Abstract:

Hydrogen energy is one of the most promising clean energy sources. Green hydrogen production can be achieved by electrolyzing water from renewable energy sources, but the efficient storage and transportation conditions of hydrogen are difficult. Ammonia is an efficient hydrogen storage material, but the high temperature and high pressure reaction conditions required for ammonia synthesis lead to high energy consumption. Therefore, the process development of hydrogen production from renewable energy electrolytic water - low temperature and low pressure ammonia synthesis is of great significance for green transformation of energy and low-carbon development of company. Based on Aspen Plus process simulation software, this study designed and developed a process of hydrogen production from renewable energy electrolytic water - low temperature and low pressure ammonia synthesis. Combined with the production conditions of synthetic ammonia industrial demonstration enterprise, a 10000 t synthetic ammonia demonstration production process was reasonably designed. The photovoltaic power generation combined with network electricity was used to supply energy for the alkaline electrolytic water to produce hydrogen, and 1000 m³/h (standard condition) hydrogen with the purity of 99.999% was produced at 85℃ and 1.6 MPa. In order to meet the demand for 10000 t synthetic ammonia, further combined with the existing nitrogen and hydrogen-nitrogen mixture of the industrial demonstration enterprises, the reaction of ammonia synthesis was carried out at 400℃ and 7 MPa, and the liquid ammonia product with a purity of 99.9% was obtained by ammonia cold separation. In addition, the high energy consumption synthetic ammonia process is designed with four heat exchangers to save energy. This study can provide a reference for the industrial demonstration of low temperature and low pressure ammonia synthesis with hydrogen production from renewable energy electrolytic water.

Key words: renewable energy, water electrolysis, hydrogen production, ammonia synthesis, optimal design

摘要：

氢能是目前最具前景的清洁能源之一，通过可再生能源电解水制氢可以实现绿氢生产，但氢气的高效储存和运输难度较大。氨是高效的储氢材料，但合成氨所需高温高压的反应条件致使过程能耗较高，因此发展可再生能源电解水制氢-低温低压合成氨工艺对于能源绿色转型和企业低碳发展具有重要意义。基于Aspen Plus流程模拟软件，设计开发了可再生能源电解水制氢-低温低压合成氨工艺流程，并结合合成氨工业示范企业的生产条件，合理设计万吨级合成氨示范生产工艺。采用光伏发电联合电网为碱性电解水制氢装置供电，在85℃、1.6 MPa下生产1000 m³/h（标准工况）纯度为99.999%的氢气。为了满足万吨级合成氨需求，进一步结合示范企业现有氮气和氢氮混合气共同进料，在400℃、7 MPa下反应生成氨，经氨冷分离得到纯度为99.9%的液氨产品。此外，对耗能较高的合成氨工艺进行四次换热设计，节省能耗。本研究为可再生能源电解水制氢-低温低压合成氨的工业示范提供参考。

关键词: 再生能源, 电解水, 制氢, 合成氨, 优化设计