R Z J a b c a A R R 1 A A K B E F R T S 1 r t i 3 I c e a c p f o p t s t i k 1 d Biochemical Engineering Journal 53 (2011) 260–265 Contents lists available at ScienceDirect Biochemical Engineering Journal journa l homepage: www.e lsev ier .com/ locate /be j heology and fluid dynamics properties of sugarcane juice ailer Astolfi-Filhoa,b, Vânia Regina Nicoletti Telisa, Eduardo Basilio de Oliveirac, ane Sélia dos Reis Coimbrac, Javier Telis-Romeroa,∗ Universidade do Estado de São Paulo (UNESP), Departamento de Tecnologia e Engenharia de Alimentos, CEP 15054-000 São José do Rio Preto, SP, Brazil COSAN S.A. Indústria e Comércio, Bairro Água da Aldeia s/n, Unidade Taruma, Polo Regional de Assis, CEP 19820-000 Tarumão, SP, Brazil Universidade Federal de Viçosa (UFV), Departamento de Tecnologia de Alimentos, CEP 36571-000 Viçosa, MG, Brazil r t i c l e i n f o rticle history: eceived 22 July 2010 eceived in revised form 0 November 2010 ccepted 12 November 2010 vailable online 23 November 2010 a b s t r a c t The sugarcane juice is a relatively low-cost agricultural resource, abundant in South Asia, Central America and Brazil, with vast applications in producing ethanol biofuel. In that way, a good knowledge of the rheological properties of this raw material is of crucial importance when designing and optimizing unit operations involved in its processing. In this work, the rheological behavior of untreated (USCJ, 17.9 ◦Brix), clarified (CSCJ, 18.2 ◦Brix) and mixed (MSCJ, 18.0 ◦Brix) sugarcane juices was studied at the temperature range from 277 K to 373 K, using a cone-and-plate viscometer. These fluids were found to present a eywords: ioprocess thanol riction factor heological properties emperature Newtonian behavior and their flow curves were well-fitted by the viscosity Newtonian model. Viscosity values lied within the range 5.0 × 10−3 Pa s to 0.04 × 10−3 Pa s in the considered temperature interval. The dependence of the viscosity on the temperature was also successfully modeled through an Arrhenius- type equation. In addition to the dynamic viscosity, experimental values of pressure loss in tube flow were used to calculate friction factors. The good agreement between predicted and measured values confirmed the reliability of the proposed equations for describing the flow behavior of the clarified and es. ugarcane untreated sugarcane juic . Introduction Sugarcane is an abundant and relatively low cost agricultural esource, largely produced in tropical and sub-tropical regions of he planet. This raw material contains about 80–85% of water and ts dry matter presents an average composition of approximately 0% sucrose and 70% pre-processed ligno-cellulosic materials [1]. n previous years, sugarcane, either in the form of cane juice or ane molasses, has been widely used as feedstock for producing thanol fuel in tropical and sub-tropical countries [2]. The sug- rcane ethanol has the advantage of generating energy from a lean and renewable resource and contributes to reduce both air ollution and greenhouse gas emission, when compared to fossil uels [3]. So, one important focus in current research and devel- pment applied in fuel ethanol production is the engineering of rocess to improve the productivity, by optimizing the unit opera- ions involved in the productive chain [3,4]. Indeed, in preliminary teps of ethanol production, numerous unit operations requiring he knowledge of fluid rheology and dynamics (e.g., pumping, heat- ng, cooling, sedimentation, etc.) are applied. For this purpose, the nowledge of rheological properties of the untreated sugarcane ∗ Corresponding author. Tel.: +55 17 3221 2250; fax: +55 17 3221 2299. E-mail address: javier@ibilce.unesp.br (J. Telis-Romero). 