Time to look from Hydrogen from another viewpoint
I was reading through the RISO report on hydrogen economy, and this report (more than 1 year old) examined different ways of storing hydrogen.
In the chapter : Hydrogen system energy technologies in global, European and Danish perspective :
$this->bbcode_second_pass_quote('', 'I')nstead of molecular hydrogen (H2), substances known
as hydrogen carriers might be more effective as energy
vectors. Potential carriers are hydrocarbons, ammonia
(NH3) and methanol (CH3OH). All these substances are
already produced and handled in large quantities, so
they have the considerable advantage that a suitable
infrastructure is already in place. Hydrocarbons are the
most effective hydrogen carriers known, and they can be
produced in a CO2-neutral manner using water, CO2 and
energy as the raw materials
PeakOil is You
THE Ammonia Fuel/Energy Storage Thread
THE Ammonia Fuel/Energy Storage Thread
by EnergySpin » Fri 05 Aug 2005, 02:08:33
Hm chemical storage vehicles of hydrogen? How dow the compare to other fuels? Lets consider the following heat capacity data of various fuels:
Hydrogen (pure) 61000 btu/lb
gasoline (cars) 20400 btu/lb
gasoline (aviat) 18110 btu/lb
methanol 10258 btu/lb
ammonia 9667 btu/lb
wood 6500 btu/lb
hydrazine (space shuttle fuel) 8345 btu/lb
Historical sidenote: industrial methanol and ammonia synthesis did not rely on natural gas feedstocks but by electrolyzing water and combining it with atmospheric CO2 or Nitrogen
The funny thing is that a significant infrastructure exists for ammonia and methanol distribution and that both these fuels can be used in ICEs (as well as fuel cells). Even though their specific combustion heat is approximately half the one specific heat of gasoline, they do not require the expensive storage that hydrogen requires (in fact they are stable under storage for months).
The advantages (especially of NH3) were detailed on 2 journals. First one was in Mechanical Engineering 2 years ago (click me) and the second one was a letter send to Physics Today last month by Peter J. Feibelman (can be read here)
Even though there are some toxicities associated with ammonia
1) it is not flammable as hydrogen is, and can be stored in liquid form at 8 bar (contrast that with the 250 bar of presurized hydrogen storage)
2) It is not a greenhouse gas
3) it burns cleanly to nitrogen and water
4) leaks can be detected by our noses at 1/5000 the toxic level (any of you who has worked with ammonia in a lab can testify to that)
5) An ICE design (actually similar to the one used in cars today) has been designed by Sandia National Laboratories (read here)
why aren't people discussing this low technology solution to a liquid fuel problem? Granted electricity generation capacity will be needed ... but the electricity generation capacity IS NOT our problem ... nukes (even though people dislike them,) big and small hydro and wind can more than double electricity generation capacity.
Since people might have discussed this H2 storage before, I hope you could shed a light why this route is not pursued. For example the original Physics Today Letter on the hydrogen economy (read here) never mentioned ammonia and methanol as storage mediums for a "hydrogen economy" (but to be fair ammonia appears in Figure 4 where different high tech hydrogen storage media were considered). What is also interesting is the answer that Crabtree, Dresselhaus and Buchanan gave Feibelman about ammonia:
$this->bbcode_second_pass_quote('', 'P')eter Feibelman raises a good point in advocating NH3 as a hydrogen storage medium. He points out many advantages, including its high storage capacity, the significant ammonia infrastructure already in place, and our extensive chemical knowledge and industrial experience with ammonia.
The problem of effective hydrogen storage is one of the most challenging in the hydrogen economy, and we should pursue all promising options. The use of ammonia in a hydrogen economy has been discussed since at least the 1970s; Ali T-Raissi summarizes its history and its possibilities.1 The subject remains vibrant today; new mechanisms for the release of hydrogen from ammonia over catalysts at acceptable temperatures are continuing topics of research.2 A major challenge is toxicity, as Feibelman points out, but all hydrogen storage proposals come with safety issues.
Ammonia can be used effectively in other hydrogen storage media as well,1,3 notably in combination with its borane analog, BH3. NH3BH3 releases more than 12% of its mass as H2 in decomposing to NHBH at low temperature and ambient pressure. Its release rate and decomposition chemistry can be significantly improved by nanoscale structuring in porous hosts.3 This example shows how the richness of hydrogen chemistry and the influence of nano-patterning lead to new horizons in hydrogen storage.
They totally evaded the question, even though in their original article about the hydrogen economy they identified the following targets for a hydrogen economy:
$this->bbcode_second_pass_quote('', '[')b]The two challenges for on−vehicle hydrogen storage and use are capacity and cycling performance under the accessible on−board conditions of 0−100°C and 1−10 bars.
BTW these conditions are achievable today with methanol and ammonia without an Apollo type of project.
Ali T-Raissi wrote about the ammonia prospect in the Proceedings of the 2002 U.S. DOE Hydrogen Program Review. Reading that report was hilarious ... work on the subject was done 35 years ago:
$this->bbcode_second_pass_quote('', 'T')he use of ammonia as chemical hydrogen storage compound that can be easily dissociated and used in the fuel cells and power plants is not new and has been ongoing for more than 40 years [1-58]. In the early 1970s when the concept of "Hydrogen Energy Economy" was widely debated, it was envisioned that ammonia (NH3) would provide a perfect storage medium for hydrogen produced by the ocean thermal energy conversion (OTEC) plantships [16,32]. In the early 1980s, Strickland at the Brookhaven National Laboratory (BNL) conducted a systems study to determine the economic prospects of using anhydrous liquid ammonia, produced by OTEC, as a hydrogen carrier for annual H2 demand of 10-100 million standard cubic feet [28,31]. BNL study showed that OTEC NH3 was competitive with H2 made at the point of use via water electrolysis, steam reforming of natural gas, or OTEC liquid hydrogen (LH2), in the upper fifth of the use range. In another BNL study, three alternative transportation fuels (ATFs) were compared with respect to the input energy required for their production from NG, their H2 storage capacity and cost per unit of energy contained ($/million BTU)[26]. The ATFs chosen were LH2, hydrogen produced by steam reformation of methanol (MeOH), and H2 generated via thermocatalytic dissociation of anhydrous liquid ammonia. The BNL results showed that anhydrous liquid ammonia had considerable advantage over MeOH and LH2, coming very close to matching gasoline performance as a motor fuel.
