Analysis Of Influence Of Saddle Setting On The Cylinder Stress Of Large Horizontal Vessels

Saddle support is one of the most commonly used forms in the design of horizontal vessels. With the development of petrochemical industry, horizontal cylinder vessels tend to be larger and traditional two saddle supports have been unable to satisfy the design requirements, therefore the form of multi-saddles is increasingly being used. But its design calculation is more complex and the previous literature that studies the horizontal vessel supported on multi-saddles mostly uses the Zick method. But when to use multi-saddles and the influence of saddle position on the stress distribution in cylinders are not studied in depth. For these problems, the main works by using the finite element method and theoretical formulas are carried out as follows:1. With regard to the molecular sieve adsorber of Hangyang, considering the working condition of adsorption and regenerative heating, the finite element analysis of adsorber with different saddle setting is performed. Also strength assessment and fatigue strength checking are peformed. By compraing the cylinder stress and deformation distribution in vessel supported on two saddles with that in vessel supported on three saddles, we find that it is not necessary to set the middle saddle.2. The paper studies the two design methods of horizontal cylinder vessel supported on multi-saddles. By eatablishing many horizontal vessel models, compare the minimum wall thickness designed by Zick method with that designed by standard EN13445. It is found that Zick method is more conservative when slenderness ratio is small, and it provides a reference for the selection of design methods of horizontal cylinder vessel supported on multi-saddles.3. For the horizontal vessels with a constant volume, the paper studies the selection of quantity and position of saddles when the cylinders have different slenderness ratio. Based on the vessel volume as a constant value and slenderness ratio as a variable, the paper establishes a series of horizontal vessel models refer to standard JB/T4712. When these models are supported on two saddles. the paper compares the maximum circumferential stress of cylinder at the corner of saddles whose position are A=0.5Ri with that at the corner of saddles whose position are A=0.2L and concludes that the saddle position should be A=0.5Ri as the slenderness ratio less than30. When these models are supported on three saddles, the result that the saddle position should be A=0.5Ri as the slenderness ratio less than13is given. Then by comparing the maximum circumferential stress of vessels supported on two or three saddles, it is concluded that a vessel should be supported on three saddles when slenderness ratio is more than22to26. Finally the optimal slenderness ratio in the design of horizonal vessel is given. The above conclusions have certain engineering practical value, and provide a reference for the designers.