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Coal-based chemical looping gasification (CCLG) has been proposed as an emergent type of coal gasification technology that produces high-quality syngas by using lattice oxygen from oxygen carrier instead of molecular oxygen. In this paper, the Fe–Ni composite oxygen carrier was synthetized using sol-gel method and the gasification performance of the prepared sample was analyzed by a fixed-bed reactor. The results indicated that the Fe–Ni composite oxygen carrier presented a high carbon conversion of fuel and syngas selectivity during the CCLG process. Additionally, the cycle stability test showed that the carbon conversion of fuel and syngas selectivity did not change significantly with the increase of cyclic frequency. To further study the influence of volatiles released from coal on the gasification performance of oxygen carrier, the interactions between the oxygen carrier samples and char obtained at different pyrolysis temperatures were investigated by a fixed-bed reactor and TG-MS, respectively. The results suggested that the gas products (H 2 , CO, CO 2 and CH 4) yields of char-oxygen carrier were significantly lower than those of coal-oxygen carrier. Besides, the pyrolysis temperature for preparing char had a great effect on the carbon conversion of fuel and syngas selectivity due to the distinction of volatiles released from solid fuel. • Efficient Fe–Ni composite oxygen carrier was crafted via sol-gel method. • Fe–Ni composite oxygen carrier showed good performance with desirable reactivity and cyclic stability. • Interaction between oxygen carrier and volatiles released from coal was investigated. • Char gasification was demonstrated to be the rate determining step during the CCLG process. [ABSTRACT FROM AUTHOR]

The selection of sustainable hydrogen production technologies (HPT) is a paradigm transformation for industrial enterprises to pursue commercial benefits and environmental performance, which has increasingly attracted the attention in academic circles. Therefore, the chief orientation of this research is to construct a novel sustainability-oriented decision-support framework for hydrogen production system. Firstly, an approach is developed to determine expert weights under each criteria in a linguistic environment. Secondly, the Measurement of Alternatives and Ranking according to Composite Solution (MARCOS) method is extended to prioritize sustainable HPT under hybrid information (HMARCOS). Finally, a case study of 5 typical HPT regarding 15 sustainability indicators is conducted. The results display the biomass gasification has the highest sustainability priority for hydrogen production compared with wind turbine electrolysis, photovoltaic electrolysis, steam methane reforming and coal gasification. Furthermore, the reliability and availability of the integrated framework is demonstrated by the comparisons with other approaches. • A complete HPT sustainability criteria system has been established. • A method is presented to determine the DM weights under each criteria. • The HMARCOS model is extended for evaluating the sustainabable potential of HPTs. [ABSTRACT FROM AUTHOR]

This paper presents a detailed review of the plasma gasification process for waste disposal. Due to Shifting economies and consumerism culture, ample change can be seen across the globe in the form of rapid industrialisation and burgeoning urbanisation, which results in a massive increase in waste generation. Plasma gasification technology is an emerging solution for processing a wide range of waste making it a highly sustainable, efficient, and ecologically sound process. This literature review discusses the feasibility of the plasma gasification method and its superiority over other conventional waste disposal techniques. A comprehensive analysis of different methods of plasma generation for gasification is done in this literature review. The review paper presents a detailed coverup of the entire process of plasma gasification and post-processes. The article discusses the notable advancement, current scenario, and possibilities in plasma gasification methodology in terms of the design of plasma torch, modelling of gasifiers, generation of syngas, and power production. It provides an overview of advanced simulation tools helpful in the analysis of the Waste-to-Energy (WtE) process. This literature review aims to provide an overview of the recent advances in plasma gasification, highlighting the technical aspects, environmental benefits, and economic viability of the technology. It also reviews the latest research and developments in plasma gasification and discusses the challenges and limitations of the technology, as well as the future prospects and potential applications. • Plasma gasification methodology for waste treatment is discussed in detail. • Prominent thermal and non-thermal practices are discussed and compared in this literature review. • Selective use of plasma gas for enhanced efficiency and optimised gas yield/composition. • Hybrid systems offer versatility in processing diverse feedstocks and can achieve higher energy efficiencies. • Plasma-catalysis approach with NTP shows desirable syngas yield. [ABSTRACT FROM AUTHOR]

The challenge for efficient management of post-consumer plastic and biomass waste has grown over the past few decades due to their dramatic increases. In comparison to conventional gasification, microwave-assisted co-gasification of plastics and corn stover offers many benefits, including increased H 2 yield and gas components compared to unfavorable char/tar. Nonetheless, for future commercialization of the process and ease of product separation, further reduction of the undesirable tar is necessary, which can be achieved over the catalytic route. In this work, we studied the catalytic effect of magnetite for microwave-assisted co-gasification of corn stover and plastic to make syngas with higher H 2 and lower tar selectivity over non-catalytic conditions. A 1:1:1 ratio of plastic-corn stover-magnetite was used to evaluate the reaction parameters such as temperature, space velocity, heating media, and catalytic cycles under gasification conditions. In comparison with the microwave non-catalytic route, a 100% increase in the total H 2 yield with 76% higher H 2 production efficiency (mmol/kWh) was achieved in the presence of the magnetite catalyst, while reducing the overall tar formation from 9% to 2%. When magnetite was reduced in situ during the reaction, it coupled with microwave and delivered oxygen radicals that cracked down plastic and corn stover intermediates generated from the synergistic effect under microwave heating. Soon after the oxygen transfer process initiated, magnetite reached its final oxidation state consisting of microwave-active Fe and Fe 3 C phases that continued coupling with microwaves along with the generated graphitic carbon to maintain the heat necessary to further reduce the generated tar and make additional gaseous products, as confirmed by XRD, Raman, and TGA analyses. [Display omitted] • Catalytic co-gasification of waste feedstock was demonstrated using microwave energy for production of clean hydrogen • Catalyst and microwave synergy doubled the H 2 production compared to non-catalytic reaction with 76% higher H 2 production efficiency (mmol/kWh) • Catalytic gasification reduced the tar yields from 9% from non-catalytic reactions to 2% • Magnetite delivered oxygen radicals that cracked down plastic and corn Stover intermediates • Synergy between microwaves and catalyst + feedstock resulted in H 2 -rich syngas with reduced tars [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 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]

The current work focuses on the usage of a sustainable fuel derived from Senna auriculata seed through pyrolysis for IC engine applications. Batch-type reactor was employed to produce the bio-oil through pyrolysis, and it was found that the optimum temperature of 550 °C is suitable for a maximum yield of 46%. Physical characterization of the produced SA oil is examined as per ASTM standards, and chemical characterization is studied using FTIR, 1HNMR, and GC–MS analysis to study and compare with conventional diesel. The performance of the engine, along with combustion and emission analysis, was carried out with blends of SA and diesel. The results investigated were compared with those of conventional diesel. The efficiency for the SA10 blend was estimated to be 34.5%, which is 1.27% higher than regular diesel fuel under full-load conditions. Emission analysis portrayed the CO and UHC emissions as low, whereas the increase in NOX emissions was due to the high temperature inside the cylinder and the presence of oxygen. The SA10 blends exhibited comparable performance and emission results with commercial diesel fuel under normal working conditions. This research provides an integrated approach to selecting the precise biomass and establishing sustainable bioenergy recovery as the future energy resolution. [ABSTRACT FROM AUTHOR]

