Authors: Gianluigi Farru, J?rgen Kern, Judy Libra, Huyen Chau Dang, Sibylle Uhlemann, Marcus Fischer, Giovanna Cappai
Published in: CSBE-SCGAB Technical Conferences » 5th CIGR and AGM Quebec City 2021 » Special Session on Biochar
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Description: Currently, interest in char substrates as a component in growing media is increasing. They may be an important option to replace peat, which is a valuable carbon sink on Earth. Thermochemical conversion of biomass to chars can run at high temperatures (400-600?C) by pyrolysis and at low temperatures (200-250?C) by hydrothermal carbonization (HTC). Some knowledge already exists on the suitability of pyrolytic biochars as a substitute for peat in growing media, but little is known about chars derived from HTC. Based on their acidic pH values and an electrical conductivity similar to peat, they are promising candidates. However, due to the conditions of the HTC process, the char products often contain toxic phenolic compounds. This raises the question, if a post-treatment can be used to remove undesirable compounds in the fresh HTC chars. In this study, both the production of char as well as post-treatment were investigated. The effect of process conditions on the production of phenolic compounds was determined for various feedstocks (digestate from cow manure, spent coffee ground). In addition, different post-treatments of HTC chars (degassing at 20?C, thermal treatment at 105?C and washing with water), separately and/or in combination, have been tested for their ability to reduce the contents of phenols and furfurals. Germination tests with post-treated HTC chars were applied to indicate the effect of phytotoxic compounds. The work will discuss how the operating conditions during thermochemical conversion and the applied post-treatments influence the final quality of amendments with tailor-made properties.
Conference name: 5th CIGR International Conference and CSBE-SCGAB AGM 2021, Quebec City,QC, 11-14 May 2021.
Session name: SPECIAL SESSION Biochar 2
Publication type: Presentation
Language 1: en
Rights: Canadian Society for Bioengineering