Separation performance and centrifugal characteristics of a cascade dewatering equipment

Abstract

This paper addresses the escalating challenge of oil–water separation by proposing a novel concept of partitioned and graded cyclone separation. The primary objective is to mitigate the issue of inefficient heating energy consumption in fluids produced with a high water cut, thereby meeting the demands for a low-carbon and energy-saving process. The paper introduces the concepts of split chamber swirl and targeted separation, and designs cascade dewatering equipment to achieve compact and efficient cascade enhanced dewatering performance. The separation performance of the equipment was analyzed through the combination of experiment and numerical simulation. The results reveal that the centrifugal acceleration of the main swirl chamber is 250 times that of gravity, and the centrifugal acceleration of each subsidiary swirl chamber is 5200 times that of gravity. Large oil droplets are separated in the main chamber, while small oil droplets are separated in the subsidiary swirl chamber, realizing efficient oil–water separation. Compared to single-stage dewatering equipment, the dewatering rate of the cascade dewatering equipment increases by approximately 20 %. When the inlet flow rate is controlled at 1.0 m³/h–1.3 m³/h and the inlet water cut ranges from 70 % to 85 %, the dewatering rate exceeds 70 %, meeting the technical indicators for an oil outlet water cut less than 50 %. Furthermore, by controlling the split ratio within 43 %, the recovery rate of oil can exceed 80 %. It is noteworthy that the cascade dewatering equipment offers a novel solution to the problem of fluids produced with a high water cut.