Biodiesel production from waste fish oil with high free fatty acid content from Moroccan fish-processing industries

Egyptian Journal of Petroleum xxx (2017) xxx–xxx

Contents lists available at ScienceDirect

Egyptian Journal of Petroleum journal homepage: www.sciencedirect.com

Full Length Article

Biodiesel production from waste fish oil with high free fatty acid content from Moroccan fish-processing industries K. Kara a, F. Ouanji b,⇑, El M. Lotfi a, M. El Mahi a, M. Kacimi b, M. Ziyad b,c a

Laboratory of Mechanics and Industrial Processes, Chemical Sciences Research Team, Mohammed V University in Rabat, Morocco Laboratory of Physical Chemistry of Materials and Catalysis, Department of Chemistry, Faculty of Sciences, Mohammed V University in Rabat, Morocco c Hassan II Academy of Science and Technology, Rabat, Morocco b

a r t i c l e

i n f o

Article history: Received 1 March 2017 Revised 6 July 2017 Accepted 27 July 2017 Available online xxxx Keywords: Fish oil Purification Biodiesel Alternative fuel Esterification Transesterification

a b s t r a c t Moroccan waste fish oil was used as raw material to produce the biodiesel in this study. The biodiesel sample is achieved by a dual step esterification-transesterification acid-base to reduce the higher FFAs content of fish oil after a rapid method of purification. It is characterized by techniques such as Fourier Transform Infrared spectroscopy (FTIR), Nuclear Magnetic Resonance (NMR) spectroscopy, and the Gas Chromatography–Mass Spectrometry (GC/MS). The experimental results showed that biodiesel produced from waste fish oil contained a significantly greater amount of methyl ester group in the biodiesel sample. The GC/MS results showed the presence of a good quantity of palmitic acid, oleic acid and linolenic acid which are essential biodiesel components. The biodiesel did not contain any trace of glycerol and it did meet international standards. Ó 2017 Egyptian Petroleum Research Institute. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

1. Introduction Nowadays, fishing is one of our most important industries which always try hard to increase the production of fisheries. Morocco is located in northwest Africa. It is bordered on the north by the Mediterranean Sea, on the south by Mauritania, on the east by Algeria and on the west by the Atlantic Ocean. Morocco is the first world producer of sardines called ‘‘Sardina pilchardus” and is also the second largest supplier of fish in Africa after Nigeria [1]. This wealth has led to an increased development of production, transformation and preservation of fish industries which generate large amounts of waste, A percentage of the total catch of fish is isolated as processing leftovers such as heads, fins, skin, frames, trimmings and viscera. More complete utilization is achieved by conversion of leftovers into fishmeal and fish oils. Indeed, the quantities of fish waste are estimated at several hundred thousand tons of waste per year [2], while experiments showed that fish oil recovered from fishmeal residue varies considerably between a mass fraction of 1.4% and 40.1% depending on the species, tissue and season [3]. Therefore, it would be useful to insist on the impor-

Peer review under responsibility of Egyptian Petroleum Research Institute. ⇑ Corresponding author. E-mail address: [email protected] (F. Ouanji).

tance of treatment and recovery of fish waste to avoid any effect on the environment in general and on human health in particular. In fact, many recent studies have been interested in the valorization of fish-waste. The one that has received the greatest attention is the synthesis of a biofuel that meets the security of supply criteria: response to local development needs ensuring the reduction of the production of CO2, the main greenhouse gas emissions. Biofuel is an alternative fuel for diesel engines. It can be used in pure form (B100) or may be blended with petroleum diesel at any concentration in most injection pump diesel engines [4–8].The biodiesel yield ranges between 80 and 95 wt% depending on the quality and the purity of the oil [9]. Research in this field is managed in order to improve the process of converting vegetable oil or animal fat into biodiesel. That is usually produced by different processes. Transesterification reaction is the most common method in the production of biodiesel. Some researchers indicated that the physical properties of biodiesel from fish waste oils, including viscosity and acidity, are much higher than regular diesel [9] which causes problems in performance and NOx in the combustion of diesel engines [6,10]. It was noted that the acid value marked variation between different batches of fish (viscera, skin and muscle), and different type of fish [3]. Furthermore, it was found that due to the high acid value of salmon oil, alkaline-catalyzed transesterification was not an effective method for producing biodiesel from salmon oil [11],

