hot mix plant
TRANSCRIPT
Hot Mix Asphalt Production
• Plant types and basic components• Plant calibration• Dust extraction• Filler handling and control• Aggregate heating• Procurement / handling of raw materials• Finished product storage• Delivery
Drum Mix Plant - Conventional
HMA made continuouslyand sent to storage silos
Drying and mixing drum
Bitumen Tanks
Scalping screen to remove oversize aggregate
Cold Feed Bins
Belt scale
Primary dust
collector
Filter Baghouse
Hot Storage Bins
Exhaust Fan
TWIN DRUM PLANT : COUNTER-FLOW
Old Drum Mix Mix Plant:
Twin Drum Plant
RAP Feed
Aggregate feed
Drying & heating Drum
Coating & mixing drum
Finished product storage
Plant filler storage and feed
Filter Baghouse
Parallel-Flow Drum-mixer Zones
CombustionHeating DryingAir
BIT.Hot MixAsphalt
Mixing
Counter-Flow Drum-mixer Zones
Aggregate
Air
BitumenHot MixAsphalt
Combustion Heating DryingMixing
Counter-Flow Batch Plant Dryer Zones
Hot Aggregate
Combustion Heating Drying
Aggregate
Air
Batch Plant Elements
Cold feed bins
Drye
r Dru
m
Bitumenstoragetanks
Hot Storagesilos
PrimarycollectorFilter Baghouse
Batch/Mixing tower
RAP Feed
Hot aggregate travels up bucket elevator
Pugmill
Aggregateweigh hopper Bitumen
weighpot
Hot mixasphaltdispensedinto truck / hot-bin
Aggregatefrom dryer
Aggregate to screens
Screens sizeaggregate
Bitumen Weigh-hopper
Aggregate and bitumen weigh hoppers
Aggregate Hot Bins
Warren Brothers Patent Application Drawing: Original
Batch Plant
Belt Scale Calibration
Cold feed system
Belt scaleReference
scale
Cold Feed Bins and RAP Bin
“Graphing the Feeders”
Feeder #1
01020304050607080
20 50 90
Belt Speed or Potentiometer Setting
To
ns
pe
r H
ou
r
Tachometer Mounted on Tail Pulley of Cold Feed Bin Belt
“No Flow” Paddle at Feeder Discharge
Induced Air Burner
Fuel Reticulation and Heating System
In-line heater HFO Sampling pt
HFO Tank
Temperature Profile of Counter-Flow Dryer
150º C 100º C20º C
Gases
Aggregates
Combustion HeatingDrying
150º C300º F
760º C 120º C
400º C
800º C
0º C Aggregate
Drum Flights / Lifters
Primary and Secondary Emission Control
Drying Drum
Primary Dust Collector Secondary
Dust Collector
Exhaust Fan
Filtered Air
Fines collected and returned
Primary Collector:Cyclone
Multi-Tube Collector
Outlettube
Spin vanes
Inlettube
Valve
Collectorelement
Gas inlet
Discharge Housing Functions as a Knockout Box
Gas flow
Air
Optional knockdown plate
Bitumen
Fines mixwith hot mix
asphalt
Cutaway Section of a Typical Baghouse
Pulse Jet Baghouse
Dust screw Dust screw
Exhaust fanExhaust fan
Manifold
Manifold
Automatic Damper Controls
Cyclone, Screw Collector, and Hot Elevator
Batchtower
Hot Elevator
Cyclone feeding fines directly back
Filler Weigh-Pod After Surge Silo
Emission Control Summary
• Remove particulate matter– Primary– Secondary
• Return fines to the mix– Affects void content– Affects mix stiffness– Difficult to control
Batch plant filtration
Aggregate storage
Aggregate Storage
BITUMEN TANKS – ELECTRICALLY HEATED/
24 HR TEMPERATURE MONITOR AND CONTROL
Bitumen Storage
Old Style Operating Cabin
Plant automation: Modern control cabin:
Plant automation
Roodepoort Op ScreenPlant Automation – Operating System Graphics
Batch Plant Schematic
Batch Plant Op Screen
Laboratory from the past
Modern Asphalt Laboratory
Quality Control Trends Monitored
Binder Content
-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
Sample No.
V.I.M.
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
Sample No.
Filler Content
-1.5
-1
-0.5
0
0.5
1
1.5
Sample No.
Binder Content
Voids in Mix
Filler Content
Slat Conveyor Feeding Storage Silos
Hot Storage – Skip and Winch System
Plant Mixing Tower
Skip Bucke
t
Winch
Storage Silo: 165 t Capacity
Correct Loading Sequence
The good old days
The End