Energy loss analysis of the storage tank coil heating process in a dynamic thermal environment

Abstract

Abstract With the increasing demand for crude oil reserves, storage tanks are being developed on a large scale, and heating energy consumption is gradually increasing. Hence, it is necessary to study energy utilization. The variable physical parameters of crude oil and dynamic thermal environment are considered to establish a coil heating theoretical model of a large crude oil storage tank. On this basis, according to the first and second laws of thermodynamics, the energy loss mechanism of the multiple links in the heating process is analysed. Moreover, the energy consumption evaluation index of the storage tank heating process is established, and the energy consumption mechanism accounting for the tank oil level, the coil heat flow density and the external environmental conditions for the heating process with different coil structures is proposed. The results reveal that the energy loss is affected by the external solar radiation and the dynamic change in the atmospheric temperature, which exhibits fluctuating and rising trends. The external heat loss discharged to the environment through heat dissipation is far lower than the internal heat loss of the tank. Among the different coil structures, an integral large vortex structure is formed for a serpentine coil, with the bottom coil acting as the power element. This large-scale vortex structure obtains energy from time-averaged flow through turbulent shear, which promotes the heat transfer process of natural convection. Additionally, each coil provides a certain buoyancy to the crude oil, and the heat absorption of the crude oil accelerates; thus, the crude oil has a high and stable effective energy utilization degree.