http://dx.doi.org/10.1016/j.ejpe.2017.07.010 1110-0621/Ó 2017 Egyptian Petroleum Research Institute. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Please cite this article in press as: K. Kara et al., Biodiesel production from waste fish oil with high free fatty acid content from Moroccan fish-processing industries, Egypt. J. Petrol. (2017), http://dx.doi.org/10.1016/j.ejpe.2017.07.010

2

K. Kara et al. / Egyptian Journal of Petroleum xxx (2017) xxx–xxx

which indicates that the adopted process requires adjustment [8]. Moreover, other researchers showed that animal fat as well as vegetable oil have a higher heating value similar to that of the ordinary diesel, but the problem is their acidity which is superior to those of diesel [12]. The biodiesel produced from fish oil had a higher heating value compared to those of animal fat or vegetable oil [13]. It is also noted that the oil or fat used in the transesterification by basic catalysis should contain less than 0.5% free fatty acid (FFA) [14]. It has been known that, when the FFA level exceeds 0.5%, the soap formation occurs and inhibits the separation between the biodiesel and glycerol, and decreases the yield of the final product. Consequently, the direct transesterification by basic catalysis of this oil is not applicable. The pretreatment of this oil to remove the FFA and the water is usually required. In this paper, acid catalyzed esterification and base catalyzed transesterification were used, respectively, to reduce the higher FFA content of waste fish oil and to produce biodiesel respectively. Initially, the esterification reaction was performed to investigate the effect of various reaction parameters on the reduction of free fatty acid content in waste fish oil. Methanol/oil ratio, catalyst amount, reaction temperature and time were optimized to determine the optimum conditions in the pretreatment step which gave the lowest acid value. Then, the second step, base catalyzed transesterification in which oil reacts with methanol in the presence of an alkaline catalyst (KOH) to form ester and glycerol, is performed. 2. Materials and methods 2.1. Materials The feedstocks, Waste Fish Oil (WFO) sample, used in this study was supplied by Kilimanjaro Environment Company (Casablanca, Morocco) which is specialized in the collection of used vegetable and animal oils. It is recovered as waste from fish meal and oil plant operations. The chemicals were used without any prior purification: Sodium hydroxide (
97%), potassium hydroxide (85–100%), diethyl ether (
99.5%) and methyl heptadecanoate (
99%) were purchased from Sigma-Aldrich, while methanol (
99.9%), ethanol (
99.9%) were supplied by Fluka, Hexane (95%), and cyclohexane (99.9%), and sulfuric acid (96%) were purchased from Panreac.

Spectroscopy can be used for the determination of the conversion of transesterification reaction in progress. The conversion is illustrated by the following equation as previously described [7,16].

