Development of a prototype crop residue burning machine
Abstract
The purpose of this study was to design, develop and evaluate a prototype crop residue burning machine that burns the largest area while maintaining burn uniformity. Additionally, the concentration of air pollutants and the machine cost was determined. Three types of burners were assessed mainly in term of the generated flame temperature. Two of the burners were forced draft burners and the other was a natural draft burner. The burner that generated the best flame temperature for agricultural residue burning was then used for developing the prototype. Six burners were placed in a pyramidal shape combustion chamber. The effect of burner angle, crop residue loading rate on burned area percentages and burned uniformity were determined. Both burned area percentage and burned area uniformity were analyzed using image processing. Moreover, a control system was designed to ensure the machine operates in a safe manner. To evaluate the combustion conditions of the experimental system, CO2, O2, CO, NO and NO2 concentrations were measured using an ECOM-EN2 flue gas analyzer. A Windows application was developed to systematically estimate the cost of the developed burning machine. Six forced draft burners with 3/8" mixing tubes were used to develop the machine prototype. This burner generated a flame temperature of 800-840oC at 20 PSI. This temperature range was recorded at 5" from the burner flare. The burner angle of 67o, fuel loading of 2.9 ton/acre and travel speed of 1.9 mph had the highest percentage of burned area and relatively a higher burned area uniformity. The designed control system was able to maintain flame temperature in between 100 to 1000 oC and the LPG working pressure of ±10% from the set pressure. The gas emission study shows a high concentration of O2 in the flue gas that suggests there was too much air was supplied for the combustion resulting in heat loss through flue gas. The cost of prescribed burning and the machine burning were comparable when the size of burn unit for prescribed burning was 134 acres. It indicates the potency of machine burning for small scale usage.
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- OSU Dissertations [11222]