Paper details

Title:

Air-CO2 Gasification of Biomass Pellets in a Pilot-scale Downdraft Gasifier

Author(s):

Pellegrini Susini, G.A., Kallis, K.X., Petrolati, A., Oakey, J.E.

Document(s):

Abstract:

Biomass has the highest potential to contribute to a sustainable energy supply. Gasification is a process that converts carbonaceous materials, such as coal or biomass, into a rich gas in carbon monoxide and hydrogen by reacting the raw material at high temperatures with a controlled amount of oxygen and/or steam. The use of air as gasifying agent typically leads to a reduction of the CV of the syngas due to the dilution with nitrogen. The authors carried out a series of test in a pilot­scale downdraft gasifier to identify the feasibility of CO2 gasification, partially replacing air with CO2 as a gasifying agent, using Miscanthus pellets to perform the experiments. The results showed that, between 650oC and 750oC, the presence of CO2 did not lead to a more efficient conversion of the carbon in the fuel. In fact, the injection of CO2 did not promote the CO formation in the gas, due to the initial high amount of CO2 that was injected. This led to a decrease in the temperature of the process and to a low gasification rate for all the gasification reactions and for the char. Moreover, the char was not properly activated by the CO2 and its high concentration also inhibited the CO formation. Furthermore, the high CO2 concentration played a higher role than the catalytic effect of the alkali metals on the surface of the solid (char), leading to a reduction of the gasification rate.

Keywords:

biomass, carbon dioxide (CO2), gasification, pilot plant, pellets

Topic:

Biomass Conversion Technologies for Heating, Electricity and Chemicals                  

Subtopic:

Gasification for synthesis gas production

Event:

19th European Biomass Conference and Exhibition

Session:

VP2.4.16

Pages:

1589 - 1593

ISBN-13:

978-88-89407-55-4

ISBN-10:

88-89407-55-7

Paper DOI:

10.5071/19thEUBCE2011-VP2.4.16

Price:

FREE