Open Access

ARTICLE

Title Supersonic Condensation and Separation Characteristics of CO₂-Rich Natural Gas under Different Pressures

Yong Zheng¹, Lei Zhao¹, Yujiang Wang¹, Feng Chang¹, Weijia Dong^2,*, Xinying Liu², Yunfei Li², Xiaohan Zhang², Ziyuan Zhao³
1 Engineering Management Center, Sinopec Shengli Oilfield Company, Dongying, 257000, China
2 Technical Inspection Center, Sinopec Shengli Oilfield Company, Dongying, 257000, China
3 Shandong Provincial Key Laboratory of Oil & Gas Storage and Transportation Safety, College of Pipeline and Civil Engineering, China University of Petroleum, Qingdao, 266580, China
* Corresponding Author: Weijia Dong. Email:
(This article belongs to this Special Issue: Multiphase Flow Theory in Oil and Gas Gathering and Transportation Process)

Energy Engineering 2023, 120(2), 529-540. https://doi.org/10.32604/ee.2023.022765

Received 24 March 2022; Accepted 07 June 2022; Issue published 29 November 2022

Abstract

Supersonic separation technology is a new natural gas sweetening method for the treatment of natural gas with high CO₂ (carbon dioxide) content. The structures of the Laval nozzle and the supersonic separator were designed, and the mathematical models of supersonic condensation and swirling separation for CO₂-CH₄ mixture gas were established. The supersonic condensation characteristics of CO₂ in natural gas and the separation characteristics of condensed droplets under different inlet pressures were studied. The results show that higher inlet pressure results in a larger droplet radius and higher liquid phase mass fraction; additionally, the influence of centrifugal force is more pronounced, and the separation efficiency and removal efficiency of CO₂ are higher. When the inlet pressure is 6 and 9 MPa, the liquefaction efficiency at the Laval nozzle outlet increases from 56.90% to 79.97%, and the outlet droplet radius increases from 0.39 to 0.72 μm, and the removal efficiency is 31.25% and 54.52%, respectively. The effects of inlet pressures on the removal efficiency of the supersonic separator are complicated and are controlled by the combined effects of liquefaction capacity of the nozzle and centrifugal separation capacity of the swirl vane.

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Keywords

Supersonic separator; Laval nozzle; natural gas; carbon dioxide; condensation; separation

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