Efficient Gas Research Articles

Influencing Factors and Purification Performance of a Negative Ion Air Purifier for Indoor Ammonia Gas Removal

The negative ion air purifier (NIAP) has been used for capturing particulate matter. Nevertheless, the knowledge on its effectiveness in removing other air pollutants such as ammonia gas remains limited. In this study, the effect of an NIAP for indoor ammonia gas removal was evaluated through a series of experimental studies. The applicability and different influencing, operating, and environmental factors on the ammonia gas removal performance were firstly investigated by conducting a series of experiments. Then, in order to understand the performance of the NIAP and the spatial distribution of ammonia gas and other by-products, indoor field measurements of ammonia gas, ozone, and negative ion concentrations in a real bathroom were performed for different cases with the NIAP turned on and off. The results indicated that negative ions were effective in reducing ammonia gas concentration. The operating and environmental factors including upstream wind speed, degree of operating voltage, and initial ammonia gas concentration have great influences on the ammonia gas removal efficiency of the NIAP. The highest removal efficiency can reach to 95.8%, when the upstream wind speed was 0.8 m/s and the degree of operating voltage was at gear 3 (3.0 kV). The purification efficiency of ammonia gas for the NIAP could reach up to 80%.

First-Principles Calculations of Group-IV Carbide Quantum Dots and Single-Layer Heterojunctions with Optical Activity and Short-Wave Infrared Emission for Efficient Gas Sensing

First-Principles Calculations of Group-IV Carbide Quantum Dots and Single-Layer Heterojunctions with Optical Activity and Short-Wave Infrared Emission for Efficient Gas Sensing

Continuous photo-oxidation of methane to methanol at an atomically tailored reticular gas-solid interface

Photo-oxidation of methane (CH4) using hydrogen peroxide (H2O2) synthesized in situ from air and water under sunlight offers an attractive route for producing green methanol while storing intermittent solar energy. However, in commonly used aqueous-phase systems, photocatalysis efficiency is severely limited due to the ultralow availability of CH4 gas and H2O2 intermediate at the flooded interface. Here, we report an atomically modified metal-organic framework (MOF) membrane nanoreactor that promotes direct CH4 photo-oxidation to methanol at the gas-solid interface in a reticular open framework. We show that the domino synergy between colocalized single-atom palladium and iron on MOF nodes enables efficient generation and in situ utilization of H2O2 in the absence of liquid water, thus circumventing H2O2 dilution. Meanwhile, the “breathable” MOF membrane, optimized by solar-driven interfacial water management, provides high-flux channels to facilitate efficient gas diffusion and rapid methanol desorption and transfer. As a result, we demonstrate over 210 hours of continuous photosynthesis of 0.25 M methanol with unity selectivity, achieving an exceptional methanol productivity of 14.4 millimoles per gram of catalyst per hour.

Hammerhead Shark‐Inspired Microvillus‐Structured Ionic Elastomers for Wet Gas Sensing Based on Solvated Ion Transport

AbstractWater molecules are ubiquitous disruptors of conventional gas sensing materials, often leading to diminished sensing performance in materials that are reliant on electronic signal transmission. This creates the pressing need for efficient gas sensing materials with anti‐humidity interference properties. Here, a hammerhead shark‐inspired microvillus‐structured ionic elastomer based on ionic signal transmission in nanoconfined space is constructed by incorporating ionic liquids into a polymer matrix. The ionic elastomers with optimized microvillus structure demonstrated a 1.68‐fold higher response than that of the flat ones, short response time (9 s) toward 30 ppm triethylamine (TEA), excellent selectivity and low limit of detection (LOD) (104.56 ppb). Such sensing performance serves as a proof‐of‐concept for effectively combining solvated ion transport in nanoconfined space with microvillus structure design to develop advanced sensing systems. With such sensing materials, an evident response (23.52%), a similar response time (12 s), low LOD (498.05 ppb), and long‐term stability (at least 30 days) are achieved at the relative humidity of 70%. Mechanistic investigations revealed that effective transport of solvated ions is facilitated after sequential water and TEA surroundings while the microvillus structure significantly enhanced gas transport. Furthermore, the utility of such a sensing system is demonstrated in shrimp decay monitoring under wet conditions.