The demand for fossil fuels is rising rapidly, leading to increased greenhouse gas emissions. Hydrogen has emerged as a promising clean energy alternative that could help meet future demands way sustainably, especially if produced using renewable methods. For hydrogen to meaningfully contribute to energy transitions, it needs more integration into sectors like transportation, buildings, and power that currently have minimal hydrogen usage. This requires developing extensive cross-sector hydrogen infrastructure. This review examines hydrogen combustion as a fuel by exploring and comparing production techniques, enriching ammonia with hydrogen as a CO 2 -free option, and hydrogen applications in engines. Additionally, a techno-economic environmental risk analysis is discussed. Results showed steam methane reforming is the most established and cost-effective production method at $1.3–1.5/kg H 2 and 70–85% efficiency but generates CO 2. Biomass gasification costs $1.25–2.20/kg H 2 and pyrolysis $1.77–2.05/kg H 2 offering renewable options. However, bio-photolysis currently has high costs of $1.42–2.13/kg H 2 due to low conversion rates requiring large reactors. Blending H 2 /NH 3 could enable carbon-free combustion, aiding carbon neutrality pursuits, but minimizing resultant NOx is crucial. Hydrogen's wide uses from transportation to power underline its potential as a transformational energy carrier. [ABSTRACT FROM AUTHOR]

Methanol is industrially generated from non-renewable fossil fuel sources. Owing to its widespread use in all domains, from synthesis of various chemicals to its use as an alternative fuel in the SI engines, finding a sustainable and renewable way of generating methanol would be one of the key achievements. Biomass-derived syngas for methanol generation would be one such example. However, bio-syngas has few drawbacks like (a) lower H 2 content when compared to the traditional SMR syngas, (b) the impurities present in bio-syngas are higher and need removal, (c) the biomass availability is scattered, just to name a few. In this work, we will be addressing the low H 2 -containing syngas for methanol generation process. Since limited literature is available on the experimental work on methanol generation from bio-syngas (without H 2 adjustment), this work aims to bridge the research gap by presenting experimental results on direct bio-syngas to methanol generation process. This work will address the experimental comparison between two syngas compositions: one H 2 excess and the other H 2 deficient. The composition of the first syngas, namely syn-1, used is like the one obtained from the SMR process. The composition of the second syngas, syn-2, is via the biomass gasification process. The H 2 /(CO+ CO 2 ) values in syn-1 and syn-2 were 3.54 and 1.08, respectively. The experimental setup consisted of a high-pressure microreactor, and a Cu/ZnO/ Al 2 O 3 commercial catalyst was used for the methanol generation process. The results from the experimental work were used to develop and validate the Aspen Plus® kinetic model. The validated model for lower H 2 -containing syngas for methanol generation process would be further used for the formulation of mathematical equation for methanol yield predictions. The experiments performed indicated that the methanol yield is favored at lower temperatures and higher pressure values of 483 K and 5 MPa for both syn-1 and syn-2. The results also indicated that the high CO 2 /CO ratio results in increased side reactions. The observed increase in the CH 4 selectivity in syn-2 when compared to syn-1 was the evidence for this increased side reactions. This is one of the key highlights as for SMR syngas-to-methanol conversion the CH 4 is sometimes assumed to be inert. Finally, the developed mathematical model predicted a maximum methanol yield of 21.06% for lower H 2 syngas at a temperature of 483 K, a pressure of 5 MPa and a space velocity of 1650 ml/h(g cat). The mass balance analysis suggests using 2.27 kg of syn-1 and 5.67 kg of syn-2 for production of one kg of methanol under a similar condition of 483 K, 5 MPa and 1650 ml/h(g cat). This validated model for methanol production will find its utility for methanol yield optimization and techno-economic analysis. [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]

[Display omitted] • Steam gasification of a genetically modified (GMO) rice straw is investigated. • GMO rice straw exhibits superior gasification performance compared to regular one. • Co-gasification of GMO rice straw with Giant Miscanthus is investigated. • Seaweed biochar addition can greatly enhance co-gasification with reduced tar. • Promoting synergistic effect by low-cost catalyst for co-gasification is clarified. Future sustainability visions include clean, renewable energy from hydrogen, which can be produced, among other ways, by biomass steam gasification. This study explores strategies addressing the limitations in steam co-gasification of herbaceous biomass, using Monster-TUAT1 rice straw, a genetically modified rice plant with a taller and bigger stalk developed by Tokyo University of Agriculture and Technology (TUAT), and Giant Miscanthus, a promising energy crop, as the feedstock. Firstly, compared with the typical rice straw, the Monster TUAT1 demonstrated superior steam gasification performance with a 1.75 times higher hydrogen gas yield and 27.0 % less tar generation. With a focus on overcoming the challenges posed by high silica content in the Monster TUAT1, co-gasification of it with an energy crop of Giant Miscanthus was performed. However, even under the optimum operation condition (750 °C, steam flowrate: 0.15 g/min), the hydrogen gas yield was only 29.3 mmol/g-C with a tar yield of 27.6 %wt. and a carbon conversion efficiency of 45.9 %, which is deemed unsatisfactory for hydrogen production. Thus, strategies for enhancement were proposed, including the incorporation seaweed biochar with high alkali and alkaline earth species, calcined scallop shell powder, and alkali metal salt into the gasifier. Consequently, the introduction of 10 %wt. of calcined scallop shell resulted in an increase in H 2 yield to 37.0 mmol/g-C and 24.3 % CO 2 reduction. The addition of alkali metal salt led to 43.9 % increase of H 2 product with a 15 %wt. tar yield. The most significant improvement occurred with the introduction of seaweed biochar at 50 %wt., increasing of the hydrogen gas yield to 62.0 mmol/g-C with 86 % of carbon conversion efficiency and tar reduction to 5.5 %. These findings demonstrate the viability of utilizing herbaceous biomass such as rice straw in conjunction with the strategic solutions of co-gasification to overcome constraints in improving hydrogen production. [ABSTRACT FROM AUTHOR]

Gasification, which refers to the partial oxidation of a solid carbon-based fuel in a temperature range of over 700 °C, is a promising route to convert biomass into H 2 -rich syngas. In this work, a detailed ASPEN plus model for biomass gasification with different oxidants (air, oxygen-enriched air, air/steam and oxygen-enriched air/steam). The accuracy of the developed model was confirmed by comparison with two sets of experimental results obtained from air and air/steam experiments, yielding a root mean square error (RMSE) of 1.42 and 2.42, respectively. Variations of equivalence ratio (ER) in a range of (0.22–0.31), temperature (700–1000 °C), oxygen percentage in the air, OP (21–50%), and steam/biomass ratio, SBR (0–1.5) were studied on the gasification of sawdust to optimize the process. A rise in OP led to an increase in H 2 production, char conversion and tar cracking, but an opposite trend was observed for the gas yield, due to the reduced N 2 dilution. The maximum H 2 content was obtained when oxygen-enriched air/steam was used as oxidant due to having both advantages of reducing N 2 dilution and promoting water-gas shift (WGS) reaction. Increasing ER, SBR and temperature all contributed to increased gas production and tar cracking, but degraded the quality of syngas. H 2 content was significantly enhanced at T < 900 °C and later showed negligible changes when the temperature exceeded 900 °C as a result of continuous oxidation reactions. At optimal operational conditions (OP = 40%, SBR = 1.0, ER = 0.28 and gasification temperature = 1000 °C), a maximum H 2 content of 20.44 vol% could be attained. • A kinetic model was developed to simulate biomass gasification with various gasification agents. • The predicted results were validated against available experimental data in the literature. • A rise in OP led to an increase in tar cracking, but an opposite trend was observed for gas yield. • The maximum H 2 content was obtained when oxygen-enriched air/steam was used as gasification agent. • OP = 40%, ER = 0.28, SBR = 1.0 and T = 1000 °C are considered as optimal conditions. [ABSTRACT FROM AUTHOR]

