Particle-scale modeling of oxygen uptake rate during pig manure-wheat straw composting: A new approach that considers surface convection

摘要

A new oxygen uptake rate (OUR) model that considers surface convection between composting materials and gas (Q_(surf)) has been developed for the composting of pig manure and wheat straw. This was found to provide a more precise simulation of maximum OUR, which was especially true for the thermophilic phase due to a significant increase in the temperature difference between the composting materials and gas in the bottom part of reactor. Heat contribution analyses indicated that Q_(surf) heat loss represents 8.86% of the total, implying that Q_(surf) needs only be quantified for large-scale composting systems, and so can be omitted with systems in which there is a small exchange-surface of composting materials. Sensitivity analyses suggested that expanding the exchange-surface could protect microorganisms from overheating and be beneficial to degradation. These findings provide a theoretical basis for improving simulation precision, while also further elucidating the heat transfer mechanism during composting.