Gasification Agent Research Articles

Optimizing Syngas Production from Municipal Solid Waste Gasification: A Dual Reactor Fluidized Bed Study with Steam and CO2 as Gasification Agents

The escalating production of municipal solid waste (MSW) poses significant environmental and health hazards due to air, water, and soil pollution. Utilizing MSW as an energy source through gasification offers a promising solution to mitigate these impacts. This study investigates the gasification of MSW using a Dual Reactor Fluidized Bed, a thermal technology that converts solid substrates into usable gaseous fuels. The primary objective is to optimize the quality of the produced syngas by employing specific gasification agents, namely steam and CO2, and their mixtures. The research examines the effect of these agents on H2/CO ratios across a wide range of low operating temperatures, from 400°C to 700°C, using silica sand as a heat conduction medium between interconnected combustion and gasification reactors. The results demonstrate that the composition of syngas is strongly influenced by gasification temperature fluctuations. Increasing temperatures from 400°C to 700°C correlate with higher concentrations of CO and H2 in the syngas. The use of steam as a gasification agent yields H2 concentrations up to 25%, while transitioning from steam to CO2 leads to a substantial increase in CO composition, reaching 22.73%. Further analysis reveals that the H2/CO ratio decreases from 1,78 with steam and 0.64 with CO2, highlighting the crucial role of gasification agents in syngas quality. This study underscores the potential for optimizing syngas production from MSW by manipulating gasification temperatures and transitioning between different agents (steam, CO2, and their mixtures), resulting in an overall increase in the calorific value of the produced gas. These findings emphasize the opportunity to transform substantial environmental challenges associated with MSW into promising sustainable energy solutions through advanced gasification technologies.

CO2 Conversion by Oxygen-Enriched Gasification of Wood Chips

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.

Optimization of biomass-fueled multigeneration system using SOFC for electricity, hydrogen, and freshwater production

The rapid depletion of fossil fuel resources and their detrimental impact on the environment necessitates the exploration of renewable energy alternatives. Biomass stands out as a reliable renewable source, especially in multigeneration systems. This study suggests a biomass-driven multigeneration configuration for the production of electricity, heating, hydrogen, and freshwater. The configuration is evaluated from thermodynamic and economic perspectives, utilizing an Artificial Neural Network to predict key outcomes. The system optimization process integrates Machine Learning with decision-making methods to achieve optimal conditions. The findings highlight that an anode-cathode gas recycling design is the most effective configuration for the Solid Oxide Fuel Cell unit, achieving a cycle efficiency of 67.68% and a product cost of $11.41/GJ. Municipal Solid Waste biomass and CO2 were identified as the most efficient fuel and gasification agents, respectively. The evaluations also determined that the integration of the multi-objective grey wolf optimizer and the CatBoost method is the most reliable machine learning model for optimization. Furthermore, by combining the Multi-Objective Harris Hawks Optimization algorithm with TOPSIS, LINMAP, and Fuzzy decision-making approaches, the system achieves optimal performance across multiple scenarios. In one scenario, the system reached an exergy efficiency of 67.68% and a hydrogen production rate of 22.34 kg/h. The optimum recycling ratios for the anode and cathode were determined to be 0.16 and 0.38, respectively. The study demonstrates the feasibility of the proposed configuration, offering significant potential for sustainable and cost-effective energy generation.

Low-emission hydrogen production from gasification of Australian coals – Process simulation and technoeconomic assessment

Although renewable energy-based technologies such as water electrolysis and biomass gasification for hydrogen production are cleaner than fossil energy-based routes, there are still prevailing challenges associated with the high cost and operational challenges in the scale-up of those technologies in the short term. Considering the abundance of coal as a current primary source of energy in Australia, the use of coal to produce hydrogen is not only in line with Australia's resource endowment but is also expected to become a supplement to the other hydrogen production pathways during the global energy transition period. This paper presents a comprehensive techno-economic assessment of low-emission hydrogen production from Australian coal gasification integrated with carbon capture and storage (CCS). The study explores four cases of hydrogen production, comparing Australian brown coal (Victorian brown coal) and black coal (Queensland black coal) gasification. Variations in gasifiers, gasification agents, and associated operating conditions contribute to differences in energy efficiency, costs, and CO2 emissions among the cases. The findings reveal a levelized cost of hydrogen from coal gasification ranging between A$4.12–4.90 per kg of hydrogen. Notably, entrained flow gasification of Victorian brown coal in a mixture of oxygen and steam environment demonstrates advantages under the current market conditions. However, less mature technologies like dual fluidized bed gasifiers could emerge as viable alternatives if deployed on a commercial scale. The study also addresses direct carbon emissions from the process, indicating a CO2 emission intensity range of 16.3–20.9 kg CO2/kg H2 without CCS and 0.1–1.1 kg CO2/kg H2 with CCS for the four cases. These insights contribute valuable information for decision-making in the pursuit of sustainable and economically feasible hydrogen production methods during the ongoing energy transition.

