alcohol withdrawal scale BIBLIOGRAPHY 1. ORTHOEFER, F. T. "Rice Bran Oil". Bailey Industrial Oil and Fat Products. John Wiley & Sons, 2005 2. GANDRA, K.M. "Obtention and characterization of wax sugar cane and fractions". Brazil, 2006 3. STRANSKY, K .; ZAREVUCKA, M .; VALTEROV, M .; WIMMER, Z. "Gas chromatographic retention data of wax esters". Journal of Chromatography A. no. 1128, p. 208-219, 2006. 4. DUTRA, L. J. "Simplified process for the production of cadeia longa grax acid acids (D-003) from sugar cane wax (Saccharum officinarum L.)". Brazil, 2010. 5. WOHLFAHRT, L .; SACHSE, J. "Method for obtaining waxes of cachaça". Patent CU 22282 A3, Cuba, 1995. 6. DÍAZ, Loida; GUERRERO, Lázaro; HIDALGO, Antonio; Villanueva, Gretel; RODRIGUEZ, Elina. "Influence of different variables in the extraction of crude wax". Sugar Center no. 3, p. 59-62, 2000. 7. DÍAZ, Loida; GUERRERO, Lázaro; Villanueva, Gretel. "Influence of the temperature of heptane in the extraction of fractions of crude wax". Sugar Center no. 4, p. 29-31, 2000. 8. GARCÍA, Alberto; GARCÍA, Miguel A .; RIBAS, Mauricio; BROWN, Adolfo. "Recovery of sugarcane cuticle wax by mechanical separation and extraction with solvents". Fats and oils., Vol 54, p. 169-174, 2003. 9. LÓPEZ-MESA, M .; CARRILLO, F .; GUTIÉRREZ, M. C .; CRESPI, M. "Alternative methods for the wool wax extraction from wool scouring wastes". Fats and oils, vol 58, p. 4, 2007. 10. ATHUKORALA, Y .; MAZZA, G. "Supercritical carbon dioxide and hexane extraction of wax from triticale straw: Content, composition and thermal properties". Industrial Crops and Products., Vol 31, p. 550-556. 2010 11. GARCÍA, Romel. Assimilation of a technology to obtain biodiesel from waste in the sugar industry. "Central University Martha Abreu de las Villas, 2011. 12. ROSS, F.B. Ross Waxes. 10th Edition. Jersey City. 1987 13. PETERS, M., TIMMERHAUS, K., Plant design and economics for chemical engineers. 4th ed. USA, McGraw-hill International Editions. 1990. 14. ZHANG, Y .; KATES, M. "Biodiesel production from waste cooking oil". p. 1-16 2003 15. BHOSALE, P. R .; CHONDE, G .; RAUT, P. D. "Studies on extraction of sugarcane wax from press mud of sugar factories from Kolhapurdistrict, Maharashtra". Journal of Environmental Research and Development, vol 6, no. 3A, p. 715-720, 2012.

Extraction of wax from filter cake with 96 ° GL ethanol at laboratory scale



Wax extraction from filter Cake with Ethanol 96 ° GL at Laboratory Scale





MSc. Inés María San Anastacio-RebollarI, Eng. Danilo Ricardo-GarcíaII, Eng. Rubén Carlos Hernández-GonzálezIII, Eng. Luis Eduardo Guerra-RodríguezIV, Dr. Gretel Villanueva-RamosV

I: Department of Chemistry, University "Ignacio Agramonte Loynaz", Camagüey, Cuba. ines.sananastacio@reduc.edu.cu
II: Basic State Unit "Antonio Guiteras", Camagüey
III: MININT Delegation, Camagüey
IV: Industrial Department, "Ignacio Agramonte Loynaz" University, Camagüey, Cuba
V: Chemical Engineering Department, Central University of Las Villas, "Martha Abreu", Cuba





Summary

In this article, we propose a methodology for the production of wax from the sugarcane cachaça, in which substances that are aggressive to the environment are not used. The wax is extracted from the cachaça, a residue of the sugar industry, using as solvent ethanol (with a purity of 96 º GL). The extraction of wax was carried out by a leaching process using a cachaza / ethanol ratio of 0.05 kg / L. the operating parameters defined were: temperature of 70 ºC, atmospheric pressure, agitation speed of 700 rpm and extraction time of 2.5 hours. Under these conditions 86.17% extraction was obtained. The obtained wax presented the necessary characteristics to compete in the vegetable wax market. To evaluate the feasibility of designing a demonstration plant for wax production, a simulation of the entire process was carried out with the professional simulation software "Super Pro Design". For this simulation, results obtained in the laboratory were used.

