基于冷指的不同防蜡率计算方法分析

防蜡率的测定对防蜡剂的有效筛选具有重要意义。考虑到标准中推荐的防蜡率计算方法的局限性,利用自行改造的冷指装置对不同温度、剪切强度和作用时间下加剂前后的蜡沉积物进行了测定,并给出了两种不同的防蜡率计算方法。结果表明:防蜡率与防蜡沉积速率随温度区间的变化规律基本一致,油温为47℃、壁温为37℃时的防蜡沉积速率为99.83%,明显高于防蜡率;防蜡沉积速率与防蜡率随剪切强度的变化规律基本一致;作用时间较短时,防蜡沉积速率比防蜡率大,超过4 h后两者基本不再随时间变化;所用防蜡剂对各碳数的防蜡效果各异,对C44之前的碳具有防蜡效果,C44及其以后的碳具有负面作用。在实际使用时应根据具体实际情况合理选取或三种防蜡率计算方法结合起来使用。

Analysis on Different Determination Methods of Paraffin Inhibition Efficiency Based on Cold Finger

Paraffin inhibition efficiency determination is significant to the selection of paraffin inhibitor.Considering the limitation of paraffin inhibition efficiency calculation method recommended in standard,the wax deposit before and after adding paraffin inhibitor at different temperature,shear strength and action time were determined by using self-reconstructive cold finger device,and two different paraffin inhibition efficiency calculation methods were given.The results showed that:change rules of paraffin inhibition efficiency and wax deposition inhibition efficiency against temperature interval were basically the same,wax deposition inhibition efficiency was 99.83％ and greater than the paraffin inhibition efficiency apparently when the oil temperature was 47 ℃ and wall temperature was 37 ℃;change rules of paraffin inhibition efficiency and wax deposition inhibition efficiency against shear strength were basically the same;wax deposition inhibition efficiency was greater than paraffin inhibition efficiency when the action time was shorter,and there was no change when the action time was more than 4 h;the paraffin inhibition effects of used paraffin inhibitor to each carbon number were different,having effect to the carbon before C44 while having a side effect to the carbon after C44.In practice use,we should select suit method based on the actual condition or combine these three paraffin inhibition efficiency calculation methods.