AvH XIX th Symposium Troubleshooting in sugar factories.


REIMS, 29th of MARCH 2012

Maison des Agriculteurs, Reims

Association Andrew Van Hook
2, rue Léon Patoux, F-51664 Reims Cedex 2, France







8: 45 – Opening of Symposium
Session I: Campaign balance and the treatment of failures and malfunctions Session Chairperson: Philippe REISER, CEDUS, Paris, France

9:00: – Balance and statistics of failures and production halts during the last 10 campaigns, Rémi AUBRY, SNFS, Paris, France

9:20 –Trouble shooting of crystallisation in batch vacuum pan boilers, Mohamed MATHLOUTHI, , Association AVH, Reims, France

9:40 – Troubleshooting problems in beet sugar factories, an overview, Jan Maarten de BRUIJN, AB Sugar, G.B.

10: 00 – Coffee break, Posters and exhibitors
Session II : Production of steam and Evaporation : specific conditions of sugar factories

Session chairperson: Dr. Jan Maarten de BRUIJN, AB Sugar, Peterborough, G.B.
11:00 – Special features of operating of a steam boiler in sugar factories – Comparison to the

production of steam in other food industries, Franco MANISCALCO, Nalco, Italy

11:30 Controlling of evaporation in sugar factory – prevention of colour formation, Wolfgang KLOSTERHALFEN et Martin BRUHNS, Pfeifer & angen, Allemagne

12:00 – Posters and exhibitors 13:00 – Lunch

Session III: Examples of troubleshooting in sugar processing
Session chairperson: Dr. Martin BRUHNS, Pfeifer & Langen, Elsdorf, Germany

15:00 – To get and apply accurate and real-time process information for troubleshooting and trouble prevention in the sugar house, Tim DIRINGER and Bjarne NIELSEN, Neltec, Denmark

15:30 – Troubleshooting of decolorizing and de-ionizing resins in sugar processing, François ROUSSET, Novasep, Saint Maurice de Beynost, France

16:00 – Using real-time image analysis to control crystallization workshop dysfunction Bertrand GAILLAC, ITECA SODACEI, Aix-en Provence, France

16.30 – Reducing color helps reducing sugar loss in refinery: process problems and adapted solutions, Emmanuel SARIR, CarboUA International, Beverly Hills, CA, USA

17:00 – Conclusion

Simultaneous translation



Paper # 1

Balance and statistics of failures and production halts during the last 10 campaigns



SNFS, Paris, France

The technical commission of SNFS gathers together for more than 50 years delegates representing the technical and industrial directions of the sugar companies, sugar factory directors and process engineers. Three times per year at key periods of the sugar year (beginning and end of campaign, and also during the inter-campaign), we meet to exchange about questions linked to process. The commission supervises the whole actions of the profession in the technical field: methods of analysis and control, environment issues… The increasing importances of environment issues (energy, greenhouse gas, water and effluents, chemicals …) lead to the creation of a “Commission for industrial processes and environment” starting from 2011.

The presentation at AVH Symposium was initially entitled “Balance and statistics of failures and production halts during the last 10 campaigns”. SNFS decided to change this presentation under two angles:

1 – On the time scale, we will reduce from 10 to 5 last campaigns
2 – On the angle of approach, we will focus on the continuity of functioning rather than halts and failures.

The main concern of the sugar companies during the campaign is to operate continuously, without any halt of the factories. A brief overview of the exchange at SNFS meetings of the Commission for industrial processes and environment is given to summarize this concern and illustrate the fruit of efforts carried out to achieve it.

The overall statistics speaks for itself: setting up the ratio of the average tonnage of beets to the maximum tonnage sliced in the factories, we obtain a clear image of the regularity of operation in French sugar factories during the campaign. Since 2001, and this is the only reference for 10 years, this ratio is very close to 1.

The main causes of halts and unwanted events during the campaign are mentioned in the methodical order of control of the processes: equipment (machines), product (raw material), competence (manpower), organization (methods) and operation conditions (environment).


