Biodiesel Production From Waste Materials: Process Development and Performance Evaluation

World energy crisis is a definite truth, and the rising fuel price is evidence of it. Implementation of renewable energy to overcome the energy crisis is essential. The requirement of energy, especially for road transportation sector can meet through renewable energy. Biodiesel is an appropriate alternative of fossil diesel to run an internal combustion engine efficiently. Currently, vegetable oil is the predominantly accepted feedstock for biodiesel around the globe. However, it is not a feasible biodiesel feedstock due to its insufficient availability and potential food security issues. Current research work explored possible potential biodiesel feedstocks, i.e., rice mill waste, sewage sludge, and kitchen food waste. Appropriate lipid extraction process and transesterification method were developed for waste feedstocks such as rice mill waste, sewage sludge, and kitchen food waste. Reaction parameters of lipid extraction and transesterification were optimized through Taguchi optimization technique. Taguchi model improved the lipid yield by 8.5% (dry wt%) and rice bran methyl ester (RBME) yield by 4.3% (dry weight%) as compared to manually obtained maximum yield. The relevance of Taguchi model for optimization of biodiesel production was verified. Impact of raw material processing on biodiesel properties was established. Influence of co-solvent such as methyl tert butyl ether and tetrahydrofuran on transesterification of sewage sludge lipid was demonstrated through Taguchi generated plots. The present study also developed a closed vessel microwave irradiation process for rapid formation of fatty acid methyl ester (FAME) from kitchen food waste. Traditional transesterification process face difficulties with sample moisture content. But, modified microwave technique utilizes excess moisture to produce a by-product without interrupting the transesterification process. Significantly less energy consumption of 0.088 kWh per liter FAME production was measured. Maximum FAME yield of 96.89 wt% was achieved at microwave cell pressure: 2.2 MPa, temperature: 170 0C, reaction time: 4 min and catalyst concentration: 0.5 wt% with single phase blend ratio 1:6:30 (oil: co-solvent: methanol). Microwave irradiation method and conventional heating in combination with cosolvent-acid catalyzed transesterification resulted in 2.7 and 2.6 times less energy consumption, respectively than the conventional acid catalyzed transesterification process. Selection of appropriate co-solvent for modified microwave process delivered a novel transesterification byproduct glycerol tert butyl ether (GTBE) instead of traditional glycerol. This GTBE is a potential fuel additive that can boost ignition characteristics during engine analysis. Present work also developed an ultrasonic reactor for biodiesel production. The study introduced the reaction parameter kinematic viscosity that significantly eases the process and accelerates the transesterification duration maximum by 4-5 times for sample with free fatty acid (FFA) content greater than 7%. Ultrasonic irradiation in combination with co-solvent improved the reaction output (95.56%), brought down the catalyst demand and smoothened product separation process. The product separation is much easier and faster than the microwave and conventional transesterification based FAME mixture. Commercialization of this method can be done effortlessly due to the simplicity of method and ability to process a wide range of raw material (in terms of FFA content and kinematic viscosity) with minimal modification to the process. Obtained breakeven price of biodiesel is found to be less than current fossil diesel cost. Performance and emission analysis of produced biodiesel were performed to examine the fuel efficiency. Engine performance and emission properties of sewage sludge-derived biodiesel (SSB) were assessed. Major concern behind SSB implementation is the change in fuel properties with geographical and seasonal variation. However, the current study established the positive aspect of SSB. It contains low polyunsaturated fatty acid irrespective of geography and season. Specifically, fewer C18:2 and C18:3 percentages studied for worldwide SSB assures the fuel of better stability, reduced auto-oxidation, and fewer pollutant emissions. Moreover, SSB can also blend with biodiesel derived from other feedstocks with higher polyunsaturated fatty acids, resulting in reduced auto-oxidation by lowering C18:2 and C18:3 concentrations. Finally, the optimum fatty acid profile was prepared through dual biodiesel blend (biodiesel-biodiesel) to ensure enhanced fuel property for better ignition and reduced carbon monoxide (CO), hydrocarbon (HC) and nitrogen oxide (NOx) emissions. GTBE, the by-product of modified microwave irradiation process was used to prepare blend with biodiesel (GTBE-biodiesel blend). GTBE-biodiesel blend in combination with modified injection pressure resulted with higher brake thermal efficiency than fossil diesel and reported a maximum, 10.5% and 20% reduction in NOx and CO emission, respectively. GTBE as a fuel additive is economical as well as environmentally friendly as it is prepared from the dissociation of methyl term butyl ether, i.e., potentially hazardous to dispose of and banned by some countries. Multi-objective optimization on the basis of ratio analysis method (MOORA) was used to optimize fatty acid profile, GTBE-biodiesel blend proportion and injection pressure for improved engine performance and reduced emission

