Question

Semi water gas is:
A. water gas + producer gas
B. water gas + $C{O_2}$
C. producer gas + $C{O_2}$
D. producer gas + coal

Answer 1

Hint: Semi-water gas is produced by collecting the gas which is produced when steam is reacted with coke to maintain a very high temperature which can be used to carry out water gas reaction.

Complete step by step answer:
The water gas is usually a mixture of carbon monoxide and hydrogen which is obtained from synthesis gas. The reaction involved in the production of water gas is a water gas shift reaction where carbon monoxide is oxidized forming additional hydrogen. Same reaction can be used to obtain pure hydrogen from the water gas by removing access to carbon dioxide formed when carbon monoxide is reacted with water.
The water gas is formed by passing steam over red hot coke which results in a mixture of carbon monoxide and hydrogen.
The reaction is shown below.
$C + {H_2}O \to CO + {H_2}$
This reaction is an endothermic reaction as heat is absorbed during the reaction.
Water gas has many variations like Carburetted water gas and semi water gas.
The semi water gas is a mixture of water gas and producer gas which is obtained by passing a mixture of air and steam through a coke which is hot. When producer gas is formed, the heat generated during the formation keeps the temperature of the coke high enough so that the water gas can be formed.
So, the correct answer is “Option A”.

Note:
 The producer gas is the fuel gas which is derived from coal or coke. The carburetted water gas is formed to increase the value of water gas as it is lower than coal gas.