Protective Power of Coal and Peat against Alkali Chloride Formation and Cl Deposition in Blends with Forest Biomass in FBC

Timo Leino, Martti Aho (Corresponding author), Juho Kauppinen, Merja Hedman, Joni Maunula, Juha Roppo

Research output: Contribution to conferenceConference articleScientificpeer-review

Abstract

The capacity of two coals and one peat to protect the exposed metal surface against alkali chloride deposition and to decrease alkali chlorides concentration in the furnace when blended with forest residues were determined in pilot-scale bubbling bed (15 kW) and circulating fluidised bed (60 kW) reactors of VTT by combining advanced measurement techniques in an unique way. Mass impactor (LPI) sampling was followed by analysis of Na, K, S and Cl and Collinear Photofragmentation and Atomic Absorption Spectroscopy (CPFAAS) was used to real-time KCl determination. In addition, deposits were collected on temperature controlled probes (superheater simulators) and analysed afterwards with SEM EDXA at various positions.The highest alkali chloride vapour concentration existing at the upper furnace without measured Cl deposition was obtained. Presence of alkali chlorides at upper parts of the furnace was possible during 100% forest biomass firing due to weak reactions to convert alkali chlorides to HCl. However, some degree of sulphation of alkali chlorides was found.The order of capacity against alkali chlorides formation and Cl deposition was coal 2 > coal 1 > peat. At pilot-plant tests, where the blend composition can be better controlled than in power plants, addition of coal 2 allowed almost 90% forest biomass (on energy basis) to the blends without Cl deposition. Combustion technology (BFB or CFB) did not have measurable effect on alkali chlorides flow in the furnace with identical fuel, but highest Cl concentrations in deposits (up to 13 wt% at side position with 100% forest biomass) were obtained at CFB conditions. Such Cl concentration does not only form firm superheater deposits but what is more critical probably starts metal corrosion.
Original languageEnglish
Publication statusPublished - 2015
MoE publication typeNot Eligible
Event22nd International Conference on Fluidized Bed Conversion, FBC 2015 - Turku, Finland
Duration: 14 Jun 201517 Jun 2015
Conference number: 22

Conference

Conference22nd International Conference on Fluidized Bed Conversion, FBC 2015
Abbreviated titleFBC 2015
CountryFinland
CityTurku
Period14/06/1517/06/15

Fingerprint

peat
chloride
coal
biomass
metal
atomic absorption spectroscopy
simulator
corrosion
power plant
combustion
scanning electron microscopy
probe
furnace
sampling
energy
temperature

Keywords

  • Deposition, chlorides, co-firing, furnace measurements

Cite this

Leino, T., Aho, M., Kauppinen, J., Hedman, M., Maunula, J., & Roppo, J. (2015). Protective Power of Coal and Peat against Alkali Chloride Formation and Cl Deposition in Blends with Forest Biomass in FBC. Paper presented at 22nd International Conference on Fluidized Bed Conversion, FBC 2015, Turku, Finland.
Leino, Timo ; Aho, Martti ; Kauppinen, Juho ; Hedman, Merja ; Maunula, Joni ; Roppo, Juha. / Protective Power of Coal and Peat against Alkali Chloride Formation and Cl Deposition in Blends with Forest Biomass in FBC. Paper presented at 22nd International Conference on Fluidized Bed Conversion, FBC 2015, Turku, Finland.
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title = "Protective Power of Coal and Peat against Alkali Chloride Formation and Cl Deposition in Blends with Forest Biomass in FBC",
abstract = "The capacity of two coals and one peat to protect the exposed metal surface against alkali chloride deposition and to decrease alkali chlorides concentration in the furnace when blended with forest residues were determined in pilot-scale bubbling bed (15 kW) and circulating fluidised bed (60 kW) reactors of VTT by combining advanced measurement techniques in an unique way. Mass impactor (LPI) sampling was followed by analysis of Na, K, S and Cl and Collinear Photofragmentation and Atomic Absorption Spectroscopy (CPFAAS) was used to real-time KCl determination. In addition, deposits were collected on temperature controlled probes (superheater simulators) and analysed afterwards with SEM EDXA at various positions.The highest alkali chloride vapour concentration existing at the upper furnace without measured Cl deposition was obtained. Presence of alkali chlorides at upper parts of the furnace was possible during 100{\%} forest biomass firing due to weak reactions to convert alkali chlorides to HCl. However, some degree of sulphation of alkali chlorides was found.The order of capacity against alkali chlorides formation and Cl deposition was coal 2 > coal 1 > peat. At pilot-plant tests, where the blend composition can be better controlled than in power plants, addition of coal 2 allowed almost 90{\%} forest biomass (on energy basis) to the blends without Cl deposition. Combustion technology (BFB or CFB) did not have measurable effect on alkali chlorides flow in the furnace with identical fuel, but highest Cl concentrations in deposits (up to 13 wt{\%} at side position with 100{\%} forest biomass) were obtained at CFB conditions. Such Cl concentration does not only form firm superheater deposits but what is more critical probably starts metal corrosion.",
keywords = "Deposition, chlorides, co-firing, furnace measurements",
author = "Timo Leino and Martti Aho and Juho Kauppinen and Merja Hedman and Joni Maunula and Juha Roppo",
year = "2015",
language = "English",
note = "22nd International Conference on Fluidized Bed Conversion, FBC 2015, FBC 2015 ; Conference date: 14-06-2015 Through 17-06-2015",

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Leino, T, Aho, M, Kauppinen, J, Hedman, M, Maunula, J & Roppo, J 2015, 'Protective Power of Coal and Peat against Alkali Chloride Formation and Cl Deposition in Blends with Forest Biomass in FBC' Paper presented at 22nd International Conference on Fluidized Bed Conversion, FBC 2015, Turku, Finland, 14/06/15 - 17/06/15, .

