Can someone help me understand the difference between 3 stage combustion and dual stage gasification? I saw this presentation that was done for the NYS Research and Development Agency and put out by the EPA that compares the emissions from different type units. The 3 stage combustion unit was a Central Boiler E 2300 and the dual stage gasification unit was an Econoburn EBW 200. Are the combustion characteristics for the 3 stage combustion the same (i.e. high temperature, adequate turbulence and combustion time) as a downdraft gasifyer?
3 stage combustion
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oakmando said:
I think a good indication of what that was worth is the fact that the 2300 has been pulled from the market. 'Nuff said.
Ouch, I'm just trying to understand what the EPA is considering as they go forward with their new NSPS. I really don't get where the heat exchange occurs in these new so called gasification boilers, 3 stage combustion units or whatever. I don't have experience with a lot of units except that I owned a Hardy boiler in the early 90's and it smoked like crazy and now I got a Tarm Excel 2000 that I got in 2008. It took a year or so to get the operation down and get my wood supply so it was sized and dried right, now it works great, smokes a little on start up and full out ofter that until the wood is gone. Used 6 cords last year to heat a 2800 sq. ft. house and 1400 sq. ft. basement! I know this technology works good.
The issue I have, is that EPA certifies Phase 2 wood boilers as being the cleanest, but its not true. Most dual stage gasification systems with remote storage systems can't get EPA certified for a number of reasons mainly as I see it because they are tested using a specific method which is contrary to the methods recommended by gasification unit manufacturers. So, when the govment gives incentives like tax credits, the most efficient units can't get one because they don't have the EPA certification. In addition, there are still consumers out there that trust what the govemnt tells them. EPA's basis for some of these new NSPS standards may be based on limited information including the study that used the E 2300.
Did I hit a nerve or something?
The issue I have, is that EPA certifies Phase 2 wood boilers as being the cleanest, but its not true. Most dual stage gasification systems with remote storage systems can't get EPA certified for a number of reasons mainly as I see it because they are tested using a specific method which is contrary to the methods recommended by gasification unit manufacturers. So, when the govment gives incentives like tax credits, the most efficient units can't get one because they don't have the EPA certification. In addition, there are still consumers out there that trust what the govemnt tells them. EPA's basis for some of these new NSPS standards may be based on limited information including the study that used the E 2300.
Did I hit a nerve or something?
y eoakmando said:
No. I used to be nervous and jerky but I'm not nervous an mor .
Frankly speaking, my advice at this point would be to pretty much ignore the EPA test data until they (hopefully) get their stuff in a pile and come up with an accurate method for assessing what these units actually do.
The test method was primarily directed at outdoor wood burners and I think EPA didn't even realize that the indoor gassers were on the radar. Some of those manufacturers (Econoburn IIRC?) submitted their units for testing under the erroneous protocol used for the OWB's but it was still the same failed test. Their method of testing bears no resemblance to real world use and the testing done by the OWB manufacturers was in nearly every case not worth the paper it's printed on.
I agree 100% with you on the EPA test methods. It makes my head spin with the modifications they introduced to include indoor boilers. They need to scrap it and start over.
Can you help me better understand what the difference is between a so called 3 stage combustion and a dual stage gasification? And why did CB take the E2300 off the market?
I know what my Tarm does. The ceramic tunnel gets cherry red and the gasses burn >1600F and probably closer to 2000F and there is enough turbulence and contact time before the gasses go through the 6 tube heat exchanger. The stack temp is generally 250 to 350F so there seems to be pretty efficient heat transfer.
Can you help me better understand what the difference is between a so called 3 stage combustion and a dual stage gasification? And why did CB take the E2300 off the market?
I know what my Tarm does. The ceramic tunnel gets cherry red and the gasses burn >1600F and probably closer to 2000F and there is enough turbulence and contact time before the gasses go through the 6 tube heat exchanger. The stack temp is generally 250 to 350F so there seems to be pretty efficient heat transfer.
If you search on here for the E classic, you'll find a number of threads about them. In summary, it sounded like CB didn't do a lot of field testing and starting shipping units...and people had to work pretty hard to get them to work. Some of this, if I recall, involved drilling holes in passageways to provide more secondary air, etc. Things like that.
I believe the 2400 is supposed to replace the 2300....no?
There are a couple of other active threads right now discussing EPA certs and testing, efficiencies, etc.
I believe the 2400 is supposed to replace the 2300....no?
There are a couple of other active threads right now discussing EPA certs and testing, efficiencies, etc.
Central is just adding a "step" in the process to make their gasification look different than anyone else. It's on page 6-7 of the pdf for the E-Classic 2400
It appears that they refer to the portion of gasification which releases the smoke and wood gas as a "second step" where normal manufacturers include it as simply part of the whole. It's not actually different than any other gasifier so don't get sucked in by the hype. If in doubt, call the factory up and ask one of their people in tech service what the deal is. While you're at it be sure to ask where the condensate drain is because there must be one seeing as how it is listed at over 90% efficiency.
Getting tired of manufacturers reinventing fire itself........can you tell?
It appears that they refer to the portion of gasification which releases the smoke and wood gas as a "second step" where normal manufacturers include it as simply part of the whole. It's not actually different than any other gasifier so don't get sucked in by the hype. If in doubt, call the factory up and ask one of their people in tech service what the deal is. While you're at it be sure to ask where the condensate drain is because there must be one seeing as how it is listed at over 90% efficiency.
Getting tired of manufacturers reinventing fire itself........can you tell?
Thanks heaterman. It looks like the technology is comparable, they use a fin type heat exchanger instead of tubes, but they don't have remote or integral high volume storage, so they cycle whereas a boiler with storage should run a load without cycling. I don't know how they report over 90% EN 303.5 efficiency when the top 25% of European pellet boilers are reported at slightly above 85% and all less than 90%.
oakmando said:
That is a mystery to me also and exactly what I mean about marketing hype. It defies the limits of physics.
Like the man said.........If it looks to good to be true........
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