An operation strategy towards efficient energy recovery from integrated anaerobic digestion and pyrolysis of corn stalk

Abstract

In this work, an integrated process of anaerobic digestion (AD) and pyrolysis (PY) was developed to eliminate the obstacles of single AD or PY application, such as long period, low efficiency and poor quality of products. The influence mechanism of different AD times on the energy recovery of integrated process was explored, and alkali pretreatment was performed to optimize energy recovery. Results showed that the fluctuation of indicators mainly concentrated in the initial stage of AD due to the limited biodegradability of substrate. The PY characteristics was altered due to the decrease of volatiles with AD time. The energy recovery decreased first and then increased, and tended to be stable on day 25–30 (About 11–12 MJ/kg). Cumulative methane production was the crucial factor for coupling time node with a correlation coefficient of 0.9299–0.9278. This study provides theoretical guidance and insights for efficient energy recovery from integrated AD and PY.