Drying corn on aerated floor anyone?

[farmerfred86]

Stirrers are essential for deep grain. Our strategy is:
1. Fill store and stir for a day or so. This mixes the grain and removes any compaction from grain pushers, etc. so you get uniform air passage.
2. Estimate how long it will take to take out the moisture in the grain. Stop stirrers and dry for that time, or slightly less with stirrers off.
3. Give it a day or two stirring with air off, then measure moisture. If still too high, repeat 2 and 3 until done.
If you omit the stirring in stage 3, you will end up with over dried grain on the bottom if you are using heated air, or in a low humidity ambient condition.
For best effect, study a psychrometric chart and the equilibrium moisture table of your grain.
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This is actually the strategy I have settled on after a few years and discussion with Bill Basford.
Stirrers on for a day and then dry. Stir again if needed but it does take a lot of patience in our 4m stores to wait for the drying front to rise.
I have actually dried in store from 28% and the stirrers give you so much confidence in dealing with it all.
I am always a bit too keen adding heat but I like to know that the system is ready for fog/rain overnight when the humidity rises.

Currently working through 1000t at 17% and expecting the same again before this harvest is over!

 

[Lincsman]

Thank you. Every day is a school day in here

What wisdom can you share when it comes to blowing moist air through a bulk? My education (not a PhD) taught me that 20% or over needs blowing 24/7 regardless of humidity, without adding heat.

Correct, heat would just move water up the heap as the air cannot carry it out as its "over saturated"

 

[Lincsman]

Sorry, I have spent a long time studying drying, and have written a thesis on control of drying. If you stir while drying, you will heat up the heap first before drying, and spend a lot of energy doing so. You will eventually dry the grain, but in the least efficient way possible. Then you will have to cool it down. Since doing my PhD 20 years ago, we have been drying the way I recommend, and it works with least cost.

Batch dryers do nothing but stir and mix.

 

[sjt01]

Batch dryers do nothing but stir and mix.

Batch dryers have a much shallower bed than 2-3 metres of on-floor drying, so the control algorithm is rather different. They will heat the grain to dry it, and normally will have a cooling section.

 

[grass man]

Stirrers are essential for deep grain. Our strategy is:
1. Fill store and stir for a day or so. This mixes the grain and removes any compaction from grain pushers, etc. so you get uniform air passage.
2. Estimate how long it will take to take out the moisture in the grain. Stop stirrers and dry for that time, or slightly less with stirrers off.
3. Give it a day or two stirring with air off, then measure moisture. If still too high, repeat 2 and 3 until done.
If you omit the stirring in stage 3, you will end up with over dried grain on the bottom if you are using heated air, or in a low humidity ambient condition.
For best effect, study a psychrometric chart and the equilibrium moisture table of your grain.
View attachment 978571
View attachment 978572

Nice to see a factual explanation to help in a debate. Have to say I would have agreed with brisel but you have give me something to think about!

 

[yellow belly]

For floor dryers having high enough air flow is essential
Better to dry less area for a shorter time
If the air flow is too low crusting is inevitable
If an area is higher moisture lowering the depth also speeds drying that area particularly with ducted laterals
Flat floor give much better air flow from the same depth of grain

 

[Lincsman]

Batch dryers have a much shallower bed than 2-3 metres of on-floor drying, so the control algorithm is rather different. They will heat the grain to dry it, and normally will have a cooling section.

Batch dryers can be 10M high, the cooling starts when the heating finishes, |IE the burner stops, the last 1% comes out as it cools.

 

[Neddy flanders]

Stirrers are essential for deep grain. Our strategy is:
1. Fill store and stir for a day or so. This mixes the grain and removes any compaction from grain pushers, etc. so you get uniform air passage.
2. Estimate how long it will take to take out the moisture in the grain. Stop stirrers and dry for that time, or slightly less with stirrers off.
3. Give it a day or two stirring with air off, then measure moisture. If still too high, repeat 2 and 3 until done.
If you omit the stirring in stage 3, you will end up with over dried grain on the bottom if you are using heated air, or in a low humidity ambient condition.
For best effect, study a psychrometric chart and the equilibrium moisture table of your grain.
View attachment 978571
View attachment 978572

@sjt01 thanks for the diagram, could you explain it a bit further, 3M deep wheat at 19% for example. what would your strategy be?

As I understand you are suggesting not stirring until you think its dry, then stir and test, but if its not complete, you continue drying?? so why not stir sooner??
also are you advocating heat or not??

 

[sjt01]

@sjt01 thanks for the diagram, could you explain it a bit further, 3M deep wheat at 19% for example. what would your strategy be?

As I understand you are suggesting not stirring until you think its dry, then stir and test, but if its not complete, you continue drying?? so why not stir sooner??
also are you advocating heat or not??

If you stir sooner, you will put dry stuff on top of wet stuff, and the dry will re-absorb the moisture. The way to get moisture out of the heap fastest is to have the wet stuff where the air leaves the grain.

Heat - use the psychrometric chart and the equilibrium moisture table (or look at the tables in the HGCA/AHDB grain storage booklet) to determine if your ambient humidity is adequate to remove the moisture down to the point you need. If it is not, then you need heat.

