Concentrated Vinasse Research Articles

Recovery of Potassium from Pyrolysis Product of Sugar Fabrication Waste Carbonation Cake and Vinasse Mixture and Production of Adsorbent for Wastewater Treatment

In this study, percolation tests with water were carried out on the products that were subjected to pyrolysis and obtained in order to carbonize the organics in the vinasse carbonation cake mixtures. For this purpose, the mixtures prepared from the concentrated vinasse supplied from Sugar Factory and the carbonation cake supplied from Sugar Factory were heated at 500 °C for 4 h, and the extractability and dissolution rate of potassium into water were determined by leaking water over the products. The ability of the residue to remove methylene blue from the aquatic environment was determined. It should be emphasized that the solid residue from the potassium extraction has a considerable amount (289–370 mg/g) and a basic dye removal capacity greater than that of the raw carbonation cake (208 mg/g). COD value in the extract of the pyrolysis product with a cake/vinasse ratio of 0.5 was determined as 970 mg/l with a significant increase. The methylene blue removal capacity of the extraction residue samples obtained in this group of experiments decreases as the dry cake–vinasse ratio increases. It should be emphasized that the composite product obtained by taking advantage of these results can be actively used in the production of compound fertilizer.

Use of Plackett–Burman and Box–Behnken Designs to Optimize Bioelectricity Production from Winery Residues

This study aimed to estimate the bioelectricity production process using a vinasse solution through the application of Plackett–Burman and Box–Behnken designs. An electrochemical cell was constructed using Arduino to measure the potential difference between an anode and cathode immersed in a vinasse solution, which is a byproduct of wine production containing organic compounds and ions that undergo redox reactions. The Plackett–Burman design identified the most influential variables among eight previously selected (concentration of the electrolyte, pH, temperature, stirring, addition of NaCl, yeast dose and electrode:solution ratio). The results showed that the most influencing variables were the vinasse concentration and stirring and a peak of 306 mV could be observed for a 100 mL experiment. The third most influential variable regarding the process was NaCl addition, which showed its high influence at larger times. Based on these results, the Box–Behnken design was used to determine the possible ranges of variation of the independent variables (vinasse concentration, stirring and NaCl dose) to maximize the bioelectricity production. Therefore, with the combination of the intermediate concentrated vinasse (1:3 v/v ratio) and stirring, a peak of 431.1 mV could be observed when adding 2% NaCl after 15 min of the experiment. In what concerns the instant bioelectricity, measured after 1 min of the experiment, values up to 437.9 mV could be observed although yeast and/or NaCl are necessary at short times. This study provides insights into the bioelectricity production process from vinasse, contributing to the understanding and potential for sustainable energy generation.

New trends in sugarcane fertilization: Implications for NH3 volatilization, N2O emissions and crop yields

Recycling nutrients helps to reduce the environmental impact of agriculture and contributes to alleviating the effects of global climate change. A recent trend in sugarcane cultivation is the application of concentrated vinasse (CV) combined with fertilizers into an organo-mineral formulation to improve logistics, reduce costs and foster the circular economy. However, the implications of the application of such organo-mineral formulation in sugarcane fields are unclear. In this study, we evaluated the effects of the organo-mineral formulation containing granular urea (UR), and a nitrification inhibitor (NI) on crop yields, NH3 volatilization, and N2O emissions. Field experiments were conducted during two fertilization seasons, dry and wet, and the treatments were: control; UR; UR + NI; CV; CV + UR; and CV + UR + NI. CV was applied at 7 m3 ha−1. The treatments (except control and CV) were balanced to receive the same amount of N and K. Compared with UR, the organo-mineral formulation of CV + UR decreased NH3 volatilization losses from 7% to 4% in the dry season and from 3.5% to 0.5% in the wet season. Conversely, compared with UR, N2O emissions increased significantly (p ≤ 0.05) in CV + UR in the wet season from 1% to 2% of applied N. In the dry season, no differences were observed. The addition of NI was effective in mitigating N2O emissions in both seasons. Emission reductions ranged from 43 to 48% in the dry season and from 71 to 84%, in the wet season. Fertilization with UR or the organo-mineral formulation influenced sugarcane yield only in the dry season, with the highest yield in CV + UR. NI did not affect crop yield. In general, emission intensities (kg CO2eq Mg−1 of stalk) were highest in CV + UR. We conclude that the organo-mineral formulation reduced NH3 losses and increased N2O emissions compared with regular solid fertilizer and that NI was effective for mitigating N2O emissions.

