umu.sePublications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Characterization of spent spinel-based refractory lining from a 3 MW black liquor gasifier
Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
(English)Manuscript (preprint) (Other academic)
Abstract [en]

Black liquor gasification is dependent on minimizing heat loss to the surroundings and thus needs to be well insulated. In combination with the high temperature and basic black liquor, a very corrosive environment is created on the hot face of such a reactor. Therefore the wall system is required to be chemically and thermally stable at the same time as it has insulating properties. These cannot easily be combined in the same material and therefore layers with different properties can be used in combination. Penetration of species through the lining can lead to further reactions with other construction materials, less suited for chemical resistance, corrosion of the pressure shell is an example with catastrophic consequences. This paper investigates two castable and one fused cast spinel (MgAl2O4) refractory after about 1 600 hours, and one fused cast material used for 15 000 hours of operation in a 3 MWth black liquor gasifier. Infiltration of Na, followed by destruction of microstructure, and extensive formation of NaAlO2 was observed throughout the whole castable materials, while it was mainly restricted to the hot face of the fused cast materials. Formation of NaAlO2 leads to a volumetric expansion which eventually lead to an increased pressure on the steel shell. In addition, the expansion of the bricks can cause stress and by that spallation and material loss.

Keywords [en]
Refractory corrosion, black liquor, gasification, spinel
National Category
Ceramics
Research subject
Materials Science
Identifiers
URN: urn:nbn:se:umu:diva-152662OAI: oai:DiVA.org:umu-152662DiVA, id: diva2:1256549
Available from: 2018-10-17 Created: 2018-10-17 Last updated: 2018-10-18
In thesis
1. Refractory corrosion in biomass gasification
Open this publication in new window or tab >>Refractory corrosion in biomass gasification
2018 (English)Doctoral thesis, comprehensive summary (Other academic)
Alternative title[sv]
Korrosion av eldfasta material i biomassaförgasning
Abstract [en]

To stop the net emission of CO2 to the atmosphere, we need to reduce our dependency of fossil fuels. Although a switch to a bio-based feedstock hardly can replace the total amount of fossils used today, utilization of biomass does still have a role in a future in combination with other techniques. Valuable chemicals today derived from fossils can also be produced from biomass with similar or new technology. One such technique is the entrained flow gasification where biomass is converted into synthesis gas. This gas can then be used as a building stone to produce a wide range of chemicals.

Slagging and corrosion problems are challenges presented by the ash forming elements in biomass during thermochemical energy conversion. The high temperature in the entrained flow process together with ash forming elements is creating a harsh environment for construction materials in the reactor. Severe corrosion and high wear rates of the lining material is a hurdle that has to be overcome to make the process more efficient.

The objective of this work is to investigate the nature of the destructive interaction between ash forming elements and refractory materials to provide new knowledge necessary for optimal refractory choice in entrained flow gasification of woody biomass. This has been done by studying materials exposed to slags in both controlled laboratory environments and pilot scale trials. Morphology, elemental composition and distribution of refractories and slag were investigated with scanning electron microscopy and energy dispersive X-ray spectroscopy. Crystalline phases were investigated with X-ray diffraction, and thermodynamic equilibrium calculations were done in efforts to explain and make predictions of the interaction between slag and refractory.

Observations of slag infiltration and formation of new phases in porous materials indicate severe deterioration. The presence of Si in the materials is limiting intrusion by increasing the viscosity of infiltrated slag. This is however only a temporary delay of severe wear considering the large amount of slag that is expected to pass the refractory surface. Zircon (or zirconium) (element or mineral?) based material show promising properties when modeled with thermodynamic equilibrium, but disassembling of sintered material and dissociation of individual grains was seen after exposure to a Si- and Ca-rich slag. Fused cast materials have a minimal slag contact where the only interaction is on the immediate hot face. Dissolution was however observed when exposed to a silicate-based slag, as was the formation of NaAlO2 after contact with black liquor.

Place, publisher, year, edition, pages
Umeå: Umeå Universitet, 2018. p. 62
Keywords
Refractory corrosion, slag, biomass, gasification
National Category
Energy Engineering
Research subject
Materials Science
Identifiers
urn:nbn:se:umu:diva-152664 (URN)978-91-7601-944-3 (ISBN)
Public defence
2018-11-09, Hörsal N360, Naturvetarhuet, Johan Bures väg 16, Umeå, 13:00 (Swedish)
Opponent
Supervisors
Available from: 2018-10-19 Created: 2018-10-17 Last updated: 2018-10-18Bibliographically approved

Open Access in DiVA

No full text in DiVA

Authority records BETA

Carlborg, MarkusBackman, Rainer

Search in DiVA

By author/editor
Carlborg, MarkusBackman, Rainer
By organisation
Department of Applied Physics and Electronics
Ceramics

Search outside of DiVA

GoogleGoogle Scholar

urn-nbn

Altmetric score

urn-nbn
Total: 122 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf