Increased profitability through product diversification and improved sugar quality.

The proposed simplified Integrated Sugar Production Process (ISPP) using membrane technology would allow the sugar industry to produce new product streams and higher quality mill sugar with increased sugar extraction efficiency. Membrane filtration technology has proven to be a technically sound process to increase sugar quality. However commercial viability has been uncertain partly because the benefits to crystallisation and sugar quality have not outweighed the increased processing cost. This simplified ISPP produces additional value-added liquid streams to make the membrane fractionation process more financially viable and improve the profitability of sugar manufacture. An experimental study used pilot scale membrane fractionation of clarified mill juice confirmed the technical feasibility of separating inorganic salt and antioxidant rich fractions from cane juice. The paper presents details on the compositions of the liquid streams along with their potential uses, values and challenges in getting these products out to market.

Increased profitability through product diversification and improved sugar quality.

The proposed simplified Integrated Sugar Production Process (ISPP) using membrane technology would allow the sugar industry to produce new product streams and higher quality mill sugar with increased sugar extraction efficiency. Membrane filtration technology has proven to be a technically sound process to increase sugar quality. However commercial viability has been uncertain partly because the benefits to crystallisation and sugar quality have not outweighed the increased processing cost. This simplified ISPP produces additional value-added liquid streams to make the membrane fractionation process more financially viable and improve the profitability of sugar manufacture. An experimental study used pilot scale membrane fractionation of clarified mill juice confirmed the technical feasibility of separating inorganic salt and antioxidant rich fractions from cane juice. The paper presents details on the compositions of the liquid streams along with their potential uses, values and challenges in getting these products out to market. This paper was presented at the 2010 Australian Society of Sugar Cane Technologists annual conference.

Membrane fractionation technologies for high quality mill sugar and value-added by products - an integrated sugar production process concept model.

Membrane filtration technology has been proven to be a technically sound process to improve the quality of clarified cane juice and subsequently to increase the productivity of crystallisation and the quality of sugar production. However, commercial applications have been hindered because the benefits to crystallisation and sugar quality have not outweighed the increased processing costs associated with membrane applications. An 'Integrated Sugar Production Process (ISPP) Concept Model' is proposed to recover more value from the non-sucrose streams generated by membrane processing. Pilot scale membrane fractionation trials confirmed the technical feasibility of separating high-molecular weight, antioxidant and reducing sugar fractions from cane juice in forms suitable for value recovery. It was also found that up to 40% of potassium salts from the juice can be removed by membrane application while removing the similar amount of water with potential energy saving in subsequent evaporation. Application of ISPP would allow sugar industry to co-produce multiple products and high quality mill sugar while eliminating energy intensive refining processes.

Optimisation of process parameters for the removal of hydroxycinnamic acids in sugar solutions

Colour is one of the most important parameters in sugar quality and its presence in raw sugar plays a key role in the marketing strategy of sugar industries worldwide. This study investigated the degradation of a mixture of colour precursors using the Fenton oxidation process. These colour precursors are caffeic acid, p–coumaric acid and ferulic acid, which are present in cane juice. Results showed that with a Fe(II) to H2O2 molar ratio of 1:15 in an aqueous system at 25 °C, 77% of the total phenolic acid content was removed at pH 4.72. However, in a synthetic juice solution which contained 13 mass % sucrose (35 °C, pH 5.4), only 60% of the total phenolic acid content was removed.

SOTrain: A new program for training supervisors and operators in Australian sugar factories

The provision of effective training of supervisors and operators is essential if sugar factories are to operate profitably and in an environmentally sustainable and safe manner. The benefits of having supervisor and operator staff with a high level of operational skills are reduced stoppages, increased recovery, improved sugar quality, reduced damage to equipment, and reduced OH&S and environmental impacts. Training of new operators and supervisors in factories has traditionally relied on on-the-job training of the new or inexperienced staff by experienced supervisors and operators, supplemented by courses conducted by contractors such as Sugar Research Institute (SRI). However there is clearly a need for staff to be able to undertake training at any time, drawing on the content of online courses as required. An improved methodology for the training of factory supervisors and operators has been developed by QUT on behalf of a syndicate of mills. The new methodology provides ‘at factory’ learning via self-paced modules. Importantly, the training resources for each module are designed to support the training programs within sugar factories, thereby establishing a benchmark for training across the sugar industry. The modules include notes, training guides and session plans, guidelines for walkthrough tours of the stations, learning activities, resources such as videos, animations, job aids and competency assessments. The materials are available on the web for registered users in Australian Mills and many activities are best undertaken online. Apart from a few interactive online resources, the materials for each module can also be downloaded. The acronym SOTrain (Supervisor and Operator Training) has been applied to the new training program.

Characterization and impact of the sugarcane borer on sugarcane yield and quality

The sugarcane borer, Diatraea saccharalis (F.) (Lepidoptera: Crambidae), is a key pest of sugarcane (Saccharum spp.). While damage caused by this pest has increased in the past 20 yr, studies investigating the insect-plant interactions are still lacking. Moreover, there is no information about the consequences of borer damage on the parameters of sugar quality. Therefore, two field experiments were performed during the 2010 and 2011 growing seasons in Brazil to compare the raw material and sugar quality of SP80-3280 sugarcane plants with and without the sugarcane borer. Plants were protected within screen cages and infested weekly during the 2010 and 2011 seasons, using egg masses starting at the second and third internode stage. At harvest, 25.77 and 19.01% of the internodes were bored by larvae (infestation intensity, II) in the first and second seasons, respectively. There was no correlation between the borer gallery total volume and II. The fiber content significantly increased with increasing II. The stalk biometric parameters, such as length, diameter, and yield, were not correlated with II. The sucrose yield significantly decreased with increasing II. Consequently, sugar yield losses were estimated at 8.83 and 19.80% per 1% bored internode for the first and second seasons, respectively. The concentration of phenolic compounds increased, and unclarified juice color quality decreased, with increasing II. Significant differences were detected in the quality of the sugar. These results should be confirmed for other sugarcane cultivars and incorporated into an economic injury level to enhance decision-making strategies for borer management. © 2013 by the American Society of Agronomy, 5585 Guilford Road, Madison, WI 53711. All rights reserved.

Use of Moringa oleífera Lamarck leaf extract as sugarcane juice clarifier: effects on clarifed juice and sugar

The objective of this study was to evaluate the effect of Moringa oleifera Lam. leaf extract on the sedimentation of impurities in the treatment of sugarcane juice and the effects on sugar quality and on the clarified juice. The experimental design used was a 4x2 factorial arrangement with four replications. The main treatments performed included the extracted original sugarcane juice, the synthetic polyelectrolyte (Flomex 9076), the leaf extract, and a control. The secondary treatments consisted of the sugarcane varieties RB92579 and RB867515. The clarification process used was simple defecation, in which the flocculating agents and the juice, limed and heated, were poured simultaneously into a decanter. The microbiological and chemico-technological characteristics of the extracted and clarified juices were evaluated. The clarified juice was concentrated up to 60° Brix (syrup) and subjected to boiling in a pilot pan using seeds to perform the graining: The sugar was recovered by centrifugation and analyzed for microbiological and chemico-technological characteristics. It was concluded that the use of the Moringa oleifera Lam. leaves extract resulted in a better quality of clarified juice and sugar.

Membrane filtration of clarified juice

A membrane filtration plant using suitable micro or ultra-filtration membranes has the potential to significantly increase pan stage capacity and improve sugar quality. Previous investigations by SRI and others have shown that membranes will remove polysaccharides, turbidity and colloidal impurities and result in lower viscosity syrups and molasses. However, the conclusion from those investigations was that membrane filtration was not economically viable. A comprehensive assessment of current generation membrane technology was undertaken by SRI. With the aid of two pilot plants provided by Applexion and Koch Membrane Systems, extensive trials were conducted at an Australian factory using clarified juice at 80–98°C as feed to each pilot plant. Conditions were varied during the trials to examine the effect of a range of operating parameters on the filtering characteristics of each of the membranes. These parameters included feed temperature and pressure, flow velocity, soluble solids and impurity concentrations. The data were then combined to develop models to predict the filtration rate (or flux) that could be expected for nominated operating conditions. The models demonstrated very good agreement with the data collected during the trials. The trials also identified those membranes that provided the highest flux levels per unit area of membrane surface for a nominated set of conditions. Cleaning procedures were developed that ensured the water flux level was recovered following a clean-in-place process. Bulk samples of clarified juice and membrane filtered juice from each pilot were evaporated to syrup to quantify the gain in pan stage productivity that results from the removal of high molecular weight impurities by membrane filtration. The results are in general agreement with those published by other research groups.

The composition of sugarcane juices dervied from burnt cane and whole green cane crop

There has been substantial interest within the Australian sugar industry in product diversification as a means to reduce its exposure to fluctuating raw sugar prices and in order to increase its commercial viability. In particular, the industry is looking at fibrous residues from sugarcane harvesting (trash) and from sugarcane milling (bagasse) for cogeneration and the production of biocommodities, as these are complementary to the core process of sugar production. A means of producing surplus residue (biomass) is to process whole sugarcane crop. In this paper, the composition of different juices derived from different harvesting methods, viz. burnt cane with all trash extracted (BE), green cane with half of the trash extracted (GE), and green cane (whole sugarcane crop) with trash unextracted (GU), were investigated and the results and comparison presented. The determination of electrical conductivity, inorganic composition, and organic acids indicate that both GU and GE cane juice contain a higher proportion of soluble inorganic ions and ionisable organic acids, compared to BE cane juice. It is important to note that there are considerably higher levels of Na ions and citric acid, but relatively low P levels in the GU samples. A higher level of reducing sugars was analysed in the GU samples than the BE samples due to the higher proportion of impurities found naturally in sugarcane tops and leaves. The purity of the first expressed juice (FEJ) of GU cane was on average higher than that of FEJ of BE cane. Results also show that GU juices appear to contain higher levels of proteins and polysaccharides, with no significant difference in starch levels.

Effect of trash on the coagulation and flocculation of sugarcane juice

The processing of juice expressed from whole green sugarcane crop (stalk and trash) leads to poor clarification performance, reduced sugar yield and poor raw sugar quality. The cause of these adverse effects is linked to the disproportionate contribution of impurities from the trash component of the crop. This paper reports on the zeta (ζ) potential, average size distribution (d50) and fractal dimension (Df) of limed juice particles derived from various juice types using laser diffraction and dynamic light scattering techniques. The influence of non-sucrose impurities on the interactive energy contributions between sugarcane juice particles was examined on the basis of Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. Results from these investigations have provided evidence (in terms of particle stability) on why juice particles derived from whole green sugarcane crop are relatively difficult to coagulate (and flocculate). The presence of trash reduces the van der Waals forces of attraction between particles, thereby reducing coagulation and flocculation processes. It is anticipated that further fundamental work will lead to strategies that could be adopted for clarifying juices expressed from whole green sugarcane crop.

Effect of trash on the coagulation and flocculation of sugarcane juice

The processing of juice expressed from whole green sugarcane crop (stalk and trash) leads to poor clarification performance, reduced sugar yield and poor raw sugar quality. The cause of these adverse effects is linked to the disproportionate contribution of impurities from the trash component of the crop. This paper reports on the zeta (?) potential, average size distribution (d50) and fractal dimension (Df) of limed juice particles derived from various juice types using laser diffraction and dynamic light scattering techniques. The influence of non-sucrose impurities on the interactive energy contributions between sugarcane juice particles was examined on the basis of Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. Results from these investigations have provided evidence (in terms of particle stability) on why juice particles derived from whole green sugarcane crop are relatively difficult to coagulate (and flocculate). The presence of trash reduces the van der Waals forces of attraction between particles, thereby reducing coagulation and flocculation processes. It is anticipated that further fundamental work will lead to strategies that could be adopted for clarifying juices expressed from whole green sugarcane crop.

Issues associated with using trash as a cogeneration fuel

Considerable work has been undertaken to determine an economical process to provide sugarcane trash as a fuel for cogeneration. This paper reviews efforts to provide that trash fuel by harvesting, transporting and processing the trash with the cane. Harvesting trash with the cane has the advantage that cane that would otherwise be lost by extracting it with the trash is captured and sugar can be produced from that cane. Transporting trash with the cane significantly reduces the bulk density of the cane, requiring substantial changes and costs to cane transport. Shredding the trash at the harvester and compacting the cane in the bin prior to transport are possible methods to increase the bulk density but both have considerable cost. Processing trash through the sugar factory with the cane significantly reduces sugar recovery and sugar quality. Although considerable knowledge has been gained of these effects and further analysis has provided insights into their causes, much more work is required before whole crop harvesting and transport is an economically viable means of trash recovery.