ENERGY MANAGEMENT IN THE WET PROCESSING OF GREIGE

FABRICS

Presenting author: Debashish Banerjee CEO – Blackstone Synergy

Consulting group Limited, P.O. Box – 23365, Nairobi -00604, Kenya

db@blackstonesynergy.com

1. Introduction:

The wet processing industry in the fabrics is a prominent user when it comes to guzzling

energy especially as temperatures are required to be maintained apart from the

generation of the fluid pressure to desired levels. The fabric serves as the substrate for

the dye uptake and hence the movement configuration has a significant bearing on the

dye affinity as also the structural orientation for facilitating the dye penetration.

2. Conceptual points:

The non-linear load is often ignored but is the main source of the generation of the

harmonic distortions in the fundamental sinusoidal AC current curve; the key

components of the high energy consumption.

The steam quality is determined by the consistency of the ignition point of the water that

is brought to the level of state change and the enthalpy rate achieved in the transfer

mechanism involved for the said state change. The detailed analysis of this mechanism

has often been ignored in the processing industry albeit this is certainly the key in

energy conservation measures.

The electrolyte movement is another friction builder and is a potential energy guzzler in

the dye transfer mechanism; hence this is an area and an intense subject for exploring

improvements in the energy conservation process.

3. Research mechanism adopted:

3.1. The primary area of research was to correlate the dye strength within a batch with

the varying changes in the steam pressure and the corresponding heat transferred into

the system as measured by the temperature gauge. The boiler pressure was regulated

at different levels to record the changes in the transferred temperatures to the beaker.

3.2. The dye strength was measured using the Kubenka-Munk equation K/S = (1-

R2)/2R wherein R is the fractional reflectance and the K = coefficient of color absorption

while S = coefficient of scattering of color.

3.3. Table 1: Comparative analysis of transferred heat V/S Dye strength

Color strength comparative analysis on transferred heat

Boiler

pressure

Transferred temperature

as measured by the gauge Fabric run speed

K/S (color strength

measure)

12 188 75 7.7

12.5 192 77 8.1

11.8 183 83 7.6

12.7 192 82 8.3

13.3 195 79 8.8

12.9 191 76 8.2

11.5 182 75 7.2

10.9 177 77 6.8

10.7 176 79 6.7

11.1 181 75 6.9

3.4.Inferences:

The relationships between the boiler pressure and the color strength characteristics as

determined by the X-rite color spectrophotometer were strong and hence merited

investigation from both energy conservation principles and the dyeing characteristics as

well.

The furnace oil boiler used in this trial recorded significant variations in the consumption

levels during the study period and the observed phenomenon had the following

reasons:

a) Fluid friction is known to increase with chemical degradation thereby raising the

operating temperatures and hence need to be contained to prevent precipitation of the

flash point lowering that might cause further irreversible damage to the properties of the

oil.

b) The variations in fluid friction cause drops in the steam pressure to be registered;

something that has far reaching implications for the dyeing quality and productivity

determined by the fabric run speed.

3.5. Solutions:

a) Car engine oil raised to a temperature of 80 to 85 degrees Celsius was used to dose

the furnace oil tank to the extent of 2% by volume and the experiment was repeated.

Following is the extract of the results:

Table 2: Solutions for the transferred heat V/S dye strength syndrome:

INFUSION OF CAR ENGINE OIL

@ 2%

Color strength comparative analysis on transferred heat

Boiler

pressure

Transferred temperature

as measured by the gauge

Fabric run

speed

K/S (color

strength

measure)

13.5 197 85 9.1

14 200 83 8.8

13.8 199 85 9.2

13.9 198 87 9.2

14.1 201 86 8.8

13.7 197 85 8.9

13.3 199 85 8.9

13.2 198 85 8.8

13.6 199 85 8.7

13.1 193 85 8.9

3.6.Inferences:

1) Productivity increase is observed through enhanced line speeds.

2.) The transferred heat is significantly higher

3) The important parameter of color strength is significantly improved.

The fuel consumption registered a gain of 8.21% with higher pressure and better fluid

friction dynamics owing to the flow properties of the oil.

3.7. Drive dynamics: Potential energy conservation measures:

The next area of focus in our study on the energy management initiatives was in the

area of drives. We registered the following readings:

PHASE

Water pump Intelli-drive - fundamental energy data

AMPERES VOLTAGE THD% KW KVAR KVA

R 26.79 425.2 2.18%

6.89 7.79 17.06 Y 11.94 426.2 12.21%

B 30.93 427.8 8.91%

PHASE

IMBALANCES 159% 1% 460%

Water pump - Intelli-drive - Power Quality Data

PF tan Phase

Angle Peak i RMS

CF

(Crest

Factor)

0.4 1.11 92

40.1 26.79 1.50

40.0 11.94 3.35

39.9 30.93 1.29

160%

3.8. Inferences:

1. Phase imbalances are quite high. These have serious implications on the cable

properties and the motor wiring.

