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Producing hydrogen (H2) from biomass gasification offers exceptional benefits regarding renewable energy sources, zero‐carbon emission, cost‐effective processes, and high efficiency. The addition of catalysts to biomass gasification could accelerate the process and minimize the formation of coke. However, the catalyst deactivation caused by carbon deposition, poisoning, and sintering is still a significant problem in the gasification process. Therefore, achieving sustainable exploitation of the renewable natural resource of biomass requires substantial development and optimization of the present gasification process. The efficiency of gasification might decrease because of such a process. In this study, CeO2(111) is chosen to investigate the analysis of adsorption molecules during catalytic gasification using the density functional theory method. Three catalyst models, CeO2(111), Zr‐CeO2(111), and Ni‐CeO2(111), have been studied in this work in terms of structural, electronic, and adsorption molecule properties. The structural and electronic properties of the modified catalyst model show the ligand and strain effect on the alloy, with the addition of Zr and Ni as second metals promoting the adsorption capability. Searching for active sites is also carried out by adsorption of selected atoms and molecules and used as a preliminary study to find possible active sites for gasification reactions. The Zr‐CeO2(111) and Ni‐CeO2 catalysts exhibit better adsorption ability on atomics and molecules. The Zr and Ni metals are suitable second metal candidates for the catalyst to proceed with the gasification reaction and simultaneously reduce carbon deposition, poisoning, and sintering problems. [ABSTRACT FROM AUTHOR]

The iron and steelmaking industries play a significant role in the manufacturing sector but result in significant greenhouse gas emissions. Biochar has recently gained attention as a potential substitute for coal in metallurgical processes due to its carbon capture potential. This review explores the potential of biochar as a sustainable substitute for coal in steelmaking industries. Notable research works have shown that substituting biochar in amounts ranging from as low as 5 % to as high as 50 % can be feasible and beneficial in processes such as coke making, iron sintering, blast furnaces, and electric furnaces. The information presented in this review can be applied to create sustainable and competitive alternatives to fossil fuels to help decarbonize metallurgical industries. [ABSTRACT FROM AUTHOR]

The effect of potassium impregnation at different concentrations during gasification, under nitrogen/water steam atmosphere, of char produced via pyrolysis of olive mill residues blended or not with pine sawdust was investigated. Three concentrations (0.1 M, 0.5 M, and 1.5 M) of potassium carbonate solution (K2CO3) were selected to impregnate samples. First, four types of pellets were prepared; one using exhausted olive mill solid waste (G) noted (100G) and three using G blended with pine sawdust (S) in different percentages (50%S–50%G (50S50G); 60%S–40%G (60S40G); 80%S–20%G (80S20G)). Investigations showed that when isothermal temperature increases during the gasification conducted with two water steam percentages of 10% and 30%, the reactivity increases with potassium concentration up to 0.5 M, especially for 100G. Still, higher catalyst concentration (1.5 M) showed adverse effects attributable to silicon release and char pore fouling. Moreover, the effect of the steam concentration on the gasification reactivity was significant with the non-impregnated sample 100G. Finally, a kinetic study was carried out to determine the different kinetic parameters corresponding to the Arrhenius law. [ABSTRACT FROM AUTHOR]

The burgeoning environmental crisis and the urgent need for sustainable energy solutions underscore the importance of innovative waste-to-energy conversion technologies. This study aims to an efficient utilize of face mask waste for a novel energy system to address waste management and energy production simultaneously by introducing an integrated system comprising a gasifier reactor, steam methane reformer, and water-gas shift reactor, designed to convert face mask waste into a hydrogen-rich syngas. The gasifier reactor initiates the process with a hydrogen flow rate of 2.352 mol/h, which is subsequently enriched to 5.405 mol/h in the steam methane reformer and further to 6.132 mol/h in the water-gas shift reactor, marking a cumulative increase of 160%. Methane content, initially at 2.017 mol/h, is reduced by 38.4% post-reforming and remains stable through the water-gas shift reaction. Carbon monoxide sees a significant reduction from 0.8558 mol/h to 0.1817 mol/h, a decrease of 78.8%. The findings of this study have profound implications for the energy sector, demonstrating the potential of the integrated system to not only mitigate waste but also to produce clean energy efficiently. The substantial increase in hydrogen content across the reactors highlights the system's capability to support the burgeoning hydrogen economy, while the management of carbon oxides aligns with environmental sustainability goals. The value of this study lies in its contribution to the advancement of waste-to-energy technologies and its role in shaping future energy policies and practices. • An innovative waste-to-energy conversion technology is developed. • Face mask waste gasification is integrated with SMR and WGSR. • Hydrogen flow rate in the gasifier is 2.352 mol/h. • Hydrogen flow rate is increased to 5.405 mol/h in SMR and 6.132 mol/h in WGSR. • This integration improves the hydrogen flow rate by 160%. [ABSTRACT FROM AUTHOR]

With increasing efforts to lower CO2 emissions globally, the demand for carbon-based resources in industries remains on a high level, leading to new technologies being able to provide those essential carbon sources. To the best of our knowledge, we were able to show for the first time the adaption of a readily available gasifier for the gasification of wood chips using only O2 (18.4–23.1 Vol.-%) and CO2 as gasification agents, creating a nitrogen-free product gas. It was found that the setup used was able to convert up to 27.2% of the CO2 from the gasification agent to CO, creating a promising route for the production of renewable carbon sources for future carbon-based applications. Furthermore, no decrease in gasification performance was observed as the cold gas efficiency was at 83.5–95.5% with only minor formation of tar. [ABSTRACT FROM AUTHOR]

A conceptual design of coffee stem biomass gasification was developed using the Aspen Plus process simulator, which was analyzed based on energy criteria such as the lower heating value of the produced synthesis gas and cold gas efficiency. The results yielded a lower heating value of 5.07 kJ/MJ, with a cold gas efficiency of 77.45% and a yield of 2.75 kg gas/kg biomass, all operating under optimal conditions with studied parameters including an air-to-biomass ratio between 1.8 and 2.5, gasifying agent temperature of 260 °C, and biomass moisture content below 10%. A sensitivity analysis was conducted on the formation of the most important compounds for synthesis gas quality (H2, CO, CO2, H2O, CH4). This involved understanding the reactions occurring throughout the gasification reactor and evaluating process parameters such as feed moisture content, gasification section temperature, and the ratio between feed and gasifying agent flows to optimize the process with the aim of improving product quality and reducing residue formation. The simulation scheme was validated against experimental data, yielding results consistent with reality. This contributed valuable information towards process optimization for projects targeting the Colombian coffee sector, paving the way for future gasifier designs tailored to the quantity of raw material to be processed. [ABSTRACT FROM AUTHOR]

The gasification removal behaviour of phosphorus from high‐phosphorus iron ore is theoretically and experimentally studied in the temperature range of 400–900 °C under H2 reducing and N2 atmospheres. In the first step, thermodynamic analysis is conducted to reveal the gasification and reaction behaviours of common phosphorus compounds, namely P4O10, FePO4, AlPO4, Ca2P2O7, and Ca3(PO4)2. The results indicate that P4O10, FePO4, and AlPO4 under H2 reducing atmosphere and P4O10 under a N2 atmosphere can be removed by gasification, and the influence of the interaction between the vaporized gases and iron ore should be investigated. Therefore, dephosphorization experiments are performed on simulated iron ores containing P4O10, FePO4, or AlPO4. For the sample containing P4O10, ferric phosphates and iron phosphides are formed under the N2 and H2 reducing atmospheres, respectively, and their formation rates decreases with decreasing temperature, becoming almost stagnant at 400 °C. Moreover, it is confirmed that FePO4 and AlPO4 cannot be removed even when pure H2 is introduced. [ABSTRACT FROM AUTHOR]

The use of fossil fuels has been essential to the development of society, but has also contributed partly to global warming. For example, carbon dioxide emissions from fossil fuels and industries have increased by 60% since 1990, calling for the recycling of modern biomass in the context of a carbon neutral economy. Here we review the hydrothermal conversion of biomass into biofuels, chemicals and biomaterials with emphasis on subcritical water properties, hydrolysis of biomass, steam explosion, fractionation, carbonization, liquefaction, gasification, and fractionation of bio-oil. We observe that hydrothermal conversion of biomass in the presence of water at subcritical conditions produces value-added compounds with high process efficiency. Subcritical water allows rapid reaction rates, low mass transfer resistance, and gas-like diffusivity. [ABSTRACT FROM AUTHOR]

A detailed process model is proposed to simulate the air-gasification of biomass (wood chips) in a bubbling fluidized bed gasification system at different temperatures (650–800 °C) and equivalence ratios, ERs (0.08–16), using ASPEN Plus simulator. The process was assumed fully steady-state, and gasification section was modeled by implementing FORTRAN user-subroutines for reaction kinetics and hydrodynamic parameters. Experimental results from air-gasification of wood chips in a bubbling fluidized bed gasifier were used to validate the model. The model predictions were in good agreement with experimental results. The validation results also showed that ASPEN Plus can describe the gasification process in fluidized bed gasifiers well. Specifically, ER initially decreased the carbon conversion efficiency (CCE), with a minimum followed by an increase. An optimal ER was crucial for minimizing tar yield (TY). Higher temperatures yielded higher H2 contents and lower tar yields. Smaller particles decreased TY and increased gas lower heating value (LHV). Under optimal conditions (ER = 0.13, T = 750 °C, and D = 0.2 mm), the product gas generated during air-gasification of wood chips achieved a low tar yield of 4.61 g/Nm3. These results confirmed the significant potential of biomass gasification in high-quality syngas production with low tar content. This article also provides valuable information for selecting operation conditions to achieve high-quality syngas for engineering applications and lays a foundation for the design of industrial-scale fluidized bed gasifiers in the future. [ABSTRACT FROM AUTHOR]

The catalytic activity of Ni/dolomite during biomass (wood chips) gasification was examined in a fluidized bed reactor. Ni-dolomite with Ni contents of 0% (dolomite), 10%, 20% and 25% (25%Ni/dolomite) was prepared by precipitating method. Effect of equivalence ratio, ER (0.078–0.128), temperature (700–850 °C) and Ni content on syngas composition, gas yield (GY), tar content in the product gas (TC), char conversion efficiency (CCE) and cold gas efficiency (CGE) was studied. An increase in ER led to an increase in GY and CCE, while TC gradually decreased. Increasing temperature contributed to more char conversion, gas production and tar elimination. The results also showed that Ni/dolomite had a high catalytic activity in terms of tar cracking/reforming, upgrading the produced syngas quality, as well as enhancing char conversion. Higher Ni content (0–20%) was more favorable for gas production, char conversion and tar reduction. However, a further increase in Ni content led to a slight increase in the gas quality and yield due to coke formation and subsequently a reduction in the availability of CaO and MgO active sites. Comparing with dolomite, the use of Ni/dolomite improved the gas quality and the gasifier performance, the optimal value of Ni content was found to be 20% at 850 °C and ER of 0.128. [ABSTRACT FROM AUTHOR]

Spent coffee grounds (SCGs), a waste product of the coffee industry, present a significant untapped resource for fuel production. This study aims to optimize the gasification of SCG using various metal catalysts (NiO, MnO2, Al2O3, and Fe2O3) to maximize syngas yield. SCG samples were gasified at different temperatures (800 °C, 900 °C, 1000 °C) and analyzed using Scanning Electron Microscopy (SEM), Thermogravimetric Analysis (TG-DTA), and Fourier Transform Infrared (FTIR) spectroscopy to evaluate catalyst performance and reaction mechanisms. The findings indicated that utilizing mixing techniques for physical contact to introduce catalysts led to a uniform distribution of catalyst particles throughout the sample. The decomposition rate of the gasification experiment after adding the catalyst was 24% faster than that of the pure SCGs. In the gasification experiment, the MnO2 catalyst showed the highest CO production, which was 71% higher than that of NiO under the same conditions. At this temperature, MnO2 generated around 171% more CO than at 800 °C, surpassing the yields observed with other catalysts. The study concludes that Mn emerged as the most promising catalyst, significantly improving both CO and CH4 yields. Selecting the appropriate metal catalyst and optimizing operational temperatures are crucial for enhancing the efficiency of SCG gasification. [ABSTRACT FROM AUTHOR]

The sustainable utilization of biomass, particularly troublesome waste biomass, has become one of the pathways to meet the urgent demand for providing energy safety and environmental protection. The variety of biomass hinders the design of energy devices and systems, which must be highly efficient and reliable. Along with the technological developments in this field, broad works have been carried out on the mathematical modeling of the processes to support design and optimization for decreasing the environmental impact of energy systems. This paper aims to provide an extensive review of the various approaches proposed in the field of the mathematical modeling of the thermochemical conversion of biomass. The general focus is on pyrolysis and gasification, which are considered among the most beneficial methods for waste biomass utilization. The thermal and flow issues accompanying fuel conversion, with the basic governing equations and closing relationships, are presented with regard to the micro- (single particle) and macro-scale (multi-particle) problems, including different approaches (Eulerian, Lagrangian, and mixed). The data-driven techniques utilizing artificial neural networks and machine learning, gaining increasing interest as complementary to the traditional models, are also presented. The impact of the complexity of the physicochemical processes and the upscaling problem on the variations in the modeling approaches are discussed. The advantages and limitations of the proposed models are indicated. Potential options for further development in this area are outlined. The study shows that efforts towards obtaining reliable predictions of process characteristics while preserving reasonable computational efficiency result in a variety of modeling methods. These contribute to advancing environmentally conscious energy solutions in line with the global sustainability goals. [ABSTRACT FROM AUTHOR]

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The increasing waste generation trends resulted in growing attention to the technologies that aim to reduce or prevent landfilling. The pyrolysis and gasification of refuse-derived fuel (RDF) allow waste to be turned into new raw materials, like pyrolysis gas and syngas. However, the wet gas cleaning processes result in the production of highly contaminated liquid waste. Phenolic compounds are common constituents of this wastewater and often appear in the wastewater of other industries as well. In this research, the laboratory-scale steam gasification of an RDF char was performed to produce syngas and adsorbent simultaneously. The RDF was previously pyrolyzed at 700 °C maximum temperature in a Hungarian pyrolysis pilot plant with approximately 120 kg h−1 capacity. In this thermal waste processing plant, the pyrolysis gas is already utilised by burning, but currently, the char ends up in landfills. The gasification of char samples was examined with different steam-to-carbon ratios (0.56, 0.84, and 1.12) and duration (30, 60, and 120 min) at 900 °C. Following gasification, the phenol removal capability of the solid by-products was investigated. The results show that its composition and energetic properties make the produced syngas more suitable to use as a raw material in the chemical industry rather than a fuel. At lower concentrations, the effectiveness of the solid by-product for phenol removal was comparable to commercial activated carbon. These are promising results about producing activated carbon from waste without any chemical treatment. [ABSTRACT FROM AUTHOR]