 

[Grass And Grain]

determine if your ambient humidity is adequate to remove the moisture down to the point you need. If it is not, then you need heat.

Or a dry air generator?

Not certain how they stack up financially against heat.

 

[sjt01]

Or a dry air generator?

Not certain how they stack up financially against heat.

Basically a very efficient heat pump, high capital cost, quite high electric demand, I have not costed against heat sources but they were a thing about 30 years ago, and you do not see them advertised now.

 

[Grass And Grain]

Basically a very efficient heat pump, high capital cost, quite high electric demand, I have not costed against heat sources but they were a thing about 30 years ago, and you do not see them advertised now.

Yes, must not have got poplar for a reason. Either too high purchase cost or running costs.

 

[T Hectares]

If you stir sooner, you will put dry stuff on top of wet stuff, and the dry will re-absorb the moisture. The way to get moisture out of the heap fastest is to have the wet stuff where the air leaves the grain.

Heat - use the psychrometric chart and the equilibrium moisture table (or look at the tables in the HGCA/AHDB grain storage booklet) to determine if your ambient humidity is adequate to remove the moisture down to the point you need. If it is not, then you need heat.

Thanks for the explanation, I’m learning every year since going to on-floor

Another question, if drying say 16 - 18% Wheat would you use gas to correct humidity at night and keep drying 24hrs or turn off overnight and use the drier humidity day time air ??

 

[sjt01]

Thanks for the explanation, I’m learning every year since going to on-floor

Another question, if drying say 16 - 18% Wheat would you use gas to correct humidity at night and keep drying 24hrs or turn off overnight and use the drier humidity day time air ??

If it was July or early August, use low humidity daytime air. Later in the season the humidity will rise as the temperatures fall so I would use heat.

 

[T Hectares]

If it was July or early August, use low humidity daytime air. Later in the season the humidity will rise as the temperatures fall so I would use heat.

Thanks

 

[warksfarmer]

We have a grain store with aerated floor which is blown by two Typhoon fans, its only been used to cool wheat but this year we want to put wheat in it with 16 or17% moisture and attempt to dry it.
we have no heaters so the question is what is the best way regarding heaters etc?
The wheat is usually pushed up about 10ft high!

See attached.

 

[Lincsman]

Thanks for the explanation, I’m learning every year since going to on-floor

Another question, if drying say 16 - 18% Wheat would you use gas to correct humidity at night and keep drying 24hrs or turn off overnight and use the drier humidity day time air ??

Depends how much you have and what fan power, dont forget it will store at 16% and you can dry in April if its still there, blow frost into it on the first opportunity anyway.

 

[T Hectares]

Depends how much you have and what fan power, dont forget it will store at 16% and you can dry in April if its still there, blow frost into it on the first opportunity anyway.

I had some wheat last year that wasn’t quite there by September so left it and finished off in the 20 degree April weather

Sometimes there’s wheat to load out over
winter that needs to be dry !!

 

[Flatlander]

I have bins that hold 300tons of wheat and often dry with just air. As said you must keep the fan running until the drying front reaches and is blown clear of the top. Fans must give provide enough flow or you’ll be dealing with a moldy drying front part way thru your grain. Is difficult to add moisture to wheat if over dried but it’s part of the process to have the bottom over dry If I look In the top of my bins the air flow will stand my hair up straight and then you can feel the humidity. Adding heat extends the range which can be dried but over 20 % I’ll rotate the bin after a week to break up and mix varying moisture loads to balance out the moisture levels. Not a fast process in the later months of the year. Extra combine capacity and patients is sometimes a better option but not always possible. when I left the uk de humidifiers were the rage. What happened to then.? I’ve dried maize wheat and oats thru my dryer at minus ten with a 30% Humidity and the augers are maxed out taking dry grain away compared to plus ten and muggy takes forever.

 

[woody 1]

I have bins that hold 300tons of wheat and often dry with just air. As said you must keep the fan running until the drying front reaches and is blown clear of the top. Fans must give provide enough flow or you’ll be dealing with a moldy drying front part way thru your grain. Is difficult to add moisture to wheat if over dried but it’s part of the process to have the bottom over dry If I look In the top of my bins the air flow will stand my hair up straight and then you can feel the humidity. Adding heat extends the range which can be dried but over 20 % I’ll rotate the bin after a week to break up and mix varying moisture loads to balance out the moisture levels. Not a fast process in the later months of the year. Extra combine capacity and patients is sometimes a better option but not always possible. when I left the uk de humidifiers were the rage. What happened to then.? I’ve dried maize wheat and oats thru my dryer at minus ten with a 30% Humidity and the augers are maxed out taking dry grain away compared to plus ten and muggy takes forever.

Sorry, I have spent a long time studying drying, and have written a thesis on control of drying. If you stir while drying, you will heat up the heap first before drying, and spend a lot of energy doing so. You will eventually dry the grain, but in the least efficient way possible. Then you will have to cool it down. Since doing my PhD 20 years ago, we have been drying the way I recommend, and it works with least cost.

Can you (sjt01) or anyone else tell me what the air flow through the grain should be to maximise the drying process and minimise the time spent on the drying floor, I know you can have too much airflow, I have an airflow meter and can set the fan to the correct speed, what ever that should be ?