二氧化碳和水气氛对高钠煤转化过程中钠迁移的影响
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摘要
对新疆的两种高钠煤(伊犁煤YL、呼图壁煤HTB)进行了N2、CO_2和H_2O气氛和不同温度下钠迁移的研究。采用逐级萃取和湿法消解法确定了原煤、半焦中钠的赋存形态,定量研究了两种煤中钠的挥发及迁移规律。结果表明,YL煤的形态钠中水溶钠占80.08%,HTB煤的形态钠中不溶钠占61.54%。不同气氛下,升高温度都可促进两种煤中钠的挥发,半焦中水溶钠比例减小,醋酸铵可溶钠比例会出现先增加后减少现象,盐酸可溶钠比例呈增加趋势。对于YL煤,CO_2气氛可抑制钠的挥发,H_2O蒸气可促进钠的挥发;900℃时,YL煤CO_2气氛下钠挥发仅为N2气氛下的50.25%,而H_2O气氛钠挥发为N2气氛下的111.45%。对于HTB煤,CO_2气氛也可抑制钠的挥发,900℃时CO_2气氛下钠挥发为N2气氛的80.91%;HTB煤在H_2O蒸气下,800℃之前钠挥发高于N2,当900℃时,钠挥发略低于N2气氛。YL煤形态钠中以水溶钠为主,其挥发的同时会向盐酸可溶钠及不溶钠转变。而HTB煤形态钠中以不溶钠为主,其次是水溶钠,CO_2和H_2O气氛能促进不溶钠向其他可溶态钠转变。
The sodium release and transformation of Yili( YL) and Hutubi( HTB) coal were examined at different temperatures under N2,CO_2 and H_2O atmospheres. By using sequential extraction and wet digestion separately,the occurrence mode and content of sodium in rawcoal and chars were measured. The migration of sodium in two coals was studied qualitatively and quantitatively. The results showthat water soluble sodium in YL coal accounts for 80.08%,while in HTB,insoluble sodium is 61.54%. The volatilization of sodium in two coals increases with increasing temperature. Water soluble sodium in semi coke shows a decrease trend;ammonium acetate soluble sodium increases and then decreases; hydrochloric acid soluble sodium exhibits an increasing tendency. For YL volatilization of sodium is inhibited by CO_2 while it is promoted by H_2O compared with N2. At 900 ℃ volatilization of sodium under CO_2 and H_2O is 50.25% and 111.45%,respectively,of that under N2. CO_2 atmosphere can inhibit volatilization of sodium in HTB. At 900 ℃ volatilized sodium under CO_2 is80.91% of that under N2. In H_2O atmosphere,volatilization of sodium is higher than that in N2 before 800 ℃ and slightly lower than that in N2 at 900 ℃. The predominant sodium in YL coal is water soluble which volatilized during increasing temperature and transformed to hydrochloric acid soluble and insoluble sodium simultaneously.While for HTB,insoluble sodium is the dominant occurrence mode,followed by water soluble one. CO_2 and H_2O can promote transformation of insoluble sodium to soluble one in HTB coal.
The sodium release and transformation of Yili( YL) and Hutubi( HTB) coal were examined at different temperatures under N2,CO_2 and H_2O atmospheres. By using sequential extraction and wet digestion separately,the occurrence mode and content of sodium in rawcoal and chars were measured. The migration of sodium in two coals was studied qualitatively and quantitatively. The results showthat water soluble sodium in YL coal accounts for 80.08%,while in HTB,insoluble sodium is 61.54%. The volatilization of sodium in two coals increases with increasing temperature. Water soluble sodium in semi coke shows a decrease trend;ammonium acetate soluble sodium increases and then decreases; hydrochloric acid soluble sodium exhibits an increasing tendency. For YL volatilization of sodium is inhibited by CO_2 while it is promoted by H_2O compared with N2. At 900 ℃ volatilization of sodium under CO_2 and H_2O is 50.25% and 111.45%,respectively,of that under N2. CO_2 atmosphere can inhibit volatilization of sodium in HTB. At 900 ℃ volatilized sodium under CO_2 is80.91% of that under N2. In H_2O atmosphere,volatilization of sodium is higher than that in N2 before 800 ℃ and slightly lower than that in N2 at 900 ℃. The predominant sodium in YL coal is water soluble which volatilized during increasing temperature and transformed to hydrochloric acid soluble and insoluble sodium simultaneously.While for HTB,insoluble sodium is the dominant occurrence mode,followed by water soluble one. CO_2 and H_2O can promote transformation of insoluble sodium to soluble one in HTB coal.
