Gas Reduction Research Articles

Mitigation-driven global heat imbalance in the late 21st century

While the changes in ocean heat uptake in a warming climate have been well explored, the changes in response to climate mitigation efforts remain unclear. Using coupled climate model simulations, here we find that in response to a hypothesized reduction of greenhouse gases in the late 21st century, ocean heat uptake would significantly decline in all ocean basins except the North Atlantic, where a persistently weakened Atlantic meridional overturning circulation results in sustained heat uptake. These prolonged circulation anomalies further lead to interbasin heat exchanges, characterized by a sustained heat export from the Atlantic to the Southern Ocean and a portion of heat transfer from the Southern Ocean to the Indo-Pacific. Due to ocean heat uptake decline and interbasin heat export, the Southern Ocean experiences the strongest decline in ocean heat storage therefore emerging as the primary heat exchanger, while heat changes in the Indo-Pacific basin are relatively limited.

Comparative analysis of Environmental Impact of Each Building Material using Life Cycle assessment(LCA)_Focusing on Types of Construction Wood and Concrete

Objectives:The construction sector is a very important sector in achieving carbon neutrality. In modern society, construction has grown rapidly, and basic materials such as cement and concrete have contributed greatly to the development of construction. These materials emit a large amount of global warming substances during the raw material extraction and production process, causing serious environmental pollution. In order to establish a carbon reduction strategy to slow down global warming, we compared the environmental impacts of each building material and showed the current situation.Methods:The LCI DB for the construction materials used in the two-story wooden house (Building area 128.67m2, total floor area 235.73m2) located in the National Institute of Forest Science was extracted. Then, the data for LCA was processed and performed through the life cycle assessment methodology for the resources consumed from raw material collection, material production, and transportation stages. Then, based on the environmental performance labeling impact assessment method, a study was conducted on the environmental impact categories of the actual construction materials used and comparisons with other construction materials.Results and Discussion:When analyzing the environmental impact of concrete [25-21-120] and construction wood used in wooden house, the environmental impact was found to be 98.79% higher on average in the pre-manufacturing stage than in the manufacturing stage, and construction wood was confirmed to have a reduction effect of 62.21 kg CO2-eq per 1 m3 compared to concrete. Through the scenario, there was a carbon reduction effect of up to 36% when the entire area was replaced with wood. In addition, the environmental impact by major construction material was quantitatively quantified.Conclusion:When building a wooden house, reducing the amount of concrete equivalent to the amount of wood is expected to have a greenhouse gas reduction effect, so it is time to activate construction wood from the production process to the post-production stage to replace concrete. In addition, follow-up research on the development of construction technology with low environmental impact during construction should be continued. This study is expected to be used as a useful indicator for R&D and policies in the construction field in the future, as it quantitatively quantified the amount of CO2 reduction per m3 when replacing concrete with construction wood and numerically compared and analyzed six major environmental impact categories by major construction materials.

Evaluation of selected rice cultivars' phenotypic traits and chlorophyll content under sub-mergence stress

Currently, rice production in Nigeria is on the increase with the aim of meeting the nation’s need but floods (mainly seasonal) has been among the major factors limiting rice production. Rice is generally a semi aquatic plant well adapted to partially flooded fields but flash flooding may leads to complete submergence there by resulting into huge economic losses mainly due to reduction in gases (hypoxia) and light intensity needed for photosynthesis. The research was conducted at the Biological Garden, Department of Biological Sciences, Federal University Birnin Kebbi. The experiment was set off in a Completely Randomized Design (CRD) consisting of four rice cultivars with control and three replications. Length of internodes, number of nodes per plant, plant height, root length and chlorophyll contents were evaluated using standard methods and protocols. The study analyzed the impact of flooding on rice cultivars, finding significant differences in node number, internode length, plant height, root lengths, and chlorophyll content. The highest number of nodes was found in CP Yartunga, followed by Faro with 6.33 per plant. The highest plant height was 15.50 cm in Faro, while the highest chlorophyll content was 0.41 mg/g in CP 44. The research reveals that rice cultivars recover from flooding stress, with CP Yartunga having the highest number of nodes per plant and Faro having the highest internode length. No significant differences were found in plant height, root length, or chlorophyll content among the evaluated cultivars. Faro had the lowest chlorophyll content. The study reveals that under stress, chlorophyll content in various locations decreases significantly, with a significant drop in recovery and node numbers. Lastly, node recovery is substantial, suggesting lower injury levels. The present study suggests that cultivars like Faro and CP 44 show better resilience, suggesting potential breeding programs focusing on structural traits.