Experimental investigation of benzyl alcohol premixing effect on 5E concepts of compression ignition engine powered with lemongrass oil – diesel blend using response surface methodology

The corrected abstract is as follows.This article aims to study the benzyl alcohol premixing effect on the 5E concept of compression ignition engines powered with a lemongrass oil-diesel blend. The central composite approach is used to create the experimental matrix for the load (50–100%) and benzyl alcohol premixing ratio (0–20%). The experiment uses a computerized compression ignition, water-cooled, single-cylinder, naturally aspirated, four-stroke engine. The statistical model is tested using analysis of variance and confirmed at the 95% confidence level. Quadratic and linear models are created, and regression equations provide surface plots to analyse load–premixing ratio interaction on output response. Premixing of benzyl alcohol at 20% at maximum loads confirms 31.09%, 14.95%, 31.09%, 39.91%, 17.26%, 11.06%, 7.59%, 36.61%, and 4.34% higher enviroeconomic loss, thermal efficiency, brake-specific carbon dioxide, brake-specific nitrogen monoxide, cooling water exergy, sustainability index, volumetric efficiency, and exhaust gas temperature. It also has lower exergoeconomic loss, thermoeconomic loss, brake-specific energy consumption, brake-specific carbon monoxide, smoke opacity, brake-specific hydrocarbon fuel exergy, exhaust gas exergy, destructed exergy, and entropy generation by 23.64%, 30.4%, 17.50%, 13.6%, 81.30%, 18.1%, 27.77%, and 27.77%, respectively. It is necessary to control nitrogen monoxide using exhaust gas recirculation or selective catalytic reduction technology in future work.

Hydrogen production for the synergistic catalytic of modified-titanium dioxide supported nickel catalyst with potassium carbonate catalyst by supercritical water gasification of coal

Supercritical water gasification (SCWG) is a novel energy utilization technology for converting coal into hydrogen (H2)-rich gas products. Constructing a synergistic catalytic system is crucial for the enhanced production of H2 in the SCWG of coal. This work constructed a novel synergistic catalytic system, Mo, Co, and Cu were employed to modify titanium dioxide-supported nickel (Ni/TiO2) catalysts which were added to separate reaction zones independent with potassium carbonate (K2CO3) to exhibit synergistic effects, thereby enhancing H2 yield. The modification of Ni/TiO2 can improve the stability of the catalyst by causing lattice shrinkage of TiO2, the synergistic catalytic system exerted much higher carbon gasification efficiency (CGE) and H2 yield than the non-catalytic condition in this way. Among all the Ni/TiO2 catalysts, synergistic Ni-Cu/TiO2 with K2CO3, which has the smallest Ni particle size, maximized the CGE and H2 yield from 30.82% and 15.48 mol·kg-1 to 95.43% and 81.42mol·kg-1, respectively. The synergistic catalytic mechanism was further revealed, providing theoretical support for the regulation of hydrogen production from SCWG of coal.

Analysing the influence of flow channel structure on water–gas transport characteristics of carbon dioxide electrolyser with membrane structure

CO2 electrolysis is not only an effective means of alleviating global warming, but also offers a solution of long-term, large-scale energy storage. Within CO2 electrolysis cell, bipolar plate flow channel is a critical structural characteristic, playing a vital role in the efficient transport of multiphase reactive substances. However, the influence of various flow channel architecture on the performance of CO2 electrolysis remains largely unexplored. In this study, the complex process of multiphase mass transfer coupled with electrochemical reaction within CO2 electrolysis cell was simulated and verified through experiment. Then the influence of various flow channel structures on water-gas transport in the CO2 electrolysis cell was numerically studied. For different flow channel structures, the material distribution across different regions of the cell and the water flooding behaviour are systematically analysed. According to the characteristics of each channel structure, an improved flow channel design is proposed: a multi-serpentine flow channel at the cathode to ensure efficient gas transport capability, and a pin-type flow channel at the anode to reduce the amount of water traversing the membrane. This design aims to prevent cathode flooding while maintaining good gas transport capability. The research provides theoretical guidance for structural optimisation of CO2 electrolysis systems.

