Biodiesel production from one-step heterogeneous ...

Journal of Molecular Liquids 234 (2017) 157–163

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Journal of Molecular Liquids journal homepage: www.elsevier.com/locate/molliq

Biodiesel production from one-step heterogeneous catalyzed process of Castor oil and Jatropha oil using novel sulphonated phenyl silane montmorillonite catalyst Nabel A. Negm a,⁎, Galal H. Sayed b, Fatma Z. Yehia a, Onsy I. Habib a, Eslam A. Mohamed a a b

Petrochemicals Department, Egyptian Petroleum Research Institute, Nasr City, Cairo, Egypt Chemistry Department, Faculty of Science, Ain Shams University, Egypt

a r t i c l e

i n f o

Article history: Received 16 February 2017 Received in revised form 7 March 2017 Accepted 11 March 2017 Available online 15 March 2017 Keywords: Biodiesel Transesterification One-step process Heterogeneous catalyst Montmorillonite

a b s t r a c t The present study describes the preparation of novel modified montmorillonite clay in highly acidic form and its evaluation as a heterogeneous catalyst in the production of biodiesel from castor oil and jatropha oil by a one-step catalyzed transesterification reaction. The prepared catalyst was characterized by XRD, FT-IR, BET surface area and HRTEM. The study showed that the optimized conditions of castor oil transesterification were: 5% catalyst by weight, 1:12 oil to methanol molar ratio, at 60 °C for 300 min at 800 rpm; in case of jatropha oil: 5% catalyst by weight, 1:6 oil to methanol ratio, at 110 °C for 150 min at 800 rpm. The obtained biodiesels properties were agreed with the ASTM standard specifications. Blending of castor oil and jatropha oil biodiesels with petroleum diesel improved their fuel properties according to engine test parameters. The prepared catalyst exhibited highest activity in the transesterification reactions, and showed good stability during the reaction with a reusability for seven rounds of transesterification without considerable decrease in its activity. © 2017 Elsevier B.V. All rights reserved.

1. Introduction The depletion of petroleum sources has created interest in renewable energy sources. The world attention was directed to substitute diesel by biodiesel with no requirements for mechanical modification of engines [1]. Biodiesel is a mixture of methyl esters of different fatty acids and is produced from chemical modification of edible or non-edible oils [2–7], waste oils of domestic or industrial uses [8], fats from animals [9–11], algal or fungal fats. Vegetable oils including edible or nonedible oils are talented resources to produce biodiesel due to these oils are sustainable, renewable, have high mass production and have no negative impact on the environment [12–13]. The interference between depletion of human food resources in developing countries and biodiesel production from edible oils in addition to the increase of deforesting directed the researchers towards the use of non-edible oils as economic resources for biodiesel production. Non-edible oils are suitable for biodiesel production due to several reasons such as their inappropriate property to human nutritional systems [14–15]. Transesterification reaction is employed either in the absence or in the presence of catalysts. In non-catalyzed transesterification reaction, the reaction proceeds very slow with low reaction yield [16]. Generally, transesterification reaction ⁎ Corresponding author. E-mail address: [email protected] (N.A. Negm).

http://dx.doi.org/10.1016/j.molliq.2017.03.043 0167-7322/© 2017 Elsevier B.V. All rights reserved.

of oil into biodiesel is catalyzed by either homogeneous or heterogeneous catalysts [17–19]. Homogeneous catalysts including: sodium hydroxide, potassium hydroxide, sodium methoxide and potassium methoxide are the most usable catalysts in biodiesel production [20]. Through these catalysts, sodium and potassium methoxide are the most active with high biodiesel conversion percent of 95–98% in a relatively fast reaction [21–22]. In spite of the advantages of the homogeneous catalysts, some limitations limit their use in the transesterification process such as undesirable saponification products, alkali contaminations and their corrosive risk, and lack of catalysts reuses. In order to overcome these disadvantages, heterogeneous catalysts including solid catalysts or enzymes are used to catalyze the transesterification reactions of oils [23]. Heterogeneous catalysts are preferable than homogeneous catalysts in several advantages such as easy recovery of catalysts, reusability, easy and simple purification of the produced biodiesels and glycerol [24], neutralization of products is not required [25], and low water and energy consumption during the reaction. Several heterogeneous catalysts were developed to catalyze the transesterification reaction of oils including: calcined sodium silicate [26], alkaline earth metal oxides [27], Mg–Al hydrotalcite catalysts [28], 4-sulfophenyl activated carbon [29], Sodium titanate nanotubes doped with potassium [30], and Mg-Zn mixed oxides [31]. In this study, a novel heterogeneous catalyst of sulphonated phenyl silane montmorillonite was prepared by chemical modification of

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N.A. Negm et al. / Journal of Molecular Liquids 234 (2017) 157–163

montmorillonite clay and chemically characterized. The prepared catalyst was used to catalyze transesterification reactions of castor oil and jatropha oil. The transesterification reaction conditions were optimized using the prepared catalyst and the obtained biodiesel properties were studied using physical measurements and engine test performance. 2. Methods 2.1. Materials Castor oil and jatropha oil used in the study were obtained from the local market and were used after centrifugation to separate the solid contaminants and water. The properties and fatty acid profiles of the two oils were listed in Table 1.

6 h. After cooling to room temperature, the precipitate was filtered off, washed by excess dichloromethane, and dried under vacuum at 50 °C for 2 h to obtain phenyl silicate montmorillonite (Si-MMT-ph) [32]. 2.2.3. Preparation of sulfonated phenyl silicate montmorillonite (Si-MMTPh-SO3H) Si-MMT-Ph catalyst (6 g) was dispersed in 1,2-dichloroethane (100 mL) as a solvent and chlorosulfonic acid (3 g) was added in 250 mL round flask at 0 °C and vigorously stirred for 12 h at 50 °C. Then, the reaction medium was concentrated by evaporating the solvent using rotatory evaporator. The obtained precipitate was filtered off, washed several times by 1,2-dichloroethane and dried in vacuum oven at 50 °C to obtain sulfonated phenyl silicate montmorillonite (SiMMT-Ph-SO3H) [33].

2.2. Preparation of catalyst (sulphonated phenyl silane montmorillonite, SiMMT-ph-SO3H)

2.3. Catalyst characterization

Sulphonated phenyl silane montmorillonite catalyst (Si-MMT-PhSO3H) was prepared throughout three reaction steps. The first preparation of silicate montmorillonite (Si-MMT), the second is preparation phenyl functionalized silicate montmorillonite (Si-MMT-ph) and the third is preparation of sulfonated phenyl silicate montmorillonite (SiMMT-Ph-SO3H). Montmorillonite clay is characterized by its low price raw materials and has activity in several reactions. Furthermore, its preparation steps are very easy to perform without much expensive chemicals. Modification of the chemical structure of montmorillonite by increasing its acidic active sites increased its activity considerably. The nature of the acidic groups introduced in its framework increased its stability and consequently its reusability in the chemical reactions.

BET surface areas, pore volume and pore size distribution were measured by N2 adsorption/desorption at liquid N2 temperature (77.3°K) using an Autosorb-1 Quantachrome AS1Win, (Quantachrome, USA) instrument. Powder X-ray diffraction (XRD) patterns of the catalyst were recorded on Philips Powder Diffract meter with Cu Kα radiation operated at 40 KV and 40 mA with a scanning rate of 2° in 2θ/min in a scan range of 2θ = 4–80°. FT-IR spectra of the catalyst was obtained using ATI Mattson model Genesis Series (USA) infrared spectrophotometer using KBr technique. High resolution transmission electron microscope (HRTEM) images were obtained for ultrasonically suspended and deposited catalyst on a carbon film supported on a copper grid by using a Jeol 2010-300 W1 system operating at 130 kV.