Comparative characteristics of native (liquid) and concentrated up to 40 % vinasse as a raw material for anaerobic fermentation

The energy crisis that is currently taking place in Ukraine requires an active search for alternative energy sources. Ukraine provides itself with natural gas and oil of its own production only by 20 %. With the help of biogas technologies, it is possible to increase the share of energy from renewable sources, reduce the amount of waste generation, and limit greenhouse gas emissions. Biogas is produced as a result of methane fermentation of biomass. There is a significant problem with the waste of bioethanol production – beet vinasse, a dark-colored liquid with an unpleasant odor. Anaerobic fermentation technologies are the basis for the disposal of organic waste in the world. Vinasse concentration is one of the alternatives with which can be the efficiency of anaerobic digestion and reduce the negative economic and environmental consequences of applying large volumes of vinasse in the fields. Studies show that concentrated vinasse is more suiTable for methane fermentation than liquid vinasse. The process of concentrating vinasse is economically beneficial for plants, as it will reduce the size and cost of building biogas reactors and can facilitate the management and processing of vinasse. An additional advantage of using methanogenesis for waste utilization is obtaining the digestate – the product after methane fermentation and obtaining the main product − biogas. It can also be successfully used in agriculture as a fertilizer. It has many nutrients and does not pollute the environment, as it is free from fermentation products. The proposed technologies will allow sugar and alcohol plants to carry out waste-free production, receiving the main product biogas to meet their own energy needs, and digestate

Soil pH does not interfere with nitrification inhibitor efficiency for reducing N2O emissions from soils treated with concentrated vinasse and urea

This study addresses the assessment of potential nitrification inhibitor (NI) 3,4-dimethylpyrazol-phosphate for mitigation of nitrous oxide (N2O) emissions from the joint application of concentrated vinasse (CV) and urea in soils under different pHs. An incubation experiment was performed under controlled conditions to evaluate the effect of the organo-mineral fertilization containing CV and Urea (N rate: 120 kg N ha−1) on N2O emissions, as well as the efficiency of the NI addition, at different soil pHs (4.5 and 6.0). The treatments were: Control; Urea; Urea + NI; CV; CV + Urea; and CV + Urea + NI. The soil pH greatly influenced the N2O production with emissions 3.8-fold higher at pH 6.0 than at pH 4.5. Besides, the joint application of CV + Urea increased the N2O emissions by 1.3 and 2.9-fold (185 and 1141 mg N m−2) compared to Urea treatment (138 and 391 mg N m−2) at pH 4.5 and 6.0, respectively. The addition of NI was efficient under both soil pHs, decreasing N2O emissions by 92 and 88 % in the Urea treatment and 71 % and 91 % in the CV + Urea treatment at pH 4.5 and 6.0, respectively. Our results indicate that soil pH has a large influence on N2O emissions and little effect on the NI efficiency.

Vinasse improves soil quality and increases the yields of soybean, maize, and pasture

