Conversion of All VHP Refinery Molasses into Value Added Brown Sugar
Dr. Jeffrey LeBlanc, Jeffrey Lancon & Dr. Chung Chi Chou
www.esugartech.com
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Cane Sugar Handbook, 12th edition, John Wiley & Son Inc,
Handbook of Sugar Refining, 1st edition, John Wiley & Son Inc,
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• High yield, very high purity (VHP) refineries• Organic sugar production• Value-added product introduction• Productivity improvement projects
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Company Objectives
Discuss four alternative processes for upgrading refinery molasses to value-added brown sugar• Areado process• Muscovado process• Micro-crystallization process• Improved Areado process
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Talk Objective
• There are many VHP refineries annexed to raw sugar mills or factories with #2/#3/#4 molasses and syrup recycled back to the mill for further processing to recover additional sugar during the crop seasons.
• However, during the “off crop” season, additional boiling cycles to #4/#5/#6 molasses is very inefficient due to extreme high viscosity.
• This results in low sugar yield and high energy cost
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Problem Statement: Molasses Sugar Losses
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Material and Color Balance on Syrup
750 ICU Raw Sugar
Phosphatation
Filter Press with Carbon
Evaporator
White Boiling #1
Centrifuge #1
100 lbs 99.5 purity
100 lbs 99.5 purity415 ICU
100 lbs 99.5 purity200 ICU
46.0 lbs 98.9 purity
White Boiling #2
Centrifuge #2
White Boiling #3
Centrifuge #3
22.1 lbs 97.6 purity
White Boiling #4
11.0 lbs 95.9 purity
Centrifuge #4
5.74 lbs 92.7 purity
White Boiling #5
Centrifuge #53.10 lbs 87.8 purity
White Boiling #6
Centrifuge #6
White Boiling #7
Centrifuge #7
1.80 lbs 81.4 purity
Molasses1.13 lbs 73.6 purity
Refined Sugar
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Material and Color Balance on Sugar
Units Incoming Syrup Color
(ICU)
Units Outgoing Purity (%)
Outgoing Color (ICU)
White Boiling #1 200 Centrifuge #1 99.92 10
White Boiling #2 455 Centrifuge #2 99.90 34
White Boiling #3 955 Centrifuge #3 99.88 100
White Boiling #4 2100 Centrifuge #4 99.86 263
White Boiling #5 4250 Centrifuge #5 99.84 640
White Boiling #6 - Centrifuge #6 99.81 -
White Boiling #7 - Centrifuge #7 99.76 -
• Convert the massecuite of molasses from #4 to MolasSugar by spontaneous crystallization
• Conventional VHP refinery sugar yield of 96.5-97.5% would increase to a new high of 98.5-99.5% by introduction of value added sugar products via fully utilization of “final molasses” and reduce energy consumption over traditional refinery schemes.
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Proposed Solution
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Proposed Solution750 ICU Raw Sugar
Phosphatation
Filter Press with Carbon
Evaporator
White Boiling #1
Centrifuge #1
100 lbs 99.5 purity
100 lbs 99.5 purity415 ICU
100 lbs 99.5 purity200 ICU
White Boiling #2
Centrifuge #2
White Boiling #3
Centrifuge #3
White Boiling #4
Centrifuge #4 Into Value-Added Brown Sugar!
• Introducing MolasSugar products• Process descriptions
– Areado– Muscavado– Microcrystalline sugar
• New and improved process• Conclusions
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Outline
• Value-added brown sugars with desirable flavors and textures
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MolasSugar
Purity Color Moisture
Muscovado 90 – 92 % 8,000 - 10,000 1.2 -1.5 %
Areado 96.5 – 97.5 % 3000 2.5%
Micro-crystalline 94 - 96 % 1,500 – 2,000 0.9 %
http://www.vidaativa.pt https://www.gourmetsleuth.com
• Global production of ~12.5 million tons• Demand for good quality muscovado is high
(particularly in Korea, Japan, France, and Germany)
• Good quality muscovado has traditionally been priced at around twice the retail price of refined white sugar
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Muscovado Sugar
Muscovado sugar has several uses;1) As sweetener or confectionery and is best for brewed coffee, milk, cereals, chocolates and juices; 2) For animal feeds, food and beverages and pharmaceutical products;
3) Production of plasticizers, plastics, elastomers and detergents.
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Muscovado Sugar
Alter Eco distributes their muscovado to cosmetics companies that produce natural body scrub. It is said that muscovadoadds moisture to the body scrub while providing exfoliating properties.
