Wood Chip or Logs for Biomass Boiler?

[renewablejohn]

Now I'm interested. Got any pictures of your system?

Yes thanks but they will not be published. If you have a niche technology that gives you a market edge then why would you want to lose it. Did look at putting a patent on it and sell under licence but was advised the technology is so simple any back street engineer could copy it and flood the market.
To be honest the technology is not rocket science and I cribbed most of it from the high temperature solar kilns found on Australian web sites.

This was my starting point

http://www.nukor.co.za/manufacturers/solar-dryers/20m3-solar-timber-kilns-sg20.html

 

[multi power]

Now I'm interested. Got any pictures of your system?

I would forget burning wood to dry logs, use car tyres to burn and sell all the logs

 

[wilber]

Yes thanks but they will not be published. If you have a niche technology that gives you a market edge then why would you want to lose it. Did look at putting a patent on it and sell under licence but was advised the technology is so simple any back street engineer could copy it and flood the market.
To be honest the technology is not rocket science and I cribbed most of it from the high temperature solar kilns found on Australian web sites.

This was my starting point

http://www.nukor.co.za/manufacturers/solar-dryers/20m3-solar-timber-kilns-sg20.html

I looked at solar thermal for heating our house, didnt seem worthwhile. Out of interest how much does a solar kiln earn you in RHI per year?

 

[renewablejohn]

I looked at solar thermal for heating our house, didnt seem worthwhile. Out of interest how much does a solar kiln earn you in RHI per year?

Works out at approx £10 m3 plus I can sell my logs at a premium price because there "kiln" dried. Its totally wrong because well seasoned timber will be at a similar moisture content to "kiln" dried but then there's lots of cowboys selling "seasoned" timber fresh from the wood.

 

[ringi]

John,

I assume that is £10 per year per m^3 of logs produced not per m^3 of kiln size.

How much of the year do you have enough sun to use the solar kiln?

How long does it take to dry your logs at different times of the year in the solar kiln?

How much electrical power do your solar kilns use? (As I understand it at a lower temperature more air movement is needed.)

Do you use the “not burning wood to dry wood” as a selling point?

Sorry to ask so many questions in one go…..

 

[renewablejohn]

Yes works out approx £10 per m3 sold. Use kiln all year round on weekly cycle. Who says its lower temperature. These kilns are high temperature insulated. Electric use under 500w. We do use the phrase "solar kiln dried" but dont exploit the not burning wood to dry wood.

 

[ringi]

Thanks,

That’s impressive getting a high temperature from solar thermal in winter, given how low the sun is and the thermal loses from the panels. (Hence I think PV is a better option for DHW.) By high temperature I assume you mean over 50c.

Shame you have to use water to move heat so as to get RHI payments, otherwise both wood powered and sun powered system could have lower loses.

Did you have any planning issues with mounting the panels on the ground as well as the top of your containers, so as to get enough heat in winter?

Is that a week to dry the wood from “green” or are you first putting it in your poly tunnel to do the first stage of the drying?

I find the design of the boiler heated kilns so primitive in that they don’t even use MVHR, it as if they are designed to use as much heat as they can getaway with…..

 

[renewablejohn]

Its not impressive its what evac solar tubes do. Look up high temperature solar tubes in particular stagnation temperatures. As for planning why do you need ground mounted panels there is more than one surface on a high cube container than just the roof.
The week is for drying from green if a cloudy week then container emptied at the end of the cycle of IBC's and stacked in drying polytunnel to finish.

 

[ringi]

Firstly some notes to others:

You don’t need to have a single boiler over 200KW (to get the better RHI rate), you can combine boilers into a system, so for example a cheap Farm2000 type boiler along with a modem boiler that uses 50% less wood to give the same useful heat output.

Large (300KW) wood chip boilers seem to be a lot more forgiving on the MC of the wood chip and the size of the chips; they also have automatic ash removal systems etc.

The best setup is if you need the peak output for heating of buildings, but can outside of the few coldest days in the year use some of the boiler output to dry your logs. That way the capital costs is covered by the building heating.

 

[ringi]

John,

Customers expect kilm dried logs to be below 20% mc, e.g. for there not to be a single bit of wood in the bag where if split and measured in the centre the mc is over 20%. I don’t think you are getting this with the wood you dry in the winter and finish in your drying polytunnel, unless it remains in the drying polytunnel for a long time.

This defeats the concept of being able to buy green wood 1 or 2 weeks in advance of selling the split logs to the customers as kiln dried.

However I think you have a very nice system for producing “well seasoned” logs all year round without having to have one year’s worth of timber in stock drying.

If you are also delivering the logs to the customers, hence have less time to process fire wood in winter, then having a lower output in winter and storing say 50% of your yearly sales makes a lot of sense.

PS, Do you get issues with needing a heat dump to stop your tubes overheating in summer?

 

[Doing it for the kids]

Firstly some notes to others:

You don’t need to have a single boiler over 200KW (to get the better RHI rate), you can combine boilers into a system, so for example a cheap Farm2000 type boiler along with a modem boiler that uses 50% less wood to give the same useful heat output.

Large (300KW) wood chip boilers seem to be a lot more forgiving on the MC of the wood chip and the size of the chips; they also have automatic ash removal systems etc..

Out of pure curiosity what boilers out there can burn logs like a farm 2000 style but 50% more efficient?

 

[ringi]

Out of pure curiosity what boilers out there can burn logs like a farm 2000 style but 50% more efficient?

Assuming the logs are well seasoned and ideally split, a “standard” downwards wood gasification log boiler would do so. Normal boilers have a lot less water in them, as well as burning all the smoke, and letting a lot less of the heat go up the flue. Automatic Lambda-Control also sets the correct amount of air going into each part of the boiler, so there is a lot less skill needed to get a good burn.

