Investigation of biomass alkali release in a dual circulating fluidized bed chemical looping combustion system

Gogolev, Ivan; Pikkarainen, Toni; Kauppinen, Juho; Linderholm, Carl Johan; Steenari, Britt‐Marie; Lyngfelt, Anders

doi:10.1016/j.fuel.2021.120743

Cited by 52 publications

(37 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Indeed, for ilmenite the formation of silicates, aluminosilicates, manganates, and alkali titanates was detected, while for braunite mainly manganates and silicates. However, alkali release can be promoted by steam-rich conditions because the presence of steam accelerates the decomposition of potassium salts with an increased formation and release of KOH(g) . Some differences can also be observed on varying the alkali content in the biomass: fuels with high alkali content determined higher emissions form the FR; in particular, the emissions from the FR were several times higher with respect to the AR.…”

Section: Role Of Biomass Ash and The Fate Of Alkalimentioning

confidence: 75%

“…Few studies focused on the fate of biomass alkali in the gaseous phase. In particular, Gogolev and co-workers ,, focused their attention on alkali emissions at the outlet of CLC system both from the FR and the AR. Despite the fact that a lot of work is necessary for a complete comprehension of how several operating condition may influence the release of alkali, some important findings can be summarized.…”

Section: Role Of Biomass Ash and The Fate Of Alkalimentioning

confidence: 99%

See 1 more Smart Citation

Chemical Looping for Combustion of Solid Biomass: A Review

Coppola¹,

Scala

2021

Energy Fuels

View full text Add to dashboard Cite

Chemical looping combustion of solid biomass has the unique potential to generate energy with negative carbon emissions, while entailing an energy penalty compared to traditional combustion that is lower than that of the competing carbon capture technologies. In spite of these attractive features, research is still needed to bring the technology to a fully commercial level. The reason relies on a number of technological challenges mostly related to the oxygen carrier performance, its possible detrimental interaction with the biomass ash components, and the efficiency of the gas–solid contact with the biomass volatiles. This review is focused on these specific challenges which are particularly relevant when firing biomass rather than coal in a solid-based chemical looping combustion process. Special attention will be given to the most recent findings published on these aspects. Related performance evaluation by modeling, system integration, and techno-economic analysis will also be briefly reviewed.

show abstract

Section: Role Of Biomass Ash and The Fate Of Alkalimentioning

confidence: 75%

Section: Role Of Biomass Ash and The Fate Of Alkalimentioning

confidence: 99%

Chemical Looping for Combustion of Solid Biomass: A Review

Coppola¹,

Scala

2021

Energy Fuels

View full text Add to dashboard Cite

show abstract

“… 24 − 27 Two pilot-scale investigations in continuous CLC systems have looked at effects of alkalis on oxygen carriers, 28 , 29 but only a few studies have attempted to directly measure and determine alkali release to the gas phase and alkali retention in the bed material. 30 − 32 …”

Section: Introductionmentioning

confidence: 99%

“…In the latest study, a comparison of CLC operation to operation of the same pilot system as a circulating fluidized bed boiler with oxygen carrier bed material, the so-called oxygen-carrier-aided combustion (OCAC) mode, showed that OCAC operation results in significantly lower alkali emissions. 32 The higher emissions in CLC operation were suspected to occur as a result of the steam-rich environment in CLC operation.…”

Section: Introductionmentioning

confidence: 99%

Effects of Temperature, Operation Mode, and Steam Concentration on Alkali Release in Chemical Looping Conversion of Biomass─Experimental Investigation in a 10 kW_th Pilot

