Seattle Steam Biomass Boiler

[TMonter]

Here is a link of the Seattle Biomass boiler project I'm working on. Our company provided the boiler and fluid bed energy system. Operational date will be this summer 2009.

http://www.youtube.com/watch?v=58GPYuwUFdg

 

[Highbeam]

I read about it in our daily business journal last week. Freaking hilarious how this is considered green and lowering the carbon footprint. 80,000 lbs of biomass a day? Woodburning is even becoming environmentally positive in Seattle! I wonder if it will run during burn bans?

I think it's great. Glad you're involved.

 

[TMonter]

Actually 200 tons per day or 400,000 lb/day not 80,000 lb/day. It is planned to run 24/7-365 and because it is a highly controlled burn it's overall emissions per pound of wood burned is far more efficient than a wood stove. Combustion Efficiency is 99%+ and heat recovery efficiency is in the high 70's.

 

[Redox]

Cool! What are they using for fuel? And how is biomass not "green"?

Chris

 

[TMonter]

Wood fuel will be a mixture of green wood from local sources and sorted urban wood like pallets, clean demolition wood and land clearing like brush.

 

[renewablejohn]

How many kw of electric does the 200 ton per day of woodchip produce.

 

[jebatty]

Combustion Efficiency is 99%+ and heat recovery efficiency is in the high 70’s.

This is about the same specs on gasification boilers for home use. If it can be scaled up and also take green biomass, with variably MC, will be important.

Our local ethanol plant spent megabucks on a gasification steam boiler system that failed and is in litigation. Problem was variably MC and too much biomass reaching the gasification area before it was dry enough to gasify properly. At least that's what I have heard was the main problem. Boiler now sits idle taking up space.

 

[peakbagger]

Check out Chiptec in Vt or Messersmith out of Michigan. They are building and installing wood biomass gasification boilers for schools all over the state of Vermont due to a real good subsidy from the state. They are low pressure, heat only (no electrical generation) units. They are run by the schools janitors and dont require a lot of babysitting as long as they get high grade chips. In a heat only situation, the efficiencies can get real high.

European district heating systems deliver water as low as 120F which allows condensing heat exchagers to be used to recover heat that is normally sent up the stack.

 

[TMonter]

Check out Chiptec in Vt or Messersmith out of Michigan. They are building and installing wood biomass gasification boilers for schools all over the state of Vermont due to a real good subsidy from the state. They are low pressure, heat only (no electrical generation) units. They are run by the schools janitors and dont require a lot of babysitting as long as they get high grade chips. In a heat only situation, the efficiencies can get real high.

Neither of these are true gasifiers though. Messersmith makes inclined grate units and Chiptecs are deitric cell style units but not true gasifiers. Our company has built a couple of these small heating units, the biggest problem around here is training them on the difference between chipped and ground fuels. Not all wood fuel is the same.

How many kw of electric does the 200 ton per day of woodchip produce.

Well Seattle Steam does not make power, but that's sort of a loaded question. Generally speaking it would make 6-8 MW of power dependant on many different factors.

 

[Highbeam]

Cool! What are they using for fuel? And how is biomass not "green"?

Chris

If you ask a typical seattle resident, even the mayor, if burning stumps is green then they would go ballistic. People equate burning wood with smokey chimneys like in marry poppins and think you are evil. Smarter, more educated, city folks will certainly recognize that burning wood is green but those folks are the minority.

I have actually claimed that wood burning is carbon neutral as many here will agree. The dumb tree hugger response was that burning the wood released the carbon much more quickly than if it had been left to rot and buried under forest duff and is therefor not unlike burning petroleum. Ugh.

I wish there was an easy way to burn green wood chips into heat. I have a tractor that can chip a 4" log into chips for such an appliance along with an endless supply of brush from the woodlot.

 

[renewablejohn]

Check out Chiptec in Vt or Messersmith out of Michigan.

How many kw of electric does the 200 ton per day of woodchip produce.

Well Seattle Steam does not make power, but that's sort of a loaded question. Generally speaking it would make 6-8 MW of power dependant on many different factors.

We have a smaller operation using 20 ton per day to generate 600kw of electric from woodchip but are using thermal oil boilers and a steam evaporator to drive conventional steam engines and generators at 150 PSI.

 

[renewablejohn]

Cool! What are they using for fuel? And how is biomass not "green"?

Chris

If you ask a typical seattle resident, even the mayor, if burning stumps is green then they would go ballistic. People equate burning wood with smokey chimneys like in marry poppins and think you are evil. Smarter, more educated, city folks will certainly recognize that burning wood is green but those folks are the minority.

I have actually claimed that wood burning is carbon neutral as many here will agree. The dumb tree hugger response was that burning the wood released the carbon much more quickly than if it had been left to rot and buried under forest duff and is therefor not unlike burning petroleum. Ugh.

I wish there was an easy way to burn green wood chips into heat. I have a tractor that can chip a 4" log into chips for such an appliance along with an endless supply of brush from the woodlot.

We use the brash from the wood to power our CHP unit shredding on site then storing in a polytunnel to reduce moisture content down to 20-30%. We could burn at 50-60% moisture but you lose efficiency and it is better to solar dry to 20-30% moisture. Waste heat from CHP is used to dry woodchip down from 20-30% moisture to 8-12% moisture to enable wood pellets to be made.

 

[Highbeam]

Cool! What are they using for fuel? And how is biomass not "green"?

Chris

If you ask a typical seattle resident, even the mayor, if burning stumps is green then they would go ballistic. People equate burning wood with smokey chimneys like in marry poppins and think you are evil. Smarter, more educated, city folks will certainly recognize that burning wood is green but those folks are the minority.

I have actually claimed that wood burning is carbon neutral as many here will agree. The dumb tree hugger response was that burning the wood released the carbon much more quickly than if it had been left to rot and buried under forest duff and is therefor not unlike burning petroleum. Ugh.

I wish there was an easy way to burn green wood chips into heat. I have a tractor that can chip a 4" log into chips for such an appliance along with an endless supply of brush from the woodlot.

We use the brash from the wood to power our CHP unit shredding on site then storing in a polytunnel to reduce moisture content down to 20-30%. We could burn at 50-60% moisture but you lose efficiency and it is better to solar dry to 20-30% moisture. Waste heat from CHP is used to dry woodchip down from 20-30% moisture to 8-12% moisture to enable wood pellets to be made.

I'm sorry. What's a CHP?

 

[jebatty]

I think CHP = combined heat and power, meaning a system providing steam for heat and steam to drive a turbine for electricity. I suspect the leftover steam energy from the electric power generation is used to provide the heat, thus increasing efficiency, but not sure on this point.

 

[renewablejohn]

CHP is combined heat and power. Steam raised is used in a conventional steam engine to drive a generator the waste steam is then used to provide heating. Efficiency of steam engines is only 10-15% but added to the waste heat utilised of 40% overall efficiency is 50-55%.