CO2 Gasification of Sugarcane Bagasse Char: Consideration of Pyrolysis Temperature, Silicon and Aluminum Contents, and Potassium Addition for Recirculation of Char

Author(s)

Motta, Ingrid Lopes ^[1] ; Arnold, Ross A. ^[1] ; Lopez-Tenllado, Francisco Javier ^[1] ; Maciel Filho, Rubens ^[2] ; Wolf Maciel, Maria Regina ^[2] ; Hill, Josephine M. ^[1]

Affiliation

^[1] Univ Calgary, Dept Chem & Petr Engn, Schulich Sch Engn, Calgary, AB T2N 1N4 - Canada

^[2] Univ Estadual Campinas, Lab Optimizat Design & Adv Control, Sch Chem Engn, BR-13083852 Campinas, SP - Brazil

• Document type: Journal article
• Source: ENERGY & FUELS; v. 34, n. 12, p. 16201-16211, DEC 17 2020.
• Web of Science Citations: 0

Abstract

In sugarcane bagasse gasification, char recirculation to the gasifier improves the syngas quality and process efficiency. To determine the effect of char properties on the reaction kinetics, in this work, the pregasification pyrolysis temperature, particle size, and catalyst (potassium) loading were varied. Char samples were prepared at 750-900 degrees C via pyrolysis and gasified isothermally in a thermogravimetric analysis unit at 850 degrees C with CO2, and gasification data were modeled using the random pore and extended random pore models. Increasing pyrolysis temperatures did not affect the char morphology and surface composition but did reduce the surface area, as determined by N-2 adsorption, decreasing initial gasification rates, and the overall fitted rate constants. Reduction of the particle size via ball milling decreased the time required for complete conversion and changed the shape of the rate versus conversion curves from monotonically decreasing to concave down. The char sample prepared via pyrolysis at 900 degrees C was an exception, having a maximum rate at similar to 10% conversion without ball milling. After ball milling of the char sample prepared at 750 degrees C, there was an accumulation of ash (Al and Si) on the surface of the particles and a reduction in the surface area, consistent with the ash blocking pores-the porosity in these samples increased during the initial stages (up to similar to 20% conversion) of gasification. The gasification behavior was generally well modeled by the extended random pore model. Although the addition of KOH (K/AI mass ratio similar to 0.2-1.25) enhanced the gasification rates, too much K-from the addition of KOH or after 90% conversion-created mass-transfer limitations resulting in lower gasification rates. (AU)

• FAPESP's process: 15/20630-4 - Biorefinery development integrated to a bioethanol sugar cane plant with zero CO2 emission: routes to convert renewable resources to bio-products and bio-electricity
• Grantee: Rubens Maciel Filho
• Support Opportunities: Research Projects - Thematic Grants