DSC studies to evaluate the impact of bio-oil on cold flow properties and oxidation stability of bio-diesel

Natural Antioxidant Extracted Waste Cooking Oil as Sustainable Biolubricant Formulation in Tribological and Rheological Applications

Developing eco-friendly formulations using waste cooking oil as renewable biomass is of great interest and commercial importance in the fuels and lubricant industry. This manuscript reports novel study on preparing a biolubricant formulations as WCO-1, WCO-2 and WCO-3 by blending the curcumin extracted soybean waste cooking oil in three different compositions viz 10%, 20%, 30% v/v with the mineral base oil N-150. Curcumin was extracted as a natural antioxidant in 0.5 wt% waste cooking oil to inhibit thermal oxidation. This study comprises a detailed analysis in terms of tribological, rheological and thermophysical characteristics such as viscosity, viscosity index, pour point and flash point parameters of the biolubricant by standard ASTM methods. Further, tribological and rheological analysis was done by the four-ball wear tester and Anton Paar, MCR-72, respectively. The thermophysical evaluation of WCO formulated biolubricant has shown excellent properties. The viscosity index of the formulated biolubricant increases with an increase in the concentration of waste cooking oil. In contrast, the pour point has also been depressing at lower temperature conditions. Thus, WCO based biolubricant was found to be more effective at extreme temperature conditions than the mineral base oil (N-150). Rheological studies have indicated the non-Newtonian behaviour of the biolubricant with an increase in shear rate. Whereas, tribological analysis demonstrates that wear scar diameter has significantly reduced from 0.685 to 0.573 mm, and the coefficient of friction decreased from 0.117 to 0.080 with respect to the mineral base oil. Thus, a straightforward green approach has been discovered by directly utilizing waste cooking oil for biolubricant formulation.

Locally Sustainable Biodiesel Production from Waste Cooking Oil and Grease Using a Deep Eutectic Solvent: Characterization, Thermal Properties, and Blend Performance

As part of local sustainability efforts, biodiesel was synthesized via transesterification using a deep eutectic solvent (DES) without further washing from on-campus, dining facility waste cooking oil and grease. Before moving forward with repurposing used DES as a solvent in chemistry teaching labs, we determined the suitability of the biodiesel as an alternative fuel blended with diesel to power campus utility vehicles. Biodiesel components were characterized by gas chromatography-mass spectrometry (GC-MS), Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (¹H NMR), viscometer, differential scanning calorimetry (DSC), and evolved gas analysis during pyrolysis with a thermogravimetric analyzer coupled with FTIR (TGA-FTIR). The four major components of fatty acid methyl esters (FAMEs) in the biodiesel were methyl oleate, methyl linoleate, methyl palmitate, and methyl stearate. Kinematic viscosity over typical temperature ranges was within optimal values recommended by the American Biodiesel Standard (ASTM D6751), with a 30:70 biodiesel/diesel blend experimental viscosity of 3.43 cSt at 40 °C and a calculated viscosity of 10.13 cSt at 0 °C. The pure biodiesel's cold-temperature onset of crystal formation is -10.1 °C versus -16.4 °C for a 30:70 biodiesel/diesel blend. Pyrolysis indicates good thermal stability, however, with an increased CO₂ evolution in the blended fuel at higher temperatures as compared to that in the pure biodiesel and the pure diesel. Combustion gas analysis indicates virtually complete combustion of the blended fuel to CO₂ and H₂O with only trace amounts of CO. Overall results indicate that the biodiesel synthesized using DES is a suitable fuel for campus utility vehicles in the local moderate temperature climate and affords increased local sustainability by using used DES repurposed in our chemistry teaching labs.

Poly(vinyl chloride) Composites with Raspberry Pomace Filler

This study examined, the effect of chemically extracted raspberry pomace on the thermal stability, mechanical properties, flammability, chemical structure and processing of poly(vinyl chloride). It was observed that the pomace in this study was used to extract naphtha, thereby permitting the removal of bio-oil as a factor preventing the obtaining of homogeneous composites. Furthermore, adding 20% raspberry pomace filler after extraction extended the thermal stability time for the composites by about 30%. It was observed that composite density, impact strength, and tensile strength values decreased significantly with increasing concentrations of filler in the PVC matrix. At the same time, their modulus of elasticity and Shore hardness increased. All tested composites were characterized by a good burning resistance with a flammability rating of V0 according to the UL94 test. Adding 20 to 40% of a natural filler to the PVC matrix made it possible to obtain composites for the production of flame resistant elements that emitted less hydrogen chloride under fire conditions while ensuring good rigidity.

