Articles in press have been peer-reviewed and accepted, which are not yet assigned to volumes /issues, but are citable by Digital Object Identifier (DOI).
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doi: 10.1016/S1872-5813(23)60402-5
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doi: 10.1016/S1872-5813(23)60405-0
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doi: 10.1016/S1872-5813(23)60403-7
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doi: 10.1016/S1872-5813(23)60390-1
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doi: 10.1016/S1872-5813(23)60387-1
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doi: 10.1016/S1872-5813(23)60400-1
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doi: 10.19906/j.cnki.JFCT.2023079
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doi: 10.19906/j.cnki.JFCT.2023087
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doi: 10.19906/j.cnki.JFCT.2023084
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doi: 10.19906/j.cnki.JFCT.2023083
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doi: 10.19906/j.cnki.JFCT.2023085
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doi: 10.19906/j.cnki.JFCT.2023088
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doi: 10.19906/j.cnki.JFCT.2024001
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doi: 10.1016/S1872-5813(24)60432-9
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doi: 10.19906/j.cnki.JFCT.2024002
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doi: 10.1016/S1872-5813(23)60412-8
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The research progress of formation and control on the N-containing compound of biomass pyrolysis gas
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doi: 10.19906/j.cnki.JFCT.2023090
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doi: 10.19906/j.cnki.JFCT.2023077
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doi: 10.19906/j.cnki.JFCT.2023080
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doi: 10.1016/S1872-5813(23)60393-7
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doi: 10.19906/j.cnki.JFCT.2023061
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doi: 10.1016/S1872-5813(23)60397-4
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doi: 10.1016/S1872-5813(23)60404-9
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doi: 10.1016/S1872-5813(23)60401-3
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doi: 10.1016/S1872-5813(23)60410-4
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doi: 10.1016/S1872-5813(23)60409-8
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doi: 10.19906/j.cnki.JFCT.2023089
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doi: 10.1016/S1872-5813(23)60408-6
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doi: 10.1016/S1872-5813(23)60407-4
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doi: 10.1016/S1872-5813(23)60406-2
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Hydrothermal Flowthrough Pretreatment of Biomass and Pyrolysis Characteristics of Its Residual Solid
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doi: 10.19906/j.cnki.JFCT.2023082
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doi: 10.1016/S1872-5813(23)60398-6
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doi: 10.1016/S1872-5813(23)60394-9
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doi: 10.1016/S1872-5813(23)60396-2
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doi: 10.19906/j.cnki.JFCT.2023075
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doi: 10.1016/S1872-5813(23)60399-8
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doi: 10.19906/j.cnki.JFCT.2023081
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doi: 10.19906/j.cnki.JFCT.2023076
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doi: 10.19906/j.cnki.JFCT.2023078
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2024, 52(3): 293-304.
doi: 10.1016/S1872-5813(23)60391-3
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A series of Cu-Mn-Zn/ZrO2 catalysts with different Zn contents were prepared by sol-gel method and characterized by XRD, BET, TPR, N2O-adsorption, XPS, TPD and in-situ DRIFTS. It was found that by increasing a certain amount of Zn, the catalytic activity for CO2 hydrogenation increased. Among all samples, Cu3MnZn0.5Zr0.5 (CMZZ-0.5) possessed the best CO2 conversion (6.5%) and methanol selectivity (73.7%) at 250 °C and 5 MPa. Characterization results showed that Zn entered the Cu1.5Mn1.5O4 spinel structure, forming ZnOx and thus more surface OH groups. This increased the content of Cu0 and Cuα+, which improved the activation of H2 and CO2. The pathway of CO2 to methanol was also clarified through in-situ DRIFTS.
A series of Cu-Mn-Zn/ZrO2 catalysts with different Zn contents were prepared by sol-gel method and characterized by XRD, BET, TPR, N2O-adsorption, XPS, TPD and in-situ DRIFTS. It was found that by increasing a certain amount of Zn, the catalytic activity for CO2 hydrogenation increased. Among all samples, Cu3MnZn0.5Zr0.5 (CMZZ-0.5) possessed the best CO2 conversion (6.5%) and methanol selectivity (73.7%) at 250 °C and 5 MPa. Characterization results showed that Zn entered the Cu1.5Mn1.5O4 spinel structure, forming ZnOx and thus more surface OH groups. This increased the content of Cu0 and Cuα+, which improved the activation of H2 and CO2. The pathway of CO2 to methanol was also clarified through in-situ DRIFTS.
2024, 52(3): 305-312.
doi: 10.19906/j.cnki.JFCT.2023060
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The massive emission of the greenhouse gas CO2 has caused problems such as global warming and ecological damage. How to effectively utilize CO2 as a resource and create economic benefits has attracted much attention in recent years. In this paper, a series of La-doped ZnO catalysts were designed and synthesized targeting the synthesis of ethylene carbonate (EC) from CO2 and ethylene glycol (EG), which could modulate the Lewis acid-base sites on the ZnO surface, and the catalyst activity was investigated under additive-free conditions. La-ZnO-1%-550℃ had the best catalytic activity with 0.54% conversion of EG, 7.326 mmol/(h∙g) and 99% space-time yield and selectivity of EC at 130 ℃, 4 MPa CO2, and 1 h with good stability. Combined with the analysis of the crystal structure, morphology and surface acid-base of the catalysts, the results showed that La was uniformly distributed in the ZnO hollow nanosheets, and the surface of the La-doped ZnO calcined at 550 ℃ had the most Lewis acid-base sites, and the catalytic activity of the catalysts increased with the increase of moderate to strong Lewis acid-base sites.
