Large-fall liquefied petroleum gas pipeline pressure protection system and method

Abstract

The invention discloses a large-fall liquefied petroleum gas pipeline pressure protection system and method. The system comprises an external transmitting pump system, an upstream remote pressure protection system, an independent parameter monitoring system, a logic control system and the like; and liquefied petroleum gas enters the external transmitting pump system through an in-station storage tank, is pressurized to be conveyed to a downstream station yard through a liquefied petroleum gas pipeline and is received by a storage tank. The trend of a line pipeline is characterized in that a starting point is high, the middle part is low, and an end point is slightly high. Pipeline low point parameters are collected and uploaded by an online low point parameter detection system, are analyzed by a logic control system, and are subjected to protection operation by an upstream remote pressure protection system. According to the large-fall liquefied petroleum gas pipeline pressure protection system and method, an operation process of upstream in-station remote pressure control is adopted in a large-fall liquefied petroleum gas pipeline, a method combining a preset estimated value and anactually-measured value is used in an assisted manner, the extreme condition pressure of the middle and far end large-fall section pipeline is reasonably controlled, and the pipeline low-point pressure protection station yard investment and operation and maintenance personnel expenses are saved.

Description

technical field [0001] The invention relates to a pressure protection system and method for a liquefied petroleum gas pipeline with a large drop. Background technique [0002] In recent years, with the rapid development of natural gas processing and treatment technology, liquefied petroleum gas is an important by-product of natural gas hydrocarbon liquid recovery, and the demand for long-distance pipeline transportation continues to increase. Liquefied petroleum gas has the characteristics of high octane number, good anti-knock performance, and high calorific value. However, because its density is lighter than water in liquid and heavier than air in gas, and it is extremely volatile, once a pipeline leaks, it will inevitably occur. Liquid phase gasification and gas accumulation can easily lead to major accidents. Therefore, the safety protection of LPG pipelines is very important. [0003] Liquefied petroleum gas not only has the characteristics of static pressure differen...

AI Technical Summary

Problems solved by technology

In the high-drop liquefied petroleum gas pipeline, when the pipeline is in normal operation, the operating pressure in the high-drop section is lower than the starting point pressure, and the highest pressure of the system generally appears at the outlet of the outgoing pump at the starting point, and the outgoing pump is equipped with an overpressure protection circuit; After the downstream valve is accidentally closed, for the low-altitude "U"-shaped section close to the downstream of the line, if the outbound pump is not closed in time or cannot be closed due to control problems, it may cause the outbound pump to fill the closed pipeline, and the pipeline The system will quickly establish a hydrostatic pressure system based on the highest discharge pressure of the external pump. The pressure of the "U"-shaped bottom pipeline is equal to the hydrostatic pressure plus the highest discharge pressure at the starting point, which may increase abnormally in a short period of time, even exceeding the strength of the pipeline itself, causing serious security risks

At the same time, for this working condition, if the pipeline pressure relief measures are set at the low point position, equipment and personnel operations need to be considered, which will bring higher investment in equipment and operation, and will also increase the risk of pipeline safety protection. Difficulty; if a thick-walled pipe with a higher design pressure is selected in the low point section, it may cause a substantial increase in investment and may have an impact on pipeline pigging

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