Chinese Journal of Chemical Engineering ›› 2020, Vol. 28 ›› Issue (1): 293-298.doi: 10.1016/j.cjche.2019.08.004

• Energy, Resources and Environmental Technology • Previous Articles     Next Articles

Improving supercritical water gasification of sludge by oil palm empty fruit bunch addition: Promotion of syngas production and heavy metal stabilization

Zhouchao Weng1, Ekkachai Kanchanatip1,3, Dwi Hantoko1,2, Mi Yan1, Hongcai Su1, Sicheng Zhang1, Guobin Wang1   

  1. 1 Institute of Energy and Power Engineering, Zhejiang University of Technology, Hangzhou 310014, China;
    2 Department of Chemical Engineering, Institut Teknologi Bandung, Bandung 40132, Indonesia;
    3 Center of Excellence in Environmental Catalysis and Adsorption, Faculty of Engineering, Thammasat University, Pathumthani 12120, Thailand
  • Received:2019-04-25 Revised:2019-07-28 Online:2020-01-28 Published:2020-03-31
  • Contact: Mi Yan

Abstract: The co-gasification of sewage sludge and palm oil empty fruit bunch (EFB) in supercritical water (SCW) was conducted at 400℃ with a pressure of over 25 MPa. This study aimed to investigate the influence of EFB addition on the syngas production and its composition. The heavy metal distribution and the leaching potential of the solid residue were also assessed. The results showed that syngas yield significantly increased with the addition of EFB into the feedstock. The cold gas efficiency (CGE) and carbon efficiency (CE) of co-gasification were higher than those of individual gasification. The actual syngas production from co-gasification of sludge and EFB was 45% higher than the theoretical total volume. The results indicated that the addition of EFB to sludge had the synergetic promotion effect on syngas production from sludge and EFB in supercritical water. This enhancement might be due to the dissolution of alkali metals from EFB and the adjustment of organic ratio. In addition, higher percentage of heavy metals were deposited and stabilized in the solid residue after SCWG. The leaching concentration of heavy metals from the solid residues was decreased to a level below the standard limit which enables it to be safely disposed of in landfill. In conclusion, the EFB addition has been proved to promote syngas production, as well as, stabilize the heavy metal in solid residues during co-SCWG.

Key words: Co-gasification, Supercritical water, Sludge, Empty fruit bunch, Syngas, Heavy metal