Thin Juice Research Articles

THE EFFECT OF SULFITATION TREATMENT OF BEET-SUGAR PRODUCTION SEMI-PRODUCTS ON THE PROCESS OF INTENSIVELY COLORED HIGH MOLECULAR COMPOUNDS INHIBITION

Studies have been carried out to identify the effect of sulfitation treatment of sugar-beet processing semi-products on their color when it is carried out at one or several processing stages, as well as in its complete absence. At the first stage, the influence of the process of sulfitation treatment of the extractant and thin juice on the color of the thin juice and thick juice obtained from the thin juice by evaporation was studied. It was established that the sulfitation treatment of only the extractant provided a decrease in the color of the thick juice by 9.21%, while the sulfitation treatment of only thin juice – by 55.00%, and the sulfitation treatment of extractant and thin juice – by 58.16%. In addition, an increase in the purity of the thick juice by 0.45% due to the sulfitation treatment of the extractant and thin juice reduced the sucrose content in molasses by 0.11% and, consequently, reduced the overall loss of sugar in production. At the second stage, the effect of sulfitation treatment of a B+C remelt syrups with the use of sulfur dioxide and sodium bisulfite was studied. It was established that the amount of blocked aldehyde and ketone groups when thick juice was treated with sulfur dioxide was higher than when treated with sodium bisulfite due to the divalent anion SO 3 2– , and not the monovalent HSO 3– . At the third stage, under production conditions, the effect of sulfitation treatment of massecuite I on the boiling time and color of white sugar was studied. It was established that the average value of the color of white sugar in the presence of sulfitation treatment of massecuite I was 0.44 ICUMSA units, while without treatment – 0.50 ICUMSA units, i.e. under production conditions, the sulfitation treatment of massecuite A made it possible to reduce the color of the finished product – white sugar by 12.0%.

Thermostability of thin juice

The initial thin juice pH value usually changes during juice evaporation. As long as the pH value of the final thick juice differs maximal ±0.5 pH units, preferably ±0.2 pH units, from that of thin juice, the thin juice is considered thermostable. The observed change of the juice pH value depends on the ratio between dissolved ammonia and carbon dioxide in thin juice. During the juice concentration both volatile components will evaporate at which they have opposite effects with respect to the pH value change. Ammonia is dissolved as ammonium ion in the juice and leaves a proton in the juice upon evaporation, whereas carbon dioxide is dissolved mainly as bicarbonate and delivers alkali upon evaporation. This paper explains why a thermostable thin juice is crucial for the effectiveness of the following process steps evaporation and crystallization. Details about the origin of ammonia and carbon dioxide will be presented, as well as possible ways to control the thin juice thermostability by influencing the ammonia to carbon dioxide ratio.

The water fouling development in plate heat exchangers with plates of different corrugations geometry

The occurrence of fouling conditions in heat transfer equipment of industrial enterprises causes the change of process regimes and can lead to full blockage of heat transfer channels. The investigation of fouling dynamics in plate heat exchangers (PHEs) is observed. The transport and reaction type of fouling model is used for accounting for the fouling on the heat transfer surface. The mathematical model of PHEs with commercially produced plates is presented. The model accounts for the difference in pressure drop and heat transfer coefficients along with the heat carrier movement through the channel distinguishing the major corrugated field, the zones of flow distribution, ports and collector part, introducing the local hydraulic resistances for each zone. The PHE performance in fouling conditions for different plate corrugations geometry is analysed. The impact of the corrugations’ inclination angle to the vertical plate’s axis on fouling dynamics is analysed for the case when PHE is assembled with plates of non-uniform corrugations angles. The results of the case study, represented by modelling of PHE installed in a sugar factory for heating a thin juice coming to an evaporation station, are presented. The approach for fouling mitigation at PHE design through the optimisation of plate corrugation geometry is discussed. The economic analysis showed, that the purchase of additional plates for operating PHE allows for saving 220 kW of heat energy and ensures reliable operation during 120 d of the sugar campaign.

