The interplay between catalyst pore architecture and plasma discharge behavior is crucial for optimizing non-thermal plasma-catalytic processes. Porous carbon-supported molybdenum carbide catalysts (MCx, x = 10–1000, representing the nominal SiO2 template size) with tunable pore structures were synthesized by a hard-template method. Characterization confirmed molybdenum carbide formation within porous carbon frameworks with distinct pore dimensions. At a nominal power-supply input of 28 W, a gas hourly space velocity of 40000 h−1, and a CO2/H2 ratio of 1:3, MC1000 achieved 20.5
Efficient heat remove and uniform temperature distribution are critical for designing chemical reactors involving strongly exothermic gas-solid reactions, such as the various conversion of coal-based syngas to aromatics. Classical Fourier heat conduction theory implies that the effective heat transfer capability from spatial temperature gradients should be consistent with temporal temperature responses. However, whether this assumption remains in a gas-solid fluidized bed, as a typical heterogeneous multiphase system with complex dynamic structures remains unclear. In this study, the heat transfer behavior of fluidization was investigated spatially and temporally via steady-state temperature gradients and transient pulse method, respectively. Significant different equivalent heat transfer coefficients indicate an apparent spatiotemporal inconsistency in the effective heat transport of fluidization. Mechanistic analysis reveals that the spatial steady-state heat transfer process is mainly governed by the near-wall effective thermal-resistance region, whereas the temporal transient heat diffusion process is primarily affected by dynamic alternation between dilute and dense phases. Increasing the superficial gas velocity enhances both heat transfer processes, but the underlying enhancement mechanisms are fundamentally different. The former is mainly attributed to the weakening of the near-wall effective thermal-resistance region, while the latter is primarily caused by bubble-driven mixing enhancement. Further results demonstrate that modifying the heated-wall interfacial condition with thermally conductive grease markedly changes the spatial-domain heat-transfer response, highlighting the sensitivity of wall-dominated heat transfer to the near-wall interfacial state. These findings indicate that the effective heat transport capability in complex heterogeneous multiphase systems exhibits pronounced path dependence. This study provides a new theoretical basis for heat transfer pathways, thermal management optimization, and reactor design in strongly exothermic gas-solid reactors.
Epoxy resin (EP) has been widely utilized as a protective coating and structural composite; however, its high brittleness and low wear resistance limit its broader application. In this study, mesoporous silica nanotubes (MSNTs) were synthesized via a facile self-assembly route and incorporated into EP via solution mixing. The as-synthesized MSNTs exhibit a uniform tubular morphology and ordered mesoporous channels, disperse homogeneously within the EP matrix with strong interfacial adhesion, and effectively enhance the mechanical properties at low filler loading. By adding 1
The efficient upgrading of low-concentration H2S into valuable chemicals remains an unresolved economic challenge, as conventional catalytic processes have difficulty handling low-concentration H2S. Herein, we develop a new decoupled sulfidation-reduction catalytic cycle strategy that transforms low-concentration H2S in blast furnace gas into high-value carbonyl sulfide (COS). To implement this strategy, we designed a novel Fe-modified carbon nanofiber catalyst (Fe-CNF-15) for efficient H2S enrichment, followed by a reduction step utilizing the CO present in blast furnace gas to produce COS. Fe-CNF-15 delivers a sulfur capacity of 0.926 mmol·gcat−1 and achieves a high COS yield of up to 96.13
The co-combustion of sewage sludge (SS) with coal is a promising strategy for waste valorization; however, the impacts on gaseous pollutant emissions and heavy metal (HM) behavior remain inadequately characterized. This study investigates NO and SO2 release, the retention and extractability of six selected heavy metals (Mn, Zn, Cr, Ni, Cu, and Pb), and ash fusion characteristics during co-combustion. Co-firing with SS promoted early ignition and enhanced the coal combustion reactivity through the rapid release of volatiles, which facilitated fixed-carbon combustion; however, excessive SS blending reduced heat release owing to its low calorific value and high ash content. Concurrent in situ reductions of NO and SO2 were achieved. The enhanced combustion reactivity accelerated O2 consumption and promoted CO formation, creating a locally reducing atmosphere that contributed to the suppression of NO emissions. SO2 mitigation was associated with sulfur retention via the formation of stable sulfates by Ca-bearing minerals. Co-combustion enhanced the retention of Cr, Cu, Pb, and Zn in ash matrices while reducing their extractability, which is associated with HM-encapsulating silicate-, aluminosilicate-, and phosphate-rich phases. These refractory phases increased ash flow temperatures and inhibited liquid slag formation. Overall, SS/coal co-combustion reduces gaseous emissions and ash fusibility while stabilizing HMs in ashes.