Protective Power of Coal and Peat against Alkali Chloride Formation and Cl Deposition in Blends with Forest Biomass in FBC. / Leino, Timo; Aho, Martti (Corresponding author); Kauppinen, Juho; Hedman, Merja; Maunula, Joni; Roppo, Juha.

2015. Paper presented at 22nd International Conference on Fluidized Bed Conversion, FBC 2015, Turku, Finland.

Research output: Contribution to conferenceConference articleScientificpeer-review

TY - CONF

T1 - Protective Power of Coal and Peat against Alkali Chloride Formation and Cl Deposition in Blends with Forest Biomass in FBC

AU - Leino, Timo

AU - Aho, Martti

AU - Kauppinen, Juho

AU - Hedman, Merja

AU - Maunula, Joni

AU - Roppo, Juha

PY - 2015

Y1 - 2015

N2 - The capacity of two coals and one peat to protect the exposed metal surface against alkali chloride deposition and to decrease alkali chlorides concentration in the furnace when blended with forest residues were determined in pilot-scale bubbling bed (15 kW) and circulating fluidised bed (60 kW) reactors of VTT by combining advanced measurement techniques in an unique way. Mass impactor (LPI) sampling was followed by analysis of Na, K, S and Cl and Collinear Photofragmentation and Atomic Absorption Spectroscopy (CPFAAS) was used to real-time KCl determination. In addition, deposits were collected on temperature controlled probes (superheater simulators) and analysed afterwards with SEM EDXA at various positions.The highest alkali chloride vapour concentration existing at the upper furnace without measured Cl deposition was obtained. Presence of alkali chlorides at upper parts of the furnace was possible during 100% forest biomass firing due to weak reactions to convert alkali chlorides to HCl. However, some degree of sulphation of alkali chlorides was found.The order of capacity against alkali chlorides formation and Cl deposition was coal 2 > coal 1 > peat. At pilot-plant tests, where the blend composition can be better controlled than in power plants, addition of coal 2 allowed almost 90% forest biomass (on energy basis) to the blends without Cl deposition. Combustion technology (BFB or CFB) did not have measurable effect on alkali chlorides flow in the furnace with identical fuel, but highest Cl concentrations in deposits (up to 13 wt% at side position with 100% forest biomass) were obtained at CFB conditions. Such Cl concentration does not only form firm superheater deposits but what is more critical probably starts metal corrosion.

AB - The capacity of two coals and one peat to protect the exposed metal surface against alkali chloride deposition and to decrease alkali chlorides concentration in the furnace when blended with forest residues were determined in pilot-scale bubbling bed (15 kW) and circulating fluidised bed (60 kW) reactors of VTT by combining advanced measurement techniques in an unique way. Mass impactor (LPI) sampling was followed by analysis of Na, K, S and Cl and Collinear Photofragmentation and Atomic Absorption Spectroscopy (CPFAAS) was used to real-time KCl determination. In addition, deposits were collected on temperature controlled probes (superheater simulators) and analysed afterwards with SEM EDXA at various positions.The highest alkali chloride vapour concentration existing at the upper furnace without measured Cl deposition was obtained. Presence of alkali chlorides at upper parts of the furnace was possible during 100% forest biomass firing due to weak reactions to convert alkali chlorides to HCl. However, some degree of sulphation of alkali chlorides was found.The order of capacity against alkali chlorides formation and Cl deposition was coal 2 > coal 1 > peat. At pilot-plant tests, where the blend composition can be better controlled than in power plants, addition of coal 2 allowed almost 90% forest biomass (on energy basis) to the blends without Cl deposition. Combustion technology (BFB or CFB) did not have measurable effect on alkali chlorides flow in the furnace with identical fuel, but highest Cl concentrations in deposits (up to 13 wt% at side position with 100% forest biomass) were obtained at CFB conditions. Such Cl concentration does not only form firm superheater deposits but what is more critical probably starts metal corrosion.

KW - Deposition, chlorides, co-firing, furnace measurements

M3 - Conference article

ER -

Leino T, Aho M, Kauppinen J, Hedman M, Maunula J, Roppo J. Protective Power of Coal and Peat against Alkali Chloride Formation and Cl Deposition in Blends with Forest Biomass in FBC. 2015. Paper presented at 22nd International Conference on Fluidized Bed Conversion, FBC 2015, Turku, Finland.