Commissioning of Biogas Reactor

Biogas reactors can utilize food waste as substrate to produce methane, which can be used as a source of energy. In addition, fertilizer can be obtained after anaerobic digestion of the waste. Thus, nowadays many organizations in Finland are establishing biogas reactors in their facilities to utilize their waste for obtaining energy. These reactors also follow the module of circular economy, which is a thriving environmental sustainability practice. Metropolia, Myyrmäki Campus is joining the bandwagon by establishing a HomeBiogas reactor in their premises to utilize food waste from the university canteen. The purpose of this thesis was to ensure safety and proper functionality of the reactor being installed. This thesis investigates the parameters for optimum biogas production from the reactor with the help of various literatures. It also predicts the amount of biogas that can be produced in the University with the help of Buswell equation. As safety is an important aspect in any biogas system, a risk analysis of the potential hazards has been done. Installation of various sensors are discussed as safety mechanism to minimize hazard risks, due to leaks from the system. This thesis also recommends type of food waste that should be fed into the digester for maximum biogas output

Interactions between Iron and Nickel in Fe–Ni Nanoparticles on Y Zeolite for Co-Processing of Fossil Feedstock with Lignin-Derived Isoeugenol

A set of low-cost monometallic Fe, Ni, and bimetallic Fe–Ni bifunctional H–Y-5.1 catalysts with different metal ratios were synthesized by sequential incipient wetness impregnation. The catalysts were characterized in detail by N$_2$ physisorption, Fourier transform infrared spectroscopy with pyridine, inductively coupled plasma optical emission spectroscopy, X-ray diffraction (XRD), transmission and scanning electron microscopy (TEM–SEM), magic angle spinning nuclear magnetic resonance, X-ray photoelectron spectroscopy (XPS), Mössbauer spectroscopy, magnetic measurements, temperature-programmed reduction (TPR), and X-ray absorption spectroscopy (XAS). The results revealed that introduction of Fe led to a decrease of strong acid sites and an increase of medium Brønsted acid sites, while introduction of Ni increased the number of Lewis acid sites. The particle size of iron was approx. 5 nm, being ca. fourfold higher for nickel. XPS demonstrated higher iron content on the catalyst surface compared to nickel. Both Mössbauer spectroscopy and magnetic measurement confirmed the ferromagnetic behavior of all catalysts. In addition, the results from XRD, TEM, XPS, XAS, and magnetization suggested strong Fe–Ni nanoparticle interactions, which were supported by modeling of TPR profiles. Catalytic results of the co-processing of fossil feedstock with lignin-derived isoeugenol clearly showed that both product distribution and activity of Fe–Ni catalysts strongly depend on the metals’ ratio and their interactions. Key properties affected by the Fe–Ni metal ratio, which played a positive role in co-processing, were a smaller medial metal nanoparticle size (<6 nm), a lower metal–acid site ratio, as well as presence in the catalyst of fcc FeNi alloy structure and fcc Ni doped with Fe

Co-processing of fossil feedstock with lignin-derived model compound isoeugenol over Fe-Ni/H-Y-5.1 catalysts

Co-processing of n-hexadecane with lignin derived isoeugenol as a model compound was investigated in this work using low-cost mono- and bimetallic iron and nickel supported on H-Y-5.1 zeolite. Different Fe-Ni metal ratios in the catalyst led to different reaction rates of processes and product distribution. The presence of just 0.26 wt% isoeugenol in the mixture with n-hexadecane made hydroisomerization-hydrocracking of the latter two-fold less active. Catalysts with smaller metal particle sizes, lower than 6 nm were more efficient pointing out on structure sensitivity. Extremely high activity in co-processing was obtained over 2 wt% Fe – 8 wt% Ni/H-Y-5.1 catalysts with the median metal particle size of 4.6 nm and metals-to-acid site ratio of 8.6. Fe catalyst were much less active in isoeugenol hydrodeoxygenation, while high cracking activity of hexadecane was observed in the presence of Ni. Alkylation of n-hexadecane was a feature of 8 wt% Fe – 2 wt% Ni/H-Y-5.1, whereas, over the 5 wt% Fe – 5 wt% Ni/H-Y-5.1 bifunctional catalyst no undesired oxygen-containing cyclic products were detected. This catalyst exhibited the highest hydrogen consumption according to temperature programmed desorption, which can serve as a marker for efficient hydrodeoxygenation. The spent catalysts contained ca 40 wt% of coke with predominantly aliphatic species

Hydrodeoxygenation of lignin-derived model compound isoeugenol over Fe-, Ni-, and Fe-Ni-supported on zeolites

As the world is transitioning away from fossil fuels, lignocellulosic biomass is scrutinized as a source of renewable fuels and chemicals. Political motivations and environmental concerns have increased the research in lignin, an underutilized resource currently, as a potential source of bio-oils. These bio-oils cannot be used in the existing petroleum-based infrastructures due to their high oxygen content and complex structures. Hence, catalytic hydrodeoxygenation could be used to reduce the oxygen content of the bio-oils. This thesis aims to contribute to the ever-growing knowledge of the HDO of lignin-derived model compounds, as the HDO of isoeugenol over Fe- and Fe-Ni-based catalysts was conducted for the first time in this work. The reaction was investigated at 300 °C, and 30 bar total H2 pressure with hexadecane as a solvent. Iron was chosen for the metal modifications of zeolites because it is inexpensive, oxophilic, and environmentally friendly. The synthesized fresh and spent catalysts were characterized using different characterization techniques to explain their activity, selectivity, and stability in the HDO of isoeugenol. The Fe-modified zeolites contained highly dispersed metal nanoparticles and microporous structures, according to the characterization results. However, the unreduced Fe-based catalysts exhibited poor activity in the HDO of isoeugenol as neither cycloalkanes nor alkylbenzenes were formed. A plethora of cracking products was produced, which could have originated both from the reactant and the solvent. The reduced Fe-based catalysts still did not exhibit sufficient HDO activity, as only minor concentrations of deoxygenated products were formed. A suite of novel Fe, Ni, and Fe-Ni supported on H-Y-5.1 support was synthesized to study the synergistic effects of Fe and Ni active sites. Compared to the monometallic Fe and Ni catalysts, the bimetallic Fe-Ni catalyst exhibited better performance in the catalytic HDO of isoeugenol due to the synergy between Fe and Ni sites. The yield of the desired compounds such as propylcyclohexane, ethyl-methylcyclohexane, butylcyclopentane, and propylbenzene over the Fe-Ni catalyst with Fe to Ni weight ratio of 1:1 was 18%, 15%, 7%, and 3%, respectively

Co-processing of fossil feedstock with lignin-derived model compound isoeugenol over Fe-Ni/H-Y-5.1 catalysts

Co-processing of n-hexadecane with lignin derived isoeugenol as a model compound was investigated in this work using low-cost mono- and bimetallic iron and nickel supported on H-Y-5.1 zeolite. Different Fe-Ni metal ratios in the catalyst led to different reaction rates of processes and product distribution. The presence of just 0.26 wt% isoeugenol in the mixture with n-hexadecane made hydroisomerization-hydrocracking of the latter two-fold less active. Catalysts with smaller metal particle sizes, lower than 6 nm were more efficient pointing out on structure sensitivity. Extremely high activity in co-processing was obtained over 2 wt% Fe – 8 wt% Ni/H-Y-5.1 catalysts with the median metal particle size of 4.6 nm and metals-to-acid site ratio of 8.6. Fe catalyst were much less active in isoeugenol hydrodeoxygenation, while high cracking activity of hexadecane was observed in the presence of Ni. Alkylation of n-hexadecane was a feature of 8 wt% Fe – 2 wt% Ni/H-Y-5.1, whereas, over the 5 wt% Fe – 5 wt% Ni/H-Y-5.1 bifunctional catalyst no undesired oxygen-containing cyclic products were detected. This catalyst exhibited the highest hydrogen consumption according to temperature programmed desorption, which can serve as a marker for efficient hydrodeoxygenation. The spent catalysts contained ca 40 wt% of coke with predominantly aliphatic species

Interactions between Iron and Nickel in Fe–Ni Nanoparticles on Y Zeolite for Co-Processing of Fossil Feedstock with Lignin-Derived Isoeugenol

A set of low-cost monometallic Fe, Ni, and bimetallic Fe–Ni bifunctional H–Y-5.1 catalysts with different metal ratios were synthesized by sequential incipient wetness impregnation. The catalysts were characterized in detail by N$_2$ physisorption, Fourier transform infrared spectroscopy with pyridine, inductively coupled plasma optical emission spectroscopy, X-ray diffraction (XRD), transmission and scanning electron microscopy (TEM–SEM), magic angle spinning nuclear magnetic resonance, X-ray photoelectron spectroscopy (XPS), Mössbauer spectroscopy, magnetic measurements, temperature-programmed reduction (TPR), and X-ray absorption spectroscopy (XAS). The results revealed that introduction of Fe led to a decrease of strong acid sites and an increase of medium Brønsted acid sites, while introduction of Ni increased the number of Lewis acid sites. The particle size of iron was approx. 5 nm, being ca. fourfold higher for nickel. XPS demonstrated higher iron content on the catalyst surface compared to nickel. Both Mössbauer spectroscopy and magnetic measurement confirmed the ferromagnetic behavior of all catalysts. In addition, the results from XRD, TEM, XPS, XAS, and magnetization suggested strong Fe–Ni nanoparticle interactions, which were supported by modeling of TPR profiles. Catalytic results of the co-processing of fossil feedstock with lignin-derived isoeugenol clearly showed that both product distribution and activity of Fe–Ni catalysts strongly depend on the metals’ ratio and their interactions. Key properties affected by the Fe–Ni metal ratio, which played a positive role in co-processing, were a smaller medial metal nanoparticle size (<6 nm), a lower metal–acid site ratio, as well as presence in the catalyst of fcc FeNi alloy structure and fcc Ni doped with Fe