摘要
为了深入研究炼焦煤成焦过程中形成的胶质体特性以及煤焦微观结构在热解过程中的演化规律,采用原态热解装置对古交焦煤、临汾肥煤与淮南1/3焦煤样品进行热解实验,制备胶质体原态半焦,并结合煤样的热重(TG)和吉氏流动度特性,对不同温度下的原态半焦进行拉曼光谱(Raman)、X射线衍射(XRD)、扫描电子显微镜(SEM)以及焦炭显微强度(MSI)表征,解析胶质体的软化-熔融-固化过程。结果表明:古交焦煤、临汾肥煤、淮南1/3焦煤煤样的最大热失重速率(K_(max))分别为0.30%/min、0.58%/min、0.84%/min,对应的温度点(T_(max))为482.2、462.3、431.2℃,均与胶质体熔融阶段重叠。随着热解温度(T)由初始软化温度(T_(s))升至固化温度(T_(r)),半焦的半峰宽(FWHM)增大,相对吸收强度(A_(G)/A_(all))增大,A_(D3)/A_(G)与A_(D1)/A_(G)均减小,A D4/A_(G)先减小后增大,表明半焦有序度增加、缺陷减少以及微晶结构单元逐渐完善。其中,温度由T_(s)至T_(r),古交焦煤、临汾肥煤、淮南1/3焦煤的A_(G)/A_(all)分别由16.38%增至17.21%、15.29%增至17.76%、14.75%增至17.01%;另外,FWHM由小到大的排序为古交焦煤、临汾肥煤、淮南1/3焦煤。随着T由T_(s)升至T_(r),半焦的芳香度(f_(a))、碳微晶堆叠厚度(L_(c))与微晶中碳平面尺寸(L_(a))等微晶结构参数均增大。温度由T_(s)~T_(r),古交焦煤、临汾肥煤、淮南1/3焦煤的L_(a)分别由2.87 nm增至3.47 nm、2.34 nm增至3.38 nm、2.40 nm增至3.36 nm;L_(c)分别由2.13 nm增至2.27 nm、2.04 nm增至2.24 nm、2.02 nm增至2.18 nm。随着T由T_(s)升至T_(r),半焦表面孔隙逐渐增多且孔径逐渐增大。选取淮南1/3JM煤样在401~950℃不同热解温度下热解,当T<T_(r)时,焦样MSI值接近于0;当T由474℃(T_(r))增加至950℃,焦样MSI值由10.20%增加至56.95%。
To investigate the characteristics thoroughly of the plastic mass developed during coking process of coking coal,and the changes of the microstructure of coal coke during the pyrolysis process,in-situ pyrolysis experiments were carried out on Gu jiao coking coal(JM),Lin fen rich coal(FM)and Huai Nan 1/3 coking coal(1/3JM)samples by in-situ pyrolysis equipment,and the colloid in situ semi-coke was prepared.Combined with the thermos gravimetric(TG)and Gieseler fluidity characteristics of coal samples,Raman spectroscopy(Raman),X-ray diffraction(XRD),scanning electron microscopy(SEM)and coke micro-strength index(MSI)were used to characterize in-situ semi-coke at different temperatures,and the softening-melt-curing process of the colloids was analyzed.The results showed that the maximum thermogravimetric rates(K_(max))of JM,FM and 1/3JM coal samples were 0.3%/min,0.58%/min and 0.84%/min,respectively.And the corresponding temperature points(T_(max))were 482.2,462.3 and 431.2℃,which overlapped with the melting stage of the plastic layer.As the pyrolysis temperature T increased from the initial softening temperature(T_(s))to the curing temperature(T_(r)),the semi-coke half-peak width(FWHM)increased,the relative absorption strength(A_(G)/A_(all))increased,A_(D3)/A_(G) decreased,A_(D1)/A_(G) decreased,and A D4/A_(G) decreased first and then increased.These showed that the order degree of semi-coke was increased,the defects were reduced,and the microcrystalline structure units were gradually improved.Among the T from T_(s) to T_(r),the A_(G)/A_(all) values of JM,FM and 1/3JM increased from 16.38%to 17.21%,15.29%to 17.76%and 14.75%to 17.01%,respectively.Also,for FWHM values,JM<FM<1/3JM.As T increased from T_(s) to T_(r),the crystallite structure parameters such as aromaticity(f_(a)),carbon crystallite stacking thickness(L_(c))and carbon plane size(L_(a))increased of semi-coke.From T_(s) to T_(r),the L_(a) of JM,FM and 1/3JM increased from 2.87 to 3.47 nm,2.34 to 3.38 nm and 2.40 to 3.36 nm,respectively.In addition,L_(c) increased from 2.13 to 2.27 nm,2.04 to 2.24 nm and 2.02 to 2.18 nm,respectively.With T increased from T_(s) to T_(r),the diameter of_(a)perture and pore size of the semi-coke surface increased gradually.1/3JM coal samples were pyrolyzed at different pyrolysis temperatures from 401℃to 950℃.When T was less than T_(r),the MSI value of coke samples was close to zero.When T increased from 474℃(T_(r))to 950℃,MSI value of coke sample increased from 10.20%to 56.95%.
作者
白效言
BAI Xiaoyan(China Coal Research Institute Corporation Ltd.,Beijing 100013,China;Beijing Key Laboratory of Coal Based Carbon Materials,Beijing 100013,China;CCTEG Low-carbon Technology Institute,Beijing 100013,China)
出处
《煤质技术》
2025年第4期1-10,共10页
Coal Quality Technology
基金
天地科技股份有限公司科技创新创业资金专项资助项目(2021-TD-QN001)。
关键词
胶质体
原态特性
炼焦煤
微晶结构
相对吸收强度
吉氏流动度
芳香度
堆叠厚度
plastic layer
in-situ characteristics
coking coal
crystallite structure
relative absorption strength
Gieseler fluidity
aromaticity
stacking thickness
