Production of Activated Carbon within the Dual Fluidized Bed Gasification Process
Artikel i vetenskaplig tidskrift, 2015

A key step in the production of clean energy from biomass gasification is the cleaning of the product gas to remove impurities, such as tars, H2S, HCl, particulates, and alkali compounds. Some gas cleaning systems employ activated carbon (AC), with Brunauer-Ernmett-Teller (BET) surface areas in the range of 800-1300 m(2)/g. Because the operational conditions for the production of AC are similar to those applied in the gasification chamber of a dual fluidized bed gasifier, the possibility to produce AC within the dual fluidized bed gasification (DFBG) process was investigated in the present work. Wood pellets were gasified with steam in a fluidized bed reactor at 800 and 840 degrees C. Part of the unconverted char from this process was further activated with steam in a fixed bed reactor at 850 degrees C. The results obtained indicate that if >= 44% of the char that results from the devolatilization of the wood pellets is gasified (the extent of char conversion), the unconverted char acquires a BET surface area >900 m(2)/g, which makes it suitable for use in gas cleaning processes. Achieving this extent of char conversion in the gasification chamber of industrial dual fluidized gasification plants would remove the need and cost for a second reactor for further activation of the unconverted char. The cost of the produced activated carbon (AC) has been estimated as being 15-fold lower than that of commercially available AC. This suggests that the production of AC as part of the dual fluidized bed gasification process would be cost-effective.

Removal

Steam

Gasifier

Temperature

Biomass Gasification

Agricultural

Physical Activation

Residues

Tar

Hydrogen-Sulfide

Hot-Gas

Författare

Placid Tchoffor Atongka

Chalmers, Energi och miljö, Energiteknik

K. O. Davidsson

SP Sveriges Tekniska Forskningsinstitut

Henrik Thunman

Chalmers, Energi och miljö, Energiteknik

Industrial & Engineering Chemistry Research

0888-5885 (ISSN) 1520-5045 (eISSN)

Vol. 54 3761-3766

Drivkrafter

Hållbar utveckling

Ämneskategorier

Energiteknik

Bioenergi

Styrkeområden

Energi

DOI

10.1021/ie504291c