Bietin Y. Increasing the efficiency of low-power furnaces by means of jet-niche technology

The first chapter of the dissertation describes the means of organizing the working process of one of the types of industrial furnaces - low-temperature low-power furnaces. It is noted that the pulse mode of operation of burner devices and the furnace as a whole is promising. One of the main directions for improving the thermal efficiency of fire equipment is the use of new advanced fuel combustion technologies. Conclusions. Based on the above information, the following conclusions can be drawn: 1. The main tool for the creation and modernization of existing fire-technical objects (FTO) is the burner device (BD) based on combustion technology that meets all the requirements of efficiency, environmental safety and reliable operation of FTOs. 2. The jet-niche technology allows to modernize low-temperature furnaces of low power. The second section describes the methodology and methodology for conducting research on the experimental stands in laboratory conditions and industrial facilities. Conclusions. The designs and methods of tests on the experimental stands were described. The measurement errors were calculated. The third section describes the design and workflow of the cupcake baking oven at the Danish Haas-Meinсke factory. To evaluate the efficiency of the oven and compile its heat balance, a number of agreed parameters were measured. The analysis of the data obtained made it possible to calculate methane losses and carbon monoxide emissions in each of the studied modes. Conclusions. The existing BD with a twist of the oxidizer flow, which operates in a pulse mode during operation has large losses of pure methane from 10% to 40%. Excessive emissions of carbon monoxide CO were also recorded. In the fourth section, based on the studies described in the third section, the maximum load of the BD at a process temperature of 250 °C was calculated. It is shown that the existing BD does not correspond to its passport data. This indicates the need for its replacement or modernization. As an alternative, a burner SNT-11, which is similar in thermal capacity and implements the jet-niche gas combustion technology at the lime kiln KM-14 at Ilyich Iron and Steel Works of Mariupol, where six burners SNT-11 were used, was considered and tested. As a result of processing the test results, a flow characteristic of the SNT-11 burner was constructed, which shows that the range of stable operation of a single SNT-11 burner is from 1 m. cubic meter per hour to 40 m. cubic meters per hour. When comparing the consumption characteristics of the SNT-11 with the existing standard burner of the cupcake oven of the HAAS MEINCKE factory, it is shown that when replacing this standard burner with the SNT burner, fuel savings of up to 40% are possible in the transient modes of the oven. Conclusions. The operation of the basic module of SNT burners at the minimum power modes was investigated. The critical geometric parameters of the rectangular module of the BD burner have been determined, at which it is necessary to switch to the cylindrical shape of the pylon. Section five presents the design and description of the working process of wafer sheet ovens at the HAAS factory (Vienna) and the DOMINIK factory (Poltava). It was found that the use of microflame burners leads to a number of significant disadvantages, such as: local overheating of waffle ovens (uneven heating of waffle ovens, lack of finished products), overheating and destruction of bearings of waffle ovens wheels (can lead to machine shutdown). Excessive carbon monoxide emissions were also recorded. Conclusions. Taking into account the identified shortcomings of the considered ovens, methods for solving the identified problems were proposed: a scheme for modernizing these ovens based on jet-niche technology was proposed. A preliminary calculation of the required burner was performed. In the sixth chapter of the thesis, methods for eliminating the shortcomings of the organization of furnace processes in GOCMEN and HAAS furnaces were considered, and alternative BDs were selected. The calculation showed that the power of the SNT-11 module is extremely high, and the reduction of its geometric dimensions to reduce power is limited by the critical width of the BD equal to 50 mm due to the destruction of flow uniformity due to edge effects. This circumstance leads to the need to switch to a cylindrical burner, where there are no edge effects. To select the optimal parameters of the burner, mathematical modeling was performed, on the basis of which several cylindrical burners were created and studies were conducted to select the optimal burner. The optimal configuration of the BD embrasure was selected and its effect on the shape and length of the plume was revealed. Conclusions. Thus, the organization of furnace processes in furnaces: a) where the burner device operates in a pulse mode; b) and in furnaces where microflame combustion technology is used.