Charcoal from anaerobically digested dairy fiber for removal of hydrogen sulfide within biogas. (June 2018)

• Record Type: Journal Article
• Authors: Pelaez-Samaniego, Manuel Raul; Smith, Matt W.; Zhao, Quanbao; Garcia-Perez, Tsai; Frear, Craig; Garcia-Perez, Manuel
• Is Part Of: Waste management. Volume 76(2018)
• Page Start: 374
• Page End: 382
• Publication Date: 2018-06
• Subjects: Dairy manure fiber -- Anaerobic fiber -- Carbonization -- Charcoal -- Biogas cleaning; Hazardous wastes -- Periodicals; Refuse and refuse disposal -- Periodicals; 363.728
• DOI: 10.1016/j.wasman.2018.03.011
• Languages: English
• ISSNs: 0956-053X

Abstract

Graphical abstract: Highlights: Anaerobically digested (AD) fiber was used for charcoal production via pyrolysis. Charcoal from AD fiber can effectively adsorb H2 S from biogas. Impregnation of charcoal from AD fiber with Na2 CO3 increases H2 S sorption capacity. Ash in the AD fiber helps the retention of S on the surfaces of the char. Charcoal manufacture is a promising approach to use abundant AD fiber. 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 H2 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 H2 S scrubbing tests from a synthetic biogas. Results showed that the chars' capacity for H2 S removal is comparable to that of activated carbon. An additional step consisting of impregnation of the chars with Na2 CO3 resulted in an improved capacity for H2 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 showed no removal of H2 S from biogas, indicating that the ash and the environment employed for the thermal treatment of AD fiber play an important role in the char's performance for H2 S removal. Results also suggest that a portion of the S in the charcoal after the H2 S sorption process exists as free or adsorbed S (i.e., not chemically bonded to the charcoal).