# Hydrogen as fuel

Hydrogen as fuel :

The heat of combustion of hydrogen is high $(\text&space;{242&space;kJ&space;mole}&space;^{-1})$ and hence hydrogen is widely used as an industrial fuel.

Oxyhydrogen blow torch :

When hydrogen is burnt with pure oxygen in oxyhydrogen blow torch a high temperature $(2800&space;^{\circ}\text&space;C)$ flame is obtained. It is used for welding purposes and for melting platinum and quartz.

Water gas :

A mixture of $(\text&space;{CO&space;and&space;H}_{2})$ obtained when steam is injected over a white-hot bed of coal or coke is known as water gas. The calorific value of gas is $\text&space;{13,000&space;kJ/m}^{3}.$

Uses of Water Gas :

• Water gas s used to remove carbon dioxide from fuel cells.
• Reacted with producer gas to make fuel gas.
• It is used in the process of Fischer-Tropsch.
• It is Used to obtain pure hydrogen to synthesize ammonia.

Carburated water gas :

The calorific value of water gas is increased by adding gaseous hydrocarbons to it. This enriched mixture is called carburated water gas.

Semi water gas :

A mixture of air and steam in appropriate proportions is passed through red-hot carbon. The heat generated by the combustion of carbon maintains the temperature necessary for the formation of water gas – by the action of steam on carbon which is endothermic. The gaseous mixture thus obtained contains hydrogen (10 – 12%); Carbon monoxide (25 – 28%); $\text&space;{CO}_{2}$ (4 – 5%); nitrogen (50 – 55%) and methane (1 – 2%). It is used as fuel in the steel industry. It has a low calorific value.