We studied the effects of peak temperature and cooling rate in the secondary welding thermal cycles on the martensite/austenite (M/A) constituents’ characteristics (including fraction, average size and distribution), corrosion resistance and hydrogen permeation behaviors in the inter-critically reheated coarse-grained heat-affected zone (ICCGHAZ) of X80 pipeline steel. We observed that the M/A constituents’ characteristics mainly depend on the secondary peak temperature and cooling rates, while the microstructure style and prior austenite grain size are dependent on the first peak temperature. In addition, the variations in the M/A constituents’ characteristics result in different corrosion resistance and hydrogen permeation behaviors by changing the micro-galvanic effect and the number of hydrogen trapping sites. The high fraction and coarse grain size of M/A constituents are against the corrosion resistance and hydrogen permeation in ICCGHAZs, and their functional relationships are established. Moreover, the effects of the fraction of M/A constituents on the corrosion resistance and hydrogen permeation behaviors are much greater than those of the average size.

In this study, a novel system which integrates solar thermal energy with membrane gas absorption technology is proposed to capture CO₂ from a 580 MWe pulverized coal power plant. Technical feasibility and economic evaluation are carried out on the proposed system in three cities with different solar resources in China. Research results show that the output capacity and net efficiency of the SOL-HFMC power plant are significantly higher than those of the reference power plant regardless of whether a TES system is applied or not. In addition, the CEI of the SOL-HFMC power plant with the TES system is 4.36 kg CO₂/MWh, 4.45 kg CO₂/MWh and 4.66 kg CO₂/MWh lower than that of the reference power plant. The prices of the membrane, vacuum tube collector and phase change material should be reduced to achieve lower LCOE and COR values. Specifically for the SOL-HFMC power plant with the TES system, the corresponding vacuum tube collector price shall be lower than 25.70 $/m² for Jinan, 95.20 $/m² for Xining, and 128.70 $/m² for Lhasa, respectively. To be more competitive than a solar-assisted ammonia-based post-combustion CO₂ capture power plant, the membrane price in Jinan, Xining and Lhasa shall be reduced to 0.012 $/m, 0.015 $/m and 0.016 $/m for the sake of LCOE, and 0.03 $/m, 0.033 $/m and 0.034 $/m for the sake of COR, respectively.

By optimising the particle size of cladding alloy powders, in situ micron and submicron (Ti-V)C reinforced Fe-based laser cladding layers were prepared and the dry sliding friction properties were comparatively studied. Results showed that there were same phases of α-Fe, γ, TiC, and TiVC₂ in the two cladding layers. The average grain size of the Fe-based matrix was 3.46 μm and 3.37 μm, the microhardness was 731 HV0.2 and 736 HV0.2, and the area ratio of carbides was 11.14% and 11.02%, respectively. The dry sliding wear resistance of the cladding layer reinforced by 1.95 μm carbides was 2.76 times higher than that of the 0.49 μm carbides. The failure mechanism of the cladding layer with the micron carbides was mainly caused by plastic deformation of the cladding layer matrix, whereas that of the submicron carbides involved both the plastic deformation of the cladding layer matrix and the abrasion that was caused by the peeled carbides.

Membrane gas absorption technology has been considered a promising approach to mitigate CO₂ emissions from power plants. The aim of this study is to evaluate the environmental impacts of CO₂ absorption and desorption processes by hollow fiber membrane contactors using a life cycle assessment methodology. On the basis of the ReCipe 2016 Midpoint and the ReCipe 2016 Endpoint methods, the research results show that membrane gas absorption systems exhibit the lowest environmental impacts across the majority of assessed categories in comparison with chemical absorption and membrane gas separation systems. The CO₂ capture process via membrane gas absorption has the most significant impact on the METP category, with heat consumption as the primary contributing factor accounting for 55%, followed by electricity consumption accounting for 43.1%. According to the sensitivity analysis, heating by natural gas shows better performance than other heat supply sources in improving overall environmental impacts. In addition, the increasing utilization of renewable energy in electricity supply reduces the global warming potential, fossil resource consumption and ozone formation.