© P.Kadlec - Sugar 2015 1


Sugar Technology


Start of industrial sugar production in Czech - year 1831

Sugar production in CR - 500 thousands t per year

- domestic consumption 400 thousands t per year

Production costs

The important costs:

price of sugar beet 53 %

transport of beet 7 %

production costs in sugar factory 36 %

storage of sugar 4 %

SUGAR PRODUCTION IN CR

AND IN THE WORLD


CHOSEN CHARACTERISTICS

OF SUGAR BEET AND SUGAR

PRODUCTION IN CR

CR EU

Sugar beet yield (t/ha) 70-80 85

Area on 1 farmer (ha) 80 10

Content of sugar (%) 18.3 18-20

Yield (%) 87 87

Yield of refined sugar (t/ha) 11.5 11-14

Av.capacity of sugar factory (t/d) 5100 8000

Maximum sugar beet yield in France - more than 90 t/ha for content of sugar

16 %,

in CR 80 t/ha for content of sugar 16 %.

Yield of refined sugar:

France 14–15 t/ha, Switzerland, Belgium, The Netherland 12–13 t/ha

Great Britain, Denmark, Germany, Austria, CR more than 11 t/ha


WORLD PRODUCTION AND CONSUMPTION OF

SUGAR

20 % FROM SUGAR BEET

production

consumption

(thousands t)


SHARE OF WORLD SUGAR PRODUCTION ACCORDING TO CONTINENTS


World prices of sugar do not reflect of production costs

it is followed by: market mechanism of the offer and request

situation in world sugar reserves

Oscillation of world prices of sugar on stock market

White sugar Raw

sugar


SUGAR and its use · in human nutrition

· to chemical and biochemical transformations

Very long time of storage (years)

Relative low price

SUGAR AS FOOD

· to ensure the significant portion of total energy intake

· large offer of industrial and workshop produced foods

direct household consumption of sugar

Function of sugar:

· sweetener

· flavour

· conservation media

· matter giving of food volume

· matter finishing of food texture

substrate of fermentation

Consumption of sugar in CR - 35 kg per head and year

Recommended consumption according to Health Nutrition:

60 g/day, it is 22 kg/year

High sugar consumption and health diseases


SUGAR AS RAW MATERIAL

FOR CHEMICAL AND BIOCHEMICAL TECHNOLOGIES

· only 5 % of sugar world production is used for nonfood use

· products of chemical or biochemical transformations of sucrose are

biological degradable and are not toxic

The possibilities of production coming out from sucrose:

¨ fermentation to bioethanol, the following use as fuel or additives to

fuel

¨ clasical fermentation production (spirit, yeasts, organic solvents and

acids (citric, lactic), vinegar, aminoacids)

¨ products of chemical transformation of sucrose (sorbitol, vitamin C,

gluconic acid, 5-hydroxymethylfurfural, …)


BASIC ANALYTICAL TERMS

Dry substances S (%)

Sucrose P (%)

Nonsugars N = S - P

Purity Q = P/S . 100

Ash A (%)

Reducing substances, RL (%)

Invert sugar


Sugar beet

- Cultivation to maximal content of sucrose

- In conditions of good earth (soil)

- In mild climatic area

- For long vegetation time

- Area of earth suitable for growing of sugar

beet in CR 700 thousands ha

- Sugar beet is growing on area 60 thousands ha

- surrounding of rivers Labe, Vltava, Ohře,

Haná

- south Moravia, Opavsko (Silesia)

SUGAR BEET


Composition of a typical sugarbeet

Sugarbeet

75% Water 25% Dry substance

18-20% Beet juice 5% Beet marc

17.5% Sucrose 2.5% Nonsucroses

1.1% Nitrogenous 2.4% Pectin

(0.2% amino acids, 0.1% betaine, etc.) 1.2% Cellulose

0.9% Non-nitrogenous 1.1% Hemicellulose

(0.3% invert sugar, 0.2% raffinose, etc.) 0.1% Protein

0.3% Minerals 0.1% Saponin

(K+, Na+, Ca2+, Mg2+, SO42−, PO4

3−) 0.1% Minerals

0.2% Others


Modern sugar beet laboratory determination of soil content (mineral matters) and green plants materials

analytical determination sucrose (sugar)

natrium and kalium

amidic nitrogen

calculation of preliminary yield of refined sugar, resp. losses of sugar in

molasses according of composition of sugar beet

polarimeter Flame

photometer spectrophotometer

sample

dilutor dilutor

converter


Beet stock

Ballast separation

Stones, sand

Trash

Water

Washing

Slicing of cossettes

Extraction

Water Treatment of water

Soil mud

Water

Disinfection agents

Pressing

Pressed pulp

S=20%, P=0.5% Raw juice

Q=86-90 %

Conditions of extraction: temperature < 80 °C, time < 120 min, pH 5.8

HANDLING OF BEET AND RAW JUICE EXTRACTION


Material balance of the diffusion process

m1S1 = m2S2 + m4S4 m1P1 = m2 P2 + m4 P4

calculation of draft m2 (% beet)