Bench-Scale Gasification of Olive Cake in a Bubbling Fluidized Bed Reactor

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.

Thermodynamic equilibrium modeling of biomass gasification: Effects of operating conditions on gasifier performance

Biomass has remarkable potential to reduce harmful emissions and ensure stable and sustainable energy production. In this paper, various parameters such as operating temperature, type of gasifying agent, air–fuel ratio and steam-fuel ratio are investigated on the qualitative characteristics of the syngas obtained from biomass gasification. The qualitative indicators considered were the percentage of combustible components under the energy aspect and the percentage of undesirable components under the environmental aspect. The composition of the syngas was determined for a temperature range of 500–1000 °C as an equilibrium composition using the Gibbs free energy minimisation method. The results showed that increasing the gasification temperature above 900 °C had a positive effect on the energy and environmental properties of the syngas. Air and water vapour were selected as possible gasifying agents. The results showed that water vapour was significantly more favourable than air as a gasifying agent in terms of syngas quality. In the best case, the H2 yield for gasification with air is 35 %vol, while this value reaches 65 %vol for gasification with steam. In addition to the type, the ratio of the gasifying agent to the amount of fuel was also analysed. The analysis showed that it was more favourable to carry out the gasification process at lower air-to-fuel and steam-to-fuel ratios, which is consistent with the work of other authors.

Experimental Study of Textile Waste Gasification with Different Gasifying Agents.

En este trabajo se estudia la gasificación de residuos textiles empleando distintos agentes gasificantes a una temperatura de 900 °C, evaluando la composición volumétrica del gas de síntesis obtenido, así como los requerimientos energéticos y el poder calorífico del gas obtenido en cada caso.

Simulations on coal water slurry gasification by molecular dynamics method with ReaxFF.

Coal water slurry (CWS) is a new type of liquid coal product with low pollution, which is mainly used in the chemical industry to produce syngas (CO + H2). It is of great significance to study the microscopic mechanism of CWS gasification reaction for improving the efficiency of coal gasification. In this paper, the method of molecular dynamics based on reaction force fields (ReaxFF-MD) is used to study the gasification process of CWS/O2 system at different temperatures. The results show that, in the range of 1600-2400 K, the macromolecular network structure of lignite is decomposed into a large number of small molecular structures and a small number of light tar free radical fragments, and the types and quantities of reaction products increased rapidly. At 2400-4000 K, the free radical fragments of light tar are further decomposed and reacted with gasification agents, but the types and quantities of reaction products have little change. At 3600 K, a full gasification reaction occurred in the system, and the content of syngas is the highest. The model was established and optimized by Materials Studio (MS) software. Based on ReaxFF-MD method, Lammps software was used to simulate the gasification process of CWS/O2 system, and the reaction force field files containing C, H, O, N, and S element were used. By calculating the activation energy of gasification reaction, the rationality of the model and calculation method was illustrated. The post-processing of the results was implemented using OVITO, ChemDraw software, and self-programmed Python scripts.

Insights into bacterial diversity in industrial post-processing water from underground coal gasification (UCG) process

