Effects of Na2CO3/K2CO3 on Chemical Looping Combustion Using Fe2O3/Al2O3 as Oxygen Carrier

Zhang, Zhifeng; Wang, Yifei; Zhu, Lingyan; Li, Jilin; Wang, Fuchen; Yu, Guangsuo

doi:10.1002/ceat.201900409

Cited by 14 publications

(4 citation statements)

References 31 publications

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“…A reasonable amount of KNO 3 is important for CLG, since less KNO 3 corresponds to the lower catalytic activity for the CLG reaction and more KNO 3 results in slagging on Fe 2 O 3 /Al 2 O 3 . 38 …”

Section: Resultsmentioning

confidence: 99%

CaO-Assisted Alkaline Liquid Waste Drives Corn Stalk Chemical Looping Gasification for Hydrogen Production

et al. 2020

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The chemical looping gasification (CLG) process is a promising pathway to produce hydrogen-enriched syngas with biomass. It is urgent to enhance the reactivity and thermal stability of oxygen carriers (OC) and capture the inherently separated CO 2 . This work presents the strategy of simultaneous modification of a Fe 2 O 3 /Al 2 O 3 oxygen carrier and the supplement of an oxidant for corn stalk chemical looping gasification by introducing KNO 3 -containing ethanol liquid waste. CaO is employed to capture the generated CO 2 and promote the reaction balance toward hydrogen production in a fuel reactor (FR). The highest carbon conversion reaction rate of 1.1 × 10 –4 mol/g could be obtained at the ratio of CaO to fuel carbon and the reaction temperature of 1.5 and 600 °C, respectively. The kinetics and thermodynamics analyses under the optimized condition are further discussed to verify the possibility and high efficiency of using alkaline organic liquid waste to boost solid fuel gasification for hydrogen production. This CLG strategy shows multifunctional merits, including organic liquid waste treatment, biomass CLG promotion, and hydrogen production enhancement.

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Section: Resultsmentioning

confidence: 99%

CaO-Assisted Alkaline Liquid Waste Drives Corn Stalk Chemical Looping Gasification for Hydrogen Production

et al. 2020

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“…[ 12 ] Al 2 O 3 has attracted attention as an support material that is inexpensive and readily available. [ 7,12,13 ] However, since iron oxide and alumina can form spinel structures at high temperatures, which limits the reduction of oxygen carriers, it is important to improve the reduction kinetics of oxygen carriers. [ 12,14 ] Some studies have reported the use of the self‐diffusion characteristics of alkali metals to improve the reduction kinetics of the OCs.…”

Section: Introductionmentioning

confidence: 99%

“…[ 12,14 ] Some studies have reported the use of the self‐diffusion characteristics of alkali metals to improve the reduction kinetics of the OCs. [ 7,13,15,16 ] However, alkali metals volatilize and deactivate at high temperatures, which prevents the oxygen carrier from being reused in multiple cycles and corrodes the reactor. [ 15,17,18 ]…”

Section: Introductionmentioning

confidence: 99%

Research of coal‐direct chemical looping hydrogen generation with iron‐based oxygen carrier modified by NaAlO₂

Zhang

et al. 2020

Can J Chem Eng

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This study reports a high-performance modified oxygen carrier (OC) in a three-cycle chemical looping process in which coal is used as the raw feedstock to produce hydrogen. A series of experiments of coal-direct chemical looping hydrogen generation (CLHG) were conducted in a batch fluidized bed reactor, in the absence or presence of the NaAlO 2. The experimental results indicated that the carbon conversion and hydrogen yield reached 87.0% and 1.30 L Á g −1 , respectively, when the coal/oxygen carrier (Fe4Al6) mass ratio was 1:20. However, FeO was the main product of the reduction process with Fe4Al6, which limits the production of hydrogen during steam oxidation. Therefore, NaAlO 2 was used to improve the reaction performance of the OC. The carbon conversion and hydrogen production of NaAlO 2-loaded oxygen carriers were 10.7% and 9.6% higher than Fe4Al6, respectively. X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET), and temperatureprogrammed reduction (TPR) techniques were used to characterize the oxygen carriers. According to the XRD analysis results, the addition of 5 wt% NaAlO 2 can generate NaFeO 2. The unique layer structure of NaFeO 2 can loosen the structure between Fe 2 O 3 and Al 2 O 3. Thus, the surface morphology and pore structure of the oxygen carrier were improved, which are responsible for the enhancement in reactivity rather than the catalytic effects of the alkali metal. The cycle performance of the Na0.5Fe4Al6 remained stable after multi-redox cycles, and no serious sintering phenomena were observed; in addition, the carbon conversion and hydrogen yield remained above 86% and 1.40 L Á g −1 , respectively. K E Y W O R D S chemical looping, crystal structure, Fe 2 O 3 /Al 2 O 3 , H 2 production, sodium modification 1 | INTRODUCTION Currently there is growing interest in using hydrogen as a clean energy carrier since it can provide a high Jinshuai Li and Xiuli Zhang contributed equally to this work.