ABSTRACT Vinasse can be a suitable alternative to improve soil attributes and increase crop yield. This study evaluated the effect of fresh and concentrated vinasse on soil chemical and biological attributes and on the yields of soybean, maize, and pasture. The design was in randomized blocks with four replications and five treatments: T1 (250 kg ha-1 08:28:16 at sowing + 40 kg ha-1 K2O at topdressing); T2 (250 kg ha-1 08:28:16 at sowing + 2450 L ha-1 of fresh vinasse at topdressing); T3 (250 kg ha-1 08:28:16 at sowing + 190 L ha-1 of concentrated vinasse at topdressing); T4 (4100 and 2450 L ha-1 of fresh vinasse at sowing and topdressing, respectively); T5 (315 and 190 L ha-1 of concentrated vinasse at sowing and topdressing, respectively). These treatments were applied during the soybean growth in 2017 and 2018. After soybean harvesting and before maize and pasture in 2018, soil chemical and biological attributes were assessed. Vinasse increased the concentrations of carbon and phosphorus, while decreasing those of potassium and sulfur. Vinasse reduced the carbon concentration of the microbial biomass by 50%, but increased the nitrogen concentration of the microbial biomass by 67%. The activity of dehydrogenase was higher with the application of fresh vinasse. Application of vinasse for two years improves soil chemical and biological attributes and increases the yields of soybean, maize, and pasture.

Scale-up and energy estimations of single- and two-stage vinasse anaerobic digestion systems for hydrogen and methane production

This study evaluated the full-scale vinasse anaerobic digestion for industrial application. Twelve scenarios were simulated, considering single (methanogenic reactor) and two-stage systems (acidogenic + methanogenic reactors), raw and concentrated vinasse, thermophilic and mesophilic conditions for methanogenesis and usage of acidogenic or methanogenic reactor effluent to dilute vinasse. A single-stage anaerobic digestion system of 17,433 m³ necessary to treat all the raw vinasse produced by a mill with a grinding capacity of 3.3 million tons of sugarcane per season can generate a power of 11.1 MW with an energy yield of 4.6 MJ/kg CODremoved. Two-stage system scenarios where vinasse was diluted with acidogenic reactor effluent had worse energetic recoveries than the single-stage system. Nonetheless, the usage of the methanogenic reactor effluent to dilute vinasse and its own influent in a two-stage system achieved an energetic recovery at least 34% higher than that of the single-stage system. In the best two-stage scenario, the total working volume was 19,666 m³, combining thermophilic acidogenic reactors and mesophilic methanogenic reactors, with an energy yield of 7.0 MJ/kg CODremoved. The different combinations of temperatures allow for a safer and more economic operation. The proposed novel industrial configuration can be divided into two parallel acidogenic reactors of 1,800 m³ each, and those reactors are in series with eight parallel methanogenic reactors of 2,828 m³ each. The electricity produced by the full-scale system can supply an energy demand of 24 thousand inhabitants per harvest season (9.7 kWh per ton of sugarcane). This study presents a novel discussion for sugarcane industry decision makers, such as plant managers, process and project engineers, providing a trade-off between highest energy production, optimal COD removal and lowest reactor volume (CAPEX investment) that better fits their needs.

DMPP mitigates N2O emissions from nitrogen fertilizer applied with concentrated and standard vinasse

The application of vinasse, an organic byproduct of ethanol production, can enhance greenhouse gas emissions from N fertilizers, especially nitrous oxide (N2O). The objective of this work was to test the efficiency of the nitrification inhibitor (NI) 3,4 dimethylpyrazole phosphate (DMPP) in reducing N2O emissions from urea (UR) and ammonium nitrate (AN) applied with or without standard (V) or concentrated vinasse (CV). Two laboratory studies were conducted with repacked soil columns from a sugarcane field. Based on usual field rates, UR and AN were added at a rate equivalent to 100 kg N ha−1, V was added at 100 m3 ha−1 (51 kg N ha−1), and CV was added at 20 m3 ha−1 (Exp. 1: 35 kg N ha−1 and Exp. 2: 56 kg N ha−1). N2O emissions were measured for 75 and 61 days after the input of fertilizers and vinasses. When mineral fertilizers were compared, the N2O-N emission factors (EFs) were: 0.08% (AN) and 1.44% (UR). Combined with N fertilizers, vinasses (CV and V) greatly enhanced the N2O emissions from soil (ranging from 0.76% to 1.5% in one study and 1.37% to 6.27% in the other). In addition, CV + N fertilizer emitted more N2O than V + N fertilizer or N fertilizer alone. However, NI reduced N2O emissions by 80% on average for vinasses (CV and V) plus N fertilizer (AN and UR) and UR alone, but not for AN alone. Since both vinasses and mineral N fertilizers are standard inputs for sugarcane production and high N2O emissions are observed when they are applied in the same area, NI should be considered for mitigation of soil N2O emissions from sugarcane used for bioenergy.

