Grain Drying and Dryers

Dry bulb temp. （℃）

Wet bulb temp. （℃）

Rel

ativ

e h

um

idit

y（

％）

Ab

so

lute

hu

mid

ity

（kg/kg’

）

Dew point temp （℃）

Enthalpy

（kcal/kg’

） Sat

ura

tio

n li

ne

Specific volume （ｍ 3/kg）

Property of Moist Air on Psychrometric Chart

Dry bulb Wet bulb

t1 ℃h1 ％

Grain layer

t2 ℃

t3 ℃h2

％

BurnerFan

A Model of Heated Air Drying

In this case, How dose sate point of air changeon psychrometric chart?

Relationship between palatability and germination

Drying & Quality 1

Relationship between cracking rate of brown rice and percentage of broken of milled rice

Drying & Quality 2

Relationship among Initial moisture content and drying air temperature and drop in germination rate.

Drying & Quality 3

Relationship among Initial moisture content and drying air temperature and serious cracking rate.

Drying & Quality 4

Relationship among Initial moisture content and drying rateand serious cracking rate.

Drying & Quality 5

Relationship among air flow rate and drying rateand serious cracking rate.

Drying & Quality 6

GrainGrain 　　 DryersDryers

Classification grain Classification grain dryersdryers

Batch type dryersBatch type dryers

Continuous type dryersContinuous type dryers

Storage type dryersStorage type dryers

Classification grain dryers 1Classification grain dryers 11.Classification by Aeration temperature

2.Classification by air flow rate

Structure Description Schematic diagram

Flat bed type

The drier which makes itprinciple to dry without

moving grain. Aventilation floor is

horizontal.

Upright type

A basic principle is thesame as the above. But

ventilation floor isvertical. When moisture ishigh, grain may be moved

several times usingthrower

Recirculationtype

While grain is drying,grain is always circulating.

Grain is drying andtempering per 1 cycle.

Uni pass type

While grain is flowingcontinuously from

entrance to exit, grain isdrying.Grain is dried to

goal moisture contents byone pass.

Multi pass type

A basic principle is thesame as the above. Grainis dried to goal moisturecontents by several pass.Grain is storaged in silobetween drying and next

drying.

Grain moving

Static

Batchtype

Moving

Continuoustype

3.Cassification by structure

Classification grain dryers 2Classification grain dryers 2

Grain dryers Grain dryers in facility in facility

(a) Country elevator

(b) Rice center

Continuous type dryer

Batch type dryer

high weight high weight high weightcm kg cm kg cm kg

1.7㎡ 41 370 43 390 45 4203.3㎡ 38 690 40 730 42 7505㎡ 36 980 37 1000 35 960

8.6㎡ 34 1200 31 1100 20 1000Note）a. Paddy density is 550kg/m3 b. Blower power is 0.37kW

Amountof grain

fordryingarea

Blower diameter 48cm 38～35cm 35～32cm

Flat bed type dryer

Burner

Suction blower

Grain

Exhaust air

Heated air

Heated air

Exhaust air

Under screw Rotary valve

Recirculating type dryer 2