Co-gasification of coal and biomass in a bubbling fluidized bed may offer an effective and economical method to partially replace coal to produce hydrogen, thereby addressing the objectives of achieving a carbon dioxide emissions peak and carbon neutrality. An Artificial neural network (ANN) model was utilized to simulate the hydrogen and other performance of co-gasification in the bubbling fluidized bed. Five types of ANN architectures were tested, including FFBP, CFBP, EFBP, LR, and NARX. Five optimization algorithms were also applied, including L-M, GA, GD, GDX, and PSO, to identify the optimal model to give a more accurate predicate the hydrogen production. The input data were derived from the ultimate analysis of the mixed coal and biomass, the proximate analyzes of mixed coal and biomass, and the operational conditions. The output data consisted of gas composition, carbon conversion, gasification efficiency, total gas yield, syngas yield, low and high heating values of the gas. The LR-PSO with 6 hidden neurons (R2 = 0.9995 and MSE = 0.1357) outperformed other ANN types and optimization algorithms. To further understand the performance of co-gasification, the influences of biomass to coal ratio, equivalence ratio, steam to carbon ratio and temperature on ratio of H 2 to CO and syngas yield were predicted. The highest ratio of H 2 to CO for the work of Li et al. (2010) [26], Song et al. (2013) [27] and Valdés et al. (2015) [28] were 0.7, 1.2 and 0.88, respectively. And those for syngas yield were 0.85, 1.09 and 1.55 m3/kg, respectively. To reveal the important factor on the ratio of H 2 to CO, a detailed analyzed of the contribution ratio was conducted. The most critical factor affecting co-gasification performance in the work of Song et al. (2013) [27] were identified as SC ratio and temperature, which was higher than those of W and ER. The effect of SC exceeded that of T at SC ratio of 0.4, while it came to a reverse at temperature above 700 °C. These findings may serve as a valuable tool for adjusting the various factors to achieve the desired performance in the co-gasification of coal and biomass. [Display omitted] • An ANN model of co-gasification performance was developed in a bubbling fluidized bed. • Layers Recurrent showed better performance than other ANN types. • The Particle Swarm Optimization showed better performance than other optimization algorithms. • A comprehensive analysis was conducted on the H 2 /CO ratio. • The most critical factor affecting co-gasification performance was identified as steam to carbon ratio and temperature. [ABSTRACT FROM AUTHOR]

This study explores a novel approach that combines soil recovery with biofuel production, presenting a strategy that addresses the increasing demand for biofuels while sidestepping the food–fuel debate. It also introduces an innovative method for recovering heavy metals from soils through their translocation into the solid product of the conversion process. Phytoremediation trials were conducted under real field conditions, and the thermochemical conversion of the harvested biomass was carried out at lab scale. Field trials took place in 2021–2023 in Lithuania and Serbia. In Serbia, the contamination primarily involved heavy metals, whereas the Lithuanian site was predominantly contaminated with hydrocarbons from petroleum products. The harvested biomass underwent pretreatment and was then used as feedstock for conversion into high‐energy carriers. The conversion products were evaluated for their potential to substitute fossil fuels. Finally, the value chain, encompassing key stakeholders and factors impacting the profitability of this approach, was established, and initial estimates were made regarding the size of individual cost components. [ABSTRACT FROM AUTHOR]

Reductions in greenhouse gas emissions are necessary to slow global warming and decrease the likelihood of irreversible climate scenarios. There is thus an urgent need for low‐emissions fuels. This study conducted a techno‐economic analysis of two different industrial plant concepts for producing hydrogen from woody biomass. One was a large‐scale centralized 60 MWH2 option using dual fluidized bed gasification with CO2 removal. The other was a small‐scale decentralized 1 MWH2 option using fixed‐bed gasification without CO2 removal. Mass and energy balances were calculated by the process simulation software IPSEpro. Key performance indicators, including technical, economic, and environmental parameters, were derived. Overall energy efficiencies of 64.2 and 59.5% and hydrogen yields of 87 and 68 gH2 kg−1BM.db were determined for hydrogen production by dual fluidized bed and fixed‐bed gasification, respectively. The levelized costs of hydrogen amounted to 5.6 and 15.0 €2022 kg−1H2 and agreed quite well with values from the literature. Flexible and decentralized heat, electricity, and hydrogen production based on fixed‐bed gasification within a multiproduct plant were also evaluated. The results show that the multiproduct plant could be economically feasible if at least 63% of the annual operating hours were dedicated to hydrogen production, and assuming a hydrogen selling price of 17.5 €2022 kg−1H2 in Austria. In conclusion, both of the processes that were evaluated are conceivable technologies for the transition of the energy system towards renewable energy sources from a technical and economic point of view, although small‐scale hydrogen production is considerably more expensive. [ABSTRACT FROM AUTHOR]

This work studies red mud, a residue from the processing of bauxite, as a support catalyst in the thermocatalytic reforming (TCR) process, using wood, digestate, and straw as case studies. Thermocatalytic reforming is a thermochemical process for the conversion of biomass into biofuels, combining intermediate pyrolysis and catalytic reforming and resulting in high‐quality biofuels. The quantity and quality of the catalyst in the postreformer is vital as it influences the reactions taking place in it. Normally, nonreactive components of the char produced in the process act as the catalyst in the postreformer but adding a support catalyst may improve the products. In this work, red mud is introduced in the process by mixing it with the feedstock in a ratio of 1:3. The results, in comparison with normal TCR experiments on the same feedstock materials, show that the introduction of red mud into the process generally reduces the biochar yield and generally increases the biogas and product water yields, and the bio‐oil yield remains constant. Its introduction also increases the hydrogen fraction of the gas and tends to reduce the nitrogen and sulfur content of the products, thus improving their quality. These observations are consistent across feedstock materials and postreformer temperatures. The results therefore suggest that red mud is a good support catalyst for increasing the gas yield, increasing the hydrogen fraction of the gas, and improving the quality of the products from the TCR process. [ABSTRACT FROM AUTHOR]

In recent decades, growing energy demand, coupled with concerns about climate change, has led to the exploration of sustainable energy sources. Among these, biomass gasification stands out as a promising method for generating heat and power. This research delves into the potential impact of biomass gasification within the global energy landscape, focusing particularly on its application in cogeneration plants. Utilizing Aspen Plus software V10, this study undertook the modeling and optimization of a biomass cogeneration plant. Through simulation, it was found that a biomass flow rate of 5 kg/s yielded 6.172 MW of power output. Additionally, the study revealed several key factors that influence power generation: increasing biomass and airflow rates, increasing gasification temperature, and reducing water flow rate. By doubling the biomass flow rate to 10 kg/s and increasing the temperature to 800 °C, power generation increases by 41.75%. Moreover, the study demonstrates that Portuguese municipal waste is an efficient source of energy production, with higher cold gas and overall efficiencies compared to forest and vine-pruning residues. [ABSTRACT FROM AUTHOR]

