[Gasification] Emissions fines

[Tom Miles]

Tom,

Don't get Kevin started on definitions of gasification. :-)

Try http://en.wikipedia.org/wiki/Gasification

The plants that received fines do not have gasifiers. The only similarity is that they convert wet wood to steam. They use fluidized bed combustors. They use excess air directly in the fluidized bed of sand. They also burn fuels such as urban wood waste that require acid gas control. An FB combustor allows you to control acid gas directly by adding limestone to the bed to form calcium sulfate or calcium chloride that is removed as a particulate. In a combustor the heat transfer - boiler and convective sections - are integral to the furnace-boiler design. In the Nexterra and other gasifier application the gas is transported from the gasifier to a burner that is in a separate boiler enclosure. (From 1985-1998 Interpretations of the tax code allowed the grate portion of a furnace to be called a gasifier when operated with limited air such that staged combustion within a boiler qualified for a producer gas tax credit. That credit has now expired.)     

It's important to look at the whole system. Nexterra uses a unique proprietary bed design, a low velocity above the bed that reduces particulate, a partial oxidation step to clean up tars between the gasifier and the burner in the boiler. Tar reduction is similar in concept to what other fixed bed suppliers, like PRM and PrimEnergy, have done for years. Combustible gas is transported from the gasifier to a burner in the boiler. The gas fired in the boiler is clean enough to use the ESP for particulate control. The combination of the low NOx precursors from the gasifier and their burner design allows them good CO and NOx control. Comparative data are in the Levelton report.

Tom Miles           


-----Original Message-----
From: gasification-bounces at lists.bioenergylists.org [mailto:gasification-bounces at lists.bioenergylists.org] On Behalf Of linvent at aol.com
Sent: Monday, February 21, 2011 4:05 PM
To: gasification at lists.bioenergylists.org
Subject: Re: [Gasification] Emissions fines

Dear Tom,
      In comparing the Kruger Products installation to the ones which 
received fines, one might be tempted to say that a fixed bed is better 
than a fluidized bed, but one would have to compare emission standards 
between the two jurisdictions to firmly make this claim. The Nexterra 
design has a relatively high tar yield.
      The word gasification in my opinion is still misapplied unless the 
gas can be cleaned and transported across a jurisdictional boundary for 
use, otherwise, it is still a dual stage combustor.
Sincerely,
Leland T. "Tom" Taylor
President
Thermogenics Inc.
www.thermogenics.com
505-463-8422

-----Original Message-----
From: Tom Miles <tmiles at trmiles.com>
To: 'Discussion of biomass pyrolysis and gasification' 
<gasification at lists.bioenergylists.org>
Sent: Sun, Feb 20, 2011 8:24 pm
Subject: Re: [Gasification] Emissions fines

Pulp and Paper Canada (Feb 2011) reporting on a gasifier-boiler 
application: 
http://www.pulpandpapercanada.com/issues/story.aspx?aid=1000402062 
Kruger's Biomass Gasifier Fuels Customers' Need for GreenBiomass 
gasification has quantifiable environmental benefits to show customers: 
fewer GHG emissions, less fossil fuel, better air quality.By: By Tony 
Kryzanowski