Caustic Recovery Plant (CRP)

Mercerization is a process in the textile industry where the textile fibres under tensile stress are treated with caustic soda. These cotton fibres swell in the caustic solution thereby giving it a better luster, improved dyeability, dimensional stability and marginal increase in tensile strength.

Once the fabric is mercerized, the weak caustic liquor can be drained into the effluent treatment plant, which would create havoc in the ETP due to its highly alkaline nature. Due to high pH values, it will require lots of acid to neutralize, there by increasing the TDS of the effluent. A good Caustic Recovery Plant can turn a very large proportion of this weak lye into reusable concentrated caustic soda (strong lye). With proper filtration and purification processes in place, this recovered caustic soda of desired concentration can directly be used for mercerization again.

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  • Features
  • Applications
  • Specifications
  • The weak lye is concentrated into strong lye by water evaporation
  • The CRP is based on the falling film evaporation method
  • The steam is passed inside the shell on the outside of the tubes and lye inside the tubes is heated and starts boiling
  • The lye boils in the heating tubes, the mixture of lye and vapour flows into the Vapour Separator, where the vapour is separated from the circulating lye
  • The same vapour is used as a heating medium in the next stage
  • Partial vapour is used to preheat the weak lye.
  • Weak lye can be concentrated into strong lye and re-used in the process, thereby sustainability in the mercerization process.
  • Recovery of excellent quality water from the vapour condensate which can be re-used.
  • Recovery of heat from hot water, there by better energy efficiency.
  • Lesser challenges at the ETP due to high pH drain being arrested.
  • Return on investment less than one year.
  • Type : Shell & tube type heat exchanger
  • MOC : MS, SS304, SS316, SS316Ti & Duplex
  • Heating Media : Steam, Thermic Oil
  • Capacity : 5KLD to 600KLD