引文
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[11]刘大海,张守玉,涂圣康,金涛,施登宇,裴育峰.五彩湾煤中钠在热解过程中的形态变迁[J].燃料化学学报,2014,42(10):1190-1196.(LIU Da-hai,ZHANG Shou-yu,TU Sheng-kang,JIN Tao,SHI Deng-yu,PEI Yu-feng.Transformation of sodium during Wucaiwan coal pyrolysis[J].J Fuel Chem Technol,2014,42(10):1190-1196.)
[12]陈川,张守玉,刘大海,郭熙,董爱霞,熊绍武,施大钟,吕俊复.新疆高钠煤中钠的赋存形态及其对燃烧过程的影响[J].燃料化学学报,2013,41(7):832-838.(CHEN Chuan,ZHANG Shou-yu,LIU Da-hai,GUO Xi,DONG Ai-xia,XIONG Shao-wu,SHI Da-zhong,LJun-fu.Existence form of sodium in high sodium coals from Xinjiang and its effect on combustion process[J].J Fuel Chem Technol,2013,41(7):832-838.)
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[14]郭帅,蒋云峰,熊青安,宋双双,赵建涛,房倚天.准东煤热解过程中不同赋存形态钠变迁规律的研究[J].燃料化学学报,2017,45(3):257-264.(GUO Shuai,JIANG Yun-feng,XIONG Qing-an,SONG Shuang-shuang,ZHAO Jian-tao,FANG Yi-tian.Release and transformation behaviors of sodium species w ith different occurrence modes during pyrolysis of Zhundong coal[J].J Fuel Chem Technol,2017,45(3):257-264.)
[15]姚宇翔,金晶,钟程鹏,王永贞,高姗姗,赵庆庆.准东煤中钠的赋存形态及挥发特性[J].煤炭转化,2016,39(1):1-5.(YAO Yu-xiang,JIN Jing,ZHONG Cheng-peng,WANG Yong-chen,GAO Shan-shan,ZHAO Qing-qing.Occurrence mode and volatilization characteristic of sodium in Zhundong coal[J].Coal Convers,2016,39(1):1-5.)
[16]张军,汉春利,颜峥,余刚,刘坤磊,徐益谦.煤中钠在燃烧初期行为的研究[J].燃料化学学报,2001,29(1):49-53.(ZHANG Jun,HAN Chun-li,YAN Zheng,YU Gang,LIU Kun-lei,XU Yi-qian.Experimental studies on the behavior of sodium of coal in the initial stage of combustion[J].J Fuel Chem Technol,2001,29(1):49-53.)
[17]王文慧,贾宝玉,姚洪,李显.准东煤热解过程中钠的迁移规律研究[J].工程热物理学报,2015,36(12):2733-2737.(WANG Wen-hui,JIA Bao-yu,YAO Hong,LI Xia.An investigation of sodium transformation in Zhundong coal during pyrolysis[J].J Eng Thermophys-Rus,2015,36(12):2733-2737.)
[18]HE Y,QIU K Z,WHIDDON R,WANG Z H,ZHU Y Q,LIU Y Z,LI Z S,CEN K F.Release characteristic of different classes of sodium during combustion of Zhun-Dong coal investigated by laser-induced breakdow n spectroscopy[J].Sci Bull,2015,60(22):1927-1934.
[19]ZHANG L,JIAO F,BINNER E,BHATTACHARYA S,NINOMIYA Y,LI C Z.Experimental investigation of the combustion of bituminous coal in air and O2/CO2mixtures:2.Variation of the transformation behaviour of mineral matter w ith bulk gas composition[J].Fuel,2011,90(4):1361-1369.
