Gasification is considered a clean and effective way to convert low quality biomass to higher value gas and solve various waste utilization problems as well. However, only 80% of biomass is converted through thermal processes. The remaining part is char, which requires more time for conversion and in that case reduces the efficiency of gasifier. Seeking to optimize the process of gasification, this work focuses on the intensification of residual char gasification in a gasifier. For this purpose, three different types of char prepared from wood, sewage sludge and tire were examined under different conditions in a lab-scale gasification setup. Results showed that the air flux increase from 0.11 kg/(m²s) to 0.32 kg/(m²s) intensified the gasification process and the gasification rate increased from 0.8 to 2.61 g/min with the decrease of duration of wood char gasification by 72%. An additional introduction of pyrolysis gas into the char gasifier led to decreased bed temperatures, but the gasification rate increased from 0.8 to 1.25 g/min and from 2.61 g/min to 2.83 g/min, respectively, for the wood char and the sewage sludge char. Moreover, the use of pyrolysis gas coupled with air as the gasifying agent enhanced the composition of produced gas from char, and the CO₂ concentration decreased by 1.68 vol% while the H₂ concentration increased by 2.8 vol%.

The global coronavirus (COVID-19) pandemic in early 2020 caused the amount of medical waste, especially plastic waste, to increase. The pandemic exacerbated the plastic waste management problem, including the need to find more sustainable treatment methods. This study investigated the sustainable conversion of plastic waste (FFP2-type face masks) to syngas via pure CO₂ plasma gasification to recover energy and reduce environmental pollution. A direct current (DC) thermal arc plasma torch of 40.6–68.4 kW power generated the plasma stream. Carbon dioxide (CO₂), as a greenhouse gas (GHG), was used as the main plasma-forming gas and gasifying agent. The 140_thermal feedstock input plasma gasification system was used in the study. The effect of the CO₂-to-C ratio on the gasification performance efficiency was investigated. The best CO₂ plasma gasification process performance was obtained at a CO₂-to-C ratio of 2.34. In these conditions, the main syngas components (H₂ + CO) comprised 80.46 vol.% (H₂: 24.62 vol.% and CO: 55.84 vol.%) and the following values were seen for the heating value of the syngas (LHV_syngas: 13.88 MJ/Nm³), the syngas yield (3.13 Nm³/kg_FFP2), the tar content in the syngas (23.0 g/Nm³), the carbon conversion efficiency (CCE: 70.6%), and the cold gas efficiency (CGE: 47.8%). Additionally, the plasma gasification process mass and energy balance were evaluated. It was demonstrated that CO₂ plasma gasification could be a promising thermochemical treatment technology for sustainable plastic waste disposal and the simultaneous utilization of greenhouse gases, such as carbon dioxide.

The eutrophication process, caused by the uncollected seaweed and macroalgae, is a relevant and ongoing ecological issue. In case this biomass is collected from the seashores, it could be used as a potential feedstock for recovery of higher-added-value energy products. This paper aims to investigate the seaweed perspective of uses as a potential feedstock in the slow-pyrolysis process, using microthermal analysis combined with Fourier transform infrared spectrometry and experiments at the laboratory scale at different temperatures with two different types of zeolite catalysts. The primary investigation was performed using a micro-thermal analyser, and the results revealed that seaweed thermally decomposes in two stages, at 250 and 700 °C, while the catalyst slightly decreased the activation energy required for the process, lowering the temperatures of decomposition. Experiments on a laboratory scale showed that the most common compounds in the gaseous phase are C_nH_m, H₂, CO, and CO₂. Nevertheless, the most abundant liquid fraction derivatives are substituted phenolic compounds, pyridine, benzoic acid, naphthalene, d-glucopyranose, and d-allose. Furthermore, the catalyst decreased the amount of higher molecular mass compounds, converting them to toluene (71%), which makes this technology more attractive from the recovery of higher-added-value products point of view.

In current study various aspects of catalyst development for the Sabatier type methanation reaction were investigated. It was demonstrated that starting from 330–380 °C Mg₂NiH₄ hydride heating under CO₂ and H₂ gas flow initiates hydride decomposition, disproportionation and oxidation. These reactions empower catalytic properties of the material and promotes CO₂ methanation reaction. Detailed structural, colorimetric and thermogravimetric analysis revealed that in order to have fast and full-scale development of the catalyst (formation of MgO decorated by nanocrystalline Ni) initial hydride has to be heated above 500 °C. Another considerable finding of the study was confirmation that potentially both high grade and low grade starting Mg₂Ni alloy can be equally suitable for the hydride synthesis and its usage for the promotion of methanation reactions.

In order to implement timely sustainability solutions, road transportation is gradually transitioning to electric power. However, the maritime sector faces challenges in finding ways to shift towards more sustainable fuel. From the perspective of long-distance shipping, electric transport is economically impractical. Therefore, alternative solutions or proposals contributing to the global reduction of pollutant gas emissions in maritime transport are vitally important. This investigation aims to find solutions that enhance the ecological efficiency of intercontinental cargo ships. In this study, an assessment of a magnesium hydride coating was conducted as it is a prospective coating capable of reducing hydrodynamic resistance to save fuel. Due to MgH₂’s ability to release hydrogen at higher temperatures or during a reaction with water, it is expected that this could contribute to an enhancement of the Leidenfrost effect, maintaining a vapor layer on the surface. Samples prepared in situ via reactive magnetron sputtering were submitted to thermal analysis for dehydrogenation range evaluation and the experimental rig for critical (Leidenfrost) temperature identification. In conclusion, thermogravimetric (TG) analysis indicated that the volatile content, primarily hydrogen, in the sample reached approximately 13% by mass. The TG curve exhibited variations in MgH₂ mass, with the most significant mass loss occurring at 300 °C. After conducting critical temperature experiments, the potential of MgO coating was observed to be greater than anticipated when compared to the main material, MgH₂.

This study investigates the combustion of agricultural biomass rich in alkali elements in the fluidized bed. The experiments were performed with smashed corn cob in a 500 kW fluidized bed combustor which was designed for work under low bed temperatures (650–700 °C). During the experiments, the formed compounds from corn cob combustion were measured by sampling particulate matter, and mineral compositions were determined. Also, the temperature profile of the FBC was established. It was determined that the emissions of K and Na elements from the FBC increased from 4 to 7.3% and from 1.69 to 3%, respectively, changing the bed temperature from 650 to 700 °C. Though alkali emissions are reduced at a 650 °C bed temperature, CO emissions are higher by about 50% compared to the case of 700 °C. The addition of 3% of dolomite reduced the pollutant emissions and alkali emissions as well. Potassium content decreased by about 1% and 4%, respectively, at the bed temperatures of 650 °C and 700 °C. The NOx emissions were less than 300 mg/m³ and did not exceed the limit for medium plants regarding DIRECTIVE (EU) 2015/2193. During extended experiments lasting 8 h, no agglomeration of the fluidized bed was observed. Moreover, the proposed configuration of the FBC and its operational parameters prove suitable for facilitating the efficient combustion of agricultural biomass.