Sunday, February 12, 2012

ENERGY CONSERVATION IN WET PROCESSING


(a)    ENERGY CONSERVATION IN SIZING
Foam sizing : in this method foam is used for sizing. Hence considerably less water is required as compared to the conventional sizing. This results is saving in energy and time for evaporation of size.

High pressure squeezing during sizing : this saves the energy as well as the water. after sizing material is squeezed at high pressure to remove maximum water from it. Because of this energy required for drying the material is saved.

Simultaneous dyeing and sizing: for denim warp yarns by using rapiodogen dyes and stabilizer with sizing formulation sizing and dyeing can be carried out simultaneously. This saves energy and water.

B) ENERGY CONSERVATION IN BLEACHING
Fast bleaching with VAPORLOC machine
Mather and platt developed this machine. In this machine, bleaching can be carried out in 90 to 120 seconds at a temperature of 135 degree C. and pressure 30-psi. for this process hydrogen peroxide, stabilizers and suitable alkali is used. 50% energy can be saved with this process.

Novel method : this is a combined desizing scouring and bleaching of polyster/cotton blend. This is carried out is which using material to liquors ratio1:25. the liquor consists of hydrogen peroxide(35%w/v) magnesium sulphate heptahydrate (1.6gpl) sodium hydroxide(4gpl) wetting agent (0.5gpl) EDTA(2gpl) and gluconic acide (2gpl) at 95 degree C for one hour. The washing is giving at 95 degree C.

Potassium permanganate method : cotton goods can be bleached with potassium permanganate. This saves energy and water. It also gives eco-friendly effluent.

Cold pad-batch method : in this method peroxide bisulfate used as a bleaching agent. The bath also contains some compounds which accelerate the bleaching reaction like urea glucose sodium citrate methyl carbonate tetra acetyl ethylene diamine etc.

DSB process: in this process desizing scouring and bleaching takes place in a single stage. The bath contains hydrogen peroxide peroxygen booster sodium silicate peroxide sulphates etc. to this some compounds like urea glucose which accelerate the peroxide reaction are added. This process saves energy water and labor.

C) ENERGY CONSERVATION IN MERCERISATION
It is the process in which the material is treated with concentrated sodium hydroxide solution indeally at at 15 to 20 degree C. this gives luster to the material and the absorptivity of the material is increased considerably.
In mercerization process saving in energy can be done if the process is carried out on wet-on-wet basis I e the in between drying process is eliminated which saves the energy.
Hot mercerization can be done so that scouring is eliminated at 70*c so without doing separate scouring process yarn or fabric is directly subjected to hot mercerization.
Caustic recovery : for the caustic recovery maximum washing is given to the fabric. Temperature of the washing water is maintained at 90*c and suction is provided. All this results in 80 to 85%  of the caustic recovery.

D) ENERGY CONSERVATION IN DYEING
Cost savings and quality improvement in dye house can be dine by some process modifications and suitable replacement of processing machines.
Some of these processes are given bellow.

Energy saving by padding mangle
Cost savings and quality improvement in dye house can be done by some process modifications and suitable replacement of processing machines.
Some of these processes are given bellow.

Energy saving by padding mangle
Padding mangle mainly used for two purposes 1) to impregnate any processing solution in fabric 2) to remove excess amount of processing liquor from the fabric by squeezing. Kusters mangle is a modified from which has uniform expression percentage with low wet pick-up. Expression percentage can be changed by changing speed and pressure. On this machine uniform and accurate results are obtained with the saving in energy.

Pad-jig method
This method can be used for dyeing with vat reactive azoic dyes with this method. Dyeing quality is improved with respect to levelness and solidity of shades. Dye penetration is also good. In this power & steam required is less.


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