The papers presented at the Meeting are listed below, linked to an abstract of the paper. In the future it will be possible to request a copy of each paper while reading the abstract.
#747 Analyzing Dextran in Sugar Industry: A Review of Dextran in the factory and a New AnalyticalTechnique
#748 Application of Aris Loop Chromatographic Process to Refinery Syrup Purification
#749 Influence of the Viscosity on the Film Evaporator as it arises on Vertical Plates
#750 Environment Policy and Practice in Saint Louis Sucre
#751 Al Khaleej Sugar - An Energy Efficient Refinery
#752 Symposium - no abstracts at this time
#753 Utilisation of Cane Sugar Refinery Carbonatation Sludge for Recycling and Boiler Flue Gas Desulphurisation
#754 Managing Acute & Persistent Crises beyond Operational Matters
#755 Sucrose Recovery from Molasses in the New Refinery
#756 Value Added Products from the Stillage of Ethanol-from-Molasses Plants
#757 New Developments of Centrifugals for High & Low Purity Massecuites
#758 Thirty Years of R&D in the Sugar Industry
#759 Explosive Decomposition of Low Raw Fillmass
#760 Discontinuous Sugar Centrifugal Drives Mechanical & Electrical system Confirguration for High End Variable Speed drives
#761 Protection Against Sugar Dust Explosions
#762 The Use of Reynolds Number NR as a Design Tool for Improving the Performance of Phosphatation Clarifiers
#763 Analyzing Dextran in the Sugar Industry
#764 Discontinuous Sugar Centrifugal Drives Mechanical & Electrical System Configuration for High End Variable Speed Drives
#765 Do we need a new Model for Sugar Plant Management Systems?
#766 Impurities removal from Raw Cane Sugar Remelts by Cross-Flow Filtration
#767 Centrifugal Washing Optimisation by Real Time Color Measurement
#768 Inorganics in Cane Sugar Process Refining By HPIC
#769 Conditions For Clear Liquor Storage at the Saint Louis Sucre Refinery in Marseilles
#747 ANALYZING DEXTRAN IN THE SUGAR INDUSTRY: A REVIEW OF DEXTRAN IN THE FACTORY AND A NEW ANALYTICAL TECHNIQUE
James S. Rauh, James A. Cuddihy, Jr. and Robert N. Falgout; Midland Research Laboratories, Inc., USA
The presence of Dextran in the factory, as a result of microbiological activity, is known to cause processing problems having financial impact beyond merely sucrose loss. The ability to measure the presence of Dextran may be a limiting factor in recognizing its true impact on factory operations. A new analytical test method using a monoclonal antibody procedure has recently been developed specifically for the sugar industry. The new test method eliminates the time consuming and labor intensive methods currently practiced for measuring haze formation. It also has the advantage of being able to test Dextran in juice, syrup, and molasses, as well as on the final sugar, while the currently used methods test only the final sugar. Using the test in the factory will allow operations to be adjusted accordingly to prevent slowdowns and reduce loss of sucrose. Comparison of test methods by procedure, precision and accuracy show that the monoclonal test procedure is clearly superior. The monoclonal antibody test method is more sensitive and the test can be conducted in 3-5 minutes, a significant improvement over all other methods. The antibody attaches to Dextran and produces a haze that is directly proportional to the amount of Dextran present. A specially designed nephelometer (turbidimeter) is used to measure the turbidity of the haze formed and the result may be expressed as PPM in solution or as PPM on solids. The test is also portable, allowing on-site testing at suspected trouble areas with immediate results.
