(2027) Fuel_Hydrogen-rich producer gas from air- and steam-blown co-gasification of waste polypropylene pyrolysis oil and cashew nut shell in a two-stage downdraft gasifier

Yoon J.-H.; Kim J.-S.; Kwon E.E.; Jeong S.-H.

(Elsevier Ltd) Fuel ISSN: 162361 Vol.427 Issue. Article No.139763 DOI: 10.1016/j.fuel.2026.139763

The co-gasification of waste polypropylene pyrolysis oil (WPPO) and cashew nut shell (CNS) was investigated in a two-stage downdraft gasifier to produce hydrogen-rich, low-tar gas. Experiments were conducted under air (ER = 0.3) and steam (S/C = 2.5) conditions, with selected runs incorporating activated carbon (AC) in the secondary reactor. Steam gasification achieved a maximum hydrogen concentration of 77.9 vol%. The WPPO/CNS mixing ratio affected performance, with the 1:1 blend increasing CGE from 70.3 to 89.7% to 108.9% and CCE from 68.2 to 71.5% to 83.9%, along with enhanced gas yield. The use of AC reduced gas-phase tar, and a downstream dried AC impinger further decreased tar concentration to 0.45 mg/Nm³. In contrast, the composition of condensed tar showed a shift toward heavier species during steam gasification. GC–MS analysis at a WPPO/CNS ratio of 1:1 indicated that steam gasification promoted the formation of heavier PAHs due to enhanced thermal cracking and subsequent polymerization of aromatic intermediates. Copyright © 2026. Published by Elsevier Ltd.

This work was supported by the Ministry of Economy and Finance (MOEF), Republic of Korea, and by an internal research project of the Korea Institute of Industrial Technology (KITECH) (JK260001).