Potential of tri-reforming process and membrane technology for improving ammonia production and CO2 reduction

Abstract

In this work, a tri-reforming process was coupled with a membrane separation unit to enhance efficiency of ammonia (NH3) synthesis process in terms of CO2 emission, NH3 production, and NOx emission. Primary and secondary reformers were replaced by a tri-reforming process, while a Perovskite membrane was applied to separate nitrogen (N2) from oxygen (O2). A conventional NH3 synthesis process and the proposed process were simulated by Aspen-Hysys and compared in order to investigate the performance of the proposed sterategy. The simulation results indicated that when temperature increased and pressure decreased, conversion of hydrocarbons and H2/CO ratio were improved from 1.73 to 2.54, which resulted in an increase in NH3 production by 27 %, and a decrease in CO2 emission rate from 1192 kg/h to approximately 1 kg/h. The proposed sterategy was optimized in terms of different parameters e.g., temperature and pressure. Optimum reaction pressure and temperature were determined to be between 1 and 10 bar and 500–800 °C, respectively. The results of the study revealed that the proposed strategy not only removed amine and methanol sweeteners which reduce the operational costs of the process, but also decreased the NOx content from 8220 ppm to almost 10 ppm.