Quality of deposits during grate combustion of corn stover and wood chip blends

Martti Aho (Corresponding Author), Kari Paakkinen, Raili Taipale

Research output: Contribution to journalArticleScientificpeer-review

29 Citations (Scopus)

Abstract

There is need to increase efficiency of electricity production in grate combustion (GC). This will lead, however, to higher steam temperatures and make superheaters more susceptible to corrosion. Corn stover (CS) is one of the most abundant agro-biomass residues available to energy production on a global scale and GC power plants are best suited to its combustion. The focus in this study was the quality of deposits during GC of CS blended with wood chips. CS is a difficult fuel at least due to its high chlorine content (up to 1 wt%). After a thorough fuel analysis (also with wheat straw, for comparison), combustion tests were conducted with a 100 kW grate reactor, where gas temperature versus residence time can resemble that in a full scale GC power plant furnace. Flue gas composition, alkali chloride mass flow, mass deposition, and deposition of chlorine and other key elements at critical positions of two superheater simulators were measured. Corrosivity of deposit, if estimated only from the maximum chlorine concentration found in deposits, reached maximum already with 20 ± 3% portion of CS on energy basis (which was the lowest portion of CS in the tests). However, further increase of the portion of CS in the blend was found to increase the overall mass deposition and also Cl mass deposition through this way. Because corrosion reactions consume elemental chlorine, the corrosivity (metal loss) at superheater area can increase as a function of CS portion in range >20% CS. Ash problems found on the grate were mostly due to the high mineral content in CS. These minerals originated mainly from the soil (during the harvesting stage), which led to higher ash melting temperatures compared to wheat straw ash.
Original languageEnglish
Pages (from-to)476-487
Number of pages12
JournalFuel
Volume104
DOIs
Publication statusPublished - 2013
MoE publication typeA1 Journal article-refereed

Fingerprint

Ashes
Wood
Deposits
Chlorine
Superheaters
Straw
Minerals
Power plants
Corrosion
Steam
Alkalies
Flue gases
Melting point
Chlorides
Biomass
Furnaces
Electricity
Simulators
Gases
Metals

Keywords

  • Biomass
  • corrosion
  • deposits
  • grate combustion

Cite this

Aho, Martti ; Paakkinen, Kari ; Taipale, Raili. / Quality of deposits during grate combustion of corn stover and wood chip blends. In: Fuel. 2013 ; Vol. 104. pp. 476-487.
@article{cf067aff5d884093b400c4f4e57882b2,
title = "Quality of deposits during grate combustion of corn stover and wood chip blends",
abstract = "There is need to increase efficiency of electricity production in grate combustion (GC). This will lead, however, to higher steam temperatures and make superheaters more susceptible to corrosion. Corn stover (CS) is one of the most abundant agro-biomass residues available to energy production on a global scale and GC power plants are best suited to its combustion. The focus in this study was the quality of deposits during GC of CS blended with wood chips. CS is a difficult fuel at least due to its high chlorine content (up to 1 wt{\%}). After a thorough fuel analysis (also with wheat straw, for comparison), combustion tests were conducted with a 100 kW grate reactor, where gas temperature versus residence time can resemble that in a full scale GC power plant furnace. Flue gas composition, alkali chloride mass flow, mass deposition, and deposition of chlorine and other key elements at critical positions of two superheater simulators were measured. Corrosivity of deposit, if estimated only from the maximum chlorine concentration found in deposits, reached maximum already with 20 ± 3{\%} portion of CS on energy basis (which was the lowest portion of CS in the tests). However, further increase of the portion of CS in the blend was found to increase the overall mass deposition and also Cl mass deposition through this way. Because corrosion reactions consume elemental chlorine, the corrosivity (metal loss) at superheater area can increase as a function of CS portion in range >20{\%} CS. Ash problems found on the grate were mostly due to the high mineral content in CS. These minerals originated mainly from the soil (during the harvesting stage), which led to higher ash melting temperatures compared to wheat straw ash.",
keywords = "Biomass, corrosion, deposits, grate combustion",
author = "Martti Aho and Kari Paakkinen and Raili Taipale",
year = "2013",
doi = "10.1016/j.fuel.2012.05.057",
language = "English",
volume = "104",
pages = "476--487",
journal = "Fuel",
issn = "0016-2361",
publisher = "Elsevier",

}

Quality of deposits during grate combustion of corn stover and wood chip blends. / Aho, Martti (Corresponding Author); Paakkinen, Kari; Taipale, Raili.

