Characteristics of flow and liquid distribution in a gas–liquid vortex separator with multi spiral arms--颗粒学报PARTICUOLOGY

Yao, X., Zuo, P., Lu, C., E, C., & Liu, M. (2022). Characteristics of flow and liquid distribution in a gas–liquid vortex separator with multi spiral arms. Particuology, 68, 101-113. https://doi.org/10.1016/j.partic.2021.11.008

Characteristics of flow and liquid distribution in a gas–liquid vortex separator with multi spiral arms

Xiuying Yao ^a, Peng Zuo ^{a b}, Chunxi Lu ^a *, Chenglin E ^a, Mengxi Liu ^a

a State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing 102249, China
b Research Institute of Experimental and Detection, Xinjiang Oilfield Company, PetroChina, Karamay, Xinjiang 834000, China

10.1016/j.partic.2021.11.008

Volume 68, September 2022, Pages 101-113

Received 2 September 2021, Revised 12 November 2021, Accepted 18 November 2021, Available online 29 November 2021, Version of Record 20 December 2021.

E-mail: lcx725@sina.com

Highlights

• Separation efficiency is influenced by flow field and liquid phase concentration.

• The transverse vortex entrains the small droplets into the upper annulus zone.

• Higher liquid phase concentration in the top liquid ring reduces the efficiency.

• The annular zone height affects the efficiency but does not affect the pressure drop.

• The annular zone height of 940 mm is the most economical.

Abstract

Fischer–Tropsch (F–T) synthesis is an important route to achieve the clean fuel production. The performance of gas–liquid separation equipment involving in the progressive condensation and separation of light and heavy hydrocarbons in the oil-gas products has become a bottleneck restricting the smooth operation of the F–T process. In order to remove the bottleneck, a gas–liquid vortex separator with simple structure, low pressure drop and big separation capacity was designed to achieve the efficient separation between gas and droplets for a long period. The RSM (Reynolds Stress Model) and DPM (Discrete Phase Method) are employed to simulate the flow characteristics and liquid distribution in the separator. The results show that the separation efficiency is influenced by the flow field and liquid phase concentration in the annular zone. The transverse vortex at the top of spiral arm entrains the droplets with small diameter into the upper annular zone. The entrained droplets rotate upward at an angle of about 37.4°. The screw pitch between neighbor liquid threads is about 0.3 m. There is a top liquid ring in the top of annular zone, where the higher is the liquid phase concentration, the lower is the separation efficiency. It is found that by changing the operating condition and the annular zone height the vortex can be strengthened but not enlarged by the inlet velocity. The screw pitch is not affected by both inlet velocity and annular zone height. The liquid phase concentration in the top liquid ring decreases with both the increases of inlet velocity and annular zone height. The total pressure drop is almost not affected by the annular zone height but is obviously affected by the inlet velocity. When the height of annular zone is more than 940 mm, the separation efficiency is not changed. Therefore, the annular zone height of 940 mm is thought to be the most economical design.

Graphical abstract

Keywords

Gas–liquid separator; Vortex separation; Structural optimization; Separation performance; Computational fluid dynamics

文章导读