drying and dryer
TRANSCRIPT
Grain Drying and Dryers
Bio-oriented Technology Research Advancement Institution (BRAIN)Institute of Agricultural Machinery (IAM)
Yasuyuki HIDAKA
Agricultural Mechanization for Sustainable Farming System Course 2004
Introduction of IAM 1Introduction of IAM 1Japan
Saitama
Tokyo
Ibaraki
TochigiGunma
Chiba
Kanagawa
Head office
museum
Show room
Introduction of IAM 2Introduction of IAM 2Fundamental Technology Department
Crop Production Machinery and System Department
Horticultural Engineering Department
Animal Industry Engineering Department
Testing and Evaluation Department
Introduction of IAM 3Introduction of IAM 3Testing and Evaluation Department
ROPS Test
Harvester Test
Transplanter Test
Tractor Test
Mono rail Test
IAM Test
OECD Test
Boom sprayer test
Safety Test
National Test
Introduction of IAM 4Introduction of IAM 4
Certificate for safety test
Certificate for national test
Introduction of IAM 5Introduction of IAM 5
http://brain.naro.affrc.go.jp/iam/
Situation of Situation of Post Harvest Post Harvest in Japan 1in Japan 1
Harvest Moisture content 25 %
DryMoisture content 15 %
Transporting to dryer within 4 hours
Artificial Drying 92 %
Drying facility 30 %
Natural Drying
Japanese farmer controlled paddy by moisture contents.
Husk
Individual 62 %
Situation of Situation of Post Harvest Post Harvest in Japan 2in Japan 2
Storage
Distribute
Rough Rice
Brown Rice
Brown Rice
Brown Rice
Milling Factory
Country Elevator
Individual Farmer
Governmental ,JA and Private company’s Warehouse
Distribute
Situation of Situation of Post Harvest Post Harvest in Japan 3in Japan 3
0
2
4
6
8
10
12
14
16
18
0 10 20 30 40 50 60 70 80 90 100 110 120 130
Storage period (hours)
Co
lore
d g
rain
by
mic
roo
rga
nis
m
(%)
(Toyama pref. Agri. Tech. Center, 1997)
Situation of Situation of Post Harvest Post Harvest in Japan 4in Japan 4
-15
-10
-5
0
5
10
15
20
25
30
35
1 2 3 4 5 6 7 8 9 10 11 12
Manth
Temperature (℃)
Harvesting period
Temperature Precipitation
70
90
110
130
150
170
190
210
230
1 2 3 4 5 6 7 8 9 10 11 12
ManthPrecipitation
mm
()
Harvesting period
We need artificial drying.
We have a lot of precipitation in harvesting period.
Temperature is low in harvesting period.
5%
10%
15%
20%
25%
30%
10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
Relative humidity
Eq
uili
bri
um
mo
istu
re c
on
ten
ts (
w.b
.)
10℃
30℃
20℃
Average temperature and humidity range in harvest time of Japan
Equilibrium moisture content (paddy rice)
Situation of Post Harvest in Japan 5Situation of Post Harvest in Japan 5
Grain DryingGrain Drying Calculate amount of remove waterCalculate amount of remove water
Air properties on psychrometric chartAir properties on psychrometric chart
Relationship between temperature andRelationship between temperature and
humidity in thick grain layerhumidity in thick grain layer
Calculate amount of air and heat Calculate amount of air and heat energy using psychrometric chartenergy using psychrometric chart
Drying and qualityDrying and quality
We can know the drying energy by calculating the amount of remove water.
Calculate Amount of Remove WaterCalculate Amount of Remove Water
Weight of dry matter before drying = Weight of dry matter after drying
Total weight( W )
Total weight( W’ )
Dry matter Moisture Dry matter Moisture
Before drying After drying
Mi % Mg %
W× ( 1-Mi/100 )
W’ = ( 1-Mi/100)
( 1-Mg/100)W ×
Amount of remove water = W - W’
W’× ( 1-Mg/100)=
Ww: Weight of remove waterW:Weight of grainMi: Initial moisture contentMg: Goal moisture content
Mg)-(100
Mi)-(100w WWW =
Conclusion
Equation
Practice
Q.1 Calculate amount of remove water when 3000kg paddy (M.C.27%) was dried to 15%.
W = 3000kg
Mi = 27%
Mg = 15%
WW = ( 100-Mi)
( 100-Mg)W ×W -
( 100 - 27)
( 100 - 15)3000 × 3000 -=
= 3000 - 2576
= 424 kg
In this case, We must remove 424 kg water.
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’) S
atu
rati
on
lin
e
Specific volume(m 3/kg)
Property of Moist Air on Psychrometric Chart
Dry bulb Wet bulb
Enthal
py
Relative humidity (%)
Dry bulb temperature (℃ )
Wet
bul
b te
mpe
ratu
re
(℃)
Specific volume
Ab
so
lute
hu
mid
ity
(k
g/k
g’)
Psychrometric Chart
Grain layer
t2 :Temperatureh2 : Humidity
t1 : Temperatureh1 : Humidity
Air-inlet
t1 t2>
h1 h2<
Relationship between temperature and humidity on thick layer
Air-outlet
Dry bulb temp. (℃)R
elat
ive
hum
idity
(%)
Abs
olut
e hu
mid
ity(
kg/kg’)
h1
%
t2
h2 %
H1
t1
H2
Relationship between temperature and humidity on psychrometric chart
(H2-H1)Capacity of absorbable water per 1 kg-air
Humidity is increase when air passes grain layer
Drying process
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?
Dry bulb temp.(℃)
Rel
ativ
e h
um
idit
y(%)
Enthalp
y(kc
al/kg’)
t1 t2
H1
H2
e2
e1
(e2-
e1)
t3
e3
e4Eva
poratio
n late
nt hea
t
Ab
solu
te h
um
idit
y(
kg/k
g’)
rSpecific volume ( m3/kg )
Relationship between temperature and humidity on psychrometric chart in a model
(H2-H1)
h1h2
Capacity of absorbable water per 1 kg-air
Heat e
nergy
require
d for d
ryin
g
Heating process
Drying process
G (kg) = Ww÷(H2-H1)
Q (m3) = G ×r
q (kcal) = G×(e2-e1)
Equation of Amount of Air
Equation of Heat Energy
Conclusion about Drying
Drying Simulation 1
20℃70 %
25℃ 、 75%
42℃
Weight : 500kgM.C. : 24 %
Grain layer
The grain which weight is 500kg dried from 24% to 15% of moisture contents after 8hours.
Q.1 Calculate amount of remove water.
Drying Simulation 2
=500 – 500 ×( 1-0.24 )( 1-0.15 )
We must evaporate 52.8kg water. And we must evaporate 6.6kg per 1hour because drying time 8 hours.
52.8 ÷ 8 = 6.6 ( kg/h)
52.8kg
W = 500kg
Mi = 24%
Mg = 15%
WW = ( 100-Mi)
( 100-Mg)W ×W -
Dry bulb temp. (℃)R
elat
ive
hu
mid
ity(%)
Absolute humidity ( kg/kg’)
Enthal
py(kc
al/k
g’)
Specific volume(m 3/kg)
70%
20 4275
%
0.0102
0.0149
16.1
11
0.0047
0.908
5.1
25
Drying Simulation 3Q.2 Read differences of absolute humidity and enthalpy from psychrometric chart.
Drying Simulation 4
Q.3 Calculate amount of air.
G = Ww÷(H2-H1)
Q = G ×r
= 1404×0.908
= 1275 (m3/h)
= 0.354 (m3/sec)
= 6.6 ÷ 0.0047
= 1404 (kg/h)
Drying Simulation 5Q.4 Calculate heat energy.
q = G×(e2-e1)
The kerosene that heat combustion is 10500kcal/kg, is used for fuel.
7523 (kcal/h) ÷10500 ( kcal/kg) = 0.72 (kg/h)
0.72 (kg/h) × 8 ( hours) = 5.76 (kg)
In this case, we need 5.76kg kerosene.
