High Heating Rates Research Articles

Ultrafast high‐temperature sintering of ZrB2

AbstractUltrafast high‐temperature sintering (UHS) is a joule heating method with an extremely high heating rate (∼103–104°C/min). In this work, commercial ZrB2 powders were rapidly densified by UHS to >90% relative density within 60 s in vacuum without pressure. Bulk density improved from 75% to 93% of relative density by increasing the sintering duration from 10 to 60 s. The final grain size increases from 2.7 ± 1.1 to 19.0 ± 8.4 μm when the sintering time increased from 10 to 60 s. X‐ray diffraction and energy‐dispersive spectroscopy show crystalline phase and compositional uniformity in ZrB2 after UHS.

Experimental study of interface behavior and sound pressure oscillation of direct contact condensation of a steam jet in flowing water

Direct contact condensation of a vapor jet in liquid is frequently encountered in lots of industrial applications because of its high heat and mass transfer rates. However, severe interface and sound pressure oscillation associated with condensation might cause vibration and even failure of pipeline systems. In this paper, the interface behavior and the sound pressure oscillation of a steam jet in flowing water are captured respectively by a high-speed camera and a high-frequency hydrophone. According to the gray profile of the image, an identification method is proposed to determine the interface characteristics, including the plume shape, width, and penetration length of the jet. The statistical intensity and power spectrum density of the interface position and sound pressure oscillation of the steam jet are calculated. Two typical condensation regimes of Chugging and Oscillation-I under low steam mass flux (Gs < 346 kg/m2s) are observed. The intensities of the interface oscillation and sound pressure oscillation decline with increasing steam mass flux and a significant correlation coefficient of about 0.94 between them is revealed. With the incorporation of sound pressure parameters, two correlations of the dimensionless jet length and its oscillation intensity are established, with relative deviations of 20% between the experimental and predicted values. For Oscillation-I, the dominant frequencies of the interface oscillation and sound pressure oscillation are quantitatively consistent. From the time and frequency domain perspectives, it is quantitatively confirmed that the sound pressure oscillation of the steam jet under low steam mass flux is caused by its interface oscillation.

The Kinetic Mechanism of the Thermal Decomposition Reaction of Small Particles of Limestone at Steelmaking Temperatures

Converter blowing limestone powder making slag steelmaking process has the advantages of low carbon and high efficiency, and can realize the resource utilization of CO2 in the metallurgical process, which is in line with the development direction of green metallurgy. Based on a thermogravimetric-differential thermal analyzer, the kinetic mechanism of decomposition of small limestone at steelmaking temperatures was investigated by a modified double extrapolation method. The results showed that with a higher rate of heating, limestone decomposition lagged, and decomposition temperature increased. Furthermore, the smaller the limestone particle size, the lower the activation energy of decomposition. Compared with N2, air, and O2, small limestone powder used for converter blowing could complete more rapid decomposition, and the time required for decomposition shortened by about 1/3, although the decomposition temperature increased in the CO2. The limestone decomposition rate increased and then decreased at low to high CO2 partial pressures. With a limiting link, the inhibition was more significant under high CO2 partial pressure, but the reaction can be fully completed by 1000 °C. The decomposition type modeled was stochastic nucleation and subsequent growth. As the partial pressure of CO2 increased from 25% to 100%, the number of reaction stages, n, increased.

Thermal Analysis Kinetics Study of Pulverized Coal Combustion under Oxygen-Rich Atmosphere.

The thermal analysis kinetic behavior of pulverized coal combustion in different oxygen-rich atmospheres is studied with a thermogravimetric (TG) analyzer. The effects of heating rate on combustion characteristic are considered. The results showed that the combustion rate of pulverized coal increased and the burnout time decreased under the conditions of an oxygen-enriched atmosphere and high heating rate. As the heating rate increases, the TG and derivative TG curves of the coal samples generally move toward the high-temperature region, and the thermal hysteresis phenomenon occurs. The changes in oxygen concentration and heating rate mainly affect the combustion stage of coal samples. The decrease in heating rate or the increase in oxygen concentration will cause a decrease in ignition point temperature and burnout temperature. Under the condition of 40% O2, the oxygen concentration and heating rate have the greatest influence on the combustion characteristic parameters. In addition, the combustion reaction of pulverized coal in the warming process was analyzed by FWO and KAS methods, respectively. The results showed that the changes in oxygen concentration and heating rate affected the activation energy, and the activation energy of coal samples increased with the increase in oxygen concentration.