Taguchi Experiment Design for DES K2CO3-Glycerol Performance in RBDPO Transesterification

Biodiesel production using novel glycerol and potassium carbonate-based catalysts has not been developed under the Taguchi technique. This study aims to determine the most influential parameter in biodiesel production from refined bleach-deodorized palm oil (RBDPO) using DES K2CO3-Glycerol as the novel catalyst. The raw material was subjected to transesterification at the desired reaction parameters estimated by the orthogonal 16-run (L16) approach with 2 levels and 4 factors of the Taguchi technique. Signal-to-noise ratio (SNR) and ANOVA were used to confirm the predicted value. From the results, the catalyst is the most influential variable in the TG value of biodiesel, placed in the first rank of the influence factor. Biodiesel production with a minimum total glycerol value (0.210%) using DES K2CO3-Glycerol as a catalyst is most optimally produced at 95 °C for 4 h and 400 rpm using 30 wt% methanol and 4 wt% catalysts achieved by the Taguchi technique. The biodiesel obtained from RBDPO complies with the required international standards. Doi: 10.28991/ESJ-2023-07-03-018 Full Text: PD

Biorrefinería integral para la producción de aceite microbiano a partir de residuos de la industria agroalimentaria

The current environmental predicament requires the search for renewable and sustainable alternatives to fossil fuels, mainly in the transport sector. Biodiesel may replace diesel fuel using an environmentally friendly and economically efficient process, as long as the raw material employed is low-cost and derived from sustainable sources. Such an alternative feedstock from non-vegetable sources, does not compete with food market or land use sources. Annually, around 1.3 billion tons of food are discarded or wasted. This huge quantity has led researchers to search for new applications for this carbon source. Waste management is one of the most significant challenges of EU policies for the coming decades. Our changing food habits carry an inherent increase in waste nutrients, that are definitely worth recycling. The traditional method of waste management is not adapted to meet future energy and environmental requirements. A food waste-based biorefinery allows new approaches in waste recovery, while improving industrial processes. This PhD thesis is based on a biorefinery concept and takes advantage of each nutrient that composes food waste. Food waste (FW) composition from local catering services was analyzed. The analysis showed a high moisture content, the main components were lipids (25.7-33.2, w/w), starch (16.2-29.4%, w/w) and proteins (18.3- 23.5%, w/w) on a dry basis. Also, a metal profile with Na and Mg as main components was found, followed by trace elements, e.g. Zn or Fe. The variability of samples was studied using various statistical tests, and its relationship with FW typology was elucidated. The combination of both, chemical characterization and statistical study, is revealed as a good decision-making tool for further FW processing and valorization. According to initial characterization analysis, oil included in solid food waste (SFW) was found to be feasible for use to produce biodiesel that meets European biodiesel standard EN 14214. For this purpose, Soxhlet extraction of the lipid fraction of SFW from different restaurants was carried out. Fatty acid composition was analyzed and potential differences concerning the source of SFW were evaluated through principal component analysis. Results showed that fatty acid composition of oils from SFW differs depending on the restaurant, but the range of fatty acid methyl esters (FAME) is similar to that found in vegetable oils, showing a high content of oleic acid (C18:1) and linolenic acid (C18:2). Due to high free fatty acid content, acid esterification pre-treatment was conducted, followed by a basic transesterification optimization, by both conventional and ultrasound (US) assisted reactions. Response surface methodology was selected to perform the experimental design; optimal conditions for conventional transesterification resulted in 93.23% w/w fatty acid methyl esters (FAME) conversion. Several chemical and physical properties of SFW oil biodiesel were analyzed. It was found that biodiesel fulfils the European standard EN 14214, with the exception of FAME yield, oxidation stability and glyceride content. It may be concluded, from this field trial, that oil from SFW from different restaurants may be mixed together and used to produce biodiesel. Finally, oleaginous yeasts were evaluated via hospitality food waste fermentation. In light of the starch and protein content of food waste, controlled enzymatic hydrolysis was considered feasible, and required enzymes may be provided through solid state fermentation (SSF) using A. awamori and potato peel as substrate. Crude hydrolysates were subsequently used in shake flask fermentations, with oleaginous yeast Rhodosporidium toruloides Y-27012, attaining a total dry weight (TDW) of 32.9 g/L and a lipid content within the cells of 36.4 %. Results of R. toruloides fermentations in a fedbath bioreactor showed a TDW of 53.9 g/L and a lipid production of 26.7g/L. Moreover, fatty acid profile of microbial oil from bioreactor samples revealed the presence of palmitoleic acid (C16:0) and oleic acid (C18:1) as main components. The principal component analysis (PCA) performed showed a fatty acid profile similar to soybean or solid food waste oil (SFWO). Finally, recovered microbial oil was transesterified to biodiesel, achieving a yield of 94%, which almost fulfills the European standard normative EN 14212

