Regarding the material of the equipment
Thread Content
The design pressure of the liquid separation tank at the inlet of the cyclohydrogen desulfurization tower in a gasoline hydrogenation unit is 2.3 MPa, with a design temperature of 170 degrees. If Q245R is used, the calculated thickness is 21.6 mm; considering a corrosion allowance of 6 mm, the nominal thickness would be 30 mm. I would like to ask fellow engineers whether it is possible to use Q345R in order to reduce the wall thickness. In an environment subject to wet hydrogen sulfide corrosion, which material is better – Q245R or Q345R?
If wet hydrogen sulfide corrosion is severe, use Q345R resistant to HIC. If it’s not severe, Q245R is recommended in SH/T3096.
I have another question: Is 30mm of Q245R a bit thick? SH/T3075 recommends the use of carbon steel for thicknesses below 8mm, and low-alloy steel for thicker sections
It is indeed quite thick. After calculating the overall cost, if using Q345R with HIC resistance proves to be cheaper, then that’s the material to be used.
The main considerations for material selection are currently two: the actual needs on site and cost control. Considering the actual situation, steel prices are currently slightly low; it is recommended to choose higher-quality materials.
Choose Q345R-HIC. All high-pressure hydrogenation units use this.
It is highly unreasonable to choose 30mm Q245R for such equipment; no one does that.
Under normal conditions, how thick can Q245R steel plates be used?
The last edit to this post was made by svenzheng on 2016-8-18 at 07:27; there are 16 layers with decreasing thicknesses, and contractors using Q245R material and 30 layers of material for welding the tanks will go crazy；