Seawater-Powered Hydrogen Reactor can Fuel a Submarine for 30 Days
Tony Pulsone
MIT scientists have found an intriguing new method to produce hydrogen fuel using soda cans, seawater, and coffee grounds. They believe this chemical reaction could power engines or fuel cells in marine vehicles that use seawater.
Hydrogen plays a crucial role in decarbonizing energy production due to its clean-burning nature, high energy density, and the fact that its only by-product in fuel cells is water. However, a significant challenge is its storage and transportation. The small hydrogen molecules often leak through containers and pipes, leading to losses and potentially causing environmental issues.
On-Demand Hydrogen Production Using Aluminum Pellets for Marine Vehicles
MIT’s new method offers a way to produce hydrogen on demand directly in a vehicle. Instead of storing and transporting hydrogen, you would only need to carry aluminum pellets, which are more stable and manageable.
In tests, a single 0.3 g (0.01 oz) aluminum pellet in fresh, de-ionized water generated 400 ml of hydrogen in five minutes. Scaled up, one gram of pellets could produce about 1.3 L (0.3 gal) of hydrogen in the same timeframe.
Overcoming Reaction Limitations
The process relies on a straightforward chemical reaction: aluminum reacts strongly with oxygen, stripping the oxygen from water (H₂O) and releasing hydrogen. However, this reaction typically doesn’t last long because aluminum oxide forms a layer on the metal, preventing further interaction.
To address this, the team pretreated the aluminum pellets with a gallium-indium alloy, which helps maintain the reaction by breaking down the oxide layer as it forms.
Tony Pulsone
One drawback is the rarity and cost of gallium and indium. However, the researchers discovered that performing the reaction in an ionic solution caused the alloy to clump together, allowing for easy retrieval and reuse. Seawater, being an ionic solution, proved ideal for this purpose.
Initially, the reaction slowed significantly in seawater, taking about two hours to produce the hydrogen that fresh water produced in five minutes. The breakthrough came when adding old coffee grounds sped up the reaction back to five minutes. The key was imidazole, a compound found in caffeine.
Developing Hydrogen Reactors for Marine Vehicles Using Aluminum and Seawater
The researchers suggest using their method to develop practical hydrogen reactors for marine vehicles, which would eliminate the need to transport hydrogen. Instead, only aluminum and seawater would be required to generate hydrogen.
Lead author Aly Kombargi highlighted that this method could simplify maritime applications by removing the need for seawater or hydrogen tanks. The team will test it with an underwater glider that could run for up to 30 days using seawater and aluminum pellets.
To conclude, future applications might extend to trucks, trains, and airplanes, with possibilities including extracting water from ambient humidity to produce hydrogen. The study is published in Cell Reports Physical Science.
Read the original article on: New Atlas
