System for Biochar Preparation and Activation

Abstract

Conversion of various types of waste biomass to biochar represents a cheap alternative to commercially available activated carbon adsorbents. A two-stage laboratory apparatus for the biochar preparation with external steam activation was designed. The Biochar preparation by the pyrolysis of biomass took place in a horizontal quartz furnace. Liquid and gaseous products were drained through a system of coolers and collected for a subsequent mass balance of the process. Analysis of the pyrolysis gas was provided via GC-TCD-FID. The activation of the obtained biochar was carried out in an externally heated steel reactor using steam under the nitrogen or carbon dioxide atmosphere. The sample base consisted of a hardwood, spruce wood and extracted coffee. Biochar, prepared by pyrolysis of the aforementioned materials up to 700 or 600 °C, was subsequently activated by steam. The specific surface, the pore size distribution and the volatile matter content of the herewith prepared adsorbents indicate their good practical usability. It was verified that the self-designed laboratory apparatus as well as proposed methods for the key parameters evaluation are suitable for fast and operative testing of conversion of the various types of the waste biomass into the activated carbon-based adsorbents.