Scallop

Scallops form an outer slit screen in radial flow reactors. These devices are located along the inner vessel surface. 

Scallops are installed inside vertical reactors and distribute or collect the flow. 

Scallops hold the packing, collect and direct the flow. 

The center pipes, which collect the gas after the reaction.

The outer surface of the scallop contacts the catalyst. Depending on the project's requirements, it can be made of triangular wire or of perforated metal. 

The profile wire screen is best suited for segregating catalysts from feed and product streams in heterogeneous catalytic reactions, adsorption, or treatment operations. Effective separation of the catalyst occurs when the perforation size, or distance separating adjacent profile wires, is kept small enough to prevent migration of the particles into the interior of the conduits. The profile wire screen is furthermore designed to be resistant to catalyst particle plugging.

A reforming reaction section often employs scallops for gas distribution. Many reforming sections operate with the continuous addition and withdrawal of catalyst particles through a series of radial flow reactors.

Design features

• Large screen area, minimal hydraulic resistance

• Gaps between scallops to compensate the thermal expansion

• The usage of a slit screen stops catalyst leakage and excludes clogging of slots due to the usage of triangular wire

• Strict control of verticality, straightness and torsion tolerances