369-703X/$ – see front matter © 2010 Elsevier B.V. All rights reserved. oi:10.1016/j.bej.2010.11.004 © 2010 Elsevier B.V. All rights reserved. juice (USCJ), clarified sugarcane juice (CSCJ) and mixed sugar- cane juice (MSCJ) should be of utmost importance to the ethanol industry. A schematic representation of the process line before fer- mentation step, identifying each type of sugarcane juice, is shown in Fig. 1. As depicted in this figure, the unclarified juice (USCJ) is the material obtained from the sugarcane milling and pre-filtration (to remove bagasse pieces). The clarified (CSCJ) is obtained from the USCJ after its heating and settling; it is the supernatant obtained in this unit operation. Finally, the mixed juice (MSCJ) results from the mixing of USCJ and filtered sugarcane juice (FSCJ), which is the permeate obtained after the filtration of the previously settled juice. Literature reports a large number of fluids exhibiting a non- Newtonian behavior, such as diverse kinds of sludge [5,6]; and biological fluids, such as sucrose-CMC model solution [7], supersat- urated sucrose solutions [8], dairy cattle manure [9] and aqueous solutions of sucrose, glucose and fructose [10]. Moreover, data con- cerning the influence of temperature on the rheological and flow behaviors of biological fluid products with varied sucrose contents, such as fruit purées [11], coffee extract [12], honey [13], sourcherry juice and concentrate [14] and pineapple juice at different stages of maturity [15] can be found. Nevertheless, to our knowledge, such kind of data for sugarcane juices is not available. Considering this lack of published information on rheology and fluid dynamics of USCJ, CSCJ and MSCJ, this work intended to determine their rheo- logical properties and to develop simple correlations for predicting dx.doi.org/10.1016/j.bej.2010.11.004 http://www.sciencedirect.com/science/journal/1369703X http://www.elsevier.com/locate/bej mailto:javier@ibilce.unesp.br dx.doi.org/10.1016/j.bej.2010.11.004 Z. Astolfi-Filho et al. / Biochemical Engineering Journal 53 (2011) 260–265 261 Nomenclature A empirical constant in Eq. (14) D diameter (m) �P pressure drop (Pa) Ea activation energy for flow (J/mol) f friction factor K consistency index (Pa sn) L length (m) n flow behavior index R universal gas constant (8.314 J/mol K) Re Reynolds number Reg generalized Reynolds number T temperature (K) v velocity (m/s) Symbols ε roughness (m) �̇ shear rate (s−1) � viscosity (Pa s) � density (kg/m3) � shear stress (Pa) �0 yield stress (Pa) �w shear stress at the tube wall (Pa) Table 1 Soluble solids (SS, ◦Brix) polarizable sugars (Pol. mass), purity (100 × Pol./◦Brix), total solids (%) and pH for the studied sugarcane juices. ◦Brix Pol. Purity (%) Total solids (%) pH t r fl T e 2 2 a s t d P s S r i s s s s 2 r g USCJ 17.9 14.7 82.1 19.1 7.2 MSCJ 18.0 14.9 82.8 18.8 6.8 CSCJ 18.2 16.1 88.5 18.2 6.1 hese properties under different temperatures. Additionally, the heological data were used to calculate friction factors for tube ow, based on the widely accepted correlations described above. hese results were then compared with those determined from xperimental values of pressure loss in tubes. . Materials and methods .1. Sugarcane juice composition Sugarcane juices were collected from a local sugarcane company nd were quantified in terms of the following parameters. Soluble olids (SS, ◦Brix mass%) were determined using a digital refrac- ometer (Pal 3, Atago Japan). Polarizable sugars (Pol., mass%) were etermined with a digital polarimeter (P3000, Kruess Optronic). urity was calculated as 100 × Pol./◦Brix. Values of pH were mea- ured using a digital pH meter-termometer (Marconi, PA 200 P). uch parameters are those usually