Keywords: wax, extraction, cachaça.

Abstract

This article proposes a methodology for the production of wax starting from the sugar cane phlegm, in which aggressive substances to the environment are not used. The wax is extracted from the phlegm, a residue of the sugar industry, by using ethanol (with a purity of 96 º GL) as a solvent. A methodology to achieve the extraction of wax from the filter cake was determined. A filter cake: ethanol ratio, where for every 0.05 kg of filter cake: 1 L of ethanol was used. The operation parameters of temperature of 70 ºC, atmospheric pressure, speed of agitation 700 rpm and extraction time 2,5 hour were defined. Under the above mentioned conditions 86,17% of extraction was achieved. The obtained wax presented the necessary characteristics to compete in the market of vegetable wax. In order to evaluate the feasibility of a demonstration plant for wax production, a simulation of the complete process with the professional simulation software (Super Pro Design) was performed. Laboratory obtained results were used for this simulation.

Keywords: wax, extraction, filter cake.





INTRODUCTION

Sugar, for several years, has been facing a very critical situation as a product of international marketing, so it has been the interest of the sugarcane producing countries, the development of a strategy to increase the competitiveness of the sugar industry, which has included as a fundamental action the diversification of the same, through the integral use of sugarcane as a raw material for a large number of derivatives and by-products.

The main residues of the sugar industry are bagasse, vinazas and cachaça. The bagasse and vinasse find applications in other industries or processes, however, the cachaça, is used primarily as an additive in animal feed and fertilizer in agriculture. Said use is limited by the capacity of the soils to accept it, which causes serious contamination problems. For these reasons, it is necessary to find a large-scale solution for the revaluation of this waste.Due to its chemical composition and low price, the cachaça is very attractive as a raw material in the process industry, which is why it is one of the byproducts with the best prospects for industrial use. From it you can extract wax, which contains 35.5% saponifiable matter (fatty acids) and 60% unsaponifiable matter, products of great industrial interest, due to the wide range of applications of its components [1].

The raw sugar cane wax is dark in color and waxy in texture. It is composed of 45% wax, 35% fat and 20% resin. Refined wax contains 55% esters; 8% free acids; 10% free alcohols; 25% aldehydes and ketones and 2% hydrocarbons [2]. The wax obtained from sugarcane can also be defined as a chemical combination of several metabolites that have been identified by means of gas chromatography [3] and HPLC chromatography [4].

The objective of this article is to propose a methodology for the production of wax from the cane sugarcane, in which substances that are aggressive to the environment are not used.

Since the beginning of the 20th century, the process of extracting wax from the cachaça began to attract attention. In 1916, the English firm Rose Dows and Thomson, proposed the process of Merz, which consists of the successive extraction of the oily fraction and hard wax present in the cachaça. To extract the fat fraction, n-heptane is used between 15-20 ºC. Subsequently, the solvent is heated to 105 ° C to extract the hard wax fraction. The advantage of this process is that the same solvent is used in the extraction of both fractions and its disadvantage is the drying of the filter cake.

Later, in 1940 Swenson patented a process for the extraction of the raw wax contained in the wet cachaça using a column of perforated plates. In it, a series of arms attached to a central axis produce agitation inside the column. A stream of n-heptane at 100-110 ° C enters the bottom, flows upwards and exits the top of the column in the form of a wax solution in n-heptane. Then it goes to a recovery system. The disadvantage of the method lies in the contact scheme, because water hinders extraction.

Years later, in 1995, Wohlfahrt L et al. They presented a procedure for the industrial obtaining and refining of wax from the dry cachaça. They performed the extraction in a percolation extractor, using saturated aliphatic hydrocarbon solvents such as n-hexane and n-heptane. The process is carried out at a temperature lower than the boiling temperature of the solvent, maintaining a mass ratio of 1: 5 (cachaza: solvent). Wax fractions are precipitated by stepwise cooling of the extract and the solvent with residues is recirculated to the process [5].