#748 APPLICATION OF ARiS COUPLED LOOP CHROMATOGRAPHIC PROCESS TO REFINERY SYRUP PURIFICATION
M. Kearney, D. E. Rearick, and D. Costesso, Amalgamated Research Inc., USA
Although sucrose recovery by chromatographic processes has been increasingly applied in the sugarbeet industry since the first simulated moving bed (SMB) system was installed in l985, the application of this technology to sugarcane process streams has been rare. This is primarily due, in the case of cane molasses, to: lower molasses purity; higher invert level; and more severe problems with feed pretreatment. The application of SMB chromatographic separation to enrichment of refinery syrups, however, avoids the low purity and pretreatment problems of molasses and, in particular, Ari's Coupled Loop process can give a very efficient removal of invert. In conventional SMB processes, sucrose is treated as a retarded component relative to the salts and high molecular weight components of the feed material but invert, being lower in molecular weight, travels more slowly than sucrose and thus becomes difficult to eliminate from the sucrose fraction. In contrast, the conditions of the Coupled Loop process force sucrose to first behave like an excluded component and exit with the salt/high molecular weight fraction. This allows the efficient removal of a stream containing the invert and other low molecular weight components. A second set of parameters then operates on the sucrose-containing fraction to effect the rather easy separation of sucrose from salts and high molecular weight components. The entire process, consisting of two chromatographic loops, can be operated with resin and water requirements comparable to a conventional SMB operation.
In the pilot test to be discussed the Coupled Loop process was applied to a recovery house first boiling syrup (approximately 77 purity) to give a high-purity extract with excellent sucrose recovery.
#749 INFLUENCE OF THE VISCOSITY ON THE FIM EVAPORATION AS IT ARISES ON VERTICAL PLATES:
Examination of the Technical Glucose Solutions on a Falling Film Plate Evaporator
B. C. Schulze, L. G. Fleischer and W. Mauch, TU Berlin, Berlin Sugar Institute, Germany
Falling film evaporators allow to concentrate technical solutions with a high economical efficiency. Due to thin films on the heating surface, the driving force for heat and mass transfer, which are temperature and pressure difference, can be reduced.
The falling film plate evaporator is more and more accepted in the beet sugar industry, due to its low operating and maintenance costs and at the same time careful product handling. On the basis of the positive experiences, a pilot plant of a falling film plate evaporator was installed in the starch industry to determinate the thermodynamical behavior during the concentration of monosaccharide solutions.
To introduce an evaporating system into new production fields, the substances of the respective solutions have to be known. The dynamic viscosity is one of the main influences on the heat and mass transfer.
Thermodynamical result were compared to data obtained with technical tube bundle falling film evaporators. To understand the physical properties, the compound of the technical solutions as well as the dynamic viscosity at technical conditions concerning to the evaporation process were measured. Therefore, a high precision rotation rheometer as used. These results were compared to pure glucose solutions.
The molecular structure could be characterized by determination of the Huggins constant and the equilibrium of a- and B- D- glucose, by measuring the specific optical rotation.
The viscosity, that shows deviations from Newton fluids, can be expressed as a function of temperature, concentration and purity (considering the sucrose spectra), so the results are transferable to further technical monosaccharide solutions.
The measured properties allow to explain the dependence of heat and mass transfer on the film thickness and the shear rate on the film surface, which again is a function of the evaporation rate.
#750 ENVIRONMENT POLICY AND PRACTICE IN Saint Louis Sucre
Marie H. Chastan, Francois Verhaeghe, Denis Bouree, Saint Louis Sucre, France
The environmental management system at the Saint Louis Marseille Refinery is part of the global approach entitled Technique, Quality, Safety and Environment the aim of which is an improvement in our competitiveness.
The actions carried out within the context of environment are a follow up to the results obtained in the fields of quality and safety.
Thus, our environmental management system has been built with the same methodology as that used and experimented with for quality and safety. An important place has also been given to risk analysis and to the audit of our practices.
The organization of environmental documentation is designed to produce results and targets efficiency through simplification. We have also developed new and practical management tools and means of communication: IMAP (a reader and action oriented publishing method), environmental audits, training and crisis management.
The ever-increasing role of the media and the consequent need to manage and control our company communication have let us to formalize and introduce a crisis management organization, the principles and means of which will be presented in this paper.
The management of water represents a continually increasing cost and requires the implementation of a relevant environmental management system. The identification and subsequent separation of the various networks have produced a significant drop in the quantity of our waste (-29% between 1994 and 1997). The reduction in the COD discharged by the site, in response to legal requirements, together with the optimization of the overall effluent treatment cost, is currently being studied by means of a pilot study of the various available techniques.
The global approach should enable us to build an appropriate treatment station, which satisfies both technical and economic criteria, before the end of 1999.
#751 AL KHALEEJ SUGAR - AN ENERGY EFFICIENT REFINERY
Jamal Al Ghurair, G. C. Singh, AKS, Dubai, UAE
Recently a number of stand-alone refineries have been constructed close to their final markets in several locations around the world.
The Al Khaleej Sugar (AKS) refinery, located at the Jebel Ali port in Dubai, United Arab Emirates, was the first refinery to operate in the Middle East/Gulf market. Designed in 1992-93, and commissioned in 1995, the refinery has been operating at its design capacity of 100 tons melt/hour since November, 1997.
The refinery uses a conventional refining process, including carbonation and granular carbon decolourisation, but also has several innovative plant applications, including the use of continuous vertical pans for all white massecuite, and vapor bleeding from evaporators for pan heating.
Important design goals for the refinery included:
Finally, because of the high costs of fuel oil, electricity, and water, there was an overriding requirement that the refinery would be more energy-efficient than established refineries which operated at usage levels of about 3500 MJ/ton melt.
These goals have been large achieved, with refinery energy consumption while melting high purity raw sugar typically:
Boiler fuel 2188 MJ/ton melt
Carbon kiln fuel 30
Purchased Power 235
Total Energy used 2453 MJ/ton melt
This paper reviews the plant and process arrangements installed to achieve this results.
#752 SYMPOSIUM - No abstracts at this time
#753 UTILISATION OF CANE SUGAR REFINERY CARBONATATION SLUDGE FOR RECYCLING AND BOILER FLUE GAS DESULPHURISATION
L. Bento, A. Ferraz, F. Bártolo, J. Barretol, F. A. Rocha, M. Mota, RAR Refinarias, Portugal
Carbonatation is a robust chemical process used in cane sugar refineries for Affination liquors clarification. Calcium precipitates with CO2 forming sludge representing, in a cane sugar refinery, 1.7 ton per 100 ton of white sugar produced. In this study this sludge is treated by heating. The resulting product is used for boilers flue gases desulphurisation. Further heating increases the calcium oxide content on the product allowing its utilization in the Carbonatation process, mixed with fresh calcium hydroxide. It was observed in Laboratory tests that calcinated lime presents some advantages when recycled into Carbonatation process.
Boiler Flue gases from fossil-fuel combustion contain sulphur compounds, mainly sulphur dioxide. Environmental regulations are becoming more stringent and demand strict control of sulphur emissions to the atmosphere. On the other hand, sulphur present in the flue gases must be removed when these gases are used in Carbonatation of sugar solutions. In the sugar industry, flue gases for Carbonatation are currently scrubbed with water and a sodium carbonate solution. The produced wastewater with a high content of sulphuric acid and low pH is hard to deal with. To overcome the problem of treating this type of liquid effluents, a lab-scale facility was constructed that allowed the direct utilization of dried Carbonatation sludge, which removes completely SOx and partially NOx.
This process is potentially attractive for sugar industry, since it can save both process water and calcium oxide, simultaneously reducing the amount of wastewater. Results on this process are presented in this paper.
