Open fire maintenance method for liquid ammonia pipeline or equipment

Abstract

Provided is an open fire maintenance method for a liquid ammonia pipeline or equipment. The method is characterized by comprising the following steps that (1), an inlet valve and an outlet valve of the equipment are closed, and a blowoff valve is opened; (2), a short connection pipe is manufactured, and the other end of a valve is connected with inert gas, wherein the inner diameter of the short connection pipe can be determined in the way that the short connection pipe covers a leakage point, and the short connection pipe is connected with the valve; (3), when the pressure of the pipeline or the equipment is close to the atmospheric pressure, the manufactured short connection pipe buckles the leakage point; (4), the inert gas is started to be continuously supplied to the pipeline or the equipment via the short connection pipe, and positive pressure is kept to open fire to weld the short connection pipe and the leakage point; (5), after the short connection pipe and the leakage point are welded, the inert gas continues to blow for a period to cool a welded point; (6), the inert gas is moved off, the valve of the short connection pipe is closed, and flaw detection and leakage test pressure testing are carried out on the welded point; (7), after the welded point passes the flaw detection and leakage test pressure testing, the open fire maintenance is finished. The open fire maintenance method for the liquid ammonia pipeline or equipment is applied to the field of liquid ammonia conveying.

Description

[0001] technical field [0002] The invention relates to the transportation of liquid ammonia, in particular to a hot-fire maintenance method for liquid ammonia pipelines or equipment. Background technique [0003] Liquid ammonia transportation is one of the basic operating units of liquid ammonia production, storage, use, and sales. At present, some liquid ammonia pipelines or equipment leak due to reasons such as long service life and corrosion. Great security risk. Liquid ammonia volatilizes to form ammonia gas. Ammonia gas is a toxic, flammable and explosive gas with an upper limit of 27.0% and a lower limit of 15.5%. The maximum allowable concentration in the workplace is 30mg / m 3 , mixed with air can form an explosive mixture, leakage of substances can lead to poisoning, are irritating to human eyes, mucous membranes or skin or have the risk of burns and frostbite. [0004] The liquid ammonia delivery area is a high-risk area. The maintenance of conventional liquid a...

AI Technical Summary

Problems solved by technology

[0011] The purpose of the present invention is to overcome the defects of the prior art and provide a hot-fire repair method for liquid ammonia pipelines or equipment to solve the complicated repair operation of conventional liquid ammonia delivery devices And it takes a long time and low efficiency technical problems

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