Sustainable biomass derived natural surfactant of soybean seeds in fly ash industrial waste utilization for carbon storage: Evaluation of environmental impact

The rising carbon emissions challenge global environmental sustainability and climate stability. This study aims to advance climate change mitigation by integrating fly ash and natural surfactant into CO2 sequestration strategies. Fly ash, a by-product of industrial processes, presents an opportunity for innovative reuse. By combining fly ash with a natural surfactant extracted from soybean seeds, both industrial waste management and greenhouse gas reduction can be addressed. The surfactant was characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, surface tension, and electrical conductivity measurements, confirming saponin presence with a critical micelle concentration of 0.3 wt%. Pressure decay studies revealed that a (5 wt% fly ash + NS) demonstrated the highest CO2 absorption, supported by microscopic analysis. Further research on optimizing reaction conditions and kinetics of mineralization could enhance this method’s efficiency and scalability for broader application.

Optimization of BOG Reliquefaction Process of Carbon Dioxide Considering Nitrogen Content

<i>As the importance of carbon capture and storage (CCS) technology increases for greenhouse gas reduction, CO<sub>2</sub> transportation technology is also becoming crucial. Efficiently handling boil-off gas (BOG) generated during voyages is particularly important. This paper proposes a process incorporating two-stage separation and mixed refrigerants to reliquefy CO<sub>2</sub> BOG containing nitrogen efficiently. This process was optimized based on specific power consumption (SPC) criteria and compared with the conventional single-stage separation using an ammonia refrigerant. The two-stage separation allows the removal of non-condensable gases, such as nitrogen, before expansion, and the use of mixed refrigerants enables more efficient heat exchange than ammonia refrigerants, improving the reliquefaction rate. As a result, the proposed process reduced SPC by up to 8.8 % with a nitrogen content of 5 mol% and up to 74.7 % with a nitrogen content of 15 mol%. In addition, the proposed process achieved a reliquefaction rate of over 74.2 % across all nitrogen content ranges of 5–15 mol%.</i>

Investigating the existence of an osmotic barrier between xylem fibres and vessels in sugar maple (Acer saccharum) using microCT.

Sugar maples (Acer saccharum Marshall) develop elevated stem pressures in springtime through the compression and expansion of gas bubbles present within xylem fibres. The stability of this gas within the fibres is hypothesised to be due to the elevated sugar concentration of maple sap and the presence of an osmotic barrier between fibres and vessels. Without this osmotic barrier gas bubbles are predicted to dissolve rapidly. In this work we investigated the existence of this osmotic barrier. We quantified the fraction of the xylem occupied by gas-filled fibres using synchrotron based microCT. After imaging fresh stem segments we perfused them with either a 2% sucrose solution or water, imaging again following perfusion. In this way we directly observed how total gas present in the fibres changed when an osmotic pressure difference should be present, with the 2% sucrose solution, and when it is absent, with the water. Following a first round of perfusion we perfused stem segments with the other perfusate, repeating this multiple times to observe how switching perfusates affected gas-filled fibres. We found that perfusing stem segments with water resulted in a significant reduction in the xylem fibre gas, but perfusing stem segments with a sucrose solution did not significantly reduce the gas in the fibres. These results support the hypothesis that an osmotic barrier exists between fibres and vessels.

