Rotary kiln quality appraisal

Rotary kiln, also called rotary kiln or rotating bed kiln, is a cylindrical object with a certain slope, with a slope of 3 to 3.5%. The rotation of the kiln is used to promote the mixing of materials in the kiln, so that the materials are mixed and contacted with each other to react. During operation, the coal injection combustion at the kiln head generates a large amount of heat, which is transferred to the materials for calcination through flame radiation, hot gas convection, and kiln brick (kiln skin) conduction.
In the case of rotary kiln quality appraisal, quality appraisal of all aspects of the entire project is an essential link. Zhongke Testing provides rotary kiln quality appraisal services.

GB/T 32994-2016 Rotary kiln for cement industry
GB/T 26282-2021 Determination method of thermal balance of cement rotary kiln
GB/T 34196-2017 Guidelines for energy efficiency assessment of grate machine-rotary kiln pellet process
GB/T 26281-2021 Cement rotary kiln heat balance, thermal efficiency, comprehensive energy consumption calculation method
JB/T 13389-2018 Industrial rotary kiln infrared scanning temperature monitoring system technical specifications
JB/T 8916-2017 Rotary kiln
JC/T 333-2006 Rotary kiln for cement industry

A company built a cement clinker production line. During the installation process of the rotary kiln of this project, a quality accident occurred where the cylinder cracked. An appraisal agency was specially entrusted to conduct a quality appraisal of the project. The
expert team arrived at the site for investigation. Through on-site inspection and analysis of the production process, they believed that the main cause of the accident was that the construction unit did not strictly follow the process assessment construction procedures during the on-site construction. The specific problems are as follows:
1, manufacturing problems:
The steel plate of this section of the cylinder is relatively thick and is a pearlitic heat-resistant steel. Due to the high carbon content and alloying elements, the material is relatively brittle. During the cylinder rolling process, it is usually necessary to adjust the roundness of the longitudinal weld on the plate rolling machine. Therefore, it needs to be rolled back and forth several times, which may cause the bending stress of the steel plate in this part to be too concentrated.
2, construction problems
1) The outlet method is incorrect: the overlapping plate used for the
two-section cylinder set does not meet the design requirements. After the construction unit lost the overlapping plate provided by the equipment manufacturer, it processed a piece of its own and replaced it, but there was no release hole. As a result, the welding stress could not be released during welding, and the stress inside the cylinder was concentrated, posing a hidden danger for cylinder cracking.
2) The welding quality of the overlap plate is unqualified: the welding point of
is too close to the edge of the cylinder, which makes the welding stress a weak point to release; the welding bite is serious, causing stress concentration inside the cylinder. 3) During the welding process of the lap plate, the construction procedures of the process assessment were not carried out. Under the alternating action of the internal and external stresses of the rotary kiln barrel, the stress was released at the weak point (the welding point), causing a quality accident in which the cylinder cracked.