Study on the reaction mechanism of nitrogen-containing gases from polyurethane pyrolysis with carbonate molten salts
Year: 2025
Type: article
Abstract: Polyurethane (PU) is extensively utilized in industrial and consumer applications. However, the direct pyrolysis of PU will generate nitrogen-containing tail gases such as NO and NO 2 . In this study, alkaline carbonate molten salts are innovatively used to neutralize the nitrogen-containing gases produced during the pyrolysis of PU while pyrolyzing it. The results of TG tests show that the thermal decomposition of PU can be divided into two processes: functional group cracking (502.97–640.30 K) and carbonization (640.30–765.44 K), with activation energies of 161.48 kJ mol −1 and 419.72 kJ mol −1 respectively. The carbonization process generates reactive carbon intermediates, which then participate in the reduction of NO 2 to yield NO and CO. The presence of carbonates can effectively absorb NO 2 and NO tail gases and generate nitrates and nitrites in the molten salts. The existence of nitrates also enables the generation of O 2 2− , an oxidizing ion, in the molten salts, which promotes the further decomposition of residues. EM-EDS and XRD analyses confirm molten carbonate salts effectively intercept nitrogenous gases, with HSC simulations validating this capture mechanism. Therefore, carbonate molten salts can adsorb nitrogen-containing tail gases while catalyzing the further oxidation of residues. Molten salt oxidation is an advanced means suitable for the safe and green treatment of PU.
Source: Fuel
Authors: Yang-Hai Zheng, Jun-Qiang Rui, Sheng-Rong Guo, Cheng Yao, Zhao-Yang Liu, Yun Xue, Ju-Yue Yang, Yong-De Yan
Language: English
Topic: Thermal and Kinetic Analysis
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,330
OpenAlex ID: W4409852593