#754 MANAGING ACUTE & PERSISTENT CRISES BEYOND OPERATIONAL MATTERS
Johan Derijcker, Raffinerie Tirlemontoise, Belgium
Every crisis once was an issue. But then the issue got hurried along its way and the issue became a crisis -- either an acute or a persistent one. Incidents or issues became crises especially when the "Media" get hold of them - otherwise we are just faced with operational problems. And yet most crisis-plans concentrate too often on the operational side of a crisis, forgetting how to deal with the far more detrimental effects of Media-generated perceptions. In fact the essence of crisis-MIS-management is the tendency to turn a problematic situation into something far worse. That such tendencies still prevail is due to a lack of understanding of how the Media work and a lack of insight into consumer "risk-perceptions". The purpose of this paper is therefore to elucidate both these aspects, using actual case studies from our and related industries as an illustration in order to come to a well defined set of rules that will turn a crisis into an opportunity rather than a failure.
#755 SUCROSE RECOVERY FROM THE MOLASSES IN THE NEW REFINERY:
Comparison between crystallization and chromatography operations
S. Cartier, P. Bonnenfant, X. Lancrenon, F. Rousset; Applexion - S.C.I., France
In the New Cane Sugar Refinery that has been recently proposed by Applexion at the 1998 S.I.T. meeting, the raw sugar remelt is simply purified by microfiltration, decolorized and softened by ion-exchange, and finally crystallized in 2 strikes that provide white sugar and low purity mother liquor.
This New Refining Process is particularly attractive by eliminating Affination of raw sugar and the necessary recovery house.
The sucrose left in the low purity mother liquor can be recovered using two different processes:
- the either conventional crystallization in another 3 steps, producing final molasses and low purity sugars which are, after remelt, recycled back to the refinery process.
- or the chromatographic separation, generating a high sucrose purity extract recycled back to the process and a raffinate that constitutes the final molasses.
The objective of the present article is now to compare the performances of these two technologies in terms of sugar quality and yield, as well as capital and operating costs, for a 1000 t/day cane sugar refinery.
#756 VALUE ADDED PRODUCTS FROM THE STILLAGE OF ETHANOL-FROM-MOLASSES PLANTS
W. H. Kampen and Michael Saska, Audubon Sugar Institute, USA
Both cane and beet molasses are fermented into ethanol and carbon dioxide. The latter can be recovered in the liquid or solid (dry ice) form. By controlling certain fermentation parameters and selecting an appropriate yeast, increased levels of glycerine may be produced and recovered.
By treating factory juice with appropriate enzymes, phytic acid is converted into inositol and inorganic phosphate. The first can be recovered and the latter will improve the clarification. Naturally occurring compounds in molasses (e.g. betaine in beet and itaconic acid in cane) end up in the stillage and should also be recovered. A (partially) tested process with a high R.O.I. is proposed to recover these products.
#757 NEW DEVELOPMENTS OF CERTRIFUGALS FOR HIGH AND LOW PURITY MASSECUITES
Dietrich Bosse, Reinhold Hempelmann, BMA, Germany
Manufacturers of centrifugals are under a continued challenge to check and improve the design of their machines.
For continuous centrifugals of the K2000 series, a modular system was developed including several options such as magmatizing/melting facility, a syrup separator and/or a brake for the basket. A special steam-heated Turbo massecuite distributor serves to heat the massecuite to reduce its viscosity and thus increase the throughput. A novel tension balancing system absorbs the forces produced by the V-belt drive to reduce the loads acting on the bearings.
A new continuous centrifugal was developed especially for high purity massecuite. Its basket consists of two different-angle cones. A crystal rotor and a large housing minimize crystal breakage and residual moisture, the results achieved being comparable to those of batch centrifugals. The re-engineered batch centrifugals of the new B-series can be equipped with an innovative syrup separator which has fully come up to expectations in actual operation. Efficient separation of green and wash syrups provides for high purities in the wash syrup, allowing to increase the yield in each crystallization stage and positively influencing overall plant capacity.
Driving and control equipment were optimized by developing our own integrated control software and hardware.
