Achieving More Reliable and Efficient Use of Multibarrel Smoke Stacks

Abstract

Stacks with steel barrels installed inside of a reinforced concrete shell are the most widely used type of multibarrel smoke stacks in Russia. The reinforced concrete shell of such stacks is protected against the effect of flue gases, and with correctly conducted operation, it can perform its functions for an almost unlimited period of time. The smoke stack main damages occur as a consequence of steel barrel corrosion, especially if flue gases contain sulfur oxides. The possibility to decrease corrosion of the smoke stack steel barrels by changing their operation conditions is considered. A new method for achieving more reliable and efficient operation of multibarrel smoke stacks is proposed, according to which the barrel shutdown corrosion is eliminated, and measures are taken for the smoke stack to help unload the exhaust fans to a greater extent through optimal use of the barrel stack effect. The main methods applied to decrease corrosion of the metal gas removing barrels used in multibarrel smoke stacks are considered. A new design of the metal barrel base part is proposed, which in the course of boiler equipment operation makes it possible to redistribute the gas flows among the smoke stack barrels. In addition, the smoke stack operation modes are proposed, in which the steel barrel shutdown corrosion is eliminated, and the exhaust fans are unloaded due to an increased total stack effect of the barrels. A computer program for calculating such operation modes has been developed. Variants calculations of the smoke stack operation mode performance parameters have been carried out with taking into account the real operation conditions. It has been determined that in the case of using the stack effect of the barrel from which the boilers are disconnected, the electricity consumption for driving the exhaust fans of operating boilers decreases by 5–10%; in addition, with such operation, the possibility of shutdown corrosion to occur in the smoke stack steel barrels is excluded.