季铵盐双子表面活性剂对石油焦成浆性能的影响及机理研究

Petroleum coke is a promising material for preparing petroleum coke water slurry (PCWS) as a feedstock of gasification to generate hydrogen for the processing of the crude oil, which is significant for the cost-reduction of the oil refinery. But the static stability and rheological behavior of PCWS is hard to meet the industrial requirement, which seriously restricts its application and development. In this study, a series of quaternary ammonium Gemini surfactant with different length of hydrophobic chains, synthesized by the laboratory of the applicant, are compounded with naphthalene sulfonate formaldehyde condensate sodium salt (NSF) or modified sodium lignosulfonate (SL) to improve the rheology of PCWS, and the compounding principle and the slurrying mechanism are systematically investigated. The adsorption behavior of the compounding dispersants with quaternary ammonium Gemini surfactant and NSF/SL on the surface of petroleum coke particles, their aggregation behavior in the liquid phase of PCWS, and the interaction effects and mechanisms of the two behaviors are studied. The effects of the compounding dispersants on the surface properties of petroleum coke particles are studied. Moreover, the influence of the compounding dispersants on the properties of PCWS is investigated. Based on the above analyses, the relationship of the structure of quaternary ammonium Gemini surfactant, the compounding formulation and the properties of PCWS is to be established. The structure-activity relationship and mechanism of the compounding dispersants on the interface of petroleum coke and water is to be revealed, and the methods and principles of designing and controlling the structure of quaternary ammonium Gemini surfactant could be proposed from the aspect of optimizing the properties of PCWS, which will provide the theory basis for the promotion of the PCWS processing.

石油焦制备成水焦浆用于气化制氢对于降低原油加工成本具有重要意义，但水焦浆流变性能较差，严重制约了它的推广应用。本项目合成一系列不同疏水链长的季铵盐双子表面活性剂作为分散剂助剂与NSF（萘磺酸盐甲醛缩合物钠盐）/SL（改性木质素磺酸钠）复配用于改善水焦浆的流变性能，并对二者的复配原则和成浆机制进行系统研究。具体内容包括：季铵盐双子表面活性剂和NSF/SL复配型分散剂在石油焦颗粒表面的吸附行为、在水溶液中的聚集行为及其对吸附行为的影响规律；该分散剂体系对石油焦颗粒表面性质的影响规律及该体系对水焦浆成浆性质的影响机制。在此基础上，建立“季铵盐双子表面活性剂结构—分散剂配方—石油焦成浆性质”三者之间的联系，揭示该分散剂体系在石油焦/水界面的构效与作用机理，并从优化水焦浆的性质出发提出设计和调控季铵盐双子表面活性剂分子结构的方法和原则，为水焦浆工艺的推广提供理论依据。

石油焦碳含量高、水含量低、孔隙少，适合制备高浓度的水焦浆（一般超过 65%），然而水焦浆的稳定性较差，在极短的时间内即产生硬沉淀且大多属于胀塑性流体，难以满足气化进料的要求，因此如何改善水焦浆的流变性能成为石油焦气化利用领域亟待解决的攻关难题。本项目采用自主合成的季铵盐双子表面活性剂14-3(OH)-14(2Cl)（G14）改性石油焦和混配低阶煤两种方式改善了水焦浆的成浆性质。取得的主要成果如下：1. 采用G14预吸附的方式对石油焦进行改性，并通过分子动力学模拟和实验相结合的手段考察NSF在G14改性石油焦颗粒表面的吸附机制，探索G14改性石油焦制备水焦浆的成浆机制。2. 研究G14与邻苯二甲酸氢钠构筑的具有高粘弹特性的蠕虫状胶束混合体系对pH、温度双重刺激响应行为。3. 选用岚桥石油焦和连云港石油焦分别与哈密低阶煤混配制备水煤焦浆，考察石油焦的性质对水煤焦浆成浆性质的影响机制。4. 应用自主合成的石油焦专用四元两性聚羧酸盐分散剂PC，并对比了PC、G14&NSF和NSF三个分散剂配方制备的水焦浆性质。基于以上研究成果，完成了本项目立项之初设定的研究目标，研究工作有望为水焦浆和水煤焦浆用于气化提供指导。