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

Periodic table, what are the properties of d-block elements?

what are the properties of d-block elements?

Explain about parke process, Explain about Parke Process? Parke method ...

Explain about Parke Process? Parke method for refining lead, which is also a concentration process for silver, relies upon the selective dissolution of silver in molten zinc.

Phenol, Discuss the effect of substituents on the acidity of phenolic group...

Discuss the effect of substituents on the acidity of phenolic group?

Determination of acid insoluble ash of flour sample., I want to know how to...

I want to know how to determine the acid insoluble ash of a flour sample with principle,procedure as well as calculations.

Question, Write the alkali metals in increasing order acc to ther atomic ma...

Write the alkali metals in increasing order acc to ther atomic masses

Brief meaning of water of crystallization , In crystallography, water of cr...

In crystallography, water of crystallization or water of hydration or crystallization water is water that occurs in crystals. Water of crystallization is essential for the maintena

Illustrate relative amounts of two co-existing phases, Illustrate that...

Illustrate that  for  correct  mass  balance,  relative  amounts  of  two  co-existing  phases  or microconstituents must be given by lever principle. Ans:   Using  lever  rule

Determine the total ash content in flour, Q. Determine the total ash conten...

Q. Determine the total ash content in flour? After undertaking this activity, you will be able to: • assess the mineral content in the given sample of flour, • check th

Illustrate the structure of alkanes, Q. Illustrate the structure of Alkanes...

Q. Illustrate the structure of Alkanes? Ans. Alkanes have the general formula C n H 2n+2 . This means that for every n atoms of carbon, there are 2n + 2 atoms of hydrogen.

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