Plate Grid Distributor Skirt Design for Thermal Expansion

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Solution Overview

Problem

Large plate grid distributors and plenums in chemical processing systems face mechanical support challenges due to thermal expansion and contraction in hot environments, leading to difficulties in maintaining stable distribution of fluids.

Innovation Solution

The implementation of plate grid distributors and plenums with a skirt design featuring multiple portions, where the first portion is in direct contact with the plate and has a lower allowable stress, and the second portion, positioned below, has a higher allowable stress, allowing for bending without failure during thermal expansion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the plate grid distributor is made larger to increase processing capacity, then productivity is improved, but mechanical support becomes more challenging due to thermal expansion and contraction

Engineering Contradiction:

Improveprocessing capacityVSAvoidmechanical support stability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The skirt is divided into multiple segments (first skirt segment, second skirt segment, third skirt segment) with different materials and properties. Each segment handles specific mechanical and thermal loads, allowing the large plate grid distributor to maintain structural integrity while accommodating thermal expansion and contraction during operation

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The skirt employs composite construction with different material layers: an inner corrosion-resistant alloy layer (e.g., Inconel 625) for chemical resistance, a middle structural steel layer for mechanical strength, and an outer insulation layer for thermal management. This composite structure enables the large distributor to withstand thermal stresses while maintaining mechanical support stability

Inventive Principle:

Principle #40Composite materials

2Productivity

If the plate grid distributor operates in hot environments to enable chemical reactions, then productivity is improved, but thermal expansion causes the plate to expand outward towards outer walls

Engineering Contradiction:

Improvechemical reaction efficiencyVSAvoidplate dimensional stability

Core Design Contradiction:

ProductivityVSShape

Solution Approach 1:

The design explicitly accounts for thermal expansion by providing clearance space between the plate outer periphery and the reactor outer walls. The skirt structure is configured to accommodate the outward expansion of the plate when exposed to high temperatures during chemical reactions, preventing mechanical interference while maintaining operational productivity

Inventive Principle:

Principle #37Thermal expansion

Solution Approach 2:

The skirt is designed with flexible connections and expansion joints that allow dynamic adjustment as the plate expands and contracts with temperature changes. This dynamic capability enables the plate grid distributor to maintain both high-temperature operational efficiency and dimensional stability throughout the reaction cycle

Inventive Principle:

Principle #15Dynamics

3Strength

If the skirt material has high allowable stress to withstand mechanical stresses, then strength is improved, but material costs increase

Engineering Contradiction:

Improveskirt allowable stressVSAvoidmaterial cost

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

Different portions of the skirt are constructed with different materials matched to their specific functional requirements: the inner surface near the plate uses high-strength corrosion-resistant alloy for areas experiencing both mechanical and chemical stress, while outer portions use lower-cost structural steel with insulation. This localized material selection achieves necessary strength while controlling overall material costs

Inventive Principle:

Principle #3Local quality

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This design provides adequate mechanical support to the plate grid distributors and plenums, ensuring continued functionality during thermal expansion and contraction, even in large reactors or vessels.

Implementation Method 1

As temperatures of the plate grid distributors may elevate, the plate may thermally expand outwards towards outer walls of the reactors or other vessels. This is particularly problematic in some fluidized bed vessels, where the hot environment may cause the plate of the plate grid distributor to thermally expand and contract.

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS20250128222A1Plate grid distributors and methods of using the same

Publication Date: 2025.04.24 DOW GLOBAL TECHNOLOGIES LLC

AI summary

According to one or more embodiments, a plate grid distributor for distributing a fluid in a vessel or a plenum for removing a fluid from a vessel may include a plate and a skirt. The skirt may be in direct contact with the plate and may include a first portion and a second portion. The first portion may be in direct contact with the plate and the second portion may be in direct contact with the first portion. The first portion may have a first allowable stress and the second portion may have a second allowable stress. According to one or more other embodiments, a method of distributing a fluid through a plate grid distributor in a vessel may include passing the fluid into the vessel and directing the fluid through the plate grid distributor.