Water Steam Research Articles

Comparative Study of Si−O−Al and Si−O−Si Bond Stability in HZSM‐5 Zeolite Under Steam and Hot Liquid Water Environments

AbstractUnderstanding the changes in the zeolite framework and catalytic active sites during zeolite‐based vapor‐phase and aqueous catalytic processes is crucial. Herein, the evolution of framework T atoms (Si and Al) in ammonium hexafluorosilicate (AHFS)‐treated HZSM‐5 zeolite under steam and hot liquid water (HLW) environments was inverstigated using various characterization techniques. In HLW, Si−O−Si bonds exhibit poorer hydrothermal stability than Si−O−Al bonds, in contrast to steam. Significant Si atom leaching occurs regardless of whether the framework tetrahedral Al atoms (Al(IV)‐1) are removed. Similar to steam, Al(IV)‐1 species in HLW sequentially evolve into partially coordinated framework Al species and then into extra‐framework Al (EFAL) species through partial and complete hydrolysis. The generated EFAL species act as Lewis acid sites, but their local structures or chemical environments may differ. These findings reveal the difference in the T−O−T bonds attacked by water molecules: the Si−O−Al bonds are primarily attacked in steam, whereas the Si−O−Si bond are primarily attacked in HLW.

Antioxidant potential of olive leaf (<i>Olea europaea L.</i>) sustainable extracts evaluated in vitro and minced beef meat

In this work, by using water steam only, two antioxidant extracts were obtained from olive leaves (Olea europaea L.), a by-product of olive oil chain. Olive leaf extracts (OLEs) were tested as such (water extract: WE) and partially purified with ethyl acetate (ethyl acetate [EA] extract). Total phenols were 7.4 mg/mL and 3.8 mg/mL in WE and EA final solutions, respectively, evidencing a different composition by high-performance liquid chromatography analysis. Both extracts were evaluated in vitro in comparison to pure hydroxytyrosol (Hy). A 2,2-diphenyl-1-picrylhydrazyl (DPPH) EC50 of 57.6, 76.5, and 39.7 µg/mL and a ferric reducing antioxidant power EC50 of 84.8, 69.9, 41.2 µg/mL were determined for WE, EA, and Hy solution, respectively. The Rancimat induction time determined at 120°C in a lard sample with 200-ppm total phenol equivalent addition of WE, EA, and Hy was 8.92 h, 12.74 h, and 7.27 h, respectively (vs. 2.24 h for lard only). Extracts were added at the same dose (200 ppm) to minced beef patties that were put in closed containers under controlled air headspace composition (NA, natural air; HOA, modified air with 80% O2; and 20% N2) and stored at 4°C up to 10 days. Extracts showed significant effectiveness in contrasting decrease of O2 level in containers as well as pH and color changes of patties. A significant increase (expressed as mg of malondialdehyde MDA/kg; thiobarbituric acid-reactive substance (TBARS) assay was conducted in control samples at an interval of 0–10 days (from 0.52 to 0.78 mg of MDA/kg in NA samples; and from 0.55 to 1.31 mg of MDA/kg in HOA samples), while minimal changes were observed in treated samples. These findings suggest a potential use of OLEs for maintaining quality and oxidative stability of beef patties during storage.

Identification and Evaluation of Synergy Between Carbon Emissions and Air Pollutants in Inter-Industrial Trade Among Provinces in China

With the vigorous promotion in China of efforts to reduce pollution and carbon emissions, examining their synergies becomes increasingly crucial. This study used the multi-regional input–output (MRIO) table to build the consumption-based industrial emissions inventories of CO2 and three major air pollutants (PM2.5, NOx, and SO2) and constructed synergistic emission indices of the intensity and magnitude to identify and evaluate the synergy between carbon emissions and air pollutants in inter-industrial trade among 30 provinces in mainland China. The results show that more than 85% and 40% of inter-provincial and inter-industrial trades have synergistic emissions between CO2 and air pollutants, respectively. We identified 77 inter-provincial trades and 84 inter-industrial trades among provinces with strong synergistic emissions. They are mainly reflected in the demand of the construction industry in Zhejiang and Guangdong for the nonmetal mineral products manufacturing industry in Henan, and the metal smelting and processing industry in Hebei, along with the demand of the service industry in Beijing for the electric power, steam, and hot water production and supply industry in Inner Mongolia. Our study provides new insights into the synergistic reduction of CO2 and air pollutants within the supply chain, thereby enriching the discourse on regional and industrial synergies in achieving sustainable development goals.