Improvement of the liquid-jet sulfitators construction to increase the efficiency of sulfitation treatment of sugar production liquids

The article discusses and analyzes the construction of liquid-jet sulfitators used in the beet sugar industry. The importance of sulfitation treatment in the sugar beet processing and raw cane sugar technology is noted and the main advantages of its use at various technological stages are given, namely, preparation of extractant used for diffusion sucrose extraction out of beet cossettes, thin juice processing, thick juice with B- and C-remelts processing, as well as raw cane sugar remelt processing. The advantages and disadvantages of liquid-jet sulfitators in comparison with other constructions are noted and criteria for their improvement are given. It has been noted that the created ejection, which sucks in the sulphitation gas into the contacting chamber, and the fact that the absorption of sulfur dioxide occurs on a larger surface than in other types of structures the main advantages of liquid-jet sulphitators. The main disadvantages are the short length of the contacting chamber, which is insufficient for ensuring complete absorption of sulfur dioxide, as well as instability of the generated ejection when the productivity changes. This determines the criteria given in the article for the improvement of liquid-jet sulfitators. The description of the developed construction of the sulphitator centrifugal-jet nozzle of sugar production liquids is given, which provides: the stability of the sulphitation gas supply in a wide range of plant productivity; stability of the hydroaerodynamic regime of the system «treated liquid – sulphitation gas» inside the sulphitator; sufficient contact time for complete dissolution in the treated liquid of the sulfur anhydride contained in the sulphitation gas. The advantages of the developed centrifugal-jet sulfitators in comparison with typical liquid-jet sulfitators are noted: ensuring the operation range of 50-120% of the nominal capacity (plant production capacity); significant reduction in the technical sulfur consumption for the sulphur anhydride production, which is used as a reagent for the sulfitation treatment of liquids in beet sugar processing; reduction of harmful emissions into the atmosphere due to 100 % sulfur anhydride dissolution in the treated liquid.

Principles of juice purification

The raw juice as obtained by juice extraction of sugar beet cossettes contains dissolved and insoluble impurities (nonsugars) which need to be removed as much as possible to enable a cost-effective production of the wanted quality of white crystal sugar. The most commonly used purification approach of beet raw juice is the so-called classical liming process. The aim and principles of the different successive process steps in juice purification will be outlined in this paper. The purification principles comprise several chemical-physical reactions of particular nonsugars in the juice which are initiated at first by the addition of milk of lime to the raw juice in preliming and main liming. Through injection of the carbon dioxide produced in the lime kiln in the 1st carbonatation calcium ions precipitate as calcium carbonate, which is then used as filter aid to remove by sedimentation and/or filtration the formed slurry. The remaining surplus of lime salts are finally removed in the 2nd carbonatation which after filtration results in a clear thin juice.

Operation of a six-effect evaporator station with a deficit in the vapour balance

During the operation of a six-effect evaporator station the vapour balance is subject of interfering incidents such as changing technological states of the process or surrounding conditions (ambient temperature e.g.) This article analyses and compares possible methods of managing the operation i.e. reaction to these incidents. In particular, methods of stabilizing the vapour balance by supplying water or thin juice to individual effects of the evaporator station and bypassing the vapours between effects are compared. The best way of reacting to the overload of the evaporator station seems to be the bypass of vapour from an effect of higher parameters to an effect of lower parameters. This method creates a much faster reaction of the evaporator station to excessive bleeding of vapour than supply of water or thin juice, which need to mix with the juice in the vessels. Feeding water to the thin juice tank or to one of the effects of the evaporator station to compensate excessive vapour consumption can be an acceptable solution in case of prolonged increase in vapour consumption from the evaporator station due to e.g. a significant decrease in ambient temperature.

