Separation process is very crucial in bioethanol production as it consumes the highest energy in the process. Unlike other works, this research systematically designed a suitable separation process for bioethanol production from corn stover by using thermodynamic insight. Two separation processes, i.e., extractive distillation (case 2) and pervaporation (case 3), were developed and compared with conventional molecular sieve (case 1). Process design and simulation were done by using Aspen Plus program. The process evaluation was done not only in terms of energy consumption and process economics but also in terms of environmental impacts. It was revealed that pervaporation is the best process in all aspects. Its energy consumption and carbon footprint are 60.8 and 68.34% lower than case 1, respectively. Its capital and production costs are also the lowest, 37.0 and 9.88% lower than case 1.

CO₂ methanation was studied over monometallic catalyst, i.e., Ni, Fe and Co; on CeO₂-Cr₂O₃ support. The catalysts were prepared using one-pot hydrolysis of mixed metal nitrates and ammonium carbonate. Physicochemical properties of the pre- and post-exposure catalysts were characterized by X-Ray Powder Diffraction (XRD), Hydrogen Temperature Programmed Reduction (H₂-TPR), and Field Emission Scanning Electron Microscope (FE-SEM). The screening of three dopants over CeO₂-Cr₂O₃ for CO₂ methanation was conducted in a milli-packed bed reactor. Ni-based catalyst was proven to be the most effective catalyst among all. Thus, a group of NiO/CeO₂-Cr₂O₃ catalysts with Ni loading was investigated further. 40 % NiO/CeO₂-Cr₂O₃ exhibited the highest CO₂ conversion of 97.67% and CH₄ selectivity of 100% at 290 °C. The catalytic stability of NiO/CeO₂-Cr₂O₃ was tested towards the CO₂ methanation reaction over 50 h of time-on-stream experiment, showing a good stability in term of catalytic activity.

By-product upgrading is crucial in hydrocarbon processing industries as it can increase the competitiveness of the business. This research investigated opportunity to upgrade fuel oil by-product obtained from olefins production by using microwave pyrolysis. A lab-scale quartz reactor filled with placed inside a 1,200 watts household microwave oven was used for the experiments. Coconut-based activated carbon was used as a microwave receptor. Microwave powers were varied at 600 W, 840 W and 1,200 W to adjust cracking temperature between 800°C and 900°C. The effect of residence time was investigated by adjusting flow rate of N2 carrier gas. The chemical compositions and product yields were analyzed by using gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS). It was revealed that hydrogen, carbon monoxide, carbon dioxide and hydrocarbon gaseous product (alkanes, naphthenics and alkenes) were produced as the main products. For liquid products, the main compositions were cycloalkenes and polycyclic aromatic groups.