Consider the following substances :

I. Ethanol
II. Nitroglycerine
III. Urea

Coal gasification technology can be used in the production of how many of them?

(a) Only one
(b) Only two
(c) All the three
(d) None

The correct answer is (b) Only two.

Explanation

Coal gasification is a process that converts coal into synthesis gas (or syngas), which is a mixture primarily composed of hydrogen ([latex]H_2[/latex]) and carbon monoxide ([latex]CO[/latex]). This syngas is a versatile chemical building block.

Let’s examine the production of each substance:

I. Ethanol:(Can be produced) Syngas (the product of coal gasification) can be converted into ethanol through a thermochemical process or a fermentation process. Therefore, coal gasification can be used in its production.
II. Nitroglycerine:(Cannot be produced) Nitroglycerine is produced by reacting glycerol with nitric acid and sulfuric acid. Glycerol is typically derived from fats and oils (biodiesel production) or from petroleum. This process does not involve syngas, so coal gasification is not used.
III. Urea:(Can be produced) Urea ([latex]CO(NH_2)_2[/latex]) is produced by reacting ammonia ([latex]NH_3[/latex]) with carbon dioxide ([latex]CO_2[/latex]).
- Ammonia is produced via the Haber-Bosch process, which requires hydrogen ([latex]H_2[/latex]).
- Hydrogen can be separated from the syngas produced by coal gasification.
- Carbon dioxide is also a byproduct of the syngas cleanup process.
- Therefore, coal gasification provides the key feedstocks needed to make urea.

In summary, coal gasification can be used in the production of Ethanol and Urea, but not Nitroglycerine. This makes “Only two” the correct answer.

Learn More

What is Coal Gasification?

Coal gasification is a thermochemical process that takes place in a high-temperature/pressure vessel called a gasifier.

The Basic Reaction: [latex]\text{Coal (Carbon)} + H_2O \text{ (Steam)} + O_2 \text{ (Oxygen)} \rightarrow CO \text{ (Carbon Monoxide)} + H_2 \text{ (Hydrogen)} + \text{Byproducts}[/latex]

The resulting mixture, syngas, is a powerful intermediate product. Think of it as a “chemical lego block” that can be reassembled into many other valuable products.

Pathways from Syngas

Coal-to-Liquids (CTL): Syngas can be converted into liquid fuels like gasoline and diesel through a process called Fischer-Tropsch synthesis.
Coal-to-Chemicals:
- Urea: As explained above, the hydrogen from syngas is used to make ammonia, which is then combined with carbon dioxide to make urea for fertilizers.
- Methanol/Ethanol: Syngas can be catalytically converted into alcohols for fuel or chemical use.
- Hydrogen Fuel: The hydrogen can be separated and purified to be used in hydrogen fuel cells.
Power Generation: Syngas can also be burned directly in a gas turbine to generate electricity, which is often cleaner than burning the coal directly.