C ¼ 100x

2AMe 3ACH2

ð1Þ

where: C = conversion of triacylglycerol feedstock to the corresponding methyl ester. AMe = integration value of the protons of the methyl esters (the strong singlet peak). ACH2 = integration value of the methylene protons. The factors 2 and 3 derive from the fact that the methylene carbon possesses two protons and the alcohol (methanol-derived) carbon has three attached protons. 2.3. Biodiesel production 2.3.1. Pretreatment of the waste fish oil First, the oil was filtered under vacuum to remove any solid impurities and a portion of water. Then, it was degummed with phosphoric acid and water to remove polar component such as phospholipids, lecithins, pigments and some contaminant such as heavy metals. The neutralization was realized by the addition of potassium hydroxide to remove free fatty acids as soap. Silica gel column chromatography was then applied to remove remaining impurities and colorant using (90% cyclohexane and 10% Ethyl Acetate) as solvent. It was also dried simply by heating at 105 °C in 15 min. This time was determined by monitoring the weight loss upon heating. Finally, the deodorization was carried out by heating under vacuum. The intensity of the scent is followed by a simple flair, and it was weighed into a Pyrex tube then subjected to vacuum heating at 90 °C. Fig. 1 illustrates fish oil before and after purification. 2.3.2. Esterification-Transesterification process Biodiesel production from WFO was performed by Esterifica tion-transesterification occurred out in two steps. First, the esterification reaction was performed in a three-neck round bottom flask (Ace Glass Inc.) equipped with a thermometer to measure the temperature, a water cooled condenser was connected to another neck

2.2. Methods The physical and chemical properties such as viscosity, density, acid value of the reactants and the produced biodiesel were determined according to the ASTM standards. The obtained values were compared with the European standards of biodiesel [15]. To determine the fatty acid profile of waste fish oil and FAME produced in this work, a 2000 TR thermo gas chromatograph was used with a flame ionization detector (FID) and a capillary column DB-WAX (30 m  0.32 mm, 0.23 mm film thickness). Helium was used as carrier gas. The temperature program started at 60 °C (for two min) and continued with a ramp of 6 °C/min to 150 °C (for 10 min), and then with a ramp of 10 °C/min to 250 °C (for 2 min). Infrared spectral data were collected by using a VERTEX 70 spectrometer equipped with ATR MIRACLE DIAMANT technique. The device had a spectral range of 4000–650 cm1.and spectral data were collected by co-adding 16 scans at a resolution of 4 cm1. The 1H-NMR spectra were recorded at 298 K with a BRUKER AVANCE 300 MHz spectrometer. Deuterated chloroform (CDCl3) was used as solvent. 1H-NMR spectra were recorded with pulse duration of 30°, a recycle delay of 1.0 s and 8 scans. The 13C NMR (75 MHz) spectra were recorded with pulse duration of 30°, a recycle delay of 1.89 s and 160 scans. Nuclear Magnetic Resonance

Fig. 1. Waste fish oil before and after purification.

Please cite this article in press as: K. Kara et al., Biodiesel production from waste fish oil with high free fatty acid content from Moroccan fish-processing industries, Egypt. J. Petrol. (2017), http://dx.doi.org/10.1016/j.ejpe.2017.07.010

K. Kara et al. / Egyptian Journal of Petroleum xxx (2017) xxx–xxx

on top of the reactor to reduce evaporative loss of methanol. The third neck is used for chemical addition and taking samples. The reactor was heated on a hotplate (Fisher Scientic, 11-100-100SH). For each esterification run, a volume of acidic waste vegetable oil was added into the reactor and heated to the desired temperature before addition of mixture of methanol and catalyst. Aliquot of samples was withdrawn from the flask for titration. The unreacted alcohol and water were removed by vacuum distillation using a BÜCHI Rotavap R-114 equipped with BÜCHI Water-bath B-48. The transesterification of esterified WFO was performed as follow: the oil, preheated at 60 °C was added with stirring to a solution of KOH in methanol, at different temperatures, times of reaction, methanol/oil ratio and catalyst amount. The resulting mixture was stored for 8 h in a separating funnel to isolate glycerol from biodiesel. The recovered methyl ester phase was purified using aqueous phosphoric acid solution (4% v/v) and water steam bubbling. The obtained liquid was dried at 80 °C and stored before analysis. The reactions as well as the washings were carried out in a systematic manner.

3

Fig. 2. 1H NMR spectrum of WFO.

