不同净化工艺下氧气纯度对合成氨流程能耗的影响

For synthetic ammonia processes using pure oxygen, the energy consumption of air separation unit is huge that has great potential for energy saving. If the oxygen purity can be properly reduced, the energy consumption of the whole ammonia process can be reduced effectively. Meanwhile, the operation cost of the subsequent purification unit increases due to the increase of flow rate. Therefore, there is an optimal oxygen purity which makes the whole process energy efficiency. Aspen Plus was used to simulate the whole industrial ammonia synthesis process with methanation refining, and the results were compared with the liquid nitrogen purification process. Effects of oxygen purity from air separation were considered. The results show that the purity of oxygen has certain effects on energy consumption of purification, and the profiles of energy consumption against oxygen purity obtained by the two processes are very similar. After comparative analysis of energy consumption and operational cost, the liquid nitrogen washing process with 92% oxygen purity is found as the optimal solution for ammonia synthesis. This result is useful for practical production.