Earlier this week, one of the readers of this blog, Nute, had made a comment on another section of this blog in November about the possible use of hydrogen slurries to aid in the development of the fledgling H2 infrastructure. I would like to follow up on this today.
A hydrogen slurry is a liquid chemical compound that is relatively safe, can be stored at room temperature and can be pumped, poured and transported like any other liquid. Liquid hydrogen slurry such as magnesium hydride (MgH2) or lithium hydride (LiH) could be used in either a centralized or decentralized fueling infrastructure.
Since MgH2 is cheaper, a company like Safe Hydrogen has been testing this hydrogen slurry with the help of the U. S. Department of Energy (DOE). The MgH2 slurry is combined with water to create hydrogen gas and the byproduct is Mg(OH)2, also known as Milk of Magnesia.
This Milk of Magnesia is an inert compound the can be easily recycled back into magnesium hydride. One of the advantages that hydrogen slurry has over super-cooled liquid hydrogen is that it has almost double the energy density. Another advantage is that hydrogen slurry is much cheaper to produce and requires much less energy than super-cooling liquid hydrogen.
Hydrogen slurry can be pumped into a hydrogen ICE or fuel cell car with onboard reformation into pure hydrogen and the byproduct pumped out later for recycling. Or, a more consumer-friendly method would be that the hydrogen slurry could be reformed at the fueling station into pure hydrogen, pumped into the car and the fuel station could recycle the hydrogen slurry byproduct.
With the state that the economy is in today, we are going to need more Milk of Magnesia to get us through. Why not create hydrogen along the way as a means to cleaner skies, more oil independence and increased jobs in this emerging marketplace? This idea won’t be that hard to digest.
Here is an email I received after posting this article from Safe Hydrogen CEO, Ken Brown:
Kevin,
Thank you for your inquiry.
In 2008 we completed our project with the DOE investigating the reaction of the slurry with water. The main conclusions:
1. We can mix the slurry with water and release hydrogen in a controlled rate.
2. Enough slurry and water can be stored on board an automobile for 300+ miles of range.
3. The slurry system can meet the DOE goals for 2010 storage volume and energy density.
4. To be economical, slurry must be used on a large scale(about 25% of US auto market)
5. Large scale cost of the slurry system is about $4.50 per gasoline gallon equivalent.
Although there are obvious advantages to the slurry over high pressure hydrogen tanks for on-board storage, it is our opinion that the auto companies will stick with high pressure hydrogen storage because of its simplicity. It is also our opinion that there are still two major hurdles that have to be overcome before we will see wide adoption of fuel cell powered vehicles. The first is the delivery of competitively priced hydrogen and the second is competitively priced fuel cells.
Since early in 2008, we have concentrated on the release of hydrogen from the slurry with heat. Although the energy density is less, this use of the slurry has a major advantage–low price. We believe and can show with detailed calculations that we can deliver a kg of hydrogen (equivalent in energy to a gallon of gasoline) for under $3 cost. The key to reaching this cost is being able to load and discharge hydrogen from the slurry many times. We have cycled the slurry so far for 50 times which is the minimum number needed to meet the $3 cost.
Since autos with internal combustion engines can run on hydrogen and since we believe that our technology can enable the delivery of competitively priced hydrogen to fueling stations, hydrogen use in transportation can become a reality in the near future.
We are currently working on designs needed for scaling up our technology.
Ken Brown
http://www.hydrogendiscoveries.com/index.html
Is an interesting site to look into as far as the infrastructure issue is concerned.
Apparently, there is work being done to create hydrogen pipelines that can handle gaseous hydrogen. I don’t know if the above site should be believed, but I imagine that some fact checking is possible.
Maybe people working on hydrogen pipelines that can handle gaseous hydrogen should seriously consider the work of safe hydrogen LLC. Why go with an expensive pipeline if you don’t have to? I think the hydrogen economy will materialize sooner if chemical hydride slurry technology is leveraged.
Is it true that the Toyota FCHV SUV can go 400+ miles on 6 kg of 10k PSI hydrogen?
In addition to the polymer/aluminum pipeline technology mentioned above, Hydrogen Discoveries also developed a magnesium hydride fueling system.
Although the Hydrogen Discoveries fueling system was different, the scientists at Hydrogen Discoveries agree with Safe Hydrogen that magnesium hydride is the best solid hydrogen fuel.
However, once Toyota announced in the fall of 2007 that the FCHV mid-size SUV would get 480 miles of range (Toyota announced last June that the FCHV-adv gets 516 miles of range), it started to become very clear that the auto companies were going to go with high-pressure hydrogen tanks.
As Ken mentioned, they are quite simple. And the 300-mile driving range and safety issues are no longer a concern.
Once it was clear the hydrogen storage problem had been solved, Hydrogen Discoveries focused on developing the polymer/aluminum pipeline technology.
Toyota announced earlier this week that they would begin commercializing hydrogen fuel cell vehicles in 2015. This seems to be the approximate date that many companies have in mind for the beginning of mass production of hydrogen fuel cell cars.
It will obviously take some time to get the fueling infrastructure built. Frankly, six years isn’t very much time.