Pyrolysis of Automotive Shredder Residue (ASR): Thermogravimetry, In-Situ Synchrotron IR and Gas-Phase IR of Polymeric Components.

This article reports the characterisation of pyrolysis of automotive shredder residue using in situ synchrotron IR, gas-phase IR, and thermal analyses to explore if the automotive shredder residue can be converted into value-added products. When heating to ~600 °C at different heating rates, thermal analyses suggested one- to two-stage pyrolysis. Transformations in the first stage, at lower temperatures, were attributed to the degradation of carbonyl, hydroxyl, or carboxyl functional stabilisers (aldehyde and ether impurities, additives, and stabilisers in the ASR). The second stage transformations, at higher temperatures, were attributed to the thermal degradation of the polymer char. Simultaneous thermal analyses and gas-phase IR spectroscopy confirmed the evolution of the gases (alkanes (CH4), CO2, and moisture). The synchrotron IR data have demonstrated that a high heating rate (such as 150 °C/min) results in an incomplete conversion of ASRs unless sufficient time is provided. The thermogravimetry data fit the linearised multistage kinetic model at different heating rates. The activation energy of reactions varied between 24.98 and 124.94 kJ/mol, indicating a surface-controlled reaction exhibiting high activation energy during the initial stages and a diffusion and mass transfer control showing lower activation energy at the final stages. The corresponding frequency factors were in the range of 3.34 × 1013-5.68 × 101 mg-1/min for different pyrolysis stages. The evolution of the functional groups decreased with an increase in the heating rate.

A Facile Aerobic Calcination Synthesis of Porous Oxygen‐Doped g‐C3N4 with High Adsorption Performance and Efficient Photocatalytic Activity

AbstractIn this study, porous oxygen‐doped graphitic carbon nitride (g‐C3N4) was successfully prepared via a facile aerobic calcination method using urea as the precursor. By adjusting the heating rate, the micro structural and the optical properties of this material were investigated. A series of characterizations indicate that the low heating rate is conducive to obtaining the g‐C3N4 possessing layered porous structure and large specific surface area. Meanwhile, it was found that narrower band gap (2.48 eV) and more effective carriers separation efficiency (2.54 ns) can be achieved by introducing oxygen dopants into the g‐C3N4, which is beneficial to the improvement of the photocatalytic performance. Additionally, the methylene blue (MB) wastewater degradation experiment was explored by using the porous oxygen‐doped g‐C3N4. It was demonstrated that the g‐C3N4 synthesized at low heating rate shows superior efficiency (99.1 %) for MB wastewater degradation treatment than the one synthesized at high heating rate (92.6 %). Thus, the porous oxygen‐doped g‐C3N4 obtains at low heating rate by aerobic calcination approach exhibits superior efficiency for dyeing wastewater treatment.

Latent Thermal Energy Storage for Solar Industrial Drying Applications

Solar heat is an attractive alternative in industrial processes. However, the intermittent and stochastic nature of solar energy necessitates the use of heat storage systems to bridge the gap between heat production and demand. This study introduces a validated numerical analysis approach to investigate the performance of latent storage tanks filled with spherical phase-change materials. A 1D thermal model is developed to describe the charging processes of adipic acid as PCM. The study examines the performance characteristics of latent heat storage in terms of stored energy and duration through parametric investigations. For mass flow rates ranging from 600 to 1000 kg/h, storage durations were found to vary from 440 to 582 min. The storage duration decreased significantly from approximately 1150 min at a charging temperature of 160 °C to 470 min at a charging temperature of 240 °C. The bed porosity affected the storage process, with a porosity of 0.5 achieving a thermal energy storage of around 344 MJ but requiring a longer charging time of about 610 min. Higher heating rates allowed for lower storage durations, with storage durations of approximately 460 min for a heating rate of 3 °C/min, compared to 660 min, for a heating rate of 0.5 °C/min.

