Question

Which one of the following is the main combustible component in biogas?

• A. Methane
• B. Carbon Monoxide
• C. Hydrogen
• D. Oxygen

Hint:

Combustible part of Biogas = Methane ($\text{CH}_4$). Combustible part of Producer Gas = Carbon Monoxide ($\text{CO}$) + Hydrogen ($\text{H}_2$).

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Biogas is generated through the anaerobic digestion of organic matter by methanogenic bacteria, producing a combustible mixture of gases.
Key Formula or Approach:
\[ \text{Organic matter} \xrightarrow{\text{Anaerobic bacteria}} \text{CH}_4 (55\text{--}70\%) + \text{CO}_2 (30\text{--}45\%) + \text{Trace gases} \]

Step 2: Detailed Explanation:
Typical composition of biogas:
- Methane (\(\text{CH}_4\)): \(55\text{--}70\%\) (The primary combustible hydrocarbon fuel component with calorific value \(\approx 20\text{--}25\text{ MJ/m}^3\)).
- Carbon Dioxide (\(\text{CO}_2\)): \(30\text{--}45\%\) (Non-combustible).
- Traces: \(\text{H}_2\text{S}\), \(\text{N}_2\), \(\text{H}_2\), moisture (\(< 2\%\)).
Methane is the dominant combustible component that provides the heating value of biogas.

Step 3: Final Answer:
Thus, the main combustible component in biogas is Methane, matching option (A).