(2018) Journal of Cleaner Production_CO₂-looping in pyrolysis of horse manure using CaCO₃ 

Jeong K.-H., Choi D.-H., Lee D.-J., Kim J.K., Kim H., Ok Y.S., Kwon E.E.

(Elsevier Ltd) Journal of Cleaner Production ISSN: 9596526 Vol.174 Issue. Article No. DOI: 10.1016/j.jclepro.2017.11.022

This study laid a great emphasis on the mechanistic understanding of CO₂ in pyrolysis of horse manure to establish a virtuous cycle for carbon in the thermo-chemical process. To this end, CaCO₃ was used as a possible candidate for the CO₂ resource to impart synergistic environmental benefits. This study also proved the genuine roles of CO₂ in pyrolysis of horse manure. CO₂ could be a driving force to shift carbon distribution from pyrolytic oil to pyrolytic gas (i.e., the enhanced generation of CO), which provides a new means for modifying the composition of syngas as well as pyrolytic oil. Shifting carbon distribution from pyrolytic oil to pyrolytic gas could be explained through two genuine roles of CO₂ in pyrolysis of horse manure. For instance, CO₂ led to the enhanced thermal cracking of volatile matters evolved from the thermal degradation and the direct reaction between CO₂ and volatile matters to form CO, which lead to the enhanced generation of syngas and the reduction of tar formation. These identified genuine roles of CO₂ were initiated temperatures higher than 500 °C, when temperature could be decreased down to 450 °C in the presence of CaCO₃ due to the catalytic effects arising from CaCO₃. Thus, all experimental findings will be directly applicable to gasification since pyrolysis is an intermediate step in the gasification process. Moreover, the high content of CaO in biochar can be reused in the diverse environmental applications. However, the optimal conditions, especially for optimal CaCO₃ loading, should be established through further study on the subject. © 2017 Elsevier Ltd

This work was supported by “ Cooperative Research Program for Agricultural Science & Technology Development (Project No. PJ0109482017 ) funded by Rural Development Administration (RDA) in Korea.