Analysis of Biochar from Different Kinds of Feedstock and Varying Pyrolysis Temperature I: Chemical and Microscopic Properties
- Publication Type
- Journal contribution (peer reviewed)
- Authors
- Schweikle, J; spreer, W; Sringarm, K; Karaj, S; Satasup, C; Müller, J
- Year of publication
- 2016
- Published in
- Journal of Agriculture
- Band/Volume
- 32/4
- ISBN / ISSN / eISSN
- 0857_0841
- Page (from - to)
- 43-53
- Keywords
- corn, Kaffee / coffee
Biochar is an ancient method for improving soil fertility, presumably originating from South America, which has recently been rediscovered. Meanwhile the benefits of biochar are well documented. In the northern part of Thailand the management of harvesting residues is a challenge and uncontrolled burning is common place. The use of biochar may offer an alternative for land and forest management. The present study compares the quality of biochar produced with different pyrolysis temperatures. The feedstock materials were residue materials from agriculture and forestry, namely coffee shells, corn cobs and bamboo. Samples of each material were pyrolyzed in an evenly arranged pyrolysis box inside an experimental kiln for one hour at a temperature of 300, 400, 500, or 600 °C respectively. The temperature deviation was kept at <5% and three repetitions were made per test. The analyzed quality parameters of the biochar were pH, electrical conductivity (EC), organic matter content, nutrient availability and ash content. Electron microscope scan were taken at an amplification of 500 times, The weight loss, determined by weighing before and after the pyrolysis, resulted in a logarithmical curve that showed that the higher the temperature the lower the weight of the resulting biochar. The pH and EC value also increased with temperature, as well as other parameters depending on the feedstock. Organic matter content decreased accordingly and nitrogen availability proved to be constantly low, regardless of temperature or feedstock. All parameters except nitrogen depend on what temperature and material were used. While coffee shells turned out to render a biochar of rather low quality, it was shown that pyrolysis temperatures above 500°C applied to corn cobs and bamboo have the potential to produces a biochar with good chemical and structural characteristics.