2.2.1. Preparation of silicate montmorillonite (Si-MMT) Acidic MMT (5 g) was swelled in 250 mL distilled water for 2 h and 13.5 g of dodecyl amine dissolved in 2-propanol (200 mL) were charged in 500 mL round flask under mechanical stirring for 2 h. Tetraethyl orthosilicate (TEOS) (50 mL) was then added to the reaction matrix and aged for 4 h at room temperature until a white precipitate was obtained. The product was filtered, washed by acidified distilled water, dried in oven at 75 °C and finally air calcined at 600 °C for 5 h to obtain silicate montmorillonite (Si-MMT). 2.2.2. Preparation of phenyl functionalized silicate montmorillonite (SiMMT-ph) Si-MMT-ph was prepared by post grafting reaction using trimethoxy phenyl silane. Si-MMT (5 g) was dispersed in n-hexane (100 mL) for 30 min in 500 mL round flask and then trimethoxy phenyl silane (2.5 g) was added to reaction medium under stirring and reflux for Table 1 Fatty acid profile of the used castor oil and jatropha oil. Fatty acid

Castor oil Composition (wt%)

Jatropha oil

Palmitic acid (16:0) Palmitoleic acid (16:1) Stearic acid (18:0) Oleic acid (18:1) Linoleic acid (18:2) Linolenic acid (18:3) Arachidic acid (20:0) Ricinoleic acid (18:1, OH) Acid value, (mg KOH/g) Viscosity at 40 °C, (mm2/s) Density, (kg/m3) at 15 °C Cloud point, (°C) Pour point, (°C) Oxidation stability, (h) Iodine value, gI2/100 g oil Sulfur content

1.00 – – 3.00 5.00 1.00 – 89.00 3.0 43.0 0.959 8 3 5.5 80.5 0

15.20 0.70 6.80 44.60 32.20 – 0.20 – 3.80 37.0 0.910 8 3 2.56 104.46 0

2.4. One step transesterification reaction of oils using Si-MMT-Ph-SO3H catalyst Transesterification reaction of castor oil and jatropha oil were carried out in a round bottom flask (250 mL). Generally, the transesterification reaction was preceded by mixing the methanol, oil and catalyst. The mixture was heated under stirring condition for the desired reaction time. At the end of the reaction, excess methanol was removed under reduced pressure and the reaction mixture was allowed to cool to room temperature, centrifuged to separate the different phases. After centrifugation, three layers were separated: the upper layer is the obtained biodiesel; the middle layer contains the produced glycerol, and the lower layer contains the catalyst and traces of glycerol [34]. The procedures of optimizing the transesterification reaction parameters of castor oil and jatropha oil using the prepared Si-MMT-Ph-SO3H catalyst were performed considering the following points: catalyst was dispersed in methanol under stirring; oil was added to the reaction medium under continuous stirring; oil to methanol ratio was varied from 1:3 to 1:12 by weight; catalyst % was varied from 1% to 8% by weight; the reaction was performed in the time range of 1–5 h; the reaction temperature was varied within the range of 40–120 °C. The obtained biodiesels from the two oils was separated and quantified for the percentage of triglyceride, diglyceride, monoglyceride and the ester content by silica gel column chromatography using GC-7890A equipped with DB-23 column, 60 mm × 0.25 mm, i.d. of 0.25 μm. 2.5. Oils and FAMEs specifications The castor oil and jatropha oil were characterized in terms of refractive index, saponification and iodine values, acid value and water content. The transesterified products were characterized in terms of kinematic viscosity, iodine value, density, cetane number, pour point, cloud point, ash content, carbon residue, flash point, and fire point according to ASTM specifications [35–43].


