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Delignification in Wood

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Questions and Answers

What is the primary cause of delignification in the wood?

Fungal attack

Excessive water flow

Oxidizing agents and alkaline materials (correct)

Mechanical wear and tear

What is the effect of delignification on the appearance of the wood?

The wood becomes smoother and more uniform

The wood looks white or bleached and the surface becomes rougher (correct)

The wood becomes discolored and darker

The wood remains unchanged in appearance

Which of the following is a key condition that leads to severe deterioration of the wood due to delignification?

High pH and high chlorine residual (correct)

High pH and low chlorine residual

Low pH and low chlorine residual

Low pH and high chlorine residual

Which type of corrosion is characterized by cracking of metal under tensile stress in a corrosive environment?

Stress corrosion cracking Signup and view all the answers

How do microorganisms contribute to corrosion in the cooling system?

They form biofilms that trap water and concentrate corrosive products. Signup and view all the answers

What is the primary difference between crevice corrosion and pitting corrosion?

Crevice corrosion occurs in shielded areas, while pitting corrosion occurs in open areas. Signup and view all the answers

What type of cooling water system is characterized by the water being recirculated in a closed loop?

Open recirculating system Signup and view all the answers

Which oxidizing agent is commonly added to cooling water systems to control microbiological activity?

Sodium hypochlorite Signup and view all the answers

In an open recirculating system, what is used to cool the water and reduce the need for water makeup?

Recycling the water through the plant Signup and view all the answers

Why is chemical treatment economical in closed recirculating systems?

Minimal loss of chemicals Signup and view all the answers

What is a common use of closed recirculating systems?

Cooling gas or diesel engines Signup and view all the answers

How does an open recirculating system handle the remaining water that becomes concentrated with minerals?

By controlling concentration with blowdown Signup and view all the answers