Lock-in to existing assets and business practices is a major obstacle to the global objective of phasing out coal-fired power to accelerate decarbonization towards Paris Agreement goals. Japan has attracted attention in previous literature, with several studies demonstrating how market and political conditions have propelled investments in new coal-fired power plants while raising barriers to achieving a phase-out. But in addition to market-level conditions, firm-level characteristics – including assets, commitments, investment behaviour and future-oriented innovation activities – are also critical determinants of lock-in vulnerability. To deepen understanding of how such firm-level dynamics might affect the power industry, this empirical study takes the case of ten incumbent utilities in Japan to identify and compare potential sources of coal lock-in. We leverage diverse quantitative and qualitative data to assess the state of: (1) management, assets and operational factors; and (2) the development and deployment of next-generation coal technologies. Through this two-fold approach, we demonstrate how current conditions and future-oriented activities are likely to reinforce tendencies to continue using coal in coming decades, thereby hampering the emergence of phase-out ambitions. These findings harbour important implications for climate policy and the urgent need to end coal burning in the power sector. Japan's major power utilities all intend to maintain coal in power mixes while transitioning to net-zero by 2050, aiming to eliminate carbon emissions rather than coal-fired power per se. Ambitions to reduce dependence on coal are weakened by a multitude of potential lock-in sources across individual utilities. All utilities are attempting to commercialize next-generation technologies such as co-firing with ammonia and biomass, carbon capture and coal gasification. Phasing out coal in Japan thus requires climate policies that incentivize the development and diffusion of non-emitting power sources that offer faster emissions reduction than expensive and unproven technologies. [ABSTRACT FROM AUTHOR]

Coal holds a significant position in China's energy consumption structure. However, the release of Hg0 during coal combustion poses a serious threat to human health. Traditional activated carbon for Hg0 removal is expensive; finding efficient, inexpensive and renewable adsorbents for Hg0 removal has become a top priority. Rice husk gasification char (RHGC) is a solid waste generated by biomass gasification power generation, which, loaded with silver to remove Hg0, could achieve the purpose of waste treatment. This paper examines the Hg0 removal performance of silver-loaded rice husk gasification char (SRHGC) under different operating conditions through experimental analysis. This study employed quasi-first-order, quasi-second-order, and internal diffusion kinetics adsorption equations to model the amount of Hg0 removed by SRHGC at different temperatures, thereby inferring the reaction mechanism. The results indicate that Hg0 removal efficiency of SRHGC increased by about 80%. The Hg0 removal ability was directly related to silver load, and the amount of Hg0 removed by SRHGC did not a exhibit a simple inverse relationship with particle size. Additionally, the Hg0 removal efficiency of SRHGC declined with increasing adsorption temperature. The removal of Hg0 by SRHGC conformed to the quasi-second-order kinetic equation, with the adsorption rate constant decreasing as the temperature rose, consistent with experimental observations. This paper provides both experimental and theoretical references for future modification and optimization of RHGC for coal-fired flue gas treatment, and also offers valuable insights into Hg0 removal by carbon-based adsorbents. [ABSTRACT FROM AUTHOR]

Paddy parboiling in rice industries is an energy-intensive process that requires huge attention for energy conservation, fuel economy, and sustainability. Thus, several research initiatives have been undertaken to adopt a suitable energy conversion system in such industries to improve thermal efficiency and reduce environmental impact. In this study, exergy performance and exergy-based sustainability indicators have been investigated on a reversible bed paddy dryer coupled with a rice husk-fuelled downdraft gasifier. The experiment was conducted at the optimum operating conditions such as an equivalence ratio of 0.2 in the gasifier and a drying air temperature of 80℃ in the dryer. The exergy efficiency of the reversible bed dryer and the gasifier were 65.53% and 70.92% respectively. The lowest exergy efficiency of 35.29% was seen in the combustion chamber since a huge exergy destruction of 2.75 kW occurred. Therefore, the combustion chamber has a high potential improvement of about 1.66 kW. Due to less exergy destruction, the gas cooler and air duct showed high exergy efficiency of 62.36% and 76.2% respectively and the lowest values in exergy-based sustainability indicators. The assessment of environmental and sustainability factors on each component showed that the combustion chamber has a high waste exergy ratio of 0.688, environment effect factor of 1.95, exergy destruction coefficient of 0.69, and exergy sustainability index of 0.51. [ABSTRACT FROM AUTHOR]

The conversion of biomass residues into syngas through gasification is attractive for energy and process industry applications. However, transportation, storage, and operational challenges limit the conventional direct solid biomass gasification process. To address these issues, the intermediate conversion of biomass to bio‐oil has emerged as a promising alternative. Bio‐oil offers improved transport and storage capabilities due to its higher mass and energy density, enabling the decoupling of solid biomass supply and syngas demand. This study compares two routes for syngas production: direct gasification of solid biomass and indirect gasification using bio‐oil from biomass pyrolysis as an intermediate with biochar and pyrolysis gas supplying thermal energy to the pyrolysis stage. Biochar combustion provides about 1.4 MJ kg−1 of dry biomass to maintain the pyrolysis temperature at 480°C. Using AspenPlus® simulations, the composition and Low Heating Value of the syngas produced by both routes are analyzed. Energy and exergy analysis at different equivalence ratios and temperatures revealed that direct gasification has higher efficiencies than indirect gasification. At 1000°C and an equivalence ratio of 0.4, the highest energy and exergy efficiencies occurred in direct gasification processes. The energy efficiency of direct and indirect gasification amounted to 62% and 53%, respectively. At the same time, the corresponding exergy efficiencies were 65% and 61%. The syngas of direct and indirect gasification processes is a starting point to produce energy, synthetic fuels, and chemicals; this study provides insights for designing and optimizing biomass gasification processes. [ABSTRACT FROM AUTHOR]

To meet all energy requirements by renewable energy (RE) sources, hydrogen is an effective energy transport and storage instrument. Because of being a highly innovative field in developing countries, there are high uncertainties with different subcomponents in the hydrogen energy (HE) field. In the literature, fuzzy set extensions are heavily preferred to model different types of uncertainties when making decisions in the energy field. As one of the most comprehensive ones, spherical fuzzy set (SFS) is used to model the uncertainties caused by refusal and inconsistency within some theoretical limitations. In this study, a novel fuzzy set (FS) extension called neutrosophic picture fuzzy set has been developed to obtain a more flexible and reliable modeling approach usable with the information having higher inconsistency, and suitable with the problems requiring precise calculations. As a popular decision-making (DM) techniques, TOPSIS methodology has been redesigned based on neutrosophic picture fuzzy set. By using the developed methodology, the available hydrogen production (HP) alternatives of Türkiye have been evaluated. Biomass gasification (BG) has been decided as the best hydrogen energy production method under the current conditions. The results have been compared with the results obtained by spherical fuzzy TOPSIS and it has been proved that more reliable results are obtained by the proposed method. [ABSTRACT FROM AUTHOR]

