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Coal Sweetened Biomass

ctyankee

I'd like to get the groups' input on the concept of burning coal and or biomass together in various mixtures.

The industry refers to it as "sweetening" the biomass when 5%-10% coal is added to the fuel stream consisting on material like switch grass, corn stover, and other crop by-products.

I'd like to sample some opinions on the practice. Thanks

1) Does this still fit your preception of renewable energy?

2) Does it advance the cause of renewable energy?

3) Is it a sell-out to the coal industry?

4) Is is pandering to either side of the fence?

5) Tell us what you think...

‹ Zero Emission Coal Fired Energy -- What would you pay? Carbon Offsets - The Great Debate ›

Submitted by ctyankee on Wed, 02/20/2008 - 14:31.

childress
Re: Coal Sweetened Biomass


BTW: If greenhouse warming is the issue, CO2 is CO2 it doesn't care
where it came from. A lb of carbon from wood is the same as coal, oil
or gas. I know you know this already, but others may have different
notions.

True

Not so much

This is a non sequitur. Just because the CO2 doesn't know where it came from does not mean that they are equivalent to the system taken as a whole. There is currently no methodology in use today for taking the the CO2 released from buring coal, oil or gas back underground into the "carbon input pool" it came from.

If I burn a tree for fuel, and I plant a tree for fuel, in 25 or 50 years or so I've 'recaptured' that carbon back to the original pool it came from. Better yet, a biomass crop like Miscanthus that has a rapid turnaround with little man-made input required, where the CO2 released from buring this years crop is recaptured for next years.

That is the fallacy of this argument: CO2 itself is like a coin that's been flipped doesn't know where it came from, however like the person that bet 'heads' and the coin came up tails, it does indeed matter to us.

Why? Well, you release a bunch of CO2 from one pool into the system and it can't go back into that pool, it has to go somewhere else: either by staying in the system or by increase the size of one of the other absorbing pools.

In answer to your questions, there are a significant number of coal-fired plants in the US, and there are more 'on the way' in the planning and building stages. They are not going to be decomissioned at the drop of a hat. Finding ways to make them 'more green' by co-firing biomass is an imperitive half-step to reduce the amount of carbon released from the underground source. Studies have shown that Miscanthus can be co-fired up to 50% with coal in coal-fired power plants.

See photo of Miscanthus bales outside a coal plant in the UK, scroll down to the second 'page':

http://www.renewableenergyworld.com/rea/news/story?id=51557

This is a -good- thing.

Your question revolved around adding a bit of coal to burning biomass; the real brass ring is to get the opposite to happen-- all the existing coal plants to addition in as high a percentage of biomass possible.

--

Commute Suck?  Twike it -- you'll like it!

www.uiuc.edu/goto/twike 


Thu, 04/17/2008 - 13:39

ctyankee
Re: Coal Sweetened Biomass

Cool plant!  It's a pity about the high Si content, rough on the harvesting machinery... oh well.

That's the kind of science that's helpful.  I don't know if it's a solution, but certainly a step in the right direction.

 

I'd bet that slow pyrolysis, and grinding would make this stuff an even more valuable fuel source, yielding some liquid hydrocarbons, and a pulverized coal equivalent.

Remember the easiest & cheapest lb of CO2 to deal with is the one you don't generate!  Bio-carbon displaces fossil carbon, that's all, the coal *is* sequestered carbon, but it took a lot of sunlight with it all those years ago.


Thu, 04/17/2008 - 14:38

Billy345
Re: Coal Sweetened Biomass

 

Well put! The notion of Carbon Neutrality - the cycle
does have merit and should not be dismissed.
The Plant material, be-it wood from a oak or from some other sources
absorbed some percentage of CO2 during it’s life, if during the burning
process, CO2 is released, the cycle will hopefully provide balance vs. burring
Coal that simply does not have the ability to do anything but add to the
problem and “pool” – not to mention the CO2 used in mining the cool or further
the devastation to the areas where the strip-mining is taking place – but that’s
another discussion.

Billy

 

 


Thu, 04/17/2008 - 14:22

Jeff Schultz
Re: Coal Sweetened Biomass

Are you referring to co-generation, liquification or mixing with biomass,

or some other process? As far as utilizing coal particultes to up efficiency, hey why not. Let me know exactly what process you are referring to, so I may better understand the question put forth.


Wed, 02/20/2008 - 17:51

ctyankee
Re: Coal Sweetened Biomass

Hey Jeff, 

This generally refers to mixing the coal in at or near the point of combustion.  The fuel being burned soley for the production of 'heat'/steam.  The heat could be for electricity, process, etc... but that's a different issue.

I'm interested soley form the "renawables" perspective.

The NOx & SOx would be SCR'd or scrubbed as appropriate, and the ash disposed of as clinker/aggregate/landfill or ground as fertilizer...

The goal is energy.  The issue whether the CO2 is sequestered, is open.   Carbon can be positive(open coal), 'neutral'(biomass), or negative(sequestered). 

BTW: If greenhouse warming is the issue, CO2 is CO2 it doesn't care where it came from.  A lb of carbon from wood is the same as coal, oil or gas. I know you know this already, but others may have different notions.


Thu, 02/21/2008 - 09:51