= 1404×5.1
= 7523 (kcal/h)
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
Initial moisture content
Dry air temperature
Drying rate
high low
low high
low high
Conclusion about quality
GrainGrain DryersDryers
Classification grain Classification grain dryersdryers
Batch type dryersBatch type dryers Continuous type dryersContinuous type dryers Storage type dryersStorage type dryers
Fixed temperatureRising temperature
Descending temperature
Ambient airDehumidification air
Heated air
No heated
air
Air flow rate per 1t
(m3/s・t)Drying 0.5-3
Bin drying 0.05-0.2Storage 0.02-0.002
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
Moisture contents meter
Electric Resistance type
Grain inlet (front)
Fuel tank
Control panel
Burner
Bucket elevator
Tempering section
Drying section
Suction blower
Feed inlet (side)
Upper screw
Feed roll
Sensor roll
Recirculating type dryer 1
Burner
Suction blower
Grain
Exhaust air
Heated air
Heated air
Exhaust air
Under screw Rotary valve
Recirculating type dryer 2
Recirculating type dryer 3
Heated air
Ambient air
Heated air dryer
Grain
Far -infrared radiation
Far -infrared radiation dryer
Burner
Radiation body
Burner
Ambient air
Heated air
Grain
Suction fun
Suction fun
Recirculating type dryer 4
Drying Chamber
Under Screw(U. S.)
FIR Body
Rotary Valve(R. V.)
Drying Chamber
Under Screw(U. S.)
FIR Body
Rotary Valve(R. V.)
DryingChamber
FIR body
Heated Air
Exhaust Air
FIR
Under Screw(U. S.)
Rotary Valve(R. V.)
DryingChamber
FIR body
Heated Air
Exhaust Air
FIR
Under Screw(U. S.)
Rotary Valve(R. V.)
Recirculating type dryer 5
Round type (for soy beam)
Large type (for facility)
(a) Columnar type (c) Inverted trough type(LSU)
(b) Buffle type
Flow of grain Flow of grain
Heated
air
Heated
air
Heated
air
Heated air tube
Exhaust air tube
Continuous flow type dryer 1
Exhaust air
Exhaust air
Drying chamber
Blower
Dumper
Air inlet
Burner
Grain inlet
Exhaust air
(a) Columnar type
(b) Buffle type
(c) Inverted trough type
Brower
Grain inlet
Drying chamber
Exhaust air duct
Air inlet
Leveler
Exh
aust
air
Rotary valve
Heated air tubeExhaust air tube
heat
ed a
ir d
uct
heated air
Continuous flow type dryer 2
Grain inlet
Burner
Suction Blower
The limit safe air flow rate in storage drying
Storage type dryer
Grain
Air flow Sweep floor
Direction of grain moving
Storage type dryer 1 Square bin type
Storage type dryer 2 Round bin type
Tank
Receipt
Blower
Lift
Container rack
Balance
Power supply
Control box
Storage type dryer 3
Rack type
Storage type dryer 4
Mixing husk type
Paddy tank
Husk silo Mixing silo
Husk separatorHusk dryer
(2-3%wb)
Husk tank
Raw paddy
Paddy tank
Husk siloHusk silo Mixing siloMixing silo
Husk separatorHusk separatorHusk dryer
Husk
Dried paddy To husk silo
(2-3%wb)
Storage silo Husk tank
From husk dryer
Raw paddy
Mixing ratio Raw paddy : Dried husk = 1 : 1.5 ~ 2
Storage type dryer 5Storage type using solar energy
Solar energy
Green houseReceiving section
Processing section
Rotary stirrer
Drying bed
Bin Bin
Measurement methodMeasurement method
Moisture contentMoisture content ①① Standard methodStandard method ②② Moisture meterMoisture meter
CrackCrack
Grain Coefficient
Paddy 1.0121
Weat 1.0086
Barley 1.0086
Beer 1.0071
Brawn rice 1.0122
Milled rice 1.0133
M105 = 100 - α ( 100-
M135 )
Moisture content 1
Moisture contents (% w.b.) =Before drying weight - After drying weight
Before drying weight
Drying conditions
M105 : 5g(ground grain) - 105 ℃ - 5 hours
M135 : 10g(whole grain) - 135 ℃ - 24 hours
-0.6
-0.4
-0.2
0
0.2
0.4
0.002 0.008 0.014 0.020 0.026
Absolute humidity (kg/kg‘)
Dev
iati
on
5g(ground grain)-105 -5hours℃
4g(whole grain)-135 -24hours℃
×100
①Measure 10g of grain and put into an aluminum can.
