ระบบผลิตไบโอดีเซลจากส่วนกลั่นกรดไขปาล์มแบบต่อเนื่องด้วยเครื่องปฏิกรณ์ท่อผสมแบบสถิตร่วมกับคลื่นเสียงอัลตราโซนิก

Abstract

In this research, the continuous biodiesel production process from palm fatty acid distillate (PFAD) was studied using static mixer coupled with ultrasonic irradiation. The PFAD is a by-product of low market value from the physical refining of crude palm oil (CPO) to edible grade refined palm oil (RPO). The PFAD is not of edible grade, and it is normally used in making soap or animal feed, or by oleochemical industries in general. It can also be used as raw material by the health food and the pharmaceutical industries, as vitamin E can be extracted from PFAD. The PFAD mainly consists of FFA (90.57 wt.%) and it is a promising feedstock for biodiesel production as a potential feedstock for biofuels. Moreover, PFAD is cheaper than the edible oils such as crude palm oil, coconut oil and soybean oil. The ultrasound was assisted the mixing of immiscible liquid for biodiesel production by sonochemical effects on reaction. It was applied in the biodiesel production to decrease reaction time, decrease chemical reactants, and increase yield of biodiesel. In the experiment setup, 5 m of static mixer length was installed for premixing the PFAD, methanol, and sulfuric acid, subsequently, the mixtures were flowed through the ultrasonic tubular reactor (US). The US consisted of 16 units ultrasound clamps attached. Each clamp was operated at fixed frequency of 20 kHz with maximally 400 W power in this study. The ultrasound clamps were fixed in sequence along the length of the reactor at locations 100 mm apart. The ultrasonic power provided maximally 16x400 W input from ultrasonic generator to the ultrasound clamps, for a sum total of 6400 W at full ultrasonic power. The three steps for continuous biodiesel production process from PFAD were esterification first, esterification second, and transesterification third, and these were optimized using models fit by the response surface methodology (RSM) with central composite design (CCD). The manipulated variables: methanol content, catalyst amount, and length of US reactor were optimized the ester purity using RSM. For the 12-step esterification, the ranges of variables: methanol content (19.8-70.2 vol.%), sulfuric acid (0-10.0 vol.%), and length of US reactor (100-700 mm), were studied. The results showed that 60.24 nd wt.% of methyl ester and 103.93 vol.% of yield were achieved under the condition was 45.7 vol.% methanol, 7.0 vol.% sulfuric acid and 400 mm length of US reactor (approximately 10.40 s of residence time). For the 2-step esterification, the ranges of variables: methanol content (26.4-93.6 vol.% ), sulfuric acid (0.6-7.4 vol.%), and length of US reactor (100-700 mm), were studied. The results showed that 91.32 wt.% of methyl ester and 107.63 vol.% of yield were achieved under the condition was 59.6 vol.% methanol, 3.1 vol.% sulfuric acid and 400 mm length of US reactor (approximately 10.40 s of residence time). For the 3-step transesterification, the ranges of variables: methanol content (7.9-21.1 vol.%) and potassium hydroxide (1.2- 6.8 g.L1) were studied. The results showed that 97.11 wt.% of methyl ester, 115.71 vol.% of crude biodiesel yield and 91.67 vol.% of biodiesel yield were achieved under the condition was 13.4 vol.% methanol, 4.0 g.L potassium hydroxide and 18.20 s of residence time. The total chemical consumptions of three-step process were 118.7 vol.% methanol, 10.1 vol.% sulfuric acid, 4.0 g.L potassium hydroxide and 39.0 s reaction time. The final 97.11 wt.% ester purity meets the specifications of commercial-based biodiesel, and Moreover, other characteristics of methyl ester is very close to methyl ester specifications of both the specifications of commercial- based biodiesel and biodiesel community for use in an agricultural engine. -1 -1