The massive emission of the greenhouse gas CO2 has caused problems such as global warming and ecological damage. How to effectively utilize CO2 as a resource and create economic benefits has attracted much attention in recent years. In this paper, a series of La-doped ZnO catalysts were designed and synthesized targeting the synthesis of ethylene carbonate (EC) from CO2 and ethylene glycol (EG), which could modulate the Lewis acid-base sites on the ZnO surface, and the catalyst activity was investigated under additive-free conditions. La-ZnO-1%-550℃ had the best catalytic activity with 0.54% conversion of EG, 7.326 mmol/(h∙g) and 99% space-time yield and selectivity of EC at 130 ℃, 4 MPa CO2, and 1 h with good stability. Combined with the analysis of the crystal structure, morphology and surface acid-base of the catalysts, the results showed that La was uniformly distributed in the ZnO hollow nanosheets, and the surface of the La-doped ZnO calcined at 550 ℃ had the most Lewis acid-base sites, and the catalytic activity of the catalysts increased with the increase of moderate to strong Lewis acid-base sites.
2024, 52(3): 313-322.
doi: 10.19906/j.cnki.JFCT.2023058
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Methane dry reforming reaction is a promising route for the valorization of both CO2 and CH4. However, the catalysts usually suffered from the coking deactivation and the sintering of active phase under the harsh reaction conditions. In this paper, the Mg-Al spinel support with different Mg content prepared by the solvent evaporation-induced self-assembly method was investigated. With this support, Ni/MgAl2O4 was used as the catalyst for methane dry reforming to syngas. XRD, BET and TEM results showed that the addition of appropriate amount of magnesium (10%−15%) was beneficial to the formation of highly stable ordered mesoporous magnesia spinel support with large specific surface area, which can confine the Ni particles in the pore structure and thus enhance the nickel dispersion and improve the resistance of coke formation under high temperature. H2-TPR and XPS analysis indicated the addition of 10%−15% magnesium can promote the interaction between Ni and MgAl2O4, inhibiting the agglomeration of Ni and the coke formation with the active surface-adsorbed oxygen species. Detailed activity tests showed that Ni/MgAl2O4 catalysts with 10%−15% magnesium content has high CH4 and CO2 conversion. During the long-term test for 180 h, the Ni/15-MAO catalyst exihibited the CH4 and CO2 conversions of 92.6% and 92.5%, respectively. The coke deposition percentage was only 0.89% and the grain size of Ni was maintained after reaction.
Methane dry reforming reaction is a promising route for the valorization of both CO2 and CH4. However, the catalysts usually suffered from the coking deactivation and the sintering of active phase under the harsh reaction conditions. In this paper, the Mg-Al spinel support with different Mg content prepared by the solvent evaporation-induced self-assembly method was investigated. With this support, Ni/MgAl2O4 was used as the catalyst for methane dry reforming to syngas. XRD, BET and TEM results showed that the addition of appropriate amount of magnesium (10%−15%) was beneficial to the formation of highly stable ordered mesoporous magnesia spinel support with large specific surface area, which can confine the Ni particles in the pore structure and thus enhance the nickel dispersion and improve the resistance of coke formation under high temperature. H2-TPR and XPS analysis indicated the addition of 10%−15% magnesium can promote the interaction between Ni and MgAl2O4, inhibiting the agglomeration of Ni and the coke formation with the active surface-adsorbed oxygen species. Detailed activity tests showed that Ni/MgAl2O4 catalysts with 10%−15% magnesium content has high CH4 and CO2 conversion. During the long-term test for 180 h, the Ni/15-MAO catalyst exihibited the CH4 and CO2 conversions of 92.6% and 92.5%, respectively. The coke deposition percentage was only 0.89% and the grain size of Ni was maintained after reaction.
2024, 52(3): 323-334.
doi: 10.1016/S1872-5813(23)60395-0
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The reaction mechanism of methanol/dimethyl ether (DME) carbonylation catalyzed by isomorphously substituted B-, Al-, and Ga-MOR zeolites (B/Al/Ga-MOR) was comparatively investigated by the density functional theory (DFT) calculations. The commonalities and differences between methanol and dimethyl ether as the reactant as well as among various MOR zeolites in the catalytic reaction pathways were disclosed, where one Si atom was substituted by B, Al or Ga at the 8-ring side pockets T3 sites or the 12-ring channels T4 sites of MOR. The results indicate that the insertion of CO into methoxy group to form acetyl groups follows the SN2 mechanism and is the rate-determining step in the carbonylation reactions. Under 473 K, either methanol or dimethyl ether is used as feedstock, the formed acetyl group prefers to interact with CH3O in methanol to form methyl acetate. The T3 sites show better carbonylation selectivity, whereas T4 sites display better trimethoxonium ions selectivity which favors the generation of aromatics and leads to the catalyst deactivation. Comparing with Al-MOR, the introduction of Ga and B at the T3 sites increases the free energy barriers of carbonylation, whereas the introduction of Ga and B in particular at the T4 sites can substantially increase the energy barriers of generating trimethyloxonium ions, which can effectively suppress the side reaction and improve the catalyst stability. This work contributes to the understanding of the catalytic roles of various acidic sites in different channels of the MOR zeolites and provides certain theoretical support for tailoring and designing efficient MOR zeolite catalysts for methanol/dimethyl ether carbonylation.
The reaction mechanism of methanol/dimethyl ether (DME) carbonylation catalyzed by isomorphously substituted B-, Al-, and Ga-MOR zeolites (B/Al/Ga-MOR) was comparatively investigated by the density functional theory (DFT) calculations. The commonalities and differences between methanol and dimethyl ether as the reactant as well as among various MOR zeolites in the catalytic reaction pathways were disclosed, where one Si atom was substituted by B, Al or Ga at the 8-ring side pockets T3 sites or the 12-ring channels T4 sites of MOR. The results indicate that the insertion of CO into methoxy group to form acetyl groups follows the SN2 mechanism and is the rate-determining step in the carbonylation reactions. Under 473 K, either methanol or dimethyl ether is used as feedstock, the formed acetyl group prefers to interact with CH3O in methanol to form methyl acetate. The T3 sites show better carbonylation selectivity, whereas T4 sites display better trimethoxonium ions selectivity which favors the generation of aromatics and leads to the catalyst deactivation. Comparing with Al-MOR, the introduction of Ga and B at the T3 sites increases the free energy barriers of carbonylation, whereas the introduction of Ga and B in particular at the T4 sites can substantially increase the energy barriers of generating trimethyloxonium ions, which can effectively suppress the side reaction and improve the catalyst stability. This work contributes to the understanding of the catalytic roles of various acidic sites in different channels of the MOR zeolites and provides certain theoretical support for tailoring and designing efficient MOR zeolite catalysts for methanol/dimethyl ether carbonylation.