Influence of exopolysaccharides on viscosity of sugar juices with low sucrose contents

The presence of dextran originating from frost-damaged or degraded beet is highly detrimental during beet sugar manufacture, because they cause difficulties in filtering the carbonatation juice. In this paper the impact of exopolysaccharides on the viscosity of low sucrose content juices including: raw juice, juice after the 1st filtration and thin juice were analyzed. Studies have shown that high molecular mass exopolysaccharides have a stronger effect on the juice viscosity than low molecular mass exopolysaccharides. However, the dynamic viscosity of technical sugar solutions (raw juice or thin juice) with exopolysaccharides at a content of up to 0.5 g/kg, is lower than the viscosity of pure sugar solutions having the same refractometric dry substance content (RDS).

EFFECT TO CROP ROTATION AND FERTILIZATION SYSTEM IN YIELD AND TECHNOLOGICAL QUALITY IN SUGAR BEET (BETA VULGARIS L.)

he quality of sugar beet roots is estimated by the concentrations of K, Na and ?-amino nitrogen in cell fluid since sucrose content in the cell vacuole is the result of a balance of other active osmotic compounds (K and Na ions). Along with the increasing dose of organomineral fertilizers, sugar losses in molasses increase, the thin juice purity decreases, and, accordingly, white sugar yield decreases. Therefore, the optimal dose of fertilizers within the organomineral fertilization system on the typical leached chernozem (in the zone of sufficient soil moisture) was 40 t/ha of cattle manure + N90P110K130, which provides sugar yield of 6.37, 6.32, and 6.48 t/ha. Analysis of sugar yield per hectare under the conditions of insufficient soil moisture shows the importance of the right decision on short crop rotation. Thus, the highest sugar yield (5.73 t/ha) was observed in the grain – grass – hoed crop rotation against the background of 25 t/ha of cattle manure + N90P120K90. However, increased fertilizer doses, 25 t/ha of cattle manure + N135P180K135, causes a reduction in sugar yield and is not efficient in terms of additional input

Comparative evaluation of sugar beet processing intermediates color using various treatment methods

The article presents the results of a study of the influence of raw juice obtaining methods, namely, using an extractant, acidified with sulfuric acid with the addition of a suspension of freshly prepared gypsum, and using an extractant, treated with sulfur dioxide, as well as subsequent treatment of obtained thin juices with sulfur dioxide before evaporation on the color of sugar beet processing intermediates. A brief description of methods to reduce intermediates color used in sugar industry–sulfitation, ion-exchange and active carbon treatment is given. The advantage of intermediates treatment with sulfur dioxide compared with treatment with ion exchange resins and activated carbon is theoretically justified. The methodology for setting up laboratory tests is given and substantiated. The color indicators of raw juices, thin juices and obtained thick juices are given. It was established that a single treatment of intermediates with sulfur dioxide at the stage of raw juice obtaining provides a decrease in thick juice color by 7.11 %, a single treatment before evaporation–by 29.70 %, and a double treatment at the stage of raw juice obtaining and before the evaporation station–by 38.37 %.

Lime salts: origin and control in beet processing

Lime salts in the thin juice obtained after juice purification is one of the most important chemical KPI’s (Key Performance Indicator) in beet processing. Too high lime salts content will significantly affect processing costs – particularly energy – due to scaling of heat exchange surfaces thus decreasing heat transfer. In addition, high lime salts are at the origin of turbidity and insoluble solids in white sugar. Therefore, it is of the utmost importance to understand the chemistry behind lime salts in beet processing in order to be able preventing too high lime salts contents in thin juice. This paper will explain the details of the chemistry behind the presence of lime salts. Further, a trouble-shooting guide is included to elucidate the different causes for high lime salts contents and how these causes can be identified, as well as the process measures to reduce the lime salts content in thin juice.