S4 P1 - S1P4

m2 = ---------------------- . m1

S4 P2 - S2 P4

usual value of draft of raw juice 105-115 % beet

Extractor Water - 3

Pulp - 4 Cossettes - 1

Raw juice - 2


Extractors Tower

Slope

Drum

60 °C 74 °C

74 °C 72 °C

Slope extractor - scheme of measurement and control

SŘ – cossettes; SŠ – raw juice; VŘ – pulp; ŘV – pulp press water;

T – temperature; F - flow rate; L – level; I – indication; C - control

steam

water


Microbial contamination during extraction

Source of unknown losses – about 0.1 % or more

Sources of microbial contamination:

rest of soil on surface of beet

transport and wash water

fresh water

chiefly pulp press water

Raw juice is ideal mediums for microorganisms activity

contents of sucrose, aminoacids, amids, organic acids,

proteins, pectins, …

pH is about 6.0

temperature 30-75 °C

Aerobic and unaerobic soil bacteria decomposite the

carbohydrates

the main degradation product is lactic acid

pH of juice decreases under 5.8 (at 20 °C)

formation of gases

reduction of nitrates to nitrites


Pulp

Pulp pressing dry matter 15-25 %, max. 30-35 %

effectivity of pressing depends on:

physical properties of cossettes


pH 5.8-6.0

The lower pH – the better pulp pressing

Influence of soluble pectin and

its decomposition products

Pulp Dry Use

matter (%)

Low pressed 10-15 direct feeding, ensilage

High pressed 19-25 ensilage (min. losses, high

quality)

Dried 88-90 granulated fodder, pelets

Beet fiber 88-90 supplement of fiber for

human nutrition (dietary

substance; prevention of

civilizing

deseases)

PULP


pulp S=18-22 %

air 20 °C

barometric water

heated

air

50-55

°C

output air saturated

by water

predried pulp S = 40-45 %

Pulp drying •too high expensive process as regards of power consumption

•ways how to reduce energy consumption during drying of pulp:

•Maximal mechanic dewatering by pressing (power consumption is 60 kJ/kg

water in comparison with 3000 kJ/kg water for thermal dewatering)

•Predrying of pressed pulp to dry substance 40-45 % by using of waste heat of

barometric water or condensates

•Use of preheated steam for pulp drying

Dried pulp is used to preparation of fodder mixtures and pelet fodders


Raw juice

Dry matter 15-18 %

Purity 86-90 %

pH 6.0-6.3

Colour grey-black

Contains sucrose

colloid dispersed substances

pectines

proteins

colour matters

saponins

the others nonsucros


Juice purification

Main objectives:

1) To remove about 30 - 40 % of nonsugars

2) To neutralize the acid reaction of raw juice

3) To minimaze degradation of sucrose

4) To disinfect of juice

5) To remove fine pulp particles

For purification of juice is used:

· lime milk (hydrated suspension Ca(OH)2

and CaO in water)

· kiln gas (content about 30 % vol. CO2)


Raw juice, Q=86-90 %

Preliming - pH 11

Main liming – pH 12.5

1st carbonation – pH 11

Thickening of slurry

Filtration

2nd carbonation –pH 9-9.5

Filtration

Lime milk

Lime milk

Kiln gas – CO2

Kiln gas – CO2

Carbonation lime; mud

Thin juice, Q=90-94 %

P<1 %; S=60-70 %


Steam production Use of steam

to production of electric energy

to multiple evaporation of juice in evaporation plant and using of vapor for

heating in technology

boiler feed water

condensate feed

boiler

steam-

boiler

superheated steam

steam

reduction

station

reduced

steam

steam

saturator and

cooler

return

steam

steam to

evaporation

station

electric

generator


Juice evaporation

The main goal of evaporation station:

1. to concentrate of juice to 60 - 65 %

2. to supply production units with needed steam for heating

Quantity of evaporated water mw (% b.)

mw = m1 (1-S1/S2)

For m1 = 120 %, S1 = 16 %, S2 =65 %, then mw = 90 % b.

