Fuel characteristics of sewage sludge using thermal treatment

  • Joo Yeob Lee
  • Sujeeta Karki
  • Jeeban Poudel
  • Keun Won Lee
  • Sea Cheon OhEmail author


Pretreatment of sewage sludge under inert condition can produce enhanced solid fuel qualities. In this study, sewage sludge was torrefied in a horizontal tubular reactor at temperatures ranging from 200 to 450 °C. Improved fuel characteristics with reduced oxidized compounds which become more like coal were depicted by the CHO index and Van Krevelen diagram. The CHO index based on molecular C, H, and O data obtained for 450 °C was − 0.65. Statistical Grindability Index (SGI) gradually decreased with the lowest value for 450 °C while the fuel ratio increased with increase in torrefaction temperature. The spontaneous combustion of sewage sludge was analyzed and the average spontaneous combustion temperature of 211.4 °C was obtained.


Sewage sludge Torrefaction CHO index Statistical grindability index (SGI) Spontaneous combustion 



This work was supported by Renewable Energy’s Technology Development Program (No. 20163010102160) of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) funded by the Ministry of Trade, Industry, and Energy of the Korean government and the research project funded by Korea Occupational Safety & Health Agency.


  1. 1.
    Wang G, Luo Y, Deng J, Kuang J, Zhang Y (2011) Pretreatment of biomass by torrefaction. Chin Sci Bull 56:1442–1448CrossRefGoogle Scholar
  2. 2.
    Arias B, Pevida C, Fermoso J, Plaza MG, Rubiera F, Pis J (2008) Influence of torrefaction on the grindability and reactivity of woody biomass. Fuel Process Technol 89:169–175CrossRefGoogle Scholar
  3. 3.
    Chew J, Doshi V (2011) Recent advances in biomass pretreatment–Torrefaction fundamentals and technology. Renew Sust Energy Rev 15:4212–4222CrossRefGoogle Scholar
  4. 4.
    Shankar Tumuluru J, Sokhansanj S, Hess JR, Wright CT, Boardman RD (2011) A review on biomass torrefaction process and product properties for energy applications. Ind Biotechnol 7:384–401CrossRefGoogle Scholar
  5. 5.
    Deutmeyer M, Bradley D, Hektor B, Hess R, Nikolaisen L, Tumuluru J, Wild M (2012) Possible effect of torrefaction on biomass trade. IEA Bioenergy 40Google Scholar
  6. 6.
    Dhungana A, Dutta A, Basu P (2012) Torrefaction of non-lignocellulose biomass waste. Can J Chem Eng 90:186–195CrossRefGoogle Scholar
  7. 7.
    Chen W, Lu K, Tsai C (2012) An experimental analysis on property and structure variations of agricultural wastes undergoing torrefaction. Appl Energy 100:318–325CrossRefGoogle Scholar
  8. 8.
    Asadullah M, Adi AM, Suhada N, Malek NH, Saringat MI, Azdarpour A (2014) Optimization of palm kernel shell torrefaction to produce energy densified bio-coal. Energy Convers Manag 88:1086–1093CrossRefGoogle Scholar
  9. 9.
    Prins MJ, Ptasinski KJ, Janssen FJ (2006) Torrefaction of wood: Part 1. Weight loss kinetics. J Anal Appl Pyrol 77:28–34CrossRefGoogle Scholar
  10. 10.
    Bridgeman T, Jones J, Shield I, Williams P (2008) Torrefaction of reed canary grass, wheat straw and willow to enhance solid fuel qualities and combustion properties. Fuel 87:844–856CrossRefGoogle Scholar
  11. 11.
    Sadaka S, Negi S (2009) Improvements of biomass physical and thermochemical characteristics via torrefaction process. Environ Prog Sustain Energy 28:427–434CrossRefGoogle Scholar
  12. 12.
    Sukiran MA (2008) Pyrolysis of empty oil palm fruit bunches using the quartz fluidised-fixed bed reactor, Master Thesis, University of MalayaGoogle Scholar
  13. 13.
    Almeida G, Brito J, Perré P (2010) Alterations in energy properties of eucalyptus wood and bark subjected to torrefaction: the potential of mass loss as a synthetic indicator. Bioresour Technol 101:9778–9784CrossRefGoogle Scholar
  14. 14.
