Novel design of parabolic trough concentrator-solar reactor for pyrolysis of waste salt

Parabolic trough concentrator (PTC) can be used as heat source of solar pyrolysis reactor (SPR) to pyrolyze organic impurities in waste salt. However, the conventional PTC-SPR is prone to two significant issues, uneven energy flux distribution and excessive temperature difference (ΔT). To address those issues, this study proposes a novel SPR structure featuring two semi-circular tubes with a gap width of H. A design method for the secondary plane reflector is established and the effect of H on energy flux distribution is investigated. The optimal H of 50 mm is identified, improving energy flux uniformity by 30.36 % compared to the conventional design. Photothermal coupling and pyrolysis performance analyses confirm that H = 50 mm delivers optimal results: ΔT is reduced by 75.20 %, reaction completion time (t_end) is shortened by 7.89 %, and thermal efficiency (η_T) is enhanced by 3.68 %. Furthermore, preheating the waste salt accentuates the advantages of the novel PTC-SPR. This work provides significant insights for designing and applying PTC-SPR systems for the removal of organic impurities from industrial waste salts.