Hi all,
The pyrolysis of biomass is often studied with the help of Biot, Pyrolysis and Pyrolysis prime numbers. But, the heat transfer coefficient is calculated by empirical correlations applicable to the bulk behavior.
Does that consider the convection in the pores and between particles?
The work by the Dauenhauer Research Group suggest that the heating rates for TGA and pyroprobes are in the order of 2 and 200 Deg C/s respectively.
Considering significant differences in slow and fast pyrolysis chemistry. How accurate are the predictions made by using this data?
Apologize for the long queries.
Thank you very much in advance for helping.
Warm regards,
Adjay
The product of biomass pyrolysis can be broadly categorised into three groups which include the condensable organic product (in the liquid state), char (solid) and non-condensable gases (CO, CO2, H2, CH4). Many studies have been carried out both on experimental and numerical aspects in the biomass fast pyrolysis, but the exact reaction mechanism and the kinetics involved in the pyrolysis reaction remain uncertain. Thus, several studies have been attempted for developing the kinetic model for biomass fast pyrolysis These studies assumed that three major products including gas, char, and organic liquid (tar) are obtained from the competitive pyrolysis reaction of a single component of biomass.
Hi dear Adjay.
With regard to the heating rate for the pyrolysis process, it is necessary to take into account the shape and uniformity of the biomass, that is, if it is spherical, elliptical. In addition, the mass used in the pyrolysis process, whether continuous or batch, the residence time and contact with the components that transfer heat. In terms of heat transfer, the higher the heating rate, the lower the biomass uniformity and the higher the mass, the lower the conversion into condensable gases (bio-oil), with higher waste formations (pyrolytic coal), since the transfer heat is being hampered by these factors. In this way, all the variables mentioned above, also counting with the humidity of its biomass, must be thoroughly studied, depending on the objective that it intends to achieve with the pyrolysis. As for the accuracy of the data, it is really difficult to have an exact accuracy, since most biomasses are composed of hemicellulose, cellulose and lignin and the process itself is done with the degradation of the three components, generating several models to explain the pyrolysis of biomass. There are independent parallel reaction (IPR) models, which discuss the degradation of each component and the formation of others, giving an estimate of kinetic parameters (activation energy, among others).
An article on the IPR of the pyrolysis of sugarcane bagasse follows:
https://www.sciencedirect.com/science/article/pii/S0263876212001426
Warm regards,
Ferreira
Thank you very much for taking time to answer the queries.
Warm regards,
Adjay
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