RAFAE Engineering
Caustic Recovery Systems
For Mercerizing Lye
Contact:0300-4472021
In textile finishing during Mercerizing textile goods are treated with caustic soda with 26-30 deg Be concentration in mercerizing compartment. In the following stabilizing department the quickest possible neutralization takes place and maximum caustic is washed out in this compartment.
A finishing mill, which mercerizes average 20000Kg fabric/day, will be consuming almost 10000kg caustic soda/day with 50% concentration.
RAFAE Engineering being pioneer in Caustic Recovery System offers first time in Pakistan using its innovative technology, which operates with extremely high thermal efficiency.
Following example can explain the advantages of recovering caustic from the drain of mercerizing:
5000Kg/h
Alkaline wastewater
6-8 Be
Theoretical saving can be calculated as follows:
5000kg/h x 5%=250kg/h NaOH 100%
=500kg/h NaOH 48 Be
If the price of NaOH is Rs. 12/..per kg, the wastage would be
500kg/h x 12 Rs/h=6000 Rs/h.
If you mercerize 6864 h/year (22h/day, 26 day/month) the loss would be approximately Rs.41,184.000/..per year.
This worth amount you can save in caustic soda alone. Other advantages of cost saving in wastewater treatment, hot water generation for washing are additional.
RAFAE’s caustic recovery plant reconcentrates caustic soda by evaporating water economically using vacuum technology. Caustic soda is recycled back to mercerizing and evaporated condensed water can be used for washing purposes in preferably mercerizing and bleaching. RAFAE’s caustic recovery system requires steam and cooling water for its operation, however it is always economical to recover caustic soda from wastewater.
Water
4700 Lit./h
Caustic Soda 1240kg/h 28Be
1000Kg/h Fabric
1000kg/h Fabric
Stabilizing
~1178 kg/h Reconcentrated NaOH 28 Be
RAFAE Engineering
Caustic Recovery System
3822Kg/h
Evaporated condensed water, usable at mercerizing, bleaching etc.
Advantages:
- Can save millions of rupees by recycling caustic soda
- Can reduce size and space required for wastewater treatment plant thus drastically reducing capital cost of wastewater treatment plant.
- Can reduce the running cost of wastewater treatment plant. High cost involved in neutralizing large quantity of caustic soda is saved. (1g NaOH requires 1.225g H2SO4 for neutralization)
- Can reduce management cost of solid waste disposal.
- Hot water is generated as by product from its waste heat, which is used in other process needs.
Working principle of RAFAE’s Caustic Recovery System:
The steam condensate of the first stage is returned to steam boiler feed water tank. The mixture of alkali and vapors is collected in specially designed separators, which circulate lye to the bottom of heat exchanger and hot vapors to next stage as heating media. A pressure gradient is maintained between 1st and last stage with the help of vacuum pump, which is necessary for economical evaporation. The vapors in the last stage are condensed in the water-cooled condenser. This high temperature distilled water is reused in mercerizing wash boxes.
Data required to design your system
Following basic information would be required to design caustic recovery system for your mercerizing machine. Any information missing will be assumed to the best of our experience in this field.
Fabric mercerized M/month (average)= ____________
Average GSM = ____________
Average width M = ____________
Production hours/day,/month = ____________
Flow rate of weak lye Kg/h = ____________
Type of mercerizing process = ____________
(Bleached, desized)
Mercerizing Machine type = ____________
Average speed of machine = ____________
Concentration of weak lye = ____________
Steam pressure = ____________
Cooling water temperature = ____________
For saving/pay back calculation
Cost of 1 ton steam = ____________
Cost of NaOH 100% concentration/kg = ____________
Cost of H2SO4 /kg = ____________
Cost of electricity/KWh = ____________
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