Development of 8 ton/day gasification process to generate electricity using a gas engine for solid refuse fuel

An 8 ton/day solid refuse fuel gasification process with air oxidant was operated under various conditions to generate electricity. Solid refuse fuels with fluff type feedstock were fabricated from municipal solid wastes. The tested experimental conditions included feedstock charging rate into the gasifier, equivalence ratio, and oxygen enrichment; varying these conditions resulted in different gasification characteristics, such as cold gas efficiency and carbon conversion ratio. Optimum conditions were a charging rate of 50 to 60% by volume (504.71 to 605.65 kg/Sm²) of feedstock in the gasifier, equivalence ratio of 0.21 to 0.33, and no oxygen enrichment. Average cold gas efficiency and carbon conversion ratio were 71.30% and 72.07%, respectively, at optimum conditions. Pollutants such as dust, tar, and gases, were analyzed at the outlet of the cleaning facility and gasifier, and their low concentrations in the producer gas were sufficient to allow for operation of the gas engine. The gasification process exhibited stable operation over 288 h, which included the facility check period. The average gasifier temperature was 825 °C, 17.14% by volume of producer gas was syngas, and gas engine power generation was 235 kWh during this period; power consumption of the entire system was 68 kWh. These results demonstrate that the gasification process for converting solid waste to energy can be operated at a commercial scale.

On the study of cucurbit[6]uril and 4-tert-butylcalix[6]arene as multifunctional lubricant additives

Cucurbit[6]uril and 4-tert-butylcalix[6]arene are found to be efficient multifunctional lubricant additives.

Conversion of poplar into bio-oil via subcritical hydrothermal liquefaction: Structure and antioxidant capacity

Subcritical hydrothermal liquefaction of poplar was performed at 220-280 °C, and the liquid phase produced was extracted by ethyl acetate to obtain light oil (LO), which contained LO1 (water-soluble) and LO2 (ethyl acetate-soluble). The residue was further extracted with acetone to produce heavy oil (HO) and solid residue (SR). The highest bio-oil yield of 19.88% was obtained at 260 °C. The HO produced at 260 °C had the highest content of C (69.13%) and the higher heating value was 27.97 MJ/kg. The O/C and H/C ratios of LO were higher than those of HO due to less aromatics in LO. Oxidative inhibition rates of bio-oils, measured in DPPH-ethanol solution at a concentration of 0.1 mg/mL, reached 60.76% for LO1 while 90.29% and 90.85% for LO2 and HO, respectively. The bio-oil with good antioxidant activity can be utilized as an additive in bio-diesel to improve oxidation stability.

Effects of Oxygen Enrichment in Air Oxidants on Biomass Gasification Efficiency and the Reduction of Tar Emissions

This study applied oxygen-enrichment conditions to remove tar (the main problem in biomass gasification) and increase gasification efficiency. Experiments on oxygen-enrichment conditions were conducted at oxygen concentrations of 21%, 25%, 30%, and 35% in oxidants. This was expected to increase the partial oxidation reaction in gasification reactions, thus leading to thermal decomposition of tar in producer gas. The decomposed tar was expected to be converted into syngas or combustible gases in the producer gas. The results were as follows: Tar-reduction efficiency was 72.46% at 30% oxygen enrichment compared to the standard 21% enrichment condition. In addition, the concentrations of syngas and combustible gases in the producer gas tended to increase. Therefore, the 30% oxygen-enrichment condition was optimal, resulting in 78.00% for cold gas efficiency and 80.24% for carbon conversion efficiency. The application of oxygen enrichment into the lab-scale gasification system clearly reduced the concentration of tar and tended to increase some indexes of gasification efficiency, thus suggesting the usefulness of this technique in large-scale biomass gasification operations.

Analysis of thermal stability and lubrication characteristics of Millettia pinnata oil

Lubricants are mostly used to reduce the friction and wear between sliding and metal contact surfaces, allowing them to move smoothly over each other.

Study on the performance mechanism of methacrylate pour point depressant in soybean biodiesel blends

The cold flow properties of soybean biodiesel blends with 0# diesel and methacrylate pour point depressant (10-320) were investigated in this study.

