CO2-gasification kinetics of biomass char with a red mud oxygen carrier for chemical looping combustion

Xu, Jianzheng; Song, Tao

doi:10.1016/j.fuel.2021.123011

Cited by 19 publications

(8 citation statements)

References 32 publications

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“…Guo et al 12 studied the kinetics of gasification of three coal chars toward iron-based oxygen carriers at pressures between 0.1 and 1.2 MPa. Xu and Song 13 used rice husk char and red mud oxygen carrier, a solid waste from an alumina-roasting process, in a CO 2 gasification. Despite these, none of the previous studies has reported the kinetics of char conversion toward pre-reduced oxygen carriers, while this is highly applicable for CLG.…”

Section: Introductionmentioning

confidence: 99%

Effect of the Mass Conversion Degree of an Oxygen Carrier on Char Conversion and Its Implication for Chemical Looping Gasification

et al. 2022

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Chemical looping gasification (CLG) is an emerging process that aims to produce valuable chemical feedstocks. The key operational requirement of CLG is to limit the oxygen transfer from the air reactor (AR) to the fuel reactor (FR). This can be accomplished by partially oxidizing the oxygen carrier in the AR, which may lead to a higher reduction degree of the oxygen carrier under the fuel conversion. A highly reduced oxygen carrier may experience multiple issues, such as agglomeration and defluidization. Given such an interest, this study examined how the variation of the mass conversion degree of ilmenite may affect the conversion of pine forest residue char in a fluidized bed batch reactor. Ilmenite was pre-reduced using diluted CO and then underwent the char conversion at 850, 900, 950, and 975 °C. Our investigations showed that the activation energy of the char conversion was between 194 and 256 kJ/mol, depending upon the mass conversion degree of ilmenite. Furthermore, the hydrogen partial pressure in the particle bed increased as the oxygen carrier mass conversion degree decreased, which was accompanied by a lower reaction rate and a higher reduction potential. Such a hydrogen inhibition effect was confirmed in the experiments; therefore, the change in the mass conversion degree indirectly affected the char conversion. Langmuir–Hinshelwood mechanism models used to evaluate the char conversion were validated. On the basis of the physical observation and characterizations, the use of ilmenite in CLG with biomass char as fuel will likely not suffer from major agglomeration or fluidization issues.

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Section: Introductionmentioning

confidence: 99%

Effect of the Mass Conversion Degree of an Oxygen Carrier on Char Conversion and Its Implication for Chemical Looping Gasification

et al. 2022

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“…Red mud from the Bayer process, from LuBei Chemical Industry Co. Ltd., China, was used as the oxygen carrier with its properties tested in our previous work. ,, As shown in Table , the X-ray fluorescence (XRF) test suggests that the red mud has a high content of SiO 2 and Al 2 O 3 but a relatively low content of CaO. The original red mud was calcined in a muffle oven at 950 °C for 3 h and then sieved to a particle size of 0.3–0.45 mm.…”

Section: Methodsmentioning

confidence: 99%

“…Red mud, as a solid waste of the Al industry, is rich in iron and contains some cementitious materials such as CaO, Al 2 O 3 , and SiO 2 . Because it contributes 40–80 wt % Fe 2 O 3 to the red mud, it has become a potential oxygen carrier for CLC processes. − …”

Section: Introductionmentioning

confidence: 99%

Sulfur Evolution and Capture Behavior by a Solid Waste of Red Mud during Chemical Looping Combustion of Petroleum Coke

