Design Methodology for the Support Beams of Internal Beds in Vertical Vessels

Abstract

In the Petro-Chemical and other industries, vertical pressure vessels frequently have internal beds which are supported by the vessel walls. Hydrocracking and hydrotreating reactors, packed, tray and distillation columns and filters to name a few, are the common examples of such vessels. Each such bed is generally supported by a set of support beams, sectional bed supports (gratings) and a segmented circumferential ring; the ring supporting the peripheral edges of the gratings. The design details of these beds vary considerably. This paper covers a simple and user friendly procedure for the design of bed support beams, regardless of the complexities of the design details and can be applied in all the design situations. From practical stand point even number of beams are used for each bed which are symmetrically placed with respect to the vessel cross sectional centerline. It is also desirable that such beams be equally spaced to enable standard width grating (grid) sections. The spacing of beams, especially in complex hydrocracker reactor beds with high design pressures (3,000 psi) and design temperatures (900°F) is dictated by the size and weight of the largest beams and bed (grid) sections, which are installed through the top reactor man way openings.