• Gasification of plastic in a large-scale fluidized bed with enriched air and steam. • Equivalence ratio crucially affects syngas composition. • Steam-to-oxygen ratio allows appropriate control of the reactor temperature. • A one-dimensional kinetic model predicts rather well syngas composition. Advanced thermochemical technologies for plastic waste valorization represent an interesting alternative to waste-to-energy options. They are particularly appealing for waste-to-hydrogen and waste-to-chemicals applications, with autothermal steam-oxygen gasification in fluidized bed reactors showing the greatest market potential. The study describes a series of experimental tests carried out on a large pilot-scale fluidized bed gasifier, using steam and O 2 -enriched air, with increasing fractions of oxygen. Different values of the main operating parameters are varied: equivalence ratio (0.22–0.25), steam-to-carbon ratio (0.7–1.13), and steam-to-oxygen ratio (up to 3.2). The fuel consists of real mixed plastic waste coming from separate collection of municipal solid wastes. The data obtained are used to investigate in depth the role of the main operating parameters and to improve and validate a recently developed one-dimensional kinetic model for waste gasification. The validation shows a good agreement between experimental data and model results, suggesting the reliability of the model to predict the reactor behavior under conditions of pure steam-oxygen gasification, relevant to many industrial applications. It has been found that the equivalence ratio is the parameter that most affects the syngas composition. At a constant equivalent ratio, the molar fraction of oxygen in the enriched air shows a limited influence on syngas composition while the steam is crucial in controlling the temperature along the reactor. Provided that the steam-to-carbon molar ratio is larger than 1.5, steam affects mainly the reactor temperature rather than the syngas composition, qualifying the steam-to-oxygen molar ratio as an instrumental parameter for smooth plant operation. [ABSTRACT FROM AUTHOR]

Biomass chemical looping hydrogen generation (CLH) process is a new thermochemical conversion technology which could realize the efficient conversion of biomass to hydrogen. In this study, the fuel reaction stage is decoupled into two stages, namely pyrolysis and gasification stages, but the AR in the general CLH process is removed. The oxygen carrier is used to couple the pyrolysis, gasification and hydrogen generation stages. As such, by coupling a tar chemical looping reforming (TCLR) process for pyrolysis tar, a biomass pyrolysis-gasification-hydrogen generation combined cycle system (namely, BPGH-TCLR) is constructed. Then, Aspen plus software is used to analyze the influence of process parameters including oxygen carrier/biomass ratio, gasification temperature, water steam/biomass ratio, reforming temperature, and explore the corresponding optimal parameter values. Also, mass, energy and exergy balances of the system are investigated whereas the system performance is evaluated. The calculation results show that 100 kg/h biomass as the BPGH-TCLR feed can produce 8.03 kg/h hydrogen and 35.51 kW net electric power with energy and exergy efficiencies of 59.35% and 49.24%, respectively, and a biomass conversion efficiency of 52.49%. Compared with the other processes for hydrogen production, this proposed BPGH-TCLR system shows better hydrogen generation efficiency as well as higher biomass conversion efficiency. • A novel system for hydrogen production from biomass is proposed and simulated. • The system consists of chemical looping process/tar chemical looping reforming. • The system has relatively higher energy utilization efficiency and exergy efficiency. • The system has higher hydrogen generation efficiency and biomass conversion rate. [ABSTRACT FROM AUTHOR]

Smouldering has recently been developed as a cost effective and energy efficient technology for challenging wastes. These systems are often used to eliminate environmental liabilities, and only minimal work has explored their use for generating useful by-products. This study addressed this research gap and demonstrated that applied smouldering systems can be tuned to favour hydrogen production. Calcium oxide and steam were added to the smouldering system, which completely treated woody biomass and coal tar, while producing hydrogen. The maximum hydrogen concentration achieved in the smouldering system was 33.7%, resulting in a net energy positive syngas. Results suggest that both heterogenous gasification and the water gas shift were key mechanisms behind hydrogen formation. These results indicate that smouldering systems can be used as a new method to sustainably produce hydrogen-rich syngas from challenging wastes. [Display omitted] • Experimental study produced up to 34% H 2 from smouldering combustion. • Experiments used different fuels, porous media, steam, and CaO amendments. • New methodology to drive net-energy-positive H 2 -rich syngas from smouldering. • Optimum steam/carbon ratio was found to be between 2 and 3 to maximize H 2 yield. • Heterogenous gasification and the water gas shift were key H 2 production mechanisms. [ABSTRACT FROM AUTHOR]

Hybrid thermochemical–biological processes have the potential to enhance the carbon and energy recovery from organic waste. This work aimed to assess the carbon and energy recovery potential of multifunctional processes to simultaneously sequestrate syngas and detoxify pyrolysis aqueous condensate (PAC) for short-chain carboxylates production. To evaluate relevant process parameters for mixed culture co-fermentation of syngas and PAC, two identical reactors were run under mesophilic (37 °C) and thermophilic (55 °C) conditions at increasing PAC loading rates. Both the mesophilic and the thermophilic process recovered at least 50% of the energy in syngas and PAC into short-chain carboxylates. During the mesophilic syngas and PAC co-fermentation, methanogenesis was completely inhibited while acetate, ethanol and butyrate were the primary metabolites. Over 90% of the amplicon sequencing variants based on 16S rRNA were assigned to Clostridium sensu stricto 12. During the thermophilic process, on the other hand, Symbiobacteriales, Syntrophaceticus, Thermoanaerobacterium, Methanothermobacter and Methanosarcina likely played crucial roles in aromatics degradation and methanogenesis, respectively, while Moorella thermoacetica and Methanothermobacter marburgensis were the predominant carboxydotrophs in the thermophilic process. High biomass concentrations were necessary to maintain stable process operations at high PAC loads. In a second-stage reactor, Aspergillus oryzae converted acetate, propionate and butyrate from the first stage into L-malate, confirming the successful detoxification of PAC below inhibitory levels. The highest L-malate yield was 0.26 ± 2.2 molL-malate/molcarboxylates recorded for effluent from the mesophilic process at a PAC load of 4% v/v. The results highlight the potential of multifunctional reactors where anaerobic mixed cultures perform simultaneously diverse process roles, such as carbon fixation, wastewater detoxification and carboxylates intermediate production. The recovered energy in the form of intermediate carboxylates allows for their use as substrates in subsequent fermentative stages. [ABSTRACT FROM AUTHOR]

The production of hydrogen from residual biomass represents a sustainable alternative to integrate the production of renewable hydrogen in coming years. This work shows the results obtained during an experimental campaign dedicated to analysing the performance of a downdraft gasifier of about 100 kW t fed with woody biomass and oxy-steam mixtures. With suitable oxygen-steam ratios it was possible to produce a syngas with a hydrogen content higher than 40%vol, with a cold gas efficiency of more than 80%. The experimental syngas composition is used as input of a numerical model, created in Aspen Plus® and dedicated to evaluating the performance of the plant section for the pure H 2 -production. The numerical analysis highlighted the possibility of obtaining approximately 5% by mass of hydrogen with respect to the biomass used, also evidencing how the correct use of thermal waste and residues makes the whole plant (gasifier plus hydrogenizer) independent on heat supply. • Woody biomass oxy-steam gasification has been analysed in a real-scale downdraft gasifier. • Oxy-steam gasification confirmed to be effective in increasing hydrogen yield in the syngas. • The optimum equivalence ratio and steam/biomass mass ratio have been determined. • A H 2 production plant has been conceived and analysed to exploit the produced syngas. • The study evidenced the possibility of obtaining a hydrogen/biomass mass ratio of 5%. [ABSTRACT FROM AUTHOR]

