Effect of Ca2+ species with different modes of occurrence on direct liquefaction of a calcium-rich lignite

Li, Xiao; Bai, Zongqing; Bai, Jin; Zhao, Bian-Bian; Li, Pei; Yong, Han; Kong, Lingxue; Li, Wen

doi:10.1016/j.fuproc.2015.02.001

Cited by 21 publications

(10 citation statements)

References 28 publications

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“…The cation exchange treatment is in accordance with our previous study [20]. In brief, 200 mL of certain concentration of a metallic (Ca 2+ or Na + ) acetate solution was added to 20 g De-H and the mixtures were magnetically stirred at 60°C in a flask.…”

Section: Cation Exchange Treatmentmentioning

confidence: 99%

Influences of exchangeable metallic species on solvent extraction of Xiaolongtan lignite and characterization of the separated portions

Bai

et al. 2015

Fuel Processing Technology

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Section: Cation Exchange Treatmentmentioning

confidence: 99%

Influences of exchangeable metallic species on solvent extraction of Xiaolongtan lignite and characterization of the separated portions

Bai

et al. 2015

Fuel Processing Technology

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“…In addition, previous studies have found that when the AAEMs removal rate of eucalyptus is equal between hydrothermal pretreatment and hydrochloric acid leaching, the yield and composition distribution of bio-oil produced by rapid pyrolysis of the biomass treated by the two pretreatment methods are different. Moreover, the forms of AAEMs in biomass may affect the yield and composition distribution of bio-oil [ 23 ]. Therefore, it is of great significance to study the dissolution rule of AAEMs in different forms during pretreatment to control the yield and component distribution of bio-oil.…”

Section: Introductionmentioning

confidence: 99%

Optimization of Demineralization and Pyrolysis Performance of Eucalyptus Hydrothermal Pretreatment

Zhu

Bao

et al. 2022

Polymers

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The preparation of bio-oil through biomass pyrolysis is promoted by different demineralization processes to remove alkali and alkaline earth metal elements (AAEMs). In this study, the hydrothermal pretreatment demineralization was optimized by the response surface method. The pretreatment temperature, time and pH were the response elements, and the total dissolution rates of potassium, calcium and magnesium were the response values. The interactions of response factors for AAEMs removal were analyzed. The interaction between temperature and time was significant. The optimal AAEMs removal process was obtained with a reaction temperature of 172.98 °C, time of 59.77 min, and pH of 3.01. The optimal dissolution rate of AAEMs was 47.59%. The thermal stability of eucalyptus with and without pretreatment was analyzed by TGA. The hydrothermal pretreatment samples exhibit higher thermostability. The composition and distribution of pyrolysis products of different samples were analyzed by Py-GC/MS. The results showed that the content of sugars and high-quality bio-oil (C6, C7, C8 and C9) were 60.74% and 80.99%, respectively, by hydrothermal pretreatment. These results show that the removal of AAEMs through hydrothermal pretreatment not only improves the yield of bio-oil, but also improves the quality of bio-oil and promotes an upgrade in the quality of bio-oil.

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“…[15][16][17][18] Nevertheless, sodium species in sodium-rich coals show negative effects on the DCL process, mainly on oil yield. It has been well recognized that sodium species can lower oil yield in DCL, especially exchangeable sodium species (sodium species bound to coal matrix), [19][20][21] which has significantly restrained further utilization of sodium-rich coals in DCL technology. In order to mitigate the negative effects of sodium species and enhance oil yield in direct liquefaction of sodium-rich coals, adjusting occurrence modes of sodium species may be a feasible method, since previous work has proved that compared with exchangeable sodium species, water-soluble sodium species have less negative effects on oil yield in DCL.…”

Section: Introductionmentioning

confidence: 99%

Structural changes of Zhundong coal matrix induced by thermal treatment and its effects on oil yield in direct coal liquefaction

Han

2021

Intl J of Energy Research

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Sodium-rich coals are suitable raw materials for direct coal liquefaction (DCL).However, sodium species in coals, especially exchangeable ones, can significantly reduce oil yield. In this work, to increase oil yield in direct liquefaction of sodium-rich coals, a feasible method using organic solvents to pretreat sodium-rich coals is proposed. Initially, sodium-rich coal was thermally treated with tetralin or 1-methylnaphtalene. Then, raw coal and all the treated coals were liquefied under the same conditions to evaluate the effects of thermal treatment on structural changes of coal molecules and oil yield. The results show that surface areas of the treated coals increased to 7.86 m 2 /g at most, which was favorable for combination between hydrogen and coal molecules during the DCL process. More importantly, the content of hydrogen in the treated coals was 0.95 wt% higher than that of raw coal on average, suggesting that treated coals could be later liquefied at mild conditions. Raman spectra demonstrated that during thermal treatment with tetralin, small aromatic ring systems in raw coal were prehydrogenated and transformed into nonaromatic systems. The pre-hydrogenation of the coal matrix definitely contributes to the increase in oil yield. In view of sodium species distribution in the treated coals, it is proved that tetralin can promote the transformation of exchangeable sodium species into other chemical forms more easily than 1-methylnaphtalene, which implies that tetralin has more positive effects on the increase of oil yield. Compared with that of raw coal, oil yields in direct liquefaction of the samples treated by tetralin increase by 14.0 to 15.1 wt% (daf).

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Effect of Ca2+ species with different modes of occurrence on direct liquefaction of a calcium-rich lignite

Cited by 21 publications

References 28 publications

Influences of exchangeable metallic species on solvent extraction of Xiaolongtan lignite and characterization of the separated portions

Influences of exchangeable metallic species on solvent extraction of Xiaolongtan lignite and characterization of the separated portions

Optimization of Demineralization and Pyrolysis Performance of Eucalyptus Hydrothermal Pretreatment

Structural changes of Zhundong coal matrix induced by thermal treatment and its effects on oil yield in direct coal liquefaction

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