WHY UPGRADE?
The Rotary Air Preheaters capture and recover ~60% of the heat energy leaving the rotor, The Rotary Air Preheaters capture and recover ~60% of the heat energy leaving the rotor, that otherwise would have been wasted. For a medium-sized 500MW boiler, this means fuel savings of 1500 tons/day, and the investment in the application of the preheater pays off after a few months. Rotary Air Preheaters represent more than 10% of the thermal efficiency of the entire combustion process. Such significant figures prove that it is not worth saving on preheaters, it simply is not viable.
What can be done:
- reduce air leaks to the flue gas by upgrading the seals and wing sealing systemsthe main purpose of the modernization of the rotary preheaters. Better sealing of the rotor causes significant relieving of the flue gas and draft fans, and consequently lower power consumption, increases the efficiency of the electrostatic precipitator as a result of the reduction of the oxygen content in the flue gas and slowing their flow, reduces heat loss and costs of annual overhauls.
- replace heating basketschange of the basket filling allows for raising the temperature of the hot air, while maintaining temperature of the flue gas or allowing only a slight drop of it. The new fillings are more resistant to contamination, with greater heat capacity. Application of new heating baskets reduces thermal energy losses and the benefits of their application are consistent with minimizing leaks.
In addition to the obvious direct impact of the use of new heating packages and reducing leaks, there are also indirect effects, that are not always known to a potential client:
–degradation of the devices intercepting air pollution after the Rotary Air Preheater (electrostatic precipitators, bag filter station) due to the reduced power of fans and a reduction in the gas flow is slowed down,
increase of primary air temperature and consequently increase of the coal pulverizer capacity,
– reduced emissions of NOx oxides and reduced losses of ignition,
– greater stability of the flame along with a smaller boiler load,
– a higher temperature means reduced corrosion of ZK baskets.
- zto ensure trouble-free operation - by upgrading drives, checking the rotor bearings.
- automate the rotor sealing – by application of the radial wings tracking control system, which allows unattended operation and reducing air leaks to the flue gas.
- prevention is better than cure - in order to ensure trouble-free operation, during the period of repairs carry out preheater annual overhauls, check control systems, condition of seals, housing and rotor tightness, assess and eliminate occurring problems in the bud.