[Gasification] Tennessee company - pyrolysis biochar + hydrogen ($1.75 per gallon diesel-equivalent?)

Mark Elliott Ludlow mark at ludlow.com
Thu May 15 01:32:17 CDT 2014


Dear Rex,
Not every process is scalable. That's for certain! On this list we look for
sub-optimal, scaled-down approaches. The Haber process is off the radar,
it's obvious. Is there nothing between Here and There? You are the "Go-To"
guy! Speak, Oracle!
Best,
Mark

-----Original Message-----
From: Gasification [mailto:gasification-bounces at lists.bioenergylists.org] On
Behalf Of Rex Zietsman
Sent: Wednesday, May 14, 2014 10:59 PM
To: 'Discussion of biomass pyrolysis and gasification'
Subject: Re: [Gasification] Tennessee company - pyrolysis biochar + hydrogen
($1.75 per gallon diesel-equivalent?)

Art,

You are correct about making hydrogen from methane particularly at the
$4/MMBTU level seen in the USA. However, this is only strictly true on large
scale. At small scale gasification is an order of magnitude cheaper than
steam methane reforming. When I made enquiries about a small (75bpd)
hydrotreater, I was given a rough cost of $10m with a further approximately
$8m for the SMR. Needless to say, I nearly fell off my chair! Some of the
issues were that the design of a hydrogen plant is by its very nature
expensive. Then there are materials of construction - stainless steel. Then
there are the safety aspects that require as much instrumentation as a 2000
bpd plant. One comment I got was "do they make hydrogen compressors that
small?".

Proton Power claim to have a process that produces 65% H2, 30% CO2 and 5% CO
starting at the 250kWe scale. It is a very small step from there via
pressure swing absorption to get 99.9% hydrogen. PSA equipment does exist at
small scale and they have the compressors for compressing syngas. This
should produce hydrogen at the $2/kg level rather than the methane SMR route
of $12/kg.

Kind regards
Rex 

Dr. Karve,

Being able to technically generate hydrogen using incandescent carbon in a
water gas reaction does not make the process economically competitive.
 Typically, the use of incandescent carbon is a batch, cyclic process which
produces pulses of gases which vary in purity over each cycle

Compare the economics of using a batch feedstock which has a variable
composition to one which has a very pure, low cost feedstock (CH4) day in
and day out.  As a process designer, you can readily see that even through
the chemistry works out to generate hydrogen using incandescent carbon, the
day to day practicality of operating a multistage process with such a
variable feedstock is much more difficult and more expensive.

Art,

You make a very valid point, particularly on large scale equipment. However,
down at small scale, you cannot beat the competitiveness of gasification as
a hydrogen producer. It is an order of magnitude less than going the SMR
route using methane. 



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