Modeling and optimization of wheat starch suspensions microfiltration

Cilj ovog rada je ispitivanje uticaja procesnih parametara (transmembranski pritisak, protok i koncentracija suspenzije) na vrednost fluksa permeata, sa i bez prisustva statičkog mešača, tokom procesa mikrofiltracije suspenzija pšeničnog skroba na keramičkim membranama različitih veličina pora (200 nm i 500 nm). Mikrofiltracija je izvođena u uslovima recirkulacije i koncentrisanja napojne suspenzije. Za modelovanje zavisnosti procesa mikrofiltracije suspenzija skroba od procesnih parametara primenjen je postupak odzivne površine. Ispitivanjem mikrofiltracije suspenzija pšeničnog skroba na membranama sa različitim srednjim prečnikom pora (200 i 500 nm) uočeno je da sa povećanjem veličine pora vrednost fluksa permeata opada. U posmatranom eksperimentalnom opsegu procesnih parametara postignuto je relativno povećanje stacionarnog fluksa od 25% do 50% u uslovima recirkulacije napojne suspenzije, dok je u uslovima koncentrisanja napojne suspenzije relativno povećanje srednjeg fluksa iznosilo od 20% do 80%. Porast fluksa do kojeg dolazi postavljanjem statičkog mešača u kanal membrane uslovljen je uspostavljanjem turbulentnih uslova proticanja i karakterističnog kretanja fluida duž kanala membrane, koja je posledica karakterističnog povezivanja helikoidnih elemenata Kenics statičkog mešača. Kako u uslovima recirkulacije napojne smeše, tako i u uslovima koncentrisanja, vrednost relativne specifične potrošnje energije zavisi skoro isključivo od vrednosti protoka napojne smeše. Sa povećanjem protoka specifična potrošnja energije u prisustvu statičkog mešača naglo raste i relativno povećanje protoka nije dovoljno da bi kompenzovalo gubitak hidrauličke snage. U opsegu protoka od 80 do 100 L/h su obezbeđene pozitivne vrednosti relativne promene specifične potrošnje energije, te je upotreba statičkog mešača opravdana sa ekonomskog aspekta. Optimizacija eksperimentalnih uslova urađena je postupkom istovremene maksimizacije fluksa permeata u sistemima sa statičkim mešačem i relativne promene specifične potrošnje energije. Optimalni uslovi izvođenja procesa mikrofiltracije suspenzija pšeničnog skroba u uslovima recirkulacije napojne suspenzije ukazuju da je proces potrebno izvoditi pri maksimalnoj vrednosti transmembranskog pritiska od 0,9 bara, protocima od 85 do 100 L/h i koncentraciji od 5 do 6 g/L. Optimalni uslovi izvođenja procesa mikrofiltracije suspenzija pšeničnog skroba u uslovima koncentrisanja napojne suspenzije ukazuju da je proces potrebno izvoditi pri vrednosti transmembranskog pritiska od 0,85 do 0,9 bara, protocima od 85 do 100 L/h i koncentraciji od 5 do 7 g/L. Pored ispitivanja na laboratorijskoj aparaturi, cilj ovog rada je bio i ispitivanje uticaja procesnih parametara na proces mikrofiltracije suspenzija skroba u poluindustrijskim uslovima (na jednokanalnoj i višekanalnoj membrani srednjeg prečnika pora 200 nm), odnosno šireg opseg vrednosti transmembranskog pritiska i protoka suspenzije na pomenute odzive u uslovima koncentrisanja napojne suspenzije.The aim of this study was to investigate the effect of process parameters (transmembrane pressure, flow rate and suspension concentration) on the permeate flux in the system with and without the presence of static mixer. Microfiltration of wheat starch suspensions was performed in recirculation and concentration mode using ceramic membranes with different pore size (200 nm and 500 nm). Response surface methodology was applied for modeling cross-flow microfiltration of starch suspensions. During investigation of starch suspension microfiltration process on membranes with different pore size diameter (200 and 500 nm) it was observed that with increasing pore size the permeate flux declined. In the experimental range of process parameters, flux increase had values between 25% and 50% in recirculation mode, while in concentration mode this improvement was in range between 20% and 80%. The increase in flux that occurs by placing a static mixer in the membrane channel was caused by the establishment of turbulent flow conditions and the characteristic flow of fluid along the membrane channel, which is a consequence of the characteristic geometry of Kenics static mixer. Both in recirculation and concentration mode, the reduction of specific energy consumption depends almost exclusively on the value of the suspension flow rate. Specific energy consumption increased rapidly with increasing flow rate in the presence of static mixers and flux improvement is not high enough to compensate the loss of hydraulic dissipated power. The flow rate in the range from 80 to 100 L/h provided positive values of the reduction of specific energy consumption and the use of static mixers was justified from the economical point of view. Optimization of experimental conditions was done by a procedure of simultaneous maximization of permeate flux in systems with static mixers and reduction of specific energy consumption. Optimal conditions of the wheat starch suspension microfiltration in recirculation mode indicate that the process should be conducted at the maximum value of transmembrane pressure of 0.9 bar, flow rates from 85 to 100 L/h and concentration of 5 to 6 g/L. Optimal conditions of the wheat starch suspension microfiltration in concentration mode indicate that the process should be conducted when the value of transmembrane pressure from 0.85 to 0.9 bar, flow rates from 85 to 100 L/h and concentration of 5 to 7 g/L. Apart from investigations in laboratory conditions, the aim of this study was to examine the influence of process parameters on the starch suspensions microfiltration in the pilot plant (one channel and multichannel membrane with pore diameter 200 nm) and wider range of transmembrane pressure and suspension flow rate on the mentioned responses in concentration mode

