Abstract:The semi-coke used in metallurgical production will be affected by the water vapor generated by wet coke quenching and the combustion of returned furnace gas in the oven for dry distillation.In order to clarify the effect of water vapor on the pore structure and sulfur content of semi-coke, a low-rank coal was selected for pyrolysis experiments under different pyrolysis conditions, the effects of different final pyrolysis temperatures (500-900 ℃) and water vapor input rates (0, 20%, 40%, 60%) on the sulfur content in low-rank coal pyrolysis products were investigated. The change of pore structure and total sulfur relative content of semi-coke was analyzed by specific surface and pore size analyzer and sulfur determination instrument, and the occurrence form of sulfur-containing functional groups on the surface of semi-coke was analyzed by X-ray photoelectron spectroscopy. The experimental results showed that in an inert atmosphere, when the temperature becomes the limiting link, the sulfur removal effect is better at medium and low temperatures (500-700 ℃), and the further increase of the final pyrolysis temperature is not conducive to the sulfur removal. When water vapor is introduced into the pyrolysis process, at low temperature (500-600 ℃), a small amount (20%) of water vapor desulfurization is significant, and a large amount (40%-60%) of water vapor is not conducive to desulfurization. At this time, different forms of sulfur will be transformed into each other, and water vapor promotes sulfur to precipitate mainly in the form of gas phase. Under higher temperature conditions (700-800 ℃), although water vapor promotes the development of pore structure, sulfur cannot be precipitated in the form of gas phase. Under the combined action of water vapor and polycondensation, sulfur is mainly converted in the solid phase, resulting in a decrease in desulfurization rate.Under the condition of high temperature (900 ℃), water vapor seriously destroys the pore structure and makes sulfur mainly precipitate in the form of gas phase, which significantly improves the desulfurization rate, but it will generate some inorganic sulfur and organic sulfur which is difficult to decompose. Therefore, in the process of producing semi-coke in the oven for dry distillation, the production process in the middle and high temperature region should be strictly controlled, the entry of water vapor should be avoided, and the water vapor addition content in the low temperature region should be controlled below 20 % as far as possible.
折媛, 尤宽, 巨建涛, 刘诗薇, 邹冲, 徐玉芬. 干馏炉内水蒸气对兰炭热解过程中硫迁移的影响[J]. 钢铁, 2023, 58(8): 51-60.
SHE Yuan, YOU Kuan, JU Jiantao, LIU Shiwei, ZOU Chong, XU Yufen. Effect of water vapor on sulfur migration during pyrolysis of semi-coke in oven for dry distillation[J]. Iron and Steel, 2023, 58(8): 51-60.
[1] 赵金成,胡旭东,高晋生.煤热解中有机硫的变化[J].煤炭转化,1993,16(2): 77.(ZHAO J C, HU X D, GAO J S. Changes of organic sulfur in coal pyrolysis[J]. Coal Conversion, 1993,16(2):77.) [2] 张鹏奇. 高硫煤微波辐照过程中有机硫的转变与迁移机理研究[D].重庆:重庆大学,2017. (ZHANG P Q. Transformation and Migration Mechanism of Organic Sulfur in High Sulfur Coal During Microwave Irradiation[D]. Chongqing: Chongqing University, 2017.) [3] 聂忠华.高硫煤资源利用研究进展[J].价值工程, 2020, 39(16): 227.(NIE Z H. Research progress on utilization of high-sulfur coal resources[J]. Value Engineering, 2020,39(16): 227.) [4] 宁晓钧,党晗,张建良,等.低阶煤热解与兰炭生产工艺研究进展[J].钢铁, 2021, 56(1): 1.(NING X J, DANG H, ZHANG J L, et al. Research progress on low rank coal pyrolysis and semi-coke production process[J]. Iron and Steel, 2021,56(1):1.) [5] 彭学诚,苏耀,郭汉杰,等.煤中挥发分对热解过程的行为影响分析[J].中国冶金,2022,32(11):41. (PENG X C, SU Y, GUO H J, et al. Effect of volatiles in coal on pyrolysis behavior[J]. China Metallurgy, 2022, 32(11): 41.) [6] 宋伟明,周建安,李数,等.煤焦还原分解烧结烟气脱硫石膏的试验[J].钢铁,2019,54(11):110.(SONG W M, ZHOU J A, LI S, et al. Experiment on reduction decomposition of sintering flue gas desulfurization gypsum by coal char[J]. Iron and Steel, 2019, 54(11): 110.) [7] JORJANI E, YPERMAN J, CARLEER R, et al. Reductive pyrolysis study of sulfur compounds in different Tabas coal samples (Iran)[J]. Fuel, 2006, 85(1): 114. [8] 李梅,杨俊和,夏红波,等.典型炼焦高硫煤热解过程中硫迁移规律研究[J].煤炭转化,2013,36(4):41.(LI M, YANG J H, XIA H B, et al. Study on sulfur migration during pyrolysis of typical coking high sulfur coal[J]. Coal Conversion, 2013,36 (4):41.) [9] 程亚. 煤中噻吩硫的富集及其在不同气氛下的脱硫机理研究[D].内蒙古:内蒙古大学, 2020.(CHENG Y. Enrichment of Thiophene Sulfur in Coal and its Desulfurization Mechanism Under Different Atmospheres[D]. Inner Mongolia: Inner Mongolia University, 2020.) [10] HU H Q, ZHOU Q, ZHU S W, et al. Product distribution and sulfur behavior in coal pyrolysis[J]. Fuel Processing Technology,2003,85(8):849. [11] LING L X, ZHANG R G, WANG B J, et al. DFT study on the sulfur migration during benzenethiol pyrolysis in coal[J]. Journal of Molecular Structure: THEOCHEM, 2010, 952(1): 31. [12] 许俊杰. 水蒸气对煤热解过程硫迁移影响的ReaxFF-MD研究[D].哈尔滨:哈尔滨工业大学,2020.(XU J J. ReaxFF-MD Study on the Effect of Water Vapor on Sulfur Migration During Coal Pyrolysis[D].Harbin: Harbin Institute of Technology, 2020.) [13] WANG M,DU Q,LI Y P,et al. Effect of steam on the transformation of sulfur during demineralized coal pyrolysis[J]. Journal of Analytical and Applied Pyrolysis,2019,140(6):161. [14] 蔡佳鑫,林日亿,马强,等. 噻吩水热裂解反应机理研究[J]. 石油与天然气化工,2019,48(1):80.(CAI J X,LIN R Y,MA Q,et al. Study on the mechanism of hydrothermal cracking reaction of thiophene[J]. Chemical Engineering of Oil and Gas,2019,48(1):80.) [15] NAG N K. Hydrodesulfurization of polycyclic aromatics catalyzed by sulfided CoO-MoO3-Al2O3: The relative reactivities[J]. Journal of Catalysis, 1979, 57(3): 509. [16] 李世光. 煤热解和煤与生物质共热解过程中硫的变迁[D].大连:大连理工大学, 2006.(LI S G. Desulfurization of Coal during Pyrolysis and Copyrolysis with Biomass[D]. Dalian: Dalian University of Technology, 2006.) [17] CHEN H K, LI B Q, ZHANG B J. Decomposition of pyrite and the interaction of pyrite with coal organic matrix in pyrolysis and hydropyrolysis[J]. Fuel, 2000, 79(13):1627. [18] 李斌,曹晏,张建民,等.高硫煤热解部分气化过程中硫的变迁行为[J].环境科学, 2003, 24(2): 60.(LI B, CAO Y, ZHANG J M, et al. Transition behavior of sulfur during pyrolysis partial gasification of high sulfur coal[J]. Environmental Science, 2003,24(2): 60.) [19] 刘粉荣,李文,郭慧卿,等.XPS法研究煤表面碳官能团的变化及硫迁移行为[J]. 