Effect of ionic liquid on the spontaneous combustion characteristics of noncaking pulverized coal
-
摘要: 為了研究煤粉儲運過程中堆積煤粉在漏風環境下氧化升溫導致其氧化自燃特征，揭示[BMIM][BF4]離子液體抑制煤粉氧化阻燃反應機制。本文選用高效阻化劑[BMIM][BF4]離子液體對紅柳煤礦(HL)不粘煤煤粉進行阻化處理，通過煤粉恒溫氧化實驗測定5%、10%、15%質量分數的[BMIM][BF4]處理煤粉的自燃臨界參數，即煤粉臨界自燃溫度Tm和著火延遲時間ti，分析[BMIM][BF4]對煤粉加熱、自熱反應的影響；測試同一高溫環境下(各煤粉均被點燃)[BMIM][BF4]對煤粉的宏觀阻化特性；通過FT-IR實驗表征[BMIM][BF4]對煤粉的微觀阻化特征，驗證煤粉自燃臨界參數變化規律。結果表明：[BMIM][BF4]能夠抑制煤粉自熱反應并提高煤粉Tm和ti值，降低煤粉自燃危險性，且其質量分數越大，煤粉自燃臨界參數越大，其中15%質量分數的[BMIM][BF4]處理煤粉的Tm為156 ℃，較原煤粉冗余度提高+26 ℃，ti為80 min，較原煤粉著火延遲32 min。在同一環境溫度Ta下(Ta>Tm)，[BMIM][BF4]處理煤粉的中心點溫度、耗氧速率、CO產生量均小于原煤粉，且[BMIM][BF4]的阻化效果隨質量分數的增大而增大。[BMIM][BF4]的阻化作用體現在強電負性氟原子與煤中羥基氫原子形成較強的氫鍵，溶解破壞煤中羥基基團，阻斷煤氧鏈式反應。Abstract: To study the oxidation behavior induced by the spontaneous combustion of accumulated pulverized coal during its storage and transportation within an air leakage circumstance during increased oxidation and temperature and to reveal the mechanism of [BMIM][BF4] ionic liquid inhibiting oxidation and flame retardant characteristics of pulverized coal, this paper used a high-efficiency inhibitor [BMIM][BF4] ionic liquid to inhibit the noncaking coal pulverized coal of the Hongliu coal mine (HL), measuring the critical parameters (critical spontaneous combustion temperature, Tm, and ignition delay time, ti) of pulverized coal spontaneous combustion treated using [BMIM][BF4] at 5%, 10%, and 15% mass fraction. This work also analyzed the influence of [BMIM][BF4] on the heating and self-heating of the pulverized coal. Macroscopic resistance characteristics of [BMIM][BF4] to the pulverized coal were tested under the same high-temperature circumstance (all pulverized coals were ignited). Furthermore, an Fourier transform infrared experiment was used to characterize the microscopic resistance characteristics of the pulverized coal by [BMIM][BF4] to verify the variation of the critical parameters during pulverized coal spontaneous combustion. Results show that [BMIM][BF4] can efficiently inhibit the self-heating reaction of the pulverized coal, increase the Tm and ti values of the pulverized coal, and reduce the risk of pulverized coal spontaneous combustion. Moreover, a higher [BMIM][BF4] mass fraction results in a greater critical parameter of pulverized coal spontaneous combustion. Among them, the Tm of the coal powder treated by [BMIM][BF4] at a 15% mass fraction is 156 ℃, which is +26 ℃ longer than the original pulverized coal redundancy, and the ti is 80 min, which is 32 min later than the original pulverized coal ignition. Under a similar experimental temperature, Ta (Ta>Tm), the center point temperature, oxygen consumption rate, and CO production of pulverized coal treated by [BMIM][BF4] are all lower than those of the original pulverized coal, and the inhibition effect is enhanced with the increase in the mass fraction of [BMIM][BF4]. Meanwhile, the inhibited effect of [BMIM][BF4] is reflected in the strong electronegative fluorine atoms forming strong hydrogen bonds with the hydroxyl hydrogen atoms in coal, dissolving and destroying the hydroxyl groups in the coal and blocking the coal oxygen chain reaction.
