Abstract:
Caustic soda also known as sodium hydroxide is a chemical widely used by multiple
industries all over the world. One such industry is the textile industry which utilizes
caustic soda in the wet processing of fabric to improve the luster and quality of the
fibers. The effluent from these processing sections contains wastewater with a high
amount of sodium hydroxide, which remains unreacted. This project focuses on the
recovery of caustic soda from these wastewater streams to reduce the costs spent by
the industry in buying the raw material.
The main objective of this project is to concentrate a dilute five percent lye solution
up to forty percent, which can then be reused as raw material for the processing
sections. Different concentration enhancing techniques have been described in detail
and the importance of using the evaporation method is highlighted. A triple effect
evaporator system is designed manually and simulated on Aspen HYSYS to compare
the results.
The user for triple effect evaporator what is the concentration of caustic solution
provides a high steam economy of two point three kilograms of water evaporated per
kilogram of steam with a low capital investment and payout period of 2.3 years. Three
thousand five hundred kilograms per hour of water is obtained from a four thousand
kilograms per hour Caustic feed solution.
The Caustic Recovery Unit serves a dual purpose of enhancing the concentration as
well as the generation of hot water minimizing energy losses.
