Drying wheat below 15% in December

[shakerator]

I have around 100t which is around 15.5-16%. I need to take 1% out. Have a tunnel and wooden floor with laterals blocked off where wheat is dry. How much heat do I need? I'm trying to run fan when 75% humidity and below. I have 2 diesel (indirect) 55kw space heaters, 50hp fan. Is this enough heat to do it in a couple of days? How much would that reduce ambient humidity by? My humidity sensor has packed up.

 

[Richard III]

My guess is you have enough heat, but the variable is the air flow you have through the grain. I would measure the increase in air temperature I was achieving on the other side of the fan, you should be able to work out a rough R.H. from that then. If it is not enough, shut more laterals off until you get the desired temperature rise?

 

[franklin]

Drying wheat today. Humidity is low and burners are on. Havent been many low humidity days, or cool days for cooling yet. Can you still it / hire in a grain butler for a couple of days ?

 

[average farmer]

Coukld you wait a couple weeks? i've noticed the past few years that when the daylight hours start getting longer the humidity starts to drop faster andyou get a lot more drying days.

 

[average farmer]

our fans set at 73% but it only comes on for a hour, maybe 2 on a good day,for the last week or two.

 

[Brisel]

You''ll get quicker drying when the temperatures are higher - reducing humidity is the easy bit. Warmer air can carry more moisture so will mean less fan hours. Search for absolute humidity as well as relative humidity. You need to aim to raise the temperature by at least 5 oC to lower the humidity enough to dry it.

 

[blue power]

Why not sell it as it is and take the penalty, probably work out cheaper

 

[shakerator]

You''ll get quicker drying when the temperatures are higher - reducing humidity is the easy bit. Warmer air can carry more moisture so will mean less fan hours. Search for absolute humidity as well as relative humidity. You need to aim to raise the temperature by at least 5 oC to lower the humidity enough to dry it.

Would these figures be relative or absolute?
http://www.metoffice.gov.uk/mobile/forecast/gcrwgdr98

 

[shakerator]

Why not sell it as it is and take the penalty, probably work out cheaper

Unfortunately on a GP1 contract (next week!) to a certain mill whose claim structure would not render your statement true

 

[shakerator]

You''ll get quicker drying when the temperatures are higher - reducing humidity is the easy bit. Warmer air can carry more moisture so will mean less fan hours. Search for absolute humidity as well as relative humidity. You need to aim to raise the temperature by at least 5 oC to lower the humidity enough to dry it.

Sorry being a bit slow . RH has to be a percentage, absolute is a number. Am I right?

 

[Banana Bar]

Why not sell it as it is and take the penalty, probably work out cheaper

That's what I would do

 

[shakerator]

My guess is you have enough heat, but the variable is the air flow you have through the grain. I would measure the increase in air temperature I was achieving on the other side of the fan, you should be able to work out a rough R.H. from that then. If it is not enough, shut more laterals off until you get the desired temperature rise?

So you would measure temp inside the tunnel or grain bulk temp? I guess the wheat will cool if it's damper than the air coming in

 

[yellow belly]

put a clear plastic u tube with water in it one end in the tunnel one end out about 4 inches difference gives enough air flow for 2 m depth of grain with temperature this low you need 65 RH air to get it dry enough

then test the grain at the bottom to see what moisture you are at if it is over dryied below 14 at the bottom reduce the heat but if it is 14 then dry 2/3 of the depth and it should be ok averaged
I use a spear that collects a small sample on the end of drainage rods so spot sample

if you measure the air intake temperature a 1 degree rise usually takes out 5 points of rh so air at 80 rh needs 4 degree rise for 60 rh air

 