In situ transesterification of rapeseed for production of biodiesel and secondary products

PhD ThesisIn situ transesterification (IST) can potentially reduce the cost of biodiesel production by avoiding the oil extraction and refining stages of conventional transesterification, through the direct reaction of the oilseed with alcohol in the presence of a catalyst. However, a large excess of alcohol is currently required in IST to achieve comparable yields to conventional transesterification. Hence, in this study, methods for improving in situ transesterification of rapeseed for biodiesel production have been investigated. The focal point of this study is to reduce or utilize the excess alcohol. Pre-soaking seeds in methanol and reactive coupling were subsequently attempted. The respective rationales are to reduce the excess methanol requirement, and convert/use the excess methanol in a secondary process. Pre-soaking involved a chemical pre-treatment of the oilseed prior to the transesterification reaction. Pre-soaking was performed with methanol to oil molar ratio (MOMR) of 360:1 at 60°C using a catalyst (NaOH) concentration of 0.1M. A two-level factorial design was used to determine the optimum conditions for pre-soaking. It was found that a biodiesel yield of 85% was obtained for pre-soaking at 360:1 MOMR while the ‘un-soaked’ biodiesel yield was 75% at 475:1 MOMR. The higher biodiesel yield with 24% reduction in methanol requirement could potentially translate to energy savings in the downstream separation of biodiesel from excess methanol. Reactive coupling (transesterification + a glycerol polymerisation reaction) should increase the equilibrium conversion of biodiesel, whilst generating valuable secondary products. It was carried out in a pressure vessel at 10 bar, 140°C in an inert atmosphere. Polyglycerol was identified in the reaction mixture using FTIR and 1H-NMR. Using a MOMR of 375:1 with catalyst concentration (H2SO4) of 4.8 v/v% at 140°C, a biodiesel yield of 90% and polyglycerol (PG) yield of 10% were observed after 4 hours of reaction. Overall, the material balance indicated that at the end of the reaction, 19% of the unused methanol had been converted to dimethyl ether (DME). This would lead to energy savings in the separation of product. The Central Composite design of experiment for reactive coupling indicated that catalyst concentration was the most significant variable in biodiesel production, whilst molar ratio is significant for both polyglycerol and DME production. Moreover, the study demonstrates the practicality of FTIR online monitoring of IST, which could be valuable for on-line monitoring at industrial scales, where iii traditional off-line GC analysis is time-consuming and ineffective to correct immediate production problems. Furthermore, the online monitoring could be used for “fast IST” of rapeseed to biodiesel to detect the onset of saponification. This work has demonstrated co-production of valuable chemicals with biodiesel production via reactive coupling for the first time. This could be the initial step toward an integrated biodiesel-based bio-refinery.Tertiary Education Trust Fund (Tetfund), Nigeria for providing funding for the programm

Develop an efficient and sustainable process for biodiesel production via transesterfication