Paper # 2

Troubleshooting of crystallization in batch vacuum pan boilers



Professeur Emérite Association AVH

Conclusions of the assays on circulation in boilers performed by G.T.S. (Groupe Technique de Sucreries) in ten sugar factories and presented by R. Michel in 1963 GTS Congress, seem still relevant today. It was observed that the circulation of massecuite in batch vacuum pan boilers affects heat transfer coefficient, which in turn influences sugar quality by acting on sugar crystal growth rate, grain size distribution, crystal yield and massecuite exhaustion.

On the other hand, a study carried out at LSU, Baton Rouge under the direction of Peter Rein, using fluid dynamics computation and comparing different types of batch vacuum pan boilers was published in 2004 (P. Rein, L.F. Echeverri and S. Acharya, ASSCT, Vol., 2004). This study showed that the heat transfer coefficient is the real driving force of massecuite circulation in batch vacuum pan boilers. The mechanism of circulation was found complex depending on viscosity, fluid flowing regime, vapor pressure and vacuum. An estimation of the circulation showed the effect of batch pan geometry and other factors like syrup feeding conditions.

Massecuite circulation in batch vacuum pan boilers seems to be a decisive factor as regards the performances of the apparatus. The type of pan and agitation affect circulation and heat transfer coefficient. Feeding of syrup plays a major role since the evaporation of water governs the natural virculation and the position of feed pipes should not be in the central tube where it might slow down the circulation. Sugar quality (grain size, conglomerates, fines, ash, coloration) is affected by massecuite circulation. Batch vacuum pan boilers were found more adapted to high purity strikes.


Paper # 3

Troubleshooting in beet sugar factories: an overview


Jan Maarten de Bruijn

AB Sugar, Group Technology, UK

Though the need of troubleshooting seems to occur less frequent in today’s well controlled beet sugar factories, we shouldn’t forget that many process control parameters and set points are related to underlying chemical processes. A proper understanding and capture of the science behind the sugar process is invaluable to secure and support both the current and future operations in our beet factories. This paper presents an overview of the main troubleshooting parameters and further details about likely causes and possible control measures.

Examples are given of typical sugar extraction issues throughout processing, the origin of juice colour and ways to limit colour formation, as well as of lime salts, their relation to juice alkalinity and how this alkalinity can be influenced in processing. For troubleshooting of these ‘sugar technology’ related processing problems it is usually sufficient to focus on the following control parameters: juice pH and alkalinity, temperature and retention time. And then it is ‘just’ a matter of applying the science to the process!


Paper # 4

Special features of operating of a steam boiler in sugar factories – Comparison to the production of steam in other food industries


Franco Maniscalco

Nalco Service EMEA

In most of Sugar Mill, 100 – 200 T/h of superheated steam are produced at 40 Bars, in some case up to 65 – 75 bar. Most of the steam is used to produce electrical power in powerhouse. The low-pressure steam from the turbines is almost entirely used to operate the first effects of the evaporators.The steam from the intermediates effects is used by Almost all other units such as process Heaters, Diffusers, Sugar-end. Sometime a little amount of steam is used for the final wash of the sugar in the centrifuges.

Some main features makes such a steam station, absolutely different from the boilers operating in most of the food industries because of:

  • Quality of feed water
  • a long break between one beet-processing period and the next
  • Incidental condensate contamination by entrainment of syrup (Sugar Shots).
    Instead of high purity water (demineralised) process condensate, is the main source of boiler feed water. Process condensate, being contaminated by Volatile Organic Compounds (VOC) shows a high foaming tendency.
    As consequence, the damaging of the super-heater and the formation of deposits on the turbines are possible events in the steam/power house of sugar factories. This phenomenon, which is due to alkaline salt deposits carried by drops of boiler water, is a source of additional, significant costs. (Replacement of damaged components, production slowdown and even shutdown of the factory)
    The beet-processing period lasts 2 to 4 months, depending on sugar beet availability and weather conditions. It’s followed by a long intercampaign period, when boilers are shut down.
    It seems obvious that the corrosion processes find their best condition just during the inactivity period, since:
    • Extended areas of Boiler surfaces and steam/condensate network are usually exposed to the attack of diffused corrosion.
    • the bottom of the drum and the horizontal section of pipes, may be subject to localized corrosion under-deposit. In fact, the deposits act as a trap for the drops of moisture that could be condensate under cooling conditions.
      Occasionally sugar enters the condensate system (sugar shots) and returns to the boiler, it depresses the pH of the boiler water to levels that can cause corrosion within the system. High concentrations of sugar and other dissolved solids entering the boiler can be laid down as scale or caramelized on the tubes. It may even shut down the plant manufacturing process.