To evaporation of mw kg water is need the heat Qw

Qw = mw . r (kJ)

where r is heat of water evaporation at temperature t (kJ/kg)

Rough presumption: to evaporation of 1 kg water from juice heat-up

to boiling point is consumption 1 kg of steam


Vapor

Noncondensable

gases

Condensate

Juice feed

O

d

v

o

d

š

ť

á

v

y

Juice outlet

Steam

Robert evaporator

splash head

tubes


Scheme of evaporator station

Thin juice

S=15 %

Thick juice

S=65 %

to steam boiler plant hot condensate

to barometric

condenser


Crystallization process

1) nucleation (formation of nuclei/seed)

2) crystal growth

· need conditions for nucleation and crystal growth is existence

of supersaturated sugar solution

· driving force of nucleation and crystal growth is difference

between actual concentration in solution and

concentration of saturated solution (supersaturation)

Supersaturation of sugar solution is expressed as

supersaturation coefficient Kp

Kp = H/H1,

H - weight ratio P/W in solution

H1 - weight ratio P/W in saturated solution

growth rate of crystallization in steady state v

v = K . (Kp - 1)

K constant of crystallization

CRYSTALLIZATION OF SUGAR


Metastable zone

no creation of new nucleus, only

growth crystals

zone of supersaturation suitable

for evaporation and cooling

crystallization

limits of metastable zone are

influenced chiefly by temperature,

purity and presence of crystals

the lower limit correspond to

saturated solution


1-reservoirs

2-vacuum pan

3-barometric

condenser

4-crystallizer

5-distributing

trough

6-centrifuge

7-sirup

8-sugar

SUGAR BOILING

massecuite

evaporation

crystallization

in vacuum pan

cooling

crystallization

centrifugation


Automatization of sugar boiling

the main input - supersaturation

auxiliary quantities – crystals content, level in pan

To expression of supersaturation is used:

electric conductivity

viscosity (consistence)

Course of viscosity during sugar boiling


Conventional massecuite boiling 1) Preparation

2) Concentration 3) Seeding 4) Stabilization of nuclei

5) Crystal growth

6) Concentration

7) End of boiling

Boiling of massecuite with magma inoculation seed 1) Preparation to boiling

2) Seeding of inoculation magma – mixture of B/C sugar + crystal sirob

3) Crystal growth – boiling

4) Concentration of massecuite

5) End of boiling

Advantages:

Improving of grain size analysis of boiled crystal

Energy saving (steam) during shortened time of boiling

Simplification of boiling scheme


vacuum pans control room

crystallizers centrifuges


A-massecuite Thick juice

White Green A-sugar crystal syrup crystal syrup

Magma B-massecuite Magma C-massecuite

B seed C seed

B-sugar Green C-sugar Molasses B-syrup

B-magma C-magma

White Green White Green

B-aff.syrup B-aff.syrup C-aff.syrup C-aff.syrup

1st aff.sugar Thin juice 2nd aff.sugar

or water

Liquor


Molasses

Composition: S = 80-85 %, Q = 60 - 65 %, A = 10 %

pH > 8,3

Use of molasses 1) as animal fodder

2) raw material to biotechnology

- fermentation production (spirit, yeast, fodder yeast, organic acids - citric,

lactic, vinegar, organic solvents, aminoacids)

- modern biotechnological production

3) isolation of nitrogen substances (betaine, aminoacids, …)

4) desugaring process

- separation of sucrose as calcium sacharate - Steffen process

- Separation of nonsugars by means of ionexchangers - demineralisation or

ione exclusion

- sugar fraction is treated as liquid sugar

- nonsugar fraction is treated as fodder or fertilizer


Raw sugar (B, C)

Magma preparation

Affination

Liquor preparation

Filtration

Decolorization

Liquid sugar

Boiling of massecuite

Centrifugation

Drying

end moisture 0.05 %

Classification of crystals

Milling Packaging Pressed

cube

Scheme of refinery


Sugar screening

Screening maschine

Vibrating screens

Minimal content of the main fraction for sugar crystal and powder (%)

Crystal

Fine crystal

Powdered

sugar

Lenght of square side of sieve mesh (mm)


Weibull sugar silo

Conditions of sugar storage in silos Sugar perfect dust off

uniform quality

moisture 0.03-0.05 %

temperature 20–25 %

ash 0.02 %

reducing compounds 0.01 %

Air relative humidity 50-60 %


small overpressure inside silo


Course of sorptive isotherms for crystals of various quality

1 – the lowest quality, 2 – the medium quality, 3 – the highest quality

Equilibrium

moisture of

sugar (%)

Relative moisture of air (%)


Types of sugar according Czech Food Law

Group Subgroup

Sugar extra crystals mixture of crystals

caster sugar mixture of smaller crystals or pulverized crystals

powder mixture of fine pulverized crystals

Sugar white crystals

caster sugar

powder

Sugar semi-white crystals

caster sugar

powder

Powdered sugar can include (max. 3 %) anti caking agent

Pressed cube sugar (cube, bridge, loaf)

Sugar with additives

Natural sugar bulk, granular, light yellow crystal, slightly sticky

Candys mixture of big crystals, yellow – brown color

Liquid products invert syrup

caramel


Physical and chemical requierements on sugar quality

according Czech Food Law

Sucrose Ash Invert sugar Moisture

Color in

solution

Extra-white

White

Semi-white

© P.Kadlec - Sugar 2015 1 -...

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