烷基烯酮二聚体对褐煤疏水改性及成浆性能的影响

doi:10.16085/j.issn.1000-6613.2019-0044

摘要/Abstract

摘要：

针对褐煤表面亲水基团丰富、孔隙发达导致煤成浆性能差的问题，以阳离子表面活性剂十六烷基三甲基溴化铵（CTAB）为乳化剂制备了阳离子烷基烯酮二聚体（AKD）乳液，将其涂覆在经微波脱水后的褐煤颗粒表面，使煤样表面获得较强的疏水性；利用比表面积分析仪（BET）、X射线光电子能谱（XPS）和化学滴定法研究了AKD与煤表面的作用机理，同时测定了煤水体系的zeta电位以及煤水界面润湿性，结果表明AKD在煤表面发生了物理化学吸附，并当阳离子AKD乳液用量为1.5%时，改性煤粒表面zeta电位绝对值达到最大，褐煤与水的接触角从50.92°增加到121.10°；再将改性后的褐煤颗粒配合聚萘磺酸盐分散剂制得高浓度的水煤浆，当褐煤水煤浆黏度保持1000mPa·s时，最大成浆浓度从原煤的56.6%增加到61.20%，并且随水煤浆存放时间的延长其水煤浆的黏度保持稳定。

关键词: 褐煤, 疏水改性, 水煤浆, 流变学, 稳定性

Abstract:

The abundant pore structure and the large number of oxygen-containing groups cause the high water content of lignite, which limits its efficient utilization. A cationic alkyl ketene dimer (AKD) emulsion was prepared by using cationic surfactant cetyltrimethylammonium bromide (CTAB) as emulsifier. Then the AKD emulsion was coated on the surface of lignite particles after microwave dehydration to improve the hydrophobic properties of coal particles. The action mechanism of AKD and coal surface was investigated by utilizing specific surface area analyzer (BET), X-ray photoelectron spectroscopy (XPS) and chemical titration. The zeta potential of coal water system and the wettability of coal water interface were also determined. The results showed that AKD had physical and chemical adsorption on the surface of the coal when the amount of the cationic AKD emulsion was 1.5%, the absolute value of zeta potential on the surface of the modified coal particle reached the maximum, and the contact angle of the lignite and water was increased from 50.92° to 121.10°. After adding polynaphthalene sulfonate dispersant, the concentration of coal water slurry prepared by modified coal particles was higher. When the viscosity of coal water slurry was 1000mPa·s, the maximum concentration of coal water slurry increased from 56.6% to 61.2%. And the viscosity of coal water slurry remained stable with the prolongation of storage time.

Key words: lignite, hydrophobic modification, coal water slurry, rheology, stability

中图分类号:

TQ536.1

郭晶,张光华,张万斌,朱军峰,吴江,杜伦. 烷基烯酮二聚体对褐煤疏水改性及成浆性能的影响[J]. 化工进展, 2019, 38(10): 4705-4711.

Jing GUO,Guanghua ZHANG,Wanbin ZHANG,Junfeng ZHU,Jiang WU,Lun DU. Effect on surface hydrophobic modification and slurribility of lignite coal by alkyl ketone dimer[J]. Chemical Industry and Engineering Progress, 2019, 38(10): 4705-4711.

图/表 11

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煤样	含氧官能团相对含量/%
煤样	C—O—C/ C—O—H	C═O	O—C═O	C—H/ C—C
原煤	23.42	12.90	9.21	54.45
微波干燥煤	23.15	11.98	7.90	56.90
1.5%AKD改性煤	17.48	12.20	10.41	59.91

煤样	含氧官能团相对含量/%
煤样	C—O—C/ C—O—H	C═O	O—C═O	C—H/ C—C
原煤	23.42	12.90	9.21	54.45
微波干燥煤	23.15	11.98	7.90	56.90
1.5%AKD改性煤	17.48	12.20	10.41	59.91

煤样	总酸/mmol·g^-1	羧基/mmol·g^-1	酚羟基/mmol·g^-1
原煤	2.800	0.425	2.375
微波干燥煤	1.800	0.325	1.475
1.5%AKD改性煤	1.000	0.301	0.699

煤样	总酸/mmol·g^-1	羧基/mmol·g^-1	酚羟基/mmol·g^-1
原煤	2.800	0.425	2.375
微波干燥煤	1.800	0.325	1.475
1.5%AKD改性煤	1.000	0.301	0.699

煤样	比表面积/m²·g^-1	孔容积/cm3·g^-1	平均孔径/nm
原煤	8.592	0.034	20.136
微波干燥煤	8.525	0.031	19.682
1.5%AKD改性煤	3.098	0.024	19.028