Life cycle energy and greenhouse gas profile of a process for the production of ammonium sulfate from nitrogen-fixing photosynthetic cyanobacteria.
In this paper, an alternative means for nitrogen fixation that may consume less energy and release less greenhouse gases than the Haber-Bosch process is explored. A life-cycle assessment was conducted on a process to: culture the cyanobacterium, Anabaena sp. ATCC 33047, in open ponds; harvest the biomass and exopolysaccharides and convert these to biogas; strip and convert the ammonia from the biogas residue to ammonium sulfate; dry the ammonium sulfate solution to ammonium sulfate crystals and transport the finished product. The results suggest that substantial reductions in non-renewable energy use and greenhouse gas emissions may be realized. The study opens the possibility that Haber-Bosch ammonia may be replaced with ammonia from a biomass process which simultaneously generates renewable energy. The process is intrinsically safer than the Haber-Bosch process. However, there are trade-offs in terms of land use and possibly, water.
Department of Chemical Engineering, De La Salle University, 2401 Taft Avenue, 1004 Manila, Philippines. luis.razon@dlsu.edu.ph
Luis F
LF
Razon
D000645:Ammonium Sulfate / Q000378:metabolism*; D018533:Biomass; D000458:Cyanobacteria / Q000378:metabolism* / Q000502:physiology; D005740:Gases; D017752:Greenhouse Effect; D009586:Nitrogen Fixation; D010788:Photosynthesis
D005740:Gases; D000645:Ammonium Sulfate