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Integrating a high proportion of intermittent renewable energy provides a solution for the higher peak-shaving capacity of coal-fired power plants. Oxy-fuel combustion is one of the most promising carbon reduction technologies for coal-fired power plants. This study has proposed a novel oxy-fuel power plant that is coupled with both liquid O2 storage and cold energy recovery systems in order to adapt to the peak-shaving requirements. The liquid O2 storage system uses cheap valley electricity to produce liquid O2 for a later use in the peak period to enhance the peak-shaving capacity. Meanwhile, the cold energy recovery system has been introduced to recover the physical latent energy during the phase change of liquid O2 to increase the power generation in the peak period. Technical economies of three power plants, i.e. a 330 MW (e) oxy-fuel power plant as reference (Case 1), the same power plant coupled with only liquid O2 storage system (Case 2), and the same power plant coupled with both liquid O2 storage and cold energy recovery systems (Case 3), have been analyzed and compared. Thermodynamic performance analysis indicates that the peaking capacity of Case 3 can reach the range of 106.03 to 294.22 MW (e), and the maximum peak-shaving coefficient can be as high as 2.77. Exergy analysis demonstrates that the gross exergy efficiency of Cases 2 and 3 reaches 32.18% and 33.57%, respectively, in the peak period, which are significantly higher than that of 26.70% in Case 1. Economic analysis shows that through selling the liquid O2 and liquid CO2, combined with carbon trading, the levelized cost of electricity (LCOE) of the three cases have been greatly reduced, with the lowest one of 30.90 USD/MWh shown in Case 3. For a comprehensive consideration, Case 3 can be considered a future reference of oxy-fuel power plant with the best thermodynamic and economic performance. [ABSTRACT FROM AUTHOR]

Chemical looping with O2 uncoupling aims at using an oxygen carrier (OC) with O2 uncoupling behaviour to promote fuel conversion. Natural ilmenite ores have been considered highly promising OCs for chemical looping technology; however, they do not possess any O2 uncoupling behaviour. Mn‐modified ilmenite ores as OCs are capable of O2 uncoupling, while most of them are synthesized via complicated procedures by using costly chemicals. In this study, a strategy of calcination treatment on ilmenite ores mixed with manganese ores has been established to introduce Mn into the ilmenite OCs, endowing them with O2 uncoupling behaviour in a simple and low‐cost manner. The O2 uncoupling behaviour from Mn‐modified ilmenite ores is mainly due to the newly formed (Fe1−xMnx)2O3/(Fe1−xMnx)3O4 crystal phases generated during the calcination treatment, which also alleviate the thermodynamic limit of the Mn2O3‐Mn3O4 redox pair. As a result, the Mn‐modified ilmenite ore OCs can release O2 at high temperatures when decreasing the oxygen partial pressure. But more importantly, the reduced OCs can be restored in the air isothermally. This established simple calcination treatment method can be used as a low‐cost strategy for producing ilmenite‐based OCs with O2 uncoupling behaviour. The O2 uncoupling behaviour is expected to be beneficial to chemical looping combustion of fuels, promote fuel conversion, minimize OC loading, and reduce energy consumption. [ABSTRACT FROM AUTHOR]

C 3 H 6 is a typical volatile organic compound (VOC) which is greatly harmful to the environment, however, it is difficult to achieve a complete C 3 H 6 removal at low temperature via the catalytic combustion treatment. In this study, high-performance catalysts of CuO CeO 2 composites were synthesized via a modified flame spray pyrolysis (FSP) method for the catalytic combustion of C 3 H 6. The CuO CeO 2 composites with different Cu molar ratios of 10, 25, 35, 50, and 75% were characterized by N 2 sorption-desorption analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM), H 2 temperature-programmed reduction (H 2 -TPR) and X-ray photoelectron spectroscopy (XPS). Results show that the composites preserve a nanometer-sized structure with stable micromorphology, which is hardly affected by the molar ratio of Cu. The FSP method is confirmed to be capable of producing solid solution oxides in the composites, which provide abundant reactive oxygen species and good reducibility. XPS, H 2 -TPR results indicate that Cu loading content has a significant impact on the catalytic properties of the prepared CuO CeO 2 catalysts by influencing the content of the solid solution. Compared with other methods, the optimized FSP method can significantly improve the loading of Cu without producing large crystalline CuO particles on the catalyst surface. C 3 H 6 conversion reached a 90% conversion at 380°C indicating an outstanding catalytic performance of the FSP-synthesized CuO CeO 2 catalysts with 35 mol% Cu loading. Moreover, the ignitability of C 3 H 6 is also affected by the catalyst's physicochemical properties, and different active species play the main role in different temperature intervals. [ABSTRACT FROM AUTHOR]

Pressurized oxy-fuel combustion of coal in fluidized bed (FB) holds the potential to realize low-cost CO 2 capture. However, the fundamental study in this manner is still rare due to the difficult access to the pressurized oxy-FB combustion tests. In this work, the experimental study of single char combustion was firstly conducted in a visualized pressurized FB combustor under various operating conditions. Then an experimentally verified particle-scale char combustion model was developed to reveal the dependence of char combustion on parameters. Results showed that the char conversion was accelerated with the increase of pressure, mainly due to the high oxygen diffusion and char gasification. The gasification played a non-negligible role in pressurized oxy-fuel combustion, especially under high oxygen concentration and bed temperature. Increasing oxygen concentration and bed temperature not only promotes the char oxidation rate and particle temperature, but also increases the gasification rate and the share of char conversion via gasification, resulting in shortening the burnout time of char. In addition, a higher fluidization number lowered both the burnout time and peak temperature of char particle, due to the simultaneous improvement of mass and heat transfer. The influences of char size and fluidization number on char gasification conversion ratio are very weak. In addition, the quantitative analysis of the influence of different operating parameters on the combustion process was obtained by model sensitivity analysis. [ABSTRACT FROM AUTHOR]

Abstract: Zeolites have many applications in the petrochemical and fine chemical industry and their functionalization does expand the spectrum of potentials. However, the integration of functional nanocrystals into zeolite frameworks with controlled size, dispersion, and crystallization behavior still remains a significant challenge. Here, a new synthesis of magnetic functioned ZSM‐5 zeolite catalysts via a CoFe2O4 nanocrystal mediated crystallization strategy is reported. It is found that high crystallinity of CoFe2O4 nanocrystals results in a well‐dispersed encapsulation of them into a single‐crystal of ZSM‐5 due to non‐further‐grown nanocrystals during the fast ZSM‐5 growth. On the contrary, low crystallinity of CoFe2O4 nanocrystals leads to the polycrystalline zeolite growth due to the secondary growth of nanocrystals accompanied by the zeolite crystallization and large lattice mismatch between them. The successful encapsulation of small CoFe2O4 nanocrystals (≈4 nm) into single crystals lies on the preattachment of them into solid silica gel. During the growth of ZSM‐5 crystals, no secondary growth of nanocrystals happens and its motion is restricted. The encapsulation of magnetic CoFe2O4 nanocrystals not only endows magnetic function into zeolites for the first time, but also does not impact catalytic performance of ZSM‐5 in acetalization of cyclohexanone with methanol, which is highly promising in catalytic industries. [ABSTRACT FROM AUTHOR]