#758 THIRTY YEARS OF RESEARCH IN THE SUGAR INDUSTRY
Chung Chi Chou, Mary An Godshall, Sugar Processing Research Institute, Inc., USA
It is said that scientists "rediscover the wheel" about every 20 years or so. While superficially this may seem so, it happens that within about 20 years, technology has usually made sufficient advances that new methods, techniques, and knowledge combine to make revisiting older subjects very profitable. These synergies can indeed result in advances useful for the sugar industry. At the same time that knowledge about older subjects is expanded by new technology, the advances in technology continue at an ever-increasing pace. Keeping up becomes ever more challenging.
This paper will summarize important research results relating to the sugar industry from major sugar research groups around the world during the last 30 years. It will explore the impact of selected discoveries from scientific, technical and commercial viewpoints. It will discuss how "rediscovering" or revisiting older information has been of benefit to the industry when combined with modern updating. The critical importance of maintaining information databases will be discussed as will the equally important subject of maintaining the flow of information to the industry as well as to younger scientists who will be responsible for future advances in the industry.
#759 EXPLOSIVE DECOMPOSITION OF LOW RAW FILLMASS
D. E. Rearick, J. Kusterer, Amalgamated Research Inc. and Amalgamated Sugar, USA
Spontaneous decomposition of molasses stored in tanks is well documented in the sugar industry. Such incidents have resulted in property damage (to tanks and surrounding equipment) and even loss of life. The general opinion is that such decompositions occur more frequently in cane molasses, due to its higher invert level, but spontaneous decomposition of lower invert materials, such as sugarbeet molasses, has definitely been reported.
Most of such reported incidents occur after long-term storage at moderately elevated temperatures but it should be realized that even relatively short periods (several hours) of severe overheating can lead to rapid thermal decomposition of concentrated sugar solutions and an accompanying pressure increase with possible disastrous results. Furthermore, such decomposition can occur in material much higher in purity and lower in invert than cane molasses. In February of 1995, the Nampa factory of Amalgamated Sugar Company experienced the explosive failure of a low raw fillmass distribution header that had been heated with high-temperature steam. This incident resulted in extensive property damage although, fortunately, no injuries. Details of the Nampa incident and pertinent literature references will be presented, as well as a general discussion of the factors necessary for the occurrence (and prevention) of such incidents.
#760 DISCONTINUOUS SUGAR CENTRIFUGE DRIVES MECHANICAL & ELECTRICAL SYSTEM CONFIGURATION FOR HIGH END VARIABLE SPEED DRIVES
M. Makina, B.W.S., Germany
In general we note a tendency for more and more large centrifuges. When we speak about larger centrifuges, we think often of the massecuite capacity by cycle and we forgot the massecuite throughput per hour.
Moreover, the size of the centrifuge is not always in conformity with the handling capacity of the factory and the existing periphery, i.e. sugar transport devices, dryer and others.
In order to fulfill the request of high throughput by considering the available peripheral devices, we developed, together with our partner, a new drive system for batch centrifuges. This drive system will be introduced in detail:
Sugar has power for magical effects - but power for electrical drives can only be done by innovation step by step. Where do we stay today - where do we want to go tomorrow (world wide Drive analysis).
#761 PROTECTION AGAINST SUGAR DUST EXPLOSIONS
Ake Harmanny, Stuvex Int., Belgium
After a short introduction into the phenomenon of dust explosions (including a demonstration with a sugar dust explosion) first of all the main explosion characteristics of sugar dust will be presented and discussed. Some information will be given on explosion statistics: how often do sugar dust explosions occur and in what kind of equipment.
With the help of several practical applications it will be presented how, in practice, sugar dust explosion hazards can be reduced to an acceptable safety level.
#762 THE USE OF REYNOLDS NUMBER (NR) AS A DESIGN TOOL FOR IMPROVING THE PERFORMANCE OF PHOSPHATATION CLARIFIERS
Thomas E. Craig, Lantic Sugar Limited, Canada
Refining of raw sugar requires a sequential series of separations to achieve the finished product. Amongst them is phosphatation clarification, which requires some specific conditions to achieve the best results, such as:
Deviations from any of these conditions will result in quality problems.