Characteristic molasses quality for brown sugar production,
For molassugar production, final molasses should meet the following additional conditions, • Massecuite purity should be at least 88 wt. %• Inverted sugars in massecuite should be <7% • Massecuite temperature should be over 245°F and • Massecuite should be at least 94 brix
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Molasses Quality
Purity Operation
Muscovado 92 – 94 % Batch
Areado 94 – 95 % Batch
Micro-crystalline 95 – 97% Continuous
New Process > 88 % Batch
1. Mixture of liquor and syrup is crystallized in a vacuum pan by spontaneous crystallization
2. Massecuite is heated and discharged into a mixer with vacuum
3. Massecuite is agitated under vacuum, water is further evaporate, the massecuite temperature drops and further crystallization occur
4. Crystallization releases heat and begins the transformation of the remaining syrup in the massecuite
5. Finally, the sugar is cooled, dried and sieved for packaging
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Areado Process
sucropedia
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Areado Operation• The mass and energy balance are used to determine the working
conditions in the areadores. • The mass and energy balance for the evaporation of could be
written as,𝐻𝐻𝑀𝑀 = 𝐻𝐻𝑆𝑆 + 𝐻𝐻𝑉𝑉 + 𝑞𝑞𝑚𝑚𝑀𝑀 = 𝑚𝑚𝑆𝑆 + 𝑚𝑚𝑉𝑉
• The working conditions determine areado sugar humidity for different purities, massecuite brix and massecuite temperature.
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Areado Operation
In this figure, the theoretical moisture of Areado sugar discharged from the mixer at 60°C and 99% purity is presented as a function of massecuite brix and temperature
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• Boil the feed, liquor and syrup in a 17 m3 calandria vacuum pan• The strike is started by feeding the mixture of liquor (10 to 11 m3,
75 Brix) and syrup (4 to 5 m3)• Remelt all the crystals that may remain in the pan, before starting
the boiling. This is done by breaking the vaccum and allowing the temperature to increase.
• After melting these crystals, the vacuum is increased, and, evaporation starts. Consequently, the sugar concentration increases and after 20 minutes the labile zone is reached.
• By spontaneous nucleation, crystallization starts which transforms the syrup into a heavy massecuite of small crystals
• The massecuite needs to be heated to 105-110 °C and 91-93 brix before being discharged into the Areadores
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Areado at RAR
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• Each areadores consists of one cylindrical closed vessel of 2.9 m in length by 1.5 m in diameter, with an internal paddle type agitator driven at 6 RPM by a 30 HP motor through a reduction gear.
• The rotating movement created by internal paddle agitator lifts the massecuite/sugar, increasing the exposed surface area and thus reaching high evaporation rates.
• The process of drying sugar takes on average 15 minutes
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Areado at RAR
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MolassesRaw Sugar
Affination
Decolorization
Crystallization
Recovery
Carbonatation
Areadores
Molasses
White Sugar Yellow Sugar
Raw Sugar
Melting
Decolorization
Crystallization
Clarification
Areadores
White Sugar Yellow Sugar
No Molasses
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• Juice extractors are composed of 2 or 3 cast iron roller mills driven by a 6 - 12 HP motor
• The cane juice is heated to 100°C - 105°C in cooking vats while being stirred
• To maximize the efficiency of the furnace, the cooking vats are arranged in series of three to four
• Each of cooking vat produces 110 lbs of muscovado every 3 hours
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Muscavado Process
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Muscovado Process
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• Important parameters to control in crystallization processes;– Rate of nucleation– Number nuclei formed – Rate of crystal growth – Thermal balance between heat of
crystallization and latent heat of evaporation
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Microcrystalline ProcessLiquor and Syrup
Concentrator
Crystallization
Liquid/Vapor Separator
Brown Sugar
Drier
Cooler
Screen
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• The rate of nucleation in a perfectly pure sugar solution can be approximated by the general equation of reaction kinetic,
𝑟𝑟 =1𝜈𝜈𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑 = 𝑘𝑘𝐶𝐶𝑛𝑛
• The rate of nucleation also depends on the impurities, ingredients added, degree of agitation, and the presence of seed crystals
• The faster the rate of nucleation, the greater the number of nuclei formed and the smaller the size of the final sugar crystal
• Van Weimarn’s equation relates the final crystal diameter d to the degree of supersaturation as
1𝑑𝑑
= 𝐾𝐾 ×𝑐𝑐𝐶𝐶𝑜𝑜
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Microcrystalline Process
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Microcrystalline Process
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Microcrystalline Process
Charles Graham, Louis Fonti Jr., Arnold Martinez 1972U.S. Patent 3,642,535
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• The evaporator is operated at a temperature in the range 120 – 130 oCwith or without vacuum, to produce concentrated syrup having a solids content of 91 to 97% by weight
• Concentrated syrup flows from the evaporator to the vapor-liquid separator where the vapor is removed by a barometric condenser and the syrup is fed to the nucleator/crystallizer
• The retention time of sugar in this unit ranges from 10 seconds to 120 seconds depending on the products desired
• Air is introduced into the nucleator/crystallizer to remove vapor released by the crystallization of material therein due to the heat of crystallization
• The sugar product in aggregate form, leaving the nucleator/crystallizer with a moisture content ranged from 0.5% to 2.5%, is fed to the dryer for further drying if needed
• The resulting dried aggregates are then supplied to a cooler where they are reduced in temperature to about room temperature
• The sugar aggregates are then milled and screened to meet product screen specifications
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Microcrystalline Process
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• Implements a high Torque mixer with an enlarged paddle - capacity increases and is able to process lower purity massecuite
• An improved Areado process (batch) – can crystallize massecuite of 88% purity
• Produces 3 grades of white sugar in addition to value-added brown sugar
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MolasSugar Process
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MolasSugar Process
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MolasSugar Process Control Loop Description
Method of Control
Equipment Requirement
Control I/O List Notes
Mixer Speed Control
Monitor Hz from VFD
VFD Drive with Hertz output
Ethernet
Mixer Drive On/Off
Monitor VFD power
VFD Drive “ “
Mixer Drive Torque overload
Monitor Amperage of VFD
VFD Drive “ “
Brix Monitor Amperage of Mixer Drive Motor
VFD Drive “ “ Indirect method of measuring Brix. Can also use time as a secondary measure.