3. Results and discussions 3.1. Characterization of waste fish oil (WFO) Chromatographic analysis allowed quantifying the oil content of fatty acids in the waste fish oil. The chemical composition and some characteristic of the WFO are listed in Table 1. It is observed that the used WFO had high acidity index (about 28% of free fatty acids), which suggests that the esterification process would be recommended for the production of biodiesel from this raw material. Regarding the physical parameters of the WFO, the lower viscosity value shows that fluidity of the fuel is improved compared to other raw materials, which might be an advantage to perform pretreatment reaction to reduce the FFA level [17]. On the other hand, it is important to note that waste fish oil composition depends on the oil history [18]. The WFO sample was also characterized by 1H-NMR spectroscopy (Fig. 2). The triplet appearing at 0.94 ppm presents the CH3 protons of linolenyl chain, while those appearing in the regions at 0.83–0.90 ppm stand for CH3 protons of saturated, oleyl, and linoleyl chains. The major spectral features of WFO (Fig. 3a) are CAH stretching vibration at 3010 cm1, three bands at 2960.5; 2929.4; 2851.7 cm1, assigned respectively to asymmetric stretching vibration CH2 group, asymmetric stretching CH3 group, and symmetric stretching CH2 group. Two distinct vibration bands are observed between 1700 and 1755 cm1. The ester carbonyl band C@O at 1735.5 cm1, and the band C@O between 1701 and 1721 cm1 assigned to FFA presents

Table 1 Physical properties and fatty acid methyl esters composition of waste fish oil. Parameters

Units

WFO

Viscosity (40 °C) Density (20 °C) Acid value

mm2/s g/cm3 mg KOH/g

4.3 0.942 56.1

Fatty acid type

Carbon chain

%

Myristic Palmitic Palmitoleic Stearic Oleic Lenoleic Linolenic Arachidic Behnic

C14: C16: C16: C18: C18: C18: C18: C20: C22:

1.19 10.19 14.79 21.76 24.93 11.58 9.31 1.38 0.98

0 0 1 0 1 2 3 0 0

Fig. 3. Infrared spectrum of WFO (a) PWFO (b) and EWFO (c).

in WFO that confirm the higher acidity value of WFO (28%). However, the presence of the acid was confirmed by the band CAO stretching vibration at 1164.7 cm1. The bands located at 1460 cm1, 1381 cm1, and 902 cm1 attributable respectively to deformation vibrations of CH2, CH3 groups, and OAH of carboxylic acid. The purification method reduces the acidity from 28 to 23% which is confirmed in FTIR spectrum by the band C@O at 1709.36 cm1 (Fig. 3b). 3.2. The two-step synthesis of biodiesel 3.2.1. First step: FFAs esterification with H2SO4 catalyst As mentioned before, the acid-catalyzed esterification has been applied to the purified fish oil as a pre-treatment method. It was carried out using H2SO4 as catalyst and methanol as reagent to reduce the acidity level of the waste fish oil. We tried to optimize the degree of esterification by choosing to vary the rate of catalyst, methanol to oil ratio and time. However, the temperature should not exceed the boiling point of methanol. The acid value was determined by titration technique. Eq. (2) was used to determine the acid value of WFO.

S¼

MKOH  V KOH  NKOH Þ moil

ð2Þ

Please cite this article in press as: K. Kara et al., Biodiesel production from waste fish oil with high free fatty acid content from Moroccan fish-processing industries, Egypt. J. Petrol. (2017), http://dx.doi.org/10.1016/j.ejpe.2017.07.010

K. Kara et al. / Egyptian Journal of Petroleum xxx (2017) xxx–xxx

FAAs conv ersion ¼

Si  St  100 Si

ð3Þ

3.2.2. Second step: transestrification The pretreated waste fish oil was preheated to a desired temperature in a reaction flask. The alkali-catalyzed transesterification was performed using KOH as catalyst and methanol as reagent in different conditions as shown in Table 2. The reaction was carried out in a 3 neck round bottom flask at 60 °C and with a constant stirring of 700 rpm. The heating and stirring processes were continued for different reaction times at atmospheric pressure. Catalyst amount of 1.5 wt% KOH and a molar ratio of 6:1 were enough to obtain biodiesel with high ester content by basictransesterification reaction. Yet, more amount than 0.5 wt% and 9:1 and 12:1 molar ratio appears to give the best results. A conversion of 99.1% was achieved with 9:1 methanol to oil molar ratio and 1 wt% of KOH which is in accordance with the conclusion of

FFAs conversion %

80

60

80

70

60

50 6

8

10

12

14

16

Time(min) Fig. 5. Effect of alcohol-to-oil molar ratio.