This study represents the first culture-independent profiling of microbial diversity in post-processing wastewater from underground coal gasification (UCG) processes. Three types of post-processing wastewater, named W1, W2 and W3, were obtained from three UCG processes involving two types of coal and two gasification agents, namely oxygen-enriched air and oxygen. Very high concentrations of BTEX (benzene, toluene, ethylbenzene, xylene), polyaromatic hydrocarbons (PAHs), and phenol were detected in the wastewater, classifying it into the fifth toxicity class, indicating very high acute toxicity. The values for the Shannon (H), Ace and Chao1 indices in W2 were the lowest compared to their values in W1 and W3. The dominate phyla were Proteobacteria, contributing 84.64% and 77.92% in W1 and W3, respectively, while Firmicutes dominated in W2 with a contribution of 66.85%. At the class level, Gammaproteobacteria and Alphaproteobacteria were predominant in W1 and W3, while Bacilli and Actinobacteria were predominant in W2. Among Bacilli, the Paenibacillus and Bacillus genera were the most numerous. Our results suggest that the main differentiating factor of the bacterial structure and diversity in the wastewater could be the gasification agent. These findings provide new insights into the shifting patterns of dominant bacteria in post-processing wastewater and illustrate the spread of bacteria in industrial contaminated wastewater.

Syngas composition analysis for waste to methanol production: Techno-economic assessment using machine learning and Aspen plus

The yield of methanol is heavily influenced by the composition of the syngas which varies from waste type and gasification conditions. This study uniquely explores machine learning (ML) and artificial neural network (ANN) algorithms with shapley additive values (SHAP) analysis to predict syngas compositions and interpret the complexities of waste gasification. Aspen Plus is then utilized to investigate the impact of syngas compositions on the economics of methanol production. Among the different ML models, gradient boosting regression achieved remarkable accuracy in predicting carbon monoxide and carbon dioxide, while ANN excelled in predicting nitrogen and hydrogen based on the coefficient of determination (>0.95). The feature importance analysis demonstrated the gasification agent type as the most important feature. Steam gasification of waste sawdust, straw, and wood chips showed the highest methanol yield. Economic analysis indicated the lowest levelized cost of methanol (LCMeOH) to be 1195.79 USD/MT which further decreased to 933.97 USD/MT upon hydrogen addition. Uncertainty analysis using Monte Carlo method showed the possible minimum LCMeOH to be 254.05 USD/MT. This study provides a comprehensive picture of the economic viability of waste-to-methanol production and provides an important reference for stakeholders on a global scale to quickly assess the feasibility of waste-to-energy projects.

Optimization of a syngas-fueled SOFC-based multigeneration system: Enhanced performance with biomass and gasification agent selection

In light of abundant sources of biomass feedstocks and regarding the higher performance in syngas-fueled-based SOFC systems, this work proposes a novel multigeneration system based on the combination of syngas-fuel SOFC, Kalina cycle, humidification-dehumidification desalination unit, and proton exchange membrane electrolyzer. This system is designed for simultaneous production of power, heating, freshwater, and hydrogen. Comprehensive energy, exergy, exergoeconomic, environmental, and economic analyses have been conducted to evaluate its performance. The optimum input biomasses, gasification agents, and operating conditions were determined using a coupled approach of an artificial neural network, multi-objective Particle Swarm Optimization algorithm, and the Linear Programming Technique for Multidimensional Analysis of Preference decision-making method. Under base input conditions, the energy and exergy efficiencies of the proposed system were found to be 53.66 % and 38.2 %, respectively. The system also demonstrated the capability to produce 0.1633 kg/s of freshwater and generate a net power output of 377.6 kW. The results indicate that using oxygen-enriched air in the gasification process notably enhances efficiency while reducing emissions. Straw and CO₂ were identified as the optimal feedstock and gasification agent, yielding an exergy efficiency of 42.71 % and a total product cost of 6.29 $/GJ at the optimum point. Moreover, with a selling price of $0.20/kWh for electricity and a fuel cost of $6/GJ, the system can achieve total revenue of approximately $1.65 million with a payback period of 4.01 years. These findings underscore the proposed plant's profitability under specific pricing conditions, making it an attractive investment opportunity.

Gasification of Liquid Hydrocarbon Waste by the Ultra-Superheated Mixture of Steam and Carbon Dioxide: A Thermodynamic Study

