The effect of water content in crude oil on the tribological behavior of screw pump’s stator rubber

It is worthy of studying the effect of water content in crude oil on tribological behavior of stator rubber, because the different water content would affect the swelling and wear of rubber. Compatibility of dewatered crude oil and water was observed after mixture of dewatered crude oil and water （called oilwater mixture） was mechanical stirred and statically placed. Static etching experiment of samples in oil-water mixture was performed using hanging patch test. Wetting contact angle of oil- water mixture on rubber surface was measured by contact angle meter. Tribological behavior of samples in mixture was measured using a ringonblock tester. The result shows that when the water content is less than 15 %, water can blend with dewatered crude oil, and oil-water separation happens when water content was more than 15 %. With the increasing of water content in crude oil, Wettability of mixture and swelling increment of samples decrease. The wear loss of sample increases after treated by swelling experiment, and FKM owns better wear resistance than NBR.