ABSTRACT
Biodiesel is a good alternative to Petroleum Diesel (PD). The storage of fuel is unavoidable for its future use. The objective of the study was to investigate ultrasonic parameters: viscosity, relaxation time, ultrasonic absorption and Gibb’s free energy for 2-year long-term stored biodiesels and blends with PD. The two biodiesels were Cotton Seed Oil Methyl Esters (CSOME) and Palm Stearin Methyl Esters (PSME). Five biodiesel blends with PD in 10, 20, 30, 40 and 50 volume per cent were studied at the room temperature of 301 K. The fatty-acid profiles were also investigated using GC–MS chromatographic analytical tool and the viscosity was determined using an Ostwald viscometer. Ultrasonic velocity was measured with an ultrasonic interferometer of fixed frequency 2 MHz. The results show that CSOME biodiesel contains 13.47 and 86.53 weight per cent of low molecular weight nonpolar and high molecular weight polar compounds, respectively, and PSME biodiesel with 38.66% and 61.33%, respectively. The measured parameters increased for both the biodiesel blends due to storage. The increase in CSOME blends is more than that in PSME blends. For CSOME blends, highest and lowest changes are 64.28% and 4.48% for 10% volume blend of viscosity and pure CSOME biodiesel of Gibb’s free energy, respectively. In PSME blends, they are 31.25% for 10% volume blend of viscosity and zero for 50% volume blend of Gibb’s free energy. The highest difference occurred for 50% volume blends between old CSOME and PSME blends. From the overall results, it is concluded that variations of the measured parameters strongly depend on the fatty-acid profile of biodiesels due to storage.
Acknowledgments
The authors sincerely thank Professor B. Linga Reddy, Department of Physics, for his technical assistance and guidance in carrying out the investigation using an ultrasonic interferometer. The authors are also thankful to the technical staff of Central Analytical Facility, University College of Technology, Osmania University, Hyderabad, Telangana, India, for their technical support in the GC-MS analysis of CSOME and PSME biodiesels.
Additional information
Notes on contributors
Chittepu Obula Reddy
Chittepu Obula Reddy has completed his M Tech (Biotechnology) from JNTU Hyderabad and Ph D in Biotechnology from JNTU Ananthapur. At present he is working as Assistant Professor in the Department of Biotechnology, Chaitanya Bharathi Institute of Technology, Hyderabad, India. He published 11 papers in various National and International journals and guided 35 graduate projects. He presented one paper in a National conference.
Yanala Srinivasa Reddy
Yanala Srinivasa Reddy has completed M Sc and Ph D in Physics from Osmania University, Hyderabad, India. Now, he is working as Assistant Professor in the Department of Physics, Chaitanya Bharathi Institute of Technology, Hyderabad, India. He published 26 research papers in National and International journals and presented 40 papers in National and International conferences.
Maringanti Subhadra
Maringanti Subhadra has obtained her M Sc and Ph D in Physics from Osmania University, Hyderabad, India. She has published 7 papers in International journals and presented 12 papers in various National and International conferences. Now, she is working as Assistant Professor in the Department of Physics, Chaitanya Bharathi Institute of Technology, Hyderabad, India.
Kurapati Rajagopal
Kurapati Rajagopal has obtained both M Sc and Ph D in Physics from Osmania University, Hyderabad, India. he published 11 papers in various National and International journals and presented 18 papers in National and International conferences. At present, he is working as Assistant Professor in the Department of Biotechnology, Chaitanya Bhrathi Institute of Technology, Hyderabad, India.