employed to characterize the aw sugarcane in a factory. Table 1 presents the values obtained n triplicate for the mentioned quality parameters of untreated ugarcane juice (USCJ), clarified sugarcane juice (CSCJ) and mixed ugarcane juice (MSCJ), as previously detailed in Fig. 1. The soluble olids parameter includes sugars and organic acids; Pol. refers to ucrose content in the solution. .2. Rheological properties Rheological measurements were carried out using an AR 2000 heometer (TA Instruments, New Castle, DE) with cone-and-plate eometry (60 mm disc, 4◦ angle) under controlled stress and tem- Fig. 1. Schematic representation of the unit operations involved in the processing of sugarcane juice before fermentation. perature. Shear rate range was 4–180 s−1 and both upward and downward tests were performed in triplicate for each temperature for every juice. The experimental procedure was previously tested on a rheological study of solutions of ethylene glycol and chloroben- zene [7]. Fitted rheological models for the dependence of shear rate on shear stress and for the dependence of the obtained rheologi- cal parameters on temperature and soluble solids were obtained by non-linear estimation procedure implemented in the software STA- TISTICA (Version 8.0, StatSoft, Inc., Tulsa, USA, 2007), by minimizing the sum of squared errors. The reliability of the equations was eval- uated by the number of parameters, coefficient of determination (R2) and analysis of residuals. 2.3. Pressure loss measurements The apparatus shown schematically in Fig. 2 consists of a heat transfer section, where sugarcane juice was heated or cooled by flowing through a large thermostatic bath, kept at constant tem- perature. The heat transfer test section was composed by a set of three horizontal copper circular tubes with internal diameters of 6.3 mm, 7.8 mm and 10.2 mm and thickness of 1.4 mm. The total length of the section was 3.1 m providing a maximum length-to- diameter ratio (L/D) of 492. Differential pressure transmitters were used to measure static pressure at five different positions along the equipment (620, 1240, 1860, 2480, and 3100 mm from the heated tube inlet). Sugarcane juice was pumped by a peripheral pump (KSB model P-500, Brazil) at temperatures between 313 K and 373.4 K and between 273 K and 310 K using a gear pump (KSB model Triglav, Brazil). The wall temperature of the tube was kept constant by a thermostatic bath of silicon oil (Marconi, Brazil), which was pumped by means of a centrifugal pump (KSB model C-1010, Brazil). A static mixer was placed at the end of the equip- ment to homogenize the sugarcane juice at final temperature (Tm). A HP data logger, an interface HP-IB and a PC running a data acqui- sition and control program written in IBASIC (Navcon Engineering Network, Fullerton, CA, USA, 2007) to monitor temperatures and pressures. Measurements were accomplished to 134 different con- ditions for laminar flow and 148 conditions for turbulent flow. After the adjustment of the desired flow rate, the differential pressure data were recorded (10 data at intervals of 5 min). 2.4. Theoretical models Non-Newtonians fluids do not present a direct proportionality between shear stress and shear rate. To describe their rheologi- cal behavior, different flow models are commonly used. One of the most frequently used is the Ostwald-de-Waele model, better known as the Power-Law model [16], given by Eq. (1): � = K�̇n (1) 262 Z. Astolfi-Filho et al. / Biochemical Engineering Journal 53 (2011) 260–265 F easu � I s n t � I s c l t v E � I s f b l t f I i � w i p i ig. 2. Schematic diagram of the experimental setup used in the pressure loss m P = pressure drop. n Eq. (1) � is the shear stress, �̇ is the shear rate, K is the con- istency index and n is the flow behavior index. In cases in which = 1, K changes to � and Eq. (1) becomes the Newtonian model of he viscosity, expressed in Eq. (2): = ��̇ (2) n this case, � is a constant of proportionality between the shear tress applied on the fluid and the corresponding shear rate. This onstant is the dynamic viscosity of the Newtonian fluid. The rheo- ogical parameters K, n and �, are influenced by water content and emperature. In order to quantify the effect of temperature on the iscosity of Newtonian fluids, an Arrhenius-type equation, given by q. (3), is frequently employed [17–19]. = A0 exp ( Ea RT ) (3) n this expression, A0 is an empirical constant, R is the ideal gas con- tant, T is the absolute temperature and Ea is the activation energy or flow. Ea represents the energy barrier that must be overcome efore the elementary flow process can occur. One important application of rheological parameters is to calcu- ate the pressure drop during flow, which is usually made through he friction factor, f [20]. The friction factor is defined as: = 2�w �v2 (4) n this expression, � is the fluid density, v is the average flow veloc- ty, and �w is the stress in the wall, given by: w = D�P 4L (5) here D is the tube diameter and �P is the pressure drop observed n a length L of the tube. For laminar flow, the friction factor can be obtained from a sim- le function of the generalized Reynolds number (Reg), which is dentical to the dimensionless form of the Hagen–Poiseuille equa- rements. T0 = initial temperature; Tw = wall temperature; Tm = final temperature; tion [21]: f = 16 Reg (6) Reg can be expressed as [21]: Reg = Dnv(2−n)� 8(n−1)K ( 4n 1 + 3n )n (7) Eqs. (6) and (7) can be used for both non-Newtonian and Newtonian fluids. For these last, indeed, K ≡ � and n = 1, so that the generalized Reynolds number Reg becomes the well-known expression Re = Dv�/�. Under turbulent flow conditions, the correlations to estimate the friction factor are semi-empirical. For Newtonian fluids flowing in rough pipes with Re > 4000, the Colebrook equation is commonly used (Eq. (8)). This is an empirical modification of the von Karman equation to include the effect of wall roughness [21]: 1√ f = −4 log ( ε/D 3.7 + 1.255 Re √ f ) (8) where ε/D is the relative roughness of the tube. Eq. (8) is derived from data obtained with Newtonian fluids, such as water or liquids containing low molar mass solutes, under turbulent conditions of flow, within tubes with varying values of roughness (ε) [21]. Foust et al. [22] proposed an empirical relation which approaches to Eq. (8), and has the advantage of being simpler, as it is explicit in f: f = 0.0460 Re0.2 (9) 3. Results and discussion 3.1. Rheological properties In order to get an accurate evaluation of the rheological char- acteristics of sugarcane juices, the densities (�) of UCSJ, MSCJ and CSCJ were previously evaluated [23]. Density values showed a linear Z. Astolfi-Filho et al. / Biochemical Engineering Journal 53 (2011) 260–265 263 200180160140120100806040200 0 100 200 300 400 500 600 700 800 900 1000 T ( K) 277.4 286.5 296.4 307.0 S h e a r S tr e s s ( m P a ) Shear Rate (s-1) 200180160140120100806040200 0 100 200 300 400 500 600 700 800 900 1000 T ( K) 277.4 286.5 296.4 307.0 S h e a r S tr e s s ( m P a ) a b d ± t R e � � � I r c c e 1 t ( t b s a fi v M T t Table 2 Average and standard deviation values for viscosity (�) of the studied sugarcane juices at different temperatures (considering three independent measurements for each juice at each temperature). T/K Viscosity (�) ×103/Pa s Average Standard deviation Untreated Sugarcane Juice (USCJ). SS = 19.1% 277.4 5.000 1.000 286.5 3.000 0.000 296.4 2.000 