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. © 2021 The Author(s)
Place, publisher, year, edition, pages
Elsevier B.V. , 2021. Vol. 217, article id 106805
Keywords [en]
Agricultural biomass fuels, Ash transformation, Gasification, Phosphorus, Potassium, Release, Biomass, Calcium compounds, Fuels, Grain (agricultural product), Magnesium compounds, Pelletizing, Silicates, Agricultural biomass, Agricultural biomass fuel, Bio-energy systems, Deposit formation, Residual ash, Residual char, Transformation Reactions, Wheat grains
National Category
Energy Engineering
Identifiers
URN: urn:nbn:se:ri:diva-52623DOI: 10.1016/j.fuproc.2021.106805Scopus ID: 2-s2.0-85102537881OAI: oai:DiVA.org:ri-52623DiVA, id: diva2:1539792
Note
Funding details: Svenska Forskningsrådet Formas, 2017-01613; Funding details: Vetenskapsrådet, VR, 2016-04380; Funding details: Energimyndigheten, 41877-1; Funding text 1: The financial support from the ERA-NET Bioenergy for the GrateAdvance project (Swedish Energy Agency, Sweden project number 41877-1) and the Swedish Research Council, Sweden, project 2016-04380 are gratefully acknowledged. Further, Nils Skoglund gratefully acknowledges the financial support from the FORMAS project 2017-01613, Sweden. We thank prof. Klaus Hack (GTT Technologies), Dr. Moritz to Baben (GTT Technologies), and Prof. Rainer Backman (Ume? University) for productive discussion regarding thermodynamic equilibrium calculations.
2021-03-252021-03-252021-03-25Bibliographically approved