posted on 2019-05-09, 00:00authored byAntonio Sánchez, Mariano Martín, Pastora Vega
The synthesis of
ammonia is one of the most important chemical
processes in the world. The Haber–Bosch process has predominantly
been used to synthesize ammonia over the last decades. However, it
uses coal or natural gas as raw materials. In this work, the path
to produce ammonia from biomass has been evaluated and optimized.
Thermochemical and biochemical routes have been compared. Three alternative
gasification technologies have been considered together with anaerobic
digestion. For the reforming stage, two alternatives have been compared:
autothermal and steam reforming. Finally, ammonia is synthesized in
a multibed reactor with two different configurations: direct or indirect
cooling. The problem is formulated as a mixed integer nonlinear program
but solved as a set of 14 nonlinear programs. Indirect gasifier followed
by steam methane reforming and direct cooling ammonia reactor is the
path that presents the best performance with an ammonia production
cost of about 380 €/t. The biochemical route shows worse results
to ammonia due to the low yield to biogas and, therefore, to ammonia.