New briquette trial

[gensetsteve]

we have a verdo plant near us as well and i was in doing some modifications to some steam lines and the first thing that struck me was the energy input to make pellets and briquettes it sounds simplistic but why chop up logs and chip and compress them to make logs:confused1:

 

Hotmax burns well in our stove. This is made by bedmax and is a waste by product of their main production of horse shavings. So I can see the point in this.

 

Maybe one of the tests should be how much energy does it take to cut softwood into blocks vs compresses bricks and what do you get out of ea.

 

I like the KISS principle and sometimes I think we get to involved looking for a solution to a problem that does not actually exist but does have a grant attached to it.

[woodworm]

Ok a few answers.

 

Wood pellets/Briquettes = 4800kwh/t

Torrefied wood = 6800 kwh/t

 

 

We are not chopping/grinding up wood to then compact it into briquettes/chips, but are making use of the raw material produced by guys like you who have chippers and from waste materials from sawmills, all of which has already been chopped up by you guys and the mills for ease of handling.

Dont knock it, it will give a value to your current waste material !!

 

Our product has been through the carbon calculator designed for HM Government and comes through with flying colours.

 

Torrefction is an auto thermal process. The gases released from the biomass during the torrefaction process are used as a source of fuel in the gas burner, so no fossil fuels are burned in the drying process. These gases are no longer in the manufactured product so they are not released to atmosphere during combustion making it a cleaner burning fuel.

 

We then densify the product into either briquette or pellet form to increase the density of the fuel making transport more efficient, ie more kwh per lorry load. You therefore need less of it to produce the same amount of heat so you can either get more energy into you existing store (fewer deliveries) or have a smaller store for the same amount of energy.

Edited December 13, 2015 by woodworm

[gensetsteve]

Ok a few answers.

 

Wood pellets/Briquettes = 4800kwh/t

Torrefied wood = 6800 kwh/t

 

 

We are not chopping/grinding up wood to then compact it into briquettes/chips, but are making use of the raw material produced by guys like you who have chippers and from waste materials from sawmills, all of which has already been chopped up by you guys and the mills for ease of handling.

Dont knock it, it will give a value to your current waste material !!

 

Our product has been through the carbon calculator designed for HM Government and comes through with flying colours.

 

Torrefction is an auto thermal process. The gases released from the biomass during the torrefaction process are used as a source of fuel in the gas burner, so no fossil fuels are burned in the drying process. These gases are no longer in the manufactured product so they are not released to atmosphere during combustion making it a cleaner burning fuel.

 

We then densify the product into either briquette or pellet form to increases the density of the fuel making transport more efficient, ie more kwh per lorry load. You therefore need less of it to produce the same amount of heat so you can either get more energy into you existing store (fewer deliveries) or have a smaller store for the same amount of energy.

 

Not trying to knock the use of waste for heat but that's not what Verdo do. I have one of these biomass plants up the road would they be interested in our dry fine sawdust or are they likely to have a gate fee

[openspaceman]

Ok a few answers.

 

Wood pellets/Briquettes = 4800kwh/t

Torrefied wood = 6800 kwh/t

 

Are these the gross calorific values of the briquetes per tonne?

 

I think we reckoned on 2.5% of the thermal output was needed in the pelletting, but of course this was electrical power which is "costs" 3 times as much as raw heat. This was on a 5 tonne per hour 300hp press. Some thermal energy was needed to get the sawdust down to 10%mc wwb needed to make good pellets. These energy figures were a small part of the capital and running costs of the facility.

 

 

 

Torrefction is an auto thermal process. The gases released from the biomass during the torrefaction process are used as a source of fuel in the gas burner, so no fossil fuels are burned in the drying process. These gases are no longer in the manufactured product so they are not released to atmosphere during combustion making it a cleaner burning fuel.

 

 

OK you have done well to do this, perceived wisdom was to burn the low cv gases given off they needed to contain 2MJ/m3 , below this even with a sophisticated vortex burner they needed a support fuel to sustain a flame.