EXERGY ANALYSIS OF COAL THERMAL CONVERSION PROCESSES

To develop energy-saving technologies and facilities that use coal, it is essential to evaluate the energy potential of the resulting products. Additionally, it is necessary to determine their suitability for specific technologies, processes, and installations. Alongside the energy method, it is proposed to use the exergy method, which allows for the assessment of not only the quantitative but also the qualitative aspects of thermal conversion processes. Thermal conversion methods such as combustion and gasification are of interest for both energy and industrial applications. The study includes calculations of the exergy efficiency of coal thermal conversion products, based on which material and exergy balances were compiled for the gasification process under air and oxygen blast conditions, as well as for the combustion process. An analysis was conducted to evaluate the impact of process temperatures on the characteristics of coal thermal conversion products (composition, output, exergy). Additionally, the exergy efficiency coefficients (overall, chemical and physical exergy) for these thermal conversion methods were calculated. Based on the analysis, optimal operating modes for coal thermal conversion processes were determined, depending on the final goals of the obtained products. The advantages of high-temperature oxygen and air gasification were identified, characterized by low exergy losses (24.9–28.9 %) and high chemical potential (12–13.46 MJ/kg of coal). The exergy efficiency of the oxygen gasification process is 68.3–71.2 %, while for air gasification, it is 70.2– 76.3 %. It was also established that, to achieve the highest fuel utilization efficiency, it is advisable to utilize the heat of the produced syngas. The utilization of 1 MJ/kg of coal from the physical exergy of the gas increases the overall exergy efficiency of air gasification by 3.5 % and that of oxygen gasification by approximately 0.7 %. A comparison of the exergy efficiency of the processes was conducted, revealing that coal gasification is a more rational method of thermal conversion compared to traditional combustion. This is because the highest losses are observed during the combustion process, with an exergy efficiency of 64.8 %. During coal combustion, irreversible losses account for 35 % of its initial exergy.

Solid Solution Derived Cu Clusters on Partially Reduced CuCeO2 with Abundant Oxygen Vacancies Enable Efficient Reverse Water Gas Reaction.

The reverse water gas shift (RWGS) reaction provides a convenient approach to convert CO2 to CO, which facilitates to achieve the goals of carbon peaking and carbon neutrality. Herein, the Cu/CeO2 catalyst prepared by a co-precipitation method using a mixture of Na2CO3 and NaOH at pH of 10 (sample Cu/CeO2-10) achieved an intrinsic reaction rate of 428.4 mmol ⋅ gcat -1 ⋅ h-1 with 100 % CO selectivity at 400 °C and CO2/H2 ratio of 1 : 4, which is much higher than Cu/CeO2 prepared by impregnation and other methods. Various characterizations showed the highest fraction of CuCeO2 solid solution in the calcined Cu/CeO2-10, and formed highly dispersed Cu clusters (~2.5 nm) on partially reduced CuCeO2 solid solution with abundant of oxygen vacancies upon reduction. The Cu and oxygen vacancies facilitates the activation of H2 and CO2, respectively, resulting in lowered H2 and CO2 reaction orders. As a result, the synergy between the two components enhanced the overall RWGS activity with lowered activation energy. Moreover, the optimal catalyst is very stable in 24 h stability test without detectable agglomeration of Cu clusters.

