Coal underground gasification continuous pipe and connection method thereof

Abstract

The invention discloses a coal underground gasification continuous pipe and a connection method thereof. The continuous pipe comprises a titanium alloy pipe body and a titanium alloy pipe body, the pipe end of the stainless steel continuous pipe body and the pipe end of the titanium alloy pipe are connected through threads meshing with each other, the portion between the stainless steel continuouspipe body and the titanium alloy pipe body is sealed, and the connecting parts of the stainless steel continuous pipe body and the titanium alloy pipe body are fixed through a countersunk pin in theradial direction. The connection method comprises the steps that the stainless steel continuous pipe body is fixed, the threads on the stainless steel continuous pipe body and on the titanium alloy pipe body are coated with high-temperature locking grease, the titanium alloy pipe body is screwed into the stainless steel continuous pipe body by using a preset make-up torque, then a pin connection threaded hole with a counter bore is drilled between the titanium alloy pipe body and the titanium alloy pipe body in the radial direction, and finally, the countersunk pin is screwed into the pin connection threaded hole. According to the continuous pipe, the titanium alloy pipe body is connected to the front end of the titanium alloy pipe body, so that the high temperature resistance and corrosion resistance of the pipe end of the underground gasification continuous pipe can be improved, and performance requirements of the coal underground gasification process for pipes are met.

Description

technical field [0001] The invention belongs to the field of underground coal gasification and exploitation, and particularly relates to a coiled pipe for underground coal gasification and a connection method thereof. Background technique [0002] Underground coal gasification refers to the creation of appropriate process conditions for deep coal in situ and controlled combustion. Through the pyrolysis of coal and a series of chemical reactions between coal and oxygen and water vapor, hydrogen, carbon monoxide and methane are produced. Chemical gas recovery technology for combustible gases. The progress of coiled tubing controlled retreat gas injection technology has promoted the development of modern underground coal gasification technology. During the retreat and drag of the UGC, the tube is subjected to high-pressure oxygen, and the front end of the tube faces a high temperature and corrosive environment above 250 °C. risk. Existing coiled tubing is mainly made of carb...

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Problems solved by technology

[0003] The purpose of the present invention is to solve the problem that the underground gasification coiled tube in the prior art is prone to failure during the retreating and dragging process, and to provide an underground coal gasification coiled tube and its connection method, in which a section of titanium alloy is connected to the front end of the stainless steel coiled tube Pipe, enhance the resistance to high temperature and corrosion of the pipe end of the underground gasification continuous pipe, and meet the performance requirements of the pipe for the underground coal gasification process

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