0.000 307.0 0.980 0.035 317.4 0.630 0.009 328.2 0.390 0.007 340.4 0.230 0.015 352.0 0.130 0.016 364.1 0.087 0.003 373.4 0.070 0.010 Mixed Sugarcane Juice (MSCJ). SS = 18.8% 277.4 4.670 0.577 286.5 2.670 0.577 296.4 2.000 0.000 307.0 0.880 0.009 317.4 0.520 0.011 328.2 0.330 0.015 340.4 0.190 0.008 352.0 0.120 0.002 364.1 0.075 0.001 373.4 0.055 0.002 Clarified Sugarcane Juice (CSCJ). SS = 18.2% 277.4 4.000 0.000 286.5 2.000 0.000 296.4 1.000 0.000 307.0 0.750 0.009 317.4 0.450 0.005 328.2 0.270 0.002 340.4 0.160 0.005 Shear Rate (s-1) Fig. 3. Rheograms obtained for USCJ and CSCJ at different temperatures. ependence on temperature and the mean experimental error was 30 kg/m3 at 277.4 K ≤ T ≤ 373.4 K. Eq. (10) for UCSJ presented to he experimental data with R2 = 0.910, Eq. (11) for MSCJ was fitted 2 = 0.937 and Eq. (12), for CSCJ, with R2 = 0.978. The mean absolute rror found for density determination was 0.6%. = 1297.7 − 0.390T (UCSJ) (10) = 1177.7 − 0.347T (MSJC) (11) = 1179.7 − 0.354T (CSJC) (12) n these equations, � is given in kg m−3 and T in K. Before the heological measurements, the accuracy of the viscometer was hecked by comparing the measured viscosity of ethylene gly- ol and chlorobenzene with data previously presented by Perry t al. [24]: the maximum relative error (Eq. (10)) observed was .82%, whereas the maximum standard deviation of experimen- al replicates was 3.90%. In the studied ranges of temperature 277.4–373.5 K) and soluble solids content (18.2–19.1 (w/w) %), he sugarcane juices showed Newtonian behavior, as indicated y the linear dependence of the shear stress on the shear rate hown in Fig. 3. The Ostwald-De Waele (Power Law) model was lso used, but the detected n value was equal to 1, further con- rming that the fluids behavior was Newtonian. The dynamic iscosities determined for the studied sugarcane juices (UCSJ, SCJ and CSCJ), measured in triplicate, are reported in Table 2. hese data show that the viscosity varied from 0.044 × 10−3 Pa s o 5.0 × 10−3 Pa s and, as expected, an increase in the tempera- 352.0 0.100 0.002 364.1 0.060 0.006 373.4 0.044 0.002 ture induces the reduction of the sugarcane juice viscosities, as occurs with some fruit juices [14,15,25]. The Newtonian behavior of sugarcane juice may be attributed to the low molar mass of the solutes. The found viscosity magnitudes are comparable to litera- ture values concerning sugar solutions and fruit juices with similar soluble solids contents. For example, considering sugar solutions with about 20 mass%, from 278 K to 361 K [10], viscosity values var- ied as follows: for sucrose, from 3.15 × 10−3 Pa s to 0.55 × 10−3 Pa s; for fructose, from 2.95 × 10−3 Pa s to 0.51 × 10−3 Pa s; for glucose, they lied in the range 3.11 × 10−3 Pa s to 0.54 × 10−3 Pa s. Consider- ing Josapine pineapple juice with about 14 mass% sucrose (◦Brix), from 278 K to 338 K [15], viscosity varied from 47 × 10−3 Pa s to 24 × 10−3 Pa s. Finally, according to Nindo et al. [26], for blue- berry juices with 20 ◦Brix, viscosities varies from 3 × 10−3 Pa s to 1 × 10−3 Pa s; for raspberry juices with the same ◦Brix, the values varied from 3.5 × 10−3 Pa s to 0.7 × 10−3 Pa s (293–333 K). The dynamic viscosity was also expressed as functions of tem- perature, using an Arrhenius-type model. The resulting functions are represented by Eqs. (13), (14) and (15), respectively, for USCJ, MSCJ and CSCJ. The model was able to adjust the experimental data with coefficient of determination (R2) above 0.990 in the three cases. Dynamic viscosities estimated by Eqs. (13)–(15) exhibited good agreement with the corresponding experimental values. � = 5.91 × 10−10 exp ( Ea RT ) , R2 = 0.998 (USCJ) (13) ( ) � = 4.65 × 10−10 exp Ea RT , R2 = 0.992 (MSCJ) (14) � = 0.14 × 10−10 exp ( Ea RT ) , R2 = 0.994 (CSCJ) (15) 264 Z. Astolfi-Filho et al. / Biochemical Engine 100001000100 0,01 0,1 1 Transition Flow Turbulent Flow Laminar Flow F ri c ti o n f a c to r Reynolds number 100001000100 0,01 0,1 USCJ USCJ CSCJ CSCJ Transition Flow Turbulent Flow Laminar Flow F ri c ti o n f a c to r Reynolds number a b F U E fl h t f 3 3 ( c P s w ( f F ( m ( f number. The good agreement between experimental values and ig. 4. Experimental friction factors obtained for (a) ethylene glycol and (b) for the SCJ and CSCJ sugarcane juices. qs. (13)–(15) are Arrhenius-type. So, the activation energies for ow (Ea) could be calculated. According to Holdsworth [27], the igher the value of activation energy, the larger is the effect of emperature on the considered property. The calculated values or Ea for the three studied fluids were: 36,796.5 J/mol for USCJ, 7,182.5 J/mol for MSCJ and 44,912.9 J/mol for the CSCJ. .2. Friction factors determination In order to evaluate the performance of the experimental setup Fig. 2) for pressure drop measurements, preliminary tests were onducted in the proposed system using the ethylene glycol flow. ipe dimensions, density values and measured pressure drop were ubstituted in Eqs. (4) and (5) to calculate the friction factor, f, which as then correlated with the Reynolds number calculated by Eq. 7), using the experimental rheological parameters K ≡ � and n = 1 or ethylene glycol [24,28]. The experimental results, presented in ig. 4a, display a good agreement with calculated values, using Eq. 6), for the laminar region, and Eq. (9), for turbulent region. Experimental friction factors for ethylene glycol were also sub- itted to nonlinear regression analysis, resulting in Eqs. (16) and 17) for laminar and turbulent flow, respectively. = 16.54 Re (16) ering Journal 53 (2011) 260–265 f = 0.0470 Re0.198 (17) Eq. (16) was adjusted in the range of 27.5 < Re < 2086.3 with R2 = 0.994, and the obtained parameters were similar to the the- oretical values present in Eq. (6). Taking into account the turbulent region, where 4132.1 < Re < 62,232, Eq. (17) was adjusted with R2 = 0.908. The R2 values obtained in the present work exhibit the same order of magnitude of those determined by using Eq. (9) [22], confirming the suitability of the experimental apparatus. Tube flow experiments were also carried out during heating of sugarcane juices and the experimental pressure loss data have been used to calculate the friction factor, according to Eqs. (4) and (5). Densities were evaluated at the average temperature between the initial and the final conditions attained by the sugarcane juice during flow, using Eqs. (10), (11) and (12). The data on the ther- mophysical properties (thermal conductivity, heat capacity and density) for USCJ, CSCJ and MSCJ were reported elsewhere [23]. The experimental friction factors measured for USCJ and CSCJ in conditions of Newtonian behavior are shown in Fig. 4b. Eq. (18) was adjusted in the laminar region (41.4 < Re < 1882.6) for both sugar juices; the obtained parameters were satisfactory well adjusted with R2 = 0.969. In the turbulent region (4301.5 < Re < 61878) the resulting Eq. (19) was obtained with R2 = 0.878. f = 17.12 Re (18) f = 0.0475 Re0.197 (19) A comparison between the friction factors during laminar flow of Newtonian fluids in circular pipes and the Reynolds number with the analytical solution tend to slightly overestimate the friction fac- tor of the sugarcane juices. According to Steffe and Singh [29], this may be due to wall slip or time dependent changes in rheological properties that can occur in suspension and emulsion type prod- ucts. For higher Reynolds numbers, the experimental data were