Hydrogen for Maritime Application—Quality of Hydrogen Generated Onboard Ship by Electrolysis of Purified Seawater

Abstract

Maritime transport is investigating several options to reduce its greenhouse gases and air pollutant emissions. An experimental ship, Energy Observer, is using excess renewable energy to generate onboard hydrogen by electrolysis of purified seawater. As a promising option for storing energy, it can provide on-demand energy to the ship through a hydrogen fuel cell (FC). As hydrogen FCs lifetime and performance are correlated to hydrogen quality, the hydrogen produced onboard needs to be monitored. This study assesses the probability of contaminants presence for this electrolyser, using purified seawater and supports the results with a hydrogen fuel quality analysis from the Energy Observer ship. It demonstrates that an electrolyser using onboard purified seawater can generate hydrogen of a quality compliant with ISO 14687:2019. Additional contaminants (i.e., ions, heavy metal) were also measured. The study highlights the potential contaminants to be monitored and future research on new contaminants from seawater to further develop hydrogen fuel for maritime applications.

Electrolysis of Tertiary Water Effluents─a Pathway to Green Hydrogen

“…13 RO membranes have been previously reported for treating seawater before a PEM electrolyzer. 31 In this case, the seawater was desalinated with two RO semipermeable membranes, rejecting 99.2−99.5% of the salt in the seawater, to reach a water conductivity of ∼3 μS/cm. The conductivity was then further reduced to 0.5 μS/cm by using a polyamide thin-film composite membrane and a mixed-bed resin filter.…”

“…The later, containing about 62 ppm of Na + , 51 ppm of Ca 2+ , 7 ppm Mg 2+ , and 79 ppm of Cl − , would need to be further purified before electrolysis 32 RO membranes can also act as a barrier to dissolved inorganic matter as well as organic molecules with a molecular mass greater than 100 Da. 31 In this work, a 0.001 μm RO membrane was used with the expectation to achieve a rejection rate >99% for the dissolved ions and the large organic molecules. 33 As shown in Table 1, the use of RO successfully removed most of the impurities, with the water conductivity decreasing from 900 to 13 μS/cm.…”

Fractional Order PID Design for a Proton Exchange Membrane Fuel Cell System Using an Extended Grey Wolf Optimizer

“…The activation losses occur due to the kinetics of the reactions taking place at the electrode. They can be calculated using Equation (10) [34].…”

“…Scientists have already developed different types of fuel cells, characterized by the nature of the gases and electrolytes used, thereby determining their operating characteristics. Of all the existing families of fuel cells, the proton exchange membrane fuel cell (PEMFC) achieved the most attention from the researchers, which is considered the best appropriate for the automotive sector [7] and numerous fields [8][9][10]. The strong points of this fuel cells type are the relatively fast dynamic compared to other power generators and low operating temperature, from 40 • C to 100 • C, which facilitates its integration in a vehicle without specific thermal insulation [11,12].…”

Investigation of the Impact of Chloride Contamination on Degradation in PEM Water Electrolyzer Cells

“…In offshore applications or fresh water scarce regions, salt water is used as source and thus, additional desalination processes need to be implemented. After the purification, desalinated seawater still contains low amounts of ionic contaminants 3 . Among the most detrimental impurities, chloride ions (Cl − ) can result in severe degradation of the main components of the membrane electrode assembly.…”