It gets even better in the next paragraph .....
$this->bbcode_second_pass_quote('', '[')b]As the 1980s drew to close and with the demise of non-fossil hydrogen production technologies as a near-term reality, ammonia disappeared as a viable hydrogen storage medium from the U.S. DOE programs [57]. The commonly held view was that OTEC would be roughly twice as expensive as the conventional energy forms due to the high capital cost of OTEC plants made under existing designs at that time. It is often stated that a $40/barrel oil cost would be necessary to spur investors into seriously considering OTEC technology [58]. The total energy efficiency is lower with ammonia as the H2 carrier compared to methanol. Therefore, if methane is used as the primary fuel, then methanol will likely be the liquid fuel of choice for fuel cells, especially PEMFCs. Presently, the DOE fuel cell for transportation program appears to be focused on the use of fossil fuels and for that reason ammonia is not generally considered as a viable H2 carrier.
![[smilie=eusa_wall.gif]](https://udev.peakoil.com/forums/images/smilies/eusa_wall.gif "eusa_wall")
The ammonia scenario was unique to the OTEC project, where the electrical energy would be generated at a remote location and it was not feasible to install either power lines or a hydrogen pipeline to the shore. Hydrogen production and subsequent conversion to NH3 for shipment to the shore seemed to be the most attractive way to store and transport OTEC hydrogen. Using ammonia directly in the fuel cells then appeared to be the most plausible approach. In other words, in the case of solar/renewable hydrogen production, ammonia can still be viewed as a viable chemical storage medium for supplying hydrogen to fuel cells, especially AFCs.Another beauty from the same report:
$this->bbcode_second_pass_quote('', '.')...Much effort has been expended to develop steam reformation of methanol as a process for generating hydrogen for use in fuel cells. Nonetheless, a comparison of the economics of H2 production via ammonia decomposition for alkaline fuel cells versus methanol reformation for acid fuel cells has shown that ammonia decomposition is economically more favorable [40,41,55]....
Regarding the health effects of the ammonia it is true that it is a toxic compound as well as any of the other fuels (i.e. methanol) and even gasoline fume but maybe there is another reason why ammonia (besides the obvious (in bold in a previous section).
$this->bbcode_second_pass_quote('', '[')b] For example, anhydrous ammonia is used, extensively, in the manufacture of illicit drug methamphetamine. Anhydrous NH3 is used in the so-called "Nazi method" to spur methamphetamine production [83]. This method does not require extensive knowledge of chemistry, uses no heat, and is much simpler technique than the ephedrine-pseudoephedrine reduction or "Red P" method that is also used for producing methamphetamine. Due to these and other considerations, it appears unlikely that NH3 will find widespread use as a high-density chemical carrier for H2 in the future transportation applications. This is despite the fact that ammonia is a superb fuel for power plants, in general, and fuel cells, in particular. Furthermore, due to economic and energy efficiency considerations, it will be advantageous if a method could be found that completely eliminated the need for or greatly simplified the function of the on-board NH3 reformer. One approach to mitigate ammonia's shortcomings is to complex NH3 with other hydrides so that the resulting compound is stable but not toxic or cryogenic. The prospective process must produce a compound that contains H2 at gravimetric and volumetric densities comparable to that of anhydrous ammonia. A class of compounds (with generalized formula BxNxHy) known as amine-boranes and some of their derivatives satisfy this requirement.
Any thoughts? Simple chemicals which do not rely on massive infrastructure and can burn in regular ICEs have been available since the 70s (If I'm not mistaken, there was an ammonia steam engine running in 19th century France). Storage becomes much less of an issue with these fuels, which are stable over months. Energy content is half of gasoline but they can be transported cheaply without the hurdles of liquid H2.
Collin Campbell himself mentions the generation of NH3 as a hydrogen carrier in an interview he gave 3 years ago in a FEASTA conference in Ireland (even though he never mentioned the fact that the bona fide Haber process i.e. the catalytic reaction of N2 and H2 IS NOT DEPENDENT ON FOSSIL FUELS)
$this->bbcode_second_pass_quote('', 'I') know of one project of trying to glass over the stony desert of Australia which has very high solar radiation, use this solar electricity to electrolyse water, with which to make hydrogen, and then from the hydrogen use coal there to transform this into ammonia and methanol which are easier to transport than hydrogen itself. So you ship this ammonia and nitrogen to Europe and then re-form it back into hydrogen. But this whole interest in hydrogen is primarily from a climatic standpoint, and I don't think it has particular meaning in relation to energy supply itself. Certainly hydrogen a desirable thing from a climatic standpoint, an emissions standpoint, but you've got to make the stuff in the first place. And a supply of ordinary natural gas will run a fuel cell perfectly well. There is this idea of a fuel cell under the stairs in everybody's house, you know, that would give heat and electricity and so on. So there are solutions in that direction too.
