h1. *ANC CONTROL*
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h2. *Experiment 1: Minimum amount of lime input in two reactors*
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h5h4. Introduction
In the first experiment of Spring 2010 team, the goal iswas to evaluate the lime feeder's performance inwith respect to its effluent pH with ifa theminimum lime input was based on theoretical value,calculations. whichThis wasis the mass of lime which would be consumeddissolve in 12 hours as a function ofgiven the flow rate and the calcium hydroxide solubility constant (equation 1.1), and different flow rate. As can be seen in (equation 1.2), the theoretical lime requirement wasis simply based on mass balance what could dissolve in twelve hours, and didn't take into account theother insufficientfactors usewhich oflimit limehow thatmuch wouldof occurthe byavailable thelime influentialwill ofactually other factorsdissolve.
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h5h4. Procedure
The team basically used basically the same procedure asdescribed describedin onthe materials and methods section, but it is important to address although the changelime of the design in which the lime wasis now fed through thea vertical tube.
As a comparisonSo that the experiment could be compared with the last experiment carried out by the Fall 2009 team (Experiment 3, Trial 4), the Spring 2010 team used the same flow rate, which was 40mL/min in both reactors, and a lime mass of 8gm based on the solubility calculations (figure 1.1). However, one thing has to be noticed is that the team feed powdered lime directly into the vertical tube without dissolving the lime in distilled water. One important change was that the lime in this experiment was fed dry, not mixed with water as a slurry. This may affect the particle size distribution, which is discussed in the hypotheses section.
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{latex}
\large
$$
[〖Ca〗^(2〖Ca〗^2+) ]× [〖OH〗^- ]=K_sp
$$
{latex}
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{latex}
\large
$$
Lime(Q)=(K_sp/〖[〖OH〗^-]〗^2 )×MW×Q×12hrs
$$
{latex}
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!Ks.jpg|align=centre!
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h5h4. Results and Conclusion
From the experiment data shown in figure 1.2: the A1 reactor could barely go above 12 and the A2 reactor maintained a pH over 12 for just over 2 hours. Compared to Trial 4, which the previous team used fine hydrated lime instead of powdered form in this run, the comparison parameter--lime input, could be a very important factor and further discussion is shown in (kinetic hypothesis). The experiment also showed that the A2 reactor could create a much better suspension than A1, which means its new geometry reaches our expectation, but the 40mL/min flow rate is far from the ideal velocity to get the best suspension. By kept changing the up-flow and observing the suspension in A2 reactor, the team assumed the optimum flow rate was 120mL/min, which around this level best suspension could be acquired in A2 reactor.
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!Exp 1.jpg|align=centre! | 