CFBC, preferred Technology for lignite fuel - Experiences - Infraline

separate norms in respect of Auxiliary Power Consumption, reimbursement of complete
fuel additive charges, if necessary.
Introduction
India has total estimated usable lignite reserves of 97,000 MMT , concentrated in the
states of Tamilnadu, Gujarat and Rajasthan. Tamilnadu has 70,000 million Tones,
Rajasthan has15,000 million Tones, Gujarat has 12,000 million Tones. All these states
are far away from coal reserves located in India. It is economical to use lignite for power
generation in these areas. These are more than 30% of coal reserves available in India.
Estimated power generation capacity addition with this lignite reserves is around
3,00,000 MW for 50 years. India has not exploited lignite reserves available for power
generation as it has to be considering the available resources. Performance of units with
PF technology using lignite has been low. Performance of Units with CFBC
technology using lignite is encouraging.
CFBC operates with combustor temperatures in the region of 850 – 900 deg C. These
combustor temperatures are much lower than ash fusion temperature. So, in CFBC
boilers problem of any clinker formation is not encountered with lignite as primary fuel.
General quality of lignite fuel available for using in boilers in India is as follows:
Parameter Range
Total Moisture 40 to 52%
Ash 8 to 20 %
VM 21 to 34%
FC 11 to 20 %
CV
2500 to 4000 Kcal/kg
Sulphur 1 % to 6%
Chloride 0.20 % to .35%
ADVANTAGES OF CFBC TECHNOLOGY
Environment Friendly
Sulfur emissions are effectively controlled by adding lime stone to the fluidized bed,
eliminating the need for an external desulfurization process such as SO2 scrubbers,
which are costly. Because of reduced combustion temperatures, Nox emissions are
inherently low or negligible.
Fuel Flexibility
FBC units were touted as being “fuel flexible”, with the capability of firing a wide
range of solid fuels with varying heating value, ash content, and moisture content.
Combustion in FBC units takes place at temperatures below the ash fusion
temperatures of most fuels. Consequently, tendencies for slagging and fouling are
greatly reduced with FBC.