In: Fuel, Vol. 104, 2013, p. 476-487.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Quality of deposits during grate combustion of corn stover and wood chip blends

AU - Aho, Martti

AU - Paakkinen, Kari

AU - Taipale, Raili

PY - 2013

Y1 - 2013

N2 - There is need to increase efficiency of electricity production in grate combustion (GC). This will lead, however, to higher steam temperatures and make superheaters more susceptible to corrosion. Corn stover (CS) is one of the most abundant agro-biomass residues available to energy production on a global scale and GC power plants are best suited to its combustion. The focus in this study was the quality of deposits during GC of CS blended with wood chips. CS is a difficult fuel at least due to its high chlorine content (up to 1 wt%). After a thorough fuel analysis (also with wheat straw, for comparison), combustion tests were conducted with a 100 kW grate reactor, where gas temperature versus residence time can resemble that in a full scale GC power plant furnace. Flue gas composition, alkali chloride mass flow, mass deposition, and deposition of chlorine and other key elements at critical positions of two superheater simulators were measured. Corrosivity of deposit, if estimated only from the maximum chlorine concentration found in deposits, reached maximum already with 20 ± 3% portion of CS on energy basis (which was the lowest portion of CS in the tests). However, further increase of the portion of CS in the blend was found to increase the overall mass deposition and also Cl mass deposition through this way. Because corrosion reactions consume elemental chlorine, the corrosivity (metal loss) at superheater area can increase as a function of CS portion in range >20% CS. Ash problems found on the grate were mostly due to the high mineral content in CS. These minerals originated mainly from the soil (during the harvesting stage), which led to higher ash melting temperatures compared to wheat straw ash.

AB - There is need to increase efficiency of electricity production in grate combustion (GC). This will lead, however, to higher steam temperatures and make superheaters more susceptible to corrosion. Corn stover (CS) is one of the most abundant agro-biomass residues available to energy production on a global scale and GC power plants are best suited to its combustion. The focus in this study was the quality of deposits during GC of CS blended with wood chips. CS is a difficult fuel at least due to its high chlorine content (up to 1 wt%). After a thorough fuel analysis (also with wheat straw, for comparison), combustion tests were conducted with a 100 kW grate reactor, where gas temperature versus residence time can resemble that in a full scale GC power plant furnace. Flue gas composition, alkali chloride mass flow, mass deposition, and deposition of chlorine and other key elements at critical positions of two superheater simulators were measured. Corrosivity of deposit, if estimated only from the maximum chlorine concentration found in deposits, reached maximum already with 20 ± 3% portion of CS on energy basis (which was the lowest portion of CS in the tests). However, further increase of the portion of CS in the blend was found to increase the overall mass deposition and also Cl mass deposition through this way. Because corrosion reactions consume elemental chlorine, the corrosivity (metal loss) at superheater area can increase as a function of CS portion in range >20% CS. Ash problems found on the grate were mostly due to the high mineral content in CS. These minerals originated mainly from the soil (during the harvesting stage), which led to higher ash melting temperatures compared to wheat straw ash.

KW - Biomass

KW - corrosion

KW - deposits

KW - grate combustion

U2 - 10.1016/j.fuel.2012.05.057

DO - 10.1016/j.fuel.2012.05.057

M3 - Article

VL - 104

SP - 476

EP - 487

JO - Fuel

JF - Fuel

SN - 0016-2361

ER -