Colorado School of Mines team develops catalytic membrane reformer for efficient generation of H2/NH3 fuel mixtures
17 August 2022
A team at the Colorado School of Mines has developed a catalytic membrane reformer (CMR) for the efficient generation of hydrogen (H2) and ammonia (NH3) fuel mixtures. A fraction of the ammonia is decomposed, and the released hydrogen is extracted through a membrane, where it combines with the remaining ammonia, which is used as a sweep gas. A paper on yheir work is published in the ACS journal Energy & Fuels._
Ammonia is seen as an attractive carbon-free fuel, although it often requires the addition of a promoter such as hydrogen to ensure efficient and complete combustion.
Sitar et al.
The use of ammonia as a sweep stream in the study increased hydrogen recovery by as much as 60% and reduced the CMR operating temperature to as low as 350 °C.
Dynamic control of the H2/NH3 ratio is achieved by adjusting the sweep flowrate, and the rejection of N2 enhances fuel quality. The use of the sweep enables high H2 recovery under isobaric operation, producing high-pressure H2/NH3 fuel mixtures without the need for compression.
The excellent durability of the CMR was demonstrated through nominally unchanged performance over more than 1500 hours of operation.
This compact reformer provides on-demand generation of H2/NH3 fuel mixtures from a single fuel source that may serve as drop-in replacements for hydrocarbons to provide clean combustion with minimal equipment modification. Finally, the CMR concept may be applied for hydrogen enrichment of other fuels, and we successfully demonstrate the generation of H2/CH4 mixtures using methane as the sweep gas.—Sitar et al.
Rok Sitar, Javishk Shah, J. Douglas Way, and Colin A. Wolden (2022) “Efficient Generation of H2/NH3 Fuel Mixtures for Clean Combustion” Energy & Fuels doi: 10.1021/acs.energyfuels.2c01822
Reforming is an intense process using fossil feedstock and high levels of energy and some say it is more polluting than the oil refinery process . Oil companies are pushing hydrogen as the preferred fuel b/c the feedstock is fossil fuel; E.g., natural gas, crude oil, etc...and, they see the energy future as pretty much the same system that's in place now except instead of gasoline, we will receive hydrogen at the pumps; hydrogen produced by reforming not water hydrolysis.
It will be interesting to watch it all shake out.
Posted by: Lad | 17 August 2022 at 10:23 AM
Lad the assumption going forward is that the NH3 and H2 will be from renewable sources. For mass consumption it would be utterly pointless to do otherwise.
You're also far too rigid in what you're in favor of- you're against it unless it's perfect.
That's a vision that will result in crisis, economic doom, and miserable people. It can't and won't happen. The Europeans have just learned this lesson and they've stepped back from the brink just in time.
In your other comment today you suggested geothermal as an alternative along with wind and solar- this is unrealistic, as geothermal power generation barely exists at the moment, we can't just suddenly tap it. That's like saying 'we will get 31% of our electricity by ocean wave power by 2026' . We have no experience in harvesting useable amounts of energy by this method, it's like where we were with wind energy in 1965. Your vision is that of 'perfect power generation' , by the stroke of the pen and the laws passed, 'because we have to'. This is not reality. Reality is a slow and affordable migration away from high impact sources to low impact sources, with intermediate steps along the way, while not closing out entire industries, and while allowing people to make profits.
Posted by: The Lurking Jerk | 17 August 2022 at 01:17 PM
FWIW, TLJ, is that I'm not quite a ruthless perfectionist... but I refuse to endorse anything that is
I'm certain that we CAN get to negative. We have to do this via an intelligently and pragmatically designed scheme incorporating bio-derived fuels, mostly NON-bio energy, and integrated resource planning.
- worse than we can accomplish today, and
- does not place us on a path to zero or negative emissions. In other words, no "natural gas bridge to nowhere".
NONE of this will be simple or easy. We just have to do it.
Posted by: Engineer-Poet | 17 August 2022 at 08:37 PM
I would respectfully suggest that the differences in technology matter, and that lumping together all natural gas production is not legitimate.
So methane pyrolysis results in hydrogen and solid, not gaseous or liquid, carbon, which it is easy to sequester so that nothing leaks.
None of that indicates that this will become practical or economic, or shows anything either way about other technologies, but it is surely unwise to attempt a blanket dismissal of using natural gas if it does turn out to be capable of production with pretty much zero carbon release.
Posted by: Davemart | 18 August 2022 at 01:35 AM
We can get hydrogen in other ways. The world's production of the other product, carbon black, is only around 15 million tons; we can get that from biomass.
Posted by: Engineer-Poet | 18 August 2022 at 01:42 PM
' We can get hydrogen in other ways.'
We certainly can.
Here is the ramp up of electrolyser production by just one of the conglomerates involved, Siemens Energy/Air Liquid:
Ramping up to 3GW pa of electrolyser production by 2025 is a phenomenal growth rate, certainly comparable to any technical revolution which has taken place in the past.
TOTAL world installed capacity, not annual production, was a few hundred MW not so long ago!
We are going to have to agree to differ on hydrogen from NG though, which I support so long, critically, as it really is very low approaching zero GHG emission.
I advocate specifying and strictly enforcing ends, ie in this case very low GHG emissions, and leaving it to the 'mere technologists' to make it happen, anyway they fancy! ;-)
But importantly, those seeking to dismiss hydrogen, for often weird reasons, have lost, big time.
It is not going to be a battery only future, principally on the grounds that it is an impossibility.
None of that is to say that fuel cells are going to oust batteries in cars though, which appears perhaps to be the principle concern of battery only advocates, which led them into opposing all hydrogen initiatives, which is pretty difficult to implement as for a start it would mean doing without fertiliser!
Posted by: Davemart | 19 August 2022 at 01:25 AM