compared with those predicted by the correlation showed by Eq. (9), resulting in a good agreement. The average relative error was of 5.77% with a maximum of 9.06%. It is worthy to mention that data presented in Fig. 4b may be considered of limited importance, because they only confirm the suitability of already widely accepted correlations for predicting friction factors, such as the theoretical equations (6) and (9). On the other hand, the good agreement observed between friction fac- tors calculated from experimental data on pressure loss and those estimated from the measured rheological parameters supports the reliability of the models obtained for describing the rheological properties of untreated (USCJ), clarified (CSCJ) and mixed (MSCJ) sugarcane juices (Eqs. (13)–(15)). 4. Summary and conclusions Sugarcane juice constitutes one of the most important resources for ethanol fuel production. In this study, the rheological behavior of untreated (USCJ), clarified (CSCJ) and mixed (MSCJ) sugar- cane juices was investigated. At temperature range of 277–333 K, they were found to exhibit a Newtonian behavior in flow, with the viscosity values lowering as the temperature was increased. The Newtonian model satisfactorily fitted the experimental flow curves. Friction factors, measured in both laminar and turbulent flows, were found to be well correlated in terms of the Reynolds values predicted by theoretical equations confirmed the reliability of the proposed equations in describing the rheological properties of the evaluated sugarcane juices. Therefore, the outlined rheologi- cal and flow dynamics data, in the considered temperature interval, Engin s p t A S f o R [ [ [ [ [ [ [ [ [ [ [ [ [ [ [ [ [ [ [28] M.A. Polizelli, F.C. Manegalli, V.R.N. Telis, J. Telis-Romero, Friction losses in Z. Astolfi-Filho et al. / Biochemical eem to be reliable to be used in optimization of unit operations and rocesses involving these sugarcane juices in the ethanol produc- ion. cknowledgments The authors wish to thank the financial support from São Paulo tate Research Fund Agency (FAPESP/Brazil, 2002/02461-0) and rom the National Council of Technological and Scientific Devel- pment (CNPq/Brazil). eferences [1] V.A. Amalraj, P. Rakkiyappan, D. Neelamathi, S. Chinnaraj, S. Subramanian, Wild cane as a renewable source for fuel and fibre in the paper industry, Current Science 95 (2008) 1599–1602. [2] K.K. Cheng, B.Y. Cai, J.A. Zhang, H.Z. Ling, Y.J. Zhoua, J.P. Geb, J.M. Xua, Sugarcane bagasse hemicellulose hydrolysate for ethanol production by acid recovery process, Biochemical Engineering Journal 38 (2008) 105–109. [3] C.A. Cardona, O.J. Sanchez, Fuel ethanol production: process design and trends and integration opportunities, Bioresource Technology 98 (2007) 2415–2457. [4] J.R. Moreira, Sugar cane for energy: recent results and progress in Brazil, Energy for Sustainable Development 17 (2000) 43–54. [5] I. Seyssiecq, J.H. Ferrasse, N. Roche, State-of-the-art: rheological characteri- zation of wastewater treatment sludge, Biochemical Engineering Journal 16 (2003) 41–56. [6] A. Peverea, G. Guibauda, E. Goina, E. van Hullebuscha, P. Lensb, Effects of physico-chemical factors on the viscosity evolution of anaerobic granular sludge, Biochemical Engineering Journal 43 (2009) 231–238. [7] M.I. Berto, A.C.A. Gratão, A.A. Vitali, V. Silveira Junior, Rheology of sucrose-CMC model solution, Journal of Texture Studies 34 (2003) 391–400. [8] M. Quintas, T.R.S. Brandão, C.L.M. Silva, R.L. Cunha, Rheology of supersaturated sucrose solutions, Journal of Food Engineering 77 (2006) 844–852. [9] H.M. El-Mashad, W.K.P. van Loon, G. Zeeman, G.P.A. Bot, Rheological properties of dairy cattle manure, Bioresource Technology 96 (2005) 531–535. 