Pan GAO , Xing-qi HUANG , Yu-tong LIU , Aikeremu ABULAITI , Shao-xia YANG
{"title":"铁酸钙为氧载体的生物炭化学环气化动力学分析","authors":"Pan GAO , Xing-qi HUANG , Yu-tong LIU , Aikeremu ABULAITI , Shao-xia YANG","doi":"10.1016/S1872-5813(23)60356-1","DOIUrl":null,"url":null,"abstract":"<div><p>The chemical looping gasification (CLG) kinetics of biochars with calcium ferrite as oxygen carriers and the effects of different kinds of calcium ferrite and biochars were investigated by TGA. The properties of biochars and calcium ferrite were analyzed by XRD, SEM, BET, etc. The Škvára-Šesták method was used to determine the kinetic mechanism function. The results show that the reduction reaction rate and the oxygen carrying capacity of oxygen carriers follow the sequence: Ca<sub>2</sub>Fe<sub>2</sub>O<sub>5</sub> > CaFe<sub>2</sub>O<sub>4</sub> > Fe<sub>2</sub>O<sub>3</sub>, and CaFe<sub>2</sub>O<sub>4</sub> > Ca<sub>2</sub>Fe<sub>2</sub>O<sub>5</sub> > Fe<sub>2</sub>O<sub>3</sub>, respectively. The oxygen carriers can be completely reduced to Fe and CaO by biochar. The activation energy of CaFe<sub>2</sub>O<sub>4</sub> reduction is in the range of 167.44–600.83 kJ/mol; and the activation energy of Ca<sub>2</sub>Fe<sub>2</sub>O<sub>5</sub> reduction is in the range of 413.62–583.51 kJ/mol. The CaFe<sub>3</sub>O<sub>5</sub> generated during the reduction of CaFe<sub>2</sub>O<sub>4</sub> may have a negative influence on the lattice oxygen diffusion. The reduction of CaFe<sub>2</sub>O<sub>4</sub> can be divided into two stages: when the conversion degree α is less than 0.15, the CaFe<sub>2</sub>O<sub>4</sub> is reduced to Ca<sub>2</sub>Fe<sub>2</sub>O<sub>5</sub> following the random nucleation and nuclei growth model; when α is greater than 0.15, Ca<sub>2</sub>Fe<sub>2</sub>O<sub>5</sub> is further reduced to CaO and Fe following the 3-D diffusion mechanism. The mechanism function of the reduction of Ca<sub>2</sub>Fe<sub>2</sub>O<sub>5</sub> is the same as that of the second stage of CaFe<sub>2</sub>O<sub>4</sub> reduction.</p></div>","PeriodicalId":15956,"journal":{"name":"燃料化学学报","volume":"51 9","pages":"Pages 1259-1272"},"PeriodicalIF":0.0000,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Kinetic analysis of biochar chemical looping gasification with calcium ferrite as oxygen carriers\",\"authors\":\"Pan GAO , Xing-qi HUANG , Yu-tong LIU , Aikeremu ABULAITI , Shao-xia YANG\",\"doi\":\"10.1016/S1872-5813(23)60356-1\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>The chemical looping gasification (CLG) kinetics of biochars with calcium ferrite as oxygen carriers and the effects of different kinds of calcium ferrite and biochars were investigated by TGA. The properties of biochars and calcium ferrite were analyzed by XRD, SEM, BET, etc. The Škvára-Šesták method was used to determine the kinetic mechanism function. The results show that the reduction reaction rate and the oxygen carrying capacity of oxygen carriers follow the sequence: Ca<sub>2</sub>Fe<sub>2</sub>O<sub>5</sub> > CaFe<sub>2</sub>O<sub>4</sub> > Fe<sub>2</sub>O<sub>3</sub>, and CaFe<sub>2</sub>O<sub>4</sub> > Ca<sub>2</sub>Fe<sub>2</sub>O<sub>5</sub> > Fe<sub>2</sub>O<sub>3</sub>, respectively. The oxygen carriers can be completely reduced to Fe and CaO by biochar. The activation energy of CaFe<sub>2</sub>O<sub>4</sub> reduction is in the range of 167.44–600.83 kJ/mol; and the activation energy of Ca<sub>2</sub>Fe<sub>2</sub>O<sub>5</sub> reduction is in the range of 413.62–583.51 kJ/mol. The CaFe<sub>3</sub>O<sub>5</sub> generated during the reduction of CaFe<sub>2</sub>O<sub>4</sub> may have a negative influence on the lattice oxygen diffusion. The reduction of CaFe<sub>2</sub>O<sub>4</sub> can be divided into two stages: when the conversion degree α is less than 0.15, the CaFe<sub>2</sub>O<sub>4</sub> is reduced to Ca<sub>2</sub>Fe<sub>2</sub>O<sub>5</sub> following the random nucleation and nuclei growth model; when α is greater than 0.15, Ca<sub>2</sub>Fe<sub>2</sub>O<sub>5</sub> is further reduced to CaO and Fe following the 3-D diffusion mechanism. The mechanism function of the reduction of Ca<sub>2</sub>Fe<sub>2</sub>O<sub>5</sub> is the same as that of the second stage of CaFe<sub>2</sub>O<sub>4</sub> reduction.</p></div>\",\"PeriodicalId\":15956,\"journal\":{\"name\":\"燃料化学学报\",\"volume\":\"51 9\",\"pages\":\"Pages 1259-1272\"},\"PeriodicalIF\":0.0000,\"publicationDate\":\"2023-09-01\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"燃料化学学报\",\"FirstCategoryId\":\"1087\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S1872581323603561\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q3\",\"JCRName\":\"Energy\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"燃料化学学报","FirstCategoryId":"1087","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S1872581323603561","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"Energy","Score":null,"Total":0}
Kinetic analysis of biochar chemical looping gasification with calcium ferrite as oxygen carriers
The chemical looping gasification (CLG) kinetics of biochars with calcium ferrite as oxygen carriers and the effects of different kinds of calcium ferrite and biochars were investigated by TGA. The properties of biochars and calcium ferrite were analyzed by XRD, SEM, BET, etc. The Škvára-Šesták method was used to determine the kinetic mechanism function. The results show that the reduction reaction rate and the oxygen carrying capacity of oxygen carriers follow the sequence: Ca2Fe2O5 > CaFe2O4 > Fe2O3, and CaFe2O4 > Ca2Fe2O5 > Fe2O3, respectively. The oxygen carriers can be completely reduced to Fe and CaO by biochar. The activation energy of CaFe2O4 reduction is in the range of 167.44–600.83 kJ/mol; and the activation energy of Ca2Fe2O5 reduction is in the range of 413.62–583.51 kJ/mol. The CaFe3O5 generated during the reduction of CaFe2O4 may have a negative influence on the lattice oxygen diffusion. The reduction of CaFe2O4 can be divided into two stages: when the conversion degree α is less than 0.15, the CaFe2O4 is reduced to Ca2Fe2O5 following the random nucleation and nuclei growth model; when α is greater than 0.15, Ca2Fe2O5 is further reduced to CaO and Fe following the 3-D diffusion mechanism. The mechanism function of the reduction of Ca2Fe2O5 is the same as that of the second stage of CaFe2O4 reduction.
期刊介绍：
Journal of Fuel Chemistry and Technology (Ranliao Huaxue Xuebao) is a Chinese Academy of Sciences(CAS) journal started in 1956, sponsored by the Chinese Chemical Society and the Institute of Coal Chemistry, Chinese Academy of Sciences(CAS). The journal is published bimonthly by Science Press in China and widely distributed in about 20 countries. Journal of Fuel Chemistry and Technology publishes reports of both basic and applied research in the chemistry and chemical engineering of many energy sources, including that involved in the nature, processing and utilization of coal, petroleum, oil shale, natural gas, biomass and synfuels, as well as related subjects of increasing interest such as C1 chemistry, pollutions control and new catalytic materials. Types of publications include original research articles, short communications, research notes and reviews. Both domestic and international contributors are welcome. Manuscripts written in Chinese or English will be accepted. Additional English titles, abstracts and key words should be included in Chinese manuscripts. All manuscripts are subject to critical review by the editorial committee, which is composed of about 10 foreign and 50 Chinese experts in fuel science. Journal of Fuel Chemistry and Technology has been a source of primary research work in fuel chemistry as a Chinese core scientific periodical.
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