sugar bleaching with ozone preliminary tests
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SUGAR BLEACHING IN AGROctober 2000
H. Pareja, A.C. Moutella, R. Yoshida
OVERVIEW Ozone to bleach sugar proved to be
technically feasible in agitated reactor. However, consumption were high. No toxicity was detected at all, but At long contact time or high Ozone dosage,
off-flavors were noticed. To remove these off-flavors, additional step
applying CaCO3 was proposed.
Objectives Establish best conditions to AGR operation. Evaluate AGR performance to bleach sugar
with Ozone. Acquire kinetics information. Acquire parameters to scale-up Adjust O3 generator.
Test programbatch motor
inj. Sup inj meio suco afogado tempo 3000 2000 1000 500 6% 10% rotao1 x x 60 x x 5002 x x 60 x x 5003 x x 60 x x 5004 x x 60 x x 5005 60 x x 5006 60 x x 5007 60 x x 5008 60 x x 5009 60 x x 50010 60 x x 50011 60 x x 50012 6013 60 30014 60 50015 60 50016 60 menor17 60 livre livre livre livre livre livre livre18 60 livre livre livre livre livre livre livre
avaliar efeito conc. O3
nvel reatorponto de injeo dosagem de O3 conc. O3
para definir melhor condio operacional
otimizando cintica de ozonizao
est. consumo energia p/ agitaraval. red. de potncia melhor condio
repetir melhor condio
para testes confirmatrios
AGR pilot scale 200 liter nominal Ozone generator capacity: 1.5 Kg/h Ozone concentration: 5-7% 5 tests, 25 samples, 100 analysis
Product parameters color, Brix, pH and turbidity
Lets see the work Next, a graph represents the results obtained. It is important to notice that initial color shows a good
value of below 200 icumsa. Average values can be considered 400 and worst 800
icumsa These tests evaluated the best position inject ozone, if at
the entrance of the vortex or at the end of the draft-tube. It was also evaluated if the reactor would be work with
(favor headspace suction) or without vortex (favor internal recirculation).
0 20 40 60 80TIME (min.)
Confused? Although logical, the results are dificult to
evaluate. Color decreases quickly, but as it lowers the
value , the decoloring reactions reduces its kinetics.
It seems that this reactions has a logartimic behavior , like C = Co ekt.
So, lets see as a log graph.
Log evaluationy = -0,0121x + 2,1548y = -0,014x + 2,2801
y = -0,0162x + 1,9687
y = -0,0123x + 2,1154
y = -0,016x + 1,9798
0 20 40 60 80time (min.)
T1 T3T4 T3T4 Linear (T1)Linear (T3) Linear (T3)Linear (T4) Linear (T4)
Despite lines seem to equal. O3 dosage for T4 was higher
T1 - Inj. Super., vortexT3 - Inj. Infer, vortexT4 - Inj. Infer, no vortex
Too much math and info? Humm! Ok. Just take attention to these
observations: Log graphs are better to analyse this process. A straight line represents the process using an
AGR. But more data have to be collected. More inclined is the line, more quickly the
color decreases . Next we are going to see the effect of the
0 500 1000 1500 2000 2500dosage (mgO3/L)
Dosage and Color
Very low values were achieved
Comparing to previous tests
0 2000 4000 6000dosage (mgO3/L)
or)log AGRlog conv.Linear (log AGR)Linear (log conv.)
AGR values lower than conventional
Preliminary Conclusions AGR is better than conventional reactors for
sugar bleaching with ozone. During the tests initial color was very low. AGR reduces ozone consumption by 30%
under current test condition. AGR works stable. Ozone generator did not
Next work New tests have to be programmed with
higher initial color. Effect of higher ozone concentration has to
be evaluated. Kinetics will be evaluated. Process conditions will be defined.