More recently, Díaz et al. determined the main operating variables for the industrial production of wax using n-heptane as a solvent [6]. Of all these parameters, as the process is a liquid-liquid extraction, the temperature was the most important and its value should be as close as possible to the boiling temperature of the solvent, since the same, the equilibrium speed is higher and there is a greater extraction [7].

Subsequently, other authors evaluated the extraction of wax from the cuticle of the cane for the production of wax, especially directed to the pharmaceutical sector. They analyzed the use of three classes of organic solvents: petroleum ether, trichlorethylene and toluene, reaching an extraction efficiency of 4.71%, 4.18% and 3.73% respectively. They characterized the wax extracted technically by the physico-chemical indexes and by gas chromatography, showing that the wax with the highest hardness was the one obtained with toluene, which is the solvent with the highest boiling point [8].

Recently, supercritical fluid of carbon dioxide and n-hexane was used as a solvent at 70 ° C and a flow of 50 g / min at different pressures (250, 300, 350 and 400 bar). The authors verified that the wax extracted by this method presents a greater stability to oxidation than that extracted by means of Soxhlet. [9, 10]. García, in 2011, in a process to obtain biodiesel, proposes the extraction of wax by lixiviation of the filter cake with ethanol 96 ° GL for four hours, reporting 94.92% extraction, determined by weight difference [11]. The extraction time represents the main drawback of this proposal. However, although new techniques have been developed for the extraction of wax, they are still used at an industrial level, solvents that cause serious damage to the environment.USED ​​METHODS AND EXPERIMENTAL CONDITIONS

Characteristics of the cachaça

We worked with cachaza from the UEB Antonio Guiteras, from the province of Las Tunas, Cuba. The humidity and the wax content in it were determined. The humidity was determined by drying in an oven until constant weight. For its part, the wax content was obtained by the Soxhlet method.

For the quantification of the wax content, the ultraviolet (UV) spectrum of a wax solution in ethanol was first performed. Then the calibration curve was made using as standard raw wax produced in the UEB Antonio Guiteras. A standard solution of wax in ethanol of 8.75x10-2 g / mL concentration was prepared. Solutions of concentrations 1.25x10-3, 2.5x10-3, 3.75x10-3, 5x10-3 were prepared from this solution. , 6.25x10-3 and 7.5x10-3 g / mL and its absorbance at 205 nm was read.

Extraction stage

Design of experiments

A design of factorial screening experiments 22 was carried out to analyze the influence of temperature and time in the extraction. Once the independent variables are established, the study interval of each one is selected. Regarding the extraction time, García proposed the leaching of the filter cake for four hours with ethanol 96 ºGL [11], therefore, this value is assigned to the upper level. As a lower level, for a first approximation, two hours are taken, evaluating the reduction by half the extraction time. Regarding the temperature, 70 oC is selected as the maximum level, to avoid the extraction of the heaviest fractions and 65 oC as the minimum value, so that the operating temperature does not move away from the boiling point of the solvent, since there is a greater speed of balance and extraction. The percentage of extraction was selected as a response variable.

Table 1 shows the experimental runs defined by the design. Five replicates of each run established in the design of experiments were made. In each one, 96 ° GL ethanol and ethanol were mixed in a proportion of 0.05 kg of filter cake per liter of ethanol, at atmospheric pressure and stirring at 700 rpm, at the temperature and for the corresponding time in each case. The experimental results were processed through the statistical program Statgraphics Centurion.

Table 1
Design of experiments

Running number

t (h)

T (° C)

1

4

65

2

2

70

3

2

65

4

4

70

Kinetics of the extraction operation

To study the kinetics of the extraction, the wax content in the extract was determined every 30 min. The results were analyzed using the Statgraphics Centurion software.

Extraction stage

The 96 ° GL ethanol and filter cake were mixed in a proportion of 0.05 kg of filter cake per liter of ethanol in a two liter capacity cylindrical vessel, with an effective volume of 1425 mL, at a temperature of 70 ° C, atmospheric pressure, stirring at 700 rpm for 2.5 h. After the extraction, the filter cake was separated by vacuum filtration and through a mesh of holes of 75 μm in diameter. The amount of ethanol in the exhausted filter cake was determined by drying to constant weight. The solvent of the extract was evaporated to obtain the wax.

Characteristics of the extracted wax

The acidity index (IA), the saponification index (IS) and the iodine index (II) according to the rules of A.S.T.M. reported for vegetable waxes [12]. Also, the melting temperature was determined in a WRS-2A microplate.

Simulation and process design

To evaluate the possible design of a demonstration plant for the proposed process, the complete continuous process of extraction of wax from the filter cake with ethanol 96 ºGL was designed and simulated. For this research, the Super Pro Designer process simulation software was used, since this software can provide reliable information about the process. Once the capacity of the plant was fixed, the procedures for the simulation of the process required the definition of the stages and the determination of the material and energy balances. The calculation of economic parameters and indicators was carried out following the methodology established by Peters [13].

Due to the presence of ethanol, a very polar component, thermodynamic activity models NRTL and UNIQUAC are used to predict the coefficients of activity of components in a liquid phase [14]. In this study the NRTL model was used.RESULTS AND DISCUSSION

Characteristics of the cachaça

The humidity determination of the sample of cachaça showed an average value of 7.82%. On the other hand, the UV spectrum of the wax (Figure 1) showed an absorption band between 200 and 240 nm, with a maximum at 205 nm. This band is due to the presence of the carbonyl group substituted by a heteroatom or group with free electrons, in this case oxygen, which produces a marked hypsochromic shift nπ *. The presence of this absorption maximum shows that it is possible to determine wax at a wavelength of 205 nm by UV spectrophotometry. The calibration curve was made with a correlation coefficient of 0.993 1 and the wax content in the filter cake was determined to be 9.92% b.s.



Fig. 1 UV spectrum of a crude wax solution in ethanol.

Extraction stage

Experiment design

Table 2 shows the percentage of wax extracted in each of the experiments carried out. Figure 2 represents the Pareto diagram that reflects the influence of the variables and their interaction on the percentage of extraction.

Table 2
Experimental results of extraction

Run

X1

X2

Performance (%)

1

4

65

5.66

5.51

5.75

5.73

5.58

2

2

70

7.66

7.41

7.55

7.71

7.49

3

2

65

5.16

4.83

5.48

5.1

5.18

4

4

70

6.16

6.36

6.39

6.24

6.31



Fig. 2 Pareto diagram of the experimental design.

The diagram shows that both the independent variables (time and temperature) and their interaction significantly influence the extraction performance in the studied interval. However, only the temperature has a positive influence. As also observed in the table, the highest extraction yields were obtained when the operation was carried out for two hours at 70 ° C. This indicates that, of the levels studied for each variable, at 70 ° C and two hours the highest performance in the operation is achieved.

Kinetics of the extraction operation

The previous design of experiments allowed to assign a value to the variables (time and temperature), within the studied interval, to achieve the highest percentage of extraction. With a view to expanding the investigative framework on the time variable, the kinetic study of the extraction operation at 70 ° C was carried out.

Table 3 shows the extraction results obtained at different times, which are represented in figure 3. The statistical analysis of these results showed that there are no significant differences, for a confidence level of 95%, between the different experimental runs made.Table 3
Variation in the concentration of extractables over time during extraction

Time (h)

Concentration (mg / mL)

Replica 1

Replica 2

Replica 3

Reply 4

Replica 5

0.5

2.43

2.43

2.45

2,44

2.46

1

2.68

2.80

2.68

2.68

2.69

1,5

2.78

2.80

2.80

2.79

2.81

2

3.30

3.21

3.35

3.31

3.32

2.5

3.49

3.48

3.50

3.50

3.50

3

3.54

3.59

3.54

3.53

3.53

3.5

3.53

3.53

3.52

3.52

3.52

4

3.52

3.53

3.53

3.53

3.55

4.5

3.53

3.52

3.53

3.52

3.53



Fig. 3 Variation in the concentration of extractables over time.

It was observed that the amount of wax extracted from three hours remained practically constant, with a value of 3.54 g for 85.4% extraction. However, a multi-rank test using the Student-Newman-Keuls method, with 99% confidence, showed, starting from 2.5 h of extraction, the compared values ​​do not show statistically significant differences. Therefore, 2.5 h were selected as the extraction time.

Extraction in a stage

The extraction process was studied in one stage. Table 4 shows the performance of the wax extraction for the ten experiments carried out. The statistical analysis according to the Chi-square and Shapiro-Wilk W. tests revealed that the results obtained followed a normal distribution for 95% confidence, since the probability value was 0.96 and 0.99 respectively. The mean performance of the wax extraction was 7.56%, which represented 86.17% extraction. This percentage is lower than the 94.92% reported by García [11]. This author determined the extractables by weight difference between the initial cachaça and the exhausted cachaça, in such a way, all the substances extracted by the solvent were quantified. However, in the present work, the number of substances quantified as extractables was reduced, taking into account only those that contained the carbonyl group in their structure.

The extraction performance in a stage of 86.17% was achieved under the following conditions: cachaza ratio: ethanol 96 ºGL of 0.05 kg / L, temperature of 70 ºC, atmospheric pressure, agitation of 700 rpm and time of 2, 5 h. It should be noted that this time represents practically half of that proposed by García (four hours) [11].

Table 4
Extraction performanceExp.

1

2

3

4

5

6

7

8

9

10

Rend. (%)

7.42

7.35

7.68

7.60

7.55

7.49

7.58

7.78

7.55

7.64

By means of vacuum filtering and the mesh of holes of 75 μm in diameter, methods used for the separation of exhausted filter cake from the extract were obtained a loss of ethanol in the spent filter cake of 147 mL (13.74%) and 172 mL ( 16.07%) respectively. Consequently, the use of the mesh increased the losses of ethanol in the filter cake by 2.33%, a relatively small value compared with the simplicity of the process with respect to vacuum filtration.

Characteristics of the extracted wax

The wax obtained was green. Its melting temperature was in the range between 81.3-87.1 ° C. The value of the IA, IS and II of the same was of 31.42%, 90.3% and 24.44% respectively. These three parameters are used to establish the quality of the wax [15]. The AI ​​reflects its degree of contamination, the older it is the more contaminated it is. The II measures the amount of unsaturated fatty acids present, indicating the facility to oxidize and the drying power of the wax, so the lower it is, the higher quality it has. For its part, the IS is required to be high, this represents the number of acid groups and esters. Its difference with the AI ​​is a measure of the amount of esters (wax) present. It is a particularly important parameter for users of rusted waxes.

The value of these quality indices is in the range reported for commercial waxes of plant origin [15]. This allows to state that the wax obtained can compete in the vegetable wax market.

Simulation and process design

The capacity of the plant was taken as reported by García [11] of 2 t / d (250 kg / h) of cachaça; the conditions of extraction of wax were: ratio cachaza: ethanol 96 º GL of 0,05 kg / L, temperature of 70 ºC, atmospheric pressure, agitation of 700 rpm and time of extraction of 2,5 h. Under these conditions, 86.17% of the extraction yield of wax was obtained, in one stage.

In the flow chart of figure 4, the use of two extractors is proposed, because this is the slowest stage of the process (2.5 h); in this way, the work of the extractors in an outdated manner, allows three productions to be made in an eight-hour day. These extractors are used at the same time as mechanical separators, placing a mesh in the bottom, with the aim of achieving solid-liquid separation, thus contributing to the use of a smaller number of equipment.



Fig. 4 Flow diagram for the production of wax from filter cake.

Nomenclature of the flow diagram:

1. Ethanol storage tank

2. Extraction tank

3. Condenser

4. Tank storage extract

5. Evaporator

6. Condenser

E-ethanol 96 ºGL
C- cachaza
Cachachaza exhausted
Ex- extract
Recovered ethanol
Cerara

From this process, only one waste stream is generated, the exhausted filter cake, from which it is proposed to recover the ethanol by evaporation, to be reused in the process. Then this residual cachaça can be used as an agricultural fertilizer [11].

Through an economic analysis, the extraction process carried out was compared to the times of two, 2.5 and three hours. The values ​​of the dynamic economic indicators appear in table 5. They show that extraction for two hours is less economically feasible than at 2.5 and three hours, with its PRI 4.96 times higher and its NPV and IRR 19.79 and ten times lower respectively than in the extraction at 2.5 and three hours.

