Method for detecting furnace tube of hydrogen production furnace

A detection method and technology of furnace tubes, which are applied in measuring devices, using sound waves/ultrasonic waves/infrasonic waves to analyze solids, and using sound waves/ultrasonic waves/infrasonic waves for material analysis, etc., can solve the problems of time-consuming and labor-consuming consumables, coarse crystal grains, Problems such as heterogeneous surfaces can reduce the loss of transmitted acoustic energy, improve detection sensitivity, and reduce reflection loss.

Inactive Publication Date: 2019-05-03
南京驰新科技有限责任公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

When the first method is used for detection, since there is a catalyst in the furnace tube, the catalyst must be unloaded before detection. The detection process is time-consuming, labor-intensive and consumable; Lower, therefore, the economical applicability of the radiographic method is lower
[0005] When the second method is used for detection, since the base material of the furnace tube is formed by a combination of equiaxed crystals and columnar crystals, there are defects such as coarse grains, anisotropy and rough surfaces. In these elastic anisotropic materials, due to the change of acoustic impedance and grain boundary scattering, a large part of the energy is dissipated on the crystal plane, which cannot be detected by existing ultrasonic methods

Method used

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  • Method for detecting furnace tube of hydrogen production furnace
  • Method for detecting furnace tube of hydrogen production furnace
  • Method for detecting furnace tube of hydrogen production furnace

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0061] Penetrating cracks occurred in 4 parent metals in the extension section of the radiant furnace tube for synthetic ammonia hydrogen production in a chemical plant in Liaoning. The furnace tube was in normal operation at that time and had been in operation for about 3 years. The material of the furnace tube is Hp40, the specification is Φ108×12mm, and the total number of furnace tubes is 387. According to the detection method of the present invention, it is found that there are 145 furnace tubes with an inner surface greater than or equal to 0.5mm (depth)×5mm (length) Cracking, the crack starts from the inside and develops outward.

[0062] 2 cracked furnace tubes were arbitrarily selected from 145 cracked furnace tubes, and dissected by Party A's testing company. The dissected crack positions and sizes were completely consistent with the detection results obtained by the detection method of the present invention. 145 cracked furnace tubes were replaced, reducing losses a...

Embodiment 2

[0064] Radiation furnace tube inspection for synthetic ammonia hydrogen production in a chemical plant in Xinjiang. The material of the furnace tube is HP40Nb, the specification is Φ171×9mm, and the total number of furnace tubes is 88. The furnace tube is operating normally, which is a normal maintenance test. After inspection, it was found that two furnace tubes had cracks at 1 / 3 of the bottom of the furnace tubes, and the crack depth was between 4 and 5 mm. The reason for the cracks was induced from the inside, and gradually expanded to the outside, and finally cracks appeared. At the same time, the remaining service life of the furnace tube was evaluated.

Embodiment 3

[0066] A reformer tube in a petrochemical company in Tianjin is made of HP40Nb, and the tube specification is Φ186×15mm. After one year of use, a weak basket flame was found outside the lower part of one furnace tube. After testing, it was found that seven furnace tubes were almost in the At the same elevation position, cracks with a length ranging from 6 to 7.5mm appeared. The cause of the cracks is presumed to be from the mechanically damaged pits on the outer surface of the furnace tube. The plasticity of the furnace tube material decreases and becomes brittle.

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Abstract

The invention discloses a method for detecting a furnace tube of a hydrogen production furnace. The method comprises steps that (1), formulating a comparison table of the artificial crack depth and the amplitude of a sound wave signal; (2), removing the dust and dirt on a surface of the furnace tube; (3), adjusting the detection equipment and controlling the flow rate of the water; (4), opening awater valve to adjust the sound wave signal; (5), performing motion detection; and (6), recording waveforms. Based on the comparison table, the damage degree of the furnace tube is rated, as receiving/transmitting probes have low frequency and long wavelength, the penetrating power is strong, moreover, the two probes cooperate with each other, the loss of transmitted sound energy is greatly reduced, detection sensitivity is significantly improved, the water is used as a coupling agent filled between a special tile and a wall of the furnace tube, so the air content between the receiving/transmitting probes and the outer wall of the tube is greatly reduced, improvement of the transmission stability of the receiving/transmitting probes for the acoustic signal is facilitated, and thereby accuracy of the test result is guaranteed.

Description

technical field [0001] The invention relates to metal crack detection, in particular to a detection method for a hydrogen production furnace tube. Background technique [0002] Hydrogen furnace is one of the important equipment in oil refining and fertilizer plant. The base material of the hydrogen production furnace tube is ZGCr25Ni35Nb-(Ti), which is usually made by centrifugal casting. In the process of forming the furnace tube, it is easy to cause defects such as coarse and uneven crystal grains inside the furnace tube and uneven surfaces. The operating temperature of the furnace tube is about 900 degrees. During use, the base material of the furnace tube is prone to creep cracks. With the prolongation of the use time, the cracks will continue to expand. When the cracks expand to a certain depth, the furnace tube will burst and fail. . [0003] After the furnace tube of the hydrogen production furnace is in service, creep cracks will appear on the inner wall of the fu...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N29/11G01N29/265G01N29/28G01N29/24G01N29/22
Inventor 左立超左新民余金秀刘安平余小建黄刚
Owner 南京驰新科技有限责任公司
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