Heating an elevated aerated grain silo.

[thebull]

Hi all. Grain moisture isn’t usually an issue for us in Aus. Generally our biggest problem is cooling the grain for pest control in medium term storage.
however this year we need to pull the moisture down 2 percent first and the day time temperatures are not playing the game to do any ambient drying.
our silos are 400m3 elevated cone bottom with 3 high flow aeration fans.
we have a heating fan already for the workshop that has plenty of output but I’ll need to cool the air to < 55 degrees at the intake fans so I don’t cook the grain.
I’m thinking of running the heater into a long steel box to mix the hot air with fresh air. (Heat out out at the cowling is 300deg and the draw for of the intake fans far exceeds to output of the heater). The aeration fans would then draw the air to silo via high temp ducting.
Has anyone done anything along these lines? Am I on the right track?
Thanks all. I hope the spicy cough takes its foot of your collective necks before too long.

 

[solo]

Drying grain here in an on floor store with a large fan and underfloor ducts is possible with ambient air, but it takes weeks due to the humidity. Sometimes heaters are used, but ideally they are used with a thermostat or humidistat so you don’t over dry the grain.The aim is to modulate the burners to save fuel as well as overdrying. It is common to find the bottom at 13% and the top 16% or more. It takes time to move the front of moist air up through the bin. If you don’t have enough air flow the moisture will condense on the grain surface causing spoilage.
This is the sort of systems used in the Uk. http://www.bennettcropstorage.co.uk/modulatory-gas-burners/

 

[Wisconsonian]

In the US, maize/corn and soybeans would commonly be dried that way if they come out of the field within 2%. The bin would be on a concrete slab with an aerated floor, so halfway between an elevated bin and a floor bin. The corn and beans will come off late in the fall so cooling will be enough and they can be dried as the weather permits. Burners would only be used if needed because of continuing unseasonably warm humid weather, or higher moisture levels than 2% over.

Is the grain stable with air through it, and you could possibly wait for higher temps or lower humidity to bring the moisture down? not a lot of wheat around here, so I don't exactly know how farmers handle damp grain in the summer conditions.

 

[snipe]

Hi all. Grain moisture isn’t usually an issue for us in Aus. Generally our biggest problem is cooling the grain for pest control in medium term storage.
however this year we need to pull the moisture down 2 percent first and the day time temperatures are not playing the game to do any ambient drying.
our silos are 400m3 elevated cone bottom with 3 high flow aeration fans.
we have a heating fan already for the workshop that has plenty of output but I’ll need to cool the air to < 55 degrees at the intake fans so I don’t cook the grain.
I’m thinking of running the heater into a long steel box to mix the hot air with fresh air. (Heat out out at the cowling is 300deg and the draw for of the intake fans far exceeds to output of the heater). The aeration fans would then draw the air to silo via high temp ducting.
Has anyone done anything along these lines? Am I on the right track?
Thanks all. I hope the spicy cough takes its foot of your collective necks before too long.

What are the day time temperatures and humidity at the moment?

 

[Brisel]

What are the day time temperatures and humidity at the moment?

This. Why spend all that effort and expense to lower the relative humidity then waste the heat? If the fan capacity exceeds the heater’s then just blowing hot air into the intake would be enough. Start without the box and use probes to measure the temperature further down. The fans will mix the air enough. Where are you in Oz?

As @solo said, you need to dry it slowly so you don’t risk capping the surface.