Here is a link with my thoughts on hydrogen internal combustion engine vehicles:
And here is a wind-to-hydrogen cost analysis that I did:
Although I have a lot of respect for them, my hydrogen cost figures (mainly the cents per kilowatt hour cost of electricity) are much more conservative than Safe Hydrogen. And it takes significantly less electricity to produce a kilogram of hydrogen via electrlolysis than to recycle the spent fuel back into magnesium hydride (50 versus, if I remember correctly, 85).
My analysis also includes doubling the taxes which adds about a dollar per kilogram. But I think this needs to be done, because people think in terms of the cost per gallon of gasoline at the pump which includes taxes.
It should be noted with solid hydrogen that the spent fuel would have to be transported via rail to where the electricity is generated.
If this were done on a very large scale, my guess is that a significant rail infrastructure investment might need to be made. From what I understand after reading a book on the coal industry a few years ago, railways are quite congested right now.
My view is that hydrogen fuel cell vehicles are so close that hydrogen internal combustion engine vehicles will not be produced. They are getting so close to being ready that it would almost be impossible to build the hydrogen fueling infrastructure before they are commercialized.
And hydrogen fuel cell vehicles offer much lower fuel costs and much greater driving ranges than hydrogen internal combustion engine vehicles due to their higher efficiency.
The Hydrogen Discoveries polymer/aluminum pipeline technology solves the cost and performance issues with carbon steel pipelines. Hydrogen pipelines are needed to bring hydrogen produced from stranded renewable sources of energy such as wind and solar power to consumers across the country.
Home hydrogen production is very expensive due to the cost of the electrolyzers and compressors. It would be much more economical for consumers to form local hydrogen fueling station cooperatives to take advantage of economies of scale.
In considering the home hydrogen fueling model versus the hydrogen fueling station model, the analogy that comes to mind is getting a gym membership.
Could you go out and spend up to tens of thousands of dollars to have your own fully-equipped gym at home? Of course.
But how many people do this? And how many people are a member of a local gym along with hundreds of other people?
Furthermore, hydrogen fueling stations with on-site production from solar power are not viable. The SMUD hydrogen fueling station in Sacramento has on-site hydrogen production from large solar panels, but only 12 kilograms of hydrogen are produced every day. The solar panels needed to supply a hydrogen fueling station with 1000-1500 kilograms of hydrogen per day take up way too much space to be located on-site.
From the point of view of Hydrogen Discoveries, the polymer/aluminum hydrogen pipeline technology is the critical link for the dream of a “green” hydrogen economy to become a reality.
Greg Blencoe
Chief Executive Officer
Hydrogen Discoveries, Inc.
Okay, so 85 kw is a lot more than 50 kw. Here’s the thing, how much hydrogen
will be lost if it is kept in gaseous form and sent through both pipelines and trucks to fueling stations? I realize now that Magnesium Hydride Slurry costs almost the same as electrolysis in electricity, but what if hydrogen is produced using say bacteria to crack water?
The problem I have with what I’ve seen of hydrogen discoveries plans is that
they are still talking about shipping hydrogen on trucks without converting it
from gaseous form to something else. Even a solid metal hydride if you are
trucking hydrogen probably makes sense. The problem with gaseous hydrogen
is that you can’t compress it enough to get enough hydrogen on the truck to
be worthwhile. If you have to make more trips to deliver hydrogen than you
do to deliver gasoline, there’s a problem. Can hydrogen be compressed
beyond 10k PSI both safely and cost effectively?
The beauty of Magnesium Hydride Slurry is that you don’t have to modify existing fuel trucks much to carry it. I guess the downside is that you have
to come up with almost the amount of energy it will take to get hydrogen via
electrolysis to make the slurry in the first place.
Maybe it’s time to talk about nuclear plants and solar collectors on the moon
with a microwave transmitter to send power back to earth. Whoever can figure
out how to buiild a significant number of solar collectors in space will be able
to tap into zetawatts worth of power.
I’m interested in how viable bacterial approaches to getting hydrogen are. If
hydrogen can be collected without using expensive metals and electricity in
sufficient bulk, spending 35 kw of electricity to create a slurry doesn’t seem
so bad.
All indications are that the car companies are moving forward with 5000 and 10,000 psi high-pressure hydrogen tanks. And the BMW hydrogen car has a liquid hydrogen tank. They are very simple and have been proven to work in hydrogen vehicles that are on the road today.
One option is to transport liquid hydrogen instead of high-pressure hydrogen in trucks. Trucks that deliver liquid hydrogen can hold about 4000 kilograms of hydrogen. The typical gasoline tanker trucks holds about 8000 to 10,000 gallons of gasoline. The hydrogen would then be compressed at the fueling station.
It would likely cost around $0.75 to $1 more per kilogram of hydrogen to do this, because of the energy necessary to liquefy hydrogen.
But it would still be less than $8 per kilogram in the following analysis (which includes information on compressing hydrogen) in the link below.
Since the Toyota FCHV hydrogen fuel cell vehicle (mid-size SUV) gets about 80 miles per kilogram, this would be about the same as paying $2 per gallon of gasoline in a car that gets 20 miles per gallon.
Greg Blencoe
Chief Executive Officer
Hydrogen Discoveries, Inc.
I amazed with the analysis you made on hydrogen slurry. i think this is the most unique process for cars that i’ve see come along. filler uip with slurry. i can’t wait to get my first hydro car fueled by this.