Transcript
Page 1: Sugar bleaching with ozone   preliminary tests

SUGAR BLEACHING IN AGROctober 2000

PRELIMINARY EVALUATIONby

H. Pareja, A.C. Moutella, R. Yoshida

Page 2: Sugar bleaching with ozone   preliminary tests

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.

Page 3: Sugar bleaching with ozone   preliminary tests

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.

Page 4: Sugar bleaching with ozone   preliminary tests

Test programbatch motor

inj. Sup inj meio sucção afogado tempo 3000 2000 1000 500 6% 10% rotação1 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

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/ agitaraval. red. de potência melhor condição

repetir melhor condição

para testes confirmatórios

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Page 5: Sugar bleaching with ozone   preliminary tests

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

Page 6: Sugar bleaching with ozone   preliminary tests

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).

Page 7: Sugar bleaching with ozone   preliminary tests

Main Results

0

50

100

150

200

250

0 20 40 60 80TIME (min.)

color

(icum

sa)T1T3aT4aT3bT4b

Page 8: Sugar bleaching with ozone   preliminary tests

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.

Page 9: Sugar bleaching with ozone   preliminary tests

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

0,0

0,5

1,0

1,5

2,0

2,5

0 20 40 60 80time (min.)

log Co

lor

T1 T3T4 T3T4 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., vortexT3 - Inj. Infer, vortexT4 - Inj. Infer, no vortex

Page 10: Sugar bleaching with ozone   preliminary tests

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

Page 11: Sugar bleaching with ozone   preliminary tests

0

50

100

150

200

250

0 500 1000 1500 2000 2500dosage (mgO3/L)

color

T1T3aT4aT3bT4b

Dosage and Color

Very low values were achieved

Page 12: Sugar bleaching with ozone   preliminary tests

Comparing to previous tests

0,0

0,5

1,0

1,5

2,0

2,5

3,0

0 2000 4000 6000dosage (mgO3/L)

log (C

or)log AGRlog conv.Linear (log AGR)Linear (log conv.)

AGR values lower than conventional

Page 13: Sugar bleaching with ozone   preliminary tests

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.(?)

Page 14: Sugar bleaching with ozone   preliminary tests

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.


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