60

100

50

80

40

60

30 40

20

20

10

FFA convertion %

where Si refers to the initial acid value (mg KOH/g oil) and St refers to the acid value at pre-determined reaction time (mg KOH/ g oil). Esterification reactions were conducted using various concentrations of H2SO4 (0.5, 1, 1.5, and 2%) while fish oil to methanol ratio was kept at 6:1 (v/v), and temperature at 60 °C (Fig. 4). It was observed that a conversion of over 80% is obtained in the presence of 1.5% H2SO4 after 180 min. Effect of alcohol-to-oil molar ratio on the FFAs conversion is shown in Fig. 5. Different molar ratios of methanol (6:1, 9:1, 12:1 and 15:1) were used, while other parameters were kept constant (1.5% H2SO4, 60° C, 2 h, and a stirring speed of 700 rpm). It has been observed that maximum conversion of 92.6% was obtained at a molar ratio of 15: 1 within160 min. According to the conditions previously discussed, we traced the reduction of the acid value and the conversion of free fatty acids over time (Fig. 6). It was observed that upon using 1.5% of catalyst, a conversion of 96.03% was obtained, and the FFAs of the oil were reduced to 1.12% of oil. This conversion was confirmed by the disappearance of the band C@O between 1701 and 1721 cm1 in Fig. 3c. To achieve successful alkaline transesterification, 3 mg KOH/g oil may be used as an upper limit for the acid value. This translates to 1.5% (FFAs) in the fish oil [11].

90

FAA conversion %

In the above equation, S is the acid value (mg KOH/g acidified oil), NKOH is normality of KOH, VKOH is volume of KOH used for titration, M is average molecular weight of KOH, and moil is initial weight of oil. FFAs conversion is defined as the ratio of acid value variation before and after reaction to acid value of the initial oil. The conversion is calculated according to Eq. (3):

Acid value mg KOH/g oil

4

0

0 0

50

100

150

200

Time(min) Fig. 6. Acidity and the conversion of free fatty acids over time.

other researchers [12]. The later increased in catalyst amount or molar ratio did not increase the yield of ethyl ester because the separation of glycerol became difficult. The excess of alcohol could slightly favor the recombination of esters and glycerol to monoglycerides because their concentration kept increasing during the course of the reaction. Afterwards, the reaction mixture was transferred into a separating funnel and allowed to settle down for 1 h, which resulted in the formation of two layers. The upper layer was methyl esters and the lower layer was glycerol and impurities. Then, the biodiesel was purified using aqueous phosphoric acid solution (4% v/v) and steam bubbling. Methyl esters derived from WFO biodiesel were analyzed by Fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, and the Gas chromatography–mass spectrometry (GC/MS).

40

3.3. Biodiesel properties 20

0.5% H2SO4 1 % H2SO4 1.5% H2SO4 2 % H2SO4

0

0

50

100

150

200

Time(min) Fig. 4. Effect of catalyst amount on conversion of FFAs and reaction time.

