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In order to reduce the environmental impact of conventional sludge treatment methods and to utilize the energy in sludge more effectively, a coupled system based on sewage sludge gasifier (SSG), solid oxide fuel cells (SOFC), supercritical CO2 cycle (S-CO2), and organic Rankine cycle (ORC) is proposed. The clean syngas obtained from sludge gasification is mixed with CH4 and then first utilized by the fuel cell. The exhaust gas from the fuel cell is fully combusted in the afterburning chamber and then enters the bottom cycle system consisting of S-CO2 & ORC to generate electricity. To understand the performance of the system, thermodynamic and economic analyses were conducted to examine the project's performance. The thermodynamics as well as the economics of the coupled system were analyzed to arrive at the following conclusions, the power production of the system is 37.34 MW; the exergy efficiency is 55.62%, and the net electrical efficiency is 61.48%. The main exergy destruction is the gasifier and SOFC, accounting for 62.45% of the total exergy destruction. It takes only 6.13 years to repay the construction investment in the novel system, and the project obtains a NPV of 17 723 820 USD during 20 years lifetime. The above findings indicate that the new coupled system has a better performance in terms of energy utilization and economy. [ABSTRACT FROM AUTHOR]

Efficient internal mixing stands as a pivotal requirement for droplet-based micro-reactors/micro-mixers facilitated by microfluidic systems. Among the various methods for their production, capillary-generated droplets emerge as a notable approach. Understanding the role of coaxiality within coflow microfluidic devices in influencing internal mixing remains a crucial aspect for optimizing these systems. Coaxiality within inserted cylindrical capillaries significantly affects mixing efficiency according to our experimental observations. Through numerical simulations, the intricate mixing dynamics of reagents inside droplet generated via a coflow capillary microfluidic system has been investigated. We demonstrate that coaxiality profoundly impacts the initial distribution of disperse phases within droplets, shaping subsequent internal mixing dynamics. Contrary to previous assumptions, our findings highlight the substantial impact of marginal deviations in coaxiality, around 20%, on optimizing mixing efficiency. This challenges prior beliefs and emphasizes the nuanced role of coaxiality in microfluidic systems. These insights advance our understanding of coaxiality's critical influence on enhancing mixing efficiency within coflow microfluidic devices, paving the way for improved design strategies and applications in diverse scientific fields. [ABSTRACT FROM AUTHOR]

The resistance of a large Pure Car Truck Carrier (PCTC) with a bulbous bow and a transom stern is evaluated in the present paper. Several cases at nine different ship speeds in calm water are simulated and results are compared with the experimental measurements. The maximum relative error is 0.93% at a Froude number (Fr) of 0.209. The total resistance coefficient of the ship in calm water shows a parabolic trend with increasing Fr, and it reaches a minimum value at Fr = 0.1794. Furthermore, the cases of the ship in regular waves with six different wavelengths and three wave heights are simulated. It is observed that the total resistance exhibits a quadratic relationship with the wavelength when the wave height is fixed. The wave-making resistance increases with the increase in wave height at any fixed wavelength, and it reaches a maximum value when the wave-length is 1.2 times the ship length (Lpp). Additionally, we also investigated the resistance in three different sea states at four different speeds. When the significant wave height of irregular waves is the same as regular waves, the wave-making resistance under irregular waves is much smaller than that of the regular waves. All of these results indicate that the bulbous bow and transom stern can reduce the wave-making and residuary resistances, which can provide a useful reference for the subsequent design and manufacturing of related ships. [ABSTRACT FROM AUTHOR]

Chlorine species, widely presented in industrial flue gas such as the waste incineration plants, can poison the catalysts and affect the selective catalytic reduction (SCR) performance. In this work, effects of Cl on the SCR performance of V2O5–WO3/TiO2 (VW/Ti) catalysts were investigated by NH4Cl deposition. The results showed that the NOx conversion efficiency at low reaction temperature (< 300 °C) decreased with the loading of NH4Cl after calcination. It was found that instead of causing the chlorination of VW/Ti catalyst the NH4Cl decomposed into volatile Cl species due to the weak V–Cl bonding. Such decomposition reduced significantly the surface non-lattice oxygen species to inhibit NO adsorption and activation, but hardly affected the redox ability and acidity of VW/Ti catalyst. Time–resolved in situ DRIFTs results indicated that NH3 activation and the SCR process predominated by Eley–Rideal mechanism were not influenced with NH4Cl impregnation, while the SCR at low temperature following a Langmuir–Hinshelwood path was limited by the decreased and weaker binding sites for NO activation. [ABSTRACT FROM AUTHOR]