The main performance indicators of hydrogen energy production should be improved. However, improving these factors also increase the operational costs of the companies. Because of this issue, there is a need for a priority analysis so that it can be possible to focus on more important factors. Accordingly, the purpose of this study is to evaluate hydrogen production methods for global energy transition. In this process, a four-stage model has been proposed by getting evaluations from three different experts. Firstly, artificial intelligence-based decision-making can be implemented for expert prioritization. In the second stage, recommender system is conducted with collaborative filtering to complete the missing evaluations. Thirdly, selected criteria are weighted by using M-SWARA with QPFRS. Finally, method alternatives for hydrogen production are ranked via quantum picture fuzzy rough sets adopted VIKOR. The biggest contribution for doing this study is that artificial intelligence technique is integrated into the model and experts' importance coefficients are can be computed. Additionally, by using the collaborative filtering technique, empty evaluations can be filled scientifically. This contributes to the quality of the analysis process in many ways. Thanks to this technique, experts are given the opportunity not to answer questions they are not very sure about. The findings indicate that renewable energy expansion, energy efficiency and sustainable development are the most important criteria for global energy transition in hydrogen production. On the other side, the ranking results give information that thermal processes including steam methane reforming and biomass gasification is the most appropriate method alternatives for hydrogen production. Based on these analysis results, it is strongly recommended that research and development activities should be improved to increase the efficiency and effectiveness of the renewable energy projects. With the help of this issue, it can be much easier to increase the performance of hydrogen production process. • Hydrogen production methods are evaluated for global energy transition. • A four-stage model has been proposed. • Selected criteria are weighted by using M-SWARA. • Method alternatives for hydrogen production are ranked via VIKOR. • Renewable energy expansion is the most important criteria. [ABSTRACT FROM AUTHOR]

Biomass gasification process generates the residual tar, which in turn exerts some negative influence on biomass gasification system. To reduce this harmful influence, an evaluation of the tar properties during the biomass gasification was studied. The chemical composition and pyrolysis behavior of biomass tar were investigated. The complex chemical composition of the tar, which includes phenol derivatives, naphthalene derivatives, other macromolecular aromatic compounds, furans, and other compounds (carbon number from 7 to 14), was established by gas chromatography-mass spectrometry technique. Thermogravimetric analysis was performed with two heating rates (10°C/min and 20°C/min), and Coats-Redfern method was applied to assess the kinetic parameters, i.e., the activation energy (E) and pre-exponential factor (A) of tar thermochemical decomposition. The results showed that the main degradation of tar is a two-step process, including a volatilization step at lower temperatures (<105°C) and a pyrolysis step at higher temperatures (105°C-380°C). The application of the Coats-Redfern method revealed a variation trend of the activation energy during the decomposition of tar in a non-isothermal model. It shows that high temperature is more conducive to tar pyrolysis. By adjusting the temperature to control the generation and removal of tar, new approaches are provided for designing and optimizing biomass gasification systems. [ABSTRACT FROM AUTHOR]

It is crucial to increase the resilience of the global food production and distribution systems against the growing concerns relating to factors that could cause global catastrophic infrastructure losses, such as nuclear war or a worldwide pandemic. Currently, such an event would result in the global loss of industry, including the ability to drill and refine crude oil. In such an event, the existing above-ground reserves of diesel and gasoline are likely to still be intact but would only be able to power the production and transportation of food between 158 days and 481 days with 80% confidence, where the mean is 195 days at current rates. This paper investigates a novel group of interventions in relation to the scenario of providing food under these conditions. It was found that by using a plausible combination of wood gasification, increasing vehicle utilisation rate, and reducing food consumption, the stockpile duration could increase to between 382 days and 1501 days with 80% confidence, where the mean is 757 days. This is an improvement in mean duration by a factor of 3.9. It was discovered that diesel is the limiting fuel in all scenarios due to wood gas only being a partial replacement for diesel fuel and also because of the prevalence of diesel engines in both the agricultural and trucking industries. A sensitivity analysis was completed identifying that reducing food consumption to minimum levels was the most effective method to prolong diesel reserves. The other factors that benefited from extending fuel reserves in terms of their effectiveness are reducing the lag time before gasification devices are installed, increasing the rate at which gasification devices are installed, and increasing the agricultural equipment utilisation rate. [ABSTRACT FROM AUTHOR]

Adopting biomass energy as an alternative to fossil fuels for electricity production presents a viable strategy to address the prevailing energy deficits and environmental concerns, although it faces challenges related to suboptimal energy efficiency levels. This study introduces a novel combined cooling and power (CCP) system, incorporating an externally fired gas turbine (EFGT), steam Rankine cycle (SRC), absorption refrigeration cycle (ARC), and organic Rankine cycle (ORC), aimed at boosting the efficiency of biomass integrated gasification combined cycle systems. Through the development of mathematical models, this research evaluates the system's performance from both thermodynamic and exergoeconomic perspectives. Results show that the system could achieve the thermal efficiency, exergy efficiency, and levelized cost of exergy (LCOE) of 70.67%, 39.13%, and 11.67 USD/GJ, respectively. The analysis identifies the combustion chamber of the EFGT as the component with the highest rate of exergy destruction. Further analysis on parameters indicates that improvements in thermodynamic performance are achievable with increased air compressor pressure ratio and gas turbine inlet temperature, or reduced pinch point temperature difference, while the LCOE can be minimized through adjustments in these parameters. Optimized operation conditions demonstrate a potential 5.7% reduction in LCOE at the expense of a 2.5% decrease in exergy efficiency when compared to the baseline scenario. [ABSTRACT FROM AUTHOR]

This review presents the technical and operational performances of solar and biomass energy technologies viz photovoltaic thermal (PVT) and biomass gasification systems. This work aims to offer a reference and guidelines to the renewable energy‐related players, especially for those at the operational level and investors. This paper highlights the technical advantage of hybrid PVT with phase change material in terms of electrical and thermal efficiencies. While the operational performance of biomass gasification is thoroughly discussed via sensitivity analysis, the potential integration between solar and biomass gasification technologies is explored to complement and bolster the capabilities of both renewable systems within the power energy mix portfolio. Finally, few directions and significant takeaways considering the technical criteria are addressed for identifying efficient renewable energy generation. [ABSTRACT FROM AUTHOR]

This study investigated the behavior and syngas characteristics of oil palm biomass fluidized bed gasification (FBG) with alternative inlet air configurations. The air was supplied to the combustion zone of the FBG with tangential and updraft air inlet (TI and UI) modes. A mixed oil palm decanter cake was used as feedstock at 3 kg/h feed rate. The experiments were done at the equivalence ratios (ERs) from 0.1 to 1.0. The experimental results showed that the air supply mode and ER affected the temperature distribution inside the gasifier. Operation with TI mode had combustion initiated at the side, then propagated through the middle section, while in UI mode, the combustion reaction was at the center of the chamber. With TI mode, the temperature at combustion zone was around 600 °C. At ER 0.5, this zone covered the heights from 0.25 to 0.75 m. In UI mode, the highest temperature was near 800 °C, but combustion was prominent only in a zone near the bottom. The CFD simulations showed that the alternative inlet air configurations and the ER influenced flow patterns. CFD confirmed the swirling streamlines in TI mode, while UI mode showed a localized elevated temperature, particularly at 0.25 m height. Syngas composition analysis indicated that operation in TI mode at ER of 0.7 provided the larger combustion zone, leading to better syngas product in terms of CO (> 20%) and H2 (> 8%) components. This mode also provided the best 5.1 MJ/m3 energy content for syngas. The results of this study can provide useful guidelines for further investigations of FBG with tangential air inlet. [ABSTRACT FROM AUTHOR]

