Mechanical supports: lug support is primarily intended for which class of vessels in process equipment layout?

Introduction / Context:
Vessel supports must safely transfer loads to foundations while accommodating thermal expansion and maintenance. Common support types include skirts (for tall vertical vessels), saddles (for horizontal drums), and lugs (pads or brackets welded to the shell). Selecting the right support type is a standard mechanical design decision.

Given Data / Assumptions:

• Vessels operating at moderate pressure/temperature.
• Focus on generic, widely used support schemes.
• Objective: identify which class of vessels is typically supported by lugs.

Concept / Approach:
Lug supports are welded brackets attached to the vessel shell, typically used to suspend or anchor small vessels (often small vertical drums or columns) to structural steel. For larger or heavier vessels, local shell stresses at lugs become excessive; therefore, skirts (vertical) or saddles (horizontal) are preferred to distribute loads and reduce stress concentrations.

Step-by-Step Solution:

Verification / Alternative check:
Vendor catalogs and design manuals show lug-supported filters, small receivers, and small reactors mounted to frames, while large towers use skirts and horizontal drums use saddles.

Why Other Options Are Wrong:

• Large horizontal cylindrical: typically require saddle supports to spread loads.
• Tall or thick-walled tall vessels: normally use skirts to manage overturning and thermal expansion.

Common Pitfalls:
Overusing lugs on heavier vessels causing local overstress; neglecting proper pad reinforcement; not allowing for thermal expansion at the steelwork interface.

Final Answer:
Small