-
圖 3 原煤粉在兩種環境溫度下的氧化進程. (a) 原煤粉中心點溫度變化; (b) 原煤粉氧氣質量分數變化
Figure 3. Oxidation process of the original pulverized coal at two ambient temperatures: (a) temperature change at the center point of the original pulverized coal; (b) oxygen mass fraction change of the original pulverized coal
圖 4 離子液體處理煤粉在兩種環境溫度下的升溫曲線. (a) 5%?[BMIM][BF4]; (b) 10%?[BMIM][BF4]; (c) 15%?[BMIM][BF4]
Figure 4. Temperature rise curves of the pulverized coal treated by ionic liquid at two ambient temperatures: (a) 5%?[BMIM][BF4]; (b) 10%?[BMIM][BF4]; (c) 15%?[BMIM][BF4]
圖 8 紅外光譜曲線. (a) [BMIM][BF4]的吸光度; (b) 15%?[BMIM][BF4]與原煤粉的吸光度對比
Figure 8. Infrared spectrum curve: (a) absorbance of [BMIM][BF4]; (b) comparison of absorbance between 15%?[BMIM][BF4] and original pulverized coal
圖 9 煤粉主要吸收峰面積變化
Figure 9. Change of the main absorption peak area of the pulverized coal
表 1 煤樣工業分析
Table 1. Industrial analysis of the coal sample
Sample Mass fraction/% Moisture (Mad) Ash (Aad) Volatiles (Vad) Fixed carbon (FCad) HL 2.62 16.18 35.27 45.93 
下載: 導出CSV
表 2 煤樣元素分析
Table 2. Element analysis of the coal sample
Sample Mass fraction/% Carbon (Cad) Hydrogen (Had) Oxygen (Oad) Nitrogen (Nad) Sulfur (Sad) HL 68.11 4.61 6.54 1.78 0.16
下載: 導出CSV
表 3 [BMIM][BF 4]和煤粉的配比
Table 3. Mixing ratio of [BMIM][BF4] and pulverized coal
Samples Mass fraction of [BMIM][BF4]/% Pulverized coal: Water: Ionic liquid (mass ratio) 5%?[BMIM][BF4] 5 100∶47.5∶2.5 10%?[BMIM][BF4] 10 100∶45∶5 15%?[BMIM][BF4] 15 100∶42.5∶7.5
下載: 導出CSV
中文字幕在线观看表 4 煤粉自燃臨界參數
Table 4. Critical parameters of pulverized coal spontaneous combustion
Pulverized coal Tm/℃ ti/min Original pulverized coal 130 48 5%?[BMIM][BF4] 136 55 10%?[BMIM][BF4] 142 67 15%?[BMIM][BF4] 156 80
下載: 導出CSV
-
參考文獻
[1] Chao C Y, Wu K, Du R L, et al. Combustion characteristics and kinetic analysis of pulverized coal and semicoke. Chin J Eng, 2016, 38(11): 1532巢昌耀, 吳鏗, 杜瑞嶺, 等. 煤粉與半焦的混合燃燒特性及動力學分析. 工程科學學報, 2016, 38(11):1532 [2] Liu X L, Zhang Q. Influence of turbulence flow on explosion characteristics of coal dust in 20L vessel. J China Coal Soc, 2018, 43(11): 3137 doi: 10.13225/j.cnki.jccs.2018.0099劉雪嶺, 張奇. 密閉空間煤粉氣動分散湍流對爆炸參數的影響規律. 煤炭學報, 2018, 43(11):3137 doi: 10.13225/j.cnki.jccs.2018.0099 [3] Liu B, Qi Y G, Zhang F N, et al. The impinging depth of coal particles cleanout jet device for coalbed methane well. J China Coal Soc, 2014, 39(4): 713劉冰, 綦耀光, 張芬娜, 等. 煤層氣井射流沖煤粉裝置沖擊深度的研究. 煤炭學報, 2014, 39(4):713 [4] Li L, Chen J C, Jiang D Y, et al. Experimental study on temporal variation of high temperature region and index gas of coal spontaneous combustion. J China Coal Soc, 2016, 41(2): 444李林, 陳軍朝, 姜德義, 等. 煤自燃全過程高溫區域及指標氣體時空變化實驗研究. 