The present study models and examines a novel integrated process of fast pyrolysis of biomass using a system of solar type of heliostat and a system of energy storage by thermochemical method. This integrated model enables biomass pyrolysis to produce bio-oil, reducing the need of external heat and improving efficiency of pyrolysis. The discussion focuses on three: daily, weekly, and yearly, scenarios for storing solar energy. In addition, the evaluation includes assessing the solar fraction, size of the storage devices, power load of auxiliary heating device, and energyefficiency. The modeling and simulation tasks were conducted using Aspen Plus and Engineering Equation Solver. According to the findings, 0.680 kg per second pyro-oil can be generated from one kilogram per second biomass (hybrid poplar). Also 0.170 kg per second char and 0.160 kg per second gases could be yielded from one kilogram per second of the mentioned biomass. The integrated system yields a solar fraction of 0.850 as the resulting outcome. By utilizing the storage system, the thermal energy needed for pyrolysis system can be reduced from 36.49 to 3.929 MW. [ABSTRACT FROM AUTHOR]

The growing attention regarding the environmental challenges in the energy sectors pushes the industrial system toward the investigation of more sustainable and renewable energy sources to replace fossil ones. Among the promising alternatives, biomass is considered a valid source to convert the system and to reduce the fossil fraction of the national energy mixes, but its multiple potential uses need an environmental evaluation to understand the actual benefit when it is used as an energy resource. For this purpose, life cycle assessment (LCA) is applied to a wood biomass gasification system aimed to produce electricity and heat generated after the combustion of the produced syngas and the management of the biochar. The aim is to provide a quantitative comparison of (i) a baseline scenario where wood biomass is sourced from waste and (ii) a second scenario where wood biomass is drawn from dedicated cultivation. A further evaluation was finally applied to investigate the environmental implications associated with the biochar composition, assuming it was used on land. The proposed strategies resulted in an environmental credit for both the examined scenarios, but the outcomes showed a net preference for the baseline scenario, resulting in better environmental performances for all the examined categories with respect to the second one. It underlines the potentialities of using waste-sourced biomass. However, according to the Climate Change category, if on-site dedicated biomass cultivation is assumed for the second scenario, the baseline is considered preferable only if the biomass transportation distance is <600 km, which is estimated as a theoretical distance for scenarios to break even. Finally, biochar composition proved a particular concern for toxicity-related categories. This study highlights the importance of applying objective and standardized methodologies such as LCA to evaluate energy production systems based on alternative sources and to support decision-making toward achieving sustainability goals. [ABSTRACT FROM AUTHOR]

The Adrar region (Algeria) has a total of 397,800 date palm trees (Phoenix dactylifera L.). Due to annual palm cleaning, large quantities of lignocellulosic biomass are produced. Depending on the variety, an average of 65 kg of biowaste is obtained per palm tree. Since the value of this biowaste is underrated, most of the palms are burned outdoors, causing air and visual pollution. This work explores the gasification potential of lignocellulosic waste from date palms (Phoenix dactylifera L. Takarbouche variety) into useful energy. The technology investigated is air updraft fixed-bed gasification, thanks to an originally designed and built reactor, with the capability to process 1 kg of feedstock. Four types of palm waste—namely, palms, petioles, bunch, and bunch peduncles—are first characterized (bulk density, proximate analysis, fixed carbon, elemental composition, and calorific value) and then used as feedstock for two gasification tests each. The syngas produced for the four date palm wastes is combustible, with an outlet temperature between 200 and 400 °C. The operating temperature inside the gasifier varies according to the feature of the biomass cuts (from 174 °C for the peduncles to 557 °C for palms). The experimental setup is also equipped with a cyclone, allowing for the recovery of some of the tar produced during the tests. Finally, the results show that the residence time has a positive effect on the conversion rate of date palm waste, which can significantly increase it to values of around 95%. [ABSTRACT FROM AUTHOR]

• Biomethanol production from biomass gasification represents a circular economy approach for chemicals production. • Advanced configurations based on membranes for obtaining cleaning syngas from biomass are discussed. • The implementation of microchannels reaction technology is proposed to enhance the chemical engineering aspects of biomethanol production. • The production of biomethanol has an important socio-ecomnomic impact. The Intergovernmental Panel on Climate Change (IPCC) recognises the pivotal role of renewable energies in the future energy system and the achievement of the zero-emission target. The implementation of renewables should provide major opportunities and enable a more secure and decentralised energy supply system. Renewable fuels provide long-term solutions for the transport sector, particularly for applications where fuels with high energy density are required. In addition, it helps reducing the carbon footprint of these sectors in the long-term. Information on biomass characteristics feedstock is essential for scaling-up gasification from the laboratory to industrial-scale. This review deals with the transformation biogenic residues into a valuable bioenergy carrier like biomethanol as the liquid sunshine based on the combination of modified mature technologies such as gasification with other innovative solutions such as membranes and microchannel reactors. Tar abatement is a critical process in product gas upgrading since tars compromise downstream processes and equipment, for this, membrane technology for upgrading syngas quality is discussed in this paper. Microchannel reactor technology with the design of state-of-the-art multifunctional catalysts provides a path to develop decentralised biomethanol synthesis from biogenic residues. Finally, the development of a process chain for the production of (i) methanol as an intermediate energy carrier, (ii) electricity and (iii) heat for decentralised applications based on biomass feedstock flexible gasification, gas upgrading and methanol synthesis is analysed. [Display omitted] [ABSTRACT FROM AUTHOR]

The use of plasma processes in the production of biohydrogen opens up the possibility of replacing fossil fuels with an environmentally friendly energy source from biomass. The work examines the process of plasma processing of biomass (based on the example of sunflower husks), using an electrodeless discharge to produce highly productive synthesis gas with a high hydrogen content. The use of CFD modeling made it possible to determine the parameters of a steam plasma reactor for the gasification process. The operation of the reactor is based on the principle of gasification using steam-water plasma with oxygen. The use of plasma blast allows increasing the process temperature, the rate of physical and chemical transformations, the degree of conversion of raw materials, the residence time of gases in the reaction volume, the content of hydrogen and carbon monoxide in the synthesis gas, the thermal intensity of the reaction volume and specific productivity. It has been experimentally established that plasma power affects the energy balance of the entire gasification process, and also directly affects the temperature profile, synthesis gas composition, resin yield and stability of the gasification process. The influence of such parameters as the plasma energy to waste energy ratio (PER), equivalence ratio (ER) and steam to oxygen mass ratio (SOMR) on the gasification process was studied. It has been found that increasing PER raises the average temperature of the supplied steam-oxygen mixture and increases the heat input for gasification. A dual influence of ER on the gasification process has been noted: on the one hand, a higher ER provides more chemical heat during combustion, which has a beneficial effect on the synthesis gas output, and on the other hand, a higher ER provides an increase in the amount of combustion products in the reactor, which leads to reducing the amount of flammable gases. It has been determined that with an increase in SOMR from 2 to 2.5, the volume fraction of H2 in the synthesis gas increases, and CO2 decreases. Hydrogen obtained from biomass gasification processes is one of the promising methods for alternative hydrogen production from fossil fuels. [ABSTRACT FROM AUTHOR]

