A novel extractive reactor technology for biodiesel production from waste cooking oil

Biodiesel is touted as potential alternative energy to reduce the over-dependency upon the depleting and hazardous hydrocarbon fuel. The pursuit of a feasible biodiesel technology however still remains due to the feedstock limitations of the conventional inorganic-catalysed methods. The design of a process that is adaptable to the nature of low-grade and non-edible oils or fats such as those using lipase-catalysed process is thus favourable. Therefore, the main thrust of this thesis is to employ a novel extractive basket impeller column (BIC) reactor for the production of biodiesel. Studies on the inherent reaction kinetics of the production of ethyl oleate (key fatty acid ethyl ester (FAEE) from the biodiesel process using bioethanol) by ethanolic esterification and transesterification reactions of oleic acid and waste cooking oil (WCO) respectively, were conducted under monophasic and biphasic (two-immiscible liquid) conditions using Novozym 435 lipase as biological catalyst. Feed reactant-mole ratios and initial water contents were varied. In microaqueous environments, the Ping-Pong-Bi-Bi kinetic model of the esterification reaction revealed an optimum at a stoichiometric mixture of ethanol-oleic acid and was similarly demonstrated in the reaction rate analysis of waste cooking oil transesterification. In biphasic media, the maximum rate was further increased and a sinusoidal trend that was probably attributed to the dynamic ethanol distribution and the conformational change of lipase active site due to water interaction. Interestingly, in the biphasic esterification reaction with simultaneously-varied feed ratios, the optimum was skewed at a 4-fold molar excess of oleic acid. As the reaction rates were enhanced from the use of water probably associated with the positive allosterism of the lipase, the potential of a solvent extraction system using water was consequently investigated using the BIC. Preliminary tests using a single stage operation revealed that besides having an optimum stirring speed, the reaction yield also improved when the viscosity of the substrate was reduced at the same stirring speed, even though viscosity reduction involved the use of ethanol, a competitive inhibitor. This phenomenon is probably due to flow restrictions imposed by the basket mesh on relatively high viscous oily co-reactant. At a stirring speed of 600 rpm and above, a vortex probably formed creating a saturated low-viscous-liquid zone attributed to the swirling ethanol phase as evidenced by a dilatant characteristic of shearing stress during agitation and the subsequent GC analysis. These rheological issues and the probability of vortex formation are influential factors in the extractive reaction using the basket impeller. Reaction rate studies were conducted at different solvent-feed ratios and stirring speeds in a 9-stage BIC column. The Damköhler number obtained was below unity suggesting that the reaction occurred at an excellent extraction condition. Significantly, the efficiency of the column was more than 200% compared to a single stage operation. This study also showed the negative effect of high WCO flow relative to the ethanol aqueous flow and the deterioration effect of stirring at speeds higher than 500 rpm due to the aforementioned vortex appearance. Using the reaction rate data collected at the optimum BIC condition, a fixed capital cost analysis was performed and consequently revealed feasibility of this extractive reaction concept can achieve a 50% reduction in the production cost of 8000 tonnes per annum production

Extraction of Oil from Cocoa Shell Waste by Hydrodistillation using Microwave

Phytosterols are consumed in many pharmacological products. Cocoa shell is an interesting source as its oil extract has high phytosterol content and potential of valorization. This paper reports application of microwave to control rapid heating assisting hydrodistillation (MAE-HD) of cocoa shell waste (CSW) powder. The objectives were to optimize factors to maximize extraction yield and time. Water to CSW ratio, microwave power and extraction time were varied in One-Factor-At-a-Time (OFAT) manner from 2:1 to 10:1, from 180 to 280 W and from 30 to 150 min, respectively using optimum, predetermined factors. Selected range of the factors was further tested in central composite design. The extract was analyzed by using the Liebermann-Burchard method to measure phytosterol amount. From the response surface of CCD, oil extraction was optimal at 225W for 90 minutes with the water-CSW ratio of 7.94:1 with the yield of 2.46 mass% under significant model of surface functions

Kinetic study of ethanol dry reforming using lanthanum copper perovskite

This paper reports the syngas production from ethanol dry reforming reaction for a greener and sustainable process. The aims were to delineate the effect of lanthanum-copper-based perovskite catalyst on the kinetics of the reaction at the temperatures spanning from 725 to 800 °C. The citric sol–gel method was employed to prepare the catalysts by using lanthanum and copper nitrate salts by mixing them based on equal mass of the metals in the desired perovskite structure. The reactions were tested in a tubular reactor using 0.1 of g catalyst between 125 and 160 µm of particle size, which was reduced in-situ by using hydrogen before the reaction. The reactants were mixed in a few carbon dioxide to ethanol molar ratios from 2.5 to 1 and entered the reactor at 1.43 min of space time under atmospheric pressure to ensure the negligibility of mass transport hindrance. At steady states, the products were sampled and analysed in a GC-TCD. The parameters of power law were obtained from reactant consumption against various feedstock flows with R2 > 96% based on differential reactor method. 44.2 kJ /mol of activation energy and other rate constants were obtained

Synergistic effect of molybdenum disulphide and butylated hydroxytoluene in lithium complex grease

