Local replacement of desulfurization drill pipes in delayed coking
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Senior colleagues, the lower outer surface of the drill rods in the hydrocracking unit’s coking removal system shows many pitting and small holes due to corrosion (there are basically no signs of corrosion on the upper part of the drill rods). Given the poor quality of the water used for coking removal, there is concern that corrosion may also occur inside the drill rods. Thickness measurement results show a reduction of 2 mm, but a single measurement point cannot guarantee that there is no severe corrosion in other areas. Is it possible to replace only the lower section of the drill rod that is corroded?
This post was last edited by karamay on 2015-9-23 at 15:08. The entire drill pipe isn’t that expensive either; so why not replace it? Changing to another paragraph is of course no problem, but the following issues need to be addressed: 1. If a short segment is purchased, it has to be custom-made, and the cost might be as much as that of a full segment. 2. To achieve welding with proper coaxiality and perpendicularity, heat treatment requires professional personnel. To save money, here’s a random idea: reuse the drill pipes.
I think your idea is good! Has it been applied yet?
This wasn’t downloaded. I lean more towards your first option: just replace it.
There are no drill pipes. But the air-cooled version was replaced; it would corrode and develop holes after 4-5 years, while by flipping it over after 3 years, its lifespan could be extended to 6 years. The tubes are all corroded on the lower half.
What are the difficulties in terms of construction when replacing a drill pipe section? Does replacing the drill pipe with a new one after grinding away the weld result in a weak connection between the old and new drill pipes?
If replacing it, use a new one; consider the manufacturer’s recommendations and don’t just go for the cheapest option
Verticality. Otherwise, the drill pipe will swing as it rotates. But welding causes deformation.
Our drill pipes also have many small spots; their thickness has not been measured yet
It is recommended to replace it with a new one. Otherwise, after replacing some parts, further post-processing is required, which is troublesome; high quality is needed as well, and problems are likely to occur. It’s not cheap either, and it’s not reliable to use