Catalytic Effects of Potassium Concentration on Steam Gasification of Biofuels Blended from Olive Mill Solid Wastes and Pine Sawdust for a Sustainable Energy of Syngas

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

Importance of Clay Swelling on the Efficacy of Cyclic Steam Stimulation in the East Moldabek Formation in Kazakhstan

Both steam and hot water flooding of high-viscosity oils in the presence of swelling clays are difficult methods for producing oil efficiently because of potential formation permeability reduction. This paper pertains to heavy oil recovery from the East Moldabek formation where the oil API gravity is about 22 and is inundated with swelling clays. To achieve this, we used the IntersectTM reservoir simulator to compare oil recovery economics using both hot water and steam injection as a function of steam cycle duration, temperature, and steam dryness. We also studied clay swelling in the East Moldabek formation where clay poses a significant challenge due to its impact on permeability reduction. In this research, we developed an equation based on experimental data to establish a relationship between water mineralization and permeability in the East Moldabek formation. The equation provides valuable insight on how to mitigate clay swelling which is crucial for enhancing oil recovery efficiency—especially in sandstone reservoirs. Our modeling studies provide the recovery efficiencies for salinities of the hot water EOR versus cyclic steam EOR methods in a formation containing swelling clays. Specifically, the reduction in formation permeability as a function of the distilled water fraction is the controlling parameter in hot water or steam flooding—when the formation water mixture becomes less saline, oil recovery decreases. Our research shows that clay swelling can significantly impact cyclic steam stimulation outcomes, potentially reducing its effectiveness, while hot water flooding may offer a more cost-effective and operationally feasible solution in formations where clay swelling is a concern. Economic analysis reveals the potential for achieving an optimal favorable condition for hot water injection. Therefore, this paper provides a guideline on how to conduct thermal oil recovery for heavy oils in fields with high clay content such as the East Moldabek deposit.

Performance improvement and multi-objective optimization of a two-stage and dual-temperature ejector auto-cascade refrigeration cycle driven by the waste heat

This paper presents a two-stage and dual-temperature ejector auto-cascade refrigeration cycle (TEARC) driven by the waste hot water and low-pressure exhaust steam in chemical plants. In this cycle, a throttle valve is provided between the condenser outlet and separator inlet to regulate the composition and mass flow ratio of mixture refrigerant in the two evaporators. The specific enthalpies of refrigerant at the low-temperature (LT) evaporator and medium-temperature (MT) evaporator inlet are respectively reduced via the evaporative condenser and separator, leading to an enhancement in cooling capacity. Energy, exergy, and economic (3E) analyses are conducted to compare the performance between the TEARC and the basic two-stage and dual-temperature ejector refrigeration cycle (BTERC). At the basic operating condition, the TEARC has enhancements of 9.13 % and 9.95 % in COP and exergy efficiency than those of the BTERC. According to the multi-objective optimization results, it indicates that the TEARC's COP, exergy efficiency, and levelized cost of cooling are respectively improved by 8.93 % and 5.67 % and reduced by 1.22 % compared to the BTERC at optimum operating conditions. The simulation results of the proposed cycle reveal a significant performance improvement and the potential for application in waste heat-driven refrigeration.

