Prelimer suspended solids can be separated. - ASSBT Proceedings

Note that with the high speed pump the fi ltrate recovered is nearly doubled v hen
filtration is ahead of the p ump. It will also be seen that four times as much suspended
solids were removed. Tbis is surely strong evidence of degradation of the fragile tl oc
particles by the shear of the high speed centrifugal pum p. Wi th the variable speed pump
significant improvement is shown. Still, the fi ltrate olume is 28% greater before the
pump, and the solids removal is 50 percent greater. The evidence indicates that the
gentlest possible handling of the effluent is imperative.
We had one opportunity to check out our theory that, with our polymer separation oftbe
suspended solids at the Prelimer, double carbonation would be unnecessary. We
obtained a large sample of the M ainlimer effiuent to 1st Carb and batch carbonated the
sample in the laboratory_ As the batch carbonation proceded, sampl s were removed for
analysis. The pH, limesalts, purity, and color was determined for each as shown in the
following Table, Table 3.
TABLE 3
BATCH CARBONATION OF MAINLIMER EFFLUENT
pH LlMESALIS PURITY COLOR
11.9 0.194 43 1
11.2 0.111 93.2 ] 83
10.7 0.068 92.7 83
10.3 0.064 93.4 91
9.9 0.043 93. 2 63
9.4 0.063 93 .2 70
Since this is infonnation from only a single laboratory sample, e surely cannot claim
any proof ofanything. We can, however say that the data give an indication that we
could indeed eliminate the nonnal double carbonation. The nonnal 2nd Carb pattern of a
minimum limesalts is indicated, although at a pH of 9. 9--higher than the usual 9. 2-9.4 or
so. The purity appears to be essentially constant, as it should be with only minimal
elim ination of nonsugars. And the color pattern is also about norma l. We e en got the
minimal color at mini mum limesalts in the test. Hopefully the premise ofthe single
carbonation will soon be resolved at the plant level.
Using assumptions that I felt were reasonable, I made something of a quick economic
analysis which indicated that , despite the very poor lime waste losses, the periods of
testing may well have been profitable. Obviously, the polymer technology will never be
adopted until good profitability can be demonstrated. I would li ke to see some of the
plant people study the economics thoroughly. In my opinion the potential for this
technology is great. It only stands to reason that nonsugars, particularly the fluffy, sticky
ones should be removed from the process stream as quickly as possible. Removal at the
Prelimer is at the first processing step.
96
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