煤炭學報, 2016, 41(2):444 [5] European Committee for Standardization. EN15188—2007 Determination of the Spontaneous Ignition Behaviour of Dust Accumulations. Brussels: CEN-CENELEC, 2007 [6] Wu D J, Norman F, Schmidt M, et al. Numerical investigation on the self-ignition behaviour of coal dust accumulations: The roles of oxygen, diluent gas and dust volume. Fuel, 2017, 188: 500 doi: 10.1016/j.fuel.2016.10.063 [7] Liu T Q. Experimental test on the minimum ignition temperature and minimum ignition energy of the coal dust cloud. J Saf Environ, 2020, 20(4): 1334劉天奇. 不同煤質煤塵云最低著火溫度與最小著火能量試驗. 安全與環境學報, 2020, 20(4):1334 [8] Wu D J, Huang X Y, Norman F, et al. Experimental investigation on the self-ignition behaviour of coal dust accumulations in oxy-fuel combustion system. Fuel, 2015, 160: 245 doi: 10.1016/j.fuel.2015.07.050 [9] Ying Z, Zheng X Y, Cui G M. Pressurized oxy-fuel combustion performance of pulverized coal for CO2 capture. Appl Therm Eng, 2016, 99: 411 doi: 10.1016/j.applthermaleng.2016.01.023 [10] Ma L, Li C H, Wu R L, et al. Experimental study on spontaneous combustion characteristics of pulverized coal under minimum ignition temperature. Coal Sci Technol, 2020, 48(2): 110馬礪, 李超華, 武瑞龍, 等. 最低點火溫度條件下煤粉自燃特性試驗研究. 煤炭科學技術, 2020, 48(2):110 [11] Joshi K A, Raghavan V, Rangwala A S. An experimental study of coal dust ignition in wedge shaped hot plate configurations. Combust Flame, 2012, 159(1): 376 doi: 10.1016/j.combustflame.2011.06.003 [12] Lebecki K, Dyduch Z, Fibich A, et al. Ignition of a dust layer by a constant heat flux. J Loss Prev Process Ind, 2003, 16(4): 243 doi: 10.1016/S0950-4230(03)00041-X [13] Park H, Rangwala A S, Dembsey N A. A means to estimate thermal and kinetic parameters of coal dust layer from hot surface ignition tests. J Hazard Mater, 2009, 168(1): 145 doi: 10.1016/j.jhazmat.2009.02.010 [14] Xiao C W. Study on explosion characteristics of pulverized coal and explosion proof measures of coal bunker. Coal Sci Technol, 2016, 44(8): 188肖翠微. 煤粉爆炸特性與煤粉倉防爆措施研究. 煤炭科學技術, 2016, 44(8):188 [15] Song C L, Liu X R, Zhao S S, et al. Flame retardancy of anions in imidazolium-based ionic liquids on Xinjiang lignite. J China Coal Soc, 2020, 45(Suppl 1): 470宋長磊, 劉向榮, 趙順省, 等. 咪唑類離子液體中陰離子對新疆褐煤阻燃性能. 煤炭學報, 2020, 45(增刊1): 470 [16] Hu Z Q, Zhang S F, Lei Z P, et al. Study on the thermal extraction of Xianfeng lignite in ionic liquid 1-butyl-3-methyl-imidazolium trifluoromethanesulfonate. J Fuel Chem Technol, 2015, 43(5): 513 doi: 10.1016/S1872-5813(15)30014-1 [17] Saida S, Chakravaty S, Sahu R N, et al. Laboratory-scale tests for the utilization of high ash non-coking coal in coke-making process. Trans Indian Inst Met, 2020, 73(5): 1257 doi: 10.1007/s12666-020-01974-0 [18] Wang L Y, Xu Y L, Jiang S G, et al. Imidazolium based ionic liquids affecting functional groups and oxidation properties of bituminous coal. Saf Sci, 2012, 50(7): 1528 doi: 10.1016/j.ssci.2012.03.006 [19] Zhong X X, Wang D M, Yin X D. Test method of critical temperature of coal spontaneous combustion based on the temperature programmed experiment. J China Coal Soc, 2010, 35(Suppl 1): 128仲曉星, 王德明, 尹曉丹. 基于程序升溫的煤自燃臨界溫度測試方法. 煤炭學報, 2010, 35(增刊1): 128 [20] Xu Y L, Wang L Y, Song Z P, et al. Characteristics and critical parameters of coal spontaneous combustion at low temperature stage based on CPT method. J China Coal Soc, 2017, 42(4): 935 doi: 10.13225/j.cnki.jccs.2017.0042徐永亮, 王蘭云, 宋志鵬, 等. 基于交叉點法的煤自燃低溫氧化階段特性和關鍵參數. 煤炭學報, 2017, 42(4):935 doi: 10.13225/j.cnki.jccs.2017.0042 [21] Ma L, Zou L, Ren L F, et al. Prediction indices and limiting parameters of coal spontaneous combustion in the Huainan mining area in China. Fuel, 2020, 264: 116883 doi: 10.1016/j.fuel.2019.116883 [22] Painter P, Pulati N, Cetiner R, et al. Dissolution and dispersion of coal in ionic liquids. Energy Fuels, 2010, 24(3): 1848 doi: 10.1021/ef9013955 [23] Zhang W Q. Fundamental Research on Effect of Imidazolium-based and Phosphonium-based Room Temperature Ionic Liquids on Coal Oxidation Properties [Dissertation]. Xuzhou: China University of Mining and Technology, 2013張衛清. 咪唑類和季膦鹽類室溫離子液體影響煤氧化特性的基礎研究[學位論文]. 徐州: 中國礦業大學, 2013 [24] Li H J, Li X H, Feng J, et al. Effect of preheating treatment on oxygen migration during lignite pyrolysis. J Fuel Chem Technol, 2019, 47(1): 1 doi: 10.3969/j.issn.0253-2409.2019.01.001李海杰, 李曉紅, 馮杰, 等. 預熱處理對褐煤熱解過程氧元素遷移的影響. 燃料化學學報, 2019, 47(1):1 doi: 10.3969/j.issn.0253-2409.2019.01.001 [25] Cummings J, Tremain P, Shah K, et al. Modification of lignites via low temperature ionic liquid treatment. Fuel Process Technol, 2017, 155: 51 doi: 10.1016/j.fuproc.2016.02.040 [26] Wang L Y, Xu Y L, Ji Y P, et al. Effect of ionic liquids with imidazolium based cations substituted by different oxygen-containing groups on coal oxidation. J China Coal Soc, 2012, 37(7): 1190王蘭云, 徐永亮, 姬宇鵬, 等. 含氧取代咪唑類離子液體影響煤結構及其氧化性質的實驗研究. 煤炭學報, 2012, 37(7):1190 [27] Deng J, Bai Z J, Xiao Y, et al. Effects on the activities of coal microstructure and oxidation treated by imidazolium-based ionic liquids. J Therm Anal Calorim, 2018, 133(1): 453 doi: 10.1007/s10973-018-7310-z [28] Zhao J Y, Zhang Y L, Deng J, et al. Key functional groups affecting the release of gaseous products during spontaneous combustion of coal. Chin J Eng, 2020, 42(9): 1139趙婧昱, 張永利, 鄧軍, 等. 影響煤自燃氣體產物釋放的主要活性官能團. 工程科學學報, 2020, 42(9):1139 -
點擊查看大圖
圖(10) / 表(4)
計量
- 文章訪問數: 547
- HTML全文瀏覽量: 173
- PDF下載量: 40
- 被引次數: 0