[20]ENDERS M,WILLENBORG W,ALBRECHT J,PUTNIS A.Alkali retention in hot coal slag under controlled oxidizing gas atmospheres(air-CO2)[J].Fuel Process Technol,2000,68(1):57-73.
[21]KOSMINSKI A,ROSS D P,AGNEW J B.Transformations of sodium during gasification of low-rank coal[J].Fuel Process Technol,2006,87(11):943-952.
[22]SCHAFER H N S.Chapter 7-Functional groups and ion exchange properties[J].Sci Vict Brown Coal,1991:323-357.
[23]MCKEE D W,SPIRO C L,KOSKY P G,LAMBY E J.Catalysis of coal char gasification by alkali metal salts[J].Fuel,1983,62(2):217-220.
[24]LI X,HAYASHI J I,LI C Z.Volatilisation and catalytic effects of alkali and alkaline earth metallic species during the pyrolysis and gasification of Victorian brow n coal.Part VII.Raman spectroscopic study on the changes in char structure during the catalytic gasification in air[J].Fuel,2006,85(10):1509-1517.
[25]SATHE C,HAYASHI J I,LI C Z,CHIBA T.Release of alkali and alkaline earth metallic species during rapid pyrolysis of a Victorian brown coal at elevated pressures[J].Fuel,2003,82(12):1491-1497.
[26]MCKEE D W,SPIRO C L,KOSKY P G,LAMBY E J.Catalysis of coal char gasification by alkali metal salts[J].Fuel,1983,62(2):217-220.
[27]申文琴,熊利红,沙兴中.热煤气中碱金属蒸汽的形成及清除方法[J].煤气与热力,1998,18(6):3-5.(SHEN Wen-qin,XIONG Li-hong,SHA Xing-zhong.Formation and removal of gaseous alkali metal of hot gas[J].Gas Heat,1998,18(6):3-5.)
[28]胡天喜,于建国.Ca Cl2-Na Cl混合助剂分解钾长石提取钾的实验研究[J].过程工程学报,2010,10(4):701-705.(HU Tian-xi,YU Jian-guo.Experimental study on decomposition of K-feldspar with Ca Cl2and Na Cl for extraction of potassium[J].Chin J Process Eng,2010,10(4):701-705.)
[29]王玉江,余桂郁,邓敏,唐明述.含碱矿物碱性环境下分解的热力学分析[J].硅酸盐学报,2006,34(3):345-352.(WANG Yu-jiang,YU Gui-yu,DENG Min,TANG Ming-shu.Thermodynamic analysis of alkaline mineral dissolution in alkali solution[J].J Chin Ceramic Soc,2006,34(3):345-352.)
[30]WEI X F,HUANG J J,LIU T F,FANG Y T,WANG Y.Transformation of alkali metals during pyrolysis and gasification of a lignite[J].Energy Fuels,2008,22(3):1840-1844.
[2]WANG X B,XU Z X,WEI B,ZHANG L,TAN H Z,YANG T,MIKULˇC I'C H,DUI'C N.The ash deposition mechanism in boilers burning Zhundong coal w ith high contents of sodium and calcium:A study from ash evaporating to condensing[J].Appl Thermal Eng,2015,80:150-159.
[3]CHEN L,LI J H,GE M F.The poisoning effect of alkali metals doping over nano V2O5-WO3/Ti O2catalysts on selective catalytic reduction of NOxby NH3[J].Chem Eng J,2011,170(2):531-537.
[4]WANG C A,JIN X,WANG Y K,YAN Y,CUI J,LIU Y H,CHE D F.Release and transformation of sodium during pyrolysis of Zhundong coals[J].Energy Fuels,2015,29(1):78-85.
[5]SHIMOGORI M,MINE T,OHYATSU N,TAKARAYAMA N,MATSUMURA Y.Effects of fine ash particles and alkali metals on ash deposition characteristics at the initial stage of ash deposition determined in 1.5 M Wthpilot plant tests[J].Fuel,2012,97:233-240.
