加剂柴油凝点及冷滤点反弹回升的研究

STUDY ON SETTING POINT AND COLD FILTER PLUGGING POINT REVERSION OF DIESEL WITH COLD FLOW PROMOTER

加入低温流动性能改进剂生产的低凝柴油 ,在储存和使用过程中存在凝点、冷滤点反弹回升现象 ,因此对辽河原油的常压柴油、加氢裂化柴油进行了加剂研究。在低温储存条件下 ,实际加剂柴油的凝点、冷滤点反弹回升幅度比常规测试的反弹幅度大 ,在 0℃下放置 6小时直接测定的加剂常压柴油的凝点回升幅度已经达到或超过在室温下放置 3 5天的回升幅度。研究发现 ,加入低温流动性能改进剂能减缓蜡晶生长速度 ,但不能从根本上阻断蜡晶的生长。加剂柴油长时间处于低温时 ,柴油中的蜡晶逐渐长大 ,当蜡晶长大到某一定临界稳定尺寸时 ,会形成较大三维网状骨架 。

It is known that setting point and cold filter plugging point of low pour point diesel with cold flow promoter can reverse during the storage and use process. So adding cold flow promoter to atmospheric and hydrocracking diesel from Liaohe crude has been studied. The setting point and cold filter plugging point of the diesel with promoter reversed more greatly in low temperature than that measured in routine conditions. The setting point reversion level of atmospheric diesel with promoter which stored for 6 hours below 0℃ has reached or exceeded the reversion level of that stored for 35 days at ambient temperature. It is found that the paraffin crystal growth speed can be reduced by adding the cold flow promoter, but it cannot be inhibited completely. Being at low temperature for a long time, paraffin crystals in the diesel with cold flow promoter grow up gradually. When they grow up to a critical stable size, the bigger three-dimension web like framework will form and the cold flow promoter loses its function.