Energy from Waste for Power Generation:
Crop residue, vegetable waste, water hyacinth, poultry droppings, animal manure, algae, ocean kelp, domestic waste etc., are said to be waste or biomass. Energy can be derived from this waste so as to keep environment clean and as well as convert energy for useful purpose such as production of charcoal, heavy oils etc., Different methods are discussed below.
Pyrolysis is defined as an irreversible chemical change brought about by heat in the absence of oxygen. During pyrolysis biomass undergoes a sequence of changes and normally yields a mixture of gases, liquids and solids. The solid is called charcoal, while the condensable liquid is called by various names such as pyroligeneous liquid, liquor, acid or pyrolysis oil. Pyrolysis in which charcoal production is maximised by slow heating is called carbonization. Pyrolysis can also be carried out in the presence of small quantifies of oxygen (gasification), or water (steam gasification) or hydrogen (hydrogenation).
When pyrolysis is carried out in the presence of hydrogen, the process is called hydrogenation. Under less severe conditions of pressure and temperature (100 atmospheres and 300° - 400°C), carbonmonoxide and steam react with cellulose to produce heavy oils. These oil can be separated and refined to produce premium oils.