Objective 07: Hydrogen Zeolite Softening

Question 1

What is a shortcoming of Sodium Zeolite Softening?

Answer 1

It does not reduce the total amount of salts dissolved in the water. One of the sodium salts it eventually produces, sodium bicarbonate will decompose in the boiler, forming sodium carbonate, sodium hydroxide, and carbon dioxide.

Question 2

What is an advantage of Hydrogen Zeolite Softening?

Answer 2

It removes scale forming salts without forming sodium bicarbonate.

Question 3

What does Hydrogen Zeolite Softening do?

Answer 3

It removes calcium, magnesium, and sodium cations from the salts in the water and replaces them with hydrogen ions. The mineral salts are converted into acids which are then neutralized using an alkali or base or by mixing the effluent with effluent water from sodium zeolite softener.

Question 4

What can the Hydrogen Zeolite be made of?

Answer 4

1. Lignite
2. Sulphonated Coal
3. Coke
4. Synthetic Resin

Question 5

How is the Zeolite regenerated in Hydrogen Zeolite Softening?

Answer 5

Sulphuric acid is passed through the zeolite where it exchanges its hydrogen ions (H) for the Ca, Mg, and Na ions in the zeolite. The reactions produce sulphates which are then rinsed to sewer.

Question 6

What is the purpose of the degassifier?

Answer 6

To remove carbon dioxide which can form carbonic acid

Question 7

How does the degassifier work?

Answer 7

Water from the zeolite exchangers flows downwards over trays, where it is scrubbed by upward flowing air, from a blower. The air carries the released CO₂ to atmosphere, while the water collects in the bottom and is removed by a transfer pump to storage.