Mixer’s Vacuum Pressure Monitoring
Pressure Transmitter
Pressure Transmitter (PT):
1 AI Includes separate back-up dial pressure indicator (PI)Pressure control would be part of eductor / condenser control
Entrainment Separator
Pressure Transmitter
Pressure Transmitter (PT)
1 AI Monitors cleanliness of Entrainment separator. High DP will trigger additional cleaning cycle
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MolasSugar Process Control Loop Description
Method of Control Equipment Requirement
Control I/O List Notes
Entrainment Separator Cleaning Valves-Open/Close control with Position Indication
Valve Position sensors/relays on valvePneumatic Actuator
Position sensors on Drain and Water supply valves (Open/Close)
4 DI
2 DO
Temperature –Monitor
Temperature Transmitter
Temperature Indicator Transmitter (TIT)
1 AI Not used as a control parameter, monitoring only
Mixer Outlet Valves –Open/Close control with Position Indication( 5 loops)
Valve Position sensors/relays on the stem of valvePneumatic Actuator
Position sensors on Mixer dump valve (Open/Close)
10 DI
5 DO
Each discharge valve will be actuated independently
Vacuum Break control
Valve Position sensors/relays on the stem of valvePneumatic Actuator
Position sensors on Vacuum Break valve (Open/Close)
2 DI
1 DO
Open close actuation of valve; no flow control.
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MolasSugar Process Control Loop Description
Method of Control Equipment Requirement
Control I/O List Notes
Cleanout cycle –multiple scenarios((2) Water Inlet valve, (2) Mixer Drain valves, (1) Steam valve, (1) Air valve)
Valve Position sensors/relays on the stem of valvePneumatic Actuator
Position sensors on Valves (Open/Close)
12 DI
6 DO
No flow measuring or flow control on water, steam, or air. Control via timers.
Hopper Discharge Valve
Valve Position sensors/relays on the stem of valvePneumatic Actuator
Position sensors on Valves (Open/Close)
2 DI
1 DO
No flow control. To be operated in conjunction with Cleanout cycle
Condenser / Eductor controls (water flow, Vacuum Pump on/off)
Pump On/Off Controls and status
Relays 2 DI2 DO
If some control of Vacuum is requested, a VFD can be installed on the cooling water pump.
Condenser / Eductor Water Temperature
Temperature Transmitter
Temperature Indicator Transmitter (TIT):
1 AI Not used as a control parameter, just monitoring
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For a VHP refinery with annual production of 200,000 tons sugar the additional revenue would be;
200,000 x 2% x $750/ton = $3 millions USD
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Implementation Benefits
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Conclusions• High demand for good quality brown sugar at a
premium price• Reviewed 3 existing technologies for value-added
brown sugar production from molasses• Introduced a modern MolasSugar process with
increased capacity and efficiency from existing processes
• A VHP refinery with the above process fully implemented would Produce no molasses and would Have significant reduction in energy consumption Increase in sugar yield by 2%
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References
1. C. C. Chou, Handbook of Sugar Refining, pp. 565-586.2. L. S. Bento, Proc. Sugar Ind Technol. Congr. New York,
1983, pp. 222-241.3. Dorr Tippen, Max Cohen, Freeman Bush U.S. Patent
3,194,682 19654. Marvin Miller, Max Cohen, Charles Graham U.S. Patent
3,365,331 19685. Charles Graham, Louis Fonti Jr., Arnold Martinez U.S.