A critical part of the process is the injection of the polymer flocculant and the formation of secondary flocs. If the secondary flocs are being subjected to excessive shearing forces, caused by turbulence, poor performance will follow. By definition, Reynolds number is an index of the stability of turbulence in a moving fluid. (Ref. #l) Turbulence usually sets in at some critical value of NR.
Results collected at a number of refineries suggest there is a correlation between the Reynolds number (turbulence) in the piping from the reaction tank, to the clarifier. This can impact the performance of the clarifier.
This paper will summarize Lantic's experience along with data from other refineries using phosphatation clarification.
#763 ANALYZING DEXTRAN IN THE SUGAR INDUSTRY:
A Review of Dextran in the Factory and a New Analytical Technique
James S. Rauh, James A. Cuddihy, Jr., and Robert N. Falgout, Midland Research Laboratories, Inc., USA
See #747 for abstract of poster.
#764 DISCONTINUOUS SUGAR CENTRIFUGE DRIVES MECHANICAL & ELECTRICAL SYSTEM CONFIGURATION FOR HIGH END VARIABLE SPEED DRIVES
M. Makina, B.W.S., Germany
In general we note a tendency for more and more large centrifuges. When we speak about larger centrifuges, we think often of the massecuite capacity by cycle and we forgot the massecuite throughput per hour.
Moreover, the size of the centrifuge is not always in conformity with the handling capacity of the factory and the existing periphery, i.e. sugar transport devices, dryer and others.
In order to fulfill the request of high throughput by considering the available peripheral devices, we developed, together with our partner, a new drive system for batch centrifuges. This drive system will be introduced in detail:
Sugar has power for magical effects - but power for electrical drives can only be done by innovation step by step. Where do we stay today - where do we want to go tomorrow (world wide Drive analysis).
#765 DO WE NEED A NEW MODEL FOR SUGAR PLANT MANAGEMENT SYSTEMS?
Alberto Damasio, Orsi Automazione, Italy
Process Control and Production Management are often identified as the MAKE-function in the supply Chain model (Source-Make-Deliver)
Very recently AMR Research of Boston (USA) introduced the REPAC model, which organizes the various activities of the MAKE-function in five fundamental areas: Ready, Execute, Process, Analyze and Coordinate.
A modern Automation and Management integrated architecture for sugar companies should provide:
Moreover a pure three tier architecture (Data Servers, Application Servers, Local/Remote Clients) exploiting the Microsoft DNA (Distributed internet Architecture) framework is today needed, to permit encapsulation and geographic distribution of any best-in-class application module in the enlarged sugar enterprise (offices, plant, silos, beet/cane providers, sugar brokers, etc.).
CUBE, the ORSI Open Control System, has been developed in a modular and open architecture that allows the implementation of a REPAC-model of the process, fully integrating into a seamless and complete solutions every existing and/or new "automation island".
#766 IMPURITIES REMOVAL FROM RAW CANE SUGAR REMELTS BY CROSS-FLOW FILTRATION
M. Decloux, L. Tatoud, A. Mersad, Institute National de Recherche Agronomique, Food Eng. Dep., France
The interest on membrane filtration processes increased in the sugar industry these last ten years, especially with the development of the mineral membrane on the commercial market. In the sugar industry, two of the main interests of the membrane processes are the clarification and the color removal. Since 1987 we studied at ENSIA the interest of microfiltration to clarify raw cane sugar remelts. Then the research was extended to the ultrafiltration area as the decoloration rates were too low with microfiltration membranes. The efficiency of the filtration were mainly evaluated from the color and turbidity analysis of permeate and retentate and the permeate flux value after two hours of filtration with total recycling of the permeate in the filtration loop as usually done in the laboratories.