Bankruptcy Prediction and Performance: the Influence of Quality Certification on Portuguese SMEs

Objective: To observe the existence of a relationship between quality certification and performance and bankruptcy prediction for Portuguese SMEs. Theoretical Reference: The search for quality and its certification, via the International Standard Organization (ISO), theoretically, is related to the going concern assumption, making it possible to enhance the company's economic and financial sustainability. Method: Multisectoral Multivariate Discriminant Analysis (ADM) models, considered the most efficient, were selected for application, as well as the commonly used Univariate Analysis indicators. In Bureau Van Dijk's SABI Database, we collected Portuguese SMEs, with financial information from 2014 to 2018, certified in the scope of quality, ISO 9000 or 9001, on 12/31/2018, of these, we focused on those with main activity in NACE D - Electricity, Gas, Steam, Hot and Cold Water and Cold Air or G - Wholesale and Retail Trade, Repair of Motor Vehicles and Motorcycles as they are the most important. The Sector Average Company was also collected for the same NACE via Banco de Portugal Sector Tables. Then, having applied the models and indicators under study, we compared the results obtained between them, in order to observe the possible effect of quality certification on financial performance. Results and Discussion: No implication of quality certification in improving or optimizing the performance or economic-financial position of entities is identified. Implications of the Research: Uncover the influence of quality certification on the economic-financial position of companies, allowing for deeper investigation into bankruptcy, sustainability and value creation. Originality/Value: The specificities of the sectors and business size, crises and increasing closures make it vital to identify what will influence performance and sustainability, as no studies have been identified on this topic, focusing on Portuguese SMEs, certified via ISO 9000 or 9001.

Enhanced accident tolerance properties of AlCrCuFeMoNbx high entropy coating for nuclear fuel cladding

High entropy alloy AlCrCuFeMoNbx (x=0.5, 0.8, 1.4, 2.0) coatings were deposited on Zr-1Nb alloy substrates by magnetron co-sputtering to improve the accident tolerance capability of the nuclear fuel cladding. The structural and accidental tolerant properties of high-entropy alloy coatings have been investigated comprehensively. The results show that coatings with varying Nb contents exhibit amorphous structures. The hardness and elastic modulus of the coatings increase with the Nb content, reaching their maximum values at x = 2.0, which are 11.38GPa and 186.05GPa, respectively. In both the simulated normal operating and accident environment of the nuclear fuel cladding, the oxidation resistance of the coating has been investigated. The best oxidation resistance was achieved at x=0.8 in pure water at 360℃under 18.6MPa for 3 days. The dense Cr2O3 and CrNbO4 oxide films generated on the surface hinder the diffusion of oxygen ions, and account for the lower weight gain 5.10mg/dm2, decreased by 56.4% compared to that of the uncoated zirconium alloy. The coating with x=0.5 showed a drastic reduction in oxidized weight gain by 84.02% compared to the uncoated zirconium alloy in water steam at 1200℃, demonstrating excellent accident tolerance, which is due to the dense α-Al2O3 and CrNbO4 protective layer generated on the surface of the coating. These findings suggest that high entropy alloy coatings have promising accidental tolerance capabilities for nuclear fuel cladding.

Experimental investigation of the swirling steam jet condensation at low mass flux

Swirling steam jet condensation holds significant applications in industrial processes such as nuclear safety and gas–liquid mixing in the oxygen transmission pipeline of the liquid rocket engine. However, due to its involvement with complex flow and phase-change heat transfer, the application and optimization of related condensation technologies still face challenges. Therefore, this paper aims to investigate the condensation characteristics of the swirling steam jet by numerous experiments. The steam mass flux is 15–45 kg/(m2·s), and the water temperature ranges from 40 to 85 °C. A novel X-type swirl pressure nozzle is selected to achieve the swirling flow of the steam jet. A comparative analysis is conducted on the interface behavior and evolution of condensation parameters of the non-swirling and swirling steam jets during condensation processes. Results show that the swirling jet condensation includes three flow patterns, namely, chugging regime, smooth grown bubble regime, and rough grown bubble regime. Compared with the non-swirling steam jet condensation, swirling steam jets exhibit a 10.36% increase in the smooth grown bubble regime region and a 14.63% decrease in the rough grown bubble regime. Swirling bubble morphology evolves steadily, and the surface is smoother and more rounded. Simultaneously, irregular deformation behaviors can also occur in the swirling bubble condensation process, such as spiral growth of jet bulge, neck torsion, and the corolla pattern. This deformation helps to increase the contact area and prolongs the bubble lifetime, allowing for more adequate heat transfer at the steam–water interface. The swirling motion of the steam jet will reduce the bubble collapse frequency. As the water temperature rises from 60 to 80 °C, the bubble condensation rate and collapse frequency decrease. The bubble radius increases and the condensation time is extended. With the increasing steam mass flux, the collapse frequency gradually increases. The condensation rate and the bubble radius vary nonlinearly. At the higher steam mass flux, the swirling motion can effectively release the heat that accumulates inside the bubble after reaching the condensation equilibrium state.

