Pyrolysis study of hydrothermal carbonization-treated digested sewage sludge using a Py-GC/MS and a bench-scale pyrolyzer

• The disposal of digested sewage sludge is becoming a global problem. Hydrothermal carbonization (HTC) combined with the pyrolysis of digested sewage sludge was investigated by using a new conversion route for the exploitation of sewage sludge in energy applications. The thermochemical properties of the material were investigated by using HTC pre-treatments, thermogravimetric analyses, pyrolysis tests in Py-GC/MS and a bench-scale fixed bed reactor at temperatures of 450, 550, and 650 °C. It was found that the thermal decomposition of the hydrothermally treated digested sewage sludge takes place in a two-stage reaction. After pyrolysis, the ash in the sample was oxidized in the O2 atmosphere at 900 °C. Therefore, a new characterization method for determination of the non-oxdized ash content and fixed carbon content was proposed. The result from Py-GC/MS shows that the abundance of aromatic hydrocarbons in pyrolytic vapors present a positive correlation with increased temperature. In the bench-scale experiments, the highest HHV of the organic fraction was obtained at 650 °C as 38.46 MJ/kg. 

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Industriell bioteknik -- Bioenergi (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Industrial Biotechnology -- Bioenergy (hsv//eng)

Nyckelord

Ash content determination

Biofuel

Digested sewage sludge

HTC

Pyrolysis

Aromatic hydrocarbons

Biofuels

Carbonization

Chemical analysis

Chemical reactors

Sewage sludge

Thermochemistry

Thermogravimetric analysis

Ash contents

Bench scale experiments

Characterization methods

Hydrothermal carbonization

Hydrothermally treated

Positive correlations

Thermochemical properties

Sludge disposal

Chemical Engineering

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