Ash transformation during single-pellet gasification of sewage sludge and mixtures with agricultural residues with a focus on phosphorus

Hannl, Thomas Karl,M.Sc.1993-Luleå tekniska universitet,Energivetenskap,Energy Engineering, Division of Energy Science, Luleå University of Technology, Luleå, Sweden (författare)

Validerad;2022;Nivå 2;2022-03-02 (hanlid)
The recovery of phosphorus (P) from sewage sludge ashes has been the focus of recent research due to the initiatives for the use of biogenic resources and resource recovery. This study investigates the ash transformation chemistry of P in sewage sludge ash during the co-gasification with the K-Si- and K-rich agricultural residues wheat straw and sunflower husks, respectively, at temperatures relevant for fluidized bed technology, namely 800 °C and 950 °C. The residual ash was analyzed by ICPAES, SEM/EDS, and XRD, and the results were compared to results of thermochemical equilibrium calculations. More than 90% of P and K in the fuels were retained in the residual ash fraction, and significant interaction phenomena occurred between the P-rich sewage sludge and the K-rich ash fractions. Around 45–65% of P was incorporated in crystalline K-bearing phosphates, i.e., K-whitlockite and CaKPO4, in the residual ashes with 85–90 wt% agricultural residue in the fuel mixture. In residual ashes of sewage sludge and mixtures with 60–70 wt% agricultural residue, P was mainly found in Ca(Mg,Fe)-whitlockites and AlPO4. Up to about 40% of P was in amorphous or unidentified phases. The results show that gasification provides a potential for the formation of K-bearing phosphates similar to combustion processes.

Häggström, GustavLuleå tekniska universitet,Energivetenskap,Energy Engineering, Division of Energy Science, Luleå University of Technology, Luleå, Sweden(Swepub:ltu)gushag (författare)
Hedayati, Ali,1984-Luleå tekniska universitet,Energivetenskap,Energy Engineering, Division of Energy Science, Luleå University of Technology, Luleå, Sweden(Swepub:ltu)alihed (författare)
Skoglund, NilsUmeå universitet,Institutionen för tillämpad fysik och elektronik,Department of Applied Physics and Electronics, Umeå University, SE-901 87 Umeå, Sweden; Institute of Chemical, Environmental & Bioscience Engineering, TU Wien, AT-1060 Vienna, Austria; BEST - Bioenergy and Sustainable Technologies GmbH, Inffeldgasse 21b, AT-8010 Graz, Austria(Swepub:umu)nisskd01 (författare)
Kuba, MatthiasInstitute of Chemical, Environmental & Bioscience Engineering, TU Wien, AT-1060 Vienna, Austria; BEST - Bioenergy and Sustainable Technologies GmbH, Inffeldgasse 21b, AT-8010 Graz, Austria (författare)
Öhman, Marcus,1969-Luleå tekniska universitet,Energivetenskap,Energy Engineering, Division of Energy Science, Luleå University of Technology, Luleå, Sweden(Swepub:ltu)ohmmar (författare)
Luleå tekniska universitetEnergivetenskap (creator_code:org_t)

Av författaren/redakt...: Hannl, Thomas Ka ...; Häggström, Gusta ...; Hedayati, Ali, 1 ...; Skoglund, Nils; Kuba, Matthias; Öhman, Marcus, 1 ...

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