Selective catalytic reduction of NOx by ammonia (NH3‐SCR) was affected by HCl, which was widely present in industrial flue gas. In this study, the SCR performances over MOx‐WO3/TiO2 (MW/Ti, M=Mn, Ce and V) catalysts after HCl treatment were investigated. It was found that HCl poisoning showed inhibition and promotion in NOx conversion over MnW/Ti and CeW/Ti catalysts, respectively. While the SCR activity over VW/Ti catalyst was hardly affected by HCl. Over MnW/Ti catalyst, the rupture of the Mn−O bond by the strong Mn−Cl binding induced the formation of amorphous MnCl2 species. This Cl‐containing species with Mn in a low oxidation state exhibited poorer redox ability and NO activation, resulting in a decrease in low‐temperature SCR activity. However, instead of directly affecting the CeOx and VOx sites, gaseous HCl reacted with NH3 to form NH4Cl species on the surface of CeW/Ti and VW/Ti catalysts. As a result, the SCR activity of VW/Ti catalyst was scarcely influenced by HCl, taking the unchanged redox ability and NH3 adsorption. With a further accumulation of NH4Cl on CeW/Ti catalyst, the NOx conversion at low temperature was evidently enhanced due to the promotion in NO‐to‐NO2 conversion (Fast‐SCR). [ABSTRACT FROM AUTHOR]

Selective catalytic reduction of NOx by ammonia (NH3‐SCR) was affected by HCl, which was widely present in industrial flue gas. In this study, the SCR performances over MOx‐WO3/TiO2 (MW/Ti, M=Mn, Ce and V) catalysts after HCl treatment were investigated. It was found that HCl poisoning showed inhibition and promotion in NOx conversion over MnW/Ti and CeW/Ti catalysts, respectively. While the SCR activity over VW/Ti catalyst was hardly affected by HCl. Over MnW/Ti catalyst, the rupture of the Mn−O bond by the strong Mn−Cl binding induced the formation of amorphous MnCl2 species. This Cl‐containing species with Mn in a low oxidation state exhibited poorer redox ability and NO activation, resulting in a decrease in low‐temperature SCR activity. However, instead of directly affecting the CeOx and VOx sites, gaseous HCl reacted with NH3 to form NH4Cl species on the surface of CeW/Ti and VW/Ti catalysts. As a result, the SCR activity of VW/Ti catalyst was scarcely influenced by HCl, taking the unchanged redox ability and NH3 adsorption. With a further accumulation of NH4Cl on CeW/Ti catalyst, the NOx conversion at low temperature was evidently enhanced due to the promotion in NO‐to‐NO2 conversion (Fast‐SCR). [ABSTRACT FROM AUTHOR]

Selective catalytic reduction of nitrogen oxides (NOx) with C3H6 (C3H6‐SCR) was investigated over NiO catalysts supported on different metal‐oxides. A NiAlOx mixed oxide phase was formed over NiO/γ‐Al2O3 catalyst, inducing an immediate interaction between NiOx and AlOx species. Such interaction resulted in a charge transfer from Ni to Al site and the formation of Ni species in high oxidation state. In comparison to other NiO‐loaded catalysts, NiO/γ‐Al2O3 catalyst exhibited the highest NOx conversion at temperature higher than 450 °C, but a poor C3H6 oxidation activity due to the decreased nucleophilicity for surface oxygen species. By temperature‐programed NO oxidation, it is indicated that nitrate species were rapidly formed and stably maintained at high temperature over NiO/γ‐Al2O3 catalyst. In situ transient reactions further verified the Langmuir–Hinshelwood mechanism for C3H6‐SCR, where both gaseous NO and C3H6 were adsorbed and activated on catalyst surface and reacted to generate N2. Due to the strong metal‐support interaction over NiO/γ‐Al2O3 catalyst, both nitrate and CxHyOz intermediates were well preserved to attain high C3H6‐SCR activity. [ABSTRACT FROM AUTHOR]