    Chin K, H’ng P, Go W, Wong W, Lim T, Maminski M, Paridah M, Luqman A (2013) Optimization of torrefaction conditions for high energy density solid biofuel from oil palm biomass and fast growing species available in Malaysia. Ind Crops Prod 49:768–774CrossRefGoogle Scholar
  15. 15.
    Chen W, Peng J, Bi XT (2015) A state-of-the-art review of biomass torrefaction, densification and applications. Renew Sustain Energy Rev 44:847–866CrossRefGoogle Scholar
  16. 16.
    Williams PT, Besler S (1996) The influence of temperature and heating rate on the slow pyrolysis of biomass. Renew Energy 7:233–250CrossRefGoogle Scholar
  17. 17.
    Bergman PC, Boersma A, Zwart R, Kiel J (2005) Torrefaction for biomass co-firing in existing coal-fired power stations. Energy Centre of Netherlands, Report No.ECN-C-05-013. Energy Research Centre of Netherlands (ECN), The NetherlandsGoogle Scholar
  18. 18.
    Uemura Y, Omar WN, Tsutsui T, Yusup SB (2011) Torrefaction of oil palm wastes. Fuel 90:2585–2591CrossRefGoogle Scholar
  19. 19.
    Poudel J, Ohm T, Lee S, Oh SC (2015) A study on torrefaction of sewage sludge to enhance solid fuel qualities. Waste Manag 40:112–118CrossRefGoogle Scholar
  20. 20.
    Sluiter A, Hames B, Ruiz R, Scarlata C, Sluiter J, Templeton D (2004) Determination of ash in biomass: LAP-005 NREL analytical procedure. Natl Renew Energy LabGoogle Scholar
  21. 21.
    Prins MJ (2005) Thermodynamic analysis of biomass gasification and torrefaction, PhD Thesis, Technische Universiteit Eindhoven, The NetherlandsGoogle Scholar
  22. 22.
    Judex JW, Gaiffi M, Burgbacher HC (2012) Gasification of dried sewage sludge: status of the demonstration and the pilot plant. Waste Manag 32:719–723CrossRefGoogle Scholar
  23. 23.
    Nachenius R, van de Wardt T, Ronsse F, Prins W (2015) Torrefaction of pine in a bench-scale screw conveyor reactor. Biomass Bioenergy 79:96–104CrossRefGoogle Scholar
  24. 24.
    Mann BF, Chen H, Herndon EM, Chu RK, Tolic N, Portier EF, Chowdhury TR, Robinson EW, Callister SJ, Wullschleger SD (2015) Indexing permafrost soil organic matter degradation using high-resolution mass spectrometry. PLoS One 10, e0130557Google Scholar
  25. 25.
    Cai J, He Y, Yu X, Banks SW, Yang Y, Zhang X, Yu Y, Liu R, Bridgwater AV (2017) Review of physicochemical properties and analytical characterization of lignocellulosic biomass. Renew Sustain Energy Rev 76:309–322CrossRefGoogle Scholar
  26. 26.
    Poudel J, Karki S, Oh S (2018) Valorization of waste wood as a solid fuel by torrefaction. Energies 11:1641CrossRefGoogle Scholar
  27. 27.
    Felfli FF, Luengo CA, Suárez JA, Beatón PA (2005) Wood briquette torrefaction. Energy Sustain Dev 9:19–22CrossRefGoogle Scholar
  28. 28.
    Bergman PCA, Boersma AR, Kiel JH, Prins MJ, Ptasinski KJ, Janssen F (2004) Torrefaction for entrained-flow gasification of biomass. Report ECN-RX-04-046. ECN, PettenGoogle Scholar
  29. 29.
    Sengupta AN (2002) An assessment of grindability index of coal. Fuel Process Technol 76:1–10CrossRefGoogle Scholar
  30. 30.
    Granados D, Basu P, Chejne F, Nhuchhen D (2016) Detailed investigation into torrefaction of wood in a two-stage inclined rotary torrefier. Energy Fuels 31:647–658CrossRefGoogle Scholar
  31. 31.
    Hardgrove R (1932) Grindability of coal. Trans ASME Fuels Steam Power 54:37–46Google Scholar
  32. 32.
    Silva M, Nebra S, Silva MM, Sanchez C (1998) The use of biomass residues in the Brazilian soluble coffee industry. Biomass Bioenerg 14:457–467CrossRefGoogle Scholar

Copyright information

© Springer Japan KK, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Occupational Safety & Health Research Institute, KOSHADaejeonRepublic of Korea
  2. 2.Department of Environmental EngineeringKongju National UniversitySeobukRepublic of Korea
  3. 3.Waste & Biomass Energy Technology CenterKongju National UniversitySeobukRepublic of Korea

Personalised recommendations