how is desructive distillation of coal carried out?

Destructive distillation is defined as the process of heating coal strongly in the absence of air.

As a result of destructive distillation the coal does not burn but produces many by-products.

The apparatus used for destructive distillation of coal is given as:

The coal is heated in the absence of air resulting in the formation of coal gas, ammonia, coal tar and coke. Coal on heating strongly in the absence of air changes to coke. The gas that is released in the process is then made to pass through water. On doing this, some of the compounds get condensed and settle down at the bottom of the container. This is known as coal tar. However, some still remain in the gaseous state. These are collected as such and are known as coal gas.