If We raised the FSI value from 3 to 7, What will be happen to boiler operation?
FSI is A measure of the tendency of a coal to swell when heated under controlled conditions. Its interaction with boiler operations is summarized here: Coking coal is best if it has a very narrow range of volatility and plasticity. This is measured by the Free Swelling Index test. Tar content, volatile content and swelling index are used to select coals for coke blending. Volatility is also critical for steel making and power generation, as this determines the burn rate of the coal. High volatile content coals, while easy to ignite often are not as prized as moderately volatile coals; low volatile coal may be difficult to ignite although it will contain more energy per unit volume. The smelter must balance the volatile content of the coals to optimise the ease of ignition, burn rate, and energy output of the coal. Low ash, sulphur, and carbonate coals are prized for power generation because they do not produce much boiler slag and they do not require as much effort to scrub the flue gases to remove particulate matter. Carbonates are deleterious as they readily stick to the boiler apparatus. Sulphide contents are also deleterious in some fashion as this sulphur is emitted and can form smog, acid rain and haze pollution. Again, scrubbers on the flue gases aim to eliminate particulate and sulphur emissions.