Investigation on Syngas production from forest Biomass (Sapele, Sypo and Ayous) wood in the downdraft gasifier using Aspen plus and IC engine integration

This study aims to evaluate the potential for syngas production from three types of equatorial forestry biomass Sapele, Sipo, and Ayous using a downdraft gasifier. The main objective is to assess the energy potential of the produced syngas when used in an internal combustion engine with a 30% efficiency, coupled with a DC generator operating at 93% efficiency. The research focuses on determining the composition and energy output of syngas from these biomass types, as well as exploring the integration of downdraft gasification with internal combustion engines for localized energy production, particularly in decentralized power systems and microgrids. The research involved modeling and simulating the gasification process using Aspen Plus software. Proximate and ultimate analyses of the biomass samples were used to simulate gasification in a downdraft gasifier. The gasifier's performance was assessed through syngas composition analysis, focusing on energy output and overall system efficiency. The integration of downdraft gasification with an internal combustion engine was simulated to determine its feasibility in decentralized power systems and microgrids. The study revealed that all three biomass types produced syngas with high concentrations of carbon monoxide (CO) and hydrogen (H2), which are critical for energy generation. The lower heating value (LHV) of the syngas remained consistent among the samples, with Sapele at 13.51 MJ/Nm³, Sipo at 13.63 MJ/Nm³, and Ayous at 13.54 MJ/Nm³. Ayous achieved the highest gasification efficiency at 79.36%, followed by Sipo at 78.89% and Sapele at 76.05%. The simulation performed in Aspen Plus showed that Ayous produced the highest electric power output at 53.55 kW, followed by Sapele at 51.86 kW and Sipo at 49.18 kW. The results highlight the potential of equatorial forestry biomass, particularly Ayous, as a renewable energy source. All three biomass types can generate syngas of comparable quality in terms of energy content, with Ayous showing the highest efficiency. This research emphasizes the feasibility of using equatorial biomass for syngas production and its integration into internal combustion engines, supporting decentralized energy generation and reducing reliance on fossil fuels.

Triboelectric Nanogenerator Based on CPDs-WO3/MXene Bilayer Film for Triethylamine Sensing and Fish Meat Spoilage Detection.

With the increasing demand for food safety monitoring, the development of efficient, convenient, and green gas sensors has become a current research hotspot. Triboelectric nanogenerator (TENG) as a triethylamine sensor is a cutting-edge strategy for detection without the need for an additional power source. In this study, synthesized WO3/MXene materials were prepared and bilayer thin films of carbon quantum dots (CPDs)-WO3/MXene TENG. WO3 provides more active sites for improved material charge transfer efficiency. TENG achieved a maximum open-circuit voltage (Voc) of 30 V. The CPDs-WO3/MXene-3 TENG can also be used as a self-powered gas sensor (SPGS). As a charge-trapping layer, CPDs exhibit excellent charge trapping. The SPGS has a 53% response to 200 ppm TEA, and low detection at ppb level (139 ppb). The presence of WO3 improves the gas-sensing performance. Additionally, CPDs possess excellent conductivity and moisture resistance. Finally, it was studied to see how it reacts to TEA in fish meat under different conditions of spoilage. It provides approach to solving the transportation and preservation problems of fish meat.

Recent Developments on 2D-Materials for Gas Sensing Application.

The industrialization has severely impacted the ecosystem because of intensive use of chemicals and gases, causing the undesired outcomes such as hazardous gases, e.g., carbon monoxide (CO), nitrox oxide (NOx), ammonia (NH3), hydrogen (H2), hydrogen sulfide (H2S) and even volatile organic compounds. These hazardous gases are not only impacting the living beings but also the entire ecosystem. Thus, it becomes essential to monitor these gases for their efficient management. There are continuous efforts to realize such sensors, which rely on the functional materials properties. The widely used such sensors use metal oxide nanomaterials. However, these are not very sensitive and operate at higher temperatures. In contrast, two-dimensional (2D) materials such as Graphene, Borophene, MXenes, transition metal dichalcogenides (TMDs) including doping, functionalization, and heterostructures offer unique physical, chemical, and optoelectronic properties. The chemical properties with high specific surface area of 2D materials make them suitable for gas sensing applications. The present article covers the recent developments on 2D-TMDs layered material, including MoS2, WS2, h-BN, and Graphene, as well as their heterostructures, for gas sensing applications. The article also emphasizes their synthesis and characterization techniques, especially for 2D materials. The electronic properties of these materials are highly sensitive to any chemical changes, resulting in significant changes in their resistance. It led to the development of the highly scalable chemiresistive-based gas sensor. The sensing parameters such as sensitivity, selectivity, gas concentration, limit of detection, temperature, humidity, response, reproducibility, stability, recovery, and response time are discussed in detail to understand the gas sensing characteristics of these 2D materials. The article also includes the past developments, current status, and future scope of these materials as highly efficient gas sensors. Thus, this review article may lead the researchers to design and develop highly sensitive gas sensors based on 2D materials.

Gas Sensor for Efficient Acetone Detection and Application Based on Au-Modified ZnO Porous Nanofoam.

Toxic acetone gas emissions and leakage are a potential threat to the environment and human health. Gas sensors founded on metal oxide semiconductors (MOS) have become an effective strategy for toxic gas detection with their mature process. In the present work, an efficient acetone gas sensor based on Au-modified ZnO porous nanofoam (Au/ZnO) is synthesized by polyvinylpyrrolidone-blowing followed by a calcination method. XRD and XPS spectra were utilized to investigate its structure, while SEM and TEM characterized its morphology. The gas sensitivity of the Au/ZnO sensors was investigated in a static test system. The results reveal that the gas-sensitive performance of porous ZnO toward the acetone can be enhanced by adjusting the loading ratio of noble Au nanoparticles. Specifically, the Au/ZnO sensor prepared by the Au loading ratio of 3.0% (Au/ZnO-3.0%) achieved a 100 ppm acetone gas response of 20.02 at the optimum working temperature of 275 °C. Additionally, a portable electronic device used a STM32 primary control chip to integrate the Au/ZnO-3.0% gas sensor with other modules to achieve the function of detecting and alarming toxic acetone gas. This work is of great significance for efficiently detecting and reducing acetone emissions.

Prediction of syngas production in the gasification process of biomass employing adaptive neuro-fuzzy inference system along with meta-heuristic algorithms

Abstract Compared to fossil fuels, biomass fuels have minimal sulfur content, lower ash production, and significantly reduced emissions. The global need to reduce dependence on imported energy sources and preserve dwindling fossil fuel reserves underscores the importance of utilizing alternative energy resources. Biomass, with its abundant availability, presents a promising source for syngas production, even though the gasification procedure requires substantial energy due to its endothermic nature. Challenges related to the efficiency of biomass gasification and compliance with environmental standards have hindered economic viability. Much attention has been focused on predictive modeling of biomass gasification procedures to address these issues, necessitating robust frameworks capable of predicting parameters under varying operating conditions. This article introduces two hybrid frameworks, which are combined versions of Adaptive Neuro-Fuzzy Inference System (ANFIS) with Artificial Rabbits Optimization (ARO) and Crystal Structure Algorithm (CSA), based on proximate biomass values to predict elemental compositions (N2 and H2). These intelligent hybrid frameworks, trained with 70 % of biomass data, were further validated and tested with the remaining 15 % portions of the database. The frameworks were assessed based on some known performance metrics, namely, root mean squared error (RMSE), mean absolute error (MAE), coefficient of determination (R 2), RMSE-observations standard deviation ratio (RSR), and Nash-Sutcliffe Efficiency (NSE). Developed single and two hybrid frameworks compared and obtained outcomes revealed that both introduced optimizers efficiently promoted N2 and H2 estimation by ANFIS, especially CSA. R 2 values for ANCS were a maximum of 0.993 in both targets’ predictions. Also, minimum RMSE values of 1.007 and 1.470 related to N2 and H2 prediction emphasized the accuracy of ANCS, which is capable of being used in real-world applications.

