INSTALL SMART WALL BLOWING SYSTEM FOR OPTIMISING WALL BLOWING AND IMPROVING HEAT RATE
Background
The boiler performance including its ability to meet full load, auxiliary power consumption, net plant heat rate, availability of the unit, operation and maintenance cost etc are significantly affected by the fuel characteristics. Coal firing in the furnace form different kinds of deposits on the boiler tubes. To improve the performance and thermal efficiency of the boiler, it is important to remove the deposits periodically and maintain the heating surface clean. Boilers are designed such that the radiation and convective zone heat transfer surfaces
absorb the released heat proportionately. Any deviation in heat transfer in radiation and convection zone will affect the function of feed water preheating in the economiser, steam super heating in LTSH, platen super heater and final super heater. This will result in reduction in boiler operating efficiency.
Smart wall blowing system (SWBS) is a selective wall blowing system, operating on auto mode. The operation is controlled based on super heater spray flow and furnace heat absorption at different zones. The system helps to maintain the furnace heat absorption at optimum level thereby maintaining the super heater and reheater sprays within limits.
Present Status
The conventional wall blowing systems are operated sequentially once in 8 hrs. All soot blowers will be operated 3 times a day. In conventional blowing system, the furnace condition is not taken into consideration.
The changes in fuel characteristics and boiler load are also not taken into account for controlling the soot blowing. Periodical operation of the soot blowing system leads to significant variation in super heater and reheater spray. Soot blowing requires about 3.3 tons of steam per cycle.
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