Research on morphological characteristics of sewage sludge pyrolysis process

Sewage sludge corresponds to some special morphological characteristics during its pyrolysis process. In this paper, photographic images of sewage sludge during its pyrolysis under 400°C were sampled for the whole process to identify its different stages. Digital image processing technology has been applied to obtain the quantitative morphological characteristics of these photographs; the relevance of these characteristics and the pyrolysis process is also discussed. It has been found that both the main area of sewage sludge layer and the optical densities of channels R(red), G(green) and B(Blue) reduce with the pyrolysis process, and the optical densities are closely related to the pyrolysis stages. Also by analyzing experimental data the changing curve of averaged optical density of RGB with reaction time is found to satisfy DoseResp function, which provides an innovative method for automatic control of sewage sludge pyrolysis process.