Novel drying process using forced aeration through a porous biomass matrix.

摘要

Laboratory tests were conducted for three sludge/woodwaste mixtures. Data were collected throughout the biopile to monitor temperature, humidity, pressure, airflow, and total mass so that moisture and carbon losses in the sludge could be approximated. The 1:0.5 sludge/woodwaste dry mass-ratio resulted in the best drying rate, providing favorable pneumatic conditions, and resulting in increased sludge dryness from 30.5% to 41.6% in 13 days. Heat generation within the biopile raised the temperatures to peak values as high as 65°C, and increased temperature correlated well with increased rate of water removal. Carbon losses were linked to internal heat generation as well, and total carbon losses ranged from 5.5% to 18% over the 3 runs.; This biodrying process can potentially provide several economic advantages to the mill, namely (1) fuel savings due to the increased calorific value of dried sludge, associated with a reduction in supplemental fuel (typically natural gas and/or oil) to the boiler, (2) reduced or eliminated requirement for sludge landfilling or landspreading, and (3) a reduction in greenhouse gas emissions if biomass combustion is considered net-zero for CO2 emissions.; A techno-economic analysis of the process showed that mills who should most consider this process include those; that already possess woodwaste combustion facilities and related material handling operations, who have space available for multiple biodrying reactors local to existing boilers, who send their sludge offsite for either landfilling or landspreading, and/or who have high fossil fuel costs. The payback period for implementation of this process at the base case mill was about 2.5 years, and the best-case scenarios were found to be less than 1 year. (Abstract shortened by UMI.)