The thermodynamic modeling of waste oil (WO) gasification by a high-temperature gasification agent (GA) composed of an ultra-superheated H2O/CO2 mixture is carried out. The GA is assumed to be obtained by the gaseous detonation of fuel–oxidizer–diluent mixture in a pulsed detonation gun (PDG). N-hexadecane is used as a WO surrogate. Methane or the produced syngas (generally a mixture of H2, CO, CH4, CO2, etc.) is used as fuel for the PDG. Oxygen, air, or oxygen-enriched air are used as oxidizers for the PDG. Low-temperature steam is used as a diluent gas. The gasification process is assumed to proceed in a flow-through gasifier at atmospheric pressure. It is shown that the use of the detonation products of the stoichiometric methane–oxygen and methane–air mixtures theoretically leads to the complete conversion of WO into a syngas consisting exclusively of H2 and CO, or into energy gas with high contents of CH4 and C2-C3 hydrocarbons and an LHV of 36.7 (fuel–oxygen mixture) and 13.6 MJ/kg (fuel–air mixture). The use of the detonation products of the stoichiometric mixture of the produced syngas with oxygen or with oxygen-enriched air also allows theoretically achieving the complete conversion of WO into syngas consisting exclusively of H2 and CO. About 33% of the produced syngas mixed with oxygen can be theoretically used for PDG self-feeding, thus making the gasification technology very attractive and cost-effective. To self-feed the PDG with the mixture of the produced syngas with air, it is necessary to increase the backpressure in the gasifier and/or enrich the air with oxygen. The addition of low-temperature steam to the fuel–oxygen mixture in the PDG allows controlling the H2/CO ratio in the produced syngas from 1.3 to 3.4.

Unlocking waste potential: A neural network approach to forecasting sustainable acetaldehyde production from ethanol upcycling in biomass waste gasification

The upcycling of biomass waste gasification process for ethanol and acetaldehyde production has been augmented by integrating secondary and tertiary processes. A simulation model using Aspen Plus, developed from experimental investigations to assess the viability of this proposed system. Furthermore, this model has been utilized to create an Artificial Neural Network (ANN) prediction model. Process sustainability analysis demonstrated an energy efficiency of 64 % while economic viability up to 80 % process efficiency with an Internal Rate of Return (IRR) of 6 % and a payback period of 2107 days. An optimization strategy and an artificial neural network (ANN)-based predictive model have been developed. Optimization results revealed that a gasifier temperature of around 600 °C, a gasifying agent ratio of 2.0, and an acetaldehyde reactor temperature of 300 °C yield better process outcomes and revenue. The ANN model exhibited robust performance with coefficient of determination (R2) values ranging from 0.92 to 0.98 for acetaldehyde, hydrogen, and total revenue. Mean absolute error (MAE) and mean absolute percentage error (MAPE) fell within the range of 0.03–0.1 and 0.1–1.12 %, respectively. Consequently, given the favorable sustainability and predictive model performance, this study can be used for similar endeavors.

Digestate and woodchips gasification: A comparison of different gasifying agents

Digestate is the secondary product of the fermentation process in biogas plants. The use of digestate as a fertilizer is very common. However, this is more and more limited nowadays and therefore alternative uses for digestate are sought. The research described in this article maps the possibilities of using digestate from the wet fermentation process for the syngas generation. This work is focuses on the gasification of the digestate with spruce chips mixtures. The mixtures were prepared with a proportion of 0, 25, 50, 75 and 100% of the digestate. The experiments were carried out on a semi-operational fluidized bed gasifier at atmospheric pressure. The working temperature of the fluidized bed was 810 °C; the gasification was autothermal. The gasification was carried out with three types of gasification agents, i.e. air, air-steam, and oxygen-steam for each fuel mixture. The aim of the research was to assess the effect of the digestate with wood chips on the qualitative and quantitative properties of the syngas. The digestate can be characterized as a secondary energy source reducing the consumption of primary energy sources. The produced syngas is of high quality and the digestate can become a very desirable fuel for the syngas production.

Numerical Study on Combustion Characteristics of Biogas Cocombustion in a 300MW Coal-Fired Boiler Furnace.

To further explore cocombustion technology with biogas and coal, a series of numerical simulations have been carried out to analyze the effects of the cocombustion ratio ξ, height of biogas nozzle HGN, and tilt angle of burner θBN on combustion characteristics in a 300 MW four-corner tangential boiler furnace. Three types of biogas are gasified from straw, sawdust, and raw wood when air serves as the gasification agent. The velocity field, temperature field, and NO emissions have been comprehensively analyzed when the values of ξ, HGN, and θBN range, respectively, from 0.02 to 0.12, from 17.3 to 20.3 m, and from -15° to +15°. Results showed that the NO concentration at the furnace outlet monotonously decreased with ξ. The injection of biogas reduces both the peak temperature of the entire boiler furnace and the NO concentration at the furnace outlet. The NO emission concentration decreases with the increased ξ value for all types of biogases. The cocombustion with sawdust biogas indicates the least NO emission at a fixed cocombustion ratio. Furthermore, reducing the furnace height at HGN = 17.3 m or titling down the burner at θBN = -15° contributed to a greater NO concentration at the furnace outlet.

