Abstract:

The crude gas from underground coal gasification (UCG) containing sulfide has the corrosive effects to the steel borehole casing and gas transmitting pipeline before the purification system, which will influence the long-term safe and stable operation of UCG station. To solve this problem, an assumption that replacing the cement pipe with the steel tube is proposed, and the application of concrete pipe in the UCG project is discussed in this paper. We analyzed the stress state of the producing well casing, designed the structure of the cement pipe, and contrasted the cost of steel tube with that of cement pipeline. The results show that the pipeline made by the heat-resistant cement could satisfy the requirements of the UCG project, and has obvious advantages, compared with the steel tube, because of the corrosion resistance and only 1/3 cost of the later.

Key words: underground coal gasification (UCG), borehole casing, gas transmitting pipeline, steel tube, concrete pipe