Pyrolysis temperature and heating time affect rice hull biochar properties
Rice hulls are an abundant byproduct of rice production, and thus potentially useful as a feedstock in pyrolysis systems that generate biofuels and biochar. Pyrolysis temperatures affect the relative mass of biofuel and biochar, as well as their properties. The objective of this research was to determine the effect of pyrolysis temperature and exposure duration (time) on rice hull biochar properties, and subsequently, their effect on nursery and greenhouse substrates. Parboiled rice hulls were subjected to temperatures of 200, 400, or 600°C for 1, 2, or 4 h. Mass of rice hulls were reduced 12, 57, and 63% at temperatures of 200, 400, and 600°C, respectively. Elemental composition generally increased proportionally to the decrease in mass, as carbon, hydrogen, and oxygen were burned off and other macro- and micro-nutrients were concentrated in the resultant biochar (with the exception of sulfur). Phosphate and potassium release increased with temperature and time, and was greatest from biochar heated to 600°C. Calcium, magnesium, and micronutrient concentrations were low regardless of pyrolysis treatment.
Altland, J., Locke, J. and Boldt, J. (2018). Pyrolysis temperature and heating time affect rice hull biochar properties. Acta Hortic. 1191, 145-152
container production, greenhouse, nursery, nutrients, phosphorus, plant nutrition, potassium, potting mix, substrate