Charcoal from anaerobically digested dairy fiber for removal of hydrogen sulfide within biogas

Abstract

Anaerobically digested fibrous solid (AD fiber) is an abundant material that offers potential to produce value-added products such as biochar. The objective of this paper is to better understand how thermochemical processing conditions affect the capacity of biochars derived from AD fiber to adsorb H 2 S from biogas. AD fiber was pyrolyzed in an electric tube reactor at temperatures up to 600° C and 60 min. The chars were employed for H 2 S scrubbing tests from a synthetic biogas. Results showed that the chars' capacity for H 2 S removal is comparable to that of activated carbon. An additional step consisting of impregnation of the chars with Na 2 CO 3 resulted in an improved capacity for H 2 S removal. To study the effect of ash, the AD fiber was also subjected to an alternative thermal treatment, hot water extraction (HWE), at 200° C for 60 min. The resulting HWE material …