About jacketed vessel calculations
Thread Content
This post was last edited by yechao25038 on 2019-2-21 12:11 1. The corrosion margin of the inner cylinder is 3, the corrosion margin of the jacket is 1.5, and the corrosion margin of 4.5 was selected when calculating the inner cylinder (the corrosion margin has never been considered this way before: L). If the inner cylinder is a composite plate, is it possible to ignore the corrosion of the inner cylinder medium on the base layer of the composite plate? Is it ok to only consider the jacket for the corrosion allowance of the inner cylinder? 2. The design temperature of the inner cylinder is 180℃, and the design temperature of the jacket is 250℃. The calculated design temperature of the inner cylinder is 250°C, which is the higher of the two. Is this reasonable? So what’s the use of the inner cylinder’s design temperature of 180°C? Is it used to calculate the equipment flange in the picture or the upper head that is not covered by a jacket? When judging whether the equipment belongs to a hydrogen corrosive environment, which design temperature should be chosen? (I usually avoid hydrogen corrosive environments by lowering the design temperature, for example, the design temperature is 190°C:L. Occasionally, the design temperature of the jacket is higher than 200°C.) The picture is from the "Pressure Vessel Engineer Design Guide"
1. The corrosion margin of the inner cylinder is 3, the corrosion margin of the jacket is 1.5, and the corrosion margin of the inner cylinder is 4.5 (the corrosion margin has never been considered in this way before). If the inner cylinder is a composite plate, is it possible to ignore the corrosion of the inner cylinder medium on the base layer of the composite plate? Is it ok to only consider the jacket for the corrosion allowance of the inner cylinder? Can! 2. The design temperature of the inner cylinder is 180℃, and the design temperature of the jacket is 250℃. According to the actual temperature of the jacket metal! The calculated design temperature of the inner cylinder is about 180°C, which is 250°C of the jacket, which is the higher of the two. Is this reasonable? So what’s the use of the inner cylinder’s design temperature of 180°C? Is it used to calculate the equipment flange in the picture or the upper head that is not covered by a jacket? It’s up to each! When judging whether the equipment belongs to a hydrogen corrosive environment, which design temperature should be chosen? (I usually avoid hydrogen corrosive environment by lowering the design temperature, such as the design temperature is 190°C, and occasionally the design temperature of the jacket is higher than 200°C)
In this example, the calculated design temperature of the cylinder is 250°C, which is the higher of the two. Is it reasonable?
I think that in the design of jacketed equipment, it is more reasonable to take the design temperature as the maximum achievable value of 250°C. This seems to be somewhat different from the calculation of heat exchangers.
The design temperature is the average temperature of the metal cross-section. Taking the design temperature of the jacket directly in the calculation is a conservative approach and cannot be said to be unreasonable. The design temperature of the unjacketed part is still 180 degrees.
This leaves only one upper head, and finally the hydraulic test pressure must be considered comprehensively.
Take according to GB/150. Pay special attention to the temperature when verifying the hydrostatic test, selecting materials, and selecting flanges. 180 degrees Celsius is also available, where required by the design of non-jacketed parts.
Understood. Ignoring the most basic definition of design temperature: lol
This post was last edited by yechao25038 on 2019-1-19 07:27 Yes. Regarding the allowable stress of the material at the "design temperature" in the hydraulic test formula, should the design temperature be 180°C, because the minimum value of the pressure test pressure calculated for each pressure-bearing component should be selected for the pressure test?