Data-driven Modelling of Microfiltration Process with Embedded Static Mixer for Steepwater from Corn Starch Industry

Cross-flow microfiltration using ceramic tubular membrane was applied for treatment of steepwater from corn starch industry. Experiments are conducted according to the faced centered central composite design at three different transmembrane pressures (1, 2 and 3 bar) and cross-flow velocities (100, 150 and 200 L/h) with and without the usage of Kenics static mixer. For examination of the influence of the selected operating conditions at which usage of the static mixer is justified, a response surface methodology and desirability function approach were used. Obtained results showed improvement in the average permeate flux by using Kenics static mixer for 211 % to 269 % depending on experimental conditions when compared to the system without the static mixer. As a result of optimization, the best results considering flux improvement as well as reduction of specific energy consumption were obtained at low transmembrane pressure and lower feed cross-flow rates

Environmetal friendly method in the sugar-beet production for the colourants removal

Despite the fact that the sugar industry is one of the causes of the environmental pollution, not enough has been done on its improvement. According to CEFS, specific energy consumption was 31.49 kWh/100 kg sugar beet. While the overall water used is about 15 m3 /t sugar beet processed, the consumption of fresh water is 0.25 – 0.4 m3 /t sugar beet processed, or even less in modern sugar factories. The separation operation deserves special attention because of its significant consumption of water end energy. Ultrafiltration could be one of the solutions for energy saving and more effective separation of coloured compounds (which during the crystallisation build into the sucrose crystals) from intermediate products from which sucrose directly crystallises. The aim of this experimental work is to determine the influence of operating parameters on the efficiency on coloured matter removal in high concentrated syrup. In this work syrup solution, which is an intermediate product in the phase of sucrose crystallisation, with 60% dry matter content, is the main feed. Experimental investigations were performed on 20 nm ceramic tubular membrane. Effects of colour removal on syrup solution are investigated at 60 and 80º C, in the range of transmembrane pressure between 4 and 10 bars. Optimal values of flow rates are chosen between 100 and 400 L/h. For defining the effects of the membrane separation process, permeate flux are determined. According to mentioned conditions colour is by 35 - 40 % in average, and turbidity is by 80% in average lower according to the feed. The permeate flux could be reached is 45 L/m2 h at flow rate 400 L/h and at 80o C

