Effects of potassium and CO atmosphere on properties of biomass chars from flash pyrolysis
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摘要: 利用固定床反应器、红外光谱仪、吸附仪、X射线衍射仪、电感耦合等离子原子发射光谱仪、偏光显微镜等对比研究了原生生物质(原生物质)及水洗脱钾生物质(脱钾生物质)在N2及富一氧化碳(CO)气氛下所得半焦的产率、官能团及其他物化结构的变化规律。研究表明,与脱钾生物质相比,热解温度低于750℃时,原生物质的半焦产率降低、比表面积增大、芳环结构减少而烷基、脂肪族结构等增加;与N2相比,富CO气氛下所得半焦产率降低、比表面积增大,芳香结构、脂肪族结构、烷基减小。而热解温度高于750℃时,生物质中的钾和热解气氛中的CO均使生物质半焦产率增加、官能团数量和比表面积减少。利用偏光显微镜对生物质半焦表面矿物质的研究表明,热解温度低于750℃时,所得半焦表面矿物组分较少且高度分散;热解温度高于750℃时,所得半焦表面矿物组分较多,分布密集且熔融团聚现象随温度升高而增多。而对于半焦石墨化程度的研究表明,半焦石墨化程度随温度升高而增加,但低热解温度所得半焦的石墨化程度较差。温度高于750℃时,CO气氛使石墨化程度增加,而钾使石墨化程度降低。Abstract: Raw biomass and its de-potassium sample washed by water were pyrolyzed in a fixed bed reactor under pure N2 and CO-rich atmosphere at different temperatures. The obtained biomass chars were characterized by Fourier transform infrared spectroscopy (FT-IR), surface area analyzer, inductively coupled plasma emission spectroscopy and polarizing microscope. The yields of char, functional groups and other physicochemical structure were also studied and their evolution behaviors were examined. The results show that below 750 ℃, the BET surface areas and the amounts of alkyl and aliphatic functional groups in the chars derived from raw biomass are higher than those of de-potassium ones, but the char yields and the amounts of aromatic functional groups in the chars of raw biomass are lower than that of de-potassium samples. As to the effect of CO atmosphere, the yields of char and the amounts of all functional group in the chars derived from CO-rich atmosphere are less than that of N2 atmosphere, But the surface areas is higher than that of N2 atmosphere. Above 750 ℃, both potassium and CO can help to increase the char yields but decrease the amount of functional group and BET surface areas. In addition, the minerals are highly scattered and theirs amount on the surface of chars (raw biomass char, N2 atmosphere) is less when the pyrolysis temperature is lower than 750 ℃; while above 750 ℃, those are higher and the clusters of fusion mineral components increases with increasing pyrolysis temperature. As for the graphitization degree of biomass chars, it increases with increasing pyrolysis temperature but poor graphitization was obtained when the pyrolysis temperature is lower than 750 ℃. Moreover, CO can help to increase while K decreases the graphitization degree above 750 ℃.
