Modeling and Optimal Design of Absorbent Enhanced Ammonia Synthesis

Synthetic ammonia produced from fossil fuels is essential for agriculture. However, the emissions-intensive nature of the Haber–Bosch process, as well as a depleting supply of these fossil fuels have motivated the production of ammonia using renewable sources of energy. Small-scale, distributed proc...

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Bibliographic Details
Published in:Processes 2018-07, Vol.6 (7), p.91
Main Authors: Palys, Matthew, McCormick, Alon, Cussler, E., Daoutidis, Prodromos
Format: Article
Language:English
Subjects:
10 SYNTHETIC FUELS
Agricultural economics
Alternative energy sources
Ammonia
ammonia synthesis
Capital costs
Carbon
Chemical engineering
Condensates
Design optimization
dynamic modeling
Dynamic models
Economics
Economies of scale
Effluents
ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
Fertilizers
Fossil fuels
Haber Bosch process
Heat exchangers
Hydrogen
NANOSCIENCE AND NANOTECHNOLOGY
Nitrogen
Renewable resources
Stainless steel
Temperature
WIND ENERGY
Wind power
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Summary:Synthetic ammonia produced from fossil fuels is essential for agriculture. However, the emissions-intensive nature of the Haber–Bosch process, as well as a depleting supply of these fossil fuels have motivated the production of ammonia using renewable sources of energy. Small-scale, distributed processes may better enable the use of renewables, but also result in a loss of economies of scale, so the high capital cost of the Haber–Bosch process may inhibit this paradigm shift. A process that operates at lower pressure and uses absorption rather than condensation to remove ammonia from unreacted nitrogen and hydrogen has been proposed as an alternative. In this work, a dynamic model of this absorbent-enhanced process is proposed and implemented in gPROMS ModelBuilder. This dynamic model is used to determine optimal designs of this process that minimize the 20-year net present cost at small scales of 100 kg/h to 10,000 kg/h when powered by wind energy. The capital cost of this process scales with a 0.77 capacity exponent, and at production scales below 6075 kg/h, it is less expensive than the conventional Haber–Bosch process.
ISSN:2227-9717
2227-9717
DOI:10.3390/pr6070091