Sheng Su

Sodium suppresses NH ₃ and HCN release during the co-pyrolysis of coal and biomass by hindering the polycondensation of small aromatic rings and redistributing char nitrogen towards pyrrolic and quaternary forms.

Photothermal reforming of methanol offers a transformative approach for efficient on-site H2 production. However, its advancement is restricted by the structural and functional ambiguity of active sites, as well as the elusive nature of photothermal effects-mediated reaction mechanisms. Here, atomically defined CuZn bifunctional catalysts are engineered via hydroxide-targeted reduction strategy, which enables regulated active phase segregation of distinct metallic Cu−Cu and alloyed Cu−Zn coordination domains by fine tuning reactive metal-support interactions. Experimental and theoretical investigations reveal a definitive functional decoupling, where electron-rich Cu−Cu sites facilitate CH3OH dehydrogenation, and oxophilic Cu−Zn sites promote H2O dissociation. These specific coordination sites effectively activate the reactants through orbital hybridization and electron back donation. Crucially, isotope analysis combined with in situ spectroscopy reveals that beyond the prevalent formate pathway, photothermal synergistic effects unlock a parallel methyl formate-mediated pathway by promoting a Cannizzaro-type coupling of CH2O* intermediates, which was kinetically limited in pure thermocatalysis. Such a parallel dual-path mechanism contributes a high H2 production of 200.8 mmol g−1 h−1 over bifunctional CuZn catalysts at 200 °C with UV light irradiation, representing an advanced level for Cu-based catalysts under mild photothermal conditions. This study elucidates the atomic-level structure-activity relationship, and offers fundamental insights into harnessing photothermal synergistic effects.

To improve the flexibility and carbon reduction performance of coal-fired power plants, a solar-aided power generation (SAPG) system integrated with parabolic trough collectors and thermal energy storage (TES) was proposed and investigated using a combined Aspen Plus and System Advisor Model (SAM) framework. Two different integration schemes, namely SAPG-1 and SAPG-2, were evaluated under 100%, 75%, and 50% load conditions with a solar multiple of 2 and a TES duration of 6 h. The thermodynamic, economic, and environmental performances of the systems were comprehensively analyzed. The results show that TES significantly improves solar energy utilization, annual solar contribution, and system dispatchability. Compared with SAPG-2, SAPG-1 demonstrates superior thermodynamic and economic performance due to its lower boiler heat demand and more effective feedwater integration. At full load, the solar contribution of SAPG-1 with TES reaches 16.04%, while the annual solar energy production increases to 190.35 GWh with a capacity factor of 21.75%. In addition, TES integration effectively reduces the levelized cost of electricity and shortens the payback period under both CO₂ pricing and non-CO₂ pricing scenarios. The proposed SAPG framework demonstrates considerable potential for enhancing renewable energy utilization, operational flexibility, and economic feasibility in large-scale solar–coal hybrid power generation systems.

The global energy transition necessitates a higher share of renewable energy sources, requiring coal-fired power plants (CFPPs) to provide flexible operation to compensate for renewable volatility. Conventional CFPPs are constrained by fuel supply inertia, hindering their ability to meet dynamic grid demands. This paper proposes a novel solution by coupling a Small Pulverized Coal Silo (SPCS) system between the direct-firing pulverizing system and the boiler, breaking the fuel supply bottleneck to provide flexible and rapid fuel feeding. A high-fidelity dynamic simulation model was developed, comprising a 350 MW boiler integrated with the SPCS system. The boiler subsystem within this coupled model was rigorously validated against actual plant data. The results demonstrate that the SPCS system significantly enhances the boiler load change rate, with the average ramp rate increasing from 1.26 %Pe/min (without SPCS) to 3.23 %Pe/min (with SPCS) when supplying pulverized coal at 7 kg/s within 2 minutes during the 50%-75% load range of boiler. Moreover, under an identical SPCS coal feeding strategy, the enhancement in load change rate was more pronounced in the lower load range (50%-75%) compared to the higher load range (75%-100%). Furthermore, to ensure the energy-mass balance during the rapid fuel feeding process enabled by the SPCS, a regulation strategy based on synchronized feedwater compensation is proposed. The modulating effect of the feedwater-to-fuel compensation ratio (WFRSPCS) on the boiler's dynamic characteristics was investigated. An optimal ratio of WFRSPCS = 5 was identified, which successfully maintains the main steam temperature stability while simultaneously yielding an additional main steam flow increment of approximately 25.4 kg/s. Consequently, this strategy achieves a coordinated enhancement in both the load response speed and the thermal stability of the boiler unit.

The synthesis of carbon dots (CDs) from coal represents a promising strategy for advancing both the efficient, low-carbon utilization of coal resources and the cost-effective production of CDs. To enable the controlled, high-quality conversion of CDs from coal, a comprehensive understanding of the relationship between the coal chemical structure and the properties of CDs is crucial. This study prepared CDs from nine kinds of coal using a chemical oxidation method, and the correlations between properties of coal-based carbon dots and the original materials were revealed. The results show that the luminescence sites of coal-derived CDs are mostly distributed around 435 nm or 500 nm, where the former one relates to the confined sp² domains and the latter one is associated with the defect structure. Coal with a volatile content of about 20–30% in the nine samples was found to produce higher CD yields, with a maximum mass yield of 19.96%, accompanied by stronger fluorescence intensity. During chemical oxidation processes, the unsaturated double bonds (C=C, C=O) and aliphatic chains firstly break, and then aromatic clusters are formed by dehydrocyclization between carbon crystallites, followed by the introduction of a C–O group. The growth of the C–O group in the CDs contributes to a stronger fluorescence property. Furthermore, strong correlations were found between the carbon skeleton structure of raw coal and photoluminescence characteristics of corresponding CDs, as reflected by Raman parameters A_D1/A_G, I_D1/I_G, and FWHM_D. The findings offer significant insights into the precise modulation and control of coal-based carbon dot structures.