Dissolved oxygen in water, Chemistry

Assignment Help:

Q. What do you understand by dissolved oxygen in water? How does it create trouble in boiler? Give chemical methods with suitable reactions to remove it from the water.

Ans.

Presence of dissolved oxygen: At room temperature about 8 ppm of dissolved oxygen is present in water. Oxygen enters the boiler through raw make up water. When water containing the free gas is evolved under prevailing high temperature of boiler and attacks the boiler material.

2Fe + 2H2O + O2 = 2Fe (OH) 2

4Fe (OH) 2 + O2 + 2H2O = 2[Fe2O3.2H2O]

Removal of dissolved oxygen:

1. Chemical means: Oxygen can be removed by adding calculated amounts of certain chemicals such as Na2SO3, Na2S and N2H4.

         Na2SO3 + O2 = 2Na2SO4

      Na2S + 2O2 = Na2SO4

However, the sodium sulphate so formed may decompose in high pressure to form H2SO4. Hydrazine (N2H4) is found to be an ideal compound for removing dissolved oxygen since the products are water and nitrogen gas

                                          N2H4 + O2 = N2 + 2H2o

Mechanical means: It works on Henry's law and Dalton's law. Solubility of gas is directly proportional to pressure. Mechanical desecrator is used 


Related Discussions:- Dissolved oxygen in water

Methods of characterization, Introduction Methods of characterization a...

Introduction Methods of characterization aim to calculate the products of a reaction. The level of detail expected depends on the circumstances, and calculates the range of met

Equilibrium calculations, One mole of gas A decomposed exothermically into ...

One mole of gas A decomposed exothermically into one mole of gas B and one mole of gas C with Kp = 1.8 x 10-5 at 300 K. If the initial pressure of each gas was 0.150 atm, what were

Which set of quantum numbers are not possible, Which set of quantum numbers...

Which set of quantum numbers are not possible from the following: (1) n=3, l= 2, m=0, s= -1/2                 (2) n=3, l= 2, m=-2 s= -1/2            (3) n=3, l= 3, m=-3,

Organic compounds, may i know the number of organic compounds

may i know the number of organic compounds

Crystals, what is a crystal and why do crystals have regular faces?

what is a crystal and why do crystals have regular faces?

Cycloalkanes, Why cyclo propane is more stable than cyclohexane

Why cyclo propane is more stable than cyclohexane

Explain sources of antioxidants, Sources of antioxidants The primary bi...

Sources of antioxidants The primary biological role of antioxidant is in preventing the damage that reactive free radical can cause to cells and cellular compounds. In fact, al

Research theories, What is the difference between a theory and a hypothesis...

What is the difference between a theory and a hypothesis? What is the difference between a hypothesis and a law? Is there a sequential move from one to another, amongst law, theory

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