159

2.6. Engine test A four stroke single cylinder direct injection diesel engine was used to perform the engine tests for the obtained biodiesels and diesel-biodiesel blends using of capacity 624 cm3. The test was performed at speed engine of 1500 rpm with different loads at 6.37, 12.74, 19.11, 22.3 and 25.48 N, fuel volume 50 cm3 for petroleum diesel and three petroleum diesel-biodiesel blends of 10% biodiesel (B10), 20% biodiesel (B20) and 40% biodiesel (B40). Time of fuel consumption (s) and the brake power (kW) were recorded for the different blends. The break specific fuel consumption, BSFC (gm/kWh) and the break thermal efficiency, BTE (%) were calculated as follows: BSFC = (Rate of fuel consumption / Brake power); BTE = (Brake Power × 360,000) / (Rate of fuel consumption × Calorific value), where: fuel consumption rate in gm/h, brake power in kW, and Calorific value in kJ/g [44]. 3. Results and discussion 3.1. Catalyst characterization The prepared sulfonated phenyl silicate montmorillonite (Si-MMTPh-SO3H) catalyst was characterized by BET surface area, XRD, HRTEM, and FTIR techniques. BET surface area isotherms and values of Si-MMT-Ph-SO3H catalyst and the catalyst intermediates (MMT, Si-MMT) are listed in Table 2. The isotherm of the raw MMT sample is of type IV according to IUPAC classification, [45]; exhibiting H3 hysteresis loops Fig. 1. This type indicates the presence of aggregates of plate-like particles giving rise to slide-shaped pores [46]. The isotherms display hysteresis loops extending down to P/P0 ≈ 0.2 ≈ 0.4 for all samples. The values of specific surface area calculated using the linear form of the BET-equation in BET in the conventional P/P0 range: 0.05–0.3 [47] and the pore volume and average pore radius are given in (Table 1). Si-MMT shows the highest value of BET and VP, meanwhile the smallest average pore radius. The higher adsorption of P/P0 for Si-MMT is attributed to the large number of narrow pores. BET value is significantly decreased upon modification in Si-MMT-Ph-SO3H than Si-MMT while the total pore volume showed a very slight decrease, consequently the average pore radius showed a remarkable decrease. These variations can be explained as the addition of phenyl sulfonic acid (Ph-SO3H) blocking the narrow pores which decreases the surface area [48]. XRD pattern of the MMT, Si-MMT and Si-MMT-Ph-SO3H are showed in Fig. 2. The XRD pattern of MMT matrix exhibited diffraction peaks at 2θ = 8.82°, 19.93°, 36.50°, and 61.89° as reported [49]. IR peaks proved the presence of cristobalite, quartz and feldspar contaminants [50]. Inspecting the XRD spectra of MMT, Si-MMT and Si-MMT-Ph-SO3H showed a shifting of (001) peak at 2θ = 8.82° towards lower 2θ value is due to the intercalation of trimethoxy phenyl silane groups in MMT interlayer. HR-TEM images of MMT, Si-MMT and Si-MMT-Ph-SO3H are shown in Fig. 3. The structure of MMT is composed of stacking layers in agreement to the typical layered materials. A wormhole pore and sponge-like network porous structure were demonstrated for both Si-MMT and SiMMT-Ph-SO3H. Moreover, no destruction or pore blocking is observed after sulfonation of grafted phenyl silane moieties on Si-MMT.FT-IR spectra of MMT, Si-MMT, and Si-MMT-Ph-SO3H are shown in Fig. 4. In case of MMT, the absorption band in the rang of 3100–3500 cm−1 and

Fig. 1. Nitrogen adsorption isotherms and pore size distribution of MMT, Si-MMT and SiMMT-Ph-SO3H.

centered at 3450 cm−1 assigned to the stretching vibrations of Al-OH and water molecules; the absorption band at 794 cm− 1 referred to stretching vibration of AlIV tetrahedral [51]. The band at 1094 cm−1 is due to the assymmetric Si\\O stretching vibration, and a band at 1630 cm−1 for MMT, Si-MMT and Si-MMT-Ph-SO3H referred to H\\O\\H bending vibration of sorbed water molecules on the montmorillonite surface [52]. Comparing the absorption bands arround 1630 cm−1 for MMT, Si-MMT and Si-MMT-Ph-SO3H comprises an increase in its intensity, which can be attributed to the increase in hydrophilicity of MMT due to its conversion into Si-MMT and Si-MMT-PhSO3H, respectively. Also, the absorption band located in 3400– 3600 cm−1 range is remarkabley enhanced in case of Si-MMT as a result of increasing the amount of adsorbed water molecules at the surface (SiMMT has the highest surface area). The absorption bands intensities at 970 cm−1 and 566 cm− 1 were enhanced in case of Si-MMT and SiMMT-Ph-SO3H than MMT indicating indicating the presence of more OH and SiO groups in the silica frame structure between the layers of MMT. The Si-MMT-Ph-SO3H showed broad band at 3100 cm−1 correspond to stretching vibration of C_C of aromatic rings, the bands at 880 and 860 cm−1 indicating the presence of phenyl ring. The bands