The WFO biodiesel was characterized by 1H NMR spectroscopy and its spectrum is shown in Fig. 7a. The strong singlet at 3.6 ppm indicate methyl ester (-CO2CH3) formation. We also observed that the disappearance of the signals at 4.1–4.3 ppm might indicate the disappearance of the protons attached to the glycerol moiety of mono-, di-, or triacylglycerols. The signals at 2.2 ppm result from the protons on the CHl groups adjacent to the methyl or glyceryl ester moieties (-CH2CO2CH3 for methyl esters). These signals can

Please cite this article in press as: K. Kara et al., Biodiesel production from waste fish oil with high free fatty acid content from Moroccan fish-processing industries, Egypt. J. Petrol. (2017), http://dx.doi.org/10.1016/j.ejpe.2017.07.010

5

K. Kara et al. / Egyptian Journal of Petroleum xxx (2017) xxx–xxx Table 2 Reaction conditions and conversion of methyl esters derived from the WFO. Experiment

Reaction conditions

1 2 3 4 5 6 7 8 9 10

Conversion (%)

Molar ratio methanol:oil

Catalyst (wt%)

Reaction time (h)

Temperature (°C)

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

0.5 0.75 1 0.75 1 1.5 0.5 0.75 1 1.5

2 2 2 1.5 1 1 1.5 1.5 1 1

60 60 60 60 60 60 60 60 60 60

70 80 86 88 99.1 98.6 96 96.5 92.5 92.1

The bold values indicates that best conditions of the conversion of methyl esters.

3000

0,016 1735,5

2000

Absorbance (A.U)

Intensity (A.U)

2500

1500 1000 500 0 8

7

6

5

4

ppm

3

2

1

1168 1354

2851,7

0,012

718 1442

3010,78

0,010 4000

0

2929,4

0,014

3500

3000

2500

2000

1500

Wavenumbers Cm

1000

500

-1

1

Fig. 7a. H NMR spectrum of WFO biodiesel. Reaction conditions: 1% wt KOH and 9:1 M ratio.

Fig. 8. Infrared spectrum of WFO biodiesel. Reaction conditions: 1% wt KOH and 9:1 M ratio.

0 200

150

100

ppm

50

C22:0

C14:0

20000

C20:0

40000

C18:2 C18:3

C18:0

60000

C16:0 C16:1

Intensity(mv)

Intensity(A.U)

80000

C18:1

100000

0

Fig. 7b. 13C NMR spectrum of WFO biodiesel. Reaction conditions: 1% wt KOH and 9:1 M ratio.

be used for quantitation using the Eq. (1) as described before. Other chemical shifts occurred at 5.258, 5.277, and 5.282 ppm in the form of triplet which were characteristics of olefinic protons. The percentage conversion of triglycerides to corresponding methyl esters was 100%. The biodiesel obtained from waste fish oil was also studied by the 13C-NMR spectrum with Deuterated chloroform (CDCl3) as a solvent (Fig. 7b), which shows the characteristic peaks of ester car-

16

18

20

22

24

26

28

30

Time(min) Fig. 9. GC analysis of WFO biodiesel. Reaction conditions: 1% wt KOH and 9:1 M ratio.

bonyl (COO) and CAO at 173.96 and 51.17 ppm, respectively. The peaks around 131.88 and 127.08 ppm indicated the unsaturation in methyl esters. Other peaks at 14 ppm are due to terminal carbon of methyl groups, and signals at 27–34 ppm are related to methylene carbons of long carbon chain in fatty acid methyl esters

Please cite this article in press as: K. Kara et al., Biodiesel production from waste fish oil with high free fatty acid content from Moroccan fish-processing industries, Egypt. J. Petrol. (2017), http://dx.doi.org/10.1016/j.ejpe.2017.07.010

6

K. Kara et al. / Egyptian Journal of Petroleum xxx (2017) xxx–xxx Table 3 Characteristics of produced WFO biodiesel. Characteristics

Methods

Results

Specification NF EN 14214

Ester content (%m/m) Density at 15 °C (kg/l) Viscosity at 40 °C (mm2/s) Flash point PM(°C) Water KF (Mg/kg) Acid value (mgKOH/g) Iodine value (g I2/100 g) Methanol content (%m/m) Free glycerol content (%m/m) Monoglyceride content (%m/m) Diglyceride content (%m/m) Triglyceride content (%m/m) Total glycerol content (%m/m)

