分子设计分散剂与新疆准东低阶煤吸附成浆控制机制的研究

The low rank coal has the characteristics of high volatile matter and high reactivity, which has accounted for about 50% of global coal consumption. Low-rank Coal is difficult to make high-concentration coal water slurry, because it has high containing water, pore structure and oxygenous groups. Therefore, it affect the utilization rate of coal and restrict the capacity of equipments. The performance of coal water slurry is controlled by the performance of coal surface. To prepare high concentration coal cater slurry we research the mechanism of dispersant modified the coal surface according to the character of low rank coal from Zhundong in Xinjiang. After analysis the surface properties of low rank coal, we design three dispersant with different structure and function. Furthermore, we investigate the adsorption behavior of dispersant on low rank coal, and analysis the change of low rank coal surface properties after adsorb dispersant including pore size, surface energy and surface electric properties. To understand the interaction mechanism between dispersant and coal, we research the adsorption thermodynamic and kinetic behaviors. We build structure-activity relationship from molecular conformation, absorption, dispersion and rheology, and it reveal dispersion stability rule and solution rheological mechanism of low rank coal and molecular designs of dispersant. Which provide the reference for the development of low rank coal of Zhundong.

低阶煤具有高挥发分、高反应活性等特点，在煤炭总消耗量中已超过50%。但因低阶煤内水高、孔隙发达、含氧基团多，难以实现高浓度制浆，影响了煤炭利用率、制约了装置产能。本项目基于煤表面性能决定水煤浆性能的基本思想，针对新疆准东低阶煤的特点，研究分散剂调控煤表面性能的机制以便利用低阶煤实现高浓度的制浆。通过对准东低阶煤的表面特性分析，设计制备三类不同结构和功能的分散剂，探讨不同结构分散剂在低阶煤表面的吸附行为，分析低阶煤吸附分散剂前后其孔径、表面能、表面电性能等表面性质的变化，研究上述变化对成浆性能的影响，探讨分散剂在低阶煤孔径和表面的吸附行为，开展吸附的动力学、热力学研究，摸清分散剂与煤相互作用机制，从分子构象、吸附、分散和流变角度出发，建立构效关系，揭示准东低阶煤的分散稳定规律与溶液流变机理，提出准东低阶煤水煤浆高效分散剂的分子设计原则，为开发准东低阶煤水煤浆高效利用提供参考。

迄今研究水煤浆分散剂在结构上可分为合成型高分子分散剂和可塑性基底进行改性分散剂两类。本课题的科学思想是以解决煤粒在水中高浓度低粘度高稳定的存在的问题为出发点，我们可以从分子水平上对分散剂进行设计。可通过将两种或两种以上小分子聚合或缩聚成一端亲水，一端对煤粒表面能有较好亲和力的分散剂；或者对一些可塑性基底进行亲疏水性改造，使之形成带有两亲性的基团。一款性能优良的分散剂需要能对煤粒的亲疏水性做出改变，并能有效的改变煤粒与水之间的界面结构。根据水煤浆分散剂被广泛接受的分散机理，它能提高煤粒之间静电斥力；增加煤粒之间空间位阻；改善煤粒表面润湿分散性。这样的分散剂一端可以紧拉着煤粒，另一端将水分子保留在煤粒表面。本文将基于对前人工作，分别设计制备出木质素基、单宁基和合成高分子三种分散剂。设计出的水煤浆分散剂相比与同类及萘磺酸盐类分散剂对高阶煤和低阶煤都有很好的分散性能，并且制浆浓度高。现目前广泛使用的萘系分散剂，普适作用好。但是在制备更高浓度水煤浆其效果就不太理想。并且它是链状结构，基于此我的设计方案是对他的结构进行优化并将它设计成爪状萘系分散剂。