Pyrolysis of Coal for Fuel Production: A Review of the Effect of Various Parameters on the Pyrolysis Behavior of Coal

Alternative energy and renewable sources received considerable attention  from many researchers because fossil fuel has intermediate products during the conversion of coal. Intermediate products such as synthesis gas, biochar, and condensable vapors are directly influenced by the production of energy to mitigate the barrier to future energy demand. The present review deals with the pyrolysis of coal and the results of pyrolysis of coal investigated by the parameters affecting product distribution such as type of reactor, feedstock composition, temperature, heating rate, particle size, and sweeping gas flow rate. Intermediate products such as charcoal obtained at 300 to 400°C usually the product of a slow pyrolysis process because coal has a large content of un-burnt inorganic compounds in the form of NOX, SOX, and ash, bio-oil depend on volatile matters and obtained at temperature range 410 to 460°C as a product of fast and flash pyrolysis process because of high heating rate but during slow pyrolysis limited fraction obtained, gas formation observed when secondary cracking of coal at a temperature relatively higher to 500°C.  Environmental effects and part of the potential scope of coal pyrolysis-based studies are also discussed in this review. Therefore, in the future utilization of coal will be interesting to optimize the products.