© P.Kadlec - Sugar 2015 3
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
© P.Kadlec - Sugar 2015 4
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
© P.Kadlec - Sugar 2015 5
WORLD PRODUCTION AND CONSUMPTION OF
SUGAR
20 % FROM SUGAR BEET
production
consumption
(thousands t)
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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
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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
© P.Kadlec - Sugar 2015 9
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, …)
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BASIC ANALYTICAL TERMS
Dry substances S (%)
Sucrose P (%)
Nonsugars N = S - P
Purity Q = P/S . 100
Ash A (%)
Reducing substances, RL (%)
Invert sugar
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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
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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
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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
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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
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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
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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
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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
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Pulp
Pulp pressing dry matter 15-25 %, max. 30-35 %
effectivity of pressing depends on:
physical properties of cossettes
temperature 50-55 °C
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
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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
© P.Kadlec - Sugar 2015 20
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
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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)
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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 %
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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
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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
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Vapor
Noncondensable
gases
Condensate
Juice feed
O
d
v
o
d
š
ť
á
v
y
Juice outlet
Steam
Robert evaporator
splash head
tubes
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Scheme of evaporator station
Thin juice
S=15 %
Thick juice
S=65 %
to steam boiler plant hot condensate
to barometric
condenser
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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
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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
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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
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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
© P.Kadlec - Sugar 2015 31
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
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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
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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
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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
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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)
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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 %
temperature 20-22 °C
small overpressure inside silo
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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 (%)
© P.Kadlec - Sugar 2015 39
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
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