Fossil fuels are deemed to diminish because of their limited availability, no renewability, and emissions of greenhouse gases and other poisonous materials to the atmosphere and the ecosystem. Renewable energy based on sustainable biomass has occupied an increasing share of the energy system over the past decade. Among several massively cultivated crops worldwide, corn, sugarcane bagasse, and soybean straws are some of the leading agricultural by-products that can generate substantial energy (e.g., biofuels, hydrogen) as vital sustainable energy to substitute non-renewable fossil fuels. This paper aims to review recent progress in renewable energy generation from biomass based on thermochemical techniques-i.e., gasification, pyrolysis, and liquefaction-detailed technical features and their application for extraction energy from biomass. The quality, composition, and productivity of renewable energy extracted from biomass based on existing thermochemical techniques are compared, and their technical dependencies upon the thermochemical processes are discussed. Furthermore, analysis of technical deficiencies of existing methods, and exploration of innovative emerging technologies for high-efficiency and high-quality renewable energy generation from biomass straws. In general, biomass gasification stands out as the most efficient technique for hydrogen production (HP) from biomass due to mature technology, high hydrogen yield, and potential for integration with other presented techniques. [Display omitted] • A detailed review of HP from biomass using thermochemical techniques. • Discussion about gasification, pyrolysis, and liquefication working principles. • Comparison between all types of presented thermal techniques. • Advantages and disadvantages of gasification, pyrolysis, and liquefication. • Overall performance of all thermal techniques presented in this review. [ABSTRACT FROM AUTHOR]

This review examines the potential of municipal solid waste (MSW) as a renewable energy source, focusing on recent advances in thermochemical conversion technologies and their environmental impacts. The exponential growth of urban populations has led to a surge in MSW, necessitating sustainable waste management solutions. Traditional disposal methods, such as landfilling and incineration, have significant environmental drawbacks. However, advancements in waste-to-energy (WtE) technologies, including incineration, pyrolysis, and gasification, offer promising alternatives for energy recovery and resource utilization. This review explores the composition of MSW, its classification as a renewable resource, and the thermochemical conversion technologies that transform waste into energy. The environmental impacts of these technologies, particularly emissions and air quality concerns, are critically analyzed. The review highlights the evolving regulatory landscape and the implementation of advanced emission reduction systems. The findings underscore the importance of integrating innovative waste management strategies to promote a circular economy and achieve sustainable development goals. [ABSTRACT FROM AUTHOR]

The gasification of sewage sludge (SS) and digestate was investigated in a pilot-scale fluidized bed gasifier with an output of 100 kWt. The treatment of these by-products is an ongoing challenge for sustainable development. SS and digestate are most commonly used as fertilizers. However, regulations restrict their use, mainly because of the content of heavy metals, pathogens and bacteria. Gasification of these by-products instead of application to agricultural land seems to be more efficient, as the syngas can subsequently be used for combined heat and power (CHP) generation. A series of measurements were carried out to get a better understanding of the gasification process of these fuels and to study the effects of gasifying agent on the syngas composition, particulate matter (PM) and tar. The produced syngas and tar were analyzed using a gas chromatograph with mass spectrometry (GC–MS). The results showed that no ash slagging was observed and therefore it is feasible to operate digestate and SS gasification at 750°C. The lower heating value (LHV) of the syngas from digestate and SS with air as the gasifying agent is comparable, 4.06 MJ·Nm−3 for digestate and 4.11 MJ·Nm−3 for SS. The addition of steam had a positive effect on the amount of tar and the tar dew point, which was below 150°C. Tar reduction in digestate was 5037.3 mg·Nm−3 to 3566.3 mg·Nm−3 and in SS 7447.7 mg·Nm−3 to 3390.3 mg·Nm−3. Furthermore, the concentrations of the individual tar compounds were determined and subsequently divided into tar classes. [ABSTRACT FROM AUTHOR]

With the increasingly serious problems of energy shortage and environmental degradation, countries around the world are actively developing safe, environmentally friendly, and renewable energy. Biomass energy has become an ideal substitute for fossil fuels due to its abundant reserves, good renewable performance, and zero carbon emissions. This paper discusses the importance and potential of biomass energy as a renewable energy source for China's energy development, mainly including the three biomass conversion methods of physics, chemistry, and biology, seven utilization technologies, such as direct combustion, gasification, and pyrolysis, and five application approaches, such as biomass power generation, biomass gas fuel, biomass liquid fuel, and bio-based materials. This review systematically analyzes the challenges faced by China's development of biomass energy and discusses the future development direction of biomass. The utilization of biomass resources should take a comprehensive and high-value path. China is actively looking for new energy utilization paths, and biomass energy has become a key measure to cope with carbon emission reduction, climate change, and ecological environment protection. [ABSTRACT FROM AUTHOR]

The increasing amount of sewage sludge produced demands new methods of its management to minimize socioeconomic and environmental problems related to its current treatment. An effective solution may be the thermochemical conversion of sewage sludge through gasification. First, the most known sewage sludge gasification processes are presented along with the challenges that they face. Then the detailed characteristics of sewage sludge are discussed from the point of view of its use in the gasification process, as well as research on the kinetics of gasification of sewage sludge char using various models. As scientific reports on sewage sludge gasification focus on the influence of process parameters on gas yield and composition (especially H2 and tar content), the main part of the work is devoted to the discussion on the influence of temperature, type, and amount of the gasifying agent and the presence of a catalyst on these parameters. Moreover, the co-gasification of sewage sludge as well as advanced gasification methods, i.e., supercritical water gasification and plasma gasification, are analyzed. Finally, the possibilities of utilization of sewage sludge gasification process by-products were discussed and the impact of the process on the environment was assessed. The review concludes with indications of directions for further research. [ABSTRACT FROM AUTHOR]

To increase the carbon conversion of char in gasification, this paper aimed to reveal the gasification behaviours of char residues. Char residues with different ash contents in this work were prepared from Shenmu char and Tejing char. Those char residues were gasified by different CO2 gas mixtures at different temperatures. The gasification process of char residue was different from the end stage of the gasification process of the corresponding raw char: the gasification rate of the char residue increased at first and then decreased, whereas the gasification rate of the corresponding raw char kept decreasing during the end stage of gasification. The highest gasification rate was achieved at a lower conversion in the gasification of char residue than in the gasification of the corresponding raw char. Catalytic minerals, high temperature, and high CO2 partial pressure benefited the gasification of gasified char residues. The char residues that contained more catalytic minerals were more reactive in gasification and were less sensitive to changes in temperature and CO2 partial pressure. The Modified Random Pore Model (MRPM) and Random Pore Model (RPM) were used to predict the gasification kinetics of the chars, and the MRPM describes the gasification processes of gasified char residues well. [ABSTRACT FROM AUTHOR]

Biochar, a solid material derived from a thermochemical process, has received significant attention due to its usefulness in various sectors. Previous studies have been conducted to improve the properties and quality of this material by altering the thermochemical processes, treating the feedstock, hybridizing the feedstock, and so forth, but little has been done on the effect of varying the reactor's configuration. This research aims to study the effect of varying the stainless‐steel‐based combustion compartment volume of a biomass‐fueled top‐lit updraft gasifier on the groundnut shell biochar. The biochar yields for reactors ranged from 34.9% to 51.2%. The sample produced in the smallest combustion compartment volume showed the highest carbon content, according to energy dispersive X‐ray spectroscopy (EDX) analysis. Potassium, another major element, decreased as the combustion compartment was reduced. Scanning electron microscopy (SEM) analysis revealed that the biochar samples produced had an irregular shape and rough surfaces, and reducing the combustion compartment volume resulted in larger particles on the surface. Fourier transform infrared (FTIR) spectroscopy analysis showed similarities and differences in peaks observed for all the samples. The biochar samples produced can find applications in wastewater treatment, energy conversion and storage, and soil amendment, and the findings contribute to the design and optimization of biomass‐based gasifiers. [ABSTRACT FROM AUTHOR]

