Efficient reduction of NOx emissions from waste double-base propellant in co-pyrolysis with pine sawdust

Co-pyrolysis technology containing biomass offers remarkable advantages in reducing NOx emissions economically and efficiently. In this work, it was innovatively introduced to solve the problem of excessive NOx emission during the incineration of waste energetic materials (EMs). The kinetics and NOx emission characteristics of waste double-base propellant (DP), pine sawdust (PS), and their mixtures with different ratios during pyrolysis were investigated by thermo-gravimetric analysis and fixed-bed experiments. The results showed that there was a significant interaction between DP and PS. Kinetic analysis by Friedman and Kissinger-Akahira-Sunose (KAS) methods demonstrated that the average activation energies of the mixtures with different ratios were smaller than that of DP, indicating that the addition of PS improved the reactivity of co-pyrolysis. In addition, the fixed-bed experiment determined that the lowest NOx emission was achieved during DP pyrolysis alone at 900 celcius. Co-pyrolysis at this temperature was found to have synergistic effects of reduced NOx emissions for different ratios of mixtures. The best synergistic effect was achieved at the mixing ratio of 60 wt% DP and 40 wt% PS, resulting in a 72.11 % reduc-tion in actual NOx emissions compared to the expected value. This study provides a new direction and powerful data support for the clean, efficient and economic treatment of waste EMs, especially for practical engineering strategies. (c) 2023 The Author(s). Published by Elsevier B.V. on behalf of King Saud University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

The co-pyrolysis technology that combines biomass can effectively and economically reduce NOx emissions. This study introduced co-pyrolysis to address excessive NOx emission during the incineration of waste energetic materials (EMs). Thermo-gravimetric analysis and fixed-bed experiments were conducted to investigate the kinetics and NOx emission characteristics of waste double-base propellant (DP), pine sawdust (PS), and their mixtures. The results showed a significant interaction between DP and PS, with the addition of PS improving the reactivity of co-pyrolysis. The lowest NOx emission was achieved during DP pyrolysis alone at 900°C, and co-pyrolysis at this temperature showed synergistic effects in reducing NOx emissions for different mixture ratios, with the best effect observed at a mixing ratio of 60 wt% DP and 40 wt% PS, resulting in a 72.11% reduction in actual NOx emissions compared to the expected value. This study provides valuable insights and data support for the clean, efficient, and cost-effective treatment of waste EMs, particularly for practical engineering strategies.