Zhang

Liu

et al. 2022

Energy Fuels

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The sulfur evolution behavior during the chemical looping combustion (CLC) process of petroleum coke was investigated in a fluidized bed reactor with a low-cost solid waste of red mud as the oxygen carrier. Effects of temperature, oxygen carrier, and potassium catalyst addition on sulfur release were investigated, and H 2 S oxidization kinetics with the red mud and the effect of elements in the red mud on sulfur conversion were evaluated in detail. The red mud oxygen carrier had a promoting effect on H 2 S generation and thus enhanced sulfur conversion. The addition of potassium remarkably accelerated carbon conversion due to its catalytic effect. Meanwhile, it promoted H 2 generation and then enhanced the generation of H 2 S. The addition of potassium into the process could weaken the release of gaseous sulfur but had no obvious negative influence on the reactivity of the red mud oxygen carrier. The experiment H 2 S interaction with the red mud suggested that the conversion of H 2 S to SO 2 decreased with increasing temperature. The red mud has a low ability to oxidize H 2 S to SO 2 but a high reactivity to capture sulfur-containing gases. Solid sulfur-containing products such as CaSO 4 and Fe 3 S 4 as well as K 2 S 2 in the case of K addition into the process were detected.

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“…13−16 Red mud from the Bayer process, one of the general methods for alumina production, usually contains 30−60 wt % Fe 2 O 3 , depending on the grade of bauxite. 17,18 Chen et al 19 investigated the reaction performance of red mud during the CLC process and found that the red mud oxygen carrier had higher reactivity than the synthesized one, whereas some red mud had low activity due to its special structure and components. Deng et al 20 combined two kinds of red muds with regard to modify the structure and distribution of active components for CLC application and found that the synergy effect of the active and inert components improved the reactivity and stability of oxygen carriers.…”

Section: Introductionmentioning

confidence: 99%

“…Red mud is a solid waste from the alumina production industry. − It is estimated that 0.7–2.0 tons of red mud would be produced by the production of 1 ton of alumina . The main chemical components in red mud are Fe 2 O 3 , Al 2 O 3 , SiO 2 , TiO 2 , Na 2 O, and CaO, while Fe 2 O 3 is the active component for CLC applications. − Red mud from the Bayer process, one of the general methods for alumina production, usually contains 30–60 wt % Fe 2 O 3 , depending on the grade of bauxite. , Chen et al investigated the reaction performance of red mud during the CLC process and found that the red mud oxygen carrier had higher reactivity than the synthesized one, whereas some red mud had low activity due to its special structure and components. Deng et al combined two kinds of red muds with regard to modify the structure and distribution of active components for CLC application and found that the synergy effect of the active and inert components improved the reactivity and stability of oxygen carriers.…”

Section: Introductionmentioning

confidence: 99%

Reactivity and Stability of Different Red Muds as Oxygen Carriers for Chemical Looping Combustion of Methane and Biomass in a Fluidized Bed

et al. 2022

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The reactivity and stability of two low-cost red muds (LuShan and XinFa) as oxygen carriers for chemical looping combustion (CLC) were experimentally investigated in a fluidized bed, with methane and biomass char, respectively. CH 4 conversions using the present red muds were quite low, <20% after stable cycles. The XinFa red mud had better reactivity and stability in comparison with the LuShan red mud, with its CO 2 selectivity maintained at about 80% during 50 cycles. Due to the high content of Ca in the LuShan red mud, its promoting effect on the water−gas shift reaction led to continuous high H 2 production during biomass char-fueled experiments. The XinFa red mud achieved a complete conversion of char with only CO 2 as the gaseous product. Further, it showed better resistance to attrition. The agglomeration affinity in the case of using biomass char as fuel was stronger than that when using methane as fuel. NaAlSiO 4 with a high melting point was detected in both fresh and cycled oxygen carriers. Ca 2 Al 2 SiO 7 was found in the LuShan red mud due to the interactions among Ca, Al, and Si at elevated temperatures.

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CO2-gasification kinetics of biomass char with a red mud oxygen carrier for chemical looping combustion

Cited by 19 publications

References 32 publications

Effect of the Mass Conversion Degree of an Oxygen Carrier on Char Conversion and Its Implication for Chemical Looping Gasification

Effect of the Mass Conversion Degree of an Oxygen Carrier on Char Conversion and Its Implication for Chemical Looping Gasification

Sulfur Evolution and Capture Behavior by a Solid Waste of Red Mud during Chemical Looping Combustion of Petroleum Coke

Reactivity and Stability of Different Red Muds as Oxygen Carriers for Chemical Looping Combustion of Methane and Biomass in a Fluidized Bed

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