In this thesis, metal mixed oxides (Li/TiO2) and chicken bone based catalysts (Li-Cb, Li/Zn-Cb) were prepared by wet impregnation method, characterized by several spectroscopic and analytical techniques, and performed in the transesterfication of fresh and waste canola oil for biodiesel production under different reaction conditions of reaction time, reaction temperature, and methanol to oil molar ratio. The Li/Zn-Cb catalyzed transesterfication process was evaluated under the ultrasonic conditions and optimized by Box Behnken Design (BBD)

Soybean

Soybean is an agricultural crop of tremendous economic importance. Soybean and food items derived from it form dietary components of numerous people, especially those living in the Orient. The health benefits of soybean have attracted the attention of nutritionists as well as common people

Status quo of Biodiesel Production in Africa: A Review on Technological Options, Policies and Aboriginal Feedstock Potential

Growing industrialization, modernization along with better living standards in Africa, are expected to rise in the coming years with energy demand, increasing eventually. This expansion is occurring at a time when oil prices have reached new heights. Unstable oil prices do indeed, increase the vulnerability of importers. However, it also presents an opportunity to explore promising technical options to help reduce the over-reliance on imported petroleum fuels. Biofuels including biodiesel, offer new opportunities for African countries. They can contribute to economic growth, and rural incomes for some countries and provide low cost fuel for others.  In this paper: the importance, properties, vegetable feed-stocks and enhancement in technology for production of biodiesel are described, including; characterization, engine performance, energy actual state, current situation of biodiesel and bioenergy policies in Africa. From the exploration, it is inferred that; there are auspicious oil resources in the plan for biodiesel industrialization in Africa

Experimental Parametric Analysis of Biodiesel Synthesis in Microreactors with Waste Cooking Oil

This study investigates biodiesel synthesis with waste cooking oil using a microchannel device thermally driven using rejected heat through a parallel heat exchange process. Rather than use a resource-intensive full factorial experimental analysis, a partial factorial Taguchi analysis was used to explore parametric effects and greatly reduce the amount of experiments needed. The reduction of free fatty acids in vegetable oil was first studied. While free fatty acid content of the oil was reduced to 0.2%, below the recommended level for transesterification (0.5%), large amounts of emulsions were created during purification which makes the process less feasible for large scale production use. The parametric effects of transesterification were then investigated using purified waste cooking oil. A biodiesel conversion of 98% was achieved which is very close to the industrially acceptable level of conversion. In addition to the high level of conversion, the reaction time of the synthesis was only 2 minutes which is much lower than the reaction times using traditional batch reactors. The analysis suggested that the conversion could be increased with an increase in catalyst concentration.Este estudo investiga a síntese de biodiesel com óleo de cozinha residual usando um dispositivo de microcanais acionado termicamente usando calor rejeitado através de um processo paralelo de troca de calor. Em vez de usar uma análise experimental fatorial completa com uso intensivo de recursos, uma análise fatorial parcial Taguchi foi usada para explorar os efeitos paramétricos e reduzir bastante a quantidade de experimentos necessários. A reduo de ácidos graxos livres no óleo vegetal foi estudada pela primeira vez. Enquanto o teor de ácidos graxos livres do óleo foi reduzido para 0,2%, abaixo do nível recomendado para transesterificação (0,5%), grandes quantidades de emulsões foram criadas durante a purificação, o que torna o processo menos viável para uso em larga escala de produção. Os efeitos paramétricos da transesterificação foram então investigados usando óleo de cozinha residual purificado. Uma conversão de biodiesel de 98% foi alcançada, o que é muito próximo do nível de conversão industrialmente aceitável. Além do alto nível de conversão, o tempo de reação da síntese foi de apenas 2 minutos, o que é muito menor do que os tempos de reação usando reatores tradicionais industriais. A análise sugeriu que a conversão poderia ser aumentada com um aumento na concentração de catalisador

