Issue 20, 2022

Thermokinetics of production of biochar from crop residues: an overview

Abstract

The total annual production of agricultural biomass such as wood, corn cobs, leaves, and citrus peels, is estimated at 956 million tons (Mt). Since crop residues are by-products of agricultural production, crop residue collection does not compete with food crops for acreage and therefore, it does not negatively impact food prices. Moreover, it has the advantage of reducing the amount of waste, the disposal of which often becomes a serious problem despite natural sources. Biomass conversion becomes a very valid alternative to diversify energy sources and reduce global warming. Thermochemical treatment of biomass is a promising way to convert biomass into bio-oil, biochar, and gas. In recent years, interest in the conversion of plant biomass into biochar has increased because this carbonaceous material has interesting properties that guarantee applications in wastewater treatment, soil improvement, solid fuels, and energy. The processes performed to convert biomass into biochar are different and the most used are thermochemical processes: pyrolysis, torrefaction, hydrothermal treatment, and gasification. The studies of the thermokinetic parameters that control these processes are carried out using different methods that provide the necessary information for the applicability of the processes on an industrial scale. One of the objectives of the present review is to compare kinetic models in order to clarify the role of the conversion process and the effects of the process parameters on the final product. A comprehensive investigation of the thermokinetic parameters controlling the conversion of crop residues to biochar was conducted. The mathematical description of kinetic processes is usually performed using the Arrhenius equation and its derivatives to obtain the activation energies (Ea), the pre-exponential parameter, and the process mechanisms. While isothermal processes can be described using the model fitting method, isoconversional processes can be studied using both the model fitting method and model-free methods. The high complexity and diversity of the reactions involved could lead to the use of approximations. In this paper, an overview of the kinetic parameters determined for biochar production processes and the model used to determine them is given.

Graphical abstract: Thermokinetics of production of biochar from crop residues: an overview

Article information

Article type
Tutorial Review
Submitted
15 জুলাই 2022
Accepted
15 চেপ্টে 2022
First published
27 চেপ্টে 2022

Green Chem., 2022,24, 7801-7817

Thermokinetics of production of biochar from crop residues: an overview

T. Len, V. Bressi, A. M. Balu, T. Kulik, O. Korchuganova, B. Palianytsia, C. Espro and R. Luque, Green Chem., 2022, 24, 7801 DOI: 10.1039/D2GC02631G

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements