Development of an Information Modeling System of Coal-Dust Fuel Injection into Tuyeres of a Blast Furnace

The article considers a mathematical model of the combustion zone of a blast furnace working with the use of the injection of coal-dust fuel. In this model, two subsystems were identified: (1) subsystem of heating the particles of coal dust and volatiles released in the combustion zone; (2) subsystem of heat exchange and combustion processes in the tuyere. A two-dimensional velocity field of gas in the combustion zone was investigated. The combustion processes are considered as a set of simultaneously developing phenomena of coke burning in a layer, single pieces of coke and particles of coal dust. The model includes the following equations: total gas mass balance, gas component mass balance, gas heat balance, movement of coal dust particles, and heat balance of coal dust particles. The model calculates maximum burning temperature in the combustion zone, the distance from the cut of the tuyere to the focus of combustion, the length of the oxygen combustion zone, gas temperature, the content of gas phase components, and the degree of carbon burnout of pulverized coal at the outlet of the tuyere combustion zone. An information-modeling system has been developed. It allows for the investigation of the influence of combined blast characteristics, the properties of coke and coal-dust fuel, the geometric dimensions of tuyeres, and other factors on the temperature fields and concentrations of components of the gas phase in the combustion zone. The model also helps to select a rational mode of pulverized coal that will ensure completeness of its combustion in the tuyere combustion zone. The main functions of the program are as follows: representation of results of calculation in form of tables and diagrams, storage of options of basic data in a database, and export of results of calculation to Microsoft Excel. Conclusions were made on the reduction of the combustion temperature in the combustion zone and the approach of the focus of combustion to the tuyere when pulverized coal was injected. The authors also have established the need to use coals with certain quality characteristics and place where coal dust was introduced into the blast stream.