Study On Purification Of Hydrogen For Fuel Cells By Pressure Swing Adsorption

The rapid economic and social development has raised people’s awareness of environmental protection,and the shipping industry is also facing increasing pressure to reduce ship emissions and protect the environment.Ships,as the main means of transportation for bulk cargoes,still use fossil fuels such as heavy oil as the main fuel.On the one hand,the International Maritime Organization(IMO)has established strict ship gas emission standards through MARPOL Annex VI;on the other hand,traditional ships that use heavy oil as the main fuel still cannot meet this emission standard in a short time.Hydrogen-oxygen fuel cells use hydrogen as the main fuel,which can not only realize the high power output requirements of ships through modular adjustment of power,but also provide the application potential for fuel cell ships due to the clean and environmental advantages of only discharging water by consuming hydrogen and oxygen.However,as a transportation vehicle,the storage and carrying of hydrogen is a key problem for the application of fuel cell ships.Natural gas,is a traditional shipborne cargo.Using natural gas to produce hydrogen on-site on ships is a potential solution.However,in addition to containing about 75%-80%(volume percent)H2 in the on-site hydrogen reforming gas of natural gas,there are also impurity gases such as C02,CO,CH4 and N2.The pressure swing adsorption process has a short cycle period,high adsorbent utilization efficiency,and relatively small amount of adsorbent.It does not require external heat exchange equipment and is widely used for the separation and purification of atmospheric component gases.Therefore,it is proposed to apply pressure swing adsorption technology to reformed hydrogen purification.In order to explore its feasibility,this paper has carried out the research on PSA purification technology,mainly carried out the following research work on PSA adsorbent and PSA process:(1)First,the static adsorption experiment of the single-component gas of the adsorbent was carried out,the equilibrium parameters of the Dual-Site Langmuir adsorption model were fitted with Origin data processing software,and the adsorption performance of the adsorbent was discussed,and the gas of each component was obtained Heat of adsorption.(2)Secondly,experiments and simulations of single-component dynamic breakthrough curves of different gases were carried out,the adsorption performance of various components on different adsorbents was compared,and the heat transfer coefficient and other related parameters were obtained through experimental verification of the simulation results.PSA simulation provides data and theoretical support.(3)Again,according to the ten-tower pressure swing adsorption device,the experiment of pressure swing adsorption and purification of hydrogen was carried out,and the process was simulated using Aspen plus software,and the simulation results were compared with the experimental results to verify the simulation The accuracy of the procedure.(4)Finally,a 10-tower pressure swing simulation study was carried out on the adsorption time,regeneration time and pressure equalization steps.The product gas content was analyzed by changing the parameters and operation timing,and the hydrogen purity and hydrogen recovery rate were the main indicators,The operation steps of PSA were analyzed.The research results show that:under the same adsorption pressure,keeping the other operating parameters the same,increasing the raw gas processing capacity will reduce the purity of the raw gas,and can improve the recovery rate of hydrogen products.In the process of high pressure,the product recovery rate is 80%,and the product hydrogen meets the standard of fuel cell ships.The standard methane reforming product gas is used as the raw material gas,and the 10-tower pressure swing adsorption process is used.The product recovery rate is 80%,and the product gas hydrogen purity is>99.99%.