Environmental friendly method in the sugar-beet production for the colourants removal

Despite the fact that the sugar industry is one of the causes of the environmental pollution, not enough has been done on its improvement. According to CEFS, specific energy consumption was 31.49 kWh/100 kg sugar beet. While the overall water used is about 15 m3/t sugar beet processed, the consumption of fresh water is 0.25 – 0.4 m3/t sugar beet processed, or even less in modern sugar factories. The separation operation deserves special attention because of its significant consumption of water end energy. Ultrafiltration could be one of the solutions for energy saving and more effective separation of coloured compounds (which during the crystallisation build into the sucrose crystals) from intermediate products from which sucrose directly crystallises. The aim of this experimental work is to determine the influence of operating parameters on the efficiency on coloured matter removal in high concentrated syrup. In this work syrup solution, which is an intermediate product in the phase of sucrose crystallisation, with 60% dry matter content, is the main feed. Experimental investigations were performed on 20 nm ceramic tubular membrane. Effects of colour removal on syrup solution are investigated at 60 and 80 ºC, in the range of transmembrane pressure between 4 and 10 bars. Optimal values of flow rates are chosen between 100 and 400 L/h. For defining the effects of the membrane separation process, permeate flux are determined. According to mentioned conditions colour is by 35 - 40 % in average, and turbidity is by 80% in average lower according to the feed. The permeate flux could be reached is 45 L/m2h at flow rate 400 L/h and at 80 ºC

2D simulation and analysis of fluid flow between two sinusoidal parallel plates using lattice Bolzmann method

In order to obtain a better heat transfer, it is important to enhance fluid mixing in heat exchangers. Since there are negative effects when heat exchangers are operating in turbulent regime (like significant pressure drop, increased size of the pump) it is necessary to apply the techniques which would provide better fluid mixing when heat exchangers are operating in laminar regime. Investigations have shown that use of sinusoidal instead of flat plates results in this effect. This study is a result of two dimensional simulation of fluid flow between two parallel sinusoidal plates. Simulation was done with the use of modified Openlb code, based on lattice Boltzmann method. Reynolds number was varied from 200 to 1000, and space between the plates was varied from 3cm to 5 cm. Results showed that sinusoidal plates enhance fluid mixing, especially with greater values of Re and smaller space between the plates, which is in agreement with previous investigations

Analysis of the influence and optimization of concentration of organic acids on chemical and physical properties of wheat dough using a response surface methodology and desirability function

In order to improve physical and chemical properties of dough produced from wheat flour of suboptimal quality (protein content 10.7% dry basis, dough energy 4.0 cm2), optimal doses of ascorbic and citric acid were evaluated using a response surface methodology and desirability function. The paper brings the analysis of the main effects as well as their interactions. The effect of organic acids was evident in relation to pH lowering and decrease in free thiol groups, which consequently changed the physical properties of dough (increased dough energy, extensibility and resistance). The well known oxidative effect of ascorbic acid which is manifested as increase in dough energy and resistance, was enhanced by the addition of citric acid i.e. their synergistic action. Contribution of citric acid was the donation of hydrogen ions which changed the pH, lowered the content of free -SH groups and increased protein aggregation. Ascorbic acid individually significantly increased energy (linear regression coefficient b1 = 4.010-4) but higher effect was exerted by the addition of ascorbic and citric acid mixture as seen through higher interaction regression coefficient (b12 = 0.076). Dough resistance was significantly affected only by ascorbic acid due to its oxidizing action whereas dough extensibility was affected by both acids (main effects) at all applied doses and their mixtures. The effect on dough extensibility depends on the dose of acids but resistance decreased with quadratic increase of acid doses. Second-order polynomials were used in modeling of responses (dough energy, resistance and extensibility) which showed a good fit with experimental data as shown by high values of the coefficients of determination R2 for energy, resistance and extensibility (0.953, 0.976 and 0.996, respectively). Based on F value, it could be concluded that the model gave good prediction of experimental data while p-values for all responses showed that the models were significant at significance of 90%. The obtained models were used to optimize the doses of ascorbic and citric acid in order to maximize dough energy and extensibility. Significant increase of dough energy by 4.7 times and extensibility by 1.5 times was achieved by the set of optimum conditions of 97 mg/kg citric and 100 mg/kg ascorbic acid. The obtained results are applicable in semi-industrial and industrial facilities for flour processing