Comparison of evaporator stations with and without pre-evaporator

Two sugar factories with a processing capacity of 6000 t/d of beet and falling film type evaporators in all effects but differing in the lay-out of the evaporator station were compared. A five-effect station with serial juice flow from effect 1 to 5 was compared with a five-effect station, where the thin juice is fed into the 4th effect (pre-evaporator), and then after additional heating to the 1st effect. For the two sugar factories identical process parameters and identical technological equipment were assumed. It was found that the use of a pre-evaporator gives significant operating benefits to the operating of the evaporation station, which may support decision of its application despite the higher installation costs compared to the station without pre-evaporator.

Dextran-induced modifications of calcium carbonate particles precipitated during carbonatation

The effects of high and low molecular mass dextran (T2000 and T40) on the size and shape of particles precipitated during carbonatation and their correlation with filtration performances were key to this study. Varying contents of T2000 and T40 dextran in sugar solutions corresponding to DS contents of thin juice were investigated. For particle size and shape analysis, static image analysis and laser particle size analysis were used. Both methods, static image analysis and laser diffraction, revealed that the presence of T2000 and T40 dextran leads to a higher amount of large-sized particles at the expense of small-sized particles, indicating pronounced agglomeration. The additional evaluation of shape parameters (circularity, roundness, solidity) obtained from static image analysis indicates that the agglomeration is oriented in the absence and in the presence of lower T40 dextran levels. Besides, non-oriented agglomeration, resulting in more round agglomerates with smoother surfaces, was found for samples loaded with T2000 dextran and high T40 dextran levels. Only the latter samples have shown to negatively affect the filtration performance. Thus, in the presence of T2000 dextran and high T40 dextran levels, the filtration was hampered. This appears to be mainly caused by a tighter packing of more round calcium carbonate agglomerates in the porous structure of the filter cake.

Membrane Characterisation for Fractionated Dextran Analysis in Sugar Industry

The separation characteristics of two polyethersulfone membranes (molecular weight cut-off (MWCO) specification of 4 kDa and 10 kDa) for the retention of different dextran fractions (T2000, T40, T10) from aqueous solutions were systematically investigated, aiming at implementing them as a preparatory step for dextran analysis in sugar industry practice. Ultrafiltration is used to cause differences in optical rotation due to mechanical separation of dextran from aqueous solutions. The membrane separation performance was evaluated using polarimetry and size exclusion chromatography. It was found that the presence of sucrose leads to dramatically improved separation efficiencies for both membrane settings. Specific cut-off values for the separation of dextran from aqueous sucrose solutions have been determined, 10 kDa and 50 kDa for the membranes with a MWCO specification of 4 kDa and 10 kDa, respectively. The data indicate that the basic membrane setting (MWCO of 4 kDa) enables the complete separation and therefore the analytical quantification of the whole molecular mass spectrum relevant for sugar industry. The combination of both membranes, furthermore, indicates that it is suited for the differentiation between a high and a low molecular mass dextran fraction. The application of this new approach for the determination of dextran with varying molecular masses at various contents in synthetic thin juices as well as in real sugar beet raw juices indicates promising prospects.

Kinetička analiza alkoholne fermentacije među i nusproizvoda prerade šećerne repe u laboratorijskom bioreaktoru

Bioethanol production in batch culture by free Saccharomyces cerevisiae cells from intermediate and by-products of sugar beet processing was investigated. This research relays on the previously conducted experiments in the bioreactor of 1.5 L working volume where key fermentation parameters, including initial sugar concentration and fermentation time, were optimized. This study was performed to validate the applicability of obtained results in the enlarged scale i.e. in 10 L laboratory bioreactor. The main aim was to analyze the bioprocess time course by monitoring the yeast cell number and concentrations of sugar, amino nitrogen, total soluble salts,and ethanol. Also, the kinetic analysis of ethanol and yeast biomass formation as well as sugar consumption during fermentation of media based on raw juice, thin juice, thick juice,and molasses was performed.

