Composite pipeline for transporting hydrogen and method for monitoring hydrogen leakage

A method for real-time whole-pipeline monitoring of a composite pipeline for transporting hydrogen in a hydrogen transport network, the method comprising:

• numbering a plurality of hydrogen sensors sequentially starting from “1” for a first hydrogen sensor at an inlet end of the hydrogen transport network to “n” for a last hydrogen sensor at an outlet end of the hydrogen transport network, each hydrogen sensor corresponding to a measurement point in the composite pipeline, wherein n is an integer and represents a number of the plurality of hydrogen sensors, wherein the plurality of hydrogen sensors are arranged at corresponding joints along the composite pipeline, wherein the composite pipeline comprises a plastic pipe, a polyurethane foam layer, and a plastic protection layer disposed in sequence from inside to outside of the composite pipeline, the plastic pipe comprises a polyethylene material, the polyurethane foam layer comprises mixed and foamed poly diphenylmethane diisocyanate and polyether and has a thickness identical to a half of a difference between an inner diameter of the plastic protection layer and an outer diameter of the plastic pipe, and the plastic protection layer comprises a high-density polyethylene material with a thickness between 4 mm and 10 mm, and wherein an evacuation pipe is installed at a joint between adjacent sections of the composite pipeline, and a corresponding hydrogen sensor is installed inside the evacuation pipe;
• plotting a first coordinate system and a second coordinate system, wherein a vertical axis of the first coordinate system represents a hydrogen concentration and a horizontal axis of the first coordinate system represents time, wherein a vertical axis of the second coordinate system represents a hydrogen concentration and a horizontal axis of the second coordinate system represents each of the plurality of hydrogen sensors, and each number is marked on the coordinate axis in turn in equal proportion according to a pipe length of each section of the composite pipeline, with “1” coinciding with a coordinate origin;
• detecting a change in the hydrogen concentration of each of a plurality of measurement points in the composite pipeline by a corresponding hydrogen sensor inside a corresponding evacuation pipe, and displaying a specific measured value of the hydrogen concentration and an ambient temperature in a signal receiving and processing device, wherein, after the composite pipeline is damaged inside, a leakage of hydrogen at a leak position increases, and more hydrogen enters the polyurethane foam layer;
• and leaked hydrogen collects in the polyurethane foam layer, more hydrogen spreads along the polyurethane foam layer, and more hydrogen diffuses in the evacuation pipe near the leak position, and there are small fluctuations in diffusion of hydrogen in other evacuation pipes;
• outputting the hydrogen concentration of each of the plurality of measurement points in the composite pipeline over a period of time and outputting hydrogen concentrations of the plurality of measurement points in the composite pipeline at a same time;
• establishing a first curve of hydrogen concentration over time based on the hydrogen concentration at different times of a same measurement point, and establishing a second curve of hydrogen concentration in an overall of the composite pipeline based on the hydrogen concentrations at the plurality of measurement points in the composite pipeline at the same time;
• and
• determining whether there is a leakage according to a jump of the first curve and the second curve, and in response to determining that there is a leakage, outputting an alarm signal, recording a time corresponding to the alarm signal, and determining a specific leak position in the composite pipeline.