Oxidation stability of biodiesel fuels and blends using the Rancimat and PetroOXY methods. Effect of 4-allyl-2,6-dimethoxyphenol and catechol as biodiesel additives on oxidation stability

IN THE PRESENT WORK, SEVERAL FATTY ACID METHYL ESTERS (FAME) HAVE BEEN SYNTHESIZED FROM VARIOUS FATTY ACID FEEDSTOCKS: used frying olive oil, pork fat, soybean, rapeseed, sunflower, and coconut. The oxidation stabilities of the biodiesel samples and of several blends have been measured simultaneously by both the Rancimat method, accepted by EN14112 standard, and the PetroOXY method, prEN16091 standard, with the aim of finding a correlation between both methodologies. Other biodiesel properties such as composition, cold filter plugging point (CFPP), flash point (FP), and kinematic viscosity have also been analyzed using standard methods in order to further characterize the biodiesel produced. In addition, the effect on the biodiesel properties of using 4-allyl-2,6-dimethoxyphenol and catechol as additives in biodiesel blends with rapeseed and with soybean has also been analyzed. The use of both antioxidants results in a considerable improvement in the oxidation stability of both types of biodiesel, especially using catechol. Adding catechol loads as low as 0.05% (m/m) in blends with soybean biodiesel and as low as 0.10% (m/m) in blends with rapeseed biodiesel is sufficient for the oxidation stabilities to comply with the restrictions established by the European EN14214 standard. An empirical linear equation is proposed to correlate the oxidation stability by the two methods, PetroOXY and Rancimat. It has been found that the presence of either catechol or 4-allyl-2,6-dimethoxyphenol as additives affects the correlation observed.

Fermentation of levoglucosan with oleaginous yeasts for lipid production

This paper reports the production of lipids from non-hydrolyzed levoglucosan (LG) by oleaginous yeasts Rhodosporidium toruloides and Rhodotorula glutinis. Enzyme activity tests of LG kinases from both yeasts indicated that the phosphorylation pathway of LG to glucose-6-phosphate existed. The highest enzyme activity obtained for R. glutinis was 0.22 U/mg of protein. The highest cell mass and lipid production by R. glutinis were 6.8 and 2.7 g/L, respectively from pure LG, and 3.3 and 0.78 g/L from a pyrolytic LG aqueous phase detoxified by ethyl acetate extraction, rotary evaporation and activated carbon. This corresponded to a lipid yield of 13.5 wt.% for pure LG and only 3.9 wt.% for LG in pyrolysis oil.

Detoxification and fermentation of pyrolytic sugar for ethanol production

The sugars present in bio-oil produced by fast pyrolysis can potentially be fermented by microbial organisms to produce cellulosic ethanol. This study shows the potential for microbial digestion of the aqueous fraction of bio-oil in an enrichment medium to consume glucose and produce ethanol. In addition to glucose, inhibitors such as furans and phenols are present in the bio-oil. A pure glucose enrichment medium of 20 g/l was used as a standard to compare with glucose and aqueous fraction mixtures for digestion. Thirty percent by volume of aqueous fraction in media was the maximum additive amount that could be consumed and converted to ethanol. Inhibitors were removed by extraction, activated carbon, air stripping, and microbial methods. After economic analysis, the cost of ethanol using an inexpensive fermentation medium in a large scale plant is approximately $14 per gallon.

Natural and synthetic antioxidant additives for improving the performance of new biolubricant formulations

Knowledge of the oxidative stability of vegetable oils for lubricant applications is a key point, because vegetable oil oxidation potential is the main disadvantage for its use as a lubricant. Oil degradation after an oxidation process can seriously affect its lubricating function and increase wear. In this work, two different methods for evaluating the oxidation stability of lubricating vegetable oils, the oxidation onset temperature, characterized through DSC measurements (ASTM E 2009-08), and the pressure drop in the oxygen pressure vessel (ASTM D 942-02), have been used. Additionally, thermogravimetric analysis and FTIR studies have also been carried out. High-oleic sunflower (HOSO) and castor (CO) oils were selected and blended with natural ((+)-α-tocopherol (TCP), propyl gallate (PG), l-ascorbic acid 6-palmitate (AP)) or synthetic antioxidants (4,4'-methylenebis(2,6-di-tert-butylphenol) (MBP)), with the aim of formulating biodegradable vegetable-based lubricants according to REACH regulation. (1) The results showed that the most effective biodegradable antioxidant is PG, comparable to MBP, whereas lower effectiveness was obtained for TCP and AP. In relation to the methods tested, DSC measurements achieve accurate data more quickly for evaluating the oxidation stability of these basestocks, showing a linear correlation with the traditional method based on the oxygen bomb test. The empirical equation obtained depends on the mechanism involved in the antioxidant activity.