Experimental Study On Basic Combustion Characteristic Of Raw Gas In Poly-Generation System

The poly-generation system, by making synthetic gas with the gasification gas and the pyrolyzation gas, is of the characteristic of hydrogen-rich gasification gas and carbon-rich pyrolyzation gas. With the reforming technology, the coke oven gas is effectively used. In this poly-generation system, the components and physic parameters of raw gas for generating electricity are variable with operating conditions. Therefore it is necessary to research the basic combustion characteristic of raw gas in order to insure the stable electric power output.Based on the gas combustion characteristic, the author analyzes not only the combustion form and feature for gas, but also the composition and property. According to the analysis results, the research on the gas combustion flame form, length and transmission velocity from two aspects of laminar diffusion combustion and premix combustion in theory has been carried on. The result indicates that the flame forms of laminar diffusion combustion and premix combustion are circular cone, and the flame length and transmission velocity are related to the gas velocity. Studying the characteristic of complete premix combustion is helpful to further understanding of the combustion characteristic for raw gas under diffusion and premix combustion.The main parts of raw gas are fluidized bed gasification gas and coke oven gas. The main components are H₂, CO, CH₄, also including a little of CO₂ and N₂. In the experiment, the raw gas consists of the combustible component of H₂, CO, CH₄ with certain proportion. According to the characteristic of gas combustion, the author carried on the design calculation for combustion chamber. Then the measuring instruments for the flue gas and temperature are selected according to the calculation results. The diffusion combustion experimental system is designed which adapts to basic combustion characteristic research of raw gas. This system consists of five subsystems, such as combustion chamber system, fuel gas system, air system, measuring system and smoke extraction system.The excess air coefficients affect the combustion degree, the final flue gas component and flue gas volume. Therefore, in the experiment, researches on combustion characteristic of raw gas have been done at different excess air coefficients. The experimental results indicate that the maximum radial temperature in combustion chamber reaches up to 1100℃. The position focuses in the center of combustion chamber or 5mm away from the center, and the temperature distribution is in symmetry near axis. Changing excess air coefficients will affect raw gas burning temperature and production severely. The larger the excess air coefficients are, the higher the combustion temperatures are. In the center of the chamber, the oxygen concentration is lower and carbon dioxide concentration is larger. Therefore, using reasonable excess air coefficient may increase combustion temperature and make raw gas burn completely.By the experimental study on raw gas combustion characteristic under diffusion combustion, we could give theoretical basis to raw gas combustion characteristic research in combustion of premix and adding catalyst. Moreover, the mathematic models for controlling catalytic combustion are established according to the obtained results.