Reactive coupling for biodiesel production with integrated glycerol valorisation

Ph. D. Thesis.The increasing production of biodiesel globally over the last 20 years has increased the supply of “crude” glycerol. Initially, glycerol was a valuable by-product but is now low value or a waste product, due to mismatch between supply and demand. Valorisation of glycerol is an obvious route to improving the process economics. In this work, we investigated glycerols in situ valorisation by conversion to various oligomers (used in the pharmaceutical, food, and cosmetics industries) and glycerol ethers (used as oxygenated compounds to improve fuel combustion in Diesel engines). This is an example of "reactive coupling", a technique in which the by-product of one reaction is simultaneously converted to an added value product in a second reaction (in a single "pot"), thereby reducing the number of process steps. The main objective for this work is to produce glycerol free biodiesel with reduced methanol usage and fast triglyceride conversion using reactive coupling as a novel technique. This work will for the first time demonstrate the production of biodiesel and glycerol ethers in a single pot. This aimed to reduce glycerol byproduct and methanol recycling. First, the study the convert glycerol in a stainless steel reactor. Reactive coupling was then performed to convert triglyceride with simultaneous conversion of the glycerol to added value products. Sulfuric acid was used as catalyst for the reaction, as it is compatible with all the desired reactions. It is also cheap and can tolerate triglyceride with high FFA levels during biodiesel production. High temperature in transesterification results in fast conversion of triglyceride. The catalyst and temperatures used are suitable for both biodiesel reaction and glycerol etherification. Highest conversion of glycerol achieved was 68%, with over 90% selectivity to diglycerol in 5h. To avoid producing undesired by-products (such as acrolein) and higher oligomers (such as pentaglycerol), the recommended conditions are 3 wt% catalyst concentration, and a temperature of less than 150 oC. Furthermore, a kinetic model was fitted to the experimental data with activation energy of 112 kJmol-1 and pre-exponential factor of 2.18x1011 L.mol-1s-1. The thermodynamic analysis showed the reaction to be endothermic, less disordered, and non-spontaneous with an enthalpy (ΔH) 109 kJmol-1, entropy (ΔS) – 38.1 Jmol-1K-1, and Gibbs free energy (G) 125 kJmol-1 respectively. Reactive coupling achieved complete conversion of triglycerides and 100% FAME yield in 1h. About 60% of the glycerol was converted in parallel, with approximately 90% selectivity to glycerol ether and 10% to diglycerol. A temperature of not more than 150 oC is sufficient for this process with 3 wt% catalyst concentration and molar ratio 4:1 – 6:1. Some of the benefits of the reactively coupled process vs conventional processing are the rapid separation of the biodiesel phase from the glycerol phase, low alcohol to oil ratios, and the production of value-added products from the crude glycerol. The model should make scale-up of this process more predictable and robust. Combined reactive extraction and reactive coupling were also studied, i.e., reactive coupling on the oilseeds, rather than the oil. Over 90% of biodiesel production was achieved and complete conversion of the glycerol to glycerol ether and polyglycerol. However, a substantially higher molar ratio of methanol to oil (400:1) was required, likely to be uneconomic. There were various non-triglyceride products in the extract, which would probably necessitate extra downstream processing. In summary, for the first time, this work demonstrates reactive coupling to produce biodiesel, polyglycerol, and glycerol ether production using sulfuric acid as catalyst. The main advantages of this technique were: i. Reduced glycerol by-product by up to 60%. ii. Reduced methanol usage, from 20:1 to 4:1 – 6:1. This will remove/reduce downstream processing. iii. Rapid conversion of triglyceride. iv. Easy/fast separation of glycerol phase from FAME phase. Furthermore, this study demonstrated proof-of-concept for combined reactive extraction and reactive coupling. Hence, oil in seeds can be converted directly to biodiesel, glycerol, and added-value products. This study’s success shows that the glycerol by-product can be converted to a useful product directly during biodiesel production. Potentially, this will reduce waste generation and diversify the market of biodiesel producers.Petroleum Technology Development Fund (PTDF), Nigeri

Synthesis, Optimization, and Kinetic Studies of Sulfonated Palm Biomass Magnetic Biochar Catalyst for Biodiesel Production Using Used Cooking Oil

Magnetic biochar catalyst (MBC) utilization in biodiesel production can enhance the catalyst separation process and reusability. As MBC utilization is still on the laboratory scale and studies on the utilization of MBC are still limited, many aspects are still unknown. This research addressed the abovementioned research gaps. MBC was synthesized and characterized from oil palm biomass. The optimum MBC synthesis parameters were acquired. Optimized biodiesel production parameters using the synthesized MBC, the biodiesel characteristics, and the reaction kinetics were studied