新疆准东地区中阶煤制水煤浆生物质基高效分散剂的合成及性能研究

A series of novel biomass based efficient dispersing agents of coal water slurry with mutiple funtional groups including amino, carboxy, sulfoacid and aryl group were designed and synthesised, using local rich cotton straw in Xinjiang as raw material, the performance of the dispersing agents was adjusted by changing the structure and substitution degree of functional groups. The slurryability of the dispersant was studied with the medium rank coal in Xinjiang ZhunDong as application object. Semi-empirical method from the method of quantumchemistry calculation and B3LYP/6-31G method by Gaussian software were employed to study the structure-activity relationship and dose-effect relationship of the dispersing agents. In addition, mechanism of action and controllable regularity between the molecular structure of additives and the medium rank coal particles were revealed. This work would supply a certain theoretical direction for the molecular design and tailor of the dispersing agents to slurry ability. Fractal theory was used to simulate the slurry formation mechanism of the medium rank coal and study the effect of parameters such as the medium rank coal particle size, interspace, specific surface area and dispersing agents dose on the property of water-coal-slurry. Finally, the fractal-dimension relationship between the dose of dispersing agents to slurry ability and the medium rank coal particle could be predicted and revealed. The theoretical basis for the application of the medium rank coal in Xinjiang ZhunDong was then supplied.

以新疆当地丰富的棉秸秆为原料，设计合成一系列新型的生物质基含有氨基、羧基、磺酸基和芳环的多官能团高效水煤浆分散剂，调节官能团结构和取代度来调控其性能。以新疆准东丰富的中阶煤资源为应用对象，研究该类分散剂的性能。运用量子化学计算方法中的半经验计算方法和Gaussian 软件 B3LYP/6-31G 方法，研究该类分散剂的构效、量效关系，揭示分散剂的分子结构与中阶煤颗粒的作用机理和可控规律。为该类分散剂的分子设计、剪裁提供一定的理论指导。运用分形理论模拟中阶煤成浆机理，研究中阶煤颗粒(尺寸)、空隙、比表面积及分散剂加入量等参数对水煤浆性质的影响，揭示和预测分散剂加入量与中阶煤颗粒分形维数的关系，为新疆准东中阶煤利用提供理论依据。

生物质定向转化技术和资源综合开发利用是各国研究的热点。针对新疆丰富的棉秸秆资源和煤炭资源，设计和制备出一系列超分子高效水煤浆分散剂，并成功应用于新疆准东中低阶煤制水煤浆中。. 按照项目研究计划，研究了棉秸秆中各种组分，设计合成了一系列功能性小分子，对纤维素进行改性。把功能性小分子接枝到纤维素大分子上，通过调控功能性小分子取代纤维素分子中羟基上的氢原子，得到一系列超分子水煤浆分散剂。应用合成的分散剂和准东煤，制备出了浓度大于60%符合国标的水煤浆。研究了分散剂的分散作用机理，通过对分散剂及作用在煤颗粒的Zeta电位进行研究，发现静电斥力是分散作用机理的内在因素，超分子分散剂分子链上存在磺酸基和羧基，吸附量最高可达到8.99 mg/g。分散剂吸附在煤颗粒表面，符合准二级动力学方程，化学反应占主导地位；吸附等温线符合Freundlich模型，为多分子层的吸附；热力学参数吉布斯自由能∆G<0，焓变∆H>0，熵变∆S>0，吸附为自发吸热反应。但是纤维素属于大分子结构，空间位阻效应明显，通过与静电斥力结合使得减水效果特别显著，表明了分散机理中，空间位阻的重要作用。研究了功能性小分子、分散剂的分子设计、合成工艺条件和水煤浆的成浆机理。此外，对纤维素进行了其他功能性改性，制备了高性能的纤维素基吸附材料。研究结果表明，以丰富的棉秸秆为原料，通过分子设计，可以制备系列功能材料，为棉秸秆高附加值利用提供一种新的可行性方法，因此本项目研究具有一定的重大科学研究意义和实际应用价值。