Experimental study on thermo-mechanical behaviour of beam string structures

Beam string structures (BSS) have been widely employed in large-span spatial structures, while the experimental study on BSS in fire conditions is limited. This paper presents experimental investigation on thermo-mechanical behaviour of BSS with different load ratio. ISO834 standard fire and large space fire are adopted as fire conditions, respectively. The strain of BSS at high temperatures is measured by advanced strain gauges. The test results show that the prestressed string is the most vulnerable component of BSS in fire. The temperature distribution is non-uniform, and the temperature difference between the top flag and string can be up to 396.3 °C. The critical string temperature is in a range of approximate 350 °C–450 °C. Load ratio has little effect on the critical string temperature, and fire conditions with higher heating rate can increase the critical string temperature. Furthermore, the drop of residual prestress causes the rapid increase of mid-span vertical displacement and horizontal displacement. The direction of horizontal displacement of BSS without external load is outward, due to the thermal expansion. The strain distribution along the cross section indicates the additional bending moment induced by temperature. In addition, three behaviour modes of BSS at elevated temperatures are proposed according to the contribution of prestress. The behaviour modes illustrate the working mechanism of BSS as the temperature increases. Finally, a thermo-mechanical finite element model of BSS in fire conditions is established by assembly load method. The numerically predicted temperature distribution, displacement and residual prestress have a good agreement with the experimental results.

Microstructure characterization of electric field assisted sintering (EFAS) sintered metallic and ceramic materials using local thermal diffusivity measurement

Electric Field Assisted Sintering (EFAS, also referred to as spark plasma sintering) is a powerful technology for the consolidation of powder materials. The high heating rate during the sintering process is critical for minimizing energy consumption, but it can also cause microstructure heterogeneities in sintered parts, such as spatially varied porosity. The examination of localized porosity usually requires the use of a scanning electron microscope with a carefully prepared surface. In this paper, photothermal radiometry is used to measure local thermal diffusivity and extract localized porosity of EFAS-sintered parts by using a percolation-threshold model. Applying this approach, we identified the radial position-dependent porosity variation in EFAS parts, which is likely formed due to the large temperature gradient during the sintering process. This approach has a unique advantage because it can measure samples with minimal or no surface preparation, enabling the possibility of in situ characterization in EFAS with proper system modification. Necessary modifications on the measurement approach for EFAS deployment and in situ characterization are also discussed.

Effects of material combination for ultrasonic spot welding on microstructure and strength of Al/Al, Al/Cu, and Al/Ni dissimilar joints

The dissimilar joining of Al/Cu and Al/Ni is required to reduce the weight of electronic and electrical devices. Ultrasonic spot welding (USW) is expected to be applied to dissimilar materials because of the low heat input during the joining process. However, to obtain high strength via USW, the relationship among the welding parameters, joining strength, and microstructure for different material combinations must be investigated. In this study, Al/Al, Al/Cu, and Al/Ni are joined via USW by systematically varying the welding parameters; subsequently, their tensile shear load and microstructure are investigated. Results show that the vibration amplitude and welding time impose greater effects on the joint strength than the welding pressure for all material combinations. High-strength joints that fractured at the Al upper plate are obtained by optimizing the welding parameters for each material combination. Al/Ni bonding had a narrower margin of welding time to obtain a higher tensile shear load compared with other material combinations. This is due to the high heating rate and maximum temperature of Al/Ni joints, which cause the excessive deformation of the Al upper plate during prolonged welding. Texture analysis showed that recrystallized grains with GOSS orientation was remained in the high-strength dissimilar joints.

