Study on Energy Flow Characteristics of Solar–Gas Combined Heating System for Settling Tank of Oilfield

Abstract

Heating furnaces fueled by fossil fuels are commonly utilized in oilfields to provide heat to the settling tank, which heats the layer of crude oil. However, this traditional heating method consumes a significant amount of oil and gas resources, resulting in low energy utilization and environmental pollution. As the water content of the extracted crude oil increases over time, the operating costs of the settling tanks also continue to increase. Therefore, it is crucial to develop and implement clean and efficient heating technologies to facilitate the efficient operation of settling tanks. This paper proposes a solar–gas combined heating technology for settling tanks. A simulation model for the solar–gas combined heating system for the settling tank is constructed, considering the overall perspective of the system. The simulation model analyzes the impact of the control strategy for the oil collection period of the settling tank on the system performance. This analysis covers various aspects including the heat collection of the solar collector, the heat supply of the gas boiler, and the heat storage and release of the phase-change heat storage tank. The results demonstrate that when the oil collection cycle is Scheme E (4:00–8:00), the collector achieves the highest annual cumulative heat collection, the gas boiler provides the lowest annual total heat supply, and the phase-change heat storage tank exhibits the highest heat storage and release efficiency. Over the course of the system’s 15 year service life, the settling tank solar–gas combined heating system saves 727,988.69 MJ of energy annually, resulting in total energy-saving costs of CNY 397,007. The dynamic investment payback period is estimated at 9.14 years, and the system reduces CO2 emissions by 753,069.8 kg.