Coal gas is primarily made from coal through a process called gasification.
What is Coal Gasification?
Based on the provided reference, gasification is a process in which coal is partially oxidated by air, oxygen, steam or carbon dioxide under controlled conditions to produce a fuel gas. This means that instead of burning the coal completely, it reacts with limited amounts of oxygen or other agents at high temperatures. This reaction converts the solid coal into a mixture of gases, which constitutes the coal gas (or synthetic gas/syngas).
Key Agents Used in Gasification
The reference highlights several agents that can be used to react with the coal during gasification:
- Air
- Oxygen
- Steam
- Carbon Dioxide
The choice of agent influences the composition and heating value of the resulting gas. The process is carefully controlled to ensure the correct partial oxidation reaction occurs.
Post-Gasification Steps
The reference also notes that after the gasification reaction, the produced fuel gas is very hot. Therefore, further steps are necessary:
- Cooling: The hot fuel gas is cooled in heat exchangers. This cooling process can often be used to generate steam, capturing some of the thermal energy.
- Cleaning: Before the gas can be used (e.g., for combustion in a gas turbine as mentioned), it is cleaned to remove impurities like ash particles, sulfur compounds, and other contaminants.
In summary, making coal gas from coal involves a controlled chemical process where coal reacts with specific agents under high temperatures, followed by essential cooling and cleaning stages.
