Diploma Thesis Defense by Mr. Kolosionis Agelos
09/19/2019
Thesis Title: «Conversion of sewage sludge to clean solid fuel using pyrolysis and washing»
Wednesday 12 February 2020, at: 12:00, Venue: Hall Κ2.Α11
Examination Committee
- Assistant Professor Apostolos Giannis (advisor)
- Professor Evagelos Gidarakos
- Assistant Professor Paraskevi Panagiotopoulou
Abstract
Sewage sludge biochars were produced by pyrolysis followed by washing in order to increase the yield of clean solid fuel. The physicochemical transformation of sewage sludge was studied during pyrolysis at different carbonization temperatures (400-700oC). The produced biochars were then subjected to washing by deionized water (W), hydrochloric acid (HCl), ethylenediamine tetraacetic acid (EDTA) and deionized water-ultrasound (US) to further reduce ash and heavy metals content. The washed biochars were further characterized and compared to non-processed biochars in order to assess the fuel properties. All washing procedures decreased the ash and heavy metals content and improved the fuel ratio (FR). Also, the washed biochars exhibited higher heating values, lower slagging and ash fouling indexes and higher combustion reactivity, indicating that higher quality fuels were obtained. Among the washing test, HCl washing was the most efficient process. In conclusion, pyrolysis as a single process is inefficient to produce high yield biochars, however coupling pyrolysis and washing produce biochars with advanced fuel properties.