Gatekeeper™ Prostheses Implants in the Anal Canal for Gas Incontinence and Soiling: Long-Term Follow-Up

Introduction: Although several treatments for faecal incontinence are available, gas incontinence (GI) and soiling are difficult to manage. The aim of this study is to evaluate Gatekeeper™ for this subtype of faecal incontinence. Methods: Prospective single-centre case series. Patients with mainly soiling and/or GI were treated with polyacrylonitrile prostheses. An evaluation was performed with a 3-week continence diary. St. Mark’s score and a Visual Analogue Scale (VAS) were used to study the patient’s continence perception and surgical satisfaction, at baseline and 1, 3, 6, 12, and 24 months postoperatively. 3D-Endoanal Ultrasound and Anorectal Manometry were performed at baseline and postoperatively. Results: A total of 13 patients were enrolled (11 women), aged (median (IQR)) 62 (13) years, and all implants were uneventful. A significant reduction in soiling and GI episodes was documented at 1 year, 7 (18) baseline days of soiling/3 weeks vs. 2 (4) (p = 0.002); 13 (13) baseline episodes of GI/3 weeks vs. 4 (10) (p = 0.01). This improvement was correlated with a significant increase in VAS (0–10), 3 (2, 5) baseline vs. 7 (1, 5) (p = 0.03), and maintained throughout the follow-up. There was complete remission or significant improvement defined as >70% reduction in gas and soiling days in 6 patients at 2 years follow-up. Soiling episodes were reduced ≥70% in 8/11 patients (72.7%). Nine (70%) patients would repeat the treatment. Conclusions: Gatekeeper™ is a safe, minimally invasive treatment for soiling and GI. A significant reduction in soiling and GI was observed in our series, with a better response to soiling. Most of the patients would repeat the treatment. Other studies are needed to confirm these findings in this subgroup of FI patients.

Redox Couple Strategy for Improving the Oxygen Redox Activity and Reversibility of Li- and Mn-Rich Cathode Materials.

The specific capacity of Li- and Mn-rich layered oxide (LMROs) cathodes can be enhanced by the oxidation of lattice oxygen at high voltages. Nevertheless, an irreversible oxygen loss emerges with cycling, which triggers interlocking surface/interface issues and results in the fast deterioration of cycling performance. Herein, we prepare a surface modified LMRO electrode by one step doctor-blade casting and introducing a benzoquinone species DBBQ redox couple. The electrochemical test shows that the DBBQ-modified electrode has a high reversible capacity (>320 mAh g-1) and excellent rate performance, while the cyclic stability has been significantly improved as well. The capacity retention reaches as high as 93.3% after 500 cycles at 1 C. Mechanism analysis shows that DBBQ can not only play a redox couple in LMROs which achieves the adsorption and reduction of surface oxygen gas but also significantly enhance anionic redox in the bulk, thus realizing extraordinary capacity.

Environmental and Welfare Effects of Large-Scale Integration of Renewables in the Electricity Sector

AbstractThe 2022 energy crisis highlighted the dependence of the Europe electricity sector on imported natural gas and the need to accelerate the adoption of renewables to the power system. However, operating a reliable power system with high share of renewables might require curtailing some renewables and activating conventional generators not scheduled in the day-ahead markets to ensure system reliability. These actions can result in environmental impacts, higher system costs and welfare impacts for customers. We use a novel high-granularity data from the Spanish power system for the period 2019–2022 to estimate the effects of these actions and forecast future impact of implementing ambitious targets of the European Gas Reduction Plan. We show that reliance on conventional generators will sharply increase with the addition of renewables. However, higher electricity consumption reduces the negative welfare impacts of integrating renewables. Until renewables and storage technologies advance further, conventional generators are needed for reliable operation of the systems.

Resource Adequacy and Integration of Renewables in Light of US, EU, and Pakistan’s Evolving Power Sector

This study investigates resource adequacy and renewable energy integration in the United States, European Union, and Pakistan amid global energy market liberalization and greenhouse gas reduction efforts. It explores how these regions are adapting to the surge in renewable sources like wind and solar, which, despite their financial and environmental benefits, challenge resource adequacy and the economic viability of traditional energy sources. In the US and EU, significant improvements have been introduced in wholesale electricity markets and capacity accreditation mechanisms, which enhanced the large-scale deployment of renewables. This shift has prompted a reevaluation of resource adequacy, leading to the increased deployment of battery storage and demand response. Presently, gas-based generation is largely upholding resource adequacy; however, future trends indicate a move towards greater consumer participation, energy efficiency, and utility-scale storage, with a decline in fossil fuel use. Pakistan aims to adopt a liberalized market structure by balancing competitive markets with legacy contracts. Public pressure is driving a shift from costly fossil-based generation to renewables. Similarly, a trend in the rise of behind-the-meter solar generation can be witnessed. In the future, Pakistan may also experience resource adequacy challenges. It will likely need to implement battery storage, demand response, and modern capacity accreditation tools, by drawing lessons from developed markets.

A study on the microstructure and power generation performance of colored BIPV modules

The need for greenhouse gas reduction and carbon neutrality is increasing, and the Building Integrated Photovoltaic (BIPV) power generation system is emerging as a key element. However, colored BIPV modules that enhance the aesthetic value of buildings have challenges in maintaining power generation efficiency due to their varied optical properties. This work investigates the structural, elemental, and power generation of colored BIPV modules fabricated using Plasma Enhanced Chemical Vapor Deposition (PECVD), inorganic pigment dyeing (HAZE), and color dot printing (DOT) in comparison to a conventional BIPV module without color treatment. Comprehensive structural and elemental analyses were performed, and optical properties were assessed. Power generation performance was measured using an Outdoor-exposed Power Generation Evaluation (OPGE) test at various tilt angles and azimuths. The results indicated a 57.2 % decrease in power output for the PECVD module, while the DOT and HAZE modules showed a reduction of approximately 30 % compared to the reference module. The power output of the colored modules decreased compared to the conventional ones due to higher light reflectance. However, to enhance efficiency, an improved optical design was developed, reducing light reflectance by over 57 % on average. This provides the potential for optimizing both the aesthetic and functional aspects.

Micro-enema immediately prior to prostate MRI: effects on rectal gas, image quality and PI-QUAL score.

Our aim was to determine whether the administration of a micro-enema immediately prior to prostate MRI is associated with a reduction in rectal gas, gas related artifacts and an improvement in image quality and PI-QUAL score. This retrospective analysis enrolled 171 patients who underwent multiparametric 3T prostate MRI at our institution between January 2021 and September 2022. 86 patients received a micro-enema, and a further 85 patients did not. Two fellowship trained abdominal radiologists were blinded and independently reviewed each prostate MRI, recording scores on a dedicated scoring sheet. The quality of T2 weighted (T2W), diffusion weighted (DWI), and dynamic contrast enhancement (DCE) images were assessed according to standardised scales supported in the literature. In addition, gas related artifacts and rectal gas level were examined. An independent-samples Mann-Whitney U and t-test were performed, comparing both the median and mean score between micro-enema and no micro-enema groups for each reader. Spearman's correlation was used to determine the strength of relationship between variables. A quadratic weighted Cohen's Kappa and percent agreement were used to assess inter-observer agreement. Image quality was improved in those who received the micro-enema compared to those who did not according to the visual grading scale on the DWI sequence for both readers (reader 1: median 4 vs. 4, p < 0.001, mean 4.27 vs. 3.92, p < 0.001; reader 2: median 5 vs. 4, p < 0.001, mean 4.74 vs. 4.14, p < 0.001). PI-QUAL score was significantly improved in the micro-enema group for reader 2 only (reader 1: median 4 vs. 4, p = 0.25, mean 3.99 vs. 4.08, p = 0.21; reader 2: median 5 vs. 5, p = 0.01, mean 4.95 vs. 4.78, p = 0.01). Visual grading score for both the T2W and DCE images was not significantly different. Rectal gas level was lower in patients who received the micro-enema for both readers (reader 1: median 2 vs. 4, p < 0.001, mean 2.12 vs. 3.60, p < 0.001; reader 2: median 1 vs. 2, p < 0.001, mean 1.37 vs. 2.48, p < 0.001), correlating with a lower score for gas-related artifacts (reader 1: median 1 vs. 2, p < 0.001, mean 1.50 vs. 1.92, p < 0.001; reader 2: median 1 vs. 1, p < 0.001, mean 1.16 vs. 1.71, p < 0.001) in this group. Correlation between rectal gas level and gas-related artifacts on DWI regardless of whether a micro-enema was given was strong (rs = 0.71, p < 0.001). Correlation was moderate to strong between rectal gas level and image quality on DWI (rs = -0.63, p < 0.001). There was only 1 (1.2%) borderline diagnostic or non-diagnostic DWI sequence in those who received the micro-enema, compared to 9 (10.6%) in those who did not (p = 0.009). Interobserver agreement was moderate for image quality on DWI, gas related artifacts and rectal gas level (weighted kappa values of 0.52, 0.49 and 0.53 respectively). The administration of a micro-enema immediately prior to prostate MRI is associated with a significant improvement in image quality on the DWI sequence compared to no bowel preparation. This is mediated through a reduction in rectal gas and gas related artifacts. Improvements in PI-QUAL score was mixed between readers.

