Control of receiving velocity during pigging for Ji-Zi Natural Gas Pipeline

In order to reasonably control the receiving velocity during the pigging of Ji-Zi Natural Gas Pipeline, secondary pig catching and receiving flowrate adjusting are respectively adopted on the basis of accurate calculation of the traveling velocity of the pigging device, thereby avoiding the risk that the pigging device hits the blind plate. According to the SY/T 5922-2003 Operation Criteria of Natural Gas Pipeline, the traveling velocity of pig is assumed to be the same as the flowrate of natural gas, and the traveling velocity calculation formula is thereafter derived. The maximum deviation between the actual traveling velocity and the calculated traveling velocity based on the formula is less than 6%. Comprehensive analysis data from the pig receiving velocity in 16 turnarounds in the Ji-Zi Gas Pipeline shows that when the mass of pig becomes larger, the receiving flowrate will get larger, and the distance between the receiving blind plate and the position where the pig is received will get closer, and the risk that the pig hits the blind plate will get higher. The research result and practical experience provide a basis to the control of pig's traveling velocity.