FORECASTING THE FINAL RESOURCE OF THE REINFORCED CONCRETE CHIMNEY PIPE OF THE COKE CHEMICAL PRODUCTION

Abstract

A comprehensive study of the technical condition, corrosion processes, damage and load-bearing capacity of the reinforced concrete chimney pipe, which removes the gas-smoke mixture formed in the technological processes of coke-chemical production and is an aggressive environment, was performed. A methodology for predicting the remaining resource of the pipe structure has been developed. It was established that the damage that determines the ultimate resource is the collapse of the lining, after which active corrosion damage of the reinforced concrete structure occurs. An analysis of the composition and temperature-moisture regime of the aggressive medium was performed. It was established that it is gaseous, the most aggressive components of which are acid gases, the degree of aggressive action is moderately aggressive, possibly strongly aggressive. Corrosion of concrete progresses in a concentric front from the inner surface of the chimney to the outer surface at a rate of 1.2 to 4.8 mm/year. The corroded layer of concrete loses its strength and protective properties to the reinforcement. An analysis of the stress-strain state of the pipe taking into account corrosion damage was performed, the most heavily loaded dangerous zone and its structure were determined, and the limit values of the wall thickness and the depth of corrosion damage in this zone were determined, which ensure the fulfillment of the conditions for bearing capacity. Based on the values of the corrosion rate, the time to reach the limit state is determined. It is shown that without repair and protection measures, the remaining service life of the pipe does not exceed 11 years. It is recommended to carry out a major repair of the pipe as soon as possible with the elimination of damage and restoration of the lining, or no later than after 10 years to carry out the liquidation of the structure with the construction of a new one.