Biomass grain dryer?

[Wobblebox]

Just re-evaluating our grain drying and storage, as we currently store quite a lot at 3rd party store, wondering whether it's cost effective to build a new setup with a biomass grain dryer, current storage requirements is around 2000 tons consisting of with 5 crops but will want to future-proof too so would need the scope/capacity to expand current harvest output is around 20-25 t/hr so....

• What type of biomass dryer, ideally would like to fuel it on straw? CF, batch or on-floor?
• Costs
• What would the RHI be?
• Anything else I need to consider

 

[Pieces_of_Eight]

Much more feasible if you're drying low temps, e.g. malting barley.

P!ss wet through feed wheat would need more heat than biomass would give you.

Look at a cash forecast using straw and a zero RHI.

 

[warksfarmer]

Much more feasible if you're drying low temps, e.g. malting barley.

P!ss wet through feed wheat would need more heat than biomass would give you.

Look at a cash forecast using straw and a zero RHI.

Not true. We’ve dried wheat 26% down to 14% with straw biomass. You just need to stir it.

Temperature of air in the tunnel is around 70 degrees from a water temp of 90 degrees. Heat loss in the pipes is minimal over a 200 metre round trip.

 

[Pieces_of_Eight]

I was thinking about a CF system.

 

[warksfarmer]

Just re-evaluating our grain drying and storage, as we currently store quite a lot at 3rd party store, wondering whether it's cost effective to build a new setup with a biomass grain dryer, current storage requirements is around 2000 tons consisting of with 5 crops but will want to future-proof too so would need the scope/capacity to expand current harvest output is around 20-25 t/hr so....

• What type of biomass dryer, ideally would like to fuel it on straw? CF, batch or on-floor?
• Costs
• What would the RHI be?
• Anything else I need to consider

Any biomass boiler straw fed is a bit like a animal in that you can’t just leave it. You’ll need to monitor it bit like a mobile drier really. When it’s working well it’s a breeze. When it’s not it’s a pain. Most of the issues are down to the feeding system used to get the straw into the boiler as it’s a network of shredders and augers which don’t like straw over 15% moisture. Wet spots in bales will cause issues and totally wet bales are a no no.

I think rhi is now about 2p so assuming tier 1 is still in place that would return you just under £27k in rhi. You’d need about 400 tonnes of straw to reach that. However I think they’ve changed the tier 1 and tier 2 levels so double check that.

Don’t forget the elec costs of running a shredder, augers, boiler, and drying system (fan etc) because you’ll be needing around 200amps for that.

And you’ll need to be able to load at least 5 tonnes of straw on unless you want to literally stand by it and constantly monitor it.

Cost wise around £250k for an automated system 1mw boiler installed. Think the kit on its own around £180k if you wanted to do it yourself.

 

[shakerator]

Not true. We’ve dried wheat 26% down to 14% with straw biomass. You just need to stir it.

Temperature of air in the tunnel is around 70 degrees from a water temp of 90 degrees. Heat loss in the pipes is minimal over a 200 metre round trip.

That seems a high temp - I presume that is summer drying ? Do you use a hot water accumulator or just plumbing straight from boiler heat exchanger to fan intake heat exchanger ?

 

[warksfarmer]

That seems a high temp - I presume that is summer drying ? Do you use a hot water accumulator or just plumbing straight from boiler heat exchanger to fan intake heat exchanger ?

High tunnel temp or water temp? You can control the water temp easily by setting the combustion parameters on the boiler. Then with good quality pipe that’s properly installed the heat loss and subsequent tunnel temp isn’t much less. This time of the year tunnel temp would be 55-60 degrees.

We are plumbed direct boiler to heat exchanger.

 

[shakerator]

High tunnel temp or water temp? You can control the water temp easily by setting the combustion parameters on the boiler. Then with good quality pipe that’s properly installed the heat loss and subsequent tunnel temp isn’t much less. This time of the year tunnel temp would be 55-60 degrees.

We are plumbed direct boiler to heat exchanger.

Yes I thought 50c was typical in summer, but depends on size of heat exchanger to tunnel / store volume I suppose.

Do you ever get a problem with the fan overheating?

 

[JCfarmer]

Any biomass boiler straw fed is a bit like a animal in that you can’t just leave it. You’ll need to monitor it bit like a mobile drier really. When it’s working well it’s a breeze. When it’s not it’s a pain. Most of the issues are down to the feeding system used to get the straw into the boiler as it’s a network of shredders and augers which don’t like straw over 15% moisture. Wet spots in bales will cause issues and totally wet bales are a no no.

I think rhi is now about 2p so assuming tier 1 is still in place that would return you just under £27k in rhi. You’d need about 400 tonnes of straw to reach that. However I think they’ve changed the tier 1 and tier 2 levels so double check that.

Don’t forget the elec costs of running a shredder, augers, boiler, and drying system (fan etc) because you’ll be needing around 200amps for that.

And you’ll need to be able to load at least 5 tonnes of straw on unless you want to literally stand by it and constantly monitor it.

Cost wise around £250k for an automated system 1mw boiler installed. Think the kit on its own around £180k if you wanted to do it yourself.

Is £27000 ish your total income from 400t of straw with a value at the moment of about £25000 and then you have the other costs? I appreciate you have the value of heat produced? Doesn't look great though unless I have missed something?

 

[shakerator]

Is £27000 ish your total income from 400t of straw with a value at the moment of about £25000 and then you have the other costs? I appreciate you have the value of heat produced? Doesn't look great though unless I have missed something?

Doesn’t look great ?
Free heat and a higher payment than its market value ....I suppose a lot is down to how “genuine” the heat need is...!

If it’s displacing fossil fuels I think that looks pretty good ... although I agree return on investment depends on the “opportunity costs” above

 

[warksfarmer]

Yes I thought 50c was typical in summer, but depends on size of heat exchanger to tunnel / store volume I suppose.

Do you ever get a problem with the fan overheating?

No never had that. Until you've mentioned it, its never even crossed my mind to be honest.

 

[warksfarmer]

Is £27000 ish your total income from 400t of straw with a value at the moment of about £25000 and then you have the other costs? I appreciate you have the value of heat produced? Doesn't look great though unless I have missed something?

Ok I was guessing a bit before but I've now had a look at the ofgem tariff page and assuming you install a boiler between 200kw and 1MW in size then you'll get 3.05p for tier 1 and 2.14p for tier 2. I can't see that the tier 1 and tier 2 level have altered so assuming tier 1 is still 1314 hours then that would earn you £40,077. If you then did another 1000 hours on tier 2 that would earn you £21,400.

Different straws burn differently to others so to reach tier 1 top level then you need to budget on 3200kwh per tonne so for 1314 hours you need 410 tonnes. However for example OSR straw burns differently to wheat straw which burns differently to barley straw. The heat output varies due to the products but also the moisture content. And then things like year old straw thats barn stored and gone dull burns better then freshly baled straw.

https://www.ofgem.gov.uk/environmen...sources/tariffs-and-payments-non-domestic-rhi

The people that got in early at nearly 6p/kwh for tier 1 back in 2012 will be paid nearly £80,000 compared to your £40,000 above. But when doing it your need to take into account what your saving over your existing system which could be gas or kero? so those costs just disappear. Electricity use will go up because a biomass boiler and associated items will use more than a mobile drier for example. Can you put the heat into a farmhouse as well? You really need somebody to do a proper survey for you.