Degradation kinetics of biochar from pyrolysis and hydrothermal carbonization in temperate soils (Plant and Soil ,Vol. 372, No. 1/2, November 2013 )

Abstract :Background and Aims Estimates of biochar residence times in soils range over three orders of magnitude. We present the first direct comparison between the biodegradation of a char from hydrothermal carbonization (htcBC) and pyrolysis (pyrBC) with high temporal resolution. Methods Mineralization of the biochars and their shared Miscanthus feedstock in three soils was determined directly by the ¹³CO₂ efflux using a novel method incorporating wavelength scanned cavity ring-down spectroscopy. Biochar half-life (t ½ ) was estimated with three empirical models. Results (1) The htcBC was readily biodegradable, whereas pyrBC was more recalcitrant. (2) Cumulative degradation of both biochars increased with soil organic carbon and nitrogen content. (3) The corrected Akaike information criterion (AIC C ) showed an overall preference for the double exponential model (DEM) reflecting a labile and a recalcitrant C-pool, over the first-order degradation model (FODM) and a logarithmic model. (4) The DEM resulted in t ½ ranging from 19.7-44.5, 0.7-2.1 and 0.8-1.3 years for pyrBC, pyrBC and feedstock, respectively. Conclusion The degradation was rather similar between feedstock and htcBC but one order of magnitude slower for pyrBC. The AIC C preferred FODM in two cases, where the DEM parameters indicated no distinction between a labile and recalcitrant carbon pool.

Combustion Kinetics of Biochar Prepared by Pyrolysis of Macadamia Shells..PDF enclosed

Kinetics investigation on the combustion of biochar in O 2 /CO 2 atmosphere: Sustainable Energy Section...PDF enclosed

Characterization of corncob-derived biochar and pyrolysis kinetics in comparison with corn stalk and sawdust...PDF enclosed

There is very nice software is called GraphPad prism, you can use it for any kinetic study, this software generate a proper fit  (rate equation) for your experimental data, also you will get K, life time of reaction (taw), and t1/2. Give it a go!