Method of computing the maximum flow stoppage time of buried oil pipelines

摘要

Pipeline breakages are a cause of oil spills and the shutdown time of a pipeline is critical. In this paper, we provide a method for computing both oil temperature and the maximum flow stoppage time of buried pipelines, so that they can restart normally. The most important factor is the simulation of the reduction in the oil's temperature over time. By establishing the location where the oil congeals first, a modified rectangular stable heat transfer physical model and the corresponding mathematical models were developed. In this model, we account for influences from the constant temperature of the earth's layer and soil thermal physical properties (thermal conductivity, temperature diffusivity etc.) that were accurately tested. From this, finite differential software was programmed. We have proven the model and software are effective, from the results of simulated tests. Then, the finite differential software was used to simulate the changes in both the temperature field of the soil, and the oil temperature over time. We calculated the maximum flow stoppage time of the pipeline from Daqing to Harbin by own software. It is concluded that the maximum flow stoppage time of pipeline, before restarting, can be computed precisely with a modified rectangular unstable heat transfer model.