Polyzwitterionic hydrogel using waste biomass as solar absorbent for efficient evaporation in high salinity brine

Solar-driven interfacial vapor generation (SVG) is a promising strategy for brine purification. However, the effective combination of functional evaporator backbones and solar absorbers for SVG enhancement remains challenging in high-salinity brines (≥10 wt%). Herein, a biomass-based polyzwitterionic hydrogel (PZH) was developed to improve the SVG performances in 10 wt% brine. Zwitterions with specific anti-polyelectrolyte effects served as backbones for accelerating H2O transportation, with fewer salt deposits and macropore channels. The biomass of straw prepared at a pyrolysis temperature at 600 ℃ was the most effective solar absorber. The synthesis of So600-PZH-8mm yielded the optimal solar evaporator with a low evaporation enthalpy of 877.79 J·g−1, a remarkable solar-to-vapor energy efficiency of 87.1 %, and a high evaporation rate of 3.57 kg·m−2·h−1 under 1 sun irradiation and a relative humidity of 30 %. Multi-cycle evaporation tests further verified the high quality of the steam water, high salt resistance, reliability, and durability of So600-PZH-8mm in practical applications. Furthermore, density functional theory calculations of the binding energies of charged groups and ions verified the anti-polyelectrolyte effect and swelling behavior of the PZHs. Overall, this study demonstrated the effectiveness of waste biomass as solar absorber for high-efficiency solar adsorption and water activation, which opens a new perspective to inspire the up-conversion of waste biomass in more valuable and meaningful ways.

Color Change of Pear Wood (Pyrus communis L.) during Water Steam Treatment

Hydrothermal treatment of wood, particularly steaming with saturated water steam, is often used to achieve a more intensive and homogenous wood color or to vary its hue. However, information on pear wood (Pyrus communis L.) steaming is limited in the available literature. This paper investigates the influence of steaming on the color of pear wood. Green, water-saturated samples of pear wood heartwood and sapwood were steamed with saturated water steam for 24 h at 98 °C. The color of the heartwood and sapwood was assessed both visually and with a standard three-stimulus colorimeter using the CIEL*a*b* system, and compared to the natural color of pear-wood. Additionally, FT-IR spectrometry was employed to analyze chemical changes in the wood samples. The results showed that both heartwood and sapwood experienced a decrease in lightening (L*), an increase in redness (a*), and a decrease in yellowness (b*) during steaming. Furthermore, a trend toward the equalization of L*, a*, and b* parameters between heartwood and sapwood over time was observed. FT-IR spectroscopy revealed that the chemical changes during steaming were primarily related to extractives and hemicelluloses, with no significant changes in cellulose and lignin. The obtained results suggest that pear wood color can be equalized to some extent by steaming and that the extent of the color change to darker tones is dependent on steaming time.

