The earliest attempts to produce coke date back to the closing years of the 16 th century.
Big sized coking coal was at first used for making coke. This was simply placed in a shallow but wide pit and heated for a number of days.
The 18th century saw the introduction of the muffle furnaces.
These were small furnaces with a walled structure which were able to reach higher temperatures.
By using this type of furnace, smaller sized pieces of coking coal with a tendency to agglomerate less could be utilised.
Furthermore, it was now possible to recover by-products such as tar and ammonia from the process.
Towards the end of the 19th century, coke ovens underwent further developments of great importance, affording additional benefits.
In particular, some of the surplus gas that resulted from making coke was also utilised.
In actual fact, it was already partly being used to heat the muffle furnace and also utilised for the burners of boilers for steam production.
But now it became more profitable to use it as fuel for internal combustion engines and as a gas for lighting.
With the advent of electricity and the loss of certain markets for this gas, steps were taken in the early part of this century to make full use of gas for heating coke-making ovens.