Pipeline non-stop control technology:

The intelligent core ensuring the continuous operation of energy arteries In the field of energy transportation, the on-line control technology for pipelines without shutdown is changing the traditional operation and maintenance mode of pipelines with its unique technical charm, and has become the key to ensuring the continuous operation of the country's energy arteries. In modern industrial society, energy pipelines are like the vascular network of the human body, carrying the flow of a nation's economic lifeline. Once the supply is interrupted, it will not only cause huge economic losses but also affect social production and residents' lives. Pipeline non-stop control technology emerged under such circumstances. It enables pipelines to carry out maintenance, renovation and inspection operations without interrupting the transportation, thus becoming an important technical means to ensure energy security. 01 Technical Principle: The Intelligent Fusion of Two Control Theories The fundamental theories of pipeline non-stop control technology can be traced back to two different control concepts: control by throughput and control by strength. These two theories each have their own characteristics in the operation of long-distance pipelines and together form the theoretical foundation of non-stop technology. Flow control based on input volume is a traditional control method. Each pumping station sets the inlet pressure and the outlet pressure is formed naturally. This method is simple to operate, but it has obvious limitations - generally, only a conservative flow rate with a relatively low value can be set for the pipeline. When an intermediate pumping station stops abnormally, flow control based on input volume can only end in loss of control. In contrast, pressure control based on intensity demonstrates greater technical advantages. Under this control mode, each pumping station sets the discharge pressure, and the suction pressure is formed naturally. Controlling by intensity not only can avoid calculation errors, but more importantly, it can make correct and reasonable responses and treatments to water hammer and sequential transportation processes, which can enable the pipeline to achieve the maximum flow. When an intermediate pumping station abnormally shuts down, the intensity control can automatically guide the pipeline to the bypassing transportation state to ensure the continuity of transportation. This adaptive feature makes it an ideal choice for uninterrupted control. In modern pipeline control, these two theories are often wisely integrated and applied. Through advanced control systems and real-time monitoring devices, pipeline operators can dynamically adjust control strategies based on actual conditions to achieve the optimal balance between throughput and intensity. 02 Technological Evolution: The Transformation from Traditional Operations to Modern Processes Pipeline non-stop transportation technology has undergone an evolution from simple to complex and from mechanical to intelligent. In the early days, most pipeline operations were carried out by stopping the transportation, which required a series of complex procedures such as emptying the pipe section and conducting gas detection, which was time-consuming, labor-intensive and had safety risks. With the advancement of technology, the technology of opening holes and blocking without pipeline shutdown has gradually matured. This technology involves performing operations such as opening holes and blocking on the target pipeline while it is under pressure, and at the same time, establishing a bypass pipeline to enable the connection of the new and old pipelines. Compared with traditional shutdown operations, the non-stop transmission technology has significant advantages: the hole opening is carried out in a fully sealed state, with no oil and gas leakage, the original equipment can operate normally, and the operation time is significantly shortened. The non-stop blocking technologies represented by airbag blocking, disc blocking and bucket blocking have been continuously developed and improved, adapting to different pressure, pipe diameter and medium conditions. The disc plugging process involves using a hole opener to cut a saddle-shaped hole in the gas transmission pipeline. Then, a plugging device is employed to push a high-molecular rubber cup into the pipeline through hydraulic transmission and a crank connecting rod mechanism to block the gas source. The bucket plugging process involves completely cutting off the target pipeline, then using a plugging device to send an expandable bucket along the cut hole to the central position of the gas transmission pipeline. The bucket expands through the transmission device of the plugging device itself, thereby blocking the gas source. These two techniques each have their applicable scenarios and together form the technical system of non-stop blockage. 03 Key Technologies: Precision Operations under Complex Working Conditions Pipeline non-stop control technology involves a series of key technical links, each of which requires precise control and strict management. The opening and blocking operation is the core of the entire technology, and its operational accuracy directly affects the success or failure of the project. During the renovation project of the Aseyi Line, technicians connected the new and old pipelines to the station equipment respectively by building temporary processes, ensuring that both pipelines could operate simultaneously. This approach enabled the complete replacement of the old pipeline with the new one without interrupting the transportation. This successful case demonstrates the application value of non-stop transmission technology in pipeline replacement. Quality control is the lifeline of non-stop operation. From pre-operation control, operation process control to operation recovery, there are strict quality requirements for each link. Before the operation, a site survey is required to confirm that the straight welds of the pipeline are not directly above the pipeline to avoid affecting the hole opening operation. At the same time, the inclination angle of the pipeline should be fully measured to facilitate the data measurement and calculation as well as operation control for the angled hole opening and blocking operation. Three-way welding is a crucial process in non-stop operation. The installation spacing of the three-way must be precisely positioned in strict accordance with the standard requirements. The actual wall thickness of the pipe at the position of the three-way's circumferential weld seam should be measured, and the welding position should be recalculated and confirmed based on the allowable welding pressure calculation formula provided by the standard. The welding process must strictly follow the welding procedure specifications, implement requirements such as preheating, multiple passes and layers, and single-layer welding thickness, to ensure welding quality. During the hole opening operation, it is necessary to check whether the installation positions of the center drill and the tube cutter are perpendicular to the centerline of the pipeline, measure and calculate the dimensions, and record them. During the hole opening process, the matching of the rotational speed and feed rate should be comprehensively judged through the equipment operation procedures and the cutting sound to ensure the quality of the hole opening. After the hole opening is completed, it is necessary to check immediately whether the saddle-shaped plate has been removed and to inspect the wear of the center drill and the cylinder cutter. 04 Application fields: Extensive coverage from oil and gas to urban gas The application field of pipeline non-stop control technology has expanded from the initial oil pipeline to various media and working conditions. In the field of oil and gas transportation, non-stop technology has solved the problems of maintenance and renovation of long-distance pipelines.