②Remove the cover downward and puts it into a
dryer (135 ).℃
③Take it out after 24 hours, puts it into a desiccator
with a desiccant, and be cooling for 30 to 40 minutes.
④Measure weight and calculate by the following formula.
Measure 3 times per 1 sample and describe
by average value.
Cock
Vaseline is applied.
Desiccant
<Procedure>Moisture content 3
.
Water contents meter 1
Electric resistance type
I
R
E
R E
I
I =E
R
R water contents∝
.
Water contents meter 2
Electric capacitance type
Q=CV
ε water contents∝
Ci
V
d
S
C=8.855×10-8εS
d
.
Water contents meter 3
Infrared moisture determination balance
Moisture contents are detected weight loss by heating and drying.
<Definition of crack grain>
(1) Grains that have 1lateral crack that goes all the way through.
(2) Grains that have 2 lateral cracks on one side that do not go all the way through; viewed from another surface there are 2 lateral cracks, which occur in difference parts of the grain.
(3) Grains that have 3 or more lateral crack on one side that do not go all the way through.
(4) Grains that have longitudinal cracks, regardless of them number or form.
(5) Grains in which there are honeycomb pattern cracks.
Crack 1
<Procedure>
①Cracking rate is measured by brown rice which husked by hand or handy husker.
②Good grain containing crack grain is measured.
③Measurement is judged in seeing through them with
the naked eye using equipment.
④Samples are extracted after drying. It is measured, after sealing this sample and
saving in normal temperature for 48 hours or more.
⑤The number of measurement grains are 250 grains.
Crack 2
100250
grains crack of Count(%) rate Cracking =
Rough rice WheatOther thanrough riceor wheat
Foreignmatter
g/l % % % % % % % % %
1st grade 810 701st gradesample
15.0 15 7 0.1 0.3 0.1 0.3 0.2
2nd grade 790 602nd
grade15.0 20 10 0.3 0.5 0.3 0.5 0.4
3rd grade 770 453rd
grade15.0 30 20 0.7 1.0 0.7 1.0 0.6
Offgradeupper
limit 770- - 15.0 100 100 5.0 5.0 5.0 5.0 1.0
Item/
Grade
Lower limits Upper limits
Damaged kernels, dead kernals, colored kernels, other grains and foreign matter
Moisturecontent
Testweight
Headrate
Graincharacter
Other grainsColoredkernels
TotalDead
kernels
HuskingHusking Separating Polishing
Engelberg rice huller polisher
One machine performs husking and polishing
Combination of husker,separator and polisher
This system simple but milling yield is lowPolisherSeparatorHusker
Space between rolls
Husking 1
Clamp
Brawn rice
Palea
Lemma×
Husking 2
Conclusion of Easy Husking
①Direction of Length
②Friction Force
(a) equal-diameter (b) difference-diameter
Husking 3
Roll type husker
nN d
D
n (rpm) > N (rpm) d (m) < D (m)
(a) equal-diameter (b) difference-diameter
Husking 4
Roll type husker
nN d
D
n (rpm) > N (rpm) d (m) < D (m)
Roll clearance ; 0.8 ~ 1.2
Ratio of peripheral velocity difference ; 0.23 ~ 0.24
Husking 5 Structure of roll type husker
300kg/h-1inc.
Liner
Impeller blade
Husking fan
Husking 6
Impeller type husker
Inlet paddy
Moisture contents (%)
Roll type husker
Impeller type husker
Hus
king
rate
(%)
Husking 7Relationship between moisture contents and husking rate.
Husking 8
Roll type Impeller type
Capacity (kg/h)
Husking rate (%)
Durability
Scared kernel
Air-gun eject type Flapper eject type
Good eject type
Bad eject type
Good eject type
Bad eject type
Flapper ejectorAir-gun ejector
ChuteBelt conveyer
Sensor
CCD cameraLight
Feeder
Light
CCD cameraLight
Back ground
Viewing chamber