Paper # 5

Controlling Evaporation in a Sugar Factory – Prevention of Colour Formation


Wolfgang Klosterhalfen, Martin Bruhns

Pfeifer & Langen, Elsdorf, Germany

Formation of colour in in sugar factory evaporators depends on the chemical stability of juice, on the residence time and on the temperatures. The colour formation reactions and the important and operational chemical parameters are described. The design of the evaporators determines the residence time distribution and also the possibility of settlement of the juice droplets. By use of an example of a factory evaporator station having a high colour increase, the procedure to identify the reasons for colour formation is discussed. Advice on good practice of operation of tube and plate falling film evaporators will be given.


Paper # 6

To get and apply accurate andreal-time process

information for troubleshooting and trouble prevention in the sugar house


Tim Diringer and Bjarne Christian Nielsen

Neltec Denmark

Troubleshooting is the logical, systematic search for the origin of a problem, so that it can be solved. It contains the identification ofthe malfunction within a system, the solution to stop the malfunction, and the confirmation that the process or product quality has been restored. To quickly identify the problems within the sugar house and to solve them, the operators need a tool to observe the quality of the sugar and to react in a timely way to solve the problems. The Neltec ColourQ real-time colour measurement instrument for crystal sugar has been designed to monitor the sugar quality and to give the operators an easy understanding of any malfunction in the process, when the sugar quality is not within specifications.

The accuracy of the measurement allows the factory to run the process in the most efficient and economic way to reach the quality targets without the need for a large safety margin.
This paper describes the importance of troubleshooting and trouble prevention to avoid unacceptable deviations from good sugar quality. It also gives a stepwise description of the optimisation of the centrifugation process from the single machine to a complete control of the spray water dosing.


Paper # 7

Troubleshooting of ion-exchange systems in sugar production


François ROUSSET

Novasep, Saint Maurice de Beynost, France

Ion-exchange systems have now been used for several decades in sugar production, for such applications as thin juice softening in the beet sugar factories, or syrup decolorization in cane sugar refineries. Most difficulties in their operation can be addressed and avoided by suitable design parameters and proper insertion within the sugar production process.

Specific troubleshooting related to ion-exchange resins lifetime and maintenance are also addressed. Presentation includes real case studies about most frequent problems found during commissioning or long term operation, and corresponding solutions.
Maintaining trouble-free operation and high reliability of ion-exchange systems is now becoming current good practise in sugar production, just like other parts of the process.


Paper # 8

Using real-time image analysis to control crystallization workshop dysfunction


Bertrand GAILLAC

ITECA SODACEI Aix-en-Provence, France

ITECA SODACEI is a company specialized in on-line analysis and has developed since 2004 the production control by image analysis. The systems developed are used at 2 levels in the crystallization woekshop:

  1. –  First strike boiling to guarantee a correct crystallization
  2. –  At the centrifugal discharge to alert and correction in case of dysfunction
    Image analysis is a very useful tool in crystallization because it allows permanent observation of pan boiling. After footing, the quality of preceding pan washing can be controlled. Pan microscope obviously allows the control of seeding, one of the most important steps in crystallization process. During this step, the growth of crystals is continuously analyzed and an alarm is auctioned in case of dysfunction.
    The pan man has at his disposal the image of each strike in the control room and each batch is recorded and stored on the computer. Therefore, traceability is complete. Using image analysis allows informing the pan man in case the grain size is not conform to target. Many developments are currently carried on to permit following the growth of crystals during the whole duration of boiling and also to analyze massecuite color.
    The second place which proves to be strategic in the crystallization workshop is the sugar discharge at centrifugals. Image analysis brings here an appreciable added value as compared to a simple colorimeter. It appears, indeed, essential that a smart running of production needs to have information only provided by video and image analysis. The measurement of color accurately provided by Colobserver is one element of the numerous pieces of information reported to production supervisor. The possibility of displaying in real-time product image and to analyze it allows detection of dysfunction especially at the level of centrifugals by detecting spots of brown sugar. The size, shape and density of the spots on the image give important indications on the cause of the problem.
    A great advancement was achieved in the introduction of image analysis at this stage of sugar production by assuring the traceability not only by data in the form of digits and graphs but also by recording sequences of video of the observed problems, which allows an accurate analysis à posteriori, and to understand the nature of the problem.
    The sugar industrials who have shifted from classical system to a digital video technology have been immediately convinced by the validity of the measurement, the flexibility brought by these new systems in running the production and the total fitting with their needs.


Paper # 9

Reducing color helps reducing sugar loss in refinery: process problems and adapted solutions


Emmanuel SARIR

CarboUA International Beverly Hills, CA, USA

This paper reviews the use of Patent Pending High Performance Adsorbents Products in sugar refineries in order to achieve enhanced daily production, process efficiency, filterability improvement for carbonation refineries and savings on energy sources. Different process and technologies for sugar purification and its impact on sugar recovery will be reviewed and discussed. Enhancements in carbonatation and phosphatation clarification, as well as further enhancements with 2-stage purification methods to by-pass unit operations such as granular activated carbon or ion-exchange resin will be reported. The benefits will be presented based on (1) Improved final liquor colors/better refined quality (2) Improved daily throughput of sugar solids (3) Improved conversion rates of refined sugar per ton of raw sugar melt (4) Reduction in the amount of recycled (double-processed) recovery sugars and (5) Reduction in energy consumption per ton of sugar produced. The paper also includes graphical reports and schematic diagrams for showing point of product addition and general refinery flow.


Poster # 1


ICT Prague, Department of Carbohydrate Chemistry and Technology, Technicka 5, 166 28 Prague 6, Czech Republic; e-mail: ;

The aim of C sugar (after product) operation in a sugar factory is a production of high quality C sugar for effective follow-up refining, minimizing sugar in molasses together with low energy consumption. The C sugar operation involves vacuum evaporating crystallization of C massecuite, desugarizing during retention time in cooling crystallizers, centrifugation to separate molasses from C sugar and following affination of C sugar.

To optimize the course of cooling crystallization, a new static model was developed. The model involves balance equations for a horizontal crystallizer or for a part of vertical crystallizer of C-sugar operation and takes in account the balance of the sucrose ratio in liquid and solid phase. An addition of mixing media, such as syrup or water, into the crystallizer has been also considered.

The input parameters of this model are:

  • coefficients m, b from the Polish test to determine coefficient of supersaturation,
  • temperatures measured in individual stages of cooling crystallization including the
    outlet temperature,
  • dry substance contents and purities of massecuites and mother liquors in individual
    crystallizers (Sjreal, Qjreal), 
  • temperatures, purities and dry substance contents of added media (syrup, water), their
    possible inputs into crystallization stages,
  • average length of crystals entering into the C sugar operation to determine specific
    surface area,
  • weight contents of individual crystallizers.
    The model was verified practically in three Czech sugar factories.



With the kind contribution of


Centre d’études et de documentation du sucre
23 Avenue d’Iéna, 75116 Paris –


Green Chemicals, 7 Rue de Sterpigny, 6673 Gouvy, Belgium



BMA . Braunschweigische Maschinenbauanstalt AG . Am Alten Bahnhof5.38122Braunschweig.Germany www.bma-de.com


ITECA SOCADEI SAS www.iteca.fr
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proMtec Theisen GmbH Pforzheimer Straße 162 76275 Ettlingen, Germany




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