Influence of Pyrolysis Temperature on Product Distribution and Characteristics of Anaerobic Sludge

• Main Authors: Muhammad Usman Hanif, Mohammed Zwawi, Sergio C. Capareda, Hamid Iqbal, Mohammed Algarni, Bassem F. Felemban, Ali Bahadar, Adeel Waqas
• Format: Article
• Language: English
• Published: MDPI AG 2019-12-01
• Series: Energies
• Subjects: anaerobic sludge; pyrolysis; hydrocarbon; alternate energy; bio-oil
• Online Access: https://www.mdpi.com/1996-1073/13/1/79

Pyrolysis of anaerobically digested sludge can serve as an efficient biomass for biofuel production. Pyrolysis produces products like char, bio-oil, and combustible gases by thermochemical conversion process. It can be used for sludge treatment that decreases sludge disposal problems. Sludge produced from anaerobic co-digestion (microalgae, cow dung, and paper) waste has high carbon and hydrogen content. We investigated the candidacy of the anaerobic sludge having high heating value (HHV) of 20.53 MJ/kg as a reliable biomass for biofuels production. The process of pyrolysis was optimized with different temperatures (400, 500, and 600 °C) to produce high quantity and improved quality of the products, mainly bio-oil, char, and gas. The results revealed that with the increase in pyrolysis temperature the quantity of char decreased (81% to 55%), bio-oil increased (3% to 7%), and gas increased (2% to 5%). The HHV of char (19.2 MJ/kg), bio-oil (28.1 MJ/kg), and gas (18.1 MJ/kg) were predominantly affected by the amount of fixed carbon, hydrocarbons, and volatile substance, respectively. The study confirmed that the anaerobic sludge is a promising biomass for biofuel production and pyrolysis is an efficient method for its safe disposal.