Cost-effectiveness and economic growth potential evaluation of olive pomace gasification process to sustainable fuel: Comparison study of different gasifying agent

This research addresses the growing global demand for sustainable and renewable energy solutions, focusing on biomass gasification (BG) as a promising avenue. Olive pomace is explored as a primary feedstock, assessing its potential as a plentiful and renewable energy source. The study aims to bridge existing gaps in the literature, particularly in the simultaneous and comparative examination of CO2, steam, and air as traditional gasifying agents. Utilizing Aspen Plus, a validated simulation tool, the research models the gasification process (GP) while considering key parameters such as gasifying agent, feed composition, and temperature. Through meticulous simulation and validation against experimental data, the goal is to develop a robust model tailored for gasification. A thorough sensitivity analysis evaluates critical parameters' impact on exergy efficiency, levelized cost of hydrogen (LCOH), and molar flow of hydrogen (H2). Parameters include temperature variations (600°C to 1000°C), equivalence ratio (ER) for the air agent (0.15–0.3), C/CO2 ratio for the CO2 agent (1–2.5), and SBR for the steam agent (0.5–2). The aim is to provide a nuanced understanding of these parameters and their influence on system performance, offering valuable insights for process optimization. The response surface methodology is employed to optimize critical parameters for distinct gasification agents, aiming to identify the most economically efficient agent. The study's findings are crucial for enhancing BG efficiency and developing sustainable energy systems. An economic evaluation underscores the cost-effectiveness of the GP, emphasizing its potential for economic growth in the renewable energy sector and long-term savings. In the concluding phase, optimization of the GP aimed at minimizing LCOH and maximizing molar flow of H2 and exergy efficiency was conducted. Upon scrutinizing the optimization results, a compelling conclusion arose: The steam agent emerged as the most suitable, with 48% exergy efficiency, 1.77 €/kg LCOH, and an optimal temperature of 884°C. Notably, steam showcased remarkable exergy efficiency, even when subjected to lower temperatures, positioning it as a superior choice.

A novel gas injection method with swirl flow in underground gasification for improving gas production and controlling pollution yields

Underground coal gasification (UCG) is a promising technology, which can convert deep coal seams into high calorific value gas products through in-situ controllable combustion, for the traditional coal mining technology. However, the structure of raw coal is dense, and it is difficult for the injected gasification agent to penetrate from the coal surface to the inside of coal in the gasification channel, which leads to worse gasification performance. Different from conventional straight flow injection, swirl flow injection is proposed to improve the effective contact between the gas and the coal surface to enhance the gasification reaction efficiency. In this work, various types of novel swirl nozzles were independently designed. The characteristics of gas production, temperature distribution and tar pollutant are studied with different swirl angles. As the swirl number increases from 0 to 1.41, there is a significant enhancement in the residence time of oxygen in the axial direction and a reduction of the mass transfer between oxygen and the coal wall in the radial direction. As the oxygen flow rate increases from 0.5 to 2 L/min, swirl flow injection exhibits stronger gasification performance than traditional straight flow injection, such as maximum gas calorific value and tar generation control capability.

Thermo-Mechano-Chemical Processing of Printed Circuit Boards for Organic Fraction Removal

