Fuel of the future?

John Mc · May 12, 2013, 06:41:33 PM

Randy -

Here in the Northeast, when sizing a biomass boiler, the best practice is generally to size it for 65-70% of the peak load, rather than 100% of peak. The user then uses supplemental heat (for example their old fuel oil boiler) to make up the difference during peak heating seasons. The reason for this is that biomass boilers just don't have the same "turn down ratio" as fuel oil/propane/natural gas. Even the best designed ones have trouble running at less than about 1/3 load, and some boilers have trouble reaching that.

By sizing for 65-70% of peak, they actually use less of their supplemental heating (running during peak periods only) than they do having a biomass boiler sized for 100% of peak (and losing the ability to heat with it in the spring and fall, when demand is too low for the boiler to run cleanly and reliably.

I've seen some installations with two biomass boilers, one rated for 1/3 load, and the other rated for 2/3 peak load. They fire up the smaller boiler in the fall, switch to the larger when demand dictates, and then run both when the really cold days hit.

These were large, commercial operations with several million BTUs of boiler capacity (so it was easier to justify a dual set-up). They also had automatic flame sensing and relighting, automated ash handling/removal systems, turbulators in the tubes to maximize heat transfer.

It's a bit trickier with a residential installation, but at least in the climate we have in my area, if you are looking to maximize the use of bio-fuels, without constantly having to relight and tinker to keep things running, you'd size the boiler for about 2/3 of peak load, and find another way to make up the extra needed for the peak. Biomass boilers just don't like to stop and start, or run a significantly reduced output. They are less efficient, and tend to burn a lot dirtier under these conditions. They really do like to run in the higher end of their output range.

Richard PM · May 13, 2013, 07:51:38 AM

Come and see it run in Bangor,Maine May 17th and 18th, I'm running it right now on the side of route 111 in Lyman, Me. on a mix of about 60% softwood / 40% hardwood, trees were killed last week so they are green. I have 1- 100,000 BTU water to air heat exchanger on it,( not much heat load at all ) My feed rate is at 80% and the air is at 1/4 inch,( you adjust both to heat load and fuel quality very easily ) we do have fire tube heat exchangers, 3 pass, with turbulators, exhaust temp 320 degrees at the breech with water temp of 190 degrees. We have a timer on it to keep the head hot enough to relight itself and in the event it does go out it is very simple to relight with a torch and causes no trouble with the unit. I will also have one of my pre- plumbed water to water heat exchangers for people to see as I have been asked here before to post pictures here so that others may use the design on their own install. See you all in Bangor.
Richard @ PM

thecfarm · May 13, 2013, 08:07:58 AM

Richard,I'm on my way outside finally.I could read through the past posts,but what is the name of your business? I would like to see you in Bangor.

Richard PM · May 13, 2013, 09:45:26 AM

The name of the company is Portage and Main and we will be at outside booth B-9 in Bass park, Bangor,Me. logging expo May 17-18th. If I may again do so I will post the website for those interested but not able to come to the show as it will have other shows listed that may be closer. The Website is www.portageandmainboilers.com Thank you moderators for allowing me to answer these questions on the forum and if I am going too far let me know. As for the people who are so interested, thank you as well and lets keep burning wood not oil, in the notheast at least. Richard@ PM

Richard PM · May 24, 2013, 08:48:26 AM

GREAT NEWS yesterday the state of Massachusetts approved the sale of our Enviro 500 wood chip boiler ahead of the federal EPA, as a celebration we will be offering a sale on the Enviro 500 to Mass residents and would like your help in finding shows to burn our unit at as a demonstation. Any ideas would be appreciated as we have been waiting far to long at the federal level.
Richard@PM

SwampDonkey · January 20, 2014, 06:17:01 AM

Quote from: SwampDonkey on May 10, 2013, 04:20:02 PM
I'll tell ya one thing, that it's just as much to refurbish them as to build brand new. We rebuilt an albatross at Lepreau, NB and didn't save anything and it still has bugs being worked out. It never helped that the two new generators where dumped into the sea at the docks and had to be sent to Scotland to be overhauled. :

This old relic is still being patched up.

Transporting turbines to Lepreau

AnthonyW · January 22, 2014, 06:00:55 AM

Quote from: Texas Ranger on April 04, 2013, 05:11:02 PM
http://www.economist.com/news/business/21575771-environmental-lunacy-europe-fuel-future

For one person that burns 10 cords per year, I wonder how many trees or acres you would have to own in order to be self sustaining.

For example. My uncle owns a Christmas tree farm. It takes 10 years to grow a Christmas tree to nominal size. He can cut and package 40 acres of trees per year. He owns 400 acres. 10 years*40 acres per year=400 acres. I wonder what the acreage and time for maturity is for doing the same with firewood.

SwampDonkey · January 22, 2014, 06:42:51 AM

Up here we get 0.5-0.7 cord per acre per year of growth. So if you had 20 acres and cut the worst first, since it's firewood, you'd have well and plenty. Most all our good hardwood growing ground around here are now potato fields unless they are too hilly and rough. My firewood supplier has to truck his from crown land loggers and close to 80 miles away.

John Mc · January 22, 2014, 11:16:55 AM

AnthonyW -

Productivity will vary greatly from site to site. I live in the Champlain Valley of VT, just about where the foothills of the Green Mountains start. The former County Forester here generally uses 1/2 cord per acre per year as a conservative number for what can be sustainably harvested off a typical parcel.

On the two parcels where I harvest firewood, we could do that and still be leaving a lot of growth in the remaining trees, so 1/2 cord per acre is not taking ALL the growth.