• Energy Research
• 2021-2025close

AbstractThis study provides a new emphasis for research on the valorization of biowastes into nanocatalyst and biorefineries to be integrated with petroleum bioupgrading and polluted water treatment. The response surface optimized batch transesterification of waste‐frying oil using methanol and sustainable animal bone valorized fluorapatite nanocatalyst (FAP) yielded approximately 97% biodiesel via a pseudo‐second‐order reaction with an efficient rate of 0.48 (mol L−1)−1min−1 and activation energy of 13.11 kJ mol−1. In a pioneering step, by‐products of the starch industry and the biodiesel transesterification process; corn‐steep liquor (CSL 0.2 g L−1) and bioglycerol (6.24 g L−1) as nitrogen and carbon sources, increased the dibenzothiophene biodesulfurization (BDS) efficiency of a novel biodesulfurizing Rhodococcus jialingiae strain HN3 (NCBI Gene Bank Accession No. MN173539) sixfold. Further, upon the application of such bioproducts in a batch BDS process (1/3 petro‐diesel/water) of 96 h; HN3 desulfurized 82.26% of 0.62 wt.% sulfur without affecting the petro‐diesel calorific value. In an attempt to reach zero waste, an auxiliary pioneering step was performed, where the spent waste FAP, after being efficiently used for four successive transesterification cycles, was applied to photo‐remediate 4‐nitrophenol polluted water under UV‐irradiation. Advantageously, the fresh and spent waste FAP recorded the same photodegradation capabilities. Where they obeyed the Langmuir–Hinshelwood kinetic model (R2 ≥ 0.966) recording the same rate constants (kapp 0.032 min−1) and were efficiently reused for four successive polluted‐water treatment cycles. © 2021 Society of Chemical Industry and John Wiley & Sons, Ltd

Biodiesel production using supercritical methanolysis has received immense interest over the last few years. It has the ability to convert high acid value feedstock into biodiesel using a single-pot reaction. However, the energy intensive process is the main disadvantage of supercritical biodiesel process. Herein, a conceptual design for the integration of supercritical biodiesel process with organic Rankine cycle (ORC) is presented to recover residual hot streams and to generate electric power. This article provides energy and techno-economic comparative study for three developed scenarios as follows: original process with no energy integration (Scenario 1), energy integrated process (Scenario 2) and advanced energy integrated process with ORC (Scenario 3). The developed integrated biodiesel process with ORC resulted in electric power generation that has not only satisfied the process electric requirement but also provided excess power of 257 kW for 8,000 tonnes/annum biodiesel plant. The techno-economic comparative analysis resulted in favouring the third scenario with 36% increase in the process profitability than the second scenario. Sensitivity analysis has shown that biodiesel price variation has significant effect on the process profitability. In summary, integrating supercritical biodiesel production process with ORC appears to be a promising approach for enhancing the process techno-economic profitability and viability.

Conventional biodiesel manufacturing uses alcohol as an acyl acceptor, resulting in glycerol as a side product. The increased demand for biodiesel has led to the production of a substantial surplus of glycerol, exceeding the market need. Consequently, glycerol is now being regarded as a byproduct, and in some cases, even as waste. The present study aims to suggest an economically viable and ecologically friendly approach for maintaining the viability of the biodiesel sector. This involves generating an alternative byproduct of higher value, rather than glycerol. Triacetin is produced through the interesterification of triglycerides with methyl acetate, and is a beneficial ingredient to biodiesel, reducing the need for extensive product separation. The primary objective of this research is to improve the interesterification reaction by optimising process parameters to maximise biodiesel production while using sulphuric acid as an economically viable catalyst. The study utilised the Box–Behnken design (BBD) to investigate the influence of various process variables on biodiesel yield, such as reaction time, methyl acetate to oil molar ratio, and catalyst concentration. An optimisation study using Response Surface Methodology (RSM) focused on key process reaction parameters, including the methyl acetate to oil (MA:O) molar ratio, catalyst concentration, and residence time. The best conditions produced a biodiesel blend with a 142% yield at a 12:1 MA:O molar ratio, with 0.1 wt% of catalyst loading within 1.7 h. The established technique is deemed to be undeniably effective, resulting in an efficient biodiesel production process.

Biodiesel has been established as a promising alternative fuel to petroleum diesel. This study offers a promising energy conversion platform to valorise high acidity waste cooking oil (WCO) into biodiesel in a single-step reaction via supercritical methanol. Carbon dioxide (CO2) has been used as a co-solvent in the reaction with a catalytic effect to enhance the production of biodiesel. This work provides an in-depth assessment of the yield of four fatty acids methyl esters (FAME) from their correspondent triglycerides and fatty acids. The effects of four independent process variables, i.e., methanol to oil (M:O) molar ratio, temperature, pressure, and time, have been investigated using Response Surface Methodology (RSM). Four quadratic models have been developed between process variables and the yield of FAMEs. The statistical validation of the predicted models has been performed using analysis of variance (ANOVA). Numerical optimisation has been employed to predict the optimal conditions for biodiesel production. The predicted optimal conditions are at 25:1 M:O molar ratio, 254.7 °C, 110 bar within 17 min resulting in 99.2%, 99.3%, 99.13%, and 99.05% of methyl-oleate, methyl-palmitate, methyl-linoleate, and methyl-stearate yields, respectively. The predicted optimum conditions have been validated experimentally.

The valorisation of lignin is being increasingly recognised to improve the economics of pulp and paper making mills. In the present study, an integrated lignin–glycerol valorisation strategy is introduced with an overarching aim for enhancing the process value chains. LignoBoost kraft lignin was subjected to base-catalysed depolymerisation using glycerol as a co-solvent. The generated bio-oil was used as a renewable additive to biodiesel for enhancing the oxygen stability. The influence of three independent parameters including temperature, time and glycerol amount on lignin depolymerisation was investigated. Response surface methodology was applied to design the experiments and to optimise the process for maximising the yield and antioxidant impact of bio-oil. The results showed that glycerol has a positive qualitative and quantitative impact on the produced bio-oil, where an enhancement in the yield (up to 23.8%) and antioxidant activity (up to 99 min induction period) were achieved using the PetroOxy method (EN16091). The addition of 1 wt% bio-oil on biodiesel led to an improvement in the oxidation stability over a neat sample of up to ∼340%, making it compliant with European standard (EN14214). The proposed process presents a biorefinery paradigm for the integrated utilisation of waste cooking oil, lignin and glycerol.

AbstractNowadays, the intensification of the production of biodiesel from non-edible oil crops is mandatory to overcome petrol-fuel depletion and environmental pollution. For the first time, enhanced biodiesel production from castor oil via rotor–stator hydrodynamic cavitation has been studied in this work. Response surface methodology based on one-factor-at-a-time design of experiments was employed for modelling and optimizing the biodiesel yield and the decrease in feedstock viscosity, density, and total acid number (TAN). The predicted optimum parameters of 8.15:1 methanol:oil (M:O), 1499 rpm, 29.38 min, 48.43 °C, and a KOH catalyst concentration of 0.74 wt.% resulted in a 96% biodiesel yield with a concomitant decrease in viscosity, density, and TAN of approximately 95%, 5.12%, and 90.02%, respectively. According to the results of the breakthrough kinetic calculations, the reaction is pseudo-second order, with the activation energy, frequency factor, and reaction rate constant being 0.23 M−1 min−1, 18.77 kJ/mol, and 6.32 M−1 min−1, respectively. The fuel properties of the produced biodiesel and bio-petro-diesel blends were good, comparable to international standards and the marketed Egyptian petro-diesel.