10] V.R.N. Telis, J. Telis-Romero, H.B. Mazzoti, A.L. Gabas, Viscosity of aqueous carbohydrate solutions at different temperatures and concentrations, Inter- national Journal of Food Properties 10 (2007) 185–195. 11] S.N. Guerrero, S.M. Alzamora, Effect of pH, temperature and glucose addition on flow behaviour of fruits purées: II. peach, papaya and mango purées, Journal of Food Engineering 37 (1998) 77–101. 12] J. Telis-Romero, R.A. Cabral, A.L. Gabas, V.R.N. Telis, Rheological properties and fluid dynamics of coffee extract, Journal of Food Process and Engineering 24 (2001) 217–230. [ eering Journal 53 (2011) 260–265 265 13] P.A. Sopade, P.J. Halley, B. D’Arcy, B. Bhandari, N. Caffin, Friction factors and rhe- ological behaviour of Australian honey in a straight pipe, International Journal of Food Properties 7 (2004) 393–405. 14] K.B. Belibagli, A.C. Dalgic, Rheological properties of sourcherry juice and concentrate, Journal of Food Science and Technology 42 (2007) 773– 776. 15] R. Shamsudin, W.R.W. Daud, M.S. Takrif, O. Hassan, C. Ilicali, Rheologi- cal properties of Josapine pineapple juice at different stages of maturity, International Journal of Food Science & Technology 44 (2009) 757– 762. 16] M.A. Rao, Rheology of Fluids and Semisolids: Principles and Applications, An Publishers, Inc., Gaitherburg, Maryland, 1999. 17] B.B. Gunjal, N.J. Waghmare, Flow characteristics of pulp juice and nectar of baneshan and neelum mangoes, Journal of Food Science and Technology 24 (1987) 20–23. 18] J. Telis-Romero, V.R.N. Telis, F. Yamashita, Friction factors and rheological prop- erties of orange juice, Journal of Food Engineering 40 (1999) 101–106. 19] A.C.A. Gratão, V. Silveira Junior, J.T. Romero, Laminar flow of soursop juice through concentric annuli: friction factors and rheology, Journal of Food Engi- neering 78 (2007) 1343–1354. 20] E.J. Garcia, J.F. Steffe, Comparison of friction factor equations for non- Newtonian fluids in pipe flow, Journal of Food Process and Engineering 9 (1987) 93–120. 21] R. Derby, Chemical Engineering Fluid Mechanics, Marcel Dekker, New York, 1996. 22] A.S. Foust, L.A. Wenzel, C.W. Clump, L. Maus, L.B. Andersen, Principles of Unit Operations, 2nd ed., John Willey & Sons, 1980. 23] Z. Altolfi-Filho, L.A. Minim, J. Telis-Romero, V.P.R. Minim, V.R.N. Telis, Ther- mophysical properties of industrial sugarcane juices for the production of bioethanol, Journal of Chemical and Engineering Data 55 (2010) 1200– 1203. 24] R.H. Perry, C.H. Chilton, D.W. Green, Chemical Engineers’ Handbook, 2nd ed., McGraw-Hill Education (ISE Editions), 1985. 25] N.I. Singh, W.E. Eipeson, Rheological behaviour of clarified mango juice con- centrates, Journal of Texture Studies 31 (2000) 287–295. 26] C.I. Nindo, J. Tang, J.R. Powers, P. Singh, Viscosity of blueberry and rasp- berry juices for processing applications, Journal of Food Engineering 69 (2005) 343–350. 27] S.D. Holdsworth, Applicability of rheological models to the interpretation of flow and processing behaviour of fluid food products, Journal of Texture Studies 2 (1971) 393–418. valves and fittings for Power-Law fluids, Brazilian Journal of Chemical Engi- neering 20 (2003) 455–463. 29] J.F. Steffe, R.P. Singh, Pipeline design calculations for Newtonian and non- Newtonian fluids, in: K.J. Valentas, E. Rotstein, R.P. Singh (Eds.), Handbook of Food Enegineering Practice, CRC Press, Boca Raton, 1997. Rheology and fluid dynamics properties of sugarcane juice Introduction Materials and methods Sugarcane juice composition Rheological properties Pressure loss measurements Theoretical models Results and discussion Rheological properties Friction factors determination Summary and conclusions Acknowledgments References