Release of Chlorine and Sulfur during Biomass Torrefaction and Pyrolysis

A1 Journal article (refereed)

Internal Authors/Editors

Publication Details

List of Authors: Suriyati Binti Saleh, Julie Pauline Flensborg, Tooran Khazraie Shoulaifar, Zsuzsa Sárossy, Brian Brun Hansen, Helge Egsgaard, Nikolai DeMartini, Peter Arendt Jensen, Peter Glarborg, Kim Dam-Johansen
Publication year: 2014
Journal: Energy and Fuels
Volume number: 28
Issue number: 6
Start page: 3738
End page: 3746
eISSN: 1520-5029


The release of chlorine (Cl) and sulfur (S) during biomass torrefaction and pyrolysis has been investigated via experiments in two laboratory-scale reactors: a rotating reactor and a fixed bed reactor. Six biomasses with different chemical compositions covering a wide range of ash content and ash-forming elements were torrefied/pyrolyzed in the temperature range of 150–500 °C. The relative release of chlorine and sulfur was calculated based on mass balance and analysis of the biomass before and after torrefaction. In selected cases, measurement of methyl chloride (CH3Cl) in the gas from straw torrefaction has furthermore been conducted. The release of chlorine from straw was first observed at 250 °C and peaked with about 60–70% at 350 °C. Analysis of the released gas showed that most of the chlorine was released as methyl chloride. Increasing the straw content in the reactor resulted in a lower fractional release of Cl, probably due to more reactive sites in contact with gas phase Cl species leading to secondary binding of Cl to the solid product. Almost complete release of chlorine was observed for woody biomass at 350 °C. This result is in agreement with previous studies reporting that biomasses with a lower chlorine content release a higher fraction of chlorine during the pyrolysis process. A significant sulfur release (about 60%) was observed from the six biomasses investigated at 350 °C. The initial sulfur content in the biomass did not influence the fraction of sulfur release during torrefaction.

Last updated on 2019-16-10 at 03:03