Inspection and crack treatment of the hottest ammo

  • Detail

Inspection and crack treatment of ammonia converter the ammonia converter of a chemical company in Jiaozuo City was manufactured on May 31, 1985 and put into use on October 8, 1988. The tower is multi-layer, and the spacing is adjusted based on the movement of the console to connect the control console end to bind the pressure vessel. The inner diameter is automatically stored: the experimental condition is 600mm, the height is LL 410 mm, and the thickness of the simplified body is 80 mm. It is longitudinally formed by the inner cylinder and 10 layers of binding laminates. The inner cylinder material is 16MnR, the thickness is 20 mm, and the laminate material is SPV36, the thickness is 6 mm. The head is a forging. In 2017, China's box board paper consumption was 25.1 million tons, and the material was 20mnm0. The design pressure is 31.4 MPa, the design temperature is 195 ℃, and the medium is N2, H2, NH, CH4 and blood. The tower internals are catalyst baskets, with a design pressure difference of l.0 MPa and a working temperature of 540. C。 In August, 2010, the equipment was found to have abnormal temperature during operation, so it was shut down for inspection and umbrella inspection

overall inspection overview

1 macro inspection

macro inspection of internal and external wall corrosion and service conditions by day vision or with the help of magnifying glass. Remove the insulation layer during inspection, and pay attention to the internal and external tower walls, internals, welds and connections. Upon inspection, 32 corrosion pits were found on the inner wall of the tower, which were distributed on each cylinder connection, with a maximum of 20 mm × 1nm。 There are also 11 mechanical damages, so the maximum is 400 MMX 30 mmx1 nm. The undercut and misalignment of welded joints on the surface of the tower body were inspected, and it was found that there were many grinding parts on the welded joint surface

2 wall thickness measurement

measure the wall thickness of the inner cylinder, focusing on the corrosion, wear and other parts. Through measurement, the thickness of the inner cylinder is between 19--20.5mm, and the wall thickness is basically normal

3 table non destructive testing

(1) penetrant testing. No defects were found in the penetration spot check of the main bolts

(2) magnetic particle testing. Magnetic particle inspection was carried out for 6 class B welds on the inner cylinder of the ammonia converter and the outer side of the connecting circumferential weld between the lower head and the cylinder

4 ultrasonic testing was carried out for the circumferential weld on the inner wall and the defect parts found in the surface inspection by ultrasonic. It was found that the second cylinder section was about 50mm long and the third cylinder section was about 200mm long, with a buried depth of 5 ~ 10mm, and the other cracks were near surface defects

5 hardness measurement

select the dry points at the defective and non defective parts of the first, second, third and sixth cylinder sections on the inner wall of the tower for hardness measurement: the hardness is between 120 and 202 Hb, which is basically normal

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