Grain Systems PNEG-1851 - Manual (Page 81)

Appendix A: Grain Drying Operations
To decide which drying operation is better suited to your needs, a good grasp of the benefits and shortcom-
ings of each operation is required (see the following table). Furthermore, considering that the main differ-
ence between the two is in the physical location of where the grain cooling process takes place, a general
understanding of this important step in the grain drying process is also recommended (see
A Glance at
Cooling Processes, page 82 ).
Table A-4 Advantages and disadvantages of the full-heat drying operation
Advantages Disadvantages
• Allows you to simply dry the grain and then trans-
fer it to a dedicated bin for cooling. As a result,
the hot grain can be cooled at a slower rate,
thereby saving on energy costs and improving
grain quality.
• Increases drying capacity by allowing more bush-
els per hour to flow through the dryer.
• Increases dryer fuel efficiency as the grain is only
dried, not cooled and therefore spends less time
in the dryer. The hot grain can be transferred to
the cooling bin at a moisture content of 1% to 3%
above its target moisture level.
• Allows you to stage the drying process in a multi-
fan configuration; that is, set higher drying tem-
peratures in the top plenum and gradually lower
temperatures as you move towards the bottom of
the dryer. Staging the drying temperature is ideal
for wet grain that is very wet.
• Allows you to use slow cooling methods when
cooling the grain and, as a result, greatly benefit
grain quality (see
A Glance at Cooling Processes,
page 82 for more information).
• Not recommended for all types of grain. Full-heat
is mostly used for drying corn.
• Leads to a higher risk of grain spoilage if the
grain is transferred to cooling bins at a moisture
content that is too high. Proper measuring of the
dry grain’s moisture content should be performed
regularly.
• Requires suitable grain handling equipment, a
logical layout of the handling system, and addi-
tional management time, when cooling in dedi-
cated bins.
• Requires the additional cost and management
time associated with transferring hot grain from
the dryer to the cooling bins.
Table A-5 Advantages and disadvantages of the dry and cool drying operation
Advantages Disadvantages
• Can be used for all types of grain.
• Does not require the additional cost and manage-
ment time associated with dedicated cooling bins,
because the grain is dried and cooled entirely
inside the dryer.
• Allows you to transfer dry grain directly to storage
bins, once the grain is dried and cooled to within
10° to 15° of the outside temperature. With corn,
this allows you to use storage bins with no aera-
tion (in winter), if the corn is unloaded with a mois-
ture content of 13%. At 15% moisture, minimal
aeration is required.
• Leads to higher fuel costs because the grain is
dried and then cooled.
• Decreases drying capacity because the grain
spends more time in the dryer, thus reducing
productivity.
• Overdrying of the grain is probable, thus resulting
in lower grain quality. Optional grain inverters
help eliminate the risk of overdrying.
• Leads to a higher risk of kernel damage when
grain is dried and then cooled inside a high-
speed dryer. For certain types of grain, the rapid
transition from hot to cool air might increase the
risk of stress cracks and render the kernel brittle.
PNEG-1851 Vision N2 81