In this study, two-dimensional CFD simulation model is developed for investigating the hydrogen separation process across the Pd-membrane type. The influences of H2 feeding flow rate and membrane thickness on the hydrogen permeation process were investigated. Also, two Pd-membrane thicknesses of 15μm and 20μm were investigated to understand the hydrogen embrittlement and diffusion through membrane. The numerical model parameters was adjusted at a reactor temperature of 150 :C and feed pressure of 100 kPa. The velocity, concentration, and diffusion mass transfer flux distribution were numerically achieved by the model. The simulation results showed that the hydrogen velocity distribution increased with the feeding gas flow rate. Furthermore, the diffusion flux was enhanced with the permeation time and the feeding flow rate increased. It can be concluded that the hydrogen concentration and diffusion mass transfer flux through thick membranes was low compared with lower membrane thickness. It can be expected that the CFD simulation model will aid in the membrane separation design, selection and development.
The development of photovoltaic industry can effectively alleviate the energy crisis and environmental pollution. The deployment of photovoltaic power stations along the high-speed railway is a new mode combining photovoltaic new energy with infrastructure. This paper constructs a comprehensive decision-making framework for the site selection of PV power station along high-speed railway combining the subjective method and the objective method. A scientific and reasonable evaluation index system comprehensively considering multiple factors is constructed in this framework. Analytic hierarchy process and Entropy weight method are combined to determine the weight of every index, which combines the expert knowledge and data information effectively, relatively reducing systematic error and random error. Grey relational analysis is used to choose scheme among several alternatives, which greatly deal with the strong grey correlations among indexes. The framework established in this paper is used to select PV power stations along the Beijing-Shanghai high-speed railway, which also verifies the effectiveness of the framework.
Under the strategic goal of “peak carbon dioxide emissions and carbon neutrality” in China, industries with high energy consumption and high pollution, such as iron and steel plants, are facing great pressure of energy conservation and emission reduction, and are in urgent need of green and low-carbon transformation. In this paper, 46 iron and steel plants in Hebei province are taken as examples. GIS spatial analysis and environmental emission list method are used to build a comprehensive evaluation model of rooftop photovoltaic, and to calculate the technical potential, energy saving and emission reduction benefits and economic feasibility of deploying rooftop photovoltaic in iron and steel plants. Finally, carbon trading mechanism is introduced to analyze its impact on the carbon trading market. It is found that 46 iron and steel plants save 216,700 tons of standard coal, reduce 144,700 tons of CO2 emissions and reduce 1,500 tons of SO2, NOX, PM and other air pollutants every year. The economic benefit of power generation self-use mode is greater than that of grid-fed mode, with an average return on investment of 140% and a payback period of 5.5 years. The results verify that rooftop photovoltaic in iron and steel plants has dual benefits of energy saving and emission reduction and economy, and this data can provide a feasible path for iron and steel plants to use photovoltaic for green and low-carbon transformation.