In the process of poplar fermentation for ethanol, different methods are adopted to achieve efficient treatment and resource utilization of fermentation residues, which meets the current demand for green energy and carbon neutrality. Therefore, this work aims to establish an evaluation method on energy consumption, pollutant emissions, and cost expenditures in the production process for biofuels from poplar wood and residue. The process was simulated with commercial software (Aspen Plus for chemical production simulation and cost estimation and eBalance for LCA). Results showed that compared to FCE, it made a higher conversion efficiency of CFG because of the biojet fuel and gasoline from the gasification and conversion of residual lignin. And the flash evaporator, hydrolysis reactor, and fermentation reactor were components with the highest exergy loss. The economic cost of CFG was 9.63% less than that of FCE, and cellulase enzymes and poplar wood in variable costs were main factors in the total cost. Comparing environmental impacts from four perspectives, it was found that the total comprehensive impact of FCE was higher than that of CFG under each weight. The degree of influence of the first level indicator layer was energy consumption, environmental impact, and economic cost in descending order. [ABSTRACT FROM AUTHOR]

The production of heterogeneous solid waste, such as municipal solid waste (MSW), construction and demolition waste (CDW), and industrial solid waste (ISW), has increased dramatically in recent decades, and its management is one of today's biggest concerns. Using waste as a resource to produce value-added materials such as char is one of the most promising strategies for successful and sustainable waste management. Virtually any type of waste, through various thermochemical technologies, including torrefaction, pyrolysis, hydrothermal carbonization, and gasification, can produce char with potential material and energy applications. Pyrolysis is the most widespread technology, and there are more studies on producing and applying waste-derived char using this technology. The properties of waste-derived char seem to be influenced by the conversion technology and conditions, as well as by the composition of the source waste. A literature search indicated that the properties of waste-derived char are highly variable with the composition of the raw material, with carbon content in the range 8–77%, a higher heating value of 2.5–28.4 MJ/kg and a specific surface area of 0.7–12 m2/g. Depending on the properties of char derived from waste, there are greater or minor difficulties in applying it, with ash content, heavy metals, and polycyclic aromatic hydrocarbon (PAH) concentrations being some of its limiting properties. Therefore, this review attempts to compile relevant knowledge on the production of waste-derived char, focusing on heterogeneous solid waste, applied technologies, and practical application routes in the real world to create a supply chain, marketing, and use of waste-derived char. Some challenges and prospects for waste-derived char are also highlighted in this study. [ABSTRACT FROM AUTHOR]

Energy sources all around the world are degrading at a rapid pace. The exponential rise in population, along with urbanization, requires exploration and advancement in diverse fuel resources. Municipal solid waste (MSW) disposal requires urgent intervention in terms of its utilization and conversion into useful energy forms than being dumped into landfills. Though efforts are being made for its combustion in furnaces, the plastic contents in RDF often pose environmental concerns when used for combustion. The gasification process has been explored for the effective processing of different forms of waste in the present study. The composition of MSW varies widely with demography, weather, and habitats. In the present study, MSW of Surat metropolitan city of India is processed post collection, through sorting, segregation, and compaction, and transformed to fuel, which is termed as refuse-derived fuel (RDF). A chemical representation of the RDF is used to perform gasification studies with the help of two thermodynamic equilibrium models. Parametric analysis of the gasification models is performed to analyze the effect of equivalence ratio and gasification reaction temperatures on the product gas composition for the prepared composition of RDF. Results reveal that the combined equilibrium model is more accurate in predicting product gas composition compared to the Homogeneous model. It is observed that the variation of the equivalence ratio has a more significant influence on the product gas composition than the variation in the gasification temperature. The study concludes that RDF from MSW may be efficiently transformed into useful gaseous fuel through gasification resulting in product gas with a calorific value of approximately 25 MJ per kg of RDF gasified. [ABSTRACT FROM AUTHOR]

Energy is a crucial factor for urban development. Cities have a crucial role in climate change, as they use 2/3 of the world's energy, producing 70% of greenhouse gas (GHG) emissions. In order to reduce the large ecological footprint of the utilization of conversional energy sources (coal, gas, and oil) and enhance a nation's energy independence (security), it is crucial to find alternative fuels. Biomass residues are characterized as a sustainable and carbon-neutral energy source. Hence, this review describes a critical assessment of not only the quality characteristics of several waste and biomass residues for bioenergy production and biofuels but also the value-added products that could be produced from wastes to enhance industry (e.g., pharmaceutical, cosmetics, packaging industry, etc.). Furthermore, the challenges and potential solutions of waste utilization for bioenergy production and the transformation of value-added products for urban sustainability are also explored. Despite the high-quality characteristics and the availability of these wastes, several critical factors should be taken into account. Biomass residues could contribute to sustainable development goals (SDG), such as sustainable cities and communities, clean energy, responsible consumption and production, the economic growth of a country, and, as a result, urban development. [ABSTRACT FROM AUTHOR]

Since 1950, only 9% of all plastic produced has undergone recycling, and a mere 10% of that has been recycled multiple times. Most discarded plastic (around 73%) ends up in landfills or is improperly managed, resulting in widespread littering. The main reason for low recycling rates is the lack of recycling technology for multi‐polymer and multi‐layer materials and unsortable mixed plastic waste. This plastic waste is one of the most accumulating types, including for example single‐use food packaging with an average lifetime of less than 6 months. These multi‐layer films, consisting of various polymer types, are not feasible for traditional mechanical recycling, which requires well‐sorted, clean, and homogeneous materials. Several methods for plastic recycling have been proposed to address this issue and tackle the overwhelming influx of plastic waste, among which steam gasification stands out as one of the most promising approaches for recycling mixed, contaminated, and unsortable plastics. This method utilizes high temperatures (≥800°C) to atomize the plastics, resulting in a gas mixture of H2, CO, and CO2 and small hydrocarbons. The resulting gas can be reformed through hydrocarbon syntheses, for example, via methanol to propylene and ethylene, and successive into new mono‐ and polymers of equal quality to fossil‐based plastics. Moreover, since the high temperatures atomize any organic structure, biomass can be used as a substitute for an extension of the carbon feed, ultimately reducing reliance on fossil feedstock. With these advantages, steam gasification can significantly increase recycling rates and contribute to a bio‐integrated circular carbon economy. [ABSTRACT FROM AUTHOR]

The average annual global production of waste textiles exceeds 92 million tons, with the majority landfilled and incinerated, resulting in energy waste and environmental pollution. In this study, a thermal conversion process for waste textiles by gasification coupling with catalytic reforming under a steam atmosphere was proposed. The gasification performance of the waste textiles jumped with the introduction of steam and catalyst compared to pyrolysis at 800 °C. The syngas yield increased from 20.86 to 80.97 mmol/g and the hydrogen concentration increased from 17.79 to 50.91 vol.%, which was an increase of 288.12% and 186.18%, respectively. The excellent gasification performance mainly came from two sources: steam promotion for volatiles production and Fe-N-BC promotion for steam reforming of volatiles by Fe2O3, Fe3O4, Fe-Nx, etc. This study has achieved the efficient production of hydrogen-rich syngas from waste textiles, providing a new idea and theoretical basis for the effective removal and utilization of waste textiles. [ABSTRACT FROM AUTHOR]

