The document evaluates the feasibility of using ozone to bleach sugar in an agitated reactor (AGR), highlighting that while ozone application is effective, high consumption levels and off-flavors were observed at certain doses. Preliminary results show AGR performs better than conventional methods with a 30% reduction in ozone consumption, though further testing is necessary to optimize conditions and assess kinetics. Next steps include conducting additional tests with varying initial sugar colors and ozone concentrations.

1. SUGAR BLEACHING
IN AGR
October 2000
PRELIMINARY EVALUATION
by
H. Pareja, A.C. Moutella, R. Yoshida

2. 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.

3. 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.

4. Test program
batch motor
inj. Sup inj meio sucção afogado tempo 3000 2000 1000 500 6% 10% rotação
1 x x 60 x x 500
2 x x 60 x x 500
3 x x 60 x x 500
4 x x 60 x x 500
5 60 x x 500
6 60 x x 500
7 60 x x 500
8 60 x x 500
9 60 x x 500
10 60 x x 500
11 60 x x 500
12 60
13 60 300
14 60 500
15 60 500
16 60 menor
17 60 livre livre livre livre livre livre livre
18 60 livre livre livre livre livre livre livre
observ.teste
avaliar efeito conc. O3
nível reatorponto de injeção dosagem de O3 conc. O3
livre
sem O3
para definir melhor condição
operacional
otimizando cinética de ozonização
est. consumo energia p/ agitar
aval. red. de potência melhor condição
repetir melhor condição
para testes confirmatórios
melhor
melhor
melhor
melhor
melhor
melhor
melhor
melhor
melhor
melhormelhor
melhor
melhor
melhor
melhor
melhor
melhor
melhor
melhor
melhormelhor
melhor
melhor
melhor
melhor
melhor
melhor
melhor
melhor melhor
melhor
melhor

5. UPDATE
• Tests
– 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

6. Let’s 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).

7. Main Results
0
50
100
150
200
250
0 20 40 60 80
TIME (min.)
color(icumsa)
T1
T3a
T4a
T3b
T4b

8. 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, let’s see as a log graph.

9. Log evaluation
y = -0,0121x + 2,1548
y = -0,014x + 2,2801
y = -0,0162x + 1,9687
y = -0,0123x + 2,1154
y = -0,016x + 1,9798
0,0
0,5
1,0
1,5
2,0
2,5
0 20 40 60 80
time (min.)
logColor
T1 T3
T4 T3
T4 Linear (T1)
Linear (T3) Linear (T3)
Linear (T4) Linear (T4)
Best results
Despite lines seem to
equal. O3 dosage for
T4 was higher
T1 - Inj. Super., vortex
T3 - Inj. Infer, vortex
T4 - Inj. Infer, no vortex

10. 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
dosage

11. 0
50
100
150
200
250
0 500 1000 1500 2000 2500
dosage (mgO3/L)
color
T1
T3a
T4a
T3b
T4b
Dosage and Color
Very low values
were achieved

12. Comparing to previous tests
0,0
0,5
1,0
1,5
2,0
2,5
3,0
0 2000 4000 6000
dosage (mgO3/L)
log(Cor)
log AGR
log conv.
Linear (log AGR)
Linear (log conv.)
AGR values
lower than
conventional

13. 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
showed stability.(?)

14. 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.