Catalyst Regeneration Loop Decoking for Coke-Fouled Heat Exchangers

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Decoking operations for specialized heat exchangers like welded plate and large vertical heat exchangers are challenging due to the difficulty in efficiently removing deposited carbonaceous materials, which can cause corrosion, reduce heat transfer efficiency, and increase maintenance costs.

Innovation Solution

Repurpose the catalyst regeneration gas loop to perform decoking operations using nitrogen circulation, re-routing the flow to bypass burn and calcination zones and utilize existing equipment for decoking, allowing for controlled combustion of coke deposits using existing catalyst regeneration systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If steam is used for decoking operations, then coke deposits can be removed effectively, but corrosion and integrity risks increase

Engineering Contradiction:

Improvedecoking efficiencyVSAvoidcorrosion risk

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent applies inert atmosphere by using nitrogen gas instead of steam for decoking operations. Nitrogen is introduced into the heat exchanger to burn off coke deposits in an inert environment, eliminating the corrosion and integrity risks associated with steam while maintaining effective decoking capability.

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

2Adaptability or versatility

If new decoking equipment is installed, then decoking capability is improved, but capital expenditures increase

Engineering Contradiction:

Improvedecoking capabilityVSAvoidcapital expenditure

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent applies universality by enabling the existing catalyst regeneration gas loop to perform dual functions: catalyst regeneration and heat exchanger decoking. By configuring existing equipment to handle decoking operations, the system achieves multi-functionality without requiring new dedicated decoking equipment, thereby avoiding additional capital expenditures.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent applies self-service by having the existing catalyst regeneration system perform decoking operations on heat exchangers within the same process unit. The system serves itself by using its own infrastructure (gas loop, compressors, heaters) to accomplish decoking, eliminating the need for external or dedicated decoking equipment.

Inventive Principle:

Principle #25Self-service

3Productivity

If once-through nitrogen flow is used, then decoking can be performed, but nitrogen consumption increases

Engineering Contradiction:

Improvedecoking operationVSAvoidnitrogen consumption

Core Design Contradiction:

ProductivityVSLoss of substance

Solution Approach 1:

The patent applies continuity of useful action by implementing a recirculating nitrogen flow system. Nitrogen that exits the heat exchanger is not discarded but is recirculated back through the system after being reheated and repressurized. This continuous circulation allows the same nitrogen to perform multiple decoking cycles, significantly reducing overall nitrogen consumption compared to once-through flow.

Inventive Principle:

Principle #20Continuity of useful action

Solution Approach 2:

The patent applies discarding and recovering by capturing nitrogen that has passed through the heat exchanger and redirecting it back into the system. Instead of discarding the nitrogen after a single use, the system recovers it through the recirculation loop, where it is reheated and repressurized for continued use in decoking operations.

Inventive Principle:

Principle #34Discarding and recovering

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 approach reduces capital expenditures by utilizing existing equipment, minimizes corrosion risks, and enables efficient decoking of heat exchangers with lower nitrogen consumption, thereby lowering operational costs and maintaining system integrity.

Implementation Method 1

combusting, within the heat exchanger, the coke deposits with the oxygen of the regeneration gas, thereby removing the coke deposits from the surface of the heat exchanger

Methodology Applied

Scientific EffectCombustion: Combustion

Implementation Method 2

combusting, within the heat exchanger, the coke deposits with the oxygen of the regeneration gas

Methodology Applied

Scientific EffectOxidation: Oxidation

Implementation Method 3

Heat exchanger decoking

Methodology Applied

Scientific EffectHeat transfer: Conduction (thermal)

Data Source

PatentUS12564831B2Catalyst regeneration system utilization for heat exchanger decoking

Publication Date: 2026.03.03 SAUDI ARABIAN OIL CO

AI summary

A catalyst regeneration gas loop is operated in a heat exchanger decoking mode. A regeneration gas is diverted away from a burn zone of the catalyst regeneration gas loop and to a heat exchanger, where coke deposits are disposed on a surface of the heat exchanger. The regeneration gas is prevented from flowing to an oxychlorination/calcination zone of the catalyst regeneration gas loop. Within the heat exchanger, the coke deposits are combusted with oxygen of the regeneