Start-up heating furnace coil pipe production method of synthetic ammonia device

Abstract

The invention relates to a start-up heating furnace coil pipe production method of a synthetic ammonia device. The start-up heating furnace coil pipe production method includes welding and installing materials straight pipes one by one, and then processing the welded and installed straight pipes into coil pipes by a spiral coiler. Compared with the existing method of producing single coil pipe and then welding and installing, the start-up heating furnace coil pipe production method of the synthetic ammonia device greatly improves processing quality and working efficiency, and reduces production cost.

Description

technical field [0001] The invention relates to a manufacturing method of a chemical plant, in particular to a manufacturing method of a heating furnace coil of an ammonia synthesis plant. Background technique [0002] In large-scale synthetic ammonia plants with an annual output of 200,000 to 300,000 tons, the start-up heating furnace is a preheating device before the reaction gas enters the synthesis tower at the initial stage of reformer ignition. The heating and reaction of the reaction gas are carried out in the furnace coil. Its characteristics The temperature of the tube wall is high, the pressure inside the tube is high, the design pressure of the furnace tube is 12.025MPa, the design temperature is 565°C, the maximum working pressure at the top is 10.946 MPa, the operating temperature is 445°C, and the process medium is hydrogen and nitrogen, which are flammable and explosive media. The selection of tube material and the manufacturing quality of the coil are of grea...

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Problems solved by technology

[0007] (1) The production of each circle has to go through three processes of coiling, pitch twisting, and butt welding, and the efficiency is very low

[0008] (2) The assembly welding is carried out in a spiral shape, the welding groove cannot be machined, the groove shape is difficult to guarantee, the argon gas protection is difficult, and the welding quality is difficult to guarantee

[0009] (3) When bending the open ring pipe, the material should be cut according to its unfolded length, and the two ports should be cut into oblique openings to bend into an open ring pipe. After twisting into a spiral pipe, the diameter of the coil pipe will be reduced, so the lower It is necessary to leave a margin for the unfolded length during the material, so that the diameter of the open ring pipe is larger than the diameter of the coil, and the welding groove needs to be reprocessed. It is difficult to grasp the length margin, and the diameter and pitch of the coil are difficult to meet the design requirements.

[0010] (4) Due to the low labor productivity of the single-turn plate system and single-turn assembly welding, the labor cost is high, there are many assembly tools, the consumption of argon gas for welding is large, the cost of on-site flaw detection is increased, and the manufacturing cost is high.

[0011] (5) Difficulty in welding repair and flaw detection

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