What is the main constituent of biogas? How is biogas obtained from biomass? Write any two advantages of using this gas. (Delhi 2011)

Solution

The main constituent of biogas is methane. Other than methane, the gases present are hydrogen, carbon dioxide and hydrogen sulphide.

Biogas is obtained from the excretion of animals like cow dung and plant wastes.

Following is the composition of biogas:

Methane: 50% to 75%

Carbon dioxide: 25% to50%

Nitrogen: less than 10%

Hydrogen: less than 1%

Hydrogen disulphide: less than 3%

 

Benefits of Biogas:

• Biogas, or methane, is a clean-burning, "green" fuel used for heating and other purposes.
• Biogas is more economical.
• The cattle dung is converted into inflammable gas and good quality manure.
• Biogas provides a high efficiency fuel.
• The manure obtained from biogas plant has higher nutritive value as compared to that of ordinary farmyard manure.
• Biogas plants keep the household and surroundings clean.
• Biogas controls environmental pollution by eliminating the smoke from cow dung, which is harmful to eyes and lungs and promote public health.