Last few decades observed decrease in the quality of the extracted crude oil. Moreover, heavy crudes are cumbersome to refine with conventional processes due to the production of high sulfur residues and low light distillates. Their combustion also generates significant pollutants including particulates, sulfur and nitrous oxides. Gasification is a potential pathway for the declining quality of the crude oil and avoiding environmentally harmful residuals. Here, the technical viability of gasifying different crude oil was investigated with numerical and equilibrium analysis, and the output performance was compared to the gasification of baseline coal. The equilibrium model is based on elemental mass and energy conservations. The assessment of the influence of different parameters such as equivalence ratio, crude oil type and operating temperature on the efficiency of the gasification process was conducted. Results reveal a high gasification efficiency ~ 77% which surpasses the coal efficiency (~ 73%). Furthermore, similar sensitivity trend was observed for both fuels with varying moderator and oxidizer conditions. Devolatilization kinetics of crude oil was determined to run high-fidelity gasification. The third order Coats-Redfern provided the best fit method with dual kinetics for the activation energies and frequency factors of 463.648 kJ/mole and 1.455E+56 s−1, 276.408 kJ/mole and 3.325E+20 s−1 and 96.281 kJ/mole and 5.186E+03 s−1 for the light-, semi- and heavy crudes, respectively. Furthermore, gasification economics assessment of crude oils was conducted given their technical viability and environmental advantages. Using the current crude oil price of about $80/barrel ($0.588/kg) and considering the local sensible energy price in UAE (i.e., 38 fils/kWh) (~ $0.10354/kWh), the process shows potential economic viability between 1150 °C and 1300 °C. [ABSTRACT FROM AUTHOR]

Indonesia is a country that has abundant natural resources such as palm oil, coal and so on. These two types of coal mining and palm oil plantation sectors have provided many benefits for community welfare. The aims of research is to utilize palm oil industry waste in the form of empty fruit bunch (EFB) and fine coal waste (FCW) into synthetic gas (syngas) through a catalytic gasification process which is then used as a source of energy and/or synthesis chemicals. Gasification temperatures are 450 oC, 550 oC and 650 oC. Gasification time 20, 30 and 40 minutes. The ratio between pillared bentonite catalyst and EFB is 0.125 and 0.25. The resulting syngas is analyzed for the content of H2, CO, CH4 and CO gases. At gasification temperatures of 650 oC, the H2/CO gas ratio is 2.27. The comparison value between combustible gas (H2, CO and CH4) and non-combustible gas (CO2), namely the CG/NCG ratio shows the quality of a syngas. The higher the CG/NCG value, the better syngas is as a gas fuel because it has a higher heating value. The CG/NCG value at a temperature 650 oC it is 21.41. With an increase in temperature from 450 oC to 650 oC the increase in CG/NCG value is 51%. Thus, increasing the temperature from 450 oC to 650 oC, there is an increase in HHV of 86.21%. This result is economically beneficial because the increase in calorific value will increase the benefits of syngas. The higher the HHV value, the better the syngas is used as gas fuel. The HHV value at a temperature of 650 oC is 13.91 MJ/Nm3. Thus, by increasing the gasification temperature from 450 oC to 650 oC, there is also an increase in LHV of 85.71%, meaning it has increased quite significantly. When compared with the use of 0.125% catalyst, the increase in catalyst concentration of 0.25% is smaller than 91.90%. From the experimental results it can be concluded that increasing temperature will improve the quality of syngas.

The production of heterogeneous solid waste, such as municipal solid waste (MSW), construction and demolition waste (CDW), and industrial solid waste (ISW), has increased dramatically in recent decades, and its management is one of today’s biggest concerns. Using waste as a resource to produce value-added materials such as char is one of the most promising strategies for successful and sustainable waste management. Virtually any type of waste, through various thermochemical technologies, including torrefaction, pyrolysis, hydrothermal carbonization, and gasification, can produce char with potential material and energy applications. Pyrolysis is the most widespread technology, and there are more studies on producing and applying waste-derived char using this technology. The properties of waste-derived char seem to be influenced by the conversion technology and conditions, as well as by the composition of the source waste. A literature search indicated that the properties of waste-derived char are highly variable with the composition of the raw material, with carbon content in the range 8–77%, a higher heating value of 2.5–28.4 MJ/kg and a specific surface area of 0.7–12 m2/g. Depending on the properties of char derived from waste, there are greater or minor difficulties in applying it, with ash content, heavy metals, and polycyclic aromatic hydrocarbon (PAH) concentrations being some of its limiting properties. Therefore, this review attempts to compile relevant knowledge on the production of waste-derived char, focusing on heterogeneous solid waste, applied technologies, and practical application routes in the real world to create a supply chain, marketing, and use of waste-derived char. Some challenges and prospects for waste-derived char are also highlighted in this study.

Process design critically depends on the characterization of fuels and their kinetics under process conditions. This study steps beyond the fundamental methods of thermogravimetry to modulated (MTGA) and Hi-Res™ (high resolution) techniques to (1) add characterization detail and (2) increase the utility of thermal analysis data. Modulated TGA methods overlay sinusoidal functions on the heating rates to determine activation energy as a function of temperature with time. Under devolatilization conditions, Hi-Res™ TGA maintains a constant mass loss with time and temperature. These two methods, run independently or overlaid, offer additional analysis in which multiple samples at different heating rates are run to different final temperatures. Advanced methods allow researchers to use fewer samples by conducting fewer runs, targeting practical experimental designs, and quantifying errors easier. The parameters of the studies included here vary the heating rate at 10, 30, and 50 °C/min; vary gas-phase oxygen for pyrolysis or combustion conditions; and particle size ranges of 100–125 µm, 400–425 µm, and 600–630 µm. The two biomass fuels used in the studies are pinewood from Northern Sweden and wheat straw. The influence of torrefaction is also included at temperatures of 220, 250, and 280 °C. Apparent activation energy results align with the previous MTGA data in that combustion conditions yield higher values than pyrolysis conditions—200–250 kJ/mol and 175–225 kJ/mol for pine and wheat combustion, respectively, depending on pre-treatment. Results show the dependence of these parameters upon one another from a traditional thermal analysis approach, e.g., the Ozawa-Flynn-Wall method, as well as MTGA and Hi-Res™ thermogravimetric investigations to show future directions for thermal analysis techniques.

This proposed research investigates the sustainable and innovative use of biomass gasification for generating electricity. Biomass gasification is a versatile and eco-friendly technology that converts organic materials, such as agricultural residues, forestry waste, and even municipal solid waste, into a valuable source of clean energy. This research delves into the various aspects of this technology, including its processes, efficiency, environmental impact, and potential applications in power generation. Biomass gasification gas, often referred to as syngas, presents a promising avenue for addressing the rising energy demand while lowering greenhouse gas emissions and preventing climate change. This research seeks to offer a thorough insight into the principles and practices behind biomass gasification, highlighting its role in the transition towards a sustainable and renewable energy future. The research will investigate the technical and economic feasibility of utilizing biomass gasification gas for electricity generation, examining the benefits, challenges, and opportunities associated with this alternative energy source. By addressing critical issues such as feedstock availability, gasifier technology, gas cleaning processes, and power plant integration, this study seeks to offer valuable insights into the potential of biomass gasification gas as a clean and renewable energy solution.

The fundamental significance of using cattle manure as a case study is the risk of continuing pollution, caused by its poor management in connection to the increasing demand for animal-derived food. Pyrolysis and gasification, effective solutions with real valorization potential, are the proposed techniques of converting this type of waste into valuable products. After a complete initial characterization, cattle manure is converted into hydrogen-rich syngas, using a modular hybrid fixed-bed reactor, at a generous thermal range, 700 °C to 875 °C, under different process agents, without the use of steam or the addition of catalysts. In comparison to gasification, the quantification of syngas demonstrates higher yields in pyrolysis processes, but with a lower energy potential. The content of the syngas in hydrogen, ⁓ 25 vol% and hydrocarbons, ⁓ 25 vol%, emphasized by an energetic value of ⁓ 17 MJ/m3, holistically places the gasification process in a slight advantage in relation to pyrolysis, exceeding the values presented by other studies on similar matrices and technical conditions. The forecast investigation of syngas composition through polynomial functions shows a significant drop in hydrogen and hydrocarbon concentrations after the 80-min sampling period. [Display omitted] • Pyrolysis and gasification are potential options for cattle manure management. • The experiments were developed into an updraft fixed bed modular hybrid reactor. • The process gas is critical in determining the composition development of syngas. • Temperature variation alone did not disclose distinct trends. • Superior performance in average H 2 production is ascribed to gasification with 21 vol% CO 2. [ABSTRACT FROM AUTHOR]

