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:[email protected]] 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. --- This email is free from viruses and malware because avast! Antivirus protection is active. http://www.avast.com _______________________________________________ Gasification mailing list to Send a Message to the list, use the email address [email protected] to UNSUBSCRIBE or Change your List Settings use the web page http://lists.bioenergylists.org/mailman/listinfo/gasification_lists.bioenerg ylists.org for more Gasifiers, News and Information see our web site: http://gasifiers.bioenergylists.org/ _______________________________________________ Gasification mailing list to Send a Message to the list, use the email address [email protected] to UNSUBSCRIBE or Change your List Settings use the web page http://lists.bioenergylists.org/mailman/listinfo/gasification_lists.bioenergylists.org for more Gasifiers, News and Information see our web site: http://gasifiers.bioenergylists.org/