2024, 52(3): 335-342.
doi: 10.19906/j.cnki.JFCT.2023086
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Dimethyl carbonate (DMC) is an important and environmentally friendly chemical intermediate to meet the growing demand for a clean and sustainable energy supply. Among several routes for DMC synthesis, the oxidative carbonylation of methanol has attracted much attention with the advantages of a high utilization rate of carbon source, moderate operating conditions and environmental benefits. More importantly, the oxidative carbonylation of methanol is an important development route of modern coal chemical industry in China, and the key lies in the design of highly efficient catalysts. Copper-based catalysts have been used extensively in this reaction. Problems, such as reactor corrosion and catalyst deactivation, occur with chlorine-containing catalysts. The development of chlorine-free catalysts is the focus of current research. Recently, Cu-based catalysts supported on carbon materials have been used extensively in DMC synthesis because of its high activity, high selectivity and facile preparation process. However, the carbon-supported Cu catalysts suffer from the leaching and aggregation of Cu nanoparticles (NPs) in the harsh reaction conditions of high temperature, high pressure as well as severe stirring, leading to the deactivation. It has become a key scienctific problem that needs to be addressed urgently. In our previous studies, several strategies have been attempted to solve the deactivation problem caused by these reasons. For instance, encapsulating Cu NPs with hollow porous carbon spheres or mesoporous carbon materials. Besides, the introduction of N species in the carbon framework or sulfonic acid groups and oxygen-containing groups on the surface of carbon materials leads to an anchoring effect on Cu NPs. Great progress has been made via these methods, yet still unsatisfactory. Supported metal clusters have adjacent metal sites, countable numbers of atoms in each clusters, and limited size range (normally smaller than 2 nm). Benefiting from these distinct geometric and electronic structures, supported metal clusters can trigger synergistic effects among every metal atom, and thus exhibiting enhanced catalytic activity and selectivity in catalysis. Besides, the strong metal-support interaction on supported metal clusters improve the stability of metal clusters, enhancing the catalytic stability. To prevent the aggregation of metal clusters, the metal loading of supported metal clusters catalysts are generally kept at a low level (≤1%). However, catalysts with insufficient numbers of active sites always lead to compromised mass-activity, which greatly restrict them from industrial applications. Hence, the synthesis of supported metal clusters with high metal loading and high stability is a great challenge. In this study, the Cu clusters catalysts with high Cu loading were synthesized via liquid phase reconstruction method under the condition of water and CO. The optimal 15Cu/NCNS-12-CO exhibited superb activity with STYDMC of 3520 mg/(g·h) and stability with the loss rate of 28% after 10 cycles. A series of characterization showed that the strongly reducing CO not only resulted in the partial reconstruction of copper nanoparticles (from ~9.7 nm to ~1.34 nm), but also effectively maintained the existence of Cu0 species, improving the catalytic activity and stability. Further investigation showed that the reconstruction of Cu nanoparticles was dependent on the interaction of atmosphere-metal-support, and was reversible under the oxidation and reducing atmosphere.
Dimethyl carbonate (DMC) is an important and environmentally friendly chemical intermediate to meet the growing demand for a clean and sustainable energy supply. Among several routes for DMC synthesis, the oxidative carbonylation of methanol has attracted much attention with the advantages of a high utilization rate of carbon source, moderate operating conditions and environmental benefits. More importantly, the oxidative carbonylation of methanol is an important development route of modern coal chemical industry in China, and the key lies in the design of highly efficient catalysts. Copper-based catalysts have been used extensively in this reaction. Problems, such as reactor corrosion and catalyst deactivation, occur with chlorine-containing catalysts. The development of chlorine-free catalysts is the focus of current research. Recently, Cu-based catalysts supported on carbon materials have been used extensively in DMC synthesis because of its high activity, high selectivity and facile preparation process. However, the carbon-supported Cu catalysts suffer from the leaching and aggregation of Cu nanoparticles (NPs) in the harsh reaction conditions of high temperature, high pressure as well as severe stirring, leading to the deactivation. It has become a key scienctific problem that needs to be addressed urgently. In our previous studies, several strategies have been attempted to solve the deactivation problem caused by these reasons. For instance, encapsulating Cu NPs with hollow porous carbon spheres or mesoporous carbon materials. Besides, the introduction of N species in the carbon framework or sulfonic acid groups and oxygen-containing groups on the surface of carbon materials leads to an anchoring effect on Cu NPs. Great progress has been made via these methods, yet still unsatisfactory. Supported metal clusters have adjacent metal sites, countable numbers of atoms in each clusters, and limited size range (normally smaller than 2 nm). Benefiting from these distinct geometric and electronic structures, supported metal clusters can trigger synergistic effects among every metal atom, and thus exhibiting enhanced catalytic activity and selectivity in catalysis. Besides, the strong metal-support interaction on supported metal clusters improve the stability of metal clusters, enhancing the catalytic stability. To prevent the aggregation of metal clusters, the metal loading of supported metal clusters catalysts are generally kept at a low level (≤1%). However, catalysts with insufficient numbers of active sites always lead to compromised mass-activity, which greatly restrict them from industrial applications. Hence, the synthesis of supported metal clusters with high metal loading and high stability is a great challenge. In this study, the Cu clusters catalysts with high Cu loading were synthesized via liquid phase reconstruction method under the condition of water and CO. The optimal 15Cu/NCNS-12-CO exhibited superb activity with STYDMC of 3520 mg/(g·h) and stability with the loss rate of 28% after 10 cycles. A series of characterization showed that the strongly reducing CO not only resulted in the partial reconstruction of copper nanoparticles (from ~9.7 nm to ~1.34 nm), but also effectively maintained the existence of Cu0 species, improving the catalytic activity and stability. Further investigation showed that the reconstruction of Cu nanoparticles was dependent on the interaction of atmosphere-metal-support, and was reversible under the oxidation and reducing atmosphere.