EN EN EN EN EN EN EN EN EN EN EN EN EN

95.1 0.883 3.95 104.0 1413 0.16 119 0.01 0.015 0.40 0.10 0.12 0.635

Min 96.5 0.860–0.900 3.50–5.00 Min 101 To report Max 0.50 Max 120 Max0.20 Max 0.02 Max 0.80 Max 0.20 Max 0.20 Max 0.25

14103:2011 ISO 12185 ISO 3104 ISO 2719 ISO 12937 14104 14111 14110 14105 14105 14105 14105 14105

(FAMEs). These results are similar to those found by Tariq et al. [19]. The infrared spectrum of WFO biodiesel (Fig. 8) showed the presence of band located at 3010.9 cm1 due to the stretching vibration of the cis olefinic CH double bond (cis C@CH). The bands at 2929.4 cm1 and 2851.7 cm1 are assigned to the symmetrical and asymmetrical stretching vibrations of the saturated carbon– carbon bond (CH2-assymmetric and –CH2-symmetric). The peak of CAO vibration band was observed in the range 1750– 1735 cm1. Biodiesel could be elucidated from the absorption peak at 1442 cm1 corresponding to C@O stretching [20]. The ester carboxyl bond at 1735 cm1 indicates the formation of compounds containing C@O. The presence of alkane group is also analyzed through the corresponding peak value at 719 cm1. GC–MS analysis was used to study the chemical composition of the synthesized biodiesel. (Fig. 9). Each peak corresponds to a fatty acid methyl ester content of the WFO biodiesel. Fatty acid methyl esters analysis by GC–MS shows the presence of palmitic acid methyl ester (C16:0), oleic acid methyl ester (C18:1), Lenoleic acid methyl ester (C18:2), and Linolenic acid methyl ester (C18:3) in the WFO biodiesel. The WFO biodiesel quality was evaluated according to the international standards. The characteristics of the prepared biodiesel were summarized in Table 3.Viscosity is the most important property of biodiesel since it affects the operation of fuel injection equipment at low temperature while increasing viscosity affects the fluidity of the fuel. The determined viscosity of WFO biodiesel was 3.9 mm2/s which is comparable to the specifications standard. The flash point is a parameter which is considered in the handling and safety of fuels and inflammable materials. The flash point of WFO biodiesel is 104 °C, which is higher than specifications standard and higher than these of petro-diesel according to ASTM D975. This indicates that the WFO biodiesel is safer than the petro-diesel. The characteristics of the prepared biodiesel clearly indicated that the synthesized biodiesel almost abides by international standards.

3.4. Cost analysis A economic analysis was performed to compare the costs of waste fish oil biodiesel with that of salmon oil and soybean oil biodiesel [11]. Supposing that the only difference between waste fish, salmon and soybean oil biodiesel plants hardware would be the costs of raw materials used for biodiesel production. At a cost of 0.69 US $/l for waste fish oil biodiesel compared to 1.065, 0.527, and 0.91 US $/l for salmon biodiesel, soybean biodiesel and diesel fuel respectively, it is easy to see why waste fish oil biodiesel blend make good economic sense. Future efforts will focus on assessing.

