DSC降温速率对含蜡油样析蜡特性的影响

Influence of cooling rate on the wax precipitation characteristic of waxy oil samples in DSC test

差示扫描量热法(DSC)可以用于原油析蜡过程研究,其具有用油量少、测试快、测量精度高的特点,能够准确得到析蜡点、含蜡量等参数。在DSC测试过程中,温降速率对蜡晶析出过程的过冷度、仪器的敏感性均有影响,进而影响析蜡特性曲线及测试结果准确性。对含蜡油样在DSC测试试验过程中受降温速率的影响进行分析,结果表明:随降温速率增加,油样的析蜡点呈线性下降趋势,测得油样的含蜡量呈先增大后减小的趋势。从热力学角度解释了产生上述现象的原因,最终确定了含蜡油样在DSC测试过程中合适的降温速率应为5℃/min。

When the differential scanning calorimetry （DSC） is applied to investigate the wax precipitation process of crude oil, it can measure the parameters （e.g. wax precipitation point, and wax content） accurately and fast, with little oil consumption. The cooling rate in the DSC test affects degree of under cooling and instrument sensitivity in the process of wax precipitation, and thus brings impacts on the wax precipitation characteristic curve and the accuracy of test results. In this paper, the influence of cooling rate on the waxy oil samples in the DSC test was analyzed. It is shown that, with the increasing of cooling rate, the wax precipitation point tends to decrease linearly, and the wax content increases and then decreases. Finally, the causes of these phenomena were analyzed from the perspective of thermodynamics. It is confirmed that the appropriate cooling rate of waxy oil samples in the DSC test should be 5 ℃/min. （4 Figures, 20 References）