燃料化学学报, 2011,39(2): 81.(LIU F R, LI W, GUO H Q, et al. XPS method was used to study the changes of carbon functional groups and sulfur migration behavior on coal surface[J]. Journal of Fuel Chemistry, 2011,39(2): 81.) [20] SLYUSARSKIY K V, KADCHIK D Y, ASILBEKOV A K. Study on the pyrolysis of different coal in atmospheres of argon, carbon dioxide, and steam[J]. Journal of Physics: Conference Series, 2020, 1675(1):012066. [21] 代世峰,任德贻,宋建芳,等.应用XPS研究镜煤中有机硫的存在形态[J]. 中国矿业大学学报, 2002,31(3): 12.(DAI S F, REN D Y, SONG J F, et al. XPS study on the speciation of organic sulfur in vitrain[J]. Journal of China University of Mining and Technology, 2002,31(3): 12.) [22] 邢孟文. 煤热解过程中噻吩类有机硫释放特性的研究[D].太原:太原理工大学,2011. (XING M W.Study on the Release Characteristics of Thiophene Organosulfur During Coal Pyrolysis[D]. Taiyuan: Taiyuan University of Technology,2011.) [23] 张蓬洲,赵秀荣.用XPS研究我国一些煤中有机硫的存在形态[J]. 燃料化学学报, 1993,21(2): 205.(ZHANG P Z, ZHAO X R. XPS study on the forms of organic sulfur in some chinese coals[J]. Journal of Fuel Chemistry, 1993,21(2): 205.) [24] 李梅,杨俊和,张启锋,等.用XPS研究新西兰高硫煤热解过程中氮、硫官能团的转变规律[J]. 燃料化学学报, 2013, 41(11): 1287.(LI M, YANG J H, ZHANG Q F, et al. Transformation of nitrogen and sulfur functional groups during pyrolysis of New Zealand high sulfur coal by XPS[J]. Journal of Fuel Chemistry, 2013,41(11): 1287.) [25] 陈鹏.用XPS研究兖州煤各显微组分中有机硫存在形态[J]. 燃料化学学报, 1997,25(3): 47.(CHEN P. Speciation of organic sulfur in Yanzhou coal macerals studied by XPS[J]. Journal of Fuel Chemistry, 1997,25(3): 47.) [26] 张海洋.我国煤炭工业现状及可持续发展战略[J]. 煤炭科学技术, 2014, 42(s1): 281.(ZHANG H Y. Present situation and sustainable development strategy of China′s coal industry[J]. Coal Science and Technology, 2014, 42(s1): 281.) [27] JU J T,YOU K,LIU S W, et al. Effect of water vapor on pore structure, surface functional groups, and combustion performance of pyrolytic semicoke[J]. ACS Omega,2022,7(28) 24587. [28] 肖博文. 水蒸气对煤热解过程硫迁移影响的实验研究[D].哈尔滨:哈尔滨工业大学,2018.(XIAO B W. Experimental study on the Effect of Water Vapor on Sulfur Migration During Coal Pyrolysis[D].Harbin: Harbin Institute of Technology,2018.) [29] 刘艳华,车得福,徐通模.利用X射线光电子能谱确定煤及其残焦中硫的形态[J]. 西安交通大学学报, 2004,38(1): 101.(LIU Y H, CHE D F, XU T M. The speciation of sulfur in coal and its residual char was determined by X-ray photoelectron spectroscopy[J].Journal of Xi'an Jiaotong University, 2004,38(1): 101.) [30] 齐炜.炼焦过程中硫元素迁移规律研究[J].洁净煤技术,2014,20(1):34.(QI W. Study on sulfur migration during coking process[J]. Clean Coal Technology, 2014,20(1): 34.) [31] 孙成功,李保庆. 煤中有机硫形态结构和热解过程硫变迁特性的研究[J].燃料化学学报,1997,25(4):71.(SUN C G, LI B Q. Studies on the morphological structure of organic sulfur in coal and the changing characteristics of sulfur during pyrolysis[J]. Journal of Fuel Chemistry and Technology, 1997,25(4): 71.) [32] 徐铮. 高硫烟煤的热解脱硫过程和机理研究[D].沈阳: 沈阳化工大学,2022.(XU Z. Study on Pyrolysis Desulfurization Process and Mechanism of High Sulfur Bituminous Coal[D].Shenyang: Shenyang University of Chemical Technology,2022.) [33] ZHAI Y H,LI S,YAN W P,et al. Effects of water vapor and temperature on NOx and CO emissions during converter gas combustion[J]. Fuel, 2019, 256(15):115914.