Lubricating grease is vital as a sealant and provides extra protection for automotive parts, such as bearings. Bearings are subjected to friction and sliding wear, which results in the degradation of automotive or machinery performance. The present article analysed the effect of molybdenum disulphide (MoS2) and butylated hydroxytoluene (BHT) as grease additives in reducing the frictional and wear behaviour of steel ball bearings. The experiment was conducted by preparing two formulated lithium complex-based grease with a different blending of additives of BHT only (LCG 01/18) and MoS2 + BHT (LCG 01/5). The formulated greases were compared with two industrial greases as the controlled parameters. Next, the physical characterization of formulated and industrial greases was conducted which includes dropping point test (ASTM D2265-00), cone penetration test (ASTM D217-02) and oil separation test (ASTM D6184-17). Then, the four-ball test (ASTM D2266-01) was performed to identify the effect of additives on the wear and frictional coefficient behaviour. The blending of MoS2 and BHT improves the physical characterization of grease in terms of dropping point and oil separation. The blending of MoS2 and BHT also helps to decrease the wear diameter and frictional coefficient. Nonetheless, further study is desired to gain a thorough understanding of the processes so that an optimal system can be developed for the industry

Grease Quality Issues on Middle Voltage Switchgear: Corrosivity, Resistivity, Safety and Ageing

Grease products recommended by OEM for conventional 11kV switchgears are generally trusted. Some disadvantages might however exist among them or their supply could be insufficient and lead to use of non-OEM-recommended grease. This paper reports analysis methods to evaluate both types of grease that were recently used in the switchgears at local electrical distribution stations owned by Tenaga Nasional Berhad. Hardened, greenish and severely irritating greases probably caused by incompatible compounding, electrochemical reaction, and hazardous components, respectively, were among common problems faced by workers. Eight physical tests and four chemical tests were conducted on 10 grease samples using thermogravimetry, switchgear rig, gas chromatography and infrared spectroscopy besides other equipment and standard methods. Grease stability, oil bleeding, flammability of grease droplet and dropping point were among the characteristics determined in the analyses. The results reveal copper corrosion, chemical change, instable and inconsistent grease, and toxics in grease, which surprisingly included the OEM-recommended one. ABSTRAK: Produk gris yang disyorkan oleh Pengeluar Peralatan Asal (OEM) bagi gear-suis konvensional 11 kV secara umumnya dipercayai ramai. Kemungkinan terdapat kekurangan pada produk-produk tersebut ataupun bekalan gris mereka yang tidak mencukupi telah mendorong kepada penggunaan gris yang tidak disyorkan oleh OEM. Kaedah analisis kajian ini melaporkan tentang kedua-dua jenis gris yang kebelakangan ini digunakan oleh Tenaga Nasional Berhad pada gear-suis di stesen pencawang elektrik. Gris mengeras, berlumut dan menjengkelkan mungkin disebabkan oleh sebatian bahan yang tidak sesuai, tindak balas elektrokimia dan komponen yang tidak selamat, masing-masing adalah antara masalah yang dihadapi oleh para pekerja. Lapan ujian fizikal dan empat ujian kimia telah dijalankan pada 10 sampel gris menggunakan termogravimetri, pemakai gear-suis, kromatografi gas dan spektroskopi inframerah selain alatan lain dan kaedah-kaedah piawai. Antara ciri-ciri yang dikaji dalam analisis ini adalah kestabilan gris, sifat lelehan minyak, sifat mudah terbakar titisan gris dan takat rendah gris. Hasil kajian mendapati gris ini menyebabkan tembaga terhakis, sifat kimia berubah, sifat gris yang tidak stabil dan mudah berubah, dan juga beracun memberi kejutan kerana pihak OEM tetap mengesyorkan gris jenis ini

Enzymatic Conversion of Glycerol to Glyceric Acid with Immobilised Laccase in Na-Alginate Matrix

AbstractIn this study, enzymatic oxidation of glycerol was performed for the production of glyceric acid. The effectiveness of immobilised laccase in Na-Alginate matrix was also verified. Glycerol was incubated at 25oC with 30mM of 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO), which acted as a mediator, in the presence of immobilized laccase from Trametes versicolor. Glyceric acid was quantified using HPLC, while the activity of enzyme was measured using ABTS assay. The yield of laccase activity was 90%. On the other hand, glyceric acid obtained was around 7 wt% from the total product at 24h. In conclusion, enzymatic oxidation is able to produce comparable amount of glyceric acid through a more environmental friendly method

Formulation and Characterization of Cu-Zn-V-Al Oxides Catalyst in Auto Thermal Reforming of Methanol.

Nowadays the world concern about the alternative solutions to the combustion engine due to the problem of the decreasing resources of crude oil and its recent environmental impact. One of the attention that are paid by most of the automotive industries is proton exchange membrane fuel cell (PEMFC). To comply with the modern automobiles a fast and highly responsive supply of hydrogen with no byproduct other than carbon dioxide must be found. The high selectivity requirement emanate from the sensitivity of the PEM containing Pt as the catalyst for proton exchange

Preliminary assessment on pretreatment methods for landfill waste utilization in biohydrogen production

Landfill waste consists of a mixture of components that have high potential as a substrate for hosting various microorganisms’ growth. Utilizing this waste as a fermentation substrate is seen as an economical solution for the management of the waste. Treating this waste is crucial to remove unnecessary components for the growth of specific organisms to ensure a high reaction yield. Fermentative hydrogen production from this waste specifically requires the hydrogen-consuming bacteria to be reduced. In this work, heat, ultraviolet (UV) radiation, acid, and alkaline pretreatment were conducted on the landfill waste. The changes in the reduced sugar content and appearance of bacterial colonies were observed and compared. Heat pretreatment at 65 °C was found to give among the best increase (74 – 88%) in reducing sugar content and reduction (50 – 85%) in the number of aerobic bacterial colonies detected. Global warming potential and eutrophication potential recorded from simulated heat pretreatment plant was comparable to other heat-based pretreatment reported by other researchers with a potential reduction in severity as the plant size increased