Research On Enhanced Heat Transfer Mechanism Of Open Rack Vaporizer Novel Heat Transfer Tube

In recent years,with the increase in energy demand in China,crude oil as a primary energy accounted for a large proportion in our country's energy structure.In the production and transportation links,crude oil has a large storage capacity,at the same time,due to the characteristics of crude oil produced in China and the improvement of the delivery process,lead to the storage time of the crude oil increases and need to heat it to maintain the temperature.In this way,the temperature difference between the crude oil stored in the floating roof tank and the ambient temperature increases,heat loss seriously,resulting in unnecessary energy waste and increase the production cost.Based on this,the heat transfer law of floating roof tank during the storage of crude oil was studied.In this paper,the 20000m3 crude oil floating roof tank in the combined-station of oil collecting and transporting was taken as the research object,and based on the theory of heat transfer,the temperature drop process of the crude oil floating roof tank to the external environment was analyzed,including the change of physical properties of crude oil with temperature drop and the mechanism of wax deposition.Based on the structure of the floating roof tank,considering the influence of the bottom soil on the heat dissipation,and made a certain simplification,used ANSYS ICEM CFD to establish a three-dimensional model of the same size as the actual floating roof tank.Using the physical parameters of crude oil with temperature change,considering the latent heat release of wax in the process of crude oil temperature drop,and the numerical solution was carried out by FLUENT.It is concluded that the crude oil had undergone three phases: a rapid temperature drop,low temperature drop rate,and a low temperature drop,meanwhile,analyzed the temperature and velocity variations of crude oil at each stage.The paper simulated the floating roof tank with different reserves and floating roof insulation measures,and made clear the influence of the reserves and the floating roof insulation factors on the crude oil temperature drop.The idea of increasing the top heater and local heating was proposed to realize the crude oil to storage in the daily low temperature,the main heater was used in the sending and receiving oil,and rapid and local heating up can reduce the heat waste during crude oil storage.Through the study on the temperature drop of crude oil floating roof tank,and improved the oil storage of floating roof tank,it is of great significance to reduce the waste of heat energy during crude oil storing and to realize safe and economical operation of crude oil floating roof tank.