It appeared that it was necessary to extend the characterization of the sugar remelts to molecules suspected to be the main fouling ones. Thanks to an association with Louis Bento from the RAR refinery, the reducing sugar, dextranes and factor I.V. were evaluated.
In addition the characterization of the membrane efficiency with total permeate recycling in the filtration loop was not significant for an industrial extrapolation. It was necessary to test the influence of the concentration in the retentate of the molecules retained by the membrane. This parameter may be evaluated increasing the volumetric reducing factor (VRF) which is the ratio of feed volume with the final retentate volume. But to test significant VRF with a laboratory pilot (small membrane area) without interfering with the influence of the time, it is essential to minimize the death volume (final retentate volume) of the pilot. After modification of the ENSIA's filtration unit trials with increasing of the volumetric reducing factor were performed.
The objective of the presentation is to underline the influence of the membrane weight cut off and the VRF on the impurities removal ratios of raw cane sugar remelts.
#767 CENTRIFUGAL WASHING OPTIMIZATION BY REAL-TIME COLOUR MEASUREMENT
Bjarne Chr. Nielsen Neltec, Bevtoft, Denmark, Ronan Malgoyre, Francois Verhaeghe, Saint Louis Sucre, Marseille, France
Removal of color is the main purpose of the refining process. The color measurements from the laboratory are not available until the sugar has reached the silo so the control of the process is based on historical values and statistical process control instead of latest facts.
Automatic real-time color measurement has been tested on wet sugar from second strike centrifugals and compared with the laboratory measurement. The test has focused on the accuracy of the methods and on the influence from real-time measurements on the process control. A special investigation was made to reduce the loss of sugar due to unnecessary melting in the centrifugals.
#768 INORGANICS IN SUGAR PROCESS REFINING BY HPIC - A CHEMOMETRIC ANALYSIS OF DATA
Silva Pereira, RAR Refinarias et al. Department of Quimica - University of Aveiro, Portugal
In this work the authors pretend:
The data of inorganic compositions were obtained by ionic chromatography analysis on respective samples.
#769 CONDITIONS FOR CLEAR LIQUOR STORAGE AT THE SAINT LOUIS SUCRE REFINERY IN MARSEILLES
Sibylle Farine1, Ronan Malgoyre2, Stephanie Estoupan1, Antoine Puigserver1, and Anne Ferjancic-Biagini1, (1) Laboratoire de Biochimie et Biologie de la Nutrition, CNRS-UPRESA 6033, Faculte des Sciences et Techniques de Saint-Jerome, (2) Saint Louis Sucre, France
The purpose of this study was to determine the best conditions for clear liquor storage during the weekend in a cane sugar refinery in Marseilles (France). Samples were taken at weekly shut down of the refinery on early Saturday (0h-2h a.m.) and at the refinery start up on early Monday (5h-6h a.m.) in order to study clear liquor stability. An accurate carbohydrate analysis method, HPAE-PAD, was used to monitor the sucrose levels as well as those of the invert (D-glucose and D-fructose). Other conventional refinery measurements, Brix, color and pH were also investigated. Mannose, acetic- and lactic acid analyses using enzymatic kits were performed too, although these compounds did not appear to be relevant markers of the refinery liquor degradation during the period of time tested. The storage of a clear liquor under initial industrial conditions (73 Brix; 85 deg. C; pH 8.33; color 249 ICUMSA) was found to induce a drop in the pH value of 2.5 units, a two-fold increase in the color, about a ten-fold increase in the content of invert, and a subsequent 10% sucrose loss at the start up of the refinery on Monday morning. The resulting clear liquor could not therefore be used satisfactorily in the refinery process. Finally, the experimental conditions under which a 60m3 clear liquor tank should be stored during the weekend with no significant sucrose loss and invert production were established (70-75 deg. C; pH 7.0- 7.5). The process is reported and the subsequent overall improvement of the refinery production is discussed.