Prediction of fouling tendency in PHE by data of on-site monitoring. Case study at sugar factory

The fouling deposition on heat transfer surfaces can have significant detrimental effect on heat recuperation and jeopardise the efficiency of energy usage, increasing fossil fuels consumption and harmful environmental effects. The data of plate heat exchanger (PHE) thermal performance monitoring in fouling conditions are presented. PHE is installed at sugar factory for preheating purified thin juice before evaporation. The character of deposits on plate heat transfer surface is examined by opening PHE after the tests. It reviled the scaling and particulate fouling mechanism. Mathematical model for prediction of fouling deposition development in time is proposed, which accounts for shear stress at the channel walls and surface temperature. The model parameters are determined according to industrial tests data. The ways of fouling mitigation in PHE are discussed using the model predictions. It is shown that fouling mitigation in PHE is possible by increasing wall shear stress at the same pressure drop in heat exchanger. It requires to eliminate additional pressure loss in connections and to optimize the number of plates and their arrangement adding some plates with higher corrugation angle. These recommendations are discussed and some are implemented at the factory conditions. That allowed increase the operation time between stops for PHE cleaning maintenance. The proposed model can be directly used for design and maintenance scheduling at the specific factory. It can also be used asa preliminary guidance for energy saving reconstructions in other sugar factories. But the direct model application requires data of fouling formation monitoring to identify its parameters for work with specific media streams prone to fouling.

Experimental Investigation of Nanofiltration Process for the Separation of Complex Sugar Mixtures Containing Mono- and Multivalent Salts

The energy consumption of sugar producing industry is enormous mainly due to the thermal energy demand of multi-stage evaporation. However, alternative processes have been studied to reduce the high operating cost. Membrane technology is a well-established process for water treatment. Reverse osmosis (RO) and nanofiltration (NF) have also been examined for the pre-concentration of clarified thin sugar juice to reduce the role of evaporation in the sugar production process. RO/NF can be used to remove water from the aqueous solution at a temperature below its boiling point and without phase change. It has a positive effect on the quality of the clarified thin sugar juice because sugar juice is degraded at high temperatures. The clarified thin sugar juice contains 15 °Brix (15 w%) of sugar and about 0.25 - 0.40 w% of the ionic compounds. In the present work the effect of the presence of monovalent and multivalent salts on the separation performance of a nanofiltration membrane during sugar concentration has been studied experimentally. The sugar rejection was not affected much by the salt concentration but the rejection of monovalent or multivalent ions was found to be highly dependent on the sugar concentration.

Investigation of corrosion resistance of steel used in beet sugar processing juices

In this study, corrosion behaviors of materials used in diffusion units and equipment used in juice clarification steps and tubes in evaporators at Ankara Sugar Factory were investigated in terms of juice production and juice clarification processes as well as juice medium at evaporation stages. The measurements have been performed by comparing steel types used in these units and alternative types of steels that can also be used during the study. For this purpose, pH and Brix (Bx, refractometric dry matter) values of raw juice, thin juice and juice taken from evaporator have been measured during 2009–2010, 2010–2011, and 2011–2012 campaign periods of Ankara Sugar Factory. In addition to these measurements, traditional weight loss and electrochemical tests such as Linear Polarization Resistance (LP), Tafel Extrapolation (TP), Electrochemical Impedance Spectroscopy (EIS) were performed to measure and compare the corrosion rate of the metals used in different juice mediums. The metals included in the study were AISI 316L, AISI 304L grade stainless steel, St 37.2 grade carbon steel and nickel-coated St 37.2. The highest and the lowest corrosion rates were recorded for raw juice and thin juice, respectively. St 37.2 steel had the fastest corrosion rate, whereas the stainless steel AISI 316L has the slowest corrosion rate. However, AISI 316L shows only slightly higher corrosion resistance compared to the corrosion resistance of AISI 304L in different juices. Therefore, AISI 304L steel, which is cheaper than AISI 316L, can be selected as a substation of St 37.2 steel.

