EXPERIMENT 3
In order to overcome the difficulties faced at the end of the second experiment, the team considered a new design, which consists of a diagonal column attached at the top of the vertical column. The design would help the saturated lime-water solution stay inside the apparatus, while still having the needed concentration at the exit. Since the velocity in the slanted tube is affected by the angle, its vertical component is lower than the upflow velocity of the primary column. This decreased velocity allows more lime to settle back into the column and thus prevent unnecessary lime loss. Thus the primary column would be used as a storage vessel for the suspended lime bed while the slanted tube above it would allow for a more uniform saturated lime mixture.
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- When elementary lime particles coagulate, the density of the larger mass stays the same as that of the original particles. This is unlike what happens in flocs, that have a Dfrac of 2.3.
- Density of lime is 2.211 g/m^3: Particles are uniform.
- Shape Factor of lime particles = 1: The lime particles are perfectly spherical.
- Settling velocity = 10 m/day: Given a flow rate of 80 mL/min (as determined by Trial 1). This velocity corresponds to the finer lime particles that have a diameter of about 1 micrometer.
CALCULATIONS ANALYSIS
Theoretically, the maximum length of the tube should not exceed 1.5m. Lime particles will have a larger density than the flocs, which means their settling velocities will be higher than the assumed 10m/day. Also, it is not necesary that ALL lime particles settle down - some amount (not determined yet) will have to fall out of the lime feeder to solve the acidity problem. Consequently, the length of the tube needed will be lower than 1.5m.
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