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Key words:
- biomass char /
- potassium /
- pyrolysis atmosphere
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表 1 松木屑的工业分析和元素分析
Table 1 Proximate and ultimate analyses of biomass
表 2 松木屑灰成分分析
Table 2 Ash composition of biomass
表 3 不同半焦的比表面积
Table 3 BET surface area of different chars
表 4 富CO气氛下原生物质950 ℃热解半焦晶体结构参数
Table 4 Crystal structure parameters of R-biomass 950 ℃char under CO:N2=1:1 atmosphere
表 5 不同热解半焦的部分晶体结构参数
Table 5 Part of crystal structure parameters of different chars
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[1] 郭海霞, 左月明, 张虎.生物质能利用技术的研究进展[J].农机化研究, 2011, 33(6):178-185. http://www.cnki.com.cn/Article/CJFDTOTAL-NJYJ201106048.htmGUO Hai-xia, ZUO Ming-yue, ZHANG Hu. Progress in biomass energy utilization[J]. J Agric Mech Res, 2011, 33(6):178-185. http://www.cnki.com.cn/Article/CJFDTOTAL-NJYJ201106048.htm [2] 万仁新.生物质能工程[M].北京:中国农业出版社, 1995.WAN Ren-xin. Biomass Energy Engineering[M]. Beijing:China Agriculture Press, 1995. [3] 谭洪, 王树荣, 骆仲泱, 余春江, 岑可法.金属盐对生物质热解特性影响试验研究[J].工程热物理学报, 2005, 26(5):742-744. http://cdmd.cnki.com.cn/Article/CDMD-10487-2008022462.htmTAN Hong, WANG Shu-rong, LUO Zhong-yang, YU Chun-jiang, CEN Ke-fa. Influence of metallic salt on biomass flash pyrolysis characteristics[J]. J Eng Thermophys, 2005, 26(5):742-744. http://cdmd.cnki.com.cn/Article/CDMD-10487-2008022462.htm [4] 高松平, 赵建涛, 王志青, 王建飞, 房倚天, 黄戒介. CO对褐煤快速热解行为的影响[J].燃料化学学报, 2013, 41(5):550-557. http://rlhxxb.sxicc.ac.cn/CN/abstract/abstract18178.shtmlGAO Song-ping, ZHAO Jian-tao, WANG Zhi-qing, WANG Jian-fei, FANG Yi-tian, HUANG Jie-jie. Effect of CO on fast pyrolysis behaviors of lignite[J]. J Fuel Chem Technol, 2013, 41(5):550-557. http://rlhxxb.sxicc.ac.cn/CN/abstract/abstract18178.shtml [5] ZOLIN A, JENSEN A, JENSEN P A, FRANDSEN F, DAM-JOHANSEN K. The influence of inorganic materials on the thermal deactivation of fuel chars[J]. Energy Fuels, 2001, 15(5):1110-1122. doi: 10.1021/ef000288d [6] MOURANT D, WANG Z, HE M, WANG X S, GARCIA-PEREZ M, LING K, LI C Z. Mallee wood fast pyrolysis:Effects of alkali and alkaline earth metallic species on the yield and composition of bio-oil[J]. Fuel, 2011, 90(9):2915-2922. doi: 10.1016/j.fuel.2011.04.033 [7] OKUNO T, SONOYAMA N, HAYASHI J I, LI C Z, SATHE C, CHIBA T. Primary release of alkali and alkaline earth metallic species during the pyrolysis of pulverized biomass[J]. Energy Fuels, 2005, 19(5):2164-2171. doi: 10.1021/ef050002a [8] LIU H, FENG Y, WU S, LIU D. The role of ash particles in the bed agglomeration during the fluidized bed combustion of rice straw[J]. Bioresour Technol, 2009, 100(24):6505-6513. doi: 10.1016/j.biortech.2009.06.098 [9] 王贤华, 陈汉平, 王静, 辛芬, 杨海平.无机矿物盐对生物质热解特性的影响[J].燃料化学学报, 2008, 36(6):679-683. http://rlhxxb.sxicc.ac.cn/CN/abstract/abstract17316.shtmlWANG Xian-hua, CHEN Han-ping, WANG Jing, XIN Fen, YANG Hai-ping. Influence of mineral matters on biomass pyrolysis characteristic[J]. J Fuel Chem Technol, 2008, 36(6):679-683. http://rlhxxb.sxicc.ac.cn/CN/abstract/abstract17316.shtml [10] 杨海平, 陈汉平, 杜胜磊, 陈应泉, 王贤华, 张世红.