Table 2 Surface properties of various samples prepared. Sample

Surface area, (m2 g−1)

Pore radius, (Å)

Pore volume, (cm3 g−1)

MMT Si-MMT MMT-Ph-SO3H

220 795 260

15.54 12.07 11.15

0.342 0.96 0.29

Fig. 2. XRD powder patterns of MMT, Si-MMT and Si-MMT-Ph-SO3H.

160


Fig. 3. HRTEM of MMT, Si-MMT and Si-MMT-Ph-SO3H samples.

at 1179 and 1020 cm−1 corresponded to SO3 stretching and O_S_O stretching in SO3H, respectively, indicate the subistitution of SO3H group on the phenyl rings [53].

results are in good agreement with the published data reported on the use of heterogeneous catalysts in transesterification reactions of castor oil and jatropha oil [56,57].

3.2. Transesterification of oils with methanol

3.2.2. Effect of oil to methanol ratio The transesterification reactions of castor oil and jatropha oil were performed at oil to methanol ratio of 1:3, 1:6, 1:9, and 1:12 using the prepared Si-MMT-Ph-SO3H catalyst (5% by weight relative to oil). The obtained conversion % of the different oils to the corresponding FAMEs was listed in Table 4. It is clear from Table 4 that 1:3 molar ratio of oil to methanol gave the lowest conversion of oil into FAMEs at 25% and 47.8% for castor oil and jatropha oil, respectively, using Si-MMT-Ph-SO3H catalysts. It is also clear that the gradual increase of oil to methanol ratio increases the conversion of both oils into their corresponding FAMEs. The maximum conversions of castor oil and jatropha oil were 89.8% and 98.0% at 1:12 and 1:6 molar ratio of oil/methanol, respectively, using Si-MMT-Ph-SO3H catalyst. Increasing the oil/methanol molar ratio more than 1:12 (in case of castor oil) and 1:6 (in case of jatropha oil) has no considerable influence on their conversion ratio. The obtained results are in line with the reported results [58–60].

The prepared Si-MMT-Ph-SO3H catalyst was used as a heterogeneous catalyst in the transesterification reaction of castor oil and jatropha oil. The transesterification reaction parameters were optimized to obtain the maximum yields of fatty acid methyl esters of both oils including: catalyst concentration, oil to methanol ratio, reaction time and temperature. 3.2.1. Effect of catalyst concentration The effect of Si-MMT-Ph-SO3H catalyst concentration on the transesterification reaction of castor oil and jatropha oil is varied by increasing the catalyst wt% from 1% to 7%, relative to the oil weight (Table 3). Table 3 represents that the gradual increase of the catalyst concentration in the transesterification reactions of castor oil and jatropha oil is gradually increased their conversion percents to the corresponding FAMEs (biodiesel); while increasing the catalyst concentration than 5% has no considerable effect on the conversion percent. The maximum conversion obtained was 89.8% and 98.5% using 5% of SiMMT-Ph-SO3H for castor oil and jatropha oil, respectively. The gradual increase of conversion (%) of oil to biodiesel by increasing the catalyst concentration can be attributed to the increase of catalytic active sites of the catalyst participated in the reaction [54]. Further increase in catalyst concentration over 5% decreases the obtained biodiesel. This can by refer to the increase in the viscosity of the reaction medium which decreases the interaction between the catalyst and reaction component and consequently, a part of the catalyst remains unused [55]. These