Technological qualities of defoliated and topped sugar beet

It is well known that beet with crown tissue have a higher content of melassigenic nonsugar substances than correctly-topped beet. However, there is a lack of information on the impact of this change on processing. Hence, the objective of this study was to determine the effect of defoliated beet on the different processing steps. Laboratory-scale processing experiments were conducted with defoliated and manually-topped beet from five sites in 2010/11 to 2012/13. Beet brei, raw press juice and thin juice have been analyzed, the subsequent effects have been simulated with a specially developed model. The results show that the beet composition changes increasingly when including a larger proportion of the crown tissue. Consequently, cutting off the first millimeters of the top of the crown will remove the worst part of the beet. Defoliated beet have a poorer technological quality compared to topped beet with a significantly higher content of melassigenic compounds, in particular -aminoN and invert sugar, and a lower pol. sugar content, thus resulting in a lower purity. This effect is similar for all products, beet brei, raw press juice, and thin juice. In thin juice, the effective alkalinity is significantly reduced, while colour and lime salts’ content are increased. Because of the lower quality/purity of defoliated beet more beet will have to be processed to produce the same quantity of white sugar, so the processing campaign will become longer. In the simulation model a lower thick juice purity and a higher molasses purity have been assumed for defoliated beet, as based on juice analysis and technological expectations. The higher content of nonsugars will result in an increased mass flow through the sugar house which will negatively affect the molasses exhaustion. At the same white sugar production, the simulation model calculates higher costs for processing aids and energy, but on the other hand also higher revenues for the additional production of pellets and molasses when processing defoliated beet.

Modelling and prediction of bioethanol production from intermediates and byproduct of sugar beet processing using neural networks

The aim of this work was to model and predict the process of bioethanol production from intermediates and byproduct of sugar beet processing by applying artificial neural networks. Prediction of one substrate fermentation by neural networks had the same input variables (fermentation time and starting sugar content) and one output value (ethanol content, yeast cell number or sugar content). Results showed that a good prediction model could be obtained by networks with single hidden layer. The neural network configuration that gave the best prediction for raw or thin juice fermentation was one with 8 neurons in hidden layer for all observed outputs. On the other side, the optimal number of neurons in hidden layer was found to be 9 and 10 for thick juice and molasses, respectively. Further, all substrates data were merged, which led to introducing an additional input (substrate type) and defining all outputs optimal network architecture to 3-12-1. From the results the conclusion was that artificial neural networks are a good prediction tool for the selected network outputs. Also, these predictive capabilities allowed the application of the Garson's equation for estimating the contribution of selected process parameters on the defined outputs with satisfactory accuracy.

Experiences with FSB weak acid thin juice softening at the Suiker Unie Anklam sugar factory during the 2013 and 2014 campaigns

In 2013 the Fractal Shallow Bed Weak Acid Cation (FSB-WAC) softening system was installed at Suiker Unie Anklam. To evaluate the FSB system, a team from Cosun Food Technology Centre investigated the process during the start-up campaign in 2013. At the beginning results of the softening were good, but at the start up of a service run a pH value drop occurred and optimal softening started with a delay due to chemical kinetics. After 5 weeks of operation, performance went down. Calcium sulphate precipitated on the resin bed and beads started to clump, resulting in a poor softening performance and insufficient regeneration caused by preference streams in the resin bed. A result of the investigation was a list of recommendations for improving the FSB-WAC operation, which were discussed with factory staff and a supplier and led to a couple of modifications. In 2014 the decalcification system performed substantially better. The pH value drop at the beginning was much less and the softening started on the maximum level. At the end of the campaign beet processing was, during five weeks, seriously disturbed by deteriorated beets and juice quality declined rapidly. The FSB-WAC system survived these extreme conditions with stable performance but the hardness of soft juice was sometimes too high due to technical limitations and the priority to keep beet processing running.