Performance of a Small-Scale Haber Process

This work identifies a benchmark for the performance of a small-scale ammonia synthesis plant powered by wind energy. The energy used is stranded, far from urban centers but near locations of fertilizer demand. The wind energy drives the pressure swing absorption of air to make nitrogen and the electrolysis of water to make hydrogen. These are combined in the small-scale continuous Haber process to synthesize ammonia. The analysis of runs of the small plant presented in this article permits an assessment of how the current production rate is controlled by three resistances: catalytic reaction, ammonia separation by condensation, and recycling of unreacted gas. The measured catalytic reaction rates are consistent with separate experiments on chemical kinetics and with published reaction mechanisms The condensation rates predicted are comparable with literature correlations. These rate constants now supply a rigorous strategy for optimizing this scaled-down, distributed ammonia plant. Moreover, this method of analysis is recommended for future small-scale, distributed manufacturing plants.