[Stoves] [biochar] Gasifier stove grant (and semi-gasifiers)
Kevin
kchisholm at ca.inter.net
Tue Oct 30 21:36:52 CDT 2012
Dear Ron
----- Original Message -----
From: rongretlarson at comcast.net
To: biochar at yahoogroups.com
Cc: Discussion of biomass cooking stoves
Sent: Tuesday, October 30, 2012 11:15 PM
Subject: Re: [Stoves] [biochar] Gasifier stove grant (and semi-gasifiers)
Kevin etal
The key word in all this is in the CSU diagram - "Pyrolysis" - look up its definition.
#This site https://en.wikipedia.org/wiki/Pyrolysis defines Pyrolysis as:
"Pyrolysis is a thermochemical decomposition of organic material at elevated temperatures without the participation of oxygen.
# while this site: http://www.thefreedictionary.com/pyrolysis defines pyrolysis as:
1. (Chemistry) the application of heat to chemical compounds in order to cause decomposition
2. (Chemistry) chemical decomposition of compounds caused by high temperatures
# I would suggest that teh latter definitions are more appropriate. To support this belief, I would offer the work of Dr. Tom Reed, who has numberous publications analyzing TlUD's where he refers to the "flaming pyrolysis zone"
# Would you not agree that "The essence of pyrolysis is the thermal destruction of an organic compound by heat"?
# I am not sure that i have addressed your point of concern. Please elaborate further, if I have failed to address it.
Best wishes,
Kevin
Ron
------------------------------------------------------------------------------
From: "Kevin" <kchisholm at seaside.ns.ca>
To: biochar at yahoogroups.com, "Discussion of biomass cooking stoves" <stoves at lists.bioenergylists.org>
Sent: Tuesday, October 30, 2012 6:32:13 PM
Subject: Re: [biochar] Gasifier stove grant (and semi-gasifiers)
Dear Paul
----- Original Message -----
From: Paul Anderson
To: Discussion of biomass cooking stoves ; biochar at yahoogroups.com
Sent: Tuesday, October 30, 2012 4:05 PM
Subject: [biochar] Gasifier stove grant (and semi-gasifiers)
Stovers, and Gasifier folks,
Let's give a big round of applause to Colorado State University and also to Envirofit for their strong entry into the world of gasifier cookstoves!!!
One million dollars worth of encouragement for a strong entry is fantastic. Congratulations. Details are at:
http://www.news.colostate.edu/Release/6485
# Interesting article!
The press release states:
“It [semi-gasifier] separates the combustion process into two phases. In the first phase, combustible gasses are released from solid biomass. In the second phase, those combustible gasses are mixed with air and create a secondary flame,” Tryner said.
I think that definition is a good one for "gasifiers" and is certainly how the term has been used for a decade and more regarding cooking stoves.
# I would suggest that a good definition of a "Gasifier" is as follows:
Gasifier: A Gasifier is a device for converting a solid or liquid fuel into a fuel gas.
# There are three main types of "Gasifiers":
1: Retort: A fuel placed in a sealed vessle, with no access to oxygen, and heated with an external source of heat can yield "pyrolysis gases" that can be captured and led away for chemical recovery, purification, for use as a fuel gas elsewhere, etc.
2: Air Blown Gasifier: Air/oxygen is contacted with a solid fuel at a temperature above its ignition point, to initiate pyrolysis and combustion, in the "Reaction Zone", and CO2 and H2O in partially combusted gases are reduced back to CO and H2 by incandescent char in the "Reaction Zone", leaving little to no residual charcoal. An "Air Blown Gasifier" can be characterized by the intentional supply of only "Primary Air", for gasification of the fuel, and with none of the air supplied leaving the gasifier as "products of intended combustion. "
3: Semi-Gasifier: A "Semi-Gasifier" is identical to an "Air Blown Gasifier", EXCEPT that by design, or by operation, it leaves a significant portion of its initial carbon content as an ungasifier char residue.
