| The sewage settling tank is an important settling equipment in the oil field for the treatment of oily wastewater.The heat tracing coil is an important component of the settling tank,and under low temperature,corrosion and other conditions,the heat transfer efficiency of the coil decreases and may deform and damage,directly affecting the effectiveness of sewage treatment.This article conducts research on the operation process analysis of sewage settling tanks,heat transfer calculation of settling tanks under solar radiation,strength analysis of multiphase coupling structure of heat tracing coils,and optimization and support improvement of coil structures based on high heat transfer and low stress.It has full academic value and engineering application prospects.Following the principle of going from shallow to deep,the following research work is carried out:1.Taking a sewage settling tank as the research object,the process of settling and collecting oil inside the tank was analyzed,and the thermal motion of the settling tank was explained accordingly.Based on the ASHRAE clear sky model,a calculation method for tank temperature under solar radiation was obtained.By using thermodynamic calculation formulas,the transient heat transfer of coils and the steady-state heat transfer of settling tanks were explained,and a comprehensive heat transfer calculation method combining steady-state and transient was established.At the same time,the external loads on the coil during the settling oil collection process were analyzed,and a multiphase coupling load transfer calculation method for the coil structure was obtained.2.In response to the temperature field distribution problem inside the sewage settling tank under solar radiation,the structural design and material process parameters of the sewage settling tank and three sets of different structural forms of heat tracing coils were introduced.A multiphase coupled numerical model was established for the flow field outside the tank-settling tank-inside the tank and the flow field outside the pipe-coil-inside the pipe under solar radiation.By establishing a finite element model to analyze the temperature field of the settlement oil collection process in different months of a coil structure,the effect of different solar radiation on the heat transfer efficiency of the settlement tank was obtained.3.An analysis was conducted on the stress state and additional load of the heat tracing coil during the settling oil recovery process.A multiphase coupling numerical model of the coil was established considering the weld structure.According to JB4732 "Steel Pressure Vessels-Analysis and Design Standards",a method for evaluating the thermal stress intensity of the coil structure was obtained.Conduct thermal coupling calculations on a type of heat tracing coil in different months,evaluate the structural strength of the coil,and analyze the impact of different solar radiation on the structural strength of the heat tracing coil.4.Comparing the temperature field and structural strength calculation results of different structural forms of heat tracing coils,analyzing the influence of heat tracing coil structural forms on heat transfer efficiency and structural strength,the differences in heat transfer efficiency and structural strength of different structural forms of heat tracing coils were obtained.Among them,the structural two forms of coils were superior to the other coils in terms of heat transfer efficiency and structural strength.Based on the principle of high heat transfer and low stress,from the perspective of improving the support and fixation method of the coil structure,the structural strength of the second form coil is improved,and the operating life of the heat tracing coil is improved.The research results in this paper can provide some reference for improving the heat transfer efficiency of heat tracing coil and ensuring the oil collection effect of sewage settling tank. |
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