Immediate and Residual Effects of Mineral and Organomineral Nitrogen Sources Associated with Concentrated Vinasse on Maize

Owing to the great availability of N sources for agriculture, its complexity in the system, and the demand for new organic sources of nutrients, especially NPK, this study aimed to evaluate the immediate and residual effects of mineral and organomineral sources of N, in combination with different doses of K from concentrated vinasse (CnV), on the performance of the corn crop and the soil electrical conductivity (EC). The study was carried out in an air-conditioned greenhouse, in pots filled with Oxisol. The treatments were four N sources, comprising mineral ammonium sulfate, organomineral ammonium sulfate, mineral urea, and organomineral urea, in combination with four doses of K (K2O), applied in the form of CnV, at doses of 0, 100, 200, and 300 mg kg−1. Three vegetative cycles were conducted, so the immediate effects were assessed in the first cycle and the residual effects in the second and third cycles. The organomineral ammonium sulfate source promoted the best performance in the maize crop, while K doses were 300 and 200 mg kg−1, and interactions between these factors were more significant than their single effects. EC increased in the surface soil with the application of K; the highest peaks were observed in the first cycle of maize cultivation and the initial values were not reestablished for the remainder of the study. There were large increases in EC mainly in the first cycle, however only in the most superficial layer of the soil (immediate residual). The values decreased with each cycle, but there was no reestablishment of the initial levels, even 340 days after the last CnV application; the performance of maize was higher with the increased residual doses of K and sources of N, when compared to the immediate effect; the N source that was most beneficial to the corn crop was organomineral ammonium sulfate, in combination with the highest K doses from CnV; the combination of CnV and N sources helped to improve the performance of N mineral and organomineral fertilizers.

Potassium struvite (slow release fertilizer) and activated carbon production: Resource recovery from vinasse and grape marc organic waste using thermal processing

This study investigated the production conditions of a potassium magnesium phosphate fertilizer with vinasse (a by-product of the sugar or ethanol industry) and grape marc (a by-product of the wine-making industry). A mixture of vinasse and grape marc was subjected to pyrolysis under a nitrogen gas atmosphere, and water was used to extract potassium from the end product. Potassium magnesium phosphate (potassium-struvite, KMgPO4.6H2O), a slow-release fertilizer compound, was obtained from the extract with potassium to explore process conditions and product characteristics. Producing fertilizer products from residual materials is of paramount significance for conserving natural resources. The mixture was pyrolyzed, allowing us to remove potassium from the complex matrix of concentrated vinasse to a clear and high alkaline solution. The residual carbon was activated by decomposing (pyrolysis) and treating the residue and then washing it with water. The extract had high alkalinity, suggesting that the potassium in the mixture resulted in carbon activation during biomass pyrolysis. Pyrolysis and treatment can be used to produce activated carbon from vinasse. This study also investigated the solubility of vinasse in water and aqueous solutions. K-struvite with 10.67 % K2O was about 2% soluble in water, indicating that the end product was a slow-release fertilizer agent. In conclusion, this process can be used to produce potassium (a slow-release fertilizer) and activated carbon (a by-product) from vinasse for different purposes.

