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Scallops

Apollo screens > Products > Hydrocarbon Processing > Scallops
PRODUCT OVERVIEW
Apollo Screens’ Scallop-Type Wedge Wire Scale Traps are modular reactor internals engineered for hydrotreating and hydrocracking units to effectively capture metallic scale, rust, coke fines, and other solid contaminants before they reach the catalyst bed.

Designed as curved (scallop-shaped) wedge wire segments, these traps are assembled circumferentially inside the reactor, providing high mechanical strength, large trapping surface area, and excellent fouling resistance.

Why Scallop Design?

Scallop-type scale traps are globally adopted in hydroprocessing reactors due to their modularity, strength, and ease of installation.
Key advantages include:
• Modular construction allows easy installation and replacement
• Curved geometry fits precisely inside reactor shells
• Uniform circumferential coverage minimizes localized fouling
• Superior load-bearing capability during catalyst dumping
• Reduced risk of distortion compared to large monolithic baskets

How Scallop Scale Traps Work

  1. Feed enters the reactor and passes through the distributor tray.
  2. Solid contaminants are intercepted by the Apollo scallop wedge wire scale traps installed above the catalyst bed.
  3. Contaminants are spread across multiple scallop segments, preventing concentrated crust formation.
  4. Clean, evenly distributed flow reaches the catalyst bed, maintaining activity and pressure drop stability.
  5. Trapped debris is removed during scheduled turnarounds or remains structurally stable during catalyst unloading.

Applications

• Naphtha & Diesel Hydrotreaters
• Residue Hydrotreaters (RHT)
• Hydrocrackers (HCU)
• Units processing FCC or coker-derived feeds
• Fouling-prone reactors handling opportunity crudes

Performance Benefits

• Slows pressure-drop rise across catalyst beds
• Protects high-value catalyst from hard contaminants
• Improves flow distribution at the top of the bed
• Extends catalyst cycle length
• Reduces unplanned shutdowns and maintenance costs

Why Apollo Screens

• Proven wedge wire manufacturing expertise
• Precision slot accuracy and repeatability
• Custom-engineered reactor internals
• Trusted by OEMs, EPCs, and refiners worldwide
• Reliable performance in severe hydroprocessing environments

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Apollo Wedge Wire Advantage

Apollo scallops are manufactured using precision V-profile (wedge) wire technology, offering:
• Self-cleaning slot geometry that resists blinding
• High open area for minimal pressure drop
• Accurate slot control for reliable scale interception
• Heavy-duty support rods welded for high mechanical integrity
This ensures consistent performance under high temperature, high pressure, and abrasive feed conditions.

Design & Construction Options

Apollo Screens custom-engineers scallop scale traps based on reactor dimensions and operating conditions.
Typical specifications:
• Slot openings: 0.05 mm to 3.0 mm (customized)
• Materials:
o SS304 / SS316 / SS316L
o Duplex & Super Duplex stainless steels
o Special alloys for high-TAN or corrosive feeds
• Configuration:
o Individual curved scallop segments
o Bolted or seated on support rings
o Compatible with tray-integrated or stand-alone installations

Inspection & Maintenance

• Designed for visual inspection during turnarounds
• Mechanically robust to withstand catalyst dumping
• Easy cleaning by wire brushing or washing
• Individual scallops can be replaced without removing the full assembly

Sustainable Solutions for Industry

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Power & Energy

Comprehensive internal components optimized for maximum separation efficiency, operational safety, and reduced maintenance cycles.
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