Aramids for low weight and low rolling resistance of conveyor belts

Aramids for low weight and low rolling resistance of conveyor belts

Aramids for low weight and
low rolling resistance
of conveyor belts
Gerard van den Hondel
Teijin Aramid B.V.
BulkSolids Europe 2010
Glasgow, 9 September 2010
Aramids for conveyor belts
1. Belt weight
-
Aramid compared with
traditional reinforcement
Lower weight
Energy saving
2. Indentation rolling resistance
-
Sulfron in rubber and tan δ
Lower rolling resistance
Energy saving
Examples/case histories
What is Aramid & what are its properties?
Aromatic Polyamide
-
Strength of steel
-
1/5th of weight of steel
-
High modulus
-
Chemical resistant
-
Temperature resistant
polyparaphenylene terephthalamide
1. Tensile properties of Aramids for belts
Tenacity / Elongation at 20°C
Twaron Aramid yarn:
2500
Twaron
High tenacity =
Tenacity (m N/tex)
2000
tensile strength
1500
on weight basis
1000
3 x Polyester
PET
Steel
500
PA 66
5 x Steel wire
0
0
5
10
Elongation (%)
15
20
High modulus
Shape of Aramid belt reinforcement
Cord fabric
- Cords from twisted Aramid yarn
- In length direction (warp)
- Optimal belt tensile strength
Straight warp fabric
- Cords from twisted Aramid yarn
- In length direction (warp)
- Optimal belt tensile strength
- Transverse strength from (PA)
yarn (weft)
Maritsa Istok-2 power plant 2,6 km belt
Pipe conveyor belt design
-
Closed = no ash spil
low power consumption
Distance
2,6 km
Width
1,4 m
Strength
1.600 N/mm
Steel
44 kg/m
Twaron Aramid 29 kg/m
Payload
118 kg/m
Maritsa Istok Aramid pipe conveyor
Belt total moving weight = belt + load
118 + 44 =
162 kg/m
- Aramid 118 + 29 =
147 kg/m
- Steel
9% lower weight power saved
Case history data
- Belt runs since 2000
- 2009: additional belt installed
5,8 km distance, class 2.500 N/mm
100
80
60
40
20
0
1st 4th
Qtr Qtr
Ea
st
We
st
No
rth
Elongation / take-up length in %
Aramid conveyor belts in Tunisian mine
4,5
4
3,5
Elongation min.
3
Elongation max.
2,5
Conveyor take-up
2
1,5
1
0,5
0
Polyamid 6.6
Polyester
Aramid RE
Aramid LE
Steelcord
HE
Steelcord
Belt Types
Tunisian Phosphate Mine
-
Transport Distances 3 + 4 km
Originally steel short take up length
Aramid for corrosion resistance: also short take up length
10 years of succesful operation
2010: belt rubber worn, new Aramid belt installed
Summary 1: Aramid low weight reinforcement
Twaron Aramid can replace steel
Long term operational examples:
- Bulgaria power plant
- Tunisia phosphate mine
Aramid is as strong as steel
at only 1/5th of weight of steel
Weight saving of (loaded) belt
approximately 10%
Comparable power saving
2. Indentation rolling resistance
Pulley Cover Indentation = 61%
18%
For long horizontal belts:
> half of drive energy lost
1%
in indentation rolling resistance
9%
5%
61%
6%
Indentation rolling resistance
Bearing resistance of the idler
Flexure resistance of the belt
Flexure resistance of bulk material
Secondary resistances
Extraordinary resistances
Loss in rubber
rolling over the supports
due to hysteresis
The belt rubber hysteresis cycle
Grey area W
Energy loss per hysteresis cycle =
Rubber indents on each roller
Long haul belts
Thousands of rollers
Accumulated energy loss 61%
Remedy
Energy optimized
rubber compounds
Introducing Aramid based Sulfron
Base: short cut aramid yarn
Pellet shaped, app. 6 mm
Mixed in rubber compounds
@ ~ 2 phr
Reduction of tan δ with Sulfron
0,220
Tan δ loss factor
CMP1 (Control)
CMP2 (1,5 Phr S3001)
CMP3 (2,0 Phr S3001)
CMP4 (3,0 Phr S3001)
0,200
Sulfron reduces interaction
0,180
0,160
In NR/SBR with Carbon Black
Tan δ is 20 – 30% lower
Expected power saving: 15%
loss factor (tan δ )
between reinforcement particles
0,140
0,120
0,100
0,080
0,060
0,040
Dynamic strain: 2 %
Frequency: 10 Hz
0,020
(25% of 61% indentation
rolling resistance)
0,000
0
10
20
30
40
50
60
70
o
Tempearture ( C)
80
90
100
110
Summary 2: Sulfron reduced rolling resistance
Sulfron pellets are Aramid based
Mix @ ~ 2 phr in rubber compound
NR/SBR Carbon Black compounds
Tan δ is 20 – 30% lower
15% of belt power reduction
expected
Tests in progress
Aramid yarn and Sulfron in belts
1. Reduced belt weigth
Low weight aramid reinforcement
Energy saving
2. Reduced rolling resistance
Indentation rolling resistance
lowered with Sulfron in rubber
for lower tan δ
Energy saving
Was this all a fairy tale?
I hope part of it was ….
You recognized Rumpelstiltskin?
The tale where yellow strands …
Were spun into pure gold …
What will aramids save on the energy bill
of your next long haul belt?