4. Conclusion It was found that due to the high acid value of fish oil alkalinecatalysed transesterification was not an effective method for producing biodiesel from the waste fish oil. The present study showed that it is possible to produce biodiesel using waste fish oil with high free fatty acid content. The established process comprised a rapid method of purification and an acid esterification pretreatment followed by a basic transesterification. However, the results indicated that maximum conversion of FFAs was obtained with 1.5% H2SO4 and 15: 1 methanol to oil molar ratio in 160 min.1% KOH was the optimal base concentration, a 9: 1 was the best molar ratio of methanol, 60 °C was the optimal temperature, and a duration of 1 h was enough to give the highest conversion of biodiesel. The 1H-NMR, 13C-NMR, FTIR, and gas chromatography analyses of the final product confirmed that the reaction was total, the biodiesel did not contain any trace of glycerol, and it meets the required international standards. Acknowledgements The authors acknowledge Hassan II Academy of Sciences and Technology for the financial support kindly provided to this research the Kilimanjaro Environment company for logistic assistance.Our thanks go also to the UTRAS-CNRST for the offered open access to its facilities to perform NMR analysis. References [1] FAO, The State of World Fisheries and Aquaculture, Rome, 2014, p. 255. Available from: . [2] M. Afilal, O. Elasri, Z. Merzak, J. Mater. Environ. Sci. 5 (2014) 1160–1169. [3] C.P. Zuta, B.K. Simpson, H.M. Chan, L. Phillips, J. Am. Oil Chem. Soc. 80 (2003) 933–936. [4] A. Amin, A. Gadallah, A.K. El Morsi, N.N. El-Ibiari, G.I. El-Diwani, Egypt. J. Pet. 25 (2016) 509–514. [5] R. Behçet, Fuel Process. Technol. 92 (2011) 1187–1194. [6] S. Godiganur, C. Suryanarayana Murthy, R.P. Reddy, Renewable Energy 35 (2010) 355–359. [7] F. Ouanji, M. Nachid, M. Kacimi, L.F. Liotta, F. Puleo, M. Ziyad, Chin. J. Chem. Eng. 24 (2016) 1178–1185. [8] C.E.D. Santos, J.D. Silva, F. Zinani, P. Wander, L.P. Gomes, Renewable Energy 80 (2015) 331–337. [9] L. Cherng-Yuan, L. Rong-Ji, Fuel Process. Technol. 90 (2009) 130–136. [10] P. Jayasinghe, K. Hawboldt, Renewable Sustainable Energy Rev. 16 (2012) 798– 821. [11] H.M. El-Mashad, R. Zhang, R.J. Avena-Bustillos, Biosyst. Eng. 99 (2008) 220– 227. [12] J.M. Encinar, N. Sanchez, G. Martinez, L. Garcia, Bioresour. Technol. 102 (2011) 10907–10914. [13] I.K. Hong, J.W. Park, S.B. Lee, J. Ind. Eng. Chem. 19 (2013) 764–768. [14] F. Ma, M.A. Hanna, Bioresour. Technol. 70 (1999) 1–15. [15] M.R. Monteiro, A.R.P. Ambrozin, L.M. Lião, A.G. Ferreira, Talanta 77 (2008) 593–605. [16] G. Knothe, J. Am. Oil Chem. Soc. 78 (2001) 1025–1028.

Please cite this article in press as: K. Kara et al., Biodiesel production from waste fish oil with high free fatty acid content from Moroccan fish-processing industries, Egypt. J. Petrol. (2017), http://dx.doi.org/10.1016/j.ejpe.2017.07.010

K. Kara et al. / Egyptian Journal of Petroleum xxx (2017) xxx–xxx [17] J.F. Costa, M.F. Almeida, M.C.M. Alvim-Ferraz, J.M. Dias, Energy Convers. Manage. 74 (2013) 17–23. [18] R. Yahyaee, B. Ghobadian, G. Najafi, Renewable Sustainable Energy Rev. 17 (2013) 312–319.

7

[19] M. Tariq, S. Ali, F. Ahmad, M. Ahmad, M. Zafar, N. Khalid, M.A. Khan, Fuel Process. Technol. 92 (2011) 336–341. [20] M. Anand, M. Gobalakrishnan, M. Maruthupandy, S. Suresh, Energy and environment, Focus 4 (2015) 47–53.

Please cite this article in press as: K. Kara et al., Biodiesel production from waste fish oil with high free fatty acid content from Moroccan fish-processing industries, Egypt. J. Petrol. (2017), http://dx.doi.org/10.1016/j.ejpe.2017.07.010