrogen from seawater on-site for a steam power plant. The effects of electrical current and seawater temperature on the electrochlorination system are investigated. Results show that current efficiency increases with higher electrical current, with electricity consumption also increasing with enhancements in both current and seawater temperature.