Study On The Performance Of Humic Acid Doped Magnesis And Ite Supported Ru-Based Catalysts For Ammonia Synthesis

The article was focused on the modification of Ba-MgO by humic acid,and a series of Ba-MgO supports and its supported Ru-based catalysts for ammonia synthesis were prepared by chemical precipition-strong electrical adsorption?SEA?method with the aid of ultrasonic wave and impregnation method,respectively.The effect of different humic acid,addition amount,addition method and preparation conditions,including pH value of precipitation solution,calcination temperature,ultrasonic time and reduction temperature,on the supports and catalysts were investigated by XRD?FE-SEM?EDS?BET?H₂-TPR and FT-IR,etc.The main research contents and results were as follows:1?The chemical composition and structure were similar,but the amount of hydroxyl and carboxyl of HA2 and HA3 was more than the amount of HA1.And they interacted with Mg²⁺and Ba²⁺to influence the adsorbing capacity of Ba²⁺when the Ba-MgO supports were doped with HA.The doping amount of Ba of Ba-MgO-HA3was more than Ba-MgO-HA1 and Ba-MgO-HA2.In the range of experiment,when the Ba-MgO support doped with HA3,the outlet of ammonia concentration of Ru/Ba-MgO-2wt%HA3 is 15.14%under the reaction conditions of 10MPa,425°C and 10000h^-1.2?The doping method and doping amount of HA can influenced the amount of Ba.The amount of Ba increased with increasing the doping amount HA and reached a maximum value before declined when HA3 was added to Ba-MgO supports by once addition method.And in the range of experiment,when the addition amount of HA3was 2wt%,the outlet of ammonia concentration of Ru/Ba-MgO-2wt%HA3 is 15.14%under the reaction conditions of 10MPa,425°C and 10000h^-1.3?The catalytic activity were influenced by pH value of precipitation solution,calcination temperature,ultrasonic time and reduction temperature;?1?The pH value of precipitation solution can influence the doping amount of Ba and the specific surface area.And the doping amount of Ba and the specific surface area of supports decreased with increasing the pH value of precipitation solution;?2?The calcination temperature can influence the doping amount of Ba,the specific surface area and the size of Ru particle.The doping amount of Ba increased with increasing the calcination temperature and reached a maximum value when the calcination temperature was 700°C before declined.And the specific surface area increased with increasing the calcination temperature and reached a maximum value when the calcination temperature was 400°C before declined.The main reason is the increasing amount of mesopore with 3 nm.?3?The ultrasonic time can influence the doping amount of Ba but the specific surface area less.The doping amount of Ba decreased with increasing the ultrasonic time and reached a maximum value when the ultrasonic time was 50 min before declined;?4?The reduction temperature can influence the doping amount of Ba.The doping amount of Ba increased with increasing the reduction temperature and reached a maximum value when the reduction temperature was 450°C before declined;?5?In the range of experiment,when the calcination temperature,ultrasonic time,and reduction temperature was 700°C,50min and 450°C,respectively,the outlet of ammonia concentration of Ru/Ba-MgO-2wt%HA3 was 17.82%under the reaction conditions of 10MPa,425°C and 10000h^-1.