Ash transformation during single-pellet gasification of agricultural biomass with focus on potassium and phosphorusShow others and affiliations
2021 (English)In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 217, article id 106805Article in journal (Refereed) Published
Abstract [en]
Agricultural biomasses and residues can play an important role in the global bioenergy system but their potential is limited by the risk of several ash-related problems such as deposit formation, slagging, and particle emissions during their thermal conversion. Therefore, a thorough understanding of the ash transformation reactions is required for this type of fuels. The present work investigates ash transformation reactions and the release of critical ash-forming elements with a special focus on K and P during the single-pellet gasification of different types of agricultural biomass fuels, namely, poplar, grass, and wheat grain residues. Each fuel was gasified as a single pellet at three different temperatures (600, 800, and 950 °C) in a Macro-TGA reactor. The residues from different stages of fuel conversion were collected to study the gradual ash transformation. Characterization of the residual char and ash was performed employing SEM-EDS, XRD, and ICP with the support of thermodynamic equilibrium calculations (TECs). The results showed that the K and P present in the fuels were primarily found in the residual char and ash in all cases for all studied fuels. While the main part of the K release occurred during the char conversion stage, the main part of the P release occurred during the devolatilization stage. The highest releases – less than 18% of P and 35% of K – were observed at the highest studied temperature for all fuels. These elements were present in the residual ashes as K2Ca(CO3)2 and Ca5(PO4)3OH for poplar; K-Ca-rich silicates and phosphosilicates in mainly amorphous ash for grass; and an amorphous phase rich in K-Mg-phosphates for wheat grain residues.
Place, publisher, year, edition, pages
Elsevier, 2021. Vol. 217, article id 106805
Keywords [en]
Agricultural biomass fuels, Ash transformation, Gasification, Phosphorus, Potassium, Release
National Category
Bioenergy Energy Engineering
Identifiers
URN: urn:nbn:se:umu:diva-181784DOI: 10.1016/j.fuproc.2021.106805ISI: 000647475600010Scopus ID: 2-s2.0-85102537881OAI: oai:DiVA.org:umu-181784DiVA, id: diva2:1541592
Funder
Swedish Research Council Formas, 2017-01613Swedish Research Council, 2016-04380Swedish Energy Agency, 41877-12021-04-012021-04-012024-07-02Bibliographically approved