RESEARCH ON THE REASONS FOR PREMATURE DESTRUCTION OF BOILER PIPES WHEN OPERATING IN A BOILER

Purpose is to establish the reasons for the premature failure of low alloy steel boiler tubes operating in a waste heat boiler in the ammonia synthesis workshop. Methodologies. The work performed: chemical analysis of low-alloy pipe steel on a spectrometer "SPECTROMAX" company "SPECTRO", Germany; visual inspection and study of the surfaces of boiler pipes using a scanning electron microscope REM 106 I; metallographic studies of the structure of steel along the cross section of completely destroyed and non-destroyed pipes; tensile testing of pipe mechanical properties. Results. Based on comprehensive studies, an unsatisfactory initial structure of boiler pipes was established, characterized by pearlitic banding of score 4 and fine grain No. 7−8, as well as a significant change in the structure of steel during operation of pipes in a waste heat boiler in an oxidizing furnace gas environment at elevated temperature and pressure. Based on comprehensive studies, a significant change in the structure and properties of low-alloy pipe steel was established during the operation of boiler pipes in a waste heat boiler in the environment of furnace gases at elevated temperature and pressure. Scientific novelty. It is scientifically substantiated that the cause of the destruction of boiler pipes is the degradation of the structure of low alloy steel, which consists in its decarburization and internal oxidation as a result of physicochemical processes occurring in an oxidizing medium at high temperature and pressure. It is scientifically substantiated that the cause of the destruction of boiler pipes is the degradation of the structure of low alloy steel as a result of physicochemical processes occurring in the environment of furnace gases at high temperature and pressure. Practical relevance. An accident associated with the explosion of a waste heat boiler with unfavorable environmental consequences and possible human casualties was prevented at the chemical industry enterprise. Recommendations are given on improving the operational reliability and durability of boiler pipes without capital expenditures.