A Novel Approach for Simulation and Optimization of Rubber Vulcanization

The kinetic model, encompassing the curing and reversion phenomena of the NR/SBR rubber vulcanization process, was developed by means of the finite element method simultaneously with heat transfer equations, including heat generation due to curing reactions. The vulcanization simulation was conducted for three spheres of different diameters (1, 5 and 10 cm) and two rubber wheels, one of which was a commercial product of the rubber industry. The proposed advanced simulation model, based on products’ two-dimensional axisymmetry, includes cooling after vulcanization, during which the crosslinking reactions continue to take place as a result of the products’ heated interiors. As a criterion for removing the product from the mold, an average vulcanization degree of 0.9 was set, whereby, during cooling, the vulcanization degree increases, due to crosslinking reactions. Based on the minimal difference between the maximal and minimal vulcanization degrees, which did not exceed a value of 0.0142, the optimal process parameters for each product were determined, achieving homogeneity and obtaining high-quality rubber products, while simultaneously ensuring a more efficient vulcanization process and enhanced cost effectiveness for the rubber industry

UTICAJ UDELA SREDSTVA ZA EKSPANDIRANJE NA SVOJSTVA MIKROPOROZNIH ELASTOMERNIH MATERIJALA

Mikroporozni elastomeri predstavljaju prostorno umrežene makromolekule sa izraženom ćelijskom strukturom. Količine izabranih komponenti umrežavajuće smese određuju eksploataciona svojstva ovih materijala. Za specifične primene elastomera neophodno je ostvariti željeni nivo umreženja kao i gustinu materijala. U ovom radu ispitan je uticaj sadržaja sredstva za ekspandiranje na svojstva mikroporoznih materijala na osnovu terpolimera poli-(etilen-ko-propilen-ko-2-etiliden-5-norbornen) kaučuka (EPDM)umreženih sumporom i ojačanih česticama čađi. Variran je sadržaj sredstva za ekspandiranje (1,3; 1,8 i 2,0 phr). Ustanovljeno je da su dobijeni elastomerni materijali pogodni za primenu u oblasti proizvodnje zaptivnih profila za potrebe automobilske industrije

DRYING CHARACTERISTICS OF TRADITIONAL FERMENTED SAUSAGE PETROVSKÁ KLOBÁSA -THE EFFECT OF DIFFERENT RIPENING CONDITIONS AND USE OF STARTER CULTURE

ABSTRACT: A study was carried out on traditional Serbian dry-fermented sausage Petrovská klobása in order to investigate the effect of different ripening conditions and use of starter culture (SC) on drying characteristics of this typical meat product. The results related with reduction of diameter, water activity (a w ) and moisture content of sausages, obtained during ripening, indicated 30 days faster drying process in controlled industrial ripening room (RR) than in traditional room (TR) (60 vs. 90 days). Along with the ambient (thermo-hygrometric) conditions, this phenomenon was also determined by pH, which was lower in RR sausages (P<0.05), especially in those made with SC. High values of coefficient of determination (r 2 >0.992) indicate good fit of the experimental data (average moisture content vs. drying time) using third degree polynomial equation, both for RR and TR sausages, whether the samples were produced with or without SC. Additionally, the evolution of moisture content ratio between internal and external fractions of sausages indicated more intense drying in the external ones. This was particularly pronounced in sausages made with SC after 30 days of drying. The use of SC and RR in processing of Petrovská klobása seems to be a potential technological improvement to shorten the drying period and to prolong the production season of this traditional meat product