Coal tar processing plants are located in steel plants, coke production plants and coal extraction industries. Coal tar is obtained has additional product when coal is heated to high temperatures to make coke. Equipments like ovens or indirect furnaces are used for coal heating process, during the process chemical compounds vaporise from coal. When the vapors are condensed, along with lightweight hydrocarbons coal tar also condenses. By means of absorption techniques and density separation methods coal tar is removed from the uncondensed gas and liquid (obtained by condensation). Equipments like cone separators and electrostatic separators are used in the separation process system.
Here we discuss about how coal tar is processed further to obtain chemical like anthracene, wash oil, light oil, naphthalene and pitch,
Brief description how raw coal tar processed:
Coal tar contains water after the condensation operation performed to cool the coke oven gas. Decanting operation is done to separate the water from the coal tar because water does not mix with tar they settle in layers. Distillation is simple and favourable technique of separating hydrocarbons and so it is selected for separating the compounds based on the volatility. As shown in coal tar processing flowsheet, heating of tar by reboiler is not simples as the traditional distillation column design and so tar is heated in pipe still furnace and temperature is elevated to 125oC.