Unlocking Syngas Synthesis from the Catalytic Gasification of Lignocellulose Pinewood: Catalytic and Pressure Insights.

Modern technologies transform biomass into commodity chemicals, biofuels, and solid charcoal, making it appear as a renewable resource rather than organic waste. The effectiveness of Mo, Fe, Co, and Ni metal catalysts was investigated during the gasification of lignocellulosic pinewood. The primary goal was to compare the performance of iron and nickel catalysts in the low- and high-pressure production of syngas from pinewood. This is the first study that has reported high-pressure gasification of pinewood without the use of an external gasifying agent, producing syngas containing hydrogen, carbon monoxide, and carbon dioxide along with considerable amounts of methane with or without a catalyst. Also, the same gasification at low pressures was compared. In this study, the iron catalyst produces syngas more efficiently at higher pressure and 800 °C, and contains 43 mol % H2, 22 mol % CO2, 26 mol % CH4, and 8 mol % CO in comparison to the nickel catalyst. High pressure produces a large amount of methane too. The nickel catalyst produces higher syngas at low pressure and 850 °C, and contains 55 mol % H2, 9 mol % CO2, 5 mol % CH4, and 30 mol % CO. Low-pressure gasification produces less amounts of CH4 and CO2. Also, the H2/CO ratio is ∼1.81 using the nickel catalyst at low pressures, which is good for utilizing syngas as a feedstock. These results highlight the importance of catalyst selection, reactor configuration, and operating circumstances in adjusting gasification product composition. The study's findings provide information about optimizing syngas production from pinewood, which is critical for the development of sustainable and efficient energy conversion technologies.

Exploring Synergistic Interactions between Polystyrene and Polyethylene.

An attempt was undertaken to elevate production of aromatic compounds through co-upcycling of polystyrene (PS) and low-density polyethylene (LDPE). The plastics samples were upcycled at 400 °C with catalyst H-ZSM-5. Compared to single plastic upcycling, co-upcycling PS and LDPE demonstrated high advantages: lowered reaction temperature (390 °C), medium reaction rate (-1.35 %/°C), low yield to coke (1.62 % or less) and enhanced aromatics yield (42.9-43.5 %). In-situ FTIR results demonstrated a constant production of aromatics in the 1 : 1 mixed plastic while in pure plastics, aromatic production quickly dropped. Compared to single PS upcycling, co-upcycling PS with PE produced more monocyclic aromatic hydrocarbons (MAHs) at close to 43.0 % versus 32.5 % and less polycyclic aromatic hydrocarbons (PAHs) at 16.8-34.6 % versus 49.5 %. From these data, the synergy between PS and LDPE were confirmed and the mechanism in which they increased MAHs production was proposed.

Insight into Enhanced Microwave Heating for Ammonia Synthesis: Effects of CNT on the Cs-Ru/CeO2 Catalyst.

Ammonia is emerging as a potential decarbonized H2 energy carrier when produced from renewable energy. The on-site production of liquid ammonia from stranded renewable energy can solve the current energy transportation challenges. The employment of microwave technology can produce the desired ammonia product at milder conditions with the supply of intermittent renewable energy sources. Our previous studies have indicated that the Cs-Ru/CeO2 catalyst is a promising catalyst for microwave-driven ammonia synthesis. In this study, the Cs-Ru/CeO2 catalyst mechanically mixed with carbon nanotubes (CNT) and chemically synthesized using coprecipitation and a hydrothermal method is investigated systematically at low temperatures and atmospheric pressure for microwave-assisted ammonia synthesis. Additionally, the combination of two Ru-based catalysts (Cs-Ru/CeO2 and Cs-Ru/CNT) is studied as well. Mechanical mixing of Cs-Ru/CeO2 with CNT exhibited superior activity as compared to the chemically synthesized Cs-Ru/CeO2-CNT catalyst. Besides the enhancement in dielectric property, the probable synergistic effect leads to increased interfacial polarization at the interface of the mechanically mixed catalyst, improving the overall heating and ammonia production rate. Moreover, the combined Ru-based catalyst also exhibited higher activity as compared to their individual activity toward ammonia synthesis. Numerous characterization techniques were performed, including thermal imaging camera and dielectric measurements, to better understand microwave interaction with the composite catalysts.

Thermodegradation of naturally decomposed forest logging residues: Characteristics, kinetics, and thermodynamics.

Combustion and pyrolysis characteristics, kinetics, and thermodynamics of naturally decomposed softwood and hardwood forest logging residues (FLR) were investigated using thermogravimetric analysis. Results showed that calorific values of fresh red pine, two-year decomposed, four-years decomposed, fresh red maple, two-year decomposed, and four-years decomposed were 19.78, 19.40, 20.19, 20.35, 19.27, and 19.62 MJ/kg, respectively. Hemicellulose pyrolysis peak only occurred in the hardwood thermodegradation process. Softwood had a higher pyrolysis yield of solid products (16.08-19.30%) than hardwood (11.19-14.67%). The average pyrolysis activation energy (Ea) of hardwood residue increased with the year after harvest, whereas softwood samples decreased. The average combustion Ea of hardwood samples increased first, then decreased, while that of softwood samples decreased continuously. Enthalpy (ΔH), entropy (ΔS), and Gibbs free energy (ΔG) were also investigated. This research will aid in understanding the thermal decomposition properties of naturally decomposed FLR from various years after harvest.

Investigating co-combustion characteristics of bamboo and wood.

To investigate co-combustion characteristics of bamboo and wood, moso bamboo and masson pine were torrefied and mixed with different blend ratios. The combustion process was examined by thermogravimetric analyzer (TGA). The results showed the combustion process of samples included volatile emission and oxidation combustion as well as char combustion. The main mass loss of biomass blends occurred at volatile emission and oxidation combustion stage, while that of torrefied biomass occurred at char combustion stage. With the increase of bamboo content, characteristic temperatures decreased. Compared with untreated biomass, torrefied biomass had a higher initial and burnout temperature. With the increase of heating rates, combustion process of samples shifted to higher temperatures. Compared with non-isothermal models, activation energy obtained from isothermal model was lower. The result is helpful to promote development of co-combustion of bamboo and masson pine wastes.

Nanofibrillated Cellulose and Copper Nanoparticles Embedded in Polyvinyl Alcohol Films for Antimicrobial Applications.

Our long-term goal is to develop a hybrid cellulose-copper nanoparticle material as a functional nanofiller to be incorporated in thermoplastic resins for efficiently improving their antimicrobial properties. In this study, copper nanoparticles were first synthesized through chemical reduction of cupric ions on TEMPO nanofibrillated cellulose (TNFC) template using borohydride as a copper reducing agent. The resulting hybrid material was embedded into a polyvinyl alcohol (PVA) matrix using a solvent casting method. The morphology of TNFC-copper nanoparticles was analyzed by transmission electron microscopy (TEM); spherical copper nanoparticles with average size of 9.2 ± 2.0 nm were determined. Thermogravimetric analysis and antimicrobial performance of the films were evaluated. Slight variations in thermal properties between the nanocomposite films and PVA resin were observed. Antimicrobial analysis demonstrated that one-week exposure of nonpathogenic Escherichia coli DH5α to the nanocomposite films results in up to 5-log microbial reduction.