Modified network kinetic model for coal pyrolysis with high-value products and low carbon emissions

Pyrolysis is a clean and efficient technology for the conversion of low-rank coal. Its key product is tar with high value. The complex composition of tar limits its further effective utilization. Although most kinetic models can provide the final distribution of three-phase products in coal pyrolysis, an effective prediction method for the specific composition of tar and gas has not yet been developed. Most numerical models serve to improve the total yield of volatile matter and cannot provide theoretical guidance for the improvement of tar quality or the reduction of carbon emission. Based on the basic assumptions of the CPD (Chemical Percolation Devolatilization) model for product molecules structure and generation mechanism, this paper proposed a more sophisticated method for dividing tar composition, which can achieve the division of light, medium, and heavy fractions of tar components according to boiling point. Light gas composition could be obtained with the combination of FG(Functional Group) submodel. The influence of pyrolysis final temperature, heating rate, and environmental pressure was explored for the yield and distribution of products of 18 coals. The simulation results showed that the total yield of tar was affected by both coal structure characteristics and operating parameters. Under conditions favorable for evaporation, such as low pressure and high temperature, the total yield of tar was positively correlated with the average aromatic core size in coal. Under other conditions, tar release was limited by its volatility. Coal with larger average aromatic core size corresponded to less tar yield instead. The pressure in the operating parameters had the most significant influence on the total yield of tar. The heavy fractions of tar are more sensitive to changes in operational parameters, making working conditions that increase the total yield of tar reduce tar quality. The overall carbon emission of pyrolysis is <1 kg CO2/kg tar, which is far lower than the 2–4 kg CO2/kg tar and 3–9 kg CO2/kg tar of direct and indirect liquefaction processes. Under the conditions of sufficient insulation time and no consideration of secondary reactions, the carbon emission of pyrolysis only depended on the content of carboxyl groups in the precursor functional groups. Therefore, the carbon emission intensity decreased with the increase of coal rank. For the optimization for total tar yield and tar quality, 1 atm pressure and 723–923 K temperature was optimal for low rank coals, while low temperature and heating rate with 10–20 atm pressure or high temperature and heating rate with 45–50 atm pressure were optimal for medium rank coals. For the optimization of light tar yield and tar quality, 6–9 atm pressure was optimal for low-rank coals, and 1–3 atm pressure was optimal for medium-rank coals.

Liquefaction Controlling Components and Their Effect on Carbon-Free Mold Powders

In the continuous casting of ultra-low carbon steels, recarburization from the mold powder negatively affects steel quality. Therefore, to develop mold powders without free carbon, different carbides or nitrides have been proposed and evaluated in laboratory and field studies. Among these, SiC and Si3N4 were selected for the present study. Additionally, thermodynamic calculations were performed to quantitatively describe their effect on the melting behavior of the mold powder. To verify the results under high heating rates, mixtures of raw material components were placed in a steel crucible with a lid, inserted into a furnace preheated to different temperatures, and investigated mineralogically. The results agreed with those of the thermodynamic calculations. Moreover, the results suggested that Si3N4 and SiC were suitable raw material components and alternatives to carbon in the mold powder. They prevented solid–solid reactions between raw material components to form new phases and were still found at the temperature of 1200 °C. Consequently, the CaO/SiO2 ratio was higher before oxidation and affected the liquid-phase formation. The addition of antioxidants reduced the liquefaction-controlling effect of SiC. Additionally, the study shows that the sample preparation impacts the phase formation: granules facilitate phase formation due to a higher contact of reactants, further they show earlier melting close to their surface as sodium content is increased there by the spray drying procedure.

