Economic Evaluation of Post-Combustion CO2 Capture Integration Technology in Natural Gas Combined Cycle Power Plant

[Introduction] In recent years, natural gas power generation has played an important role in the construction of clean energy system of China. By the end of the "14th Five-year Plan" in 2025, China's gas power installed capacity is expected to hit 150 million kilowatts. Carbon capture，utilization and storage (CCUS) is one of the key paths for gas power to achieve the carbon peaking and carbon neutrality goals. [Method] To this end, an integrated plant combining 600 MW natural gas combined cycle (NGCC) and CO2 post-combustion capture (PCC) were set up as the simulation object. [Result] The simulation study shows that the design captures all CO2 flue gas with 90% efficiency, the CO2 compression and purification rate is 99.5%, the total output of gas power generation decreases by about 16.05%, the auxiliary power ratio increases by 5.55%, and the demand for circulating cooling water increases by about 50.52%. [Conclusion] The economic analysis shows that the static investment cost of the integrated plant is 54.28% higher than that of the single power plant, and the levelized cost of energy (LCOE) increases by 15.96%, which brings great difficulties to the deployment and development of carbon dioxide capture. However, the natural gas price is still the most important factor affecting the operating cost of the power plant

Insights into the Role of Nanorod-Shaped MnO2 and CeO2 in a Plasma Catalysis System for Methanol Oxidation

Published papers highlight the roles of the catalysts in plasma catalysis systems, and it is essential to provide deep insight into the mechanism of the reaction. In this work, a coaxial dielectric barrier discharge (DBD) reactor packed with γ-MnO2 and CeO2 with similar nanorod morphologies and particle sizes was used for methanol oxidation at atmospheric pressure and room temperature. The experimental results showed that both γ-MnO2 and CeO2 exhibited good performance in methanol conversion (up to 100%), but the CO2 selectivity of CeO2 (up to 59.3%) was much higher than that of γ-MnO2 (up to 28.6%). Catalyst characterization results indicated that CeO2 contained more surface-active oxygen species, adsorbed more methanol and utilized more plasma-induced active species than γ-MnO2. In addition, in situ Raman spectroscopy and Fourier transform infrared spectroscopy (FT-IR) were applied with a novel in situ cell to reveal the major factors affecting the catalytic performance in methanol oxidation. More reactive oxygen species (O22−, O2−) from ozone decomposition were produced on CeO2 compared with γ-MnO2, and less of the intermediate product formate accumulated on the CeO2. The combined results showed that CeO2 was a more effective catalyst than γ-MnO2 for methanol oxidation in the plasma catalysis system.</jats:p

Unlocking High-Efficiency Methane Oxidation with Bimetallic Pd–Ce Catalysts under Zeolite Confinement

Catalytic complete oxidation is an efficient approach to reducing methane emissions, a significant contributor to global warming. This approach requires active catalysts that are highly resistant to sintering and water vapor. In this work, we demonstrate that Pd nanoparticles confined within silicalite-1 zeolites (Pd@S-1), fabricated using a facile in situ encapsulation strategy, are highly active and stable in catalyzing methane oxidation and are superior to those supported on the S-1 surface due to a confinement effect. The activity of the confined Pd catalysts was further improved by co-confining a suitable amount of Ce within the S-1 zeolite (PdCe0.4@S-1), which is attributed to confinement-reinforced Pd-Ce interactions that promote the formation of oxygen vacancies and highly reactive oxygen species. Furthermore, the introduction of Ce improves the hydrophobicity of the S-1 zeolite and, by forming Pd-Ce mixed oxides, inhibits the transformation of the active PdO phase to inactive Pd(OH)2 species. Overall, the bimetallic PdCe0.4@S-1 catalyst delivers exceptional outstanding activity and durability in complete methane oxidation, even in the presence of water vapor. This study may provide new prospects for the rational design of high-performance and durable Pd catalysts for complete methane oxidation

Plasma-Catalytic CO₂ Hydrogenation over a Pd/ZnO Catalyst: <i>In Situ</i> Probing of Gas-Phase and Surface Reactions

Plasma-catalytic CO2 hydrogenation is a complex chemical process combining plasma-assisted gas-phase and surface reactions. Herein, we investigated CO2 hydrogenation over Pd/ZnO and ZnO in a tubular dielectric barrier discharge (DBD) reactor at ambient pressure. Compared to the CO2 hydrogenation using Plasma Only or Plasma + ZnO, placing Pd/ZnO in the DBD almost doubled the conversion of CO2 (36.7%) and CO yield (35.5%). The reaction pathways in the plasma-enhanced catalytic hydrogenation of CO2 were investigated by in situ Fourier transform infrared (FTIR) spectroscopy using a novel integrated in situ DBD/FTIR gas cell reactor, combined with online mass spectrometry (MS) analysis, kinetic analysis, and emission spectroscopic measurements. In plasma CO2 hydrogenation over Pd/ZnO, the hydrogenation of adsorbed surface CO2 on Pd/ZnO is the dominant reaction route for the enhanced CO2 conversion, which can be ascribed to the generation of a ZnO x overlay as a result of the strong metal-support interactions (SMSI) at the Pd-ZnO interface and the presence of abundant H species at the surface of Pd/ZnO; however, this important surface reaction can be limited in the Plasma + ZnO system due to a lack of active H species present on the ZnO surface and the absence of the SMSI. Instead, CO2 splitting to CO, both in the plasma gas phase and on the surface of ZnO, is believed to make an important contribution to the conversion of CO2 in the Plasma + ZnO system

Performance of a Novel Hydrophobic Mesoporous Material for High Temperature Catalytic Oxidation of Naphthalene

A high surface area, hydrophobic mesoporous material, MFS, has been successfully synthesized by a hydrothermal synthesis method using a perfluorinated surfactant, SURFLON S-386, as the single template. N2 adsorption and TEM were employed to characterize the pore structure and morphology of MFS. Static water adsorption test indicates that the hydrophobicity of MFS is significantly higher than that of MCM-41. XPS and Py-GC/MS analysis confirmed the existence of perfluoroalkyl groups in MFS which led to its high hydrophobicity. MFS was used as a support for CuO in experiments of catalytic combustion of naphthalene, where it showed a significant advantage over MCM-41 and ZSM-5. SEM was helpful in understanding why CuO-MFS performed so well in the catalytic combustion of naphthalene. Experimental results indicated that MFS was a suitable support for catalytic combustion of large molecular organic compounds, especially for some high temperature catalytic reactions when water vapor was present

Synthesis of Hydrophobic Mesoporous Material MFS and Its Adsorption Properties of Water Vapor

Fluorine-containing hydrophobic mesoporous material (MFS) with high surface area is successfully synthesized with hydrothermal synthesis method by using a perfluorinated surfactant SURFLON S-386 template. The adsorption properties of water vapor on the synthesized MFS are also investigated by using gravimetric method. Results show that SEM image of the MFS depicted roundish morphology with the average crystal size of 1-2 μm. The BET surface area and total pore volume of the MFS are 865.4 m2 g−1 and 0.74 cm3 g−1 with a narrow pore size distribution at 4.9 nm. The amount of water vapor on the MFS is about 0.41 mmol g−1 at 303 K, which is only 52.6% and 55.4% of MCM-41 and SBA-15 under the similar conditions, separately. The isosteric adsorption heat of water on the MFS is gradually about 27.0–19.8 kJ mol−1, which decreases as the absorbed water vapor amount increases. The value is much smaller than that on MCM-41 and SBA-15. Therefore, the MFS shows more hydrophobic surface properties than the MCM-41 and SBA-15. It may be a kind of good candidate for adsorption of large molecule and catalyst carrier with high moisture resistance

Removal Of Gas Phase Dimethylamine And N,N-Dimethylformamide Using Non-Thermal Plasma

Dimethylamine (DMA) and N,N-dimethylformamide (DMF) are typical N-VOCs exhausted from manufacturing factories. In the present study, the behavior of non-thermal plasma (NTP) was systematically investigated for removal of gas-phase DMA and DMF in a link tooth wheel-cylinder plasma reactor. Experimental results show that DMA is much easier to be decomposed by NTP than DMF. On the other hand, coexisting DMF has no effect on DMA conversion while DMF conversion is significantly promoted by the addition of DMA. It is also found that regardless of initial gas compositions as well as DMA and DMF concentration, COx selectivity increased monotonously with increasing ED. But COx selectivity of 100% cannot be obtained even with ED higher than 70 J L-1, indicating the formation of organic intermediates during DMA and DMF decomposition. Based on organic products analysis with GC-MS and molecule optimization results with density functional theory calculation, possible mechanisms on DMA and DMF degradation were proposed. On the other hand, the organic products from DMA and DMF decomposition by NTP were found to have great solubility and high biodegradability. Thus, NTP enhanced absorption/biological method is suggested for complete removal of DMA and DMF

A computational study on the hydrogenation of CO2 catalyzed by a tetraphos-ligated cobalt complex: monohydride vs. dihydride

Density functional theory (DFT) calculations were used to study the mechanisms of hydrogenation of carbon dioxide catalyzed by the tetraphos-ligated (PP3: P.CH2CH2PPh2)(3)) cobalt complexes. We investigated the binding modes between CO2 and the cobalt metal center to determine whether the CO2 coordinated to the metal center in the catalytic processes. The monohydride catalytic pathway (Path I) and the dihydride catalytic pathway (Path II) for the hydrogenation of CO2 have been explored. In these two cases, a weak H. CO2 interaction leads to cleavage of the Co-H bond and subsequent formation of the formate ligand. Moreover, the transformation from the dihydride to the monohydride is endergonic by 9.2 kcal mol(-1) and the relevant free energy barrier is about 20.9 kcal mol(-1). However, the largest free energy barrier of 19.1 kcal mol(-1) in Path II is significantly lower than that in Path I (22.8 kcal mol(-1)), which corresponds to the hydride transfer from the cobalt center to CO2. The detailed comparisons of the possible pathways suggest that Path II is much more favoured than Path I and that it is not necessary to form the monohydride species in the whole catalytic cycle. Our results, which unambiguously demonstrate that the active catalyst is the dihydride rather than the monohydride, are consistent with the experimental observations and, most importantly, provide detailed mechanistic insight

Performance of Toluene Removal in a Nonthermal Plasma Catalysis System over Flake-Like HZSM-5 Zeolite with Tunable Pore Size and Evaluation of Its Byproducts

In this study, a series of HZSM-5 catalysts were prepared by the chemical liquid-phase deposition method, and low concentration toluene degradation was carried out in an atmospheric pressure dielectric barrier discharge (DBD) reactor. The catalysts were characterized by X-ray powder diffraction (XRD), SEM, TEM, and N2 adsorption analysis techniques. In addition, several organic contaminants were used to evaluate the adsorption performance of the prepared catalysts, and the effect of pore size on the removal efficiency of toluene and byproduct formation was also investigated. The unmodified HZSM-5 zeolite (Z0) exhibited good performance in toluene removal and CO2 selectivity due to the diffusion resistance of ozone and the amounts of active species (OH• and O•). Meanwhile, the time of flight mass spectrometry (TOF-MS) result showed that there were more byproducts of the benzene ring in the gas phase under the action of small micropore size catalysts. Moreover, the surface byproducts were detected by gas chromatography–mass spectrometry (GC-MS)

Amine-functionalized metal-organic frameworks for the transesterification of triglycerides

For the application of functionalized metal-organic frameworks (MOFs) as a solid base, amine-functionalized MOF materials are achieved by (i) dative modification of unsaturated metal sites located at the secondary building units of MOFs with diamine, and (ii) covalent modification of the amine-tagged organic linkers within the MOF by alkylation with 2-dimethylaminoethyl chloride. The resulting amine-functionalized MOFs exhibit excellent results in the liquid phase transesterification of triglycerides and methanol, with the triglyceride conversions exceeding 99%, which are important model reactions for the production of biodiesel. The relationship between the catalytic activity towards transesterification and the basicity of amine-functionalized MOFs reveals a linear correspondence in terms of turnover frequency and basic site density. The basicity of the MOFs and reaction parameters are shown to significantly affect the catalytic performance. Kinetics studies reveal that the reaction follows first-order kinetics with the calculated activation energy of 48.2 kJ mol(-1). This research opens up new perspectives on the postsynthetic modification of MOFs and more generally on the rational design of MOF-derived solid base catalysts