3.2.3. Effect of reaction time The conversion percents of castor oil and jatropha oil into the corresponding FAMEs using Si-MMT-Ph-SO3H catalyst were followed over a reaction time interval of 60, 120, 150, 180, 240, 300 and 360 min, Table 5. It is clear from Table 5 that the conversion of the oils into the corresponding FAMEs is increased by increasing the reaction time to reach to the maximum conversion values of 90.3% for castor oil after 300 min, and 98% for jatropha oil after 180 min. Further increase in the reaction time slightly decreases the obtained amount of FAMEs obtained. That can be attributed to the reversible nature of the transesterification reaction, which starts to reverse the forward reaction (FAMEs formation) towards the backward reaction (hydrolysis of FAMEs) [61,62]. It is reported [44] that the maximum reaction time of transesterification reaction is 90 min using the homogeneous catalyst while in case of heterogeneous catalysts; the reaction takes longer time to obtain the same conversion %. This can be ascribed to the

Table 3 Effect of catalyst concentration on the transesterification reaction of castor oil and jatropha oil. Catalyst wt%

Fig. 4. FTIR spectra of MMT, Si-MMT and Si-MMT-Ph-SO3H.

1 2 3 5 7

Oil conversion % to FAMEs Castor oil

Jatropha oil

47 84.5 89.4 89.8 88.7

60.2 95.5 97.1 98 96

N.A. Negm et al. / Journal of Molecular Liquids 234 (2017) 157–163 Table 4 Effect of oil to methanol ratio on the transesterification reaction of castor oil and jatropha oil. Oil to methanol ratio

Table 6 Effect of temperature on transesterification reaction of castor oil and jatropha oil. Temperature, °C

Oil conversion % to FAMEs

1:3 1:6 1:9 1:12

Castor oil

Jatropha oil

25.0 46.0 79.0 89.8

47.8 98.0 97.7 96.0

161

40 50 60 70


Jatropha oil

65 87.5 89.8 86.4

90 100 110 120

76.5 93.5 98 93.5

3.3. Catalyst reusability reaction mechanism which proceeds via three phase system, oil-methanol-catalyst [63], while homogeneous catalyzed through two steps reaction, the glycerol separation and methanolysis of separated fatty acids [64,65].

3.2.4. Effect of temperature The reaction temperature has a considerable effect on the transesterification reaction of vegetable oils. Generally, increasing the reaction temperature lead to increases the reaction rate and the reaction conversion. In case of homogeneous catalysts, the conversion of oils into FAMEs is gradually increased by increasing the temperature up to 60 °C, while further increase in temperature decreases it due to the saponification reaction [44,66]. Heterogeneous catalyzed transesterification reaction of vegetable oils has similar behavior of homogeneous catalyzed reaction. The transesterification reactions of castor oil and jatropha oil were performed using Si-MMT-Ph-SO3H catalyst at temperature of 40–70 °C in case of jatropha oil, and at 90–120 °C in case of castor oil, Table 6. In case of Castor oil, the maximum conversion % was 89.8% SiMMT-Ph-SO3H at 60 °C, whereas, increasing the reaction temperature to approximate 70 °C leads to a decrease in the biodiesel conversion % to 86.4%. In case of jatropha oil, the obtained conversion % was very low at the initial reaction temperature of 40–70 °C. The conversion % was started to increase to 76.5% at 90 °C. Increasing the temperature above 90 °C gradually increases the oil conversion % to reach the maximum of 98% at 110 °C, whereas the conversion % of oil to biodiesel starts to considerably decrease by increasing the temperature above 110 °C. The obtained results are in accordance with the reported data [63,67– 68]. Also, the published data reported that jatropha oil undergoes transesterification reaction at high temperature than Castor oil does [69,70].

3.2.5. Optimized conditions of transesterification reaction From the previous optimization study of transesterification reaction of castor oil and jatropha oil using the prepared Si-MMT-Ph-SO3H, the optimum conditions can be extracted as fallow: in case of Castor oil: (1:12) oil to methanol molar ratio and 5 wt% catalyst at 60 °C for 300 min at 800 rpm, to obtain conversion % of oil to FAMEs of 89.8%. In case of jatropha oil: (1:6) oil to methanol molar ratio and 5 wt% catalyst at 110 °C for 150 min at 800 rpm, to obtain conversion % of oil to FAMEs of 98%.

During the transesterification reaction, the products of the reaction includes: glycerol, biodiesel and excess methanol. The catalyst of the reaction is contaminated by the reaction product (mainly glycerol). The purification of the catalyst is performed by washing with distilled water, dried and calcined at 450 °C for reactivation. The reusability of the catalyst is an important characteristic parameter in using heterogeneous catalysts. This is due to the economic impact of the used catalyst in decreasing the whole cost of the operation. Regeneration of the catalyst provides low cost and consequently decreases the overall price of the final product. In order to determine the reusability of the prepared catalyst, nine rounds reaction were performed including the first trial. The result of each experiment, expressed in term of conversion %, is profiled in Fig. 5. It is clear from comparing the obtained results in Fig. 5 that Si-MMT-Ph-SO3H catalyst has good reusability during the transesterification reactions of castor oil and jatropha oil. The first trial gave 89.8% and 98% conversion for castor oil and jatropha oil into FAMEs, respectively. Repeating the reaction using the same used catalyst after activation for two times gave identical products % in case of jatropha oil and nearly products % in case of castor oil. Further using of the catalyst after activation is gradually decreasing the conversion % of the biodiesel to reach conversion ratios of 85% and 92% for castor oil and jatropha oil, respectively at the seventh round. Higher rounds show a significant depression in the conversion % of oil to biodiesel.

3.4. Leaching of catalyst Leaching property represents the ability of catalyst to dissolve in the alcohol used in the transesterification reaction. The leaching of catalyst is considered a serious disadvantage in the heterogeneous catalyst property. Leaching leads to contamination of the final products (biodiesel and glycerol) by undesirable compounds. This requires more purification steps and consequently higher costs. Leaching experiments of SiMMT-Ph-SO3H catalyst include dispersing the catalysts in methanol for 2 h, then the methanol is filtrated, and oil is added to the methanol and reflux for 1 h. The reaction showed no change in the properties of the used oils, which indicates the stability of the active sites of Si-MMT-

Table 5 Effect of reaction time on the conversion of castor oil and jatropha oil to FAMEs. Time, min


Jatropha oil

60 120 150 180 240 300 360

58.3 67.1 72.6 76.8 85.6 89.8 89.4

60 97.4 98 97.3 92.3 91.7 91.1

Fig. 5. Reusability of Si-MMT-Ph-SO3H catalyst in transesterification reaction of castor oil and jatropha oil.

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3.6. Engine performance of castor oil biodiesel

Table 7 Properties of biodiesel obtained from castor oil and jatropha oil. Property

Unit

Test limits

Castor oil biodiesel

Jatropha oil biodiesel

Density Kinematic viscosity at 40 °C Flash point Cloud point Pour point Boiling point Cetane number Sulfur content

gm/cm3 cSt. °C °C °C °C – wt%

0.860–0.900 4.0 to 6.0 100–170 −3 to 15 −5 to 10 315–350 48–65 0.0–0.0024

0.9183 6.89 176 −6 −18 356 54 0.001

0.8912 4.4 168 −6 −15 320 58 NIL

Engine test represents the behavior and characteristics of the prepared biodiesels and their blends by petroleum diesel in the diesel engines. Engine test parameters of the petroleum diesel and three blends by the obtained biodiesels (B10, B20, and B40) from transesterification of castor oil and jatropha oil using Si-MMT-Ph-SO3H catalyst are listed in Table 8. It is clear from the data obtained that the efficiency of the diesel engine was improved at full loading in case of the B10; thereby the brake specific fuel consumption is decreased in case of castor and jatropha oil biodiesels blends of B10 and B20 compared to 312.37 g/kWh for petroleum diesel. The calculated brake thermal efficiencies were increased for the biodiesels blends of B10 compared to that of petroleum diesel. The thermal efficiency decreased in case of B10 blends compared to 25% of petroleum diesel. Results in Table 8 showed the enhancement of the fuel properties of the obtained biodiesels blends compared to the petroleum biodiesel, and the best blending ratio is 10% of biodiesel to 90% petroleum diesel.