[6]宋维健,宋国良,齐晓宾,吕清刚.不同预处理方法对准东高碱煤中碱金属含量测定的影响[J].燃料化学学报,2016,44(2):162-167.(SONG Wei-jian,SONG Guo-liang,QI Xiao-bin,LQing-gang.Effect of pretreatment methods on the determination of alkali metal content in high alkali metal Zhundong coal[J].J Fuel Chem Technol,2016,44(2):162-167.)
[7]PETTERSSON A,ZEVENHOVEN M,STEENARI B M,MAND L E.Application of chemical fractionation methods for characterisation of biofuels,w aste derived fuels and CFB co-combustion fly ashes[J].Fuel,2008,87(15):3183-3193.
[8]JORDAN C A,AKAY G.Speciation and distribution of alkali,alkali earth metals and major ash forming elements during gasification of fuel cane bagasse[J].Fuel,2012,91(1):253-263.
[9]SPIRO C L,WONG J,LYTLE F W,GREEGOR R B,MAYLOTTE D H,LAMSON S H.Forms of potassium in coal and its combustion products[J].Fuel,1986,65(3):327-336.
[10]BENSON S A,HOLM P L.Comparison of inorganics in three low-rank coals[J].Ind Eng Chem Prod Res Dev,1985,24(1):145-149.
[11]刘大海,张守玉,涂圣康,金涛,施登宇,裴育峰.五彩湾煤中钠在热解过程中的形态变迁[J].燃料化学学报,2014,42(10):1190-1196.(LIU Da-hai,ZHANG Shou-yu,TU Sheng-kang,JIN Tao,SHI Deng-yu,PEI Yu-feng.Transformation of sodium during Wucaiwan coal pyrolysis[J].J Fuel Chem Technol,2014,42(10):1190-1196.)
[12]陈川,张守玉,刘大海,郭熙,董爱霞,熊绍武,施大钟,吕俊复.新疆高钠煤中钠的赋存形态及其对燃烧过程的影响[J].燃料化学学报,2013,41(7):832-838.(CHEN Chuan,ZHANG Shou-yu,LIU Da-hai,GUO Xi,DONG Ai-xia,XIONG Shao-wu,SHI Da-zhong,LJun-fu.Existence form of sodium in high sodium coals from Xinjiang and its effect on combustion process[J].J Fuel Chem Technol,2013,41(7):832-838.)
[13]徐彦辉.准东煤热解过程中无机钠的转化及对热解产物的影响[D].哈尔滨:哈尔滨工业大学,2015.(XU Yan-hui.The transformation of inorganic sodium and it’s effect on the products during the pyrolysis of zhundong coal[D].Harbin:Harbin Institute of Technology,2015.)
[14]郭帅,蒋云峰,熊青安,宋双双,赵建涛,房倚天.准东煤热解过程中不同赋存形态钠变迁规律的研究[J].燃料化学学报,2017,45(3):257-264.(GUO Shuai,JIANG Yun-feng,XIONG Qing-an,SONG Shuang-shuang,ZHAO Jian-tao,FANG Yi-tian.Release and transformation behaviors of sodium species w ith different occurrence modes during pyrolysis of Zhundong coal[J].J Fuel Chem Technol,2017,45(3):257-264.)
[15]姚宇翔,金晶,钟程鹏,王永贞,高姗姗,赵庆庆.准东煤中钠的赋存形态及挥发特性[J].煤炭转化,2016,39(1):1-5.(YAO Yu-xiang,JIN Jing,ZHONG Cheng-peng,WANG Yong-chen,GAO Shan-shan,ZHAO Qing-qing.Occurrence mode and volatilization characteristic of sodium in Zhundong coal[J].Coal Convers,2016,39(1):1-5.)
[16]张军,汉春利,颜峥,余刚,刘坤磊,徐益谦.煤中钠在燃烧初期行为的研究[J].燃料化学学报,2001,29(1):49-53.(ZHANG Jun,HAN Chun-li,YAN Zheng,YU Gang,LIU Kun-lei,XU Yi-qian.Experimental studies on the behavior of sodium of coal in the initial stage of combustion[J].J Fuel Chem Technol,2001,29(1):49-53.)
