Co-generation of hydrogen and ammonia from waste tires valorization through chemical looping approach

The burgeoning global demand for clean fuels and chemicals presents a formidable challenge, necessitating the development of innovative solutions that can harness waste streams as feedstocks. This comprehensive techno-economic analysis investigates the feasibility of simultaneously generating hydrogen and ammonia from waste tires through the integration of advanced process technologies, offering a compelling pathway to address both energy needs and waste management in a synergistic manner. Three distinct process integration cases were rigorously evaluated: Design 1 leveraged a chemical looping approach to generate the required nitrogen for conventional ammonia generation via the Haber-Bosch process while producing hydrogen from gasification of waste tires; Design 2 seamlessly integrated gasification of tires with steam methane reforming to exploit thermal synergies; and Design 3 pioneered a novel chemical looping for ammonia generation (CLAG) process, which circumvented the energy-intensive air separation and high-pressure Haber-Bosch operations. The results unequivocally demonstrate the superiority of the CLAG-based approach, with Design 3 achieving the lowest levelized cost of ammonia generation at a remarkable $0.41/kg. Design 3 also exisbited the highest cold gas efficiency of 97% and an impressive process efficiency of 63.4%, far exceeding the performance of the other configurations. In contrast, the standalone Haber-Bosch-driven Design 1 exhibited a substantially higher ammonia cost of $0.49/kg, a low cold gas efficiency of 79%, and a process efficiency of only 35%. Overall, the study demonstrates that the Chemical Looping Ammonia Generation (CLAG) configuration (Design 3) is the most efficient and economically competitive route. Design 3 reduces the levelized cost of ammonia to $0.41/kg—representing a 37–43% reduction compared to Designs 1 and 2—while achieving the highest overall process efficiency (63.4%) and cold gas efficiency (97.1%). These results establish CLAG as a superior pathway for waste-tire valorization and a viable alternative to conventional Haber–Bosch–based ammonia production.