| OCR Text |
Show Under the combustion conditions, the high bed temperature decreases the air density and thus the same mass flow of air has a higher velocity. Further, the viscosity of air increases as the bed temperature increases. This leads to the fluidization of bed at lower air flows. It was found that during the experimental conditions, fluidization was achieved at air flow rates of 4.4 1/s (560 FPH). 3.2 Combustion Experiments Experiments were undertaken to determine the effects of the following parameters on the combustion of feedlot manure: 1) Percent excess air 2) Bed temperature 3) Degree of fluidization (air velocity, U/minimum fluidization velocity,Umf ). Three sets of experiments were performed to study the effects of each of the parameters. The base conditions taken were: 32% excess air 650°C bed temperature, and air velocity of 1.46 times the minimum fluidization velocity. 3.2.1 Experimental procedure 1) The bed material (sand) is first loaded into the bed such that the sand bed height is kept at 0.46 m. 2) The preheating is started by setting the electric heaters at 90% and air flow at about 0.5Umf . 3) When the required sand bed temperature is achieved, the air flow (U) is set as required and the manure feeding is started at a controlled rate. 4) The desired water flow rate is then set for the water quench system (to cool the exhaust gases and to collect the sand and fuel 2.4.14 |