In addition, it is observed that the values ​​of the economic indicators of the extraction during three hours are similar to those obtained at 2.5 h, thus not reporting a greater economic benefit, for which purpose it does not fulfill the objective. These results coincide with that obtained in the multi-rank test using the Student-Newman-Keuls method with a 99% confidence previously presented and corroborates the selection of 2.5 h as extraction time.

Table 5
Economic indicators for extraction at different times

Indicator

Time (hours)

2

2.5

3

PRI (years)

7.05

1.42

1.42

VAN (USD)

75 913.41

1 502 147.4

1 501 545.8

TRI (%)

7

70

70



CONCLUSIONS

1. A methodology is proposed to obtain wax from cachaça in which no aggressive solvents are used to the environment. In the same, the wax was obtained under the following conditions: ratio cachaza: ethanol 96 ºGL of 0.05 kg / L, temperature of 70 ºC, atmospheric pressure, agitation of 700 rpm and extraction time of 2.5 hours. Under these conditions, the extraction yield was 86.17%.

2. The methodology proposed to produce wax, from sugar cane cachaça, proved to be economically feasible and environmentally compatible.BIBLIOGRAPHY

1. ORTHOEFER, F. T. "Rice Bran Oil". Bailey Industrial Oil and Fat Products. John Wiley & Sons, 2005

2. GANDRA, K.M. "Obtention and characterization of wax sugar cane and fractions". Brazil, 2006

3. STRANSKY, K .; ZAREVUCKA, M .; VALTEROV, M .; WIMMER, Z. "Gas chromatographic retention data of wax esters". Journal of Chromatography A. no. 1128, p. 208-219, 2006.

4. DUTRA, L. J. "Simplified process for the production of cadeia longa grax acid acids (D-003) from sugar cane wax (Saccharum officinarum L.)". Brazil, 2010.

5. WOHLFAHRT, L .; SACHSE, J. "Method for obtaining waxes of cachaça". Patent CU 22282 A3, Cuba, 1995.

6. DÍAZ, Loida; GUERRERO, Lázaro; HIDALGO, Antonio; Villanueva, Gretel; RODRIGUEZ, Elina. "Influence of different variables in the extraction of crude wax". Sugar Center no. 3, p. 59-62, 2000.

7. DÍAZ, Loida; GUERRERO, Lázaro; Villanueva, Gretel. "Influence of the temperature of heptane in the extraction of fractions of crude wax". Sugar Center no. 4, p. 29-31, 2000.

8. GARCÍA, Alberto; GARCÍA, Miguel A .; RIBAS, Mauricio; BROWN, Adolfo. "Recovery of sugarcane cuticle wax by mechanical separation and extraction with solvents". Fats and oils., Vol 54, p. 169-174, 2003.

9. LÓPEZ-MESA, M .; CARRILLO, F .; GUTIÉRREZ, M. C .; CRESPI, M. "Alternative methods for the wool wax extraction from wool scouring wastes". Fats and oils, vol 58, p. 4, 2007.

10. ATHUKORALA, Y .; MAZZA, G. "Supercritical carbon dioxide and hexane extraction of wax from triticale straw: Content, composition and thermal properties". Industrial Crops and Products., Vol 31, p. 550-556. 2010

11. GARCÍA, Romel. Assimilation of a technology to obtain biodiesel from waste in the sugar industry. "Central University Martha Abreu de las Villas, 2011.

12. ROSS, F.B. Ross Waxes. 10th Edition. Jersey City. 1987

13. PETERS, M., TIMMERHAUS, K., Plant design and economics for chemical engineers. 4th ed. USA, McGraw-hill International Editions. 1990.

14. ZHANG, Y .; KATES, M. "Biodiesel production from waste cooking oil". p. 1-16 2003

15. BHOSALE, P. R .; CHONDE, G .; RAUT, P. D. "Studies on extraction of sugarcane wax from press mud of sugar factories from Kolhapurdistrict, Maharashtra". Journal of Environmental Research and Development, vol 6, no. 3A, p. 715-720, 2012.