Design and performance study on a novel solar moving-bed pyrolysis reactor for waste salt treatment

Industrial waste salts with organic impurities require eco-friendly treatment. Conventional pyrolysis relies on fossil fuels, however, concentrated solar energy offers a clean alternative. This study proposes a novel solar moving-bed pyrolysis reactor for purifying waste salt that combines a planar mirror with a parabolic trough concentrator to enable continuous solar irradiation of a vertical moving-bed reactor. The reactor effectively pyrolyzes organic impurities, achieving a final residual ratio below 0.02, while reactor rotation reduces the circumferential temperature difference to 50 K. Seasonal analysis determined optimal flow rates, resulting in a daily processing capacity of 82.66 kg/d in summer 96 % higher than in winter (42.17 kg/d). Furthermore, A 200 K increase in inlet temperature raised daily capacity by 39.06 %; accordingly, an integrated waste heat recovery system was designed and optimized, further enhancing the daily capacity by up to 40.63 %. This work demonstrates the viability of solar-driven pyrolysis for waste salt purification and highlights the importance of operational optimization for industrial solar thermal applications.