When cellulose nanocrystals meet graphene oxide: Structurally enhanced aerogels for efficient solar steam generation and water purification

Pollution, population growth, and climate change are intensifying global freshwater shortages. Traditional methods of collecting freshwater, such as rainwater harvesting and sewage treatment, have high energy consumption, limiting their implementation in underdeveloped regions. On the other hand, solar-driven seawater evaporation offers a promising solution, purifying water using naturally abundant solar energy. Reduced graphene oxide (rGO) is considered as a strong candidate for this purpose due to its broad spectral absorption. However, its hydrophobicity hinders its direct use in solar steam generators. Here, we report the preparation of a series of cellulose nanocrystal (CNC)-rGO aerogels (CGAs) through a one-pot hydrothermal gelation process, followed by unidirectional freeze-drying. The introduction of CNCs enhances the hydrophilicity and structural stability of the resulting CGAs. The CGAs also feature uniform and unidirectional channels that promote efficient water transport, as confirmed by scanning electron microscopy (SEM) and X-ray microtomography (XMT). The CGAs have an optimized water evaporation rate of 1.80 kg m−2 h−1 under 1 sun irradiation, with 90 % solar-to-vapor energy efficiency. Moreover, durability and seawater desalination tests provide additional evidence for the practicality of CGAs in water purification. It is anticipated the implementation of CGAs will expedite the application of solar steam generators in practical scenarios.

Interfacial solar‐driven steam and electricity co‐generation using Hydrangea‐like graphene by salt‐assisted carbonization of waste polylactic acid

AbstractThe interfacial solar steam generation and water evaporation–driven power generation are regarded as promising strategies to address energy crisis. However, it remains challenging to construct low‐cost evaporators for freshwater and electricity co‐generation. Herein, we report a salt‐assisted carbonization strategy of waste polylactic acid to prepare Hydrangea flower–like graphene and build a bi‐functional graphene‐based evaporator. The evaporator presents merits of good sunlight absorption, photo‐to‐thermal conversion property, water transport, good thermal management capability, and negatively charged pores for the continuous diffusion of ions. Hence, it achieves the evaporation rate of 3.0 kg m−2 h−1 and output voltage of 0.425 V, surpassing many advanced evaporators/generators. Molecular dynamics simulation result proves that more Na+ ions are attracted by functional groups, especially –COOH/C–OH, to promote Na+ selectivity in nanochannels. This work offers new opportunities to construct multifunctional evaporators for freshwater and electricity co‐generation.

Advanced Machine Learning Techniques for Energy Consumption Analysis and Optimization at UBC Campus: Correlations with Meteorological Variables

Energy consumption analysis has often faced challenges such as limited model accuracy and inadequate consideration of the complex interactions between energy usage and meteorological data. This study is presented as a solution to these challenges through a detailed analysis of energy consumption across UBC Campus buildings using a variety of machine learning models, including Neural Networks, Decision Trees, Random Forests, Gradient Boosting, AdaBoost, Linear Regression, Ridge Regression, Lasso Regression, Support Vector Regression, and K-Neighbors. The primary objective is to uncover the complex relationships between energy usage and meteorological data, addressing gaps in understanding how these variables impact consumption patterns in different campus buildings by considering factors such as seasons, hours of the day, and weather conditions. Significant interdependencies among electricity usage, hot water power, gas, and steam volume are revealed, highlighting the need for integrated energy management strategies. Strong negative correlations between Vancouver’s temperature and energy consumption metrics are identified, suggesting opportunities for energy savings through temperature-responsive strategies, especially during warmer periods. Among the regression models evaluated, deep neural networks are found to excel in capturing complex patterns and achieve high predictive accuracy. Valuable insights for improving energy efficiency and sustainability practices are offered, aiding informed decision-making for energy resource management in educational campuses and similar urban environments. Applying advanced machine learning techniques underscores the potential of data-driven energy optimization strategies. Future research could investigate causal relationships between energy consumption and external factors, assess the impact of specific operational interventions, and explore integrating renewable energy sources into the campus energy mix. UBC can advance sustainable energy management through these efforts and can serve as a model for other institutions that aim to reduce their environmental impact.