Uncertainty of climate models and policy implications: a European perspective

AbstractIn this paper we show that both climate models and economic models studying the effects of climate change are characterized by high uncertainty. Hence, far reaching policy implications such as the net zero goal lack a definite scientific foundation. Nevertheless, it cannot be excluded that the continued global warming will go along with high damages in the future. Therefore, decreasing greenhouse gas emissions could be justified due to the precautionary motif. However, there are strong signals from non-European economic regions that they definitely put a higher weight on economic growth rather than on greenhouse gas mitigation. The reduction of greenhouse gases in the European Union cause tremendous costs without influencing the climate on earth. Further, these investments do not raise the aggregate stock of productive capital nor do they lead to factor augmenting technical progress. Therefore, the net zero goal of the Green Deal of the European Union is to be seen sceptical.

Recent Trends in the Synthesis of Monomers for Furanoate Polyesters and Their Nanocomposites’ Fabrication as a Sustainable Packaging Material

Furanoate polyesters are an extremely promising new class of materials for packaging applications, particularly furanoate-based nanocomposites, which have gained a high interest level in research and development in both academia and industries. The monomers utilised for the synthesis of furanoate-based polyesters were derived from lignocellulosic biomass, which is essential for both eco-friendliness and sustainability. Also, these polyesters have a lower carbon footprint compared to fossil-based plastics, contributing to greenhouse gas reduction. The furanoate-based nanocomposites exhibit enhanced performance characteristics, such as high thermal stability, excellent mechanical strength, superior barrier resistance, and good bacteriostatic rate, making them suitable for a wide range of industrial applications, especially for food-packaging applications. This paper reviews the recent trends in the synthesis routes of monomers, such as the various catalytic activities involved in the oxidation of 5(hydroxymethyl)furfural (HMF) into 2,5-furandicarboxylic acid (FDCA) and its ester, dimethyl furan-2,5-dicarboxylate (DMFD). In addition, this review explores the fabrication of different furanoate-based nanocomposites prepared by in situ polymerization, by melt mixing or solvent evaporation methods, and by using different types of nanoparticles to enhance the overall material properties of the resulting nanocomposites. Emphasis was given to presenting the effect of these nanoparticles on the furanoate polyester’s properties.

