Hydrogen as fuel

Hydrogen as fuel : 

The heat of combustion of hydrogen is high (\text {242 kJ mole} ^{-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 ^{\circ}\text C) flame is obtained. It is used for welding purposes and for melting platinum and quartz.

Water gas :

A mixture of (\text {CO and 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 {13,000 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 {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.