[17]王文慧,贾宝玉,姚洪,李显.准东煤热解过程中钠的迁移规律研究[J].工程热物理学报,2015,36(12):2733-2737.(WANG Wen-hui,JIA Bao-yu,YAO Hong,LI Xia.An investigation of sodium transformation in Zhundong coal during pyrolysis[J].J Eng Thermophys-Rus,2015,36(12):2733-2737.)
[18]HE Y,QIU K Z,WHIDDON R,WANG Z H,ZHU Y Q,LIU Y Z,LI Z S,CEN K F.Release characteristic of different classes of sodium during combustion of Zhun-Dong coal investigated by laser-induced breakdow n spectroscopy[J].Sci Bull,2015,60(22):1927-1934.
[19]ZHANG L,JIAO F,BINNER E,BHATTACHARYA S,NINOMIYA Y,LI C Z.Experimental investigation of the combustion of bituminous coal in air and O2/CO2mixtures:2.Variation of the transformation behaviour of mineral matter w ith bulk gas composition[J].Fuel,2011,90(4):1361-1369.
[20]ENDERS M,WILLENBORG W,ALBRECHT J,PUTNIS A.Alkali retention in hot coal slag under controlled oxidizing gas atmospheres(air-CO2)[J].Fuel Process Technol,2000,68(1):57-73.
[21]KOSMINSKI A,ROSS D P,AGNEW J B.Transformations of sodium during gasification of low-rank coal[J].Fuel Process Technol,2006,87(11):943-952.
[22]SCHAFER H N S.Chapter 7-Functional groups and ion exchange properties[J].Sci Vict Brown Coal,1991:323-357.
[23]MCKEE D W,SPIRO C L,KOSKY P G,LAMBY E J.Catalysis of coal char gasification by alkali metal salts[J].Fuel,1983,62(2):217-220.
[24]LI X,HAYASHI J I,LI C Z.Volatilisation and catalytic effects of alkali and alkaline earth metallic species during the pyrolysis and gasification of Victorian brow n coal.Part VII.Raman spectroscopic study on the changes in char structure during the catalytic gasification in air[J].Fuel,2006,85(10):1509-1517.
[25]SATHE C,HAYASHI J I,LI C Z,CHIBA T.Release of alkali and alkaline earth metallic species during rapid pyrolysis of a Victorian brown coal at elevated pressures[J].Fuel,2003,82(12):1491-1497.
[26]MCKEE D W,SPIRO C L,KOSKY P G,LAMBY E J.Catalysis of coal char gasification by alkali metal salts[J].Fuel,1983,62(2):217-220.
[27]申文琴,熊利红,沙兴中.热煤气中碱金属蒸汽的形成及清除方法[J].煤气与热力,1998,18(6):3-5.(SHEN Wen-qin,XIONG Li-hong,SHA Xing-zhong.Formation and removal of gaseous alkali metal of hot gas[J].Gas Heat,1998,18(6):3-5.)
[28]胡天喜,于建国.Ca Cl2-Na Cl混合助剂分解钾长石提取钾的实验研究[J].过程工程学报,2010,10(4):701-705.(HU Tian-xi,YU Jian-guo.Experimental study on decomposition of K-feldspar with Ca Cl2and Na Cl for extraction of potassium[J].Chin J Process Eng,2010,10(4):701-705.)
[29]王玉江,余桂郁,邓敏,唐明述.含碱矿物碱性环境下分解的热力学分析[J].硅酸盐学报,2006,34(3):345-352.(WANG Yu-jiang,YU Gui-yu,DENG Min,TANG Ming-shu.Thermodynamic analysis of alkaline mineral dissolution in alkali solution[J].J Chin Ceramic Soc,2006,34(3):345-352.)
[30]WEI X F,HUANG J J,LIU T F,FANG Y T,WANG Y.Transformation of alkali metals during pyrolysis and gasification of a lignite[J].Energy Fuels,2008,22(3):1840-1844.