Posted by Michael Pardee on October 31, 2005, 12:53 am
As Graham points out, the initial production of the metallic boron has
byproducts (as does the production of the materials making up the rest of
the car) but the burning process does not release large amounts of boron or
boron oxide; they are recovered and separated into boron and oxygen again.
Obviously, *some* boron oxide will evaporate and that has to be dealt with
because of the scale of the operation. Another emissions problem is NOx;
since it burns at high temperatures (which is a requirement for efficiency
with any heat engine) it produces copious amounts of NOx. The big challenge
in NOx control for all air-oxidizer heat engines is to allow the gasses to
cool slowly enough to give the NOx time to dissociate.
Since it is solid fuel, fuel supply problems will not cause an immediate
loss of power as it does with fluid feed - it takes a while to consume the
local supply of fuel. Needless to say, boron won't work in an internal
combustion engine as the technology stands.
Personally, I don't see boron as a leading contender for vehicle power in
the near future, but I'm not ruling it out.
Posted by Earle Jones on October 31, 2005, 12:31 am
What is the chemistry of the reaction(s) that produce energy from
Boron? What type of engine is required?
Posted by Michael Pardee on October 31, 2005, 12:46 pm
It's an external combustion engine, like a stirling or rankine cycle engine.
That's one of the major sources of inefficiency in the concept. I tend to
think of boron as being a cleaner, rechargable version of coal... except, of
course, coal is an energy source while boron is only storage. The problems
with it are less than with hydrogen, but boron can't be used in fuel cells
without a breakthrough and that limits the potential efficiency.
Posted by gcowan on October 31, 2005, 3:10 pm
Michael Pardee wrote:
It is a Brayton-like cycle, semi-closed
to allow for injection of fuel and oxidizer,
internal combustion, and removal of B2O3.
"Michael Pardee" included
B2O3 has very low vapour pressure.
NOx is produced in quite small amounts,
small enough to scrub out with alkali,
although suspended particles of condensed B2O3
should be removed before the gas gets to this alkali.
It is burned in pure oxygen.
Seven times heavier, much more than seven times denser?
Bin packing densities for B2O3 are on the order of 1.2 kg/L.
How does he figure Li-ion batteries are over -- "much" over
-- 8.4 kg/L? They aren't. Two, maybe three kg/L, tops.
"Michael Pardee" included:
--- Graham Cowan, former hydrogen fan
boron as energy carrier: real-car range, nuclear cachet
Posted by Michael Pardee on October 31, 2005, 11:42 pm
Do you have a link for that? I haven't seen much on boron fuel and it looked
like they were talking about hockey-puck like discs, with a really high