The gasification of olive cake is a promising method for converting this material into valuable energy. This work offers interesting results about the effect of equivalence ratio and temperature on the composition and quality of the produced gas obtained during olive cake gasification in a fluidized bed plant with air as a gasification agent. Additionally, the efficiency of the gasification process was evaluated. The results show that, for a specific temperature, an equivalence ratio of 0.3 showed a higher cold gas efficiency. For example, at 850 °C and an equivalence ratio of 0.1, the cold gas efficiency was 22.7%; however, at the same temperature but at an equivalence ratio of 0.3, the cold gas efficiency was increased to 61.2%. In addition, for a constant equivalence ratio, by increasing the operating temperature, there was no significant increase in the lower heating value of the exit gas, and the gas flow was practically constant with temperature, but it varied substantially with the equivalence ratio, reaching values in the range of 3.44–14.89 NL/min (825.6–3573.6 NL/kg feed). Finally, the production of CO, H2, and CH4 is estimated to be higher for tests conducted with an equivalence ratio of 0.3. [ABSTRACT FROM AUTHOR]

The utilization of coal for hydrogen generation presents a multifaceted approach employing processes like coal gasification, pyrolysis, or high-temperature steam reforming. These methodologies entail reacting coal with steam or oxygen under elevated temperatures, yielding a gas mixture comprising hydrogen, carbon monoxide, and various byproducts. This paper delves into the exploration of hydrogen generation from coal, highlighting techniques such as gasification, pyrolysis, and other emerging methods. Notably, hydrogen discoveries within coal basins have garnered significant attention due to their implications for energy production and environmental sustainability. Certain coal basins harbor deposits rich in hydrogen, surpassing conventional coal reserves in their hydrogen content. These hydrogen-rich coals, including select sub-bituminous and lignite varieties, offer promising avenues for hydrogen production and utilization. However, the utilization of coal for hydrogen generation is not without its challenges. Technical hurdles, such as process efficiency and environmental concerns, demand rigorous investigation and innovative solutions. This paper addresses the challenges faced in coal-based hydrogen generation while elucidating the potential future prospects. It explores avenues for enhancing process efficiency, mitigating environmental impacts, and integrating coal-based hydrogen generation into broader energy strategies. Moreover, it underscores the importance of interdisciplinary research and collaboration in unlocking the full potential of coal for sustainable hydrogen production. [ABSTRACT FROM AUTHOR]

The global annual production of plastics and tires exceeds 6.5 billion tons, with only 10% being recycled, leading to significant environmental problems. Thermochemical gasification of these waste materials offers a potential avenue for producing renewable hydrogen while harnessing underutilized carbon-based waste streams. This review highlights the research on thermochemical conversion of plastics and tires, providing key inferences regarding yield optimization, technical hurdles, and techno-economic viability. It indicates that strategic catalyst design and optimized integrated system configurations can significantly improve the hydrogen yields from plastic and tire pyrolysis/gasification. The key results of this work are that catalyzed gasification reactions show the most potential for maximizing hydrogen yield from plastic and tire waste. The related studies demonstrated that catalysts like Ni, Fe and Ce-doped mixtures can significantly increase hydrogen yield from plastic waste pyrolysis and gasification by suppressing coke formation and promoting reforming/shift reactions. Optimization of temperature, steam ratio and residence time also improves yield. Feedstock synergies exhibiting multiple reaction pathways likewise maximize yield. Computational modeling plays a valuable role by providing mechanistic insights through equilibrium and kinetic simulations. Integrated gasification with carbon/methane reforming shows potential to improve efficiency and lower costs. Techno-economic analyses indicate plastic/tire gasification may achieve cost parity with steam methane reforming through optimized integrated designs incorporating heat recovery. Integrated processes combining multiple conversion steps could further boost efficiency but require additional modeling and testing. A deeper understanding of reaction mechanisms, achieved through advanced modeling approaches, coupled with comprehensive lifecycle analyses of integrated solutions, can pinpoint optimized processing conditions and system designs capable of matching or surpassing the economic and environmental performance of conventional fossil fuel-based hydrogen production. The recommendations provided aim to guide future research prioritization, facilitating the realization of the large-scale potential inherent in waste-derived renewable hydrogen pathways. [Display omitted] [ABSTRACT FROM AUTHOR]

South Africa is an energy-intensive developing country in Africa and ranked as the 1st and 14th emitter of greenhouse gas (GHG) in Africa and the world, respectively. The abundance and availability of coal in South Africa make it the mainstay primary source of energy contributing 56% of national total GHG emissions. This paper focused on the duo of energy generation and emission associated with coal processing and utilization in South Africa, and the urgent need to advance coal processing technologies marked by high carbon footprints in consonance with the sustainable development goals. Different gasification techniques and their performances have been compiled and discussed. The economic, environmental impact, energetic, and exergetic characteristics of existing hydrogen production technologies for renewable and non-renewable energy sources have been examined along with hydrogen production from plasma gasification of coal. Hydrogen production via coal or coal/biomass plasma gasification technology (nuclear-, wind-, PV solar-, and concentrated solar power-driven) in addition to carbon capture technology for transforming the captured CO 2 into value-added products appears to be the most viable option to considerably reduce emissions and meet the energy demand of South Africa. This proposed technology can be pivotal to achieving a low-carbon economy (medium-term) and transition to hydrogen economy (long-term) as championed by the global sustainable development agenda. Conclusively, hydrogen (stored in different forms e.g., liquid hydrogen, ammonia, and organic hydride) seems to find more applications (in the space industry, transport, energy storage, defense industry, etc.) than coal owing to its immediate use in distribution/demand centers and remote areas. • Coal is the primary energy source of South Africa and key driver of national CO 2 emissions. • Traditional coal gasification technologies are marked by high CO 2 emissions. • Coal plasma gasification technology is a viable option for low-carbon energy economy. • Hydrogen production via coal or coal/biomass plasma gasification technology leads to zero-carbon economy. • This immensely supports the drive towards attaining the sustainable development goals. [ABSTRACT FROM AUTHOR]

Hydrogen-rich gas, characterized by high yield and purity, can be effectively generated through the steam gasification of sewage sludge (SS), offering substantial benefits for organic solid waste treatment and resource conservation. This study evaluated the gasification performance in a horizontal moving-bed reactor employing a wet-mixed CaO-red mud (CaO-RM) composite catalyst. The effects of CaO loading rate (CaO/RM), catalyst-to-SS ratio (CaO-RM/SS), and reaction temperature on the syngas yield, lower heating value (LHV), carbon conversion ratio, H 2 to CO (H 2 /CO) ratio, and H 2 yield were investigated. Results indicated that red mud loaded with a calcium-based catalyst significantly enhanced syngas production, particularly for hydrogen generation, during SS gasification. A maximum hydrogen molar fraction of 50.84% and a yield of 7.07 mol/kg were achieved with a CaO/RM of 40% and a CaO-RM/SS of 30% at 750 °C. With the reaction temperature increase from 700 to 900 °C, the catalytic performance for secondary tar cracking and steam reforming was further enhanced. The total syngas yield, H 2 yield, hydrogen molar fraction, LHV of syngas, and carbon conversion rate peaked at 0.79 m³/kg, 19.30 mol/kg, 54.41%, 10,249.48 kJ/kg, and 65.67%, respectively, at 900 °C. • Study boosts energy conversion of sewage sludge with new CaO-RM composite catalyst. • Examines effects of CaO loading rate, catalyst/SS ratio, temperature on gasification. • Prepared CaO-RM catalyst greatly increase syngas, especially hydrogen production. • Temperature rise from 700 to 900 °C boosts catalytic tar cracking and reforming. [ABSTRACT FROM AUTHOR]