 

 

We then densify the product into either briquette or pellet form to increase the density of the fuel making transport more efficient, ie more kwh per lorry load. You therefore need less of it to produce the same amount of heat so you can either get more energy into you existing store (fewer deliveries) or have a smaller store for the same amount of energy.

 

Yes the main advantage of this would be in shipping the product long distances, unlike bone dry wood which is hydrophilic torrefied wood also resists moisture (a product for absorbing oil spills on water used this effect as at the same time as resisting water it increased it's affinity for oil). This has advantages for bulk storage in the open where heaps of woodchip absorbs all the rain.

 

On paper it looks like it would pay to heat the biomass to around 150C, at which stage the lignin has become plasticised and compress it then. The power needed to crush the cell walls is 50% less at this plastic stage. The advantage in the slightly higher temperature being the elimination of that last 10% of water and the loss of the higher oxygen containing compounds to increase the energy in the remainder.

 

It must be fine temperature control to prevent the onset of full pyrolysis whilst getting an offgas of sufficiently high cv to self sustain the process without loss too much loss of too much energy from the raw materials.

[iana]

Thanks for the link interesting process

[woodworm]

Are these the gross calorific values of the briquetes per tonne?

 

I think we reckoned on 2.5% of the thermal output was needed in the pelletting, but of course this was electrical power which is "costs" 3 times as much as raw heat. This was on a 5 tonne per hour 300hp press. Some thermal energy was needed to get the sawdust down to 10%mc wwb needed to make good pellets. These energy figures were a small part of the capital and running costs of the facility.

 

 

 

OK you have done well to do this, perceived wisdom was to burn the low cv gases given off they needed to contain 2MJ/m3 , below this even with a sophisticated vortex burner they needed a support fuel to sustain a flame.

 

 

 

Yes the main advantage of this would be in shipping the product long distances, unlike bone dry wood which is hydrophilic torrefied wood also resists moisture (a product for absorbing oil spills on water used this effect as at the same time as resisting water it increased it's affinity for oil). This has advantages for bulk storage in the open where heaps of woodchip absorbs all the rain.

 

On paper it looks like it would pay to heat the biomass to around 150C, at which stage the lignin has become plasticised and compress it then. The power needed to crush the cell walls is 50% less at this plastic stage. The advantage in the slightly higher temperature being the elimination of that last 10% of water and the loss of the higher oxygen containing compounds to increase the energy in the remainder.

 

It must be fine temperature control to prevent the onset of full pyrolysis whilst getting an offgas of sufficiently high cv to self sustain the process without loss too much loss of too much energy from the raw materials.

 

 

Openspaceman

 

Yes they are per tonne and they are GCV.

 

No support fuel is required after the biomass is up to temperature from start up. (approx 3/4 hour)

 

We heat to a very tightly controlled temperature but not as high as pyrolysis.

 

Your last paragraph is correct.

[aesmith]

Since this process actually remove s energy from the source biomass, the increased energy per ton must be just because it's become lighter as well. Or have I missed something?

[woodworm]

Since this process actually remove s energy from the source biomass, the increased energy per ton must be just because it's become lighter as well. Or have I missed something?

 

 

During the torrefaction process you lose 30% of the mass but only 10% of the energy.

You are removing almost all of the moisture (<2%mc)

[slim reaper]

I am not saying bricks are no good all wood burners are different could just be my set up.

 

I used to burn two year seasoned beech. But currently burn 3x2 softwood off cuts the top flap is shut and bottom cracked open on our hunter. The heat out put is better but it does burn about a third quicker. With beech I used empty the ash pan every two to three days now it's over a week.

 

When changing from a dense hard wood to soft wood it takes a bit of time to get the confidence to shut the flaps down.

Dont know which hunter you have but doesn't closing the top flaps deny the burning process secondary air making it less efficient?

[gensetsteve]

Dont know which hunter you have but doesn't closing the top flaps deny the burning process secondary air making it less efficient?

 

It's a small 5 kw hunter. You could be right if I burn hard wood I crack it open about an eight of an inch. From experience we seem to get most heat and log life with it shut especially if it's windy. I will try a few more experiments