Distillation and gas stripping purification plants for the JUNO liquid scintillator

The optical and radiochemical purification of the scintillating liquid which will fill the detector of the JUNO experiment plays a crucial role in achieving its scientific goals. Given its gigantic mass and dimensions, and an unprecedented target value of about 3% at 1MeV in energy resolution, JUNO has set severe requirements on the parameters of its scintillator, such as attenuation length (Lat>20m at 430nm), light yield, and content of radioactive contaminants (238U,232Th<10-15g/g). To accomplish these needs, the scintillator will be processed using several purification methods, including distillation under vacuum and gas stripping, carried out in two large-scale plants installed at the JUNO site.In this paper, the layout, operating principles, and technical aspects which have driven the design and construction of the distillation and gas stripping plants are reviewed. The distillation is effective in enhancing the optical properties and removing high-boiling radioactive impurities (238U, 232Th, 40K), while the stripping process exploits pure water steam and high-purity nitrogen to extract gaseous contaminants (222Rn, 39Ar, 85Kr, O2) from the scintillator. The plant operating parameters have been tuned during the recent commissioning phase at the JUNO site and several quality control measurements and tests have been performed to evaluate the performances of the plants. Preliminary results on the efficiency of these purification processes will be shown.

Finite Element Analysis of the Pressure Vessels with Various Materials and Thicknesses

Pressure vessels are widely used in many areas. Ensuring the safe operation of pressure vessels is particularly important, especially in residential and industrial applications. Errors made during the use of pressure vessels or mistakes during manufacturing and design can lead to significant accidents, resulting in loss of life and property. With the increase in industrialization and energy production, significant advancements have been made in the field of pressure vessels. These vessels are used in various applications, such as heat exchangers in domestic heating systems, and in industrial facilities for the production of steam, superheated oil, and hot water needed for production and separation processes. The advancement of technology and the updating of design and computer aided design programs enable more accurate results in new design and analysis, allowing to produce more reliable and safer materials. To minimize occupational accidents, necessary precautions must be taken in advance. The development of pressure vessels in terms of occupational safety has been ongoing from past to present and is being further enhanced through ongoing studies. In our study, pressure and stress analysis were conducted using the finite element method on ANSYS. Mechanical analyses were repeated for three different thicknesses and three different material types. The purpose of the mechanical analysis was to examine the effect of the thicknesses and different material types on pressure vessels in terms of stress, deformation, and strain.

Off-design performance optimization for steam-water dual heat source ORC systems

High-pressure steam and hot water often coexist as industrial waste heat. In this study, dual loop and single loop ORC systems are designed for 700 kPa, 4.1 kg/s steam, and 90 ℃, 122.36 kg/s hot water conditions to study the off-design performance when steam or hot water conditions change. To maximize net output power, we employ a particle swarm optimization algorithm to optimize the evaporation and condensation temperatures. The results show that within the specified hot water conditions, the evaporation and condensation temperatures of D-ORC's low-pressure loop and S-ORC increase with rising hot water inlet temperature and flow rate. The S-ORC demonstrates a higher net output power growth rate as hot water flow rate and temperature rise. Under specific steam conditions, when the steam outlet is in a gas-liquid two-phase state, D-ORC's maximum net output power is 1.7 % higher than that of the S-ORC, with little variation in optimal evaporation and condensation temperatures with respect to steam inlet pressure. At a 3.5 kg/s steam flow rate, the D-ORC's high-pressure loop becomes ineffective, whereas S-ORC efficiently adjusts heat exchange capacity under diverse steam-water conditions, Consequently, the D-ORC's average net output power is 34.2 % lower than that of the S-ORC.

Techno-economic assessment of gasoline production from Fe-assisted lignocellulosic biomass hydrothermal liquefaction process with minimized waste stream