This study investigates the impact of low-temperature top-lit updraft reactor chamber size on GNSBC yield and properties. For this study, the volumes of carbonization chamber (2,364, 2,013, 1,468, and 970 cm3) in a biomass-fueled TLUD biomass gasifier were varied, and the resulting biochar was analyzed using SEM, EDX, and FTIR. The novelty of this work lies in its investigation of the unexplored impact of carbonization reactor compartment size on groundnut shell biochar properties and yield, driven by the need to optimize biochar production efficiency and support sustainable waste management practices. The results showed that carbonization chamber size variation significantly affected GNSBC yield, with an initial increase followed by diminishing returns. An increase in the carbonization compartment size led to decreased carbonization duration, increased carbonization temperature, increased porosity, and decreased oxygen content. SEM analysis revealed consistent amorphous and multi-layered morphological features across BC samples, while EDX analysis confirmed high carbon content in the samples. FTIR spectroscopy confirmed the presence of oxygenated functional groups suitable for pollutant adsorption, supporting GNSBC's role in environmental remediation and industrial processes. This research contributes to optimizing biochar production efficiency, advancing circular economy goals, and sustainable waste management practices. [ABSTRACT FROM AUTHOR]

This study aims to provide an overview of the growing need for renewable energy conversion and aligns with the broader context of environmentally friendly energy, specifically through producing syngas from biomass. Unlike natural gas, which is mainly composed of methane, syngas contains a mixture of combustible CO, H2, and CnHm. Therefore, optimizing its production requires a thorough examination of various operational parameters such as the gasifying agent, the equivalence ratio, the biofuel type, and the state, particularly in densified forms like pellets or briquettes. As new biomass sources are continually discovered and tested, operational parameters are also constantly evaluated, and new techniques are continuously developed. Indeed, these techniques include different gasifier types and the use or non-use of catalysts during biofuel conversion. The present study focuses on these critical aspects to examine their effect on the efficiency of syngas production. It is worth mentioning that syngas is the primary gaseous product from gasification. Moreover, it is essential to note that the pyrolysis process (prior to gasification) can produce, in addition to tar and char, a mixture of gases. The common feature among these gases is their versatility in energy generation, heat production, and chemical synthesis. The analysis encompasses the resulting gas features, including the yield and composition, mainly through the hydrogen-to-carbon monoxide ratio and the carbon monoxide-to-carbon dioxide ratio, as well as the lower heating value and considerations of the tar yield. [ABSTRACT FROM AUTHOR]

Biochar possesses unique characteristics, including a substantial surface area, a high carbon content, sufficient capacity for cation exchange, and a robust structure. However, biochar contains hazardous pollutants like volatile organic compounds that harm soil properties and functionality. Although several studies on biochar production from various feedstocks have been undertaken in recent years, several issues about feedstock preparation, economic feasibility, influencing factors, and the proper utilization of biochar production processes need to be addressed. This paper thus addresses these issues by providing potential solutions identified through a comprehensive review. Slow pyrolysis of lignocellulosic biomass and Acacia nilotica yields biochar from 20 to 52 wt% at various temperatures and residence times. Biochar yield varies from 29 to 48.3 wt% when waste tires and corn stalks are rapidly pyrolyzed at higher temperatures and for shorter periods. Torrefaction of algal biomass at moderate temperatures with different residence times can result in a substantial yield of 50–60 wt%. However, the variability and heterogeneity of waste feedstocks pose potential challenges affecting biochar's quality and properties. Given its widespread use in carbon sequestration, soil remediation, wastewater purification, and organic waste composting, the mechanisms of biochar production in environmental usage need to be investigated. [ABSTRACT FROM AUTHOR]

This paper presents an innovative mathematical model of solid fuel gasification, which is not described in the available literature. The calculation of the components of the heterogeneous phase (including both solid and gaseous phases) as well as the calculation of the homogeneous phase (only gaseous components) is based on the balance of the total amounts of carbon, oxygen, hydrogen, and nitrogen entering the reactor space. Additionally, this paper introduces a new method for calculating the composition of the gaseous phase, based on reducing the heterogeneous mixture (composed of solid and gaseous phases) to a homogeneous gaseous phase. This approach to calculating the gaseous phase composition in the solid fuel gasification process has not been found by the authors in the cited literature. This paper also presents a model for calculating the heterogeneous and gaseous phases using the number of moles that participate in the assumed chemical reactions of the solid fuel gasification process. This approach to calculating the composition of the heterogeneous and gaseous phases of the solid fuel gasification process is also not represented in the cited literature. For comparison with the literature data, municipal solid waste (MSW) and cashew nut shell (Cashew Shell Char (CNSC)) were used as fuels in the calculation of gasification composition. The results of the calculation of the gaseous phase composition using the model presented in the paper show good agreement with the data from the literature. The calculation of the composition of the heterogeneous mixture during the steam gasification of MSW (α = 0.4) shows the presence of a solid phase (carbon) up to approximately 735 °C. At that temperature, the synthetic gas contains only gaseous components: CO = 33.10%, H2 = 52.70%, CH4 = 2.54%, CO2 = 4.97, H2O = 5.93% and N2 = 0.76%. Increasing the temperature above 735 °C eliminates the solid phase from the equilibrium mixture. The literature data on solid fuel gasification generally do not consider the proportion of the solid phase (carbon) in the equilibrium mixture. To satisfy the material balance at the input and output of the gasification reactor, it is necessary to determine the proportion of the solid phase (carbon) in the equilibrium mixture. Since the proportion of the solid phase (carbon) in the heterogeneous equilibrium mixture can only be determined through measurement, the development and application of a mathematical model in engineering practice is of great importance, so this developed model can be considered a useful tool for simulating the influence of process parameters on gas characteristics. [ABSTRACT FROM AUTHOR]

Despite the increasing global need for sustainable energy, biomass gasification is becoming a highly promising method for transforming raw biomass into usable energy. The present review article analyzes the essential aspects of biomass‐based energy production, starting with an assessment of existing energy needs and the crucial contribution that biomass can make in fulfilling these demands. The research investigates recent advancements in several biomass gasification methods, explaining their mechanics and discussing the related difficulties. The research conducts a thorough evaluation of the efficiency, yield, and environmental consequences of biomass gasification, aiming to determine the feasibility of the technique. In addition, the study rigorously assesses the techno‐economic factors of energy generation from biomass, providing valuable information on the economic viability and scalability of various biomass gasification techniques. The present study is focused on providing a comprehensive understanding of biomass gasification by analyzing current improvements and conducting a techno‐economic comparison to make well‐informed decisions for a sustainable energy future. [ABSTRACT FROM AUTHOR]

Accurate measurement of heterogeneous reaction kinetics in thermogravimetric analysis (TGA) requires accurate estimation of concentration and temperature in the sample. However, this information is difficult to estimate during the measurement, especially at high temperatures and pressures. Computational Fluid Dynamics (CFD) is used to perform a comprehensive analysis of the temperature and species distribution throughout a high‐temperature, high‐pressure test rig, including temperature and species transport within the probe sample. The temperature and gas concentration within the sample are accurately calculated by CFD, providing a much deeper insight into the local temperature and species distribution. The numerical results show a significant decrease in gas concentration and temperature in the core region of the packed bed, indicating that bed diffusion dominates the overall conversion for the char reaction studied in this article. The re‐evaluation based on the model considers the limitations of heat and mass transfer at each measurement point. This forms the basis for a novel, model‐driven approach that derives heterogeneous kinetics from TGA measurements with significantly improved accuracy and reliability. [ABSTRACT FROM AUTHOR]

