log gasification boiler

Deodar

I am thinking of getting a wood gasification boiler installed in my house but how do I secure my wood supply or is it expensive any help welcome?

Evergreen

You have a number of options open to you really

1. The obvious one is that you buy wood from a local supplier. Ask them for a reduction in price becuase you are buying in bulk and they only have to cut the wood to 0.5m lengths.

2. Buy logs from Coilltie or other forestry supplier, then cut it and split it your self. This option is quite a bit cheaper, however, you will need lots of storage space becuase of the amount of logs that come in a load.

If you want to talk to others with systems up and running then send me a PM and I can pass you some numbers and you can talk directly to them yourself.

Doctor_L

Hi,

Some of the cheaper log gasification boilers can only handle logs with moisture content less than 20%. This means having to buy container loads of logs from eastern Europe.

My biomass colleagues at Tipperary Institute advise me that Irish timber can have moisture levels up to 30%

Check the manufacturer specs of the gasification boiler to ensure that it can handle up to 30%.

Some boilers use an Automatic primary and secondary air valve control that is controlled in conjunction with the exhaust fan speed. The O2 meter dictates that opening of these valves, for example wood up to 40% moisture requires more oxygen to burn than wood with moisture as low as 20%.

Liam

reilig

Doctor_L wrote: »

Hi,

Some of the cheaper log gasification boilers can only handle logs with moisture content less than 20%. This means having to buy container loads of logs from eastern Europe.

My biomass colleagues at Tipperary Institute advise me that Irish timber can have moisture levels up to 30%

Check the manufacturer specs of the gasification boiler to ensure that it can handle up to 30%.

Some boilers use an Automatic primary and secondary air valve control that is controlled in conjunction with the exhaust fan speed. The O2 meter dictates that opening of these valves, for example wood up to 40% moisture requires more oxygen to burn than wood with moisture as low as 20%.

Liam

That's not true. I have ash, beech, birch and pine that has been sawn for 18 months. It is in 40cm lengths. I checked it recently with the moisture meter and the pine and birch have levels of 3% to 5% moisture. The ash has no more than 10% moisture and the beech ranged from 9% to 12%. This wood will be suitable for my "cheaper" log gasification boiler. I even fear that the pine and birch are too dry and I will get a low heat return from them.

Wood for the Gasifying boiler needs forward planning. You need to cut trees at least 18 months ahead of when you need them. You should also cut trees in winter when there are no leaves on them and the sap in them is at their lowest level.

IMO, importing timber from Eastern Europe for a log gasifying boiler is a little extreme.

Doctor_L

Hi Reilig,

Good to hear that low levels are being achieved.

As you correctly pointed out forward planning is very important.

Some people unfortunately don't have the patience and I have seen several example where they want to buy the wood and use it as soon as it arrives or shortly afterwards.

If you dry timber out for more than 1 year you will achieve good moisture levels.

Regards

Liam

Evergreen

I agree with both posts on drying timber, felled timber needs to be stacked in an area where lots of air can pass through it for at least 12 months before it can be used.

Boilers with Lambda probes fitted can handle moisture content up to 40%, however, you are better of to aim for 30% or less with the optimum being between 15 and 25%.

If wood gets too dry it can have other consequenses when you burn it, i.e. the creations of hot spots in the burning chamber which can fatigue the boiler plate over time. If you have a boiler with a lambda probe you can adjust the settings to suit, or if you have a cast iron boiler (you loos out on a lot of efficeincy with cast Iron though) then it will not be a problem either.