Rapid Fabrication of Metal-Nitrogen Doped Ordered Large-Pore Mesoporous Carbons Using Bottle Brush Block Copolymer Templates for Highly Efficient Water Oxidation

We describe a simple and fast method to fabricate ordered mesoporous carbon materials for electrocatalyst applications. Over the past decades, mesoporous carbons have been widely applied for photonics, energy storage devices, separation technologies, and electrocatalyst applications.1 These materials can be inexpensively prepared and have good electrical conductivity and chemical and mechanical stability. Linear block copolymer templates or polystyrene beads are widely used to create porosity in carbon materials. However, the existing methods have limitations in accessing a wide range of pore dimensions and porosities. Recently bottlebrush block copolymer (BBCP) templates have drawn significant attention for producing ordered carbon materials with ordered pores with tunable diameters ranging from 15 to 100 nm, which facilitates ion diffusion and mass transport during the electrochemical processes while maintaining high surface area.2 BBCP-derived large-pore mesoporous carbons are potential candidates for electrocatalyst applications. While water splitting produces hydrogen gas, oxygen gas simultaneously evolves via an oxygen evolution reaction (OER) or water oxidation.3 In OER, oxygen-oxygen bond formation involves a complicated proton-coupled mechanism. For this reason, most OER electrocatalysts require a high overpotential to overcome the sluggish kinetic energy barrier to generate oxygen gas during water oxidation, which is often associated with high costs and poor availability.4 Hence, developing a low-cost, highly efficient OER catalyst is necessary to lower the overpotential.Herein, we demonstrate efficient metal-nitrogen-doped mesoporous carbon materials using a simple and fast rapid thermal annealing (RTA) process. BBCP/precursor self-assembly, carbonization and template removal using the RTA process (high heating rate up to 100 °C / sec) occurred within a few minutes. The resulting electrocatalysts were characterized by small-angle X-ray scattering (SAXS), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. We used nickel foam as a support under basic conditions for electrochemical evaluation. The results showed ample catalytic active sites and an overpotential of <260 mV along with a low Tafel value of 55 mV/decade at a current density of 10 mA/cm2. Our findings can have significant implications for designing various metal-doped mesoporous carbon materials for energy and environmental applications, specifically metal-air batteries and CO2 reduction. References H.-F. Fei, W. Li, S. Nuguri, H.-J. Yu, B. M. Yavitt, W. Fan and J. J. Watkins, Chemistry of Materials, 32, 6055 (2020).H.-F. Fei, B. M. Yavitt, S. Nuguri, Y.-G. Yu and J. J. Watkins, Macromolecules, 54, 10943 (2021).D. Saha, V. Patel, P. R. Selvaganapathy and P. Kruse, Nanoscale Advances, 4, 125 (2022).H. Zhou, F. Yu, J. Sun, R. He, S. Chen, C.-W. Chu and Z. Ren, Proceedings of the National Academy of Sciences, 114, 5607 (2017).

Flash Pyrolyzed Coal Char for Sodium Ion Battery Anodes

Present day lithium ion batteries face challenges regarding the sustainability, cost, and natural resource availability of their components. Sodium has been shown to be a complementary energy storage material, providing usable volumetric energy density. In designing sodium ion batteries (SIBs), hard carbon is used at the anode in place of graphite, due to the necessary micro domain structure needed to store sodium ions. Coal char is a low cost material and viable source of hard carbon. The use of coal char in SIBs also provides a high value, secondary use pathway for the abundant char component of coal.In this work, flash pyrolyzation is explored as a novel approach for coal char synthesis for SIB anodes using a Utah local bituminous coal. During flash pyrolyzation, char is heated in a drop-tube furnace at 1000 oC/s vs. the traditional slow pyrolyzation approach where char is heated at 20 oC/min. Flash pyrolyzed (FP) char has a surface structure that is vastly different in comparison to the slow pyrolyzed (SP) char (Figure 1.), larger d-spacing (FP d-spacing = 0.379 nm, SP d-spacing = 0.364 nm) and a smaller closed micropore diameter (FP micropore = 1.52 nm, SP micropore = 1.91 nm), as concluded from X-ray diffraction (XRD) and small angle X-ray scattering (SAXS) analysis, respectively.The SIB performance of FP char vs. SP char is tested and compared in ether-based and ester-based electrolytes. FP char performs better as a SIB anode than SP char in both electrolytes. Additionally, both char anodes achieve higher reversible capacity and better initial coulombic efficiencies (ICE) in an ether-based vs. ester-based electrolyte. When FP char is combined with an ether-based electrolyte, a 10th cycle reversible capacity of 109.4 mAh/g is achieved, whereas a SP char with an ester-based electrolyte cell has a 10th cycle reversible capacity of 72.5 mAh/g, when both cells are cycled at 50 mA/g (sodium metal half-cells). FP ether cells also perform with an initial coulombic efficiency (ICE) of 64%, but SP ester cells only show an ICE value of 52%. The enhanced electrochemical performance of the FP cells is attributed to differences in surface/bulk structure due to the high heating rate. The improvement in char anode performance in ether-based cells is likely due to the formation of a thinner solid-electrolyte interphase and/or improved sodiation due to an ether-based electrolyte. Figure 1