This study determined the toxicity of the condensates produced during the gasification of two waste types. Coffee grounds, pine pellets, and a mixture of both substrates at a ratio of 1:1 were used in the study. Two microbiotests were applied for soil plants and aquatic macrophytes, and quantitative analysis of the soil microbiome for primary taxonomic groups of microorganisms was conducted. Three contamination rates were used in the Phytotoxkit test and the microbiological tests, 100, 1000, and 10,000 mg·kg−1 d.m. of soil, while in the aquatic organism studies, successive two-fold serial dilutions of condensates were used. The presence of liquid waste from the gasification process adversely affected the germination and development of terrestrial plants and the vegetative growth of aquatic plants. The condensate components modified the composition of the soil microbiome, adversely affecting soil fertility. The negative impact increased with increasing levels of contamination and primarily depended on the type of substrate from which the gasification process produced the liquid waste. [ABSTRACT FROM AUTHOR]

This study aims to investigate the effects of different catalysts on biomass gasification. Therefore, red mud (RM) and Aluminum–Nickel alloy were used as catalysts with biomass mixture (BM) for the lab-scale gasification studies by using an updraft and a modifiable-downdraft fixed bed reactor. The maximum volumetric percentage of H 2 , ranging from 51% to 65%, was achieved at 900 °C in both gasifiers. Al–Ni catalyst significantly boosted H 2 content, reaching 65% in the updraft gasifier at 900 °C with 0.05 L/min dry air. H 2 /CO ratio varied from 2 to 4 for BM, while catalyst use expanded the range to 1.6–7 with the Al–Ni catalyst demonstrating the most effective performance. In general, it was seen that RM increased the H 2 component in the syngas between 1 and 7 vol% at 900 °C in updraft gasifier. In the modifiable-downdraft reactor, on the contrary, H 2 concentration in the syngas decreased by 2–6% with the addition of RM. [Display omitted] • Red mud and aluminum - nickel alloy were added to biomass as catalysts. • Two different fixed-bed gasifiers were operated under the same conditions. • The use of the catalyst increased the H 2 vol% in the syngas. • The max. volumetric percentage of H 2 gas was found to be in the range of 51–65%. [ABSTRACT FROM AUTHOR]

Biorenewable hydrogen is requisite to replace non-renewable hydrogen. Decarbonization is assured. Hydrogen demand is severely rising due to mitigating climate change and reducing fossil fuel dependency. Green Hydrogen from agro waste proposition makes bio-circular economy upcycling. The main objective of this study is to reinforce the hope of renewable, sustainable H 2 production from agro-waste. Initially, this paper shows the demand for green hydrogen, the sustainable availability of agro waste, and their capability to produce H 2. Insights into the gasification of agro waste about cellulose, hemicellulose, and lignin with conventional gasification. The effect of catalyst and supercritical gasification and their challenges is discussed. Most uniquely, other reviews highlight various aspirations behind agro-waste gasification to attain a strong business model, such as co-production, co-gasification, and CO 2 reforming with H2 yield. This review exhibits some main insight into various aspects of agro-waste gasification. H 2 from agrowaste gasification has high energy content (122 kJ/g) and high energy conversion efficiency in the range of 55–58 %, in addition to gaining the economic penalties of 2.2–2.5 net points for decarbonization. Agro waste is composed of lignocellulosic material that is relatively richer in hydrogen than fossil fuel resources. In SCWG, water is one of the natural solvents, which means feedstock effectively dissolves with water solvents. Intermittent density, low viscosity, and surface tension are nearly zero values due to SCW having no specific phase boundary, which enhances the gasification and substantially reduces tar formation during SCWG. Catalyst utilization enhances H 2 production. The present study comprehensively exhibits the role of catalyst and their supporter and promoter. Ni-based catalysts are mostly suggested for H2 production but fall into reusability issues. The main reason behind this is that Ni is inefficient in removing HCl, H 2 S, and total trace elements during gasification. Recently, low-cost and waste-to-wealth transformation aspects of biochar-based catalysts have gained attention. Renewable-assisted gasification significantly improves the energy and exergy of the system and suppresses the important concern of energy consumption during gasification. Renewable assisted and various aspiration incorporation into gasification is solidly recommended for future implementation based on energy, economic, and environmental benefits from them. Plastic and biomass are richer in hydrocarbon and oxygen, respectively; this synergistic effect has the potential to enhance the H 2 yield. From this study, PP plastic is mostly preferred for co-gasification with biomass. Compared to 100 wt% of biomass, the introduction of plastic slightly increased the coke formation, but the H 2 yield was improved. When the plastic mixture of 10 wt% increases coke deposition, however, significant coke deposition is not reported when 20 wt% of plastic concentration is not reported. Carbon capture via CO 2 inert gas supply enhances the H 2 yield, provides a route to carbon trade, and substantially contributes to GHG pollution mitigation. Agro-waste gasification is produced by a product that has the potential to be used in a wide range of applications due to its unique properties, such as large specific surface area, porosity, functional groups, high reliability, and minimum cost. Hopefully, this review will be an optic to the most appropriate green hydrogen production path for sustainable clean energy production and effective agro-waste management. • This review acts as an optic to the most appropriate green hydrogen production path. • Hydrogen separation, purification, and storage need more care. • Carbon dioxide reformation aids a carbon trading system and reduces environmental effect. • These research provide direction for energy nexuses that may be derived from agricultural waste. [ABSTRACT FROM AUTHOR]

Scientists are currently focusing on eco-friendly and non-polluting fuels, and the production of H2 from biomass has recently garnered attention. Valorization of biomass via catalytic gasification has been proposed as a potential solution to the environmental problems associated with CO2 emissions and global warming. Nonetheless, the process generates tar as a by-product, which poses numerous difficulties for the reaction process. Recently, steam reforming has become a promising method for tar conversion since steam potentially contributes more H2 to the reaction. However, the reaction is endothermic and hence requires the use of a catalyst. This leads to the global challenge which is designing an affordable anti-coking sintering resistance catalyst. This review reports on advances made in the development of catalytic biomass tar reforming, focusing mainly on toluene as the biomass tar model compound. Recent developments in the toluene catalytic steam reforming, reaction pathways, catalyst deactivation studies, and catalyst development were comprehensively reviewed. In addition, the functions of active sites, support, and promoter in the performance of toluene steam reforming were discussed concurrently. The review concluded with an insight into the prospects and challenges of biomass tar reforming technology, as well as a few recommendations for future catalyst development. [ABSTRACT FROM AUTHOR]

Gasification of soy hull pellets was carried out in a pilot-scale fluidized bed gasifier under different operating conditions. The experiments were designed to determine the effect of four operating parameters: biomass loading (10–30 wt.%), temperature (750–950 °C), equivalence ratio (0.2–0.4), and fluidization velocity (2.5–4.0 Uff) of the fluidizing gas, on the quality of syngas produced. The interaction between each operating parameter and how they affect syngas quality were also considered using statistical analysis and optimization done via desirability analysis. The syngas quality and gasification performance were measured with respect to the H2:CO ratio, gas yield, carbon conversion, and the cold gas efficiency. The hydrodynamics of the fluidized bed binary mixture at the operating conditions and how the syngas quality was affected were also discussed. Temperature showed the maximum significant effect on the syngas quality with the higher temperature favoring higher H2:CO ratio values as well as gas compositions. High loading of up to 30% in the binary mixture of the fluidized bed was successfully achieved due to the modified nature of the biomass, resulting in higher gas yields. Higher temperatures resulted in higher gas yield and carbon conversion while increasing the equivalence ratio led to lower cold gas efficiency. Gas yields of ~ 4 m3/kg and carbon conversion of ~ 90% were achieved from different combinations of the operating parameters. [ABSTRACT FROM AUTHOR]