Available coal has a challenging content with very poor Low calorific value at about average 1150 kcal per kg, and approximately with 55% moisture, 20% ash, 1.5-4% sulphur content.
In the indirect coal firing technique, you dry the incoming coal/ lignite first in the coal mills with hot flue gas and then you send 30% of that pulverized wet coal into a second set of electrostatic precipitators (vapor/brueden filters at +62m boiler elevation ) for further drying with outgoing hot flue gas.
This “indirect firing” was borrowed from cement process; it might be called technology plagiarism, and its application can not be proven its usefulness after 20 years of interrupted operation. Steam Boiler operation was almost in mess, non-stop operation was not possible for 4 steam boiler units altogether. When they call that “indirect coal firing” as the great western technology, one cannot conceal smile.
E/Ps are out of service most of the time, and the 2 of total 4 stacks in operation pour huge fly ash into atmosphere. If E/Ps are not working properly in a thermal power plant, and furthermore if they have no flue gas desulphurization on the stacks, then it is our sincere feeling that those power plants have to be stopped for operation since their harm to nearby environment is greater that the expected gain in electricity generation to the national grid.
Thermal Power plant Unit-B is brand new, clean, and better, fully equipped with sufficient capacity flue gas desulphurization systems, with high capacity flue gas dust collecting electrostatic precipitators. There is almost no apparent dust on the existing stacks.
Haluk Direskeneli, Hamburg based Energy Analyst