Printed circuit boards (PCBs) are the main components of e-waste. In order to reduce the negative impact of waste PCBs on human health and the environment, they must be properly disposed of. A new method is demonstrated for recycling waste PCBs. It is referred to as the high-temperature thermo-mechano-chemical gasification (TMCG) of PCBs by the detonation-born gasification agent (GA), which is a blend of H2O and CO2 heated to a temperature above 2000 °C. The GA is produced in a pulsed detonation gun (PDG) operating on a near-stoichiometric methane–oxygen mixture. The PDG operates in a pulsed mode producing pulsed supersonic jets of GA and pulsed shock waves possessing a huge destructive power. When the PDG is attached to a compact flow reactor filled with waste PCBs, the PCBs are subject to the intense thermo-mechano-chemical action of both strong shock waves and high-temperature supersonic jets of GA in powerful vortical structures established in the flow reactor. The shock waves grind waste PCBs into fine particles, which undergo repeated involvement and gasification in the high-temperature vortical structures of the GA. Demonstration experiments show full (above 98%) gasification of the 1 kg batch of organic matter in a setup operation time of less than 350 s. The gaseous products of PCB gasification are mainly composed of CO2, CO, H2, N2, and CH4, with the share of flammable gas components reaching about 45 vol%. The solid residues appear in the form of fine powder with visible metal inclusions of different sizes. All particles in the powder freed from the visible metal inclusions possess a size less than 300–400 μm, including a large fraction of sizes less than 100 μm. The powder contains Sn, Pb, Cu, Ni, Fe, In, Cd, Zn, Ca, Si, Al, Ti, Ni, and Cl. Among these substances, Sn (10–20 wt%), Pb (5–10 wt%), and Cu (up to 1.5 wt%) are detected in the maximum amounts. In the powder submitted for analysis, precious elements Ag, Au, and Pt are not detected. Some solid mass (about 20 wt% of the processed PCBs) is removed from the flow reactor with the escaping gas and is partly (about 10 wt%) trapped by the cyclones in the exhaust cleaning system. Metal inclusions of all visible sizes accumulate only in the flow reactor and are not detected in powder samples extracted from the cyclones. The gasification degree of the solid residues extracted from the cyclones ranges from 76 to 91 wt%, i.e., they are gasified only partly. This problem will be eliminated in future work.

Techno-economic analysis and eco-efficiency indicators of a biomass-solar hybrid renewable energy system for João Pinheiro City

The study aims to rapidly scale up Hybrid Renewable Energy System (HRES) specifically emphasizing bioenergy generation for isolated rural communities. It aims to identify the most profitable and efficient configuration for HRES biomass-solar in João Pinheiro, taking advantage of local eucalyptus production to reduce costs associated with the transport of biomass waste, considering energy, economic and ecological indicators. Eucalyptus waste was chosen as the source of biomass as fuel, the Downdraft gasifier with air as the gasification agent, and monocrystalline silicon technology was selected for photovoltaic modules. Two case study scenarios were proposed based on global efficiency calculations. The techno-economic analysis was applied based on the First Law of Thermodynamics and the Levelized Cost of Electricity (LCOE) method. Case 2 showed the overall energy efficiency of 17.43% and LCOE 0.034 US$/kWh more suitable for HRES solar-biomass technology. Additionally, the eco-efficiency indicator indicator based on the calculated Net Present Value and ecological efficiency indicator, allowed evaluation of the relationship between added value and the environmental impacts associated with the studied configurations, with case 2 presenting 9.28e−05 kgCO2/US$ as best result. The conclusions show that the techno-economic analysis applied to the HRES syngas-solar, along with the eco-efficiency indicator, presents the viability of decentralized bioenergy supply, particularly in isolated rural communities. This innovative approach encourages sustainable measures to meet energy needs in isolated regions with climatic, environmental and biomass supply conditions like those of João Pinheiro.

Pyrolysis and catalytic reforming of disposable plastic waste for syngas production with adjustable H2/CO ratio

The gasification technology has shown great potential to upcycle plastic waste for clean and high-value fuel. Gasification of disposable plastic masks was investigated in a two-stage pyrolysis-catalytic reforming system, aiming at producing the syngas with flexible H2 to CO ratio which can be tuned for various downstream applications without further purification and adjustment. To maximize the syngas yield and minimize the carbon deposition, different gasifying agents in the staged catalytic process was explored. The results showed that CO2 significantly promoted syngas production mainly by increasing CO yield. However, H2-rich syngas was obtained via using steam as the gasifying agent. Competitive and synergistic relationships between CO2 and H2O agent at co-feeding process were further revealed. CO2 facilitated the reforming of H2O at low dose of steam while exhibiting a main competition with adequate steam except for synergy at 5 mL/min CO2 flow rate. An optimum H2-rich syngas yield of 135.59 mmol/gplastic with H2/CO ratio of 2 was obtained at co-feeding reactants. Therefore, the co-feeding of H2O and CO2 could show positive effect for both coke removal and syngas quality regulation. Results found in this work increased the overall operational flexibility and economy of pyrolysis and catalytic reforming of plastic waste.