sawdust and chip burning boilers.

[starmac]

What do you call the boilers that are designed to burn sawdust and chips.
I took a load of logs today to probably the most modern mill in mainland Alaska today. They heat everything with a boiler that burns sawdust and chips, including two large dry kilns. The guy there didn't know what you called it other than a boiler, but gave me a tour of the boiler room. It had a very impressive burnham boiler and a hopper close to 20 feet tall feeding it.
I am just wondering how practical one of these would be on a smaller scale.

[Roger2561]

I know Postage & Main (OWB manufacturer) makes a wood chip boiler but it is mainly for businesses.  It's too big for home use.  The last I knew they do not make a scaled down version for the home owner.  I had looked into it knowing they'll be time when operating a chainsaw will be out of the question.  But, I can operate a tractor with a front end loader so filling a hopper will not be a problem.  My concerns are, how dry do the chips need to be so one is not wasting energy drying it, and, if the chips are too wet, isn't there a risk of the chip pile freezing to the ground or in a large clump, making reloading difficult?  Roger 

[jueston]

http://bioburner.com/

the bioburner is made by the woodmizer people and it looks awesome. they have a youtube channel where they test burning stuff just to show you how diverse it can be. off the top of my head i think they show: fine saw dust, wood chips, pellets, corn, roof shingles(with the top layer removed), dog food(very high energy), and dried manure

when i finally escape the city and build a home i want to install a bioburner to heat it. they have different size hoppers, small ones for inside or you can connect it to a huge silo outside.

[r.man]

I have been around two large industrial boilers and the delivery systems that they use should scale down to an OWB. They are not purely automatic like a gas or oil furnace but are less operator labour intensive than firewood. You need to clean ashes and clinkers and keep everything running. Chip burning furnaces are more common in Europe. Saw a video about a large estate in the UK that was positioning itself as a local provider of domestic burnable chips for households. To me it makes more sense to chip a tree and then burn the chips rather than chip and then pelletize and then burn.

[starmac]

Roger this time of year they are burning green sawdust straight off the mill, automatically gets augered into the hopper or silo I guess you could call it.
There is no chance of the sawdust freeing as the silo is in the same building that houses the boiler and it is plenty warm in there. He told me in the winter when they do not use the mill as much is when they burn chips, and these are stored in a seperate building, so they may be fairly dry before they are augered into the silo.
I do know they sell green chips straight from the landings to two different schools, chipped into a live bottom trailer and delivered to the school, I do not know how much storage these schools have or if the burn them green.

[Al_Smith]

It might be like waste oil burners.They work good but you have to have a source of fuel .

Something to think about .With a waste oil burner,if you owned a large trucking company you'd have a source of old crankcase oil .Same with sawdust if you owned a sawmill .Other wise any more ,at least around here they get paid for it .Horse bedding etc .

Companies get resourceful .Years ago you could get all the corn cobs you wanted for free which fired many a pot bellied  stove .Now if you can even find a cob with the advent of picker shellers they grind them up for sandblasting media etc. The slaughter houses have figured how to use everything on a pig except the oink and they're working on that .

[starmac]

The availability of chips is the reason for my interest. The mill I'm talking about has the only market I know of at all for chips in the whole interior.  After this year I fully expect we will have exactly zero market for pulp in the interior.
We leave an astonishing amount of wood in the woods that just goes to waste, nothing comes out that will not make a 16 foot sawlog, even the one pulp market we had did not want anything shorter than 24 foot, so the amount of wood left to rot is huge.
Just thinking there has to be a way of developing a market for some of it, smaller scale chip burners could possibly be a way.  The new laws against burning any solid fuel here would be a huge damper on trying to develop a local market though.

[John Mc]

Some Eurpoean companies make some good residential sized wood chip boilers. Ingeneral, their wood combustion products are very good (they have to be to meet Eurpoean specs). Unfortunately, I can't recall the brand names at the moment

[svart ole]

About 16 years ago I picked up a large industrial hot water heater that came out of a old hospital. It was more like a vertical boiler. 4 ft in diameter and 6 ft tall. Ended up putting a old coal stoker under it and heated with 3/8" wood pellets and when I could get them green wood chips. Worked very well. My source of bulk wood pellets vaporized and wood chips where hard to get. I needed to run a agitator in the feed bin to keep them from bridging. You also need a smaller chip with no bark strings and that is not easy to find. I still use that setup at my current location but just fire it with 20" split wood. Less problem getting my fuel. Producing and storing a winters worth of wood chips is a lot of time effort and money vs plain firewood. Ya, I know all you need is this and that and it is real easy. Thing is this and that takes a good bit of money to put in place and maintain. The process does not scale down to the home owner level very well. Wood pellets work very well on the other hand and are easier to store and handed and feed in a coal stoker very well. They are now hard to get in bulk and the price is not worth it in my book. Not only that putting up firewood keeps me healthy in my old age.

[DMcCoy]

A guy named Larry Dobson has done some interesting research on the burning of wood even wet wood.
Worth the time to look at his research.