2024, 52(3): 343-352.
doi: 10.19906/j.cnki.JFCT.2023071
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Hydrodeoxygenation of lignin bio-oil to prepare liquid fuels is a very promising route. In this paper, a series of catalysts (Ru/CeO2, Ru/Nb2O5, Ru/ZrO2, Ru/Al2O3 and Ru/CeOx) supported on metal oxides were prepared by incipient wetness impregnation method, which were used to study the upgrading and hydrogenation of lignin-derived phenolic compounds phenol to cyclohexanol. By means of X-ray crystal diffraction (XRD), scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS), the structure and physical and chemical characteristics of the prepared catalyst were characterized. It was found that the oxygen vacancies contained in Ru/CeOx could adsorb the raw materials with oxygen groups well, which was beneficial to the efficient hydrogenation of phenol. At the same time, XPS showed that the effective active centers in Ru/CeOx, RuO2 and Ru0, were active sites for catalytic hydrogenation. Therefore, the combined action of oxygen vacancies and metal active sites made the catalyst have good hydrogenation activity. The effects of reaction temperature, pressure and time on hydrogenation were also investigated. It was found that the catalyst could completely convert phenol at a mild temperature (140 ℃) and the yield of cyclohexanol was 90.2%. The cycle characteristics of the catalyst were investigated, and it was found that the catalyst still showed excellent hydrogenation activity after being recycled for 4 times. At the same time, the intermediate products in the hydrogenation process were detected by GC-MS, and then the reaction path of phenol hydrogenation process was deduced.
Hydrodeoxygenation of lignin bio-oil to prepare liquid fuels is a very promising route. In this paper, a series of catalysts (Ru/CeO2, Ru/Nb2O5, Ru/ZrO2, Ru/Al2O3 and Ru/CeOx) supported on metal oxides were prepared by incipient wetness impregnation method, which were used to study the upgrading and hydrogenation of lignin-derived phenolic compounds phenol to cyclohexanol. By means of X-ray crystal diffraction (XRD), scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS), the structure and physical and chemical characteristics of the prepared catalyst were characterized. It was found that the oxygen vacancies contained in Ru/CeOx could adsorb the raw materials with oxygen groups well, which was beneficial to the efficient hydrogenation of phenol. At the same time, XPS showed that the effective active centers in Ru/CeOx, RuO2 and Ru0, were active sites for catalytic hydrogenation. Therefore, the combined action of oxygen vacancies and metal active sites made the catalyst have good hydrogenation activity. The effects of reaction temperature, pressure and time on hydrogenation were also investigated. It was found that the catalyst could completely convert phenol at a mild temperature (140 ℃) and the yield of cyclohexanol was 90.2%. The cycle characteristics of the catalyst were investigated, and it was found that the catalyst still showed excellent hydrogenation activity after being recycled for 4 times. At the same time, the intermediate products in the hydrogenation process were detected by GC-MS, and then the reaction path of phenol hydrogenation process was deduced.
2024, 52(3): 353-361.
doi: 10.19906/j.cnki.JFCT.2023072
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Fe-Al-Ti oxygen carriers have good cycling stability and good properties of anti-carbon deposition in the chemical looping hydrogen generation (CLHG) process. However, the formation of FeAl2O4 reduces hydrogen yield and increases sintering. To weaken the formation of FeAl2O4 and to promote properties, the core-shell oxygen carriers of Fe@Al-Ti were prepared by self-assembly template combustion method, which took TiO2 as the inter-layer to separate Fe2O3 and Al2O3. The effect of multi-layer core-shell structure on reaction performance was evaluated on a fixed bed. The results indicated that the inter-layer of Fe@Al-Ti oxygen carriers effectively weakened the contact between Fe2O3 and Al2O3, thus reducing the formation of FeAl2O4 and improving properties of anti-sintering. The Fe@Al-Ti oxygen carriers significantly prevented carbon deposition and surface agglomeration, and had great cycling stability during the CLHG cycles. The core-shell oxygen carrier with a molar ratio of Al∶Ti=3.5∶1 got the highest carbon conversion rate and H2 yield, and oxygen storage capacity in a single cycle, with 57.4%, 75.0%, and 6.01 mmol/g, respectively, which were 28.4%, 30.0%, and 26.9% higher than those of non core-shell Fe-Al-Ti oxygen carriers.
Fe-Al-Ti oxygen carriers have good cycling stability and good properties of anti-carbon deposition in the chemical looping hydrogen generation (CLHG) process. However, the formation of FeAl2O4 reduces hydrogen yield and increases sintering. To weaken the formation of FeAl2O4 and to promote properties, the core-shell oxygen carriers of Fe@Al-Ti were prepared by self-assembly template combustion method, which took TiO2 as the inter-layer to separate Fe2O3 and Al2O3. The effect of multi-layer core-shell structure on reaction performance was evaluated on a fixed bed. The results indicated that the inter-layer of Fe@Al-Ti oxygen carriers effectively weakened the contact between Fe2O3 and Al2O3, thus reducing the formation of FeAl2O4 and improving properties of anti-sintering. The Fe@Al-Ti oxygen carriers significantly prevented carbon deposition and surface agglomeration, and had great cycling stability during the CLHG cycles. The core-shell oxygen carrier with a molar ratio of Al∶Ti=3.5∶1 got the highest carbon conversion rate and H2 yield, and oxygen storage capacity in a single cycle, with 57.4%, 75.0%, and 6.01 mmol/g, respectively, which were 28.4%, 30.0%, and 26.9% higher than those of non core-shell Fe-Al-Ti oxygen carriers.
2024, 52(3): 362-372.
doi: 10.1016/S1872-5813(23)60388-3
Abstract:
Red mud is a solid waste in aluminum industry and has been proven to be an efficient alternative to NOx selective catalytic reduction (SCR) catalysts. Acid washing treatment to red mud can improve its alkalinity and surface properties, and increase the conversion rate of NOx. In this paper, Cu, Ce, and Cu/Ce was supported on acid washed red mud and NOx catalytic conversion performance on metal modified red mud catalysts was studied. The research results indicate that Cu+ and Cu2+ in the Cu supported catalyst effectively promote NO conversion rate of red mud in low-temperature (200−300 ℃) flue gas, reaching a maximum of 90.7%; Ce3+ and Ce4+ in Ce supported catalysts effectively promote the NO conversion rate of red mud in flue gas at 200–400 ℃, reaching a maximum of 94.0%; Cu/Ce supporting exhibits better NO conversion rate than single metal supported catalysts at low-temperatures, the optimal Cu∶Ce ratio for supporting is 1∶1; and also exhibits better NO conversion rate than Cu supported catalysts at high-temperature (300−400 ℃), reaching a maximum of 95.5%. The reason may be that under the synergistic effect of Cu/Ce, ACRM-Cu1Ce1 has stronger low-temperature redox ability, higher weak acidic peaks, higher average oxidation state of Fe ions, and higher Cu+ content.
Red mud is a solid waste in aluminum industry and has been proven to be an efficient alternative to NOx selective catalytic reduction (SCR) catalysts. Acid washing treatment to red mud can improve its alkalinity and surface properties, and increase the conversion rate of NOx. In this paper, Cu, Ce, and Cu/Ce was supported on acid washed red mud and NOx catalytic conversion performance on metal modified red mud catalysts was studied. The research results indicate that Cu+ and Cu2+ in the Cu supported catalyst effectively promote NO conversion rate of red mud in low-temperature (200−300 ℃) flue gas, reaching a maximum of 90.7%; Ce3+ and Ce4+ in Ce supported catalysts effectively promote the NO conversion rate of red mud in flue gas at 200–400 ℃, reaching a maximum of 94.0%; Cu/Ce supporting exhibits better NO conversion rate than single metal supported catalysts at low-temperatures, the optimal Cu∶Ce ratio for supporting is 1∶1; and also exhibits better NO conversion rate than Cu supported catalysts at high-temperature (300−400 ℃), reaching a maximum of 95.5%. The reason may be that under the synergistic effect of Cu/Ce, ACRM-Cu1Ce1 has stronger low-temperature redox ability, higher weak acidic peaks, higher average oxidation state of Fe ions, and higher Cu+ content.
2024, 52(3): 373-383.
doi: 10.19906/j.cnki.JFCT.2023073
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A series of Cu(x)Co(y)Ce(z)-LDH precursors were synthesized by one-step hydrothermal method, and Cu(x)Co(y)Ce(z)O mixed metal oxide catalysts were prepared after calcination and used to study the selective catalytic reduction of NO by C3H6 (C3H6-SCR) with a fixed bed micro-reactor. Due to the strong synergy between Cu, Co and Ce, Cu(0.21)Co(0.48)Ce(0.31)O achieves 95% NO conversion and 90% N2 selectivity at 225 ℃. In addition, ICP, XRD, TEM, XPS, H2-TPR were used to characterize the basic physical-chemical properties of the catalysts to investigate the relationship between physicochemical properties and catalytic reduction abilities. XRD results show that solid solutions are formed between Cu, Co and Ce, which promotes the dispersion of active metals. XPS and H2-TPR further demonstrate that redox reactions occur between Cu and Co, promoting the formation of oxygen vacancies, thereby improving their catalytic reduction capacity.
A series of Cu(x)Co(y)Ce(z)-LDH precursors were synthesized by one-step hydrothermal method, and Cu(x)Co(y)Ce(z)O mixed metal oxide catalysts were prepared after calcination and used to study the selective catalytic reduction of NO by C3H6 (C3H6-SCR) with a fixed bed micro-reactor. Due to the strong synergy between Cu, Co and Ce, Cu(0.21)Co(0.48)Ce(0.31)O achieves 95% NO conversion and 90% N2 selectivity at 225 ℃. In addition, ICP, XRD, TEM, XPS, H2-TPR were used to characterize the basic physical-chemical properties of the catalysts to investigate the relationship between physicochemical properties and catalytic reduction abilities. XRD results show that solid solutions are formed between Cu, Co and Ce, which promotes the dispersion of active metals. XPS and H2-TPR further demonstrate that redox reactions occur between Cu and Co, promoting the formation of oxygen vacancies, thereby improving their catalytic reduction capacity.
2016, 44(7): 777-783.
摘要:
通过对28个最大镜质组反射率0.30%-2.05%镜煤样品的X射线衍射(XRD) 分析, 获得XRD结构参数, 得到这些参数随反射率增大呈现的阶段性规律。在镜质组反射率小于1.0%阶段, La和Lc急剧增加, d002迅速减小, 含氧官能团的脱落和脂肪长度支链化程度减小占主导; 在1.0%-1.6%阶段, La持续增加, d002先增加后减小, Lc先减小然后趋于平稳, 芳香体系脱氢和调整空间位阻同时进行; 在1.6%-2.0%阶段, d002持续减小, Lc和La的增大, 煤结构演化以芳构化为主。XRD结构参数演化与第一、二次煤化作用跃变关系密切。
通过对28个最大镜质组反射率0.30%-2.05%镜煤样品的X射线衍射(XRD) 分析, 获得XRD结构参数, 得到这些参数随反射率增大呈现的阶段性规律。在镜质组反射率小于1.0%阶段, La和Lc急剧增加, d002迅速减小, 含氧官能团的脱落和脂肪长度支链化程度减小占主导; 在1.0%-1.6%阶段, La持续增加, d002先增加后减小, Lc先减小然后趋于平稳, 芳香体系脱氢和调整空间位阻同时进行; 在1.6%-2.0%阶段, d002持续减小, Lc和La的增大, 煤结构演化以芳构化为主。XRD结构参数演化与第一、二次煤化作用跃变关系密切。
2016, 44(4): 385-393.
摘要:
以11种炼焦煤为研究对象,分别进行FT-IR和黏结指数G测试。采用PeakFit软件对FT-IR谱峰进行分峰拟合和定量计算,研究炼焦煤特征官能团含量与其黏结性间的关系。结果表明,煤黏结性大小与其FT-IR吸收峰密切相关,特别是3 000-2 800和3 700-3 000 cm-1两个吸收带;脂肪族结构是煤黏结性形成的主要决定因素,通常脂肪链越短或支链化程度越高,越有利于煤的黏结性形成;含-OH(或-NH)的氢键缔合结构可以与脂肪链协同作用,共同决定煤的黏结性能。不论煤分子有多大,只要是结构单元缩合度较小而作为桥键的脂肪链较多的结构形式,在热解过程中就会生成大量适度分子量、以结构单元为基元的液相物质。氢键是煤中主要的分子间作用形式,当若干形成氢键的官能团聚集缔合时,其相互作用会更强,甚至会形成类似超分子的结构;在形成胶质体阶段,这类氢键缔合的结构也会被打破,并形成以胶质体液相为主的物质。这些液相物质的存在,有利于胶质体的流动、黏连和固化成为半焦,从而最终获得优越的黏结性。
以11种炼焦煤为研究对象,分别进行FT-IR和黏结指数G测试。采用PeakFit软件对FT-IR谱峰进行分峰拟合和定量计算,研究炼焦煤特征官能团含量与其黏结性间的关系。结果表明,煤黏结性大小与其FT-IR吸收峰密切相关,特别是3 000-2 800和3 700-3 000 cm-1两个吸收带;脂肪族结构是煤黏结性形成的主要决定因素,通常脂肪链越短或支链化程度越高,越有利于煤的黏结性形成;含-OH(或-NH)的氢键缔合结构可以与脂肪链协同作用,共同决定煤的黏结性能。不论煤分子有多大,只要是结构单元缩合度较小而作为桥键的脂肪链较多的结构形式,在热解过程中就会生成大量适度分子量、以结构单元为基元的液相物质。氢键是煤中主要的分子间作用形式,当若干形成氢键的官能团聚集缔合时,其相互作用会更强,甚至会形成类似超分子的结构;在形成胶质体阶段,这类氢键缔合的结构也会被打破,并形成以胶质体液相为主的物质。这些液相物质的存在,有利于胶质体的流动、黏连和固化成为半焦,从而最终获得优越的黏结性。
2016, 44(3): 279-286.
摘要:
利用高分辨率透射电子显微镜(HRTEM) 分析了三种不同变质程度煤样的结构特征.基于傅里叶-反傅里叶变换方法, 并结合Matlab、Arcgis和AutoCAD软件, 通过图像分析技术, 获得了HRTEM照片的晶格条纹参数.结果表明, 三种煤样的晶格条纹呈现不同特征, 按条纹长度分别归属于1×1-8×8共计八个类型.以3×3为临界点, 在1×1和2×2中, ML-8中芳香层片的比例高于DP-4和XM-3;在3×3-8×8中, ML-8中芳香层片的比例低于DP-4和XM-3.对比HRTEM和XRD参数d002发现, 随着镜质组反射率的增加d002都呈现递减趋势.
利用高分辨率透射电子显微镜(HRTEM) 分析了三种不同变质程度煤样的结构特征.基于傅里叶-反傅里叶变换方法, 并结合Matlab、Arcgis和AutoCAD软件, 通过图像分析技术, 获得了HRTEM照片的晶格条纹参数.结果表明, 三种煤样的晶格条纹呈现不同特征, 按条纹长度分别归属于1×1-8×8共计八个类型.以3×3为临界点, 在1×1和2×2中, ML-8中芳香层片的比例高于DP-4和XM-3;在3×3-8×8中, ML-8中芳香层片的比例低于DP-4和XM-3.对比HRTEM和XRD参数d002发现, 随着镜质组反射率的增加d002都呈现递减趋势.
2016, 44(3): 263-272.
摘要:
利用XRD和FT-IR考察了高温弱还原气氛下Na2O对两种硅铝含量不同的煤灰中矿物质组成的影响, 揭示了Na2O影响煤灰熔融特性的本质.通过FactSage计算了高温下矿物质反应的ΔG, 探讨了Na2O影响煤灰中矿物质组成的机理.结果表明, Na2O对煤灰矿物质组成的影响与原煤灰的硅铝含量密切相关.硅铝总含量82.89%的煤灰, Na2O含量为5%-20%时, 钠长石和霞石的生成是煤灰熔融温度降低的主要原因; 当Na2O含量大于20%时, 导致煤灰熔融温度降低的原因是霞石的生成.硅铝总含量47.85%的煤灰, Na2O含量小于10%时, 没有含钠矿物质生成; 当Na2O含量大于10%时, 主要生成菱硅钙钠石、青金石和含钠的硅铝酸盐矿物, 导致煤灰熔融温度降低.FactSage计算表明生成含Na矿物质反应的ΔG较小, 其在高温下更容易发生.
利用XRD和FT-IR考察了高温弱还原气氛下Na2O对两种硅铝含量不同的煤灰中矿物质组成的影响, 揭示了Na2O影响煤灰熔融特性的本质.通过FactSage计算了高温下矿物质反应的ΔG, 探讨了Na2O影响煤灰中矿物质组成的机理.结果表明, Na2O对煤灰矿物质组成的影响与原煤灰的硅铝含量密切相关.硅铝总含量82.89%的煤灰, Na2O含量为5%-20%时, 钠长石和霞石的生成是煤灰熔融温度降低的主要原因; 当Na2O含量大于20%时, 导致煤灰熔融温度降低的原因是霞石的生成.硅铝总含量47.85%的煤灰, Na2O含量小于10%时, 没有含钠矿物质生成; 当Na2O含量大于10%时, 主要生成菱硅钙钠石、青金石和含钠的硅铝酸盐矿物, 导致煤灰熔融温度降低.FactSage计算表明生成含Na矿物质反应的ΔG较小, 其在高温下更容易发生.
2016, 44(7): 801-814.
摘要:
合成气直接催化转化制备低碳烯烃是C1化学与化工领域中一个极具挑战性的研究课题, 具有流程短、能耗低等优势, 已成为非石油路径生产烯烃的新途径。直接转化方式主要包括经由OX-ZEO双功能催化剂直接制低碳烯烃的双功能催化路线以及经由费托反应直接制备低碳烯烃的FTO路线。综述简述了近年来在合成气直接制备低碳烯烃方面的研究进展, 重点讨论了低碳烯烃的形成机理、新型催化剂的研发及助剂对其催化性能的影响, 并对合成气直接制烯烃的未来进行了展望。
合成气直接催化转化制备低碳烯烃是C1化学与化工领域中一个极具挑战性的研究课题, 具有流程短、能耗低等优势, 已成为非石油路径生产烯烃的新途径。直接转化方式主要包括经由OX-ZEO双功能催化剂直接制低碳烯烃的双功能催化路线以及经由费托反应直接制备低碳烯烃的FTO路线。综述简述了近年来在合成气直接制备低碳烯烃方面的研究进展, 重点讨论了低碳烯烃的形成机理、新型催化剂的研发及助剂对其催化性能的影响, 并对合成气直接制烯烃的未来进行了展望。
2020, 48(11): 1281-1297.
摘要:
煤炭是中国重要的能源资源,而中国煤中重金属砷、硒、铅含量较高,燃煤电厂已经成为重要的砷、硒、铅排放源之一。针对电厂燃煤带来严峻的砷、硒、铅污染问题,本文首先介绍了燃煤释放的砷、硒、铅排放量大且危害性强,概述了世界各国关于重金属排放控制的相关政策法规,指出中国对燃煤重金属砷、硒、铅的排放控制势在必行;其次从煤中赋存形态、燃烧过程中的形态转化和质量分布三个方面阐释了燃煤过程中砷、硒、铅的迁移转化规律,重点描述了砷、硒、铅在颗粒物上的形态特征和尺度分布;最后综述了燃烧前、燃烧中和燃烧后对砷、硒、铅的排放控制技术,详述了吸附剂捕集和烟气净化装置协同脱除的研究进展,并论述了低低温除尘器和团聚技术对砷、硒、铅的强化脱除潜力。以期为燃煤电厂重金属砷、硒、铅超低排放的实现提供参考和指导。
煤炭是中国重要的能源资源,而中国煤中重金属砷、硒、铅含量较高,燃煤电厂已经成为重要的砷、硒、铅排放源之一。针对电厂燃煤带来严峻的砷、硒、铅污染问题,本文首先介绍了燃煤释放的砷、硒、铅排放量大且危害性强,概述了世界各国关于重金属排放控制的相关政策法规,指出中国对燃煤重金属砷、硒、铅的排放控制势在必行;其次从煤中赋存形态、燃烧过程中的形态转化和质量分布三个方面阐释了燃煤过程中砷、硒、铅的迁移转化规律,重点描述了砷、硒、铅在颗粒物上的形态特征和尺度分布;最后综述了燃烧前、燃烧中和燃烧后对砷、硒、铅的排放控制技术,详述了吸附剂捕集和烟气净化装置协同脱除的研究进展,并论述了低低温除尘器和团聚技术对砷、硒、铅的强化脱除潜力。以期为燃煤电厂重金属砷、硒、铅超低排放的实现提供参考和指导。
2016, 44(11): 1388-1393.
摘要:
分别以β、ZSM-5和USY分子筛为载体,采用浸渍法制备了锰铈催化剂,对其低温NH3-SCR反应性能进行了评价,并采用XRD、BET、NH3-TPD、H2-TPR以及XPS对催化剂进行了表征。结果表明,三种分子筛负载的锰铈催化剂均具有较好的低温NH3-SCR反应活性,其中,Mn-Ce/USY的催化性能最好,在107℃时NOx转化率可达到90%。负载锰铈后催化剂的比表面积和孔体积均有所下降;活性组分MnOx主要以无定型态分布于催化剂表面,且在ZSM-5上检测到聚集的CeO2。催化剂表面弱酸对低温NH3-SCR反应起主要作用,催化剂表面上活性组分的表面浓度和氧化态明显不同,较高的Mn4+/Mn3+原子比和吸附氧表面浓度对提高催化剂的低温NH3-SCR反应活性有利。
分别以β、ZSM-5和USY分子筛为载体,采用浸渍法制备了锰铈催化剂,对其低温NH3-SCR反应性能进行了评价,并采用XRD、BET、NH3-TPD、H2-TPR以及XPS对催化剂进行了表征。结果表明,三种分子筛负载的锰铈催化剂均具有较好的低温NH3-SCR反应活性,其中,Mn-Ce/USY的催化性能最好,在107℃时NOx转化率可达到90%。负载锰铈后催化剂的比表面积和孔体积均有所下降;活性组分MnOx主要以无定型态分布于催化剂表面,且在ZSM-5上检测到聚集的CeO2。催化剂表面弱酸对低温NH3-SCR反应起主要作用,催化剂表面上活性组分的表面浓度和氧化态明显不同,较高的Mn4+/Mn3+原子比和吸附氧表面浓度对提高催化剂的低温NH3-SCR反应活性有利。
2016, 44(9): 1034-1042.
摘要:
通过在一种真实煤灰中添加不同的氧化物或直接用氧化物配制合成灰,探究了不同灰成分对灰熔融特性的影响规律。利用FactSage 7.0对不同灰分的熔融过程进行了热力学模拟,通过熔融过程中的矿物质变化为各种灰成分对熔融特性的影响规律提供理论依据。结果表明,氧化钠对灰熔点的降低作用源于钠长石和霞石对钙长石的取代;氧化镁含量的增加对灰熔点起先降低后升高的作用,当氧化镁含量超过一定时,产生的镁橄榄石能够升高灰熔点;硫对灰熔点的升高作用源于镁橄榄石和硫酸钙对透辉石的取代;氧化钙含量的增加对灰熔点起到先降低后升高的作用,当氧化钙含量超过一定时,硅从熔点较低的矿物质迁移到熔点较高的矿物质中,升高了灰熔点。在与硅氧单元体结合的过程中,氧化钠优先于氧化钙;与氧化钙和硅氧单元体结合的氧化物的优先级为:氧化铝>氧化镁>氧化铁。
通过在一种真实煤灰中添加不同的氧化物或直接用氧化物配制合成灰,探究了不同灰成分对灰熔融特性的影响规律。利用FactSage 7.0对不同灰分的熔融过程进行了热力学模拟,通过熔融过程中的矿物质变化为各种灰成分对熔融特性的影响规律提供理论依据。结果表明,氧化钠对灰熔点的降低作用源于钠长石和霞石对钙长石的取代;氧化镁含量的增加对灰熔点起先降低后升高的作用,当氧化镁含量超过一定时,产生的镁橄榄石能够升高灰熔点;硫对灰熔点的升高作用源于镁橄榄石和硫酸钙对透辉石的取代;氧化钙含量的增加对灰熔点起到先降低后升高的作用,当氧化钙含量超过一定时,硅从熔点较低的矿物质迁移到熔点较高的矿物质中,升高了灰熔点。在与硅氧单元体结合的过程中,氧化钠优先于氧化钙;与氧化钙和硅氧单元体结合的氧化物的优先级为:氧化铝>氧化镁>氧化铁。
2018, 46(2): 179-188.
摘要:
采用原位合成法在γ-Al2O3表面合成了锌铝水滑石,再通过顺次浸渍法制备了一系列掺杂稀土改性的M(M=Y、La、Ce、Sm、Gd)/Cu/ZnAl催化材料,并将其应用于甲醇水蒸气重整制氢反应。探讨了稀土掺杂改性对Cu/ZnAl催化剂催化性能的影响,并采用XRD、SEM-EDS、BET、H2-TPR、XPS和N2O滴定等手段对催化剂进行了表征。结果表明,催化剂的活性与Cu比表面积和催化剂的还原性质密切相关,Cu比表面积越大,还原温度越低,催化活性越高。稀土Ce、Sm、Gd的引入能改善活性组分Cu的分散度、Cu比表面积以及催化剂的还原性质,进而提高催化剂的催化活性。其中,Ce/Cu/ZnAl催化剂表现出最佳的催化活性,在反应温度为250 ℃时,甲醇转化率达到100%,CO含量为0.39%,相比Cu/ZnAl催化剂,甲醇转化率提高了近40%。
采用原位合成法在γ-Al2O3表面合成了锌铝水滑石,再通过顺次浸渍法制备了一系列掺杂稀土改性的M(M=Y、La、Ce、Sm、Gd)/Cu/ZnAl催化材料,并将其应用于甲醇水蒸气重整制氢反应。探讨了稀土掺杂改性对Cu/ZnAl催化剂催化性能的影响,并采用XRD、SEM-EDS、BET、H2-TPR、XPS和N2O滴定等手段对催化剂进行了表征。结果表明,催化剂的活性与Cu比表面积和催化剂的还原性质密切相关,Cu比表面积越大,还原温度越低,催化活性越高。稀土Ce、Sm、Gd的引入能改善活性组分Cu的分散度、Cu比表面积以及催化剂的还原性质,进而提高催化剂的催化活性。其中,Ce/Cu/ZnAl催化剂表现出最佳的催化活性,在反应温度为250 ℃时,甲醇转化率达到100%,CO含量为0.39%,相比Cu/ZnAl催化剂,甲醇转化率提高了近40%。
2018, 46(1): 92-98.
摘要:
通过建立具有更精确的SO3组分的实验室模拟烟气系统,同步研究了反应物浓度对硫酸氢铵和硫酸铵生成率和生成进度(生成速率)的影响。在实验浓度范围内,硫酸氢铵的开始生成温度为230-270℃,峰值温度为180-240℃,硫酸铵开始生成温度及峰值温度总体上比硫酸氢铵低40℃左右。硫酸氢铵的生成率明显高于硫酸铵,根据NH3和SO3浓度与物质的量比不同,烟温到120℃时,硫酸氢铵的生成率为64%-90%,硫酸铵的生成率为6%-15%,硫酸氢铵的生成率为硫酸铵的6-10倍。反应物浓度的增加会促进硫酸氢铵和硫酸铵的生成,且SO3较NH3更有利于硫酸氢铵的生成。硫酸氢铵和硫酸铵生成份额随温度的变化呈单峰状,且随着反应物浓度的增加,其峰值所在的温度区间逐渐升高。
通过建立具有更精确的SO3组分的实验室模拟烟气系统,同步研究了反应物浓度对硫酸氢铵和硫酸铵生成率和生成进度(生成速率)的影响。在实验浓度范围内,硫酸氢铵的开始生成温度为230-270℃,峰值温度为180-240℃,硫酸铵开始生成温度及峰值温度总体上比硫酸氢铵低40℃左右。硫酸氢铵的生成率明显高于硫酸铵,根据NH3和SO3浓度与物质的量比不同,烟温到120℃时,硫酸氢铵的生成率为64%-90%,硫酸铵的生成率为6%-15%,硫酸氢铵的生成率为硫酸铵的6-10倍。反应物浓度的增加会促进硫酸氢铵和硫酸铵的生成,且SO3较NH3更有利于硫酸氢铵的生成。硫酸氢铵和硫酸铵生成份额随温度的变化呈单峰状,且随着反应物浓度的增加,其峰值所在的温度区间逐渐升高。
2013, 41(08): 1003-1009.
Abstract:
2009, 37(04): 501-505.
Abstract: