The state of the art of longdistance gas pipeline in China

The state of the art of long distance gas pipeline of China was reviewed in this paper. With the urgent demand of clean energy for economy growth and reduction of air pollution, more and more pipeline projects had been completed and have been launching in the past decades. Aiming at greatly increasing efficiency and saving budget, higher strength and larger-diameter pipes have been developed and applied for constructing long distance pipeline projects in China. For example, X80 grade pipeline has been applied to the 2nd west to east gas pipeline (2nd WEGP) with a distance of 7,000 km. This is the longest pipeline built by X80 pipeline steel in the world. Comparing with the first west to east gas pipeline(1st WEGP) built by X70 , the diameter increased from 1,016 mm to 1,219 mm, wall thickness from 14.6 mm to 18.4 mm, gas pressure from 10 MPa to 12 MPa, the transmission capacity increased from 17 bm3/a to 30 bm3/a. Taking account of the steel amount, construction cost and other market reason (almost 95 % was supplied by domestic steel companies), the investment of the 2nd WEGP is almost as same as the 1st WEGP. Moreover, other long distance pipeline projects are introduced in this paper, and the technology achievement for developing X80 pipe is also presented.