Patent 3,642,535 1972 6. A. E. Nielsen, Kinetics of Precipitation, Pergamon Press,
Oxford, 1964
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Thank You!
Dr. Jeffrey LeBlancEmail:
[email protected]: www.esugartech.com
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If sugar is stored in humid conditions, water would be absorbed and a subsequent evaporation can cause caking of the sugar.
Experience shows that ratios of water to nonsucrose of less than 0.5 result in soft sugars have good storage characteristics. Furthermore, sugars with ratios in excess of 1.0 are prone to microbiological attack and fermentation.
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Muscovado Sugar
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Microcrystalline Process
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Microcrystalline Process
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From Evaporator
Syrup 1
Syrup 2
Syrup 3
1st Sugar
2nd Sugar
3rd Sugar
4th Sugar
1st m/c
2nd m/c
3rd m/c
4th m/c
Refined Sugar
Syrup 4
14.5 tons789 ICU
7.5 tons1559 ICU
4.1 tons2968 ICU
2.3 tons5471 ICU
24.4 tons406 ICU
10.8 tons23 ICU
12.2 tons828 ICU
5.2 tons37 ICU
6.3 tons1637 ICU
2.6 tons74 ICU
1.3 tons121 ICU
3.4 tons3117 ICU
20 tons40 ICU
Affination Syrup7.7 tons3722 ICU
Syrup 5
Syrup 6
Final Molasses
5th Sugar
6th Sugar
7th Sugar
5th m/c
6th m/c
7th m/c
Recovery sugar
3.0 tons10003 ICU
1.4 tons24165 ICU
0.7 tons52403 ICU
6.4 tons4095 ICU
3.4 tons129 ICU
2.6 tons11048 ICU
1.3 tons316 ICU
1.2 tons26581 ICU
0.5 tons759 ICU
5.2 tons236 ICU
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Process• A boiling scheme in which 40% of runoff syrup from the
previous strike requires only 1.2 tonnes of 3300 color syrup at 88% purity to produce 1 tonne of soft.
• Since this material is of a higher starting purity, lower material costs and less equipment are required for purification.
• A suitable starting materials can usually be prepared from a blend of 85% fourth runoff syrup and 15% B molasses, giving a yellow liquor of approxiamately 88 purity and 12000 ICU.
• When one compares the total amount of color that must be removed per tonne of soft sugar produced it is readily apparent that the back-boiling method reduces the processing requirement significantly.
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• Microcrystalline sugar• Free flowing brown sugar• Natural Sugar Granules
– From molasses, honey or maple syrups
• Amorphous (transformed) Sugar
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Brown Sugar
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Soft sugar can be boiled either as a single-grain or agglomerated-grain product. Single grain sugars are boiled in such a way as to give uniform single crystals between 180 and 240 microns. Single grain sugars rarely have a nonsucrosecontent much greater than 5%.
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Soft Sugar
Agglomerated style soft sugar is made up of very fine sugar crystals between 50 and 75 microns in size which have been allowed to fuse together in the pan to produce stable particles between 500 and 1000 microns. This produces a final product with a much great amount of surface area which can still be purged efficiently in a batch centrifugal to produce a soft sugar containing 8 to 11% nonsucrose. In addition, agglomerated sugar softs have an almost free flowing appearance and can readily be packaged in high-speed packaging equipment with relative ease.
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More on Agglomerated sugarThe agglomeration takes place immediately after the seed development phase when the pan is allowed to “sit down” with absolutely no agitation for an extended period. After this “sit down” period, the massecuite is tightened to the desired consistency and liquor feed begins at a slow rate until the desired quantity of liquor solids has been added. Syrup solids from the previous strike are added until the pan reaches its maximum capacity.
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Improved characteristics: anticaking, anti-separation, compressibility, emulsification, flowability, fondant quality, rate of dissolution and wettability.
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Microcrystalline/MolasSugar
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• Majority of the muscovado millers are producing typical muscovado, which cannot pass the 1.5% acceptable threshold for sediment content
• Furthermore, muscovado millers do not have any sugarcane raw materials during the “off crop” season
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Muscovado Sugar
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Brown Sugar
Nutrient Per 100 grams
Muscovado Refined SugarEnergy (Cal) 373 384Protein (g) 0.2 0Carbohydrates (g) 80.3 99.1Calcium (mg) 80.3 2Phosphorous (mg) 5.7 1Iron (mg) 2.48 0.2Magnesium (mg) 15.5 0Zinc (ppm) 3.01 0
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Muscovado Sugar
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Muscovado Sugar
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Muscovado Sugar
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Areado Sugar
Total sugars 96 - 97 %
Invert Sugars 0.4 – 0.6 %
Humidity 1.5 – 2.5 %
Ash 0.5 – 1.0 %
Colour IU 2,000 - 2,500
Typical analysis of Yellow Areado Sugar
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