et al. 2022

Self Cite

View full text Add to dashboard Cite

Alkali release was studied in a 10 kW th chemical looping pilot operated with a Linz–Donawitz (LD) slag oxygen carrier (OC) and three biomass fuels. Experiments were performed at three temperatures and in three operation modes: chemical looping combustion (CLC), chemical looping gasification (CLG), and oxygen-carrier-aided combustion (OCAC). Gas-phase alkali release was measured with a surface ionization detector (SID). Fuel reactor (FR) gas-phase alkali emissions increased with the temperature. This occurred as a result of increased evaporation of KCl and enhanced decomposition of alkali salts during char conversion. Air reactor (AR) alkali emissions were lower than in the FR and independent of the operating temperature. In comparison of operating modes, CLC and CLG modes resulted in similar gas-phase alkali emissions due to the similar extent of char conversion. In contrast, operation of the reactor system in OCAC mode resulted in significantly lower levels of gas-phase alkalis. The difference in alkali emission was attributed to the steam-rich atmosphere of CLC. The effect of steam was further investigated in CLC and OCAC tests. Lowering steam concentrations in CLC operation resulted in lower gas-phase alkali emissions, while introducing steam to the FR during OCAC operation resulted in higher alkali emissions. It was concluded that steam likely enhances gas-phase K release through a reaction of K 2 CO 3 within the fuel char with steam to produce KOH(g). Solid sampling and analysis for K content was used along with SID measurements to develop a K mass balance for the reactor system. Mass balance results for the straw pellet fuel tests showed that LD slag OC absorbs approximately 15–51% of fuel K, 2.2% of fuel K is released to the gas phase, and up to 3.4% of fuel K is captured in the AR fly ash. The residual 40–80% of fuel K was determined to leave the FR as K-rich fly ash.

show abstract

“… 4 − 6 Straw biomass typically contains a high content of alkali metals and ash. 7 − 9 Serious ash slagging and agglomeration often occur in the furnace during combustion, and the pellet fuel of straw biomass further increases the agglomeration degree of ash. This is mainly due to the dense structure of pellet fuel, which contains low-melting-point compounds that polymerize easily at high temperatures.…”

Section: Introductionmentioning

confidence: 99%

Reduced Pollutant Emissions and Slagging Rate of Biomass Pellet Combustion by Optimizing the Multilayer Distribution of Secondary Air

Liu

Wang

et al. 2022

ACS Omega

View full text Add to dashboard Cite

The utilization of coal and other fossil fuels is becoming increasingly restricted. Biomass, as a clean and renewable energy, plays a significant role in achieving zero carbon emissions. However, biomass is prone to slagging in the combustion process due to its high alkali metal content. The ash slagging rate and pollutant emission level of flue gas can be reduced by optimizing the air distribution, in order to decrease the fuel layer temperature in the combustion chamber. The results reveal opposite change trends of CO and NO x concentrations in the flue gas. The NO x emissions of corn stalk combustion under the multilayer secondary air distribution are obvious compared with those of rice husk combustion. The slagging rate of corn stalks is highly correlated with temperature T 1 of the fuel bed. The silica ratio ( G ), alkali/acid ratio ( B / A ), Na content index (Na (index)), and alkaline index (Al c ) cannot accurately predict the slagging tendency when temperature T 1 changes. Therefore, the modified predictive index ( G t ) was proposed to predict the slagging tendency of corn stalks with the combustion zone temperature T 1 effectively. The experimental results can contribute to the efficient combustion and low pollutant emissions of biomass.

show abstract

Investigation of biomass alkali release in a dual circulating fluidized bed chemical looping combustion system

Cited by 52 publications

References 34 publications

Chemical Looping for Combustion of Solid Biomass: A Review

Chemical Looping for Combustion of Solid Biomass: A Review

Effects of Temperature, Operation Mode, and Steam Concentration on Alkali Release in Chemical Looping Conversion of Biomass─Experimental Investigation in a 10 kW_th Pilot

Reduced Pollutant Emissions and Slagging Rate of Biomass Pellet Combustion by Optimizing the Multilayer Distribution of Secondary Air

Contact Info

Product

Resources

About

Investigation of biomass alkali release in a dual circulating fluidized bed chemical looping combustion system

Cited by 52 publications

References 34 publications

Chemical Looping for Combustion of Solid Biomass: A Review

Chemical Looping for Combustion of Solid Biomass: A Review

Effects of Temperature, Operation Mode, and Steam Concentration on Alkali Release in Chemical Looping Conversion of Biomass─Experimental Investigation in a 10 kWth Pilot

Reduced Pollutant Emissions and Slagging Rate of Biomass Pellet Combustion by Optimizing the Multilayer Distribution of Secondary Air

Contact Info

Product

Resources

About

Effects of Temperature, Operation Mode, and Steam Concentration on Alkali Release in Chemical Looping Conversion of Biomass─Experimental Investigation in a 10 kW_th Pilot