Onboard amino acid salt-based CO2 integrated absorption and mineralization: Kinetics, mechanism, economics and life cycle

The International Maritime Organization's ambitious greenhouse gas reduction strategy is driving efforts to capture carbon from marine engine exhaust gas. Onboard carbon capture and storage (OCCS) faced significant challenges, particularly due to the substantial thermal energy requirements during the capture process and the complexities of transporting captured CO2 to storage facilities. The integrated CO2 absorption and mineralization (IAM) process, a thermodynamically downhill process, offered a potential solution for rapidly absorbing and sequestering CO2 in-situ. In this study, a single-step amino acid salt-based IAM process was employed to address carbon emissions from ships. Under optimized conditions, over 85 % of the CO2 in simulated marine engine exhaust gas was captured and completely converted to calcium carbonate using a potassium glycinate/ calcium hydroxide blend absorption slurry. This approach tackled the key challenges of effectively capturing CO2 from ships, while minimizing energy consumption, and ensuring the safe storage of the captured CO2. A case study on a 1700 TEU container ship evaluated the economic benefits and global warming potential of the OCCS system, indicating that capturing CO2 from ships could be profitable (87.2 $/ton CO2) and calcium carbonate could be a commercial product. Despite high-carbon-intensity absorbents (such as calcium hydroxide) partially offset the carbon reduction effort, resulting in a decline of carbon capture efficiency from 85 % to 44 %. The proposed amino acid salt-based IAM method could be considered a promising technique for reducing carbon emissions from ships, providing a feasible technical means for achieving the International Maritime Organization's ambition strategy for zero-carbon shipping.

Animal welfare has priority: Swiss consumers’ preferences for animal welfare, greenhouse gas reductions and other sustainability improvements in dairy products

Animal welfare is at the forefront of the debate on sustainable food systems. However, animal welfare improvements often imply higher costs for producers. We explored whether Swiss consumers are willing to contribute monetarily to such improvements through an increase in prices of butter or milk. Based on a discrete choice experiment on 986 Swiss consumers, we investigated preferences for two animal welfare improvements in the dairy industry – loose housing and farm killing – as well as for organic production, origin of product, and greenhouse gas (GHG) reductions. Furthermore, we investigated how consumers perceive a potential conflict between of GHG reductions and animal welfare concerns. Half of our sample faced increases in milk prices; the other half faced increases in butter prices. Findings indicate that animal welfare is of higher importance to consumers when compared to the other attributes under analysis. Consumers oppose GHG reductions associated with deteriorations in animal welfare and are willing to pay for improvements in housing conditions and a less stressful killing of the animals. Improvements in animal welfare could be crucial for dairy industry actors and provide strong arguments in communicating the benefits of dairy products to consumers.

Methane-driven microbial nitrous oxide production and reduction in denitrifying anaerobic methane oxidation cultures

Methane (CH4) and nitrous oxide (N2O) are two important greenhouse gases (GHGs), and it is very important to achieve the reduction of both gases in the case of increasingly serious climate change. The study confirms the simultaneous mitigation of potent GHGs N2O and CH4 in denitrifying anaerobic methane oxidation (DAMO) enrichment, supplementing the understanding that DAMO microorganisms do not produce and reduce N2O. We observed rapid accumulation and consumption of N2O in DAMO cultures subjected to high nitrate and nitrite loadings. Moreover, when N2O served as the sole electron acceptor, a significant correlation was found between the flux of N2O reduction and CH4 oxidation. Inhibition of the particulate methane monooxygenase (pMMO) led to a notable decrease of 95% in N2O reduction and 50% in CH4 oxidation. Metagenomic analysis revealed that Candidatus Methanoperedens and Candidatus Methylomirabilis were the dominant genera, with all functional genes related to denitrification and methane oxidation identified, including NO reductase (nor) of Ca. Methylomirabilis. Transcriptomic analysis further confirmed that the transcripts of nor were one order of magnitude higher than other functional genes. These results indicate that when the substrate NO2- surpasses the dismutation capacity of NO dismutase (nod), DAMO bacteria can alternatively induce nor to reduce NO to N2O. However, considering that N2O reductase (nosZ) is still missing in Ca. Methylomirabilis, the partner Methyloversatilis may be responsible for N2O reduction. Our results provide new insights into the link between GHG emissions in DAMO systems under anaerobic conditions.