Improving Room Temperature Formaldehyde Sensitivity with Samarium-Doped Titanium Dioxide

Abstract Samarium (Sm)-doped titanium dioxide (TiO₂) thin films were synthesized using the spray pyrolysis technique at 400°C, with Sm doping concentrations of 0, 2, 4, and 6 Wt.% to enhance structural, optical, morphological, and gas-sensing properties. The films, deposited on ultrasonically cleaned glass substrates, were characterized using X-ray diffraction , scanning electron microscopy, atomic force microscopy (AFM), and UV-Vis spectroscopy. Structural analysis revealed improved crystallinity and uniform surface morphology with Sm doping, while AFM indicated increased surface roughness, promoting gas adsorption. UV-Vis analysis showed a reduced energy bandgap, enhancing visible light absorption and gas-sensing performance. Gas sensing evaluations demonstrated high sensitivity to formaldehyde, with notable selectivity over ethanol, toluene, and xylene at room conditions. The 6 Wt.% Sm-doped TiO₂ film exhibited the highest response (17.4), with a detection limit of 5 ppm, and fast response (23 s) and recovery (27 s) times. These properties underline the potential of Sm-doped TiO₂ films for efficient room-temperature gas sensors. Their enhanced sensitivity, selectivity, and stability suggest promising applications in environmental monitoring and air quality management, particularly for formaldehyde detection and volatile organic compound discrimination.

3D-Printed Hydrogel Scaffolds Loaded with Flavanone@ZIF-8 Nanoparticles for Promoting Bacteria-Infected Wound Healing.

Bacterial-infected skin wounds caused by trauma remain a significant challenge in modern medicine. Clinically, there is a growing demand for wound dressings with exceptional antibacterial activity and robust regenerative properties. To address the need, this study proposes a novel multifunctional dressing designed to combine efficient gas exchange, effective microbial barriers, and precise drug delivery capabilities, thereby promoting cell proliferation and accelerating wound healing. This work reports the development of a 3D-printed hydrogel scaffold incorporating flavanone (FLA)-loaded ZIF-8 nanoparticles (FLA@ZIF-8 NPs) within a composite matrix of κ-carrageenan (KC) and konjac glucomannan (KGM). The scaffold forms a stable dual-network structure through the chelation of KC with potassium ions and intermolecular hydrogen bonding between KC and KGM. This dual-network structure not only enhances the mechanical stability of the scaffold but also improves its adaptability to complex wound environments. In mildly acidic wound conditions, FLA@ZIF-8 NPs release Zn2+ and flavanone in a controlled manner, providing sustained antibacterial effects and promoting wound healing. In vivo studies using a rat full-thickness infected wound model demonstrated that the FLA@ZIF-8/KC@KGM hydrogel scaffold significantly accelerated wound healing, showcasing its superior performance in the treatment of infected wounds.

Evaluating the sustainability of biohydrogen, biogas, and biohythane generation from agricultural, industrial, and municipal waste sources

AbstractBiofuel production from waste materials offers an effective solution for generating renewable energy in biohydrogen, biogas, and biohythane while reducing waste and recycling valuable nutrients. This review examines recent advances in biohydrogen and biogas production from renewable resources, focusing on the environmental impacts of different production techniques. It emphasizes life cycle analysis (LCA) as an important tool for assessing these impacts and discusses key production pathways and processes. The variability in LCA methodologies – including differences in software, impact categories, system boundaries, functional units, and analytical approaches – poses challenges for direct comparisons of studies. Despite these challenges, fermentation‐based production methods show substantial environmental advantages, such as reduced CO2 emissions, diminished ozone depletion potential, improved human health outcomes, lower ecotoxicity, and reduced fossil fuel use. Combining biohydrogen production with anaerobic digestion for biohythane generation demonstrates even greater energy efficiency and greenhouse gas reduction. Adopting waste‐to‐energy strategies grounded in life cycle principles could advance renewable energy system implementation and sustainability significantly.