[shakerator]

put a clear plastic u tube with water in it one end in the tunnel one end out about 4 inches difference gives enough air flow for 2 m depth of grain with temperature this low you need 65 RH air to get it dry enough

then test the grain at the bottom to see what moisture you are at if it is over dryied below 14 at the bottom reduce the heat but if it is 14 then dry 2/3 of the depth and it should be ok averaged
I use a spear that collects a small sample on the end of drainage rods so spot sample

if you measure the air intake temperature a 1 degree rise usually takes out 5 points of rh so air at 80 rh needs 4 degree rise for 60 rh air

Excellent advice thankyou . What are your thoughts on grain butler type stirrers and drying speed? Some studies suggest it slows drying by interrupting fronts, but does avoid the costly over dying you refer to

 

[Brisel]

Sorry being a bit slow . RH has to be a percentage, absolute is a number. Am I right?

Yes, that's it. I would argue that warmer air with a higher relative humidity will be better for drying with the aid of a heater to drop RH % than a cold dry day where RH is lower but the total water carrying capacity of the air is lower.

The grain stirring question is a good one. By agitating the bulk you'll still be putting dry air in & getting moist air out, effectively turning the heap into a batch drier. For really wet grain it speeds up drying by preventing too much condensation near the top.

Remember that the dry stuff at the bottom will blend nicely with wetter stuff at the top when you load out so as long as the front is through most of the heap you should be ok. You'll know when the bulk is dry because as you walk over it your feet will sink in on the drier stuff. A wet crust will be like walking over concrete. The danger with leaving wet spots are claims & spoilage though if you keep it cool you'll be ok.

 

[Neddy flanders]

who says its 15.5%? On farm moisture measurement, Merchant testing and end user analysis never come up with the same result.

 

[Brisel]

who says its 15.5%? On farm moisture measurement, Merchant testing and end user analysis never come up with the same result.

Good point. I have had issues with sprouted grains showing 16.5% on various ring calibrated Foss meters yet my trusty old Marconi and some Sinars show 14.4%

 

[Bomber101]

To dry wheat to 14.5% at this time of year you will an RH of 62.5. We have a CHC gas burner rates at 1 million btu to dry grain. This will not be burning all the time but in bursts to keep tunnel RH at around 62.5. 75% humidity will dry, or moisten, corn to around 17% at this time of year, you need to lower rh by a bit more due to less even humidity throughout the day. RH is slower than heat, 0.5% per day, but keeps quality. Gentle heat will lower humidity by raising the moisture carrying capacity of the air. Make sure you remove this warm, moist air from the store otherwise it will condense under the roof and drip on the crop. We have a grain butler to stir crops and it does make a huge difference if corn has compacted layers from a grain pusher. It will stir it all up and remove these layers which slow air flow, or in a worst case scenario, divert air around the pockets of grain that need it the most. We are only drying now due to the fact our old Bentall fan of 40 years died and getting a replacement has taken time, especially frustrating when a second floor store fan died this autumn as well.

 

[Farmer Miggins]

put a clear plastic u tube with water in it one end in the tunnel one end out about 4 inches difference gives enough air flow for 2 m depth of grain with temperature this low you need 65 RH air to get it dry enough

then test the grain at the bottom to see what moisture you are at if it is over dryied below 14 at the bottom reduce the heat but if it is 14 then dry 2/3 of the depth and it should be ok averaged
I use a spear that collects a small sample on the end of drainage rods so spot sample

if you measure the air intake temperature a 1 degree rise usually takes out 5 points of rh so air at 80 rh needs 4 degree rise for 60 rh air

4" back pressure does not necessarily give good airflow, the other bit of kit required is an airflow meter to measure the flow on the top of the heap. If the grain is compacted, has dense spots due to wet patches or is too deep then the manometer will show more than 4". It is a case of balancing the variables to get a good flow, then applying heat to lower RH

 

[Lincsman]

Unfortunately on a GP1 contract (next week!) to a certain mill whose claim structure would not render your statement true

Throw everything at it on half decent days/nights, you may overdry the bottom and stirring would help, but mixing up when loading out should sort it, if starting a new store when its all off the top, load your trailers and hold that back until later.