Caustic embrittlement, Chemistry

Assignment Help:

Caustic Embrittlement: Caustic embrittlement is a type of boiler corrosion caused by using highly alkaline water in the boiler. During softening process by lime-soda processes, free Na2CO3 is usually present in small proportion in the softening of water. In high pressure boilers, Na2CO3 decomposes to give sodium hydroxide and carbon-dioxide.

  Na2CO3 + H2O = 2NaOH + CO2

And this makes boiler water "Caustic". The NaOH containing water flows into the minute hair cracks, always present in the inner side of boiler, by capillary action. Here water evaporated and the dissolved caustic soda concentration increases progressively. This caustic soda attacks the surrounding area, thereby dissolving iron of boiler as sodium ferrate. This causes embrittlement of boiler parts, causing even failure of the boiler. Caustic cracking can be explained by considering the following concentration cell. The iron surrounded by the dilute NaOH becomes the cathodes sides, which the iron in contact with concentrated NaOH becomes anodic part, which is consequently dissolved or corroded.

 

 


Related Discussions:- Caustic embrittlement

What do you understand by replication by dna, (a) Write chemical equations ...

(a) Write chemical equations for the reactions of glucose with (i) Acetic anhydride and (ii) ammoniacal silver nitrate solution. (b) Draw simple Fischer projections of D-g

Effect of various additives on the stability of egg foam, Q. Effect of vari...

Q. Effect of various additives on the stability of egg foam? recognize the different stages in the foam formation, explain the effect of various factors in foam format

Emulsions and Surfactants, What can you do to make Triethanolamine stearate...

What can you do to make Triethanolamine stearate less soluble in lipids?

What are the cationic and neutral ligands, Q. What are the Cationic and neu...

Q. What are the Cationic and neutral ligands? The names of all anionic ligands end in '0' replacing the final 'e' in endings. Sometimes endings are also changed. Thus the given

Molar conductivity, what is molar conductivity at infinite dilution

what is molar conductivity at infinite dilution

Describtion of carnot cycle, The Carnot cycle consists of four processes in...

The Carnot cycle consists of four processes in succession: 1. isothermal compression from T L , V 1 to T L , V 2 2. adiabatic compression from T L , V 2 to T H , V 3 3

Net Ionic Equation, When Solutions of ammonia and Iron (II) bromide are mix...

When Solutions of ammonia and Iron (II) bromide are mixed, what is the net ionic equation?

Explain the effects of temperature on multicomponent systems, Explain the E...

Explain the Effects of Temperature on multicomponent systems? For some of the derivations in this chapter, we will need an expression for the rate at which the ratio μ i /T var

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd