The performance of membrane humidifier (MH) and enthalpy wheel humidifier (EWH) for a large power proton exchange membrane fuel cell (PEMFC) system is compared using simulations and experiments. The MH model is based on one dimensional diffusion equation and the EWH model is based on the porous media surface diffusion equation. Simulation results agree well with experimental data. According to the results, the effect of intake air temperature has a lower effect on the MH performance than it does on the EWH performance while the air mass flow has a much higher effect on the MH performance than it does on the EWH performance. MH performs better than EWH at a low flow rate but worse at a high flow rate. Vapor transfer mechanism in the humidifiers is also studied.
This paper introduces a new type of toxic and harmful gas analyzer based on DOAS (differential optical absorption spectroscopy) technology. Combined with the least square method, it can monitor H2S, NH3, SO2, NO2 and CH3SH online at the same time, and the prescribed minimum is as low as 0.1ppb, the detection breadth and accuracy are higher than those of the current common DOAS instruments.
Vegetable oil-based hydraulic oil is one of the biodegradable lubricants. With the strengthening of environmental awareness, especially in the context of the increasingly serious pollution of the marine environment by mineral oil used in ships, people are increasingly aware that the pollution of mineral oil-based hydraulic oil to the environment is very serious, and many solutions have been proposed. The use of biodegradable plant-based hydraulic oil instead of traditional mineral oil-based hydraulic oil can fundamentally solve the pollution of marine hydraulic oil to the marine environment. The development of vegetable oil-based hydraulic oil in the world is systematically summarized, including its material composition, physical and chemical properties. By analysing its practical prospect and future development direction, it is concluded that vegetable oil-based hydraulic oil is the most environmentally friendly hydraulic oil in the future shipbuilding, industrial manufacturing and other industries, and it is the development trend of “green shipping” in China in the future.
Diesel particulate filters is the most effective post-treatment device used to reduce diesel exhaust particulate emissions. As the amount of particulate matter captured in the diesel particulate filter continues to increase, the exhaust pressure of the diesel engine gradually increases, thereby affecting the power performance of the diesel engine. Therefore, when the particulate matter capture amount reaches a certain value, the diesel particulate matter filter needs to be regenerated. Regeneration of diesel particulate filters will produce secondary pollution, of which CO is one of the most important secondary pollution. In this paper, the CO generation mechanism and influencing factors in the regeneration process of diesel particulate filters are analyzed. The effects of exhaust pressure and exhaust flow on CO emission during regeneration are measured through experiments. The results show that when the exhaust back pressure is greater than 80kPa, the CO solubility in the exhaust gas increases rapidly, and decreases linearly with the increase of exhaust flow during regeneration. Therefore, in order to reduce the solubility of CO in tail gas during regeneration of diesel particulate filters, the exhaust back pressure shall be less than 80kPa and the exhaust flow shall be as high as possible.
This paper describes the technical characteristics and application status of ANITAII (Analysing Interferometer for Ambient Air), an atmospheric monitoring system currently used by ESA (European Space Agency), reveals the characteristics and advantages of FTIR (Fourier transform infrared spectroscopy) technology in multi-component gas monitoring, and analyzes the application prospect of FTIR technology in the field of environmental monitoring.
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