Horizontal vessels on fixed supports used for storing high-temperature liquid: An experimental validation of finite element modelling

Abstract

Horizontal cylindrical storage vessels are normally supported on two saddles. When used for storing high-temperature fluid, high values of thermal stress can be avoided by providing one of the supports with a sliding base. However, this ideal may be difficult to achieve in practice and vessels are sometimes found where both saddles have become rigidly fixed to the foundation. In view of this there may be certain advantages in dispensing with the concept of a sliding saddle support altogether and installing the vessels with both saddles permanently fixed to the foundation. Where this is adopted, the vessels and saddles must be designed to carry the thermal stresses that arise from the imposed restraint of the saddle base. Since this procedure is outside normal practice, as set out in the existing pressure vessel codes and standards, it is necessary to undertake detailed analytical investigations, say, using finite element analysis (FEA), to establish the behaviour of the vessels when this approach is used. In order to validate the predictions of temperature and stress obtained from the FEA used in the investigations, it was considered important to carry out some experimental work. This paper reports the techniques used and describes two experimental procedures which were performed on vessels mounted on two quite different saddle designs, both of which are widely used in industry.