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“…Oxygen carriers mentioned above need large amount of energy as high reaction temperature. Researchers provided that flue gas of high temperature can be used as heat resource for oxygen carriers in CLAS system . However, the problem of depleted energy for CLAS technology hasn't been solved fundamentally as the waste heat of high temperature has been used effectively.…”

Section: Introductionmentioning

confidence: 99%

Practicability study of YBaCo₄O_7+δ and substituted samples for chemical looping air separation process

Hou

Wang

et al. 2018

Env Prog and Sustain Energy

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Chemical looping air separation, producing oxygen, is a non‐traditional and energy efficient process. Oxygen carrier is core of the process. In the article, practicability of YBaCo4O7+δ and substituted samples reacting at temperature lower than 500°C as oxygen carriers are studied for a chemical looping air separation process. First, the XRD analysis of synthesized samples was performed to discern the formation of 114 phase structure. The TG results obtained by temperature‐programmed thermogravimetry show that YBaCo4O7+δ and substituted samples have high oxygen storage capacity. The DTG results obtained by isothermal and temperature‐programmed thermogravimetry show that YBaCo4O7+δ and substituted samples have a faster oxygen desorption rate and a slower oxygen absorption rate. The isothermal TG results show that the conversion time decreases, and the amount of oxygen absorption/desorption first increases and then decreases, with increasing the operating temperature of oxygen absorption. With increasing the operating temperature of oxygen desorption, the conversion time decreases. The optimal temperature of oxygen absorption and desorption is 330 and 450°C, respectively. Oxygen absorption and desorption processes occur in a highly reversible manner. © 2018 American Institute of Chemical Engineers Environ Prog, 38: 563–569, 2019

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Effects of Na₂CO₃/K₂CO₃ on Chemical Looping Combustion Using Fe₂O₃/Al₂O₃ as Oxygen Carrier

Cited by 14 publications

References 31 publications

CaO-Assisted Alkaline Liquid Waste Drives Corn Stalk Chemical Looping Gasification for Hydrogen Production

CaO-Assisted Alkaline Liquid Waste Drives Corn Stalk Chemical Looping Gasification for Hydrogen Production

Research of coal‐direct chemical looping hydrogen generation with iron‐based oxygen carrier modified by NaAlO₂

Practicability study of YBaCo₄O_7+δ and substituted samples for chemical looping air separation process

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Effects of Na2CO3/K2CO3 on Chemical Looping Combustion Using Fe2O3/Al2O3 as Oxygen Carrier

Cited by 14 publications

References 31 publications

CaO-Assisted Alkaline Liquid Waste Drives Corn Stalk Chemical Looping Gasification for Hydrogen Production

CaO-Assisted Alkaline Liquid Waste Drives Corn Stalk Chemical Looping Gasification for Hydrogen Production

Research of coal‐direct chemical looping hydrogen generation with iron‐based oxygen carrier modified by NaAlO2

Practicability study of YBaCo4O7+δ and substituted samples for chemical looping air separation process

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Effects of Na₂CO₃/K₂CO₃ on Chemical Looping Combustion Using Fe₂O₃/Al₂O₃ as Oxygen Carrier

Research of coal‐direct chemical looping hydrogen generation with iron‐based oxygen carrier modified by NaAlO₂

Practicability study of YBaCo₄O_7+δ and substituted samples for chemical looping air separation process