碱金属盐对生物质三组分热解的影响[J].中国电机工学报, 2009, 29(17):70-75. http://www.cnki.com.cn/Article/CJFDTOTAL-ZGDC200917014.htmYANG Hai-ping, CHEN Han-ping, DU Sheng-lei, CHEN Ying-quan, WANG Xian-hua, ZHANG Shi-hong. Influence of alkali salts on the pyrolysis of biomass three components[J]. Proc CSEE, 2009, 29(17):70-75. http://www.cnki.com.cn/Article/CJFDTOTAL-ZGDC200917014.htm [11] 张二霞. 富氢气氛下煤催化热解特性研究[D]. 内蒙古: 内蒙古工业大学, 2016.ZHANG Er-xia. Hydrogen pyrolysis performance and its char's microcosmic structure of doped Shengli lignite[D]. Inner Mongolia:Inner Mongolia University of Technology, 2016. [12] 吴道洪. 煤加氢热解气化耦合方法: 中国, 102061182A[P]. 2011-05-18A. 2011-05-18. WU Dao-hong. Coal hydrogenation pyrolysis and gasification coupling method:CN, 102061182A[P]. 2011-05-18. [13] 王勤辉, 方梦祥, 骆仲泱, 施正伦, 程乐鸣, 余春江. 基于流化床热解技术的煤气焦油半焦蒸汽多联产方法: 中国, 102585913A[P]. 2012-07-18.A. 2012-07-18. WANG Qin-hui, FANG Meng-xiang, LUO Zhong-yang, SHI Zheng-lun, CHENG Le-ming, YU Chun-jiang. Method of multi-production of gas-tar semi-coke steam based on fluidized bed pyrolysis technology:CN, 102585913A[P]. 2012-07-18. [14] ARRIVNAA A, 李保庆, 李文, PUREVSUREN B, MUNKHJARGAL Sh, 刘粉荣, 白宗庆, 王刚.煤在合成气、氢气和氮气气氛下的热解研究[J].燃料化学学报, 1998, 26(1):13-17. http://rlhxxb.sxicc.ac.cn/CN/abstract/abstract17094.shtmlARRIUNAA A, LI Bao-ing, LI Wen, PURENSUREN B, MUNKHJARGAL Sh, LIU Fen-rong, BAI Zong-qing, WANG Gang. Coal pyrolysis under synthesis gas, hydrogen and nitrogen[J]. J Fuel Chem Technol, 2007, 35(1):1-4. http://rlhxxb.sxicc.ac.cn/CN/abstract/abstract17094.shtml [15] 廖洪强, 李保庆, 张碧江.煤-焦炉气共热解特性研究[J].燃料化学学报, 1998, 26(1):13-17. http://www.cnki.com.cn/Article/CJFDTOTAL-RLHX903.009.htmLIAO Hong-qiang, LI Bao-qing, ZHANG Bi-jiang. Copyrolysis of coal with coke-oven gas[J]. J Fuel Chem Technol, 1998, 26(1):13-17. http://www.cnki.com.cn/Article/CJFDTOTAL-RLHX903.009.htm [16] BLANDER M. The inorganic chemistry of the combustion of aspen wood with added sulfur[J]. Biomass Bioenergy, 1997, 12(4):289-293. doi: 10.1016/S0961-9534(96)00081-5 [17] DAVIDSSON K O, KORSGREN J G, PETTERSSON J B C, JÄGLID U. The effects of fuel washing techniques on alkali release from biomass[J]. Fuel, 2002, 81(2):137-142. doi: 10.1016/S0016-2361(01)00132-6 [18] 刘垒, 张相龙, 李博仑, 王昶, 郝庆兰.预处理方法对植物生物质中钾元素含量测定的影响[J].天津科技大学学报, 2013, 28(5):38-41. http://www.cnki.com.cn/Article/CJFDTOTAL-TQYX201305008.htmLIU Lei, ZHANG Xiang-long, LI Bo-lun, WANG Chang, HAO Qing-lan. Effect of pretreatment on the measurement of potassium content in plant biomass[J]. J Tianjin Univ Sci Technol, 2013, 28(5):38-41. http://www.cnki.com.cn/Article/CJFDTOTAL-TQYX201305008.htm [19] 肖劲, 李发闯, 邓松云, 仲奇凡, 赖延清, 李劼.酸碱脱灰对煤结构及其热解特性的影响[J].