2. The PF is low causing problems in the drive through the pump in response to the

intelligent responses of the software to the pump flow characteristics.

3. The tanis implying that the impedance factors have set in causing a redundant

electromagnetic field; in effect, this reduces the flux strength considerably and is serious

deterrent for the energy conservation measures in the drives for the processing

industry.

3.9 Thermostat regulated drive quality

PHASE

Thermostat regulated AC drive for the dye pump -

fundamental energy data

AMPERES VOLTAGE THD% KW KVAR KVA

R 19.43 416 16.47%

3.68 2.42 11.64 Y 13.67 417.1 14.90%

B 14.76 417 24.52%

PHASE

IMBALANCES 42% 0% 43%

3.10. Inferences:

1. The phase imbalances are significant implying issues for the dye pump.

2. The THD% or the total harmonic distortion percentage is quite high and hence

implies high thermal stresses and fundamental increase in the energy quantum.

3. The low kW load is indicating the pump characteristics are weak and would require

changes in the head configuration for improved performances.

Thermostat regulated AC drive for the dye pump - Power

Quality Data

PF tan Phase

Angle Peak i RMS

CF

(Crest

Factor)

0.32 0.65 66

28.0 19.43 1.44

27.9 13.67 2.04

27.9 14.76 1.89

42%

3.11. Inferences:

1. High CF or crest factor implies huge thermal stresses in the line causing elevated

ambient heat and low dissipation.

2. The power factor is low causing issues in the pump flow characteristics for the dye.

3.12. Energy audit findings:

Major findings of the energy audit carried out as part of the research project:

1. The energy density in terms of both the cost per unit as well as the fabric processed

in meters per m3 of water consumed is extremely inefficient.

2. The conservation of thermal and electrical energies as envisaged in the detailed

energy logger studies clarify the extent of improvements that can be brought about by

the rigors of implementation.

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Water density in meters / m3

Water density in meters / m3

Poly. (Water density in meters / m3)

3. The harmonic distortion in the odd harmonics; especially the 1st, 3rd and 5th

harmonics constitute the bulk of the negative vector characteristics and hence influence

the cable and wiring characteristics significantly.

3.20. Recommendations for solutions in the electrical energy containment in the wet

processing industry

PROCESS HOUSE ENERGY SAVINGS RECOMMENDATIONS

OBSERVA

TIONS

ROOT

CAUS

E

ANAL

YSIS

RECOMMEN

DATIONS

ESTIMA

TED

INVEST

MENT

K

W

H

US

$

PAYB

ACK

PERI

OD IN

MONT

HS

ANN

UAL

ROI

IMPLEMEN

TATION

PLANS

THE

PROCESS

HOUSE

NEEDS TO

RE-WIRE

COMPLET

ELY

The

phase

angles

are

high

and PF

is low

indicati

ng wear

of the

wires

Usage of

85mm2 for both

input and output

is recommended

for the electrical

safety

55000 720

00

129

60 51 24%

December,

2016

PF

CAPACITO

R BANK

AND NEW

BUS BAR

COMPATI

BLE WITH

300 KVAR

The

new

capacit

or bank

shall

make

the

system

energy

efficien

t

PFC capacitor

banks ( Class

5860)

REFERENCE :

PAGE 5 OF

THE

SCHNEIDER

BROCHURE

ENCLOSED

HEREIN

250,000 720

00

129

60 231 5%

December,

2016

3.21. The major implications of the recommendations:

a) Cables and wires for the induction motors in the process lines need to be oversized

fundamentally to the tune of 35-50% to accommodate for non-linear load applications in

the form of intelligent drive systems that run on process-specific software.

b) The abrupt changes in the peak current profile in non-linear load profile is typical of

AC drives and hence need corrections at the Power factor bank level through an

extensive use of rectifiers that compensate for the high harmonic distortion percentage

and save on the cables to contain the high crest factor – the multiplier for the peak and

baseline currents.

c) The copper purity gets dented at high thermal stresses owing to local heat and lead

to micro-rupture along the wiring that eventually leads to high leakage of current.

The company – Blackstone Synergy Consulting Limited intends to reach out to a high

cross-section of wet processing units and is willing to tie-up with the OEMS for

processing lines to compensate for the inherent anomalies and potential energy

guzzling points and improve on the quality of wet processing significantly.

The dye affinity for the fabrics and the overall energy profile can improve by a

conservative estimate of 45-55% in terms of the energy density as explained in the

article with facts and figures.

Source for all the trials mentioned in the paper are three different mills wherein the trials

were conducted; two in India and one in Indonesia.