Preliminary Study On Polygeneration Systems For Production Of Ammonia And Power

By means of process coupling and system integration, polygeneration systems for production of ammonia and power can achieve good distribution for material and energy in chemical subsystem and power generation subsystem, and present more opportunities to achieve higher energy utilization efficiency and less environmental impact compared to single production systems, which has a promising prospect. Sponsored by the National Key Project (2005CB221207) and the NSF of China (90210032), this study focuses on polygeneration systems for production of ammonia and power. Basing on the basic principle for integration of polygeneration system, the aim of this study is to explore different configurations for ammonia-power polygeneration systems, to propose novel polygeneration systems for production of ammonia and power, and to reveal the specific features of polygeneration systems. The main contents are as follows:The integration features of coal-based and natural gas based polygeneration systems for production of ammonia and power are investigated. Through the comparison between methanol synthesis process and ammonia synthesis process, the specific features of chemical production process with different product and their effects on integration of the polygeneration system are discussed.On the basis of simulations for single production systems and polygeneration system, coal-based polygeneration system for production of ammonia and power is investigated. By means of exergy analysis, the energy utilization of coal-based ammonia synthesis system is studied, the potential for system improvement is pointed out and the integration measures are recommended. Using the energy utilization diagram methodology, the internal phenomenon of the key processes in polygeneration system isrevealed.A novel natural gas based polygeneration system for production of ammonia and power in sequential configuration, especially adopting partial reforming and partial recycle ammonia synthesis scheme, is proposed. The characteristic of system performance with key parameters such as steam to carbon, reforming temperature and cycle ratio is discussed. Through integrating partial reforming and partial synthesis, this new system reaches the coupling between ammonia synthesis process and power generation system, receives good results on energy saving and shows significant role of combined cascade utilization of chemical and physical energy in polygeneration system integration.