Techno-Economic Evaluation and GHG Emission Assessment of Different Options for Vinasse Treatment and Disposal Aiming at Reducing Transport Expenses and Its Energy Use

The vinasse is a polluting effluent generated in large quantities in the ethanol production process, whose disposition is problematic and costly. In this work, the vinasse problem is addressed through a comparison between four alternatives for treating it with energy recovery: (i) concentration in an evaporator system until 25 Brix for volume reduction (CONC); (ii) concentration in an evaporator system until 65 Brix, with subsequent incineration of concentrated vinasse (CONC + INC); (iii) anaerobic biodigestion (BIOD); and anaerobic biodigestion and digestate treatment by membranes (BIOD + MEM). The techno-economic assessment is performed through mass and energy balances, evaluating two configurations of the cogeneration system: considering back-pressure (BPST) and condensing-extraction (CEST) steam turbines, in combination with an economic feasibility evaluation. Furthermore, an evaluation of GHG emission was performed in each case. The BIOD + MEM and CONC cases promoted a significant reduction in effluent volume (53% and 82.8% respectively), while the CONC + INC case practically eliminated the disposal expenses of this effluent. Regarding the cogeneration system, the BIOD case presented the highest bagasse surplus (59.9 kg/t cane) for the BPTS configuration, while the CONC + INC case presented the highest electricity surplus (89.7 kWh/t cane) for the CEST configuration. As for the economic assessment, the cases CONC with BPST, and CONC + INC for both BPTS and CEST presented economic feasibility, while the GHG emission assessment indicates that the BIOD case with BPST is the option with the lowest emissions. A sensitivity analysis was also performed to evaluate eventual variations in market and operating conditions.

Simulación de la concentración e incineración como alternativa para el tratamiento de vinazas

In the present work the possibility of the concentration and incineration of the vinasse obtained in a Cuban rum factory was evaluated as an alternative for its treatment and to generate electricity. Simulation with ASPEN PLUS v7.2 was used as process analysis tool. A simulation model of the concentration process was obtained and models reported by the literature were used to simulate the incineration and generation of electricity. The model was validated with the real data of the process with a maximum validation error 5,5 % for the total condensates. The necessary conditions were determined to increase the final concentration of the vinasse up to 60 ºBrix. The flow of concentrated vinasse was reduced by 48%, the problem of production shutdowns due to the unavailability of stillage storage was solved and 87 kg/h of potassium rich ash and 632 kW of electric power were obtained. Likewise, an economic analysis was carried out that demonstrated the feasibility of applying the proposed technology.

Comparison through energy, exergy and economic analyses of two alternatives for the energy exploitation of vinasse

The vinasse, effluent generated in the distillation step of the ethanol production process, has polluting characteristics and is generated in large amounts, making its disposition problematic and costly. The present study addresses the vinasse problem through a comparison between two alternatives for the energy use of it: i) vinasse concentration and subsequent incineration of concentrated vinasse; and ii) vinasse anaerobic biodigestion. A simulation of a base case; namely, a conventional sugar and ethanol production process, was performed using the Aspen Plus® software. The comparison was carried out through energy, exergy and economic analyses. The energy analysis evaluates the impacts of these technologies in the cogeneration system, while the exergy analysis comprises the calculation of irreversibilities and exergy efficiencies. Finally, the economic analysis includes the calculation of costs and revenues of each alternative, in order to evaluate their feasibility. Additionally, a sensitivity analysis was performed. Results show that energy and exergy efficiencies are in the same range for both alternatives; however, the economic assessment indicated the vinasse incineration as the best alternative for the assumed conditions.

EFFECT OF VINASSES, MOLASSES AND MINERAL FERTILIZATION ON NODULATION AND GROWTH OF COMMON BEAN (PHASEOLUS VULGARIS L.) GROWN IN SANDY RECLAIMED SOILS

The present work was conducted to achieve the following aims:Evaluate the effect of both individual and combined applications of either of molasses or concentrated vinasse with mineral fertilizers i.e. phosphoric acid and mixture of micronutrients (Fe-Zn-Mn-Cu-B-Mo), which added in equal five dosses at different growth times to two cultivars of common bean plants (Phaseolus vulgaris L.) i.e, Karnak and Nebraska grown in sandy soil under drip irrigation systems on: nodulations efficiency, dehydrogenase activities at growth period of 45 days. As well as the dry matter yield of common bean plants and was determined, at growth periods of 45 and 70 days. The obtained data of this study show that, the two local cultivars of common bean plants (Karnak and Nebraska) appeared a wide variations to the studied treatments. The fertilization treatments under study resulted in a significant increase of nodules number formed on the roots, dehydrogenase activity and dry matter yields, where the highest values were found with Nebraska cultivar compared with those of Karnak cultivar.

Bacterial community composition and diversity of two different forms of an organic residue of bioenergy crop.

The use of residue of sugarcane ethanol industry named vinasse in fertirrigation is an established and widespread practice in Brazil. Both non-concentrated vinasse (NCV) and concentrated vinasse (CV) are used in fertirrigation, particularly to replace the potassium fertilizer. Although studies on the chemical and organic composition of vinasse and their impact on nitrous oxide emissions when applied in soil have been carried out, no studies have evaluated the microbial community composition and diversity in different forms of vinasse. We assessed the bacterial community composition of NCV and CV by non-culturable and culturable approaches. The non-culturable bacterial community was assessed by next generation sequencing of the 16S rRNA gene and culturable community by isolation of bacterial strains and molecular and biochemical characterization. Additionally, we assessed in the bacterial strains the presence of genes of nitrogen cycle nitrification and denitrification pathways. The microbial community based on 16S rRNA sequences of NCV was overrepresented by Bacilli and Negativicutes while CV was mainly represented by Bacilli class. The isolated strains from the two types of vinasse belong to class Bacilli, similar to Lysinibacillus, encode for nirK gene related to denitrification pathway. This study highlights the bacterial microbial composition particularly in CV what residue is currently recycled and recommended as a sustainable practice in sugarcane cultivation in the tropics.

Nitrogen-Enriched Vinasse as a Means of Supplying Nitrogen to Sugarcane Fields: Testing the Effectiveness of N Source and Application Rate

Vinasse is a by-product generated during the distillation phase of ethanol production. Vinasse can be concentrated and enriched with N to be used as a means of supplying nitrogen (N) to sugarcane fields. However, it remains necessary to ascertain the most effective N source and application rate to be mixed with concentrated vinasse (CV) in order to maximize crop productivity. In this study, we aimed to address three major questions: (i) which is the best combination of N source [urea or uran (urea + ammonium nitrate)] and application rate (0, 40, 80 or 120 kg ha−1 of N) to mix with CV; (ii) can the addition of acid fertilizers (boric acid and phosphoric acid) to CV reduce the volatilization of NH3 and/or increase sugarcane yield; and (iii) is there a correlation between the N–NH3 volatilization loss and the sugarcane yield. We conducted a sugarcane field trial to coincide with the second ratoon during the dry season. Applying N-enriched CV to sugarcane straw yielded only nominal NH3 losses. This outcome was attributed to a deficit in the water supply which limited urea hydrolysis and ammonia formation during the dry season. The addition of acid fertilizers (boric acid and phosphoric acid) was able to further reduce volatilization losses. Both, urea and uran appear to be feasible N sources for the enrichment of CV as they did not differ in their degree of accumulated NH3 volatilization. In terms of crop productivity, however, the use of uran appears to equate to greater sugarcane yield and leaf N content. The N rate of 80 kg ha−1 provides lower accumulated NH3 volatilization along with a higher sugarcane yield reflected in the correlation with productivity parameters. Our results suggested that application of CV enriched with N offers a promising means of improving sugarcane yield.

Decomposition of the organic matter of natural and concentrated vinasse in sandy and clayey soils

Vinasse has been used as fertilizer by sugarcane growers, due to its potential to completely replace mineral fertilizers. However, if the application is not adequate, this practice may cause environmental contamination. This study used a respirometry test to evaluate the organic matter (OM) decomposition present in natural vinasse and concentrated vinasse (CV), with or without urea addition. The experiment involved two soil types and two types of vinasse at different application rates. The vinasse chemical characterization showed high levels of pseudo-total potassium (K) in both vinasses, which are not considered in the application rates. Decomposition rates above 90% and between 70 and 80% were obtained for sandy and clayey soils, respectively, over a brief 41-day period, indicating rapid OM decomposition. Positive priming effect was observed for CV and CV + urea treatments in sandy soil. An important implication of these findings revealed that K not available in vinasse was released in the soil solution by the OM mineralization, indicating the possibility of overestimation in the vinasse application rates. Therefore, K pseudo-total values should be considered in the calculation of the vinasse application rates. However, studies involving K mobility into soil are needed to validate this hypothesis.

Combined Application of Concentrated Vinasse and Nitrogen Fertilizers in Sugarcane: Strategies to Reduce Ammonia Volatilization Losses

Ethanol is an alternative source of renewable fuel, but increasing production of vinasse as a by-product requires proper management. Combining concentrated vinasse (CV) and nitrogen (N) fertilizer into a single operation is increasing in Brazil. However, the chemical stability and potential for volatilization losses remain unknown. Our objectives were to characterize the chemical stability of CV and N fertilizer mixtures and to evaluate volatilization losses following application to sugarcane trash. In an initial study, we monitored variations in pH, total N and inorganic N content after a 22-day incubation of mixtures of CV and N fertilizer. In a second study, we evaluated N-NH3 volatilization losses following surface application to sugarcane trash. We used a medium-textured soil covered with trash (8 Mg ha−1), and measurements of N-NH3 losses were taken using acid traps in semi-static chambers during 40 days after mixture application. The addition of urea to the CV did not increase the pH and resulted in the maintenance of N in amidic form, demonstrating the chemical stability of the mixture. However, after application to sugarcane trash, N losses from urea added to the CV ranged from 29 to 35 % of the applied N. The addition of phosphoric acid and boron has the potential to reduce the N loss of 26 % of the applied N. The use of UAN mixed with CV had the lowest loss through volatilization (21 % of applied N) and is the suggested to use for application to sugarcane trash.

Multiobjective optimization of a sugarcane biorefinery involving process and environmental aspects

Process modeling and simulation are essential to predict process energetic demands, and determine possible throughputs and process emissions in biorefineries. In this paper non-linear multiobjective optimization studies with conflicting process and environmental objectives are performed in a sugarcane biorefinery. The process produces bioethanol (first and second generation), bioelectricity and concentrates vinasse in multiple-effect evaporators. Objective functions, concerning process and environmental issues, are defined and studied in five optimization problems. Decision variables are fraction of bagasse diverted to E2G production (Var1), and the fraction of vinasse that is concentrated up to 7.0°Bx in multiple-effect evaporator (Var2). The results show that Var1 cannot assume values greater than circa 0.5, due to thermal demands of the integrated process, while Var2 cannot be lower than 0.15, due to process demands for vegetal steam. Flows of concentrated vinasse are generally higher when maximization of bioethanol throughputs is imposed. When electric power generation and bioethanol throughput maximization are the objectives, the former varies 45.6%, while the latter varies 16.6%, among non-dominated solutions. The adopted approach can be used as a decision-making tool that may help to choose suitable operating conditions, in order to obtain a trade-off between greater profits and a more sustainable process.

Technology for sugarcane agroindustry waste reuse as granulated organomineral fertilizer

Aiming to evaluate the use of sugarcane industry waste such as byproducts from vinasse concentration process, it was assessed the organomineral fertilizer BIOFOM (concentrated vinasse, filter cake, boiler ash, soot from chimneys and supplemented with mineral fertilizers). The study included characterization and agronomic potential analysis of a test plant (corn), by noting the differences between mineral fertilizers and BIOFOM fertilization until 45 days after sowing. The technology traditionally used to produce BIOFOM was based on vinasse evaporation with high heat transfer coefficients. It was observed that the technology, which can be formulated according to the needs of any crop, could be used in many cases as mineral fertilizer. Therefore, the use of this organomineral fertilizer reduces waste generation of sugarcane industry.