Techno-economic analyses were conducted on an iron-assisted hydrothermal liquefaction (HTL) process for converting lignocellulosic biomass into gasoline, comparing two approaches for minimizing by-product streams. The primary difference between the two approaches lies in their hydrogen (H₂) source for upgrading bio-crude to bio-gasoline. Scheme 1 utilizes residual water-soluble and gaseous compounds from the process to generate the H₂ needed for upgrading. Scheme 2, on the other hand, converts these waste streams into heat to supply part of the required energy, while external H₂ from steam methane reforming (with or without CO₂ capture) or water electrolysis (green hydrogen) is used for upgrading. Both schemes use pinewood and red mud as feedstocks. Red mud, after the reduction of Fe₂O3 to metallic iron, is employed in the HTL reactor as a hydrogen producer, enhancing both the yield and quality of the bio-crude while minimizing the H2 consumption in the upgrading unit. The HTL reactor was modeled based on optimal operating conditions experimentally determined while sensitivity analyses were performed on the other scheme’s units to determine their optimal conditions. A Life Cycle Assessment (LCA) was also conducted to measure the environmental impact of the two scenarios.Both schemes produce 459 tonnes of gasoline equivalent per day, consuming 33 tonnes of H2. Scheme 2 achieves a minimum fuel selling price (MFSP) of $0.94 per liter of gasoline equivalent (LGE), with methane reforming and CO₂ capture providing the lowest emissions (1.13 kg CO₂-Eq per kg of LGE). Scheme 1 has a slightly higher MFSP of $0.96 per LGE but is more environmentally sustainable, with a LCA showing 1.11 kg CO₂-Eq per kg of LGE.

Biomass-Derived Carbons as Friction Reducing Additives for Lubricants: Tribological Properties of Biochars and Activated Carbons Obtained from Sugar Cane Bagasse

Activated carbons are commonly used for adsorption/depollution applications, but only a few studies are related to their lubricating properties. In order to investigate a new family of friction reducers, the tribological properties of biochars and derived activated carbons obtained from sugar cane bagasse are investigated. Activated carbons are obtained from either a physical (steam water) or chemical (with phosphoric acid) activation process. The tribological tests show that the activated carbons present very low friction coefficients, close to 0.08. The correlation of textural and tribological investigations shows that the specific surface area of the compounds as well as the microporous and mesoporous domain extensions are key parameters to optimize the friction reduction properties of activated carbons. The friction properties of the compounds are improved if the mesoporous domain extension is above 40% of the total porous volume. This study shows that local biomass waste valorization is possible and that sugar cane bagasse-derived activated carbons appear as interesting new friction reduction additives for lubricants.

Оценка эффективности завихрения воздуха при распылении водоугольных суспензий пневматической форсункой

Due to modern requirements for environmental protection, introduction of environmentally friendly power engineering technologies involves search and development of new energy sources. One of the ways to meet these requirements and maintain the same level of energy production by thermal power plants is to use multicomponent fuels. The most promising and affordable heavy fuel oil from the point of view of energy, ecology and economy are coal-water slurries (CWS). In this regard, the study of the properties and characteristics of such fuels is relevant. The coal-water slurries have been prepared in a rotary hydrodynamic cavitation generator. A pneumatic atomizer with external mixing is used to spray the coal-water slurries. Interferometric Particle Imaging method is used to determine the average size of fuel droplets after atomization. The authors have conducted experimental studies of the characteristics of atomization of coal-water slurries based on lignite and pyrogenetic liquid with a pneumatic atomizer with a tangential supply of a spraying agent. A three-stage method to prepare lignite-based slurries with pyrogenetic liquid has been tested. It has been established that when using this technique, the fluidity of coal-water fuel is maintained even with the introduction of 20 % by weight of pyrogenetic liquid into the composition of coal-water slurries when replacing both water and coal in equal proportions. The kinematic viscosity of coal-water suspensions increases when pyrogenetic liquid is added, despite a decrease in the concentration of the solid component. The change of suspension density is insignificant. The results of the study of atomization process have shown that the tangential air supply to the atomizer leads to an increase of the jet spraying angle by 6° compared with direct supply. At the same time, the average droplet size in the jet of a two-component CWS with direct air supply is 8 % smaller. The results of the study have made it possible to obtain completely new knowledge that can significantly advance domestic and world science and technology in the field of power engineering, namely the technology of coal-water fuels atomization. Experimental studies have determined the main patterns of influence of the CWS properties and the method of spraying agent supply on the formation of a gas-drop jet. Such patterns will provide conditions for the effective atomization of quite viscous CWS in the combustion chambers of energy boilers. The results obtained will enable designers and constructors to develop highly efficient designs of steam and hot water boilers and gasifiers fueled by CWS.