Convert food waste into easily biodegradable liquid substrate: New insights into wet oxidation as a pretreatment for anaerobic digestion

This study is the first comprehensive investigation into the industrial application of wet oxidation (WO) for food waste (FW) valorization. We analyzed the physicochemical properties of WO products and performed a material flow analysis. WO achieved a 25.7 % reduction in chemical oxygen demand and produced liquid and solid products suitable for high-value applications. The liquid product featured high biodegradability (B/C ratio of 0.65), significant BOD5 (33 ± 9 g/L), low total solids (3.5 % ± 0.4 %), and low metal concentrations, making it ideal for high-efficiency anaerobic digestion or as a carbon source in wastewater treatment. The solid product, with a total solids content of 63.9 % ± 1.4 %, is a potential organic fertilizer alternative. Life cycle assessment showed that WO-related scenarios offered superior greenhouse gas (GHG) reduction compared to conventional anaerobic digestion (11.30 kg CO2-eq/t FW slurry). The most effective scenario, combining WO with a carbon source and organic fertilizer alternative, achieved a GHG reduction of −21.80 kg CO2-eq/t FW slurry. Consequently, this study demonstrates that WO, as a pretreatment for food waste valorization, is both technically feasible and environmentally sound, offering valuable engineering references for the implementation of high-efficiency anaerobic digestion processes for food waste.

Experimental investigation on product and temperature distribution in a continuous flow packed-bed reactor for dodecahydro-N-ethylcarbazole dehydrogenation

The dehydrogenation of dodecahydro-N-ethylcarbazole (H12-NEC) generates enormous gas accompanied by intense heat absorption, affecting heat and mass transfer in porous catalysts. A packed-bed reactor equipped with a temperature measurement device was designed to investigate the continuous flow dehydrogenation of H12-NEC. The effects of weight hourly space velocity (WHSV), reaction temperature, catalyst particle size, and pressure were evaluated. The results reveal that the volume flow rate of hydrogen will increase with the increase of WHSV. And the reduction of gas–liquid ratio and catalyst particle size facilitates heat transfer causing a more uniform axial temperature distribution within the reactor. As the temperature rises, the hydrogen yield increases along with more by-products. 456 K and 2 mm of catalyst particle size are determined to be the optimal reaction conditions in the study, achieving the hydrogen production rate of 9.61 molH2·gPd-1·h-1. With pressure increasing, the hydrogen yield gradually decreases, but the decreased evaporation of H12-NEC results in a smaller temperature difference between the reactor and heating wall. A comparison with the thermodynamic equilibrium model reveals that the effect of pressure on chemical equilibrium may be more significant than the temperature.

An Overview of H2 and CH4 as Environmentally Sustainable Alternative Reductants to C for Chromite Smelting

The application of hydrogen (H2) and methane (CH4) as gaseous reductants for pure chromite (FeCr2O4) is reviewed in four theoretical approaches. These approaches are evaluated against the conventional process, where the sole reductant is a solid carbon (C) source. The sustainability is measured by gaseous carbon monoxide (CO(g)) formation, determined by the reaction stoichiometry of each theoretical approach. Decreased CO(g) formation is critical for alleviating the adverse environmental impact of ferroalloy production. The prereduction of FeCr2O4 by H2, followed by reduction by CH4 shows the largest decrease in CO(g) formation, i.e., a 75% decrease, compared to the conventional process. Furthermore, the H2‐based prereduction and CH4‐based primary reduction occur at lower temperatures than C‐based reduction, due to kinetic advantages, and thus decrease energy consumption. The overview discusses the environmental impact of substituting C with H2 and CH4 and briefly discusses how it can be implemented in industry.