Selective catalytic reduction of nitrogen oxides (NOx) with C3H6 (C3H6‐SCR) was investigated over NiO catalysts supported on different metal‐oxides. A NiAlOx mixed oxide phase was formed over NiO/γ‐Al2O3 catalyst, inducing an immediate interaction between NiOx and AlOx species. Such interaction resulted in a charge transfer from Ni to Al site and the formation of Ni species in high oxidation state. In comparison to other NiO‐loaded catalysts, NiO/γ‐Al2O3 catalyst exhibited the highest NOx conversion at temperature higher than 450 °C, but a poor C3H6 oxidation activity due to the decreased nucleophilicity for surface oxygen species. By temperature‐programed NO oxidation, it is indicated that nitrate species were rapidly formed and stably maintained at high temperature over NiO/γ‐Al2O3 catalyst. In situ transient reactions further verified the Langmuir–Hinshelwood mechanism for C3H6‐SCR, where both gaseous NO and C3H6 were adsorbed and activated on catalyst surface and reacted to generate N2. Due to the strong metal‐support interaction over NiO/γ‐Al2O3 catalyst, both nitrate and CxHyOz intermediates were well preserved to attain high C3H6‐SCR activity. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hierarchically devised NiFeO x H y catalyst showed high OER activity under alkaline condition. • NiFeO x H y /Ni heterostructure was in-situ formed via a surface reconstruction process. • Charge transfer at the catalyst-electrolyte interface was improved with Fe incorporation into Ni (oxy)hydroxide. • Fe species located at the outer surface of NiOOH structure served as the OER active site. Nickel iron (oxy)hydroxide (NiFeO x H y) is among the most active electrocatalysts for oxygen evolution reaction (OER) in the alkaline media. Development of new design strategy for NiFeO x H y electrode with respect to intrinsic activity and number of active species is highly attractive. Here we report a hierarchical fabrication for NiFeO x H y electrode towards efficient oxygen evolution. Three-dimensional mesoporous NiO was initially prepared and reduced to a polycrystalline Ni metal framework. Despite the poor OER activity for Ni-based catalyst, the incorporation of surface Fe species induced a notably high current density for the oxygen evolution. The results indicated that the Fe species, located at outer surface region, played a key role as the OER active sites. It is also found that the surface of metallic Ni was reconstructed to (oxy)hydroxide phase with ease compared to NiO. As a result, a heterostructure composed of an OER-active NiFe (oxy)hydroxide shell and an electron-conductive Ni core was formed. In this fabricated NiFeO x H y /Ni catalyst, the promoted intrinsic activity, number of active sites and charge-transfer ability all taken into account contribute to an efficient OER process. [ABSTRACT FROM AUTHOR]

Development of new groups of oxygen evolution reaction (OER) electrocatalysts based on transitional metal materials is highly attractive for renewable energy conversion and storage. Here we report a new FeNb (oxy)hydroxide catalyst, which delivered a high OER activity with an overpotential as low as 0.34 V (at 10 mA cm−2). To attain a homogeneous mixing of metal components, niobium was initially incorporated into the framework of iron oxalate dihydrate. The mixed oxalate could be structurally transformed into short-range ordered (oxy)hydroxide, the reactive species for the OER. Incorporation of Nb has been demonstrated to improve the intrinsic OER activity based on Fe species and to accelerate the charge-transfer kinetics across the solid-electrolyte interface. It is also found that strong Fe–Nb interaction can induce the formation of high-valent Fe species. Theoretical calculation results further illustrate the role of NbOx in the OER mechanism, in which Fe serves as the active site and the Nb species can promote the conversion of *OH to *O intermediates to reduce the OER overpotential. [ABSTRACT FROM AUTHOR]

We report a FeW mixed composite for oxygen evolution reaction with a low overpotential and a long-term stability. A structural transformation of FeW oxide occurs during the OER process. Theoretical calculation indicates that FeOx is the OER-active site and the neighboring WOx improves the *OH to *O conversion on the Fe site. [ABSTRACT FROM AUTHOR]

Considering the radius similarity of Al3+ (0.50 Å) and Ga3+ (0.62 Å), Al−Co and Ga−Co layered double hydroxides (LDH) was prepared as precursor to improve the synergetic interaction of the transition metals. The Al−Co and Ga−Co spinel catalysts were obtained by the following calcination for the toluene oxidation. The Ga−Co (Ea=79.5 kJ mol−1) showed higher activity than the Al−Co (Ea=95.4 kJ mol−1), and it exhibited excellent stability and resistance to carbon deposition during a 50 h reaction period at 300 °C. Characterization results indicated that the improved activity of Ga−Co spinel could be attributed to the higher reducibility (H2‐TPR), more surface Co3+ and adsorbed oxygen in quantity (XPS) and adsorbed toluene (Toluene‐TPD) than Al−Co spinel. Compared with traditional Ga−Co binary catalyst, the spinel structure possessed more B‐sites cations outermost of the surface and surface oxygen vacancies for the toluene adsorption and ring‐open reaction. It′s all about how big you are: Considering the radius similarity of Al3+ (0.50 Å) and Ga3+ (0.62 Å), Al−Co and Ga−Co LDH were prepared as precursor to improve the synergetic interaction of the transition metals. The Al−Co and Ga−Co spinel were obtained by the following calcination for the toluene oxidation. Characterization results indicated that the improved activity of Ga−Co spinel could be attributed to the higher reducibility, more surface Co3+ and adsorbed oxygen in quantity and adsorbed toluene than Al−Co spinel." [ABSTRACT FROM AUTHOR]