# A"Gasifier" differs fundamentally from a "Combustor", where a fuel is burned to completion. A "Combustor" can be easily distinguished from a "Gasifier" by the presence of "purposefully added provision for the introduction of secondary air, to a fuel gas intended for combustion to completion."
So I will ask the first question:
Please define the difference between a "semi-gasifier" and a "gasifier" in the terminology used by CSU. (I hope you just drop the "semi-" part.)
# The difference between a "Gasifier" and a "Semi-Gasifier" is that a "Gasifier" converts substantially all the fuel provided into a gas, while a "Semi-Gasifier" converts only part of the supplied fuel to a gas, and leaves behind a significant portion of the carbon energy content of the initial fuel as char which was not gasified..
# Following is a copy of a picture from the website:
http://www.news.colostate.edu/content/photos/Semi%20gasifier%20schematic.jpg
# This is puzzling... they term their device a "Semi-Gasifier Stove", yet
1: It is NOT a semi-gasifier, in that neither in the schematic, nor in their website text, do they acknowledge the production of char.
2: There is clear provision of "secondary air" for the intended combustion of the products of gasification, ie, it is a "combustor". (or stove.)
It should more properly be termed a "Gasifier Stove" in that all the fuel is gasified, with no residual char.
# On the other hand, a TLUD is clearly a "Semi-Gasifier Combustor" (Stove), in that
1: A significant portion of the supplied fuel leaves the system as char
2: There is definite provision for the introduction of secondary air, to burn the products of gasification to completion.
The folks at CSU do GREAT work, and I am sure that their entry into this aspect of improved cookstoves will result is some great benefits.
# I must be missing something here, but aren't they simply re-inventing the pellet stove?"
Best wishes,
Kevin
Paul
Paul S. Anderson, PhD aka "Dr TLUD"
Email: psanders at ilstu.edu Skype: paultlud Phone: +1-309-452-7072
Website: www.drtlud.com
-------- Original Message --------
Subject: Re: you and Hugh and biochar
Date: Tue, 30 Oct 2012 08:23:21 -0600
From: John Field <john.l.field at gmail.com>
To: Paul Anderson <psanders at ilstu.edu>
CC: Hugh McLaughlin <wastemin1 at verizon.net>
However, the general consensus is that only forced-draft gasifier cookstoves deliver remarkably low emissions, whereas natural draft gasifiers tend to be similar or only marginal better than most rocket stove designs. This is an impression reinforced by my own (very limited) work, as well as by the attached recent paper by Abishek Kar of the Surya project. In contrast, the recent paper by Jim Jetter's group is more difficult to interpret, and includes a natural draft gasifier with better high-performance emissions than all other stoves tested, as well as a forced-draft gasifier among the worst performers. Go figure!
On Mon, Oct 29, 2012 at 5:35 PM, John Field <john.l.field at gmail.com> wrote:
Apologies for the lack of communication here- I was away all last week at the ASA-SSSA-CSSA conference. No new stoves/biochar news at the moment; I'm totally preoccupied preparing for my prelim exam for the next several weeks.
Hope you well,
john
On Mon, Oct 29, 2012 at 5:05 PM, Paul Anderson <psanders at ilstu.edu> wrote:
John,
Sorry that you and Hugh did not meet when he was in Boulder last week.
Are there any more developments involving you and stoves and biochar?
Doc
--
Paul S. Anderson, PhD aka "Dr TLUD"
Email: psanders at ilstu.edu Skype: paultlud Phone: +1-309-452-7072
Website: www.drtlud.com
--
Thank you,
John Field
NSF IGERT Fellow, Multidisciplinary Approaches to Sustainable BioEnergy
Department of Mechanical Engineering, Colorado State University
email: john.L.field at colostate.edu
cell: (317) 748-9792
bioenergy-igert.colostate.edu
bioenergyigert.wordpress.com
--
Thank you,
John Field
NSF IGERT Fellow, Multidisciplinary Approaches to Sustainable BioEnergy
Department of Mechanical Engineering, Colorado State University
email: john.L.field at colostate.edu
cell: (317) 748-9792
bioenergy-igert.colostate.edu
bioenergyigert.wordpress.com
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