conversion of all vhp refinery molasses into value … of all vhp refinery...handbook of sugar...

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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Copyrights©esugartech.com All Rights ReservedAll Proceeds will be Donated to Wellbrook Foundation, Inc (Community Service since 1989; wellbrookfoundation.org)

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


46.0 lbs 98.9 purity

White Boiling #2

Centrifuge #2

White Boiling #3

Centrifuge #3


White Boiling #4


Centrifuge #4


White Boiling #5

Centrifuge #53.10 lbs 87.8 purity

White Boiling #6

Centrifuge #6

White Boiling #7

Centrifuge #7


Molasses1.13 lbs 73.6 purity

Refined Sugar

Presenter

Presentation Notes

Indicating the flow of syrup (or jet). Next slide discusses sugar product.

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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 #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

Presenter

Presentation Notes

This process of drying sugar via the “transformation” of a highly concentrated sugar syrup has been known for many years (i.e. rapid agitation of concentrated hot syrup under vacuum or convection)

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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



White Boiling #2

Centrifuge #2

White Boiling #3

Centrifuge #3

White Boiling #4

Centrifuge #4 Into Value-Added Brown Sugar!

Presenter

Presentation Notes

If a supersaturated sugar solution is heated to a high temperature and if a quick evaporation of water is provoked by strong agitation or by agitation under vacuum (heat is released to the vapors and supersaturation increases) initiating a spontaneous crystallization. This crystallization re;ease heat that evaporates more, increasing the supersaturation,, and further crystallization occurs with subsequent heat release and water evaporation. This phenomenon continues in a chain reaction until almost all the water is evaporated and the syrup layer is so thick that the crystallization almost stops. This process was called transformation. The final product consists in an agglomeration of sugar crystals with a syrup layer that is then dried and cooled.

• Introducing MolasSugar products• Process descriptions

– Areado– Muscavado– Microcrystalline sugar

• New and improved process• Conclusions

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Outline

Presenter

Presentation Notes

For boiled soft brown sugar, massecuite purity should run between 78 and 82%. For 50% yield on solids of a soft sugar containing 8% nonsucrose, the resulting runoff syrup will a have a purity of 68%.

• 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

Presenter

Presentation Notes

Strong molasses flavor, slightly coarser and stickier than most brown sugar

• 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.

Presenter

Presentation Notes

“Value Chain Analysis for Muscovado” Department of Agriculture Philippine Rural Development Project

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

Presenter

Presentation Notes


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

Presenter

Presentation Notes

The modern process makes use of vacuum pans and vacuum crystallizers, called areadores, and is used to make a yellow soft sugar. In order to complete massecuite transformation into a soft sugar, it is necessary to get a high sucrose crystallization rate and a high water evaporation rate in the areador. 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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Presenter

Presentation Notes

where HM is the total heat (sensible plus latent heat) of the massecuite, HS is the total heat of the sugar, HV is the total heat of vapor, q is the heat loss, mM is the mass of the massecuite, mS is the mass of sugar, and mV is the mass of vapor. Heat released from crystallization will provoke further evaporation and crystallization. At 60 °C the heat of crystallization of sucrose is 57.0 J/g and at 90 °C it is 107.6 J/g.

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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


• 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


Presenter

Presentation Notes

RAR Sugar Refinery, with a daily capacity of 500 tonnes, received raw cane sugar and produces white sugar and yellow Areado sugar. The production of Areado sugar represents 2.7% of the total production.

• 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


Presenter

Presentation Notes

Areado sugar process, using a simple equipment without great energy demand and having low maintenance requirements, is an atractive process to produce soft type sugars, although, to run the process, a great man-power is needed ( one man per areador )

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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


Presenter

Presentation Notes

Another advantage of yellow areado sugar production is the increase of refinery yield, by non-sugars inclusion in areador sugar. Therefore molasses production is reduced. Such a refinery, using high pol raw sugar, can reach a quantity of yellow areado sugar production in a way that excludes the necessity of residual molasses production. In this case, the refinery would only need a melting section, clarification, decolorization, white sugar crystallization and a~ areado sugar section. Affination and recovery sections would not be necessary. Investment and running costs of such a refinery would be less, compared with an only white sugar refinery, where the pleasant raw cane sugar flavors are sent to molasses for cattle feed compounds.

• 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


Presenter

Presentation Notes

(~0.75 m deep and 1.5 m in diameter) 150 - 200 kg per day per vat 750 - 1,200 kg per week per vat

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Muscovado Process


• 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


• 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


Presenter

Presentation Notes

where v is the number of nuclei formed per unit time and unit volume. where K is a constant and Co is the saturation at given temperature.

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Presenter

Presentation Notes

Crystallization from solution involves two phase change phenomena, namely nucleation and crystal growth. It is well known that, while crystal growth is related to supersaturation in a nearly linear manner, the nucleation rate is related to supersaturation in a non-linear fashion. The nature of the nonlinearity in nucleation kinetics is such that, the nucleation rate generally increases to a greater degree than the growth rate as the supersaturation is increased. Both nucleation and growth were described by Gibbs as discontinuous changes of phase which are large in degree but at least initially scall in extent in space. When one phase transforms to a more stable one, the atoms in some region of the first phase must become arranged in the characteristic configuration of the second. The formation of the resulting particle in a homogeneous fluid requires that an energy barrier be scaled. The mechanism of crystal growth from solution requires that solute be transported to the crystal surface and then oriented into the crystal lattice. Therefore, two consecutive steps are required, a diffusional process followed by a type of surface reaction step.

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Charles Graham, Louis Fonti Jr., Arnold Martinez 1972U.S. Patent 3,642,535


Presenter

Presentation Notes

Charles Graham, Louis Fonti Jr., Arnold Martinez 1972

• 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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• 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


Presenter

Presentation Notes

A PID for a modern spontaneous crystallization vessel generated at the request of a refinery with 5,000 ton/day of VPH raw sugar is shown below. The high torque mixer can be designed for 500 to 1,000 ton/day refinery capacity and would cost between $350,000-$450,000 dollars.

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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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Method of Control Equipment Requirement


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


Position sensors on Vacuum Break valve (Open/Close)

2 DI

1 DO

Open close actuation of valve; no flow control.


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Method of Control Equipment Requirement


Cleanout cycle –multiple scenarios((2) Water Inlet valve, (2) Mixer Drain valves, (1) Steam valve, (1) Air valve)


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


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


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


Presenter

Presentation Notes

(assuming $750/ton for the value-added product)

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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


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


Presenter

Presentation Notes


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Presenter

Presentation Notes

Dorr Tippen, Max Cohen, Freeman Bush 1965

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Presenter

Presentation Notes

Marvin Miller, Max Cohen, Charles Graham 1968

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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.


Presenter

Presentation Notes


• Microcrystalline sugar• Free flowing brown sugar• Natural Sugar Granules

– From molasses, honey or maple syrups

• Amorphous (transformed) Sugar

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Brown Sugar


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.


Improved characteristics: anticaking, anti-separation, compressibility, emulsification, flowability, fondant quality, rate of dissolution and wettability.

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Microcrystalline/MolasSugar


• 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


Presenter

Presentation Notes


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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


conversion of all vhp refinery molasses into value … of all vhp refinery...handbook of sugar...

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