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Effects of the use of ultrasonic wav...

Alape Benitez, Fabio.

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Effects of the use of ultrasonic waves on biodiesel production in alkaline transesterification of bleached tallow and vegetable oils: Cavitation model.

紀錄類型:	書目-電子資源 : Monograph/item
正題名/作者:	Effects of the use of ultrasonic waves on biodiesel production in alkaline transesterification of bleached tallow and vegetable oils: Cavitation model./
作者:	Alape Benitez, Fabio.
面頁冊數:	169 p.
附註:	Source: Dissertation Abstracts International, Volume: 65-07, Section: B, page: 3573.
Contained By:	Dissertation Abstracts International65-07B.
標題:	Engineering, Chemical. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3140277
ISBN:	9780496874187

Effects of the use of ultrasonic waves on biodiesel production in alkaline transesterification of bleached tallow and vegetable oils: Cavitation model.
Alape Benitez, Fabio.

Effects of the use of ultrasonic waves on biodiesel production in alkaline transesterification of bleached tallow and vegetable oils: Cavitation model. - 169 p.

Source: Dissertation Abstracts International, Volume: 65-07, Section: B, page: 3573.

Thesis (Ph.D.)--University of Puerto Rico, Mayaguez (Puerto Rico), 2004.

Experiments of biodiesel production via methanolysis were performed at methanol/triglyceride molar ratios of 3, 4.5, and 6 and temperatures of 25°C, 40°C and 60°C; the reaction was monitored by HPLC, X-Ray, and GC-MS until equilibrium. A mathematical model called CAVITATION MODEL was developed to deal with mass transfer aspects of the alkaline transesterification reaction of vegetable oils; a comparison between the cavitation model and diffusion through spherical pores was made. Gas-vapor bubble dynamics for the methanol-soybean oil and methanol-tallow system were examined at 40°C and 42°C, respectively. The Rayleight-Plesset equations were used to describe the isothermal growth and adiabatic collapse of the bubble formed when a field of ultrasound at 20 KHz is applied. Temperatures of 2265 K and 426 K were estimated for a bubble in soybean oil-methanol and tallow-methanol systems, respectively. These "Hot Spots" could be responsible for the increment of the temperature occurred and the acoustic streaming observed during the alkaline transesterification reaction. Also, a diffusion analysis with the pore model was made to predict the concentration profile of the triglycerides within the liquid drops of alcohol created after the collapse of the gas-vapor bubbles; spherical shapes were studied. A computational model was made in MathCad to evaluate the effectiveness at different Thiele modulus values in order to estimate mass transfer coefficients for the most critical conditions of pure diffusion and these coefficients were compared with those found by the cavitation model estimation. Pictures of the reactant system soybean oil-methanol-potassium hydroxide, with the red dyed methanol using phenolphthalein, showed that the alkalinity of the system represented by potassium hydroxide remains in the interface alcohol-oil and then is displaced into the glycerol or down layer. The present study serves as a basis for the analysis of heterogeneous reactions with immiscible liquids using ultrasonic agitation.

ISBN: 9780496874187Subjects--Topical Terms:

1018531
Engineering, Chemical.

Effects of the use of ultrasonic waves on biodiesel production in alkaline transesterification of bleached tallow and vegetable oils: Cavitation model.
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