Spark plasma sintering of ceramic-reinforced binary/ternary nickel and titanium metal matrix composites: Mechanical properties, microstructure, and densification – A review

Spark Plasma sintering is an excellent technique for developing ceramic-reinforced binary/ternary nickel and titanium metal matrix composites (MMCs). This review analyzes the mechanical properties, microstructure, and densification characteristics of SPS-produced composites. Introducing ceramic reinforcement such as carbides, oxides, nitrides, or borides enhances the mechanical characteristics and functionality of MMCs. The SPS method has advantages such as high heating rates, low processing durations, and relatively low sintering temperatures, all of which assist in reducing reactivity concerns and retaining the desirable properties of the matrix and reinforcing materials. The impact of different process parameters such as temperature, pressure, heating rate, and holding time on the final microstructure and densification of the composites was discussed in this review. Additionally, it examined how different types, contents, and particle sizes of reinforcement affected the mechanical qualities, including hardness, tensile strength, fracture toughness, and wear resistance. Furthermore, the production of secondary phases and the interfacial bonding between the matrix and reinforcements are explored because they significantly affect the mechanical performance and behavior of the composites. This work contributes to an extensive understanding of the SPS procedure for ceramic-reinforced nickel and titanium MMCs, offering insightful information on processing parameters that enhance production and modify the characteristics of these technologically advanced materials for many applications in the aerospace, automotive, and structural industries.

Flash spark plasma sintering of 3YSZ: Introducing structural and microstructural heterogeneity by high heating rates

Yttria stabilized zirconia (3 mol% YSZ) ceramics were prepared by Flash-SPS at various temperatures ranging from 700° to 2060°C using heating rates ⁓11,000 °C/min, and leading to densification in seconds. The influence of peak temperature on microstructure is then analyzed and displays unusual sintering trajectory. Densification shows a maximum of 91 % around 1600 °C and further decreases with increasing sintering temperature. The structural and microstructural homogeneities are assessed, showing the presence of remaining monoclinic phase from starting powder in the core of the pellets, even after sintering at 2060 °C, suggesting strong thermal gradient. This also results in grain size and morphology heterogeneity. This work aims at showing the importance of assessing homogeneity over the whole sample volume, especially for ultra-rapid sintering techniques.

Hydrogen production by kraft black liquor supercritical water gasification: Reaction pathway and kinetic

Kraft black liquor (KBL) supercritical water gasification (SCWG) has significant implications for carbon emission reduction and energy efficiency improvement in the pulp industry. This research focuses on investigating the SCWG of KBL under different reaction conditions, including reaction times (5–30 min), temperatures (450–650 °C), and feed concentrations (5%–20%), utilizing a high heating rate batch reactor. The performance of the gasification process is evaluated by analyzing gaseous, liquid, and solid products. Remarkable achievements in carbon gasification efficiency (CGE) of 95.28% and COD removal of 99.90% are attained at 650 °C, 30 min, and 10 wt% feed concentration. The liquid-phase products primarily comprise aromatic compounds, particularly phenolics, with the possible presence of reactive nonaromatic compounds such as cyclopentanone. Lower temperatures favor the formation of solid products, which result from phenolic agglomeration reactions leading to char formation. The research also explores the SCWG reaction pathway of KBL and develops a comprehensive twelve-lumped quantitative kinetic model. This work provides valuable engineering parameters for reactor design, optimization, and numerical simulations, facilitating advancements in SCWG of KBL technology.

Ultrafast crystallization and sintering of Li1.3Al0.3Ti1.7(PO4)3 glass through flash sinter‐crystallization

AbstractFlash sinter‐crystallization (FSC) is a new technique for concurrently crystallizing and sintering glasses, derived from flash sintering. In this study, we explore, for the first time, the use of FSC as a processing method for producing Li1.3Al0.3Ti1.7(PO4)3 (LATP) glass ceramics. Using FSC, LATP with NaSICON structure is produced at a furnace temperature as low as 460°C and a processing time of 5 min. The FSC‐processed samples with different current density limits were compared with those conventionally sinter‐crystallized (CSC) at 950°C for 1 h. We show that FSC can significantly improve the densification of LATP glass ceramics due to the volumetric high heating rate. Furthermore, the LATP samples processed by FSC exhibit superior total ionic conductivity than those processed by CSC, also surpassing the reported results for LATP with similar levels of densification. Therefore, our results suggest that FSC is a promising method for processing glass ceramics, particularly for materials with high crystallization kinetics like LATP, opening up new possibilities for the production of solid electrolytes.

EFEK LAJU PEMANASAN (HEATING RATE) TERHADAP DISTRIBUSI TEMPERATUR DAN KINERJA MODUL THERMOELECTRIC GENERATOR SP1848 SA

Thermoelectric Generator (TEG) is an energy conversion technology that converts heat energy into electrical. There are several factors that affect the performance of TEG, one of which is the heat source. This research will investigate the use of waste heat by varying the heating rate on the performance of TEG in generating electricity and the temperature distribution profile through experimental studies on a laboratory scale. The heating plate is used to heat the hot surface of the TEG. There are three variations of the heating rate used, namely: Low (0.355°C/min), Middle (0.933 °C/min) and High (1.558 °C/min). Temperature measurements were carried out on the hot surface (Th), the cold surface (Tc) of the TEG module, and the ambient temperature (Ta) using Arduino temperature data logger. Meanwhile, to measure the electrical output in the form of voltage (V) generated by the TEG module, using the Arduino voltage data logger. The results show when the heating rate used is high (high heating rate) then the average electrical output of the TEG module produces a voltage of 5.34V. The heating rate on the hot surface of the TEG module will affect the difference in surface temperature and the performance of the TEG module in generating electricity.

Tailored monolithic catalyst and reactor by direct photo-curing 3D printing for oxidative desulfurization of fuels

Structured monolithic catalysts have attracted growing attention in the petrochemical industry due to significant advantages of reusability, easy scale-up, and high heat and mass transfer rate. 3D printing offers enormous flexibility in accurately regulating the configuration of monolithic catalysts to realize the strengthening of the reaction process. However, this remains challenging in terms of reliable manufacturing, high resolution, and the distribution of active sites. Here, we report a direct photo-curing 3D printing based method for manufacturing precise monolithic catalysts for oxidative desulfurization of fuels. Numerous molybdenum oxide nanoparticles with a high density of oxygen vacancies are spatially distributed in three-dimensional Al2O3 by 3D printing technology and post-treatment, thus favoring the catalytic reaction. This 3D-MoOx/Al2O3 exhibits excellent catalytic performance with a 99.2 % conversion of dibenzothiophene. Furthermore, this tailored catalyst is 3D-printed to manufacture a monolithic agitating impeller as a stirring reactor, which plays a dual role in mixing and catalysis. The study provides an effective strategy for precisely manufacturing structured catalysts with excellent catalytic activity and can be readily applied to a range of chemical reactions.