| Natural gas is a clean,high-calorific value fossil energy,and strengthening its development and utilization has become a necessary choice to improve my country’s energy structure and achieve"carbon peaking"and"carbon neutrality"in an orderly manner.In the process of natural gas extraction,gathering,and transportation,the precipitation of liquid water can easily lead to safety problems such as equipment damage,formation of hydrates to block pipelines,and aggravation of equipment corrosion.For this reason,natural gas needs to be dehydrated.Triethylene glycol(TEG)absorption towers are commonly used in traditional natural gas dehydration processes,which have problems such as large size,heavy weight,and low mass transfer efficiency.The application in offshore platforms and remote onshore oil and gas fields is greatly limited.Dropletization is used to strengthen gas-liquid mass transfer,and at the same time,the tubular structure is used to realize the compactness of the TEG absorption and separation equipment.The corresponding core components include a tubular gas-liquid atomizing mixer and a tubular gas-liquid separator.In this paper,the combination of experimental test and computational fluid dynamics(CFD)numerical simulation method is used to study the liquid jet atomization mixing mechanism in the tubular gas-liquid atomizing mixer and the liquid film flow characteristics in the tubular gas-liquid separator.And the overall working characteristics of the tubular natural gas dehydration equipment under different operating parameters.Preliminary research has proved that the use of a venturi flow channel combined with a central bluff body is an effective design method for tubular gas-liquid atomizing mixers.The use of a diamond-shaped cone structure in the square tube can effectively guide the acceleration of airflow,and the use of a boss structure can increase the degree of gas-liquid turbulence.When the gas flow increased from 140 m~3/h to 220 m~3/h,the particle size decreased by 46%,and the atomization concentration increased by 1.7 times;the liquid-gas ratio had a significant effect on the penetration depth of the liquid jet.When TEG was used as the liquid medium,the atomization pressure drop increased compared with water,and the droplet Sauter mean diameter(SMD)decreased.For the gas-liquid atomizing mixer with a circular tubular structure,the circular truncated guide structure plays the role of guiding the airflow to accelerate and promoting the uniform dispersion of droplets,and the atomization and mixing performance is the best,the atomization efficiency can reach 84.4%.When the gas volume is between 70 and 162 m~3/h,the particle size distribution of different diversion structures is 35 to 127μm,air volume from 80 m~3/h to 180 m~3/h,particle size has reduced by 54.5%.For the tubular gas-liquid separator,the morphological change of the liquid film in the gas-liquid cyclone separation pipe section is an important factor affecting the gas-liquid separation performance.However,both high gas volume and high liquid volume conditions will cause the liquid to enter the gas collecting pipe and reduce the separation rate.efficiency.Due to the high viscosity of TEG,it is difficult for the originally designed tubular gas-liquid separator to separate TEG from gas in time.The collection can better solve the problem that high-viscosity fluids are not easy to separate,and the separation efficiency has increased from 20%to 80%before the improvement to more than 90%,successfully realizing the efficient separation of gas and liquid.At the end of the paper,experiments were conducted to explore the influence of different operating parameters on the overall working characteristics of the tubular natural gas dehydration equipment.It was found that the concentration of TEG has a decisive influence on the dehydration effect,and the higher the concentration,the greater the driving force for mass transfer;since the gas flow will directly change the gas-liquid atomization mixing performance,it will have an important impact on the dehydration effect.The liquid-gas ratio and the length of the mass transfer section have little effect on the dehydration effect,but the effect of a high liquid-gas ratio on the dehydration effect is still obvious when the concentration of TEG is large;The mixing and diffusion effect of liquid atomization should generally not be less than 0.7 m.In general,when dehydration is carried out with lean TEG solution under better working conditions,the gas dew point drop after dehydration can reach about 15°C,and the dehydration performance is good.This paper focuses on a series of studies on the dehydration performance of the tubular gas-liquid atomizing mixer,the tubular gas-liquid separator,and the two in series grading operations,which provides reliable data support for the independent research and development of the tubular natural gas dehydration equipment,and promotes the field industrialization.The test application has laid a solid foundation. |
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