| The combustion of fossil fuels has caused serious ecological damage and environmental pollution. At the same time, the reserves of fossil fuels such as oil and coal are limited, but the rapid development of modern industry makes the speed of energy demand increased rapidly, so it is urgent to seek new renewable energy. As a substitute for fossil fuels,biomass fuel has received worldwide attention in recent years,there are many researches that biomass fuel used in internal combustion engine,but the researches that biomass fuel used in the industrial furnaces are few. The combustion flame characteristics of biomass fuel in industrial furnace were studied in this paper,to provide theoretical basis for biomass fuel used in industrial furnace, and to provide reference for industrial furnace design.Physicochemical properties of fuels are analyzed, the waste oil, jatropha oil and their biodiesel as the research object, and diesel as a comparison. The results show that viscosity of biomass fuels and diesel decrease with the increase of temperature. The change trend of viscosity of waste oil and jatropha oil is obvious. The kinematic viscosity of diesel and biodiesel is relatively small and the viscosity temperature curve is relatively flat, barely affected by temperature; Waste oil density, viscosity, surface tension, moisture content, sulfur content in the measured five kinds of fuels are the largest, and the calorific value and sixteen cetane number is the smallest, presumably waste oil not easy to ignite, and the combustion instable; The light distillate and middle distillate in biodiesel is lower than in diesel, that is, the evaporation and atomization of biodiesel and the low temperature flow are not as good as diesel. The heavy distillate in biodiesel is higher than in diesel, and at high temperatures, the heavy distillate is easy to crack, producing coking phenomenon.A self-designed biomass fuels atomization and combustion test platform is used to study the characteristics of the flame. Variation of the flame volume and flame length with atomization pressure and excess air coefficient is analyzed by using high-speed video camera and digital image processing technology and MATLAB programming software. Results show that:1) diesel fuel is easier to ignite, having the best stability and the largest flame volume, and its rising trend is obvious and more dispersed. The combustion flame of biodiesel under certain conditions is stable, flame volume being slightly larger; cooking oil and jatropha oil at the beginning of combustion is not easy to be ignited, presenting unstable combustion process and smaller flame volume.2) With the increase of excess air coefficient a or atomization pressure P, combustion flame volume and flame length of biomass fuels and 0# diesel in the furnace decreases. In the same condition, diesel flame length is the longest, followed by waste oil and biodiesel.Temperature distribution of flame region is studied by thermocouple. Results show that:1) Flame temperature of five fuels along the axis begins a slow increasing, rises into the rapid growth, reaches a peak and then decreases rapidly; Low temperature was found at axis. Temperature along the radial direction first increases, and then decreases. High temperature area upper axis is larger than lower axis.2) Diesel flame temperature is the highest of the five kinds of fuels,followed by biodiesel and waste oil.3) When excess air coefficient a increase in range of 1-1.4, mean temperature of the flame increase with the increase of excess air coefficient; When the excess air coefficient is more than 1.4, the average flame temperature decreases with the excess air coefficient increases.
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