However they can’t take all shapes of bit of odd wood you may have and no “modem” gasification log boiler is as forgiving as an oversized steel tube wrapped in water.

Look at something like a HDG Turbotec or HDG Euro.

It likes comparing the MPG on a Massey Ferguson tractor and a modem car while driving on normal roads taking the children to school……

It is a real shame that there is not a wood gasification boiler with a loading door and chamber as large as a farm 2000 style boiler. A 2000 style boiler cannot get hot enough for full gasification, as it does not have enough insulation on the inside of the loading chamber. The gas also needs to be burned in a 2nd chamber to get good control, ideally with the 2nd camber operating at over 800c!

 

[renewablejohn]

John,

Customers expect kilm dried logs to be below 20% mc, e.g. for there not to be a single bit of wood in the bag where if split and measured in the centre the mc is over 20%. I don’t think you are getting this with the wood you dry in the winter and finish in your drying polytunnel, unless it remains in the drying polytunnel for a long time.

This defeats the concept of being able to buy green wood 1 or 2 weeks in advance of selling the split logs to the customers as kiln dried.

However I think you have a very nice system for producing “well seasoned” logs all year round without having to have one year’s worth of timber in stock drying.

If you are also delivering the logs to the customers, hence have less time to process fire wood in winter, then having a lower output in winter and storing say 50% of your yearly sales makes a lot of sense.

PS, Do you get issues with needing a heat dump to stop your tubes overheating in summer?

You can think all you like but all my logs go out with a guarantee of less than 20% MC. I do not need to advertise as my logs sell by word of mouth. We do not need to process green timber in the winter as the stockpile of oversize timber which was billeted in the summer and seasoned is processed direct into saleable stock during the winter. Delivery is all by IBC containers on tractor forks so no double handling.
No issues with overheating thats why you have control systems to monitor temperatures.

 

[ringi]

We do not need to process green timber in the winter

That explains why a solor power kiln can work for you, I have no problem in understanding how they can get hot enough for at least 8 months of the year.

No issues with overheating thats why you have control systems to monitor temperatures.

I was more thinking of the tubes overheating and boiling the water and/or downgrading the antifreeze, including if you get a power cut and your heat removal fan fails. Just stopping solder melting could be hard…. Unless you are using a drain back type system.

Your control system must have been hard to optimise, as more veneration will cool the kilm but lead to more RHI payments. Just the trade of between lower RH or higher temperature when you don’t know how much heat input you will get in the next hour must be hard.

 

[Doing it for the kids]

Assuming the logs are well seasoned and ideally split, a “standard” downwards wood gasification log boiler would do so. Normal boilers have a lot less water in them, as well as burning all the smoke, and letting a lot less of the heat go up the flue. Automatic Lambda-Control also sets the correct amount of air going into each part of the boiler, so there is a lot less skill needed to get a good burn.

However they can’t take all shapes of bit of odd wood you may have and no “modem” gasification log boiler is as forgiving as an oversized steel tube wrapped in water.

Look at something like a HDG Turbotec or HDG Euro.

It likes comparing the MPG on a Massey Ferguson tractor and a modem car while driving on normal roads taking the children to school……

It is a real shame that there is not a wood gasification boiler with a loading door and chamber as large as a farm 2000 style boiler. A 2000 style boiler cannot get hot enough for full gasification, as it does not have enough insulation on the inside of the loading chamber. The gas also needs to be burned in a 2nd chamber to get good control, ideally with the 2nd camber operating at over 800c!

Take all this on board and not disagreeing with what you say, apart from the 50% improvement on efficiency part. How efficient are your best boilers burning timber then!?

 

[renewablejohn]

That explains why a solor power kiln can work for you, I have no problem in understanding how they can get hot enough for at least 8 months of the year.



I was more thinking of the tubes overheating and boiling the water and/or downgrading the antifreeze, including if you get a power cut and your heat removal fan fails. Just stopping solder melting could be hard…. Unless you are using a drain back type system.

Your control system must have been hard to optimise, as more veneration will cool the kilm but lead to more RHI payments. Just the trade of between lower RH or higher temperature when you don’t know how much heat input you will get in the next hour must be hard.

This is a commercial process heating system not a cobbled together domestic solar system. Unlike some where not here to optimise the RHI any RHI is an added bonus.

 

[PV & Biomass since 2002]

I've had a quote of £155k for a 990kw Binder with chip hopper etc.
Is that a good deal in your opinion? I just thought it seemed expensive compared to the Heateco.

Did you do the project - how did you get on?

 

[Thick Farmer]

Did you do the project - how did you get on?

Yes. A bit of a steep learning curve but got it sorted in the end.

 

[d williams]

I'm looking at installing a large biomass boiler for drying firewood or wood chip.
How big is the woodland you have as a fuel source
Because unless you have a very good rhi I think you make more money moving your wood fuel on to someone who has a boiler that needs feeding
I'm currently considering either a Heateco 998Kw wood chip fuelled boiler or a similar sized Unical log fuelled boiler.

I've had a few quotes from others (Froling, Binder etc.) but they seem to be a heck of a lot more money.

I realise that wood chip will negate the need for constantly feeding the boiler. However, I only intend running it when we are around during the day and able to move wood in and out of the drying area. I also have a large area of woodland to clear and thought it might be easier to cut it into long lengths (whatever will fit in the burner really) rather than chipping it.

Has anyone got any comments on the pros and cons of each system?

Also, is anyone running a Heateco of a Unical boiler and if so what is your experience of it?

Thanks.

 

[PV & Biomass since 2002]

Yes. A bit of a steep learning curve but got it sorted in the end.

Are you happy with the servicing side? Shout if you need support [email protected]