中南大学学报(自然科学版), 2016, 47(1):14-19. doi: 10.11817/j.issn.1672-7207.2016.01.003XIAO Jin, LI Fa-chuang, DENG Song-yun, ZHONG Qi-fan, LAI Yan-qing, LI Jie. Influence of demineralization on structure and pyrolysis characteristics of coal with acid-alkali method[J]. J Cent South Univ (Sci Technol), 2016, 47(1):14-19. doi: 10.11817/j.issn.1672-7207.2016.01.003 [20] RICHARDS G N, ZHENG G. Influence of metal ions and of salts on products from pyrolysis of wood:Applications to thermochemical processing of newsprint and biomass[J]. J Anal Appl Pyrolysis, 1991, 21(1):133-146. http://www.sciencedirect.com/science/article/pii/016523709180021Y [21] KEILUWEIT M, NICO P S, JOHNSON M G, KLEBER M. Dynamic molecular structure of plant biomass-derived black carbon (biochar)[J]. Environ Sci Technol, 2010, 44(4):1247-1253. doi: 10.1021/es9031419 [22] BUSTIN R M, GUO Y. Abrupt changes (jumps) in reflectance values and chemical compositions of artificial charcoals and inertinite in coals[J]. In J Coal Geol, 1999, 38(3):237-260. http://www.sciencedirect.com/science/article/pii/S0166516298000251 [23] DAS D D, SCHNITZER M I, MONREAL C M, MAYER P. Chemical composition of acid-base fractions separated from biooil derived by fast pyrolysis of chicken manure[J]. Bioresour Technol, 2009, 100(24):6524-6532. doi: 10.1016/j.biortech.2009.06.104 [24] AHMAD M, LEE S S, DOU X, MOHAN D, SUNG J K, YANG J E, OK Y S. Effects of pyrolysis temperature on soybean stover-and peanut shell-derived biochar properties and TCE adsorption in water[J]. Bioresour Technol, 2012, 118:536-544. doi: 10.1016/j.biortech.2012.05.042 [25] 高松平, 赵建涛, 王志青, 王建飞, 房倚天, 黄戒介. CO2对褐煤热解行为的影响[J].燃料化学学报, 2013, 41(3):257-264. http://rlhxxb.sxicc.ac.cn/CN/abstract/abstract18131.shtmlGAO Song-ping, ZHAO Jian-tao, WANG Zhi-qing, WANG Jian-fei, FANG Yi-tian, HUANG Jie-jie. Effect of CO2 on pyrolysis behaviors of lignite[J]. J Fuel Chem Technol, 2013, 41(3):257-264. http://rlhxxb.sxicc.ac.cn/CN/abstract/abstract18131.shtml [26] 冯杰, 李文英, 谢克昌.傅立叶红外光谱法对煤结构的研究[J].中国矿业大学学报, 2002, 31(5):362-366. http://www.cnki.com.cn/Article/CJFDTOTAL-ZGKD200205005.htmFENG Jie, LI Wen-ying, XIE Ke-chang. Research on coal structure using FT-IR[J]. J China Univ Min Technol, 2002, 31(5):362-366. http://www.cnki.com.cn/Article/CJFDTOTAL-ZGKD200205005.htm [27] ZHANG X, DONG L, ZHANG J, TIAN Y, XU G. Coal pyrolysis in a fluidized bed reactor simulating the process conditions of coal topping in CFB boiler[J]. J Anal Appl Pyrolysis, 2011, 91(1):241-250. doi: 10.1016/j.jaap.2011.02.013 [28] 付鹏, 胡松, 向军, 孙路石, 张安超, 杨涛, 江龙.生物质颗粒孔隙结构在热解过程中的变化[J].化工学报, 2009, 60(7):1793-1799. http://www.cnki.com.cn/Article/CJFDTOTAL-HGSZ200907031.htmFU Peng, HU Song, XIANG Jun, SUN Lu-shi, ZHANG An-chao, YANG Tao, JIANG Long. Evolution of pore structure of biomass particles during pyrolysis[J]. J Chem Ind Eng, 2009, 60(7):1793-1799. http://www.cnki.com.cn/Article/CJFDTOTAL-HGSZ200907031.htm [29] CETIN E, GUPTA R, MOGHTADERI B. Effect of pyrolysis pressure and heating rate on radiata pine char structure and apparent gasification reactivity[J]. Fuel, 2005, 84(10):1328-1334. doi: 10.1016/j.fuel.2004.07.016 [30] WU S, GU J, ZHANG X, WU Y, GAO J. Variation of carbon crystalline structures and CO2 gasification reactivity of Shenfu coal chars at elevated temperatures[J]. Energy Fuels, 2007, 22(1):199-206. doi: 10.1021/ef700371r