光敏电阻法测量表面活性剂在CO2中的浊点压力

Measurement of cloud-point pressure of surfactants in CO by photo resistance method

浊点压力是描述CO2复合体系相行为的重要参数,目前确定浊点压力的主要方法是目测法,但是由于体系由澄清变浑浊是一个连续变化的过程,因此目测法存在很大误差。该文利用光敏电阻的阻值与感光强度成反比的特性,通过光敏电阻监测CO2体系的透光强度,得到电阻值随体系压力的变化曲线,通过曲线的拐点可以准确地确定体系的浊点压力。该方法可以有效地避免人为读数时的误差。同时,利用该方法评价了烷基聚醚表面活性剂在CO2体系中的浊点压力,考察了表面活性剂的结构、组成及烷基链长度对浊点压力的影响,可为亲CO2-亲油表面活性剂的选择和设计及CO2体系浊点压力的测试提供重要的方法和理论依据。

Cloud-point pressure is an important parameter to describe the phase behaviors of CO2 mixed systems, which is usually determined by the method of visual observation. However, since the process from clarification to turbidity is a continuous process, there is a big error in the visual method. In this paper, the resistance value of the photosensitive resistance is inversely proportional to the photosensitive intensity. The light transmission intensity of CO2 system is monitored by the photosensitive resistance, and the curve of resistance value changing with the system pressure is obtained. The cloud-point pressure of the system can be accurately determined through the inflection point of the curve. This method can effectively avoid the error of artificial reading. Meanwhile, the cloud-point pressure of alkyl polyether surfactants in CO2 system is evaluated by this method, and the influence of surfactant structure, composition and alkyl chain length on cloud point pressure is investigated, which can provide an important method and theoretical basis for the selection and design of CO2 oleophilic surfactant and the measurement of cloud-point pressure of CO2 system.