Global demand for electrical energy is in constant growth because of the constant increase in the number of inhabitants and the economy growth. This paper presents the way the increasing demand for energy and the constant increase in the capacity of power plant production systems exacerbates the working conditions of the system parts and leads to the remaining working life reduction. Efficient operation of thermal power plants is the basis of economical production of electricity based on combustion of lignite. Ventilation mill as such is one of the basic equipment in thermal power plants which work has a significant impact on the level of energy efficiency. This paper presents the complexity of the optimization problem of the different thermal power plants and the system demands to use multidisciplinary research. However, any optimization of an energy plant, such as a ventilation mill, in this case, represents a unique approach to the problem of operating efficiency of the plant, and as such it asks for many new requirements and solutions. This paper also presents the way for solving this complex problem by using detail analyses of work of system of ventilation mill and dust channel by analysing the period of failures. This paper describes the following: the usages of CFD numerical simulation in FLUENT software for determining the working conditions in ventilation mill and dust channel; possibilities for use the process of coating damaged parts with wear resistance material and procedure for selection and coating on real working parts; analyses of damaged coated working parts of ventilation mill after testing in exploitation condition; data analysis of working parts before and after coating, time and time and resource saving. One of the main goals is to analyse the damaged coated working parts of ventilation mill after testing in exploitation condition.