Ph-SO3H catalyst and the purity of obtained biodiesel and glycerol [64,71]. The leaching test of Si-MMT-Ph-SO3H catalyst in the reaction medium showed its high stability during the transesterification reaction.

4. Conclusions 3.5. Properties of biodiesel The study of biodiesel production from castor oil and jatropha oil using novel transesterification catalyst was carried out. The results show the prepared catalyst and castor oil and jatropha oils can be considered as valuable resources to obtain biodiesel in one step process. The key conclusions obtained from the study are: 1. Sulphonated phenyl silane montmorillonite catalyst can be prepared throughout simple reaction steps with low price chemicals. 2. Sulphonated phenyl silane montmorillonite catalyst can be used as an efficient transesterification catalyst in production of biodiesel from castor oil and jatropha oil.

The physical properties of the obtained biodiesels from the transesterification reactions of castor oil and jatropha oil using SiMMT-Ph-SO3H catalyst under the optimized conditions were determined. The properties were compared to ASTM standard values. The measured properties were: specific gravity; kinematic viscosity at 40 °C; flash point, cloud point, pour point, boiling point, cetane number and sulfur content, Table 7. It is clear from the data listed in Table 7 that the physical properties of the obtained biodiesels are located within the standard specifications. Table 8 Engine test results for petroleum diesel and biodiesels blends. Fuel

Load, N

Brake power, kW

Fuel volume (mL)

Time of fuel consumption, (s)

Fuel consumption, g/h

BSFC, gm/kWh

Brake thermal efficiency, %

Petroleum diesel

6.37 12.74 19.11 22.3 25.48 6.37 12.74 19.11 22.3 25.48 6.37 12.74 19.11 22.3 25.48 6.37 12.74 19.11 22.3 25.48 6.37 12.74 19.11 22.3 25.48 6.37 12.74 19.11 22.3 25.48 6.37 12.74 19.11 22.3 25.48

1 2 3 3.5 4 1 2 3 3.5 4 1 2 3 3.5 4 1 2 3 3.5 4 1 2 3 3.5 4 1 2 3 3.5 4 1 2 3 3.5 4

50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50

232.3 208 177.8 155.9 121 250.2 191.1 150.9 129.5 120.3 247.54 172.05 151.74 133.05 112.68 169.81 152.87 137.96 110.30 96.43 245.0 187.1 147.8 126.8 118.6 242.3 168.4 148.5 130.2 110.3 166.2 149.7 135.1 108.0 94.4

651 727 850.4 964.7 1249.5 545.2 714.6 903.9 1053.8 1126.6 551.25 793.11 899.27 1025.62 1211.02 803.70 893.00 988.57 1237.19 1415.50 533.7 699.1 884.8 1031.6 1102.9 539.6 776.4 880.3 1004.0 1185.5 786.8 874.2 967.8 1211.1 1385.7

651 363.5 283.4 275.6 312.3 545.2 357.1 301.3 300.2 281.5 551.25 396.53 269.80 292.87 302.76 803.70 446.50 329.65 359.10 353.88 533.7 349.5 294.9 293.9 275.7 539.6 388.2 264.1 286.7 296.4 786.8 437.1 322.7 351.5 346.4

15 24.2 28.3 29 25 13.40 20.43 24.23 24.35 25.99 13.41 18.66 27.36 25.27 24.42 9.22 16.57 24.88 20.62 20.90 13.1 20.0 23.7 23.8 25.4 13.1 18.3 26.8 24.7 23.9 9.0 16.2 24.4 20.2 20.5

Castor oil biodiesel/petroleum diesel blends

B10

B20

B40

Jatropha oil biodiesel/petroleum diesel blends

B10

B20

B40


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