Bioinspired Fern-like Fe2O3 Functionalized with Pd/PdO Nanoparticles for High-Performance Acetone Sensing.

The accurate monitoring and detection of acetone vapor are essential for environmental and human safety. Consequently, fern-like Fe2O3 with hierarchical vein-like structures is synthesized via a concise hydrothermal method. Compared with pure fern-like Fe2O3, fern-like Pd/PdO-Fe2O3 shows the best acetone-sensing characteristics, in terms of lower operating temperature (180 °C), better selectivity and excellent long-term stability. More importantly, the response value of the Pd/PdO-Fe2O3 sensor to 100 ppm acetone reaches as high as 73, which is 55% higher than that of pristine fern-like Fe2O3. This enhanced sensing performance can be ascribed to the synergistic effect between Pd/PdO and fern-like Fe2O3. On the one hand, Pd/PdO nanoparticles show favorable catalytic activity toward ionized oxygen molecules; meanwhile, the formation of the heterojunction between PdO and fern-like Fe2O3 plays an important role. On the other hand, the hierarchical nature of fern-like Fe2O3 promotes efficient gas diffusion throughout the structure. Based on its advantages, fern-like Pd/PdO-Fe2O3 becomes a satisfactory candidate for acetone gas sensors.

Towards an eco-social circular economy: exploring the feasibility study of pyrolysis on agricultural feedstocks

AbstractThe agricultural sector is challenging to decarbonise due to its reliance on heavy machinery and fossil fuels, which face issues when decarbonising via methods such as electrification. However, agriculture provides opportunities to generate renewable energy via biomass sources due to their abundance within this sector. This feasibility study used a continuous auger pyrolysis system to assess how straw waste from a medium-scale arable farm could convert energy from an external electrical source into usable chemical potential. Wheat, barley, oil seed rape (OSR), and bean straw have all been processed and pyrolysed under different temperatures and auger feed rates. The syngas product was then analysed, considering its composition and the lower heating value. Results indicate that the percentage of carbon monoxide and hydrogen and the total volume of syngas increased with temperature. In addition, the syngas’ energy quantity increased despite the product’s decreasing heating value. The case study’s annual energy demand was equal to 14.4% of the 3900 GJ maximum potential contained within the syngas, and thus it can be concluded that there is potential for the application of this system towards a circular economy. The system’s cold gas, net, and electrical conversion efficiency were also assessed with maximum values of 37.1%, 30.1%, and 174.4%, respectively. Furthermore, the statistical analysis confirms high predictability for wheat, barley, bean, and OSR feedstocks, with a general linear model showing high accuracy across all.

Scaling up Trickle Bed Reactor for Gas Fermentation Technology: The Effect of Temperature and Reactor Characteristics on Mass Transfer

The increasing demand for efficient and sustainable industrial processes has accelerated research into green alternatives. Gas fermentation in a trickle bed reactor is a promising technology; however, optimal scaling up is still challenging. A mass transfer model is crucial for identifying bottlenecks and suggesting design improvements to optimize the scale-up of TBR for gas fermentation. This study explores the effects of temperature, reactor dimensions, and packing material size on the volumetric mass transfer coefficient (kLa) in a commercial-scale trickle bed reactor (TBR). Using dynamic mass transfer modeling, the research results highlight that thermophilic conditions (60 °C) significantly enhance kLa and mass transfer rates for H2, CO, and CO2, despite reduced gas solubility at higher temperatures. Additionally, packing material of smaller particles improves kLa by increasing the surface for gas–liquid interaction, while reactor dimensions, particularly volume and diameter, are shown to critically influence kLa. This study provides valuable insights into optimizing TBR design and scale-up, emphasizing the importance of thermophilic conditions, proper packing material selection, and reactor geometry for efficient gas–liquid mass transfer in syngas (a mixture of H2, CO, and CO2) biological conversion. Overall, the findings offer practical guidelines for enhancing the performance of industrial-scale TBR systems.