In order to realize low-carbon transformation in the energy industry and achieve the "double carbon" goal as scheduled, renewable energy represented by biomass has become increasingly attractive. Biomass gasification is a thermochemical treatment technology, which has seen rapid development in recent years. It is currently the most effective method for high-grade and efficient utilization of biomass energy. In this paper, the key units involved in the entrained flow gasification process, such as pulverization, transportation, and gasification were analyzed, and the feasibility of applying airflow bed technology to biomass gasification was demonstrated. Six typical agricultural and forestry biomasses were used as raw materials. Biomass entrained flow gasification simulation was carried out with the help of the Aspen Plus chemical process simulation software, and the coal and biomass co-gasification and biomass separate gasification processes were characterized. The carbon reduction effect of biomass gasification was analyzed. The results show that when a certain amount of biomass is added into coal, a good gasification performance is retained. With the increase of biomass blending ratio, the specific coal consumption gradually decreases, and the carbon reduction effect is apparent. Compared with traditional fixed bed and fluidized bed gasification, biomass entrained flow gasification has an advantageous calorific value of synthetic gas about 10 MJ/m³. It can be used as a surrogate for natural gas heating, which has economic value in achieving carbon reduction. This study is in line with the dual-carbon policy and also provides a reference for the efficient conversion and utilization of biomass. [ABSTRACT FROM AUTHOR]

The objective for hydrogen as a future energy carrier should be to produce it without emitting additional carbon dioxide into the atmosphere. A very effective process for hydrogen generation based on allotherm steam reforming using energy from biomass is developed and tested in a pilot facility. Excess chemical energy from the process is used to generate superheated steam (>1,200 °C). Steam is the gasification and oxidation agent, energy carrier for the process and supplier of hydrogen molecules, as it reacts with biochar at the bottom of the reactor. The produced synthesis gas has up to 61% of hydrogen. The handling of tars is much easier than in other systems due to the presence of excess steam. A demonstration facility has been designed with an overall efficiency of up to 70%, scaling up the pilot facility. Only waste biomass unsuitable for further usage is utilised, and the conversion rate of biomass to hydrogen is 10:1. [ABSTRACT FROM AUTHOR]

In light of growing concerns regarding greenhouse gas emissions and the increasingly severe impacts of climate change, the global situation demands immediate action to transition towards sustainable energy solutions. In this sense, hydrogen could play a fundamental role in the energy transition, offering a potential clean and versatile energy carrier. This paper reviews the recent results of Life Cycle Assessment studies of different hydrogen production pathways, which are trying to define the routes that can guarantee the least environmental burdens. Steam methane reforming was considered as the benchmark for Global Warming Potential, with an average emission of 11 kgCO2eq/kgH2. Hydrogen produced from water electrolysis powered by renewable energy (green H2) or nuclear energy (pink H2) showed the average lowest impacts, with mean values of 2.02 kgCO2eq/kgH2 and 0.41 kgCO2eq/kgH2, respectively. The use of grid electricity to power the electrolyzer (yellow H2) raised the mean carbon footprint up to 17.2 kgCO2eq/kgH2, with a peak of 41.4 kgCO2eq/kgH2 in the case of countries with low renewable energy production. Waste pyrolysis and/or gasification presented average emissions three times higher than steam methane reforming, while the recourse to residual biomass and biowaste significantly lowered greenhouse gas emissions. The acidification potential presents comparable results for all the technologies studied, except for biomass gasification which showed significantly higher and more scattered values. Regarding the abiotic depletion potential (mineral), the main issue is the lack of an established recycling strategy, especially for electrolysis technologies that hamper the inclusion of the End of Life stage in LCA computation. Whenever data were available, hotspots for each hydrogen production process were identified. [ABSTRACT FROM AUTHOR]

The utilization of biomass for multi-generation systems is garnering significant interest due to its potential in conserving primary energy and mitigating greenhouse gas emissions. However, enhancing its energy efficiency remains a critical challenge. This study introduces an innovative cogeneration system that combines biomass gasification with an externally fired gas turbine, organic Rankine cycle, and absorption refrigeration cycle. It undergoes thorough thermodynamic and exergoeconomic evaluations, with a dual-objective optimization conducted to identify the optimal operational conditions that achieve the highest exergy efficiency while minimizing product cost. The findings reveal that, in the base case, the thermal efficiency, exergy efficiency, and sum unit cost of the product (SUCP) of the system are 66.36%, 32.04%, and 8.71 USD/GJ, respectively. A parametric study illustrates that elevating the air compressor pressure ratio or the temperature difference at the cold end enhances thermal efficiency but reduces exergy efficiency. Additionally, the lowest unit cost of the product is attainable by optimizing the gas turbine inlet temperature. The performance of the system shows negligible sensitivity to the turbine inlet pressure of a bottoming organic Rankine cycle. Finally, optimization demonstrates a 9.7% increase in exergy efficiency and a 1.8% rise in the SUCP compared to the baseline scenario. The study suggests integrating with other energy sources for diversified product outputs and conducting environmental analyses in future research. [ABSTRACT FROM AUTHOR]

The treatment of wastewater worldwide generates substantial quantities of sewage sludge (SS), prompting concerns about its environmental impact. Various approaches have been explored for SS reuse, with energy production emerging as a viable solution. This study focuses on harnessing energy from domestic wastewater treatment (WWT) sewage sludge through plasma gasification. Effective syngas production hinges on precise equipment design which, in turn, depends on the detailed feedstock used for characterization. Key components of plasma gasification include the plasma torch, reactor, heat exchanger, scrubber, and cyclone, enabling the generation of inert slag for landfill disposal and to ensure clean syngas. Designing these components entails considerations of sludge composition, calorific power, thermal conductivity, ash diameter, and fusibility properties, among other parameters. Accordingly, this work entails the development of an experimental setup for the plasma gasification of sewage sludge, taking into account a comprehensive sludge characterization. The experimental findings reveal that domestic WWT sewage sludge with 40% humidity exhibits a low thermal conductivity of approximately 0.392 W/mK and a calorific value of LHV = 20.78 MJ/kg. Also, the relatively low ash content (17%) renders this raw material advantageous for plasma gasification processes. The integration of a detailed sludge characterization into the equipment design lays the foundation for efficient syngas production. This study aims to contribute to advancing sustainable waste-to-energy technologies, namely plasma gasification, by leveraging sewage sludge as a valuable resource for syngas production. [ABSTRACT FROM AUTHOR]

Understanding the complex dynamics and spatial distribution of rising bubbles in fluidized bed gasifiers is crucial for designing, optimizing, and scaling up of the reactor. However, existing studies on bubble dynamics mainly focused on cold flow investigations, failing to capture the behavior of bubbles under the influence of chemical reactions and intricate coupling of heat transfer. Therefore, a reactive Lagrangian model is established to explore intricate bubble behaviors during biomass air gasification. The model is well validated with experiment, and the impact of operating parameters including bed temperature and equivalence ratio (ER) on the bubble behaviors is studied. The growth, coalescence, break, and eruption of rising bubbles are studied. A lower ER is recommended for better gasification performance. With an increase in the ER from 0.12 to 0.3, both the lower heating value and combustible gas concentration experienced a decrease of approximately 38.5% and 38.3%, respectively. The lateral feeding of biomass leads to asymmetrical distribution of bed temperature and bubble properties. Near the biomass inlet, a larger bubble aspect ratio is observed, possibly attributed to the hindrance in the lateral bubble growth due to the lateral biomass feeding. The bubble coordinate number is introduced to characterize the degree of bubble distribution density in a specific region. It is found that increasing the operating temperature results in a reduction in the density and an increase in the volume of bubbles at the bottom, resulting in a denser distribution of bubbles in this region. Although this concentrated bubble distribution may impact local heat and mass transfer, the differences in bubble distribution under temperature dominance gradually decrease along the reactor height. The impact of the operating conditions on the thermal properties and spatial distribution of bubbles obtained in this work can provide valuable guidance for practical gasification operations. [ABSTRACT FROM AUTHOR]