ANALYSIS OF THE INFLUENCE OF THE ADDITIVES OXYGEN IN THE VAPOR OXIDANT TO THE COMPOSITION OF THE SYNTHESIS GAS FROM SOLID FUEL CONVERSION
A universal method of processing low-grade coals, as well as energy waste, is their gasification. There are different modes of solid fuel conversion that are possible in the process of gasification. As reacting agents, steam, oxygen (as well as their mixture), or air may act. Involvement of oxygen in the process of gasification makes it possible to accelerate and increase the stability of reactions occurring during the conversion. The authors considered a mathematical model of the conversion of coke placed in a cylindrical capsule, through which a steam-oxygen is blown. Fuel ignited due to the heating of steam-oxygen mixture to a certain temperature. The task was to determine the composition of the synthesis gas during the conversion of coke and analyze its composition, depending on the quantitative oxygen content in the steam-oxygen oxidizer. As it was shown by numerical calculations, an important parameter in this case is the fraction of oxygen in the oxidant. At a mass concentration of oxygen up to 0.1, the volume fraction of the combustible gas is about 22 to 75%; there is a lot of water vapor, the volume fraction of which is approximately 75-19%. The products of gasification contain a small amount of carbon dioxide. When mass concentration of oxygen in a steam oxygen oxidizer is more than 0.15, a synthesis of gas consisting of hydrogen and carbon monoxide occurs; with further increase of oxygen volume, the volume fraction of hydrogen begins to decrease, and carbon dioxide continues to grow. The increase in the volume fraction of coke, more oxygen must be added to the water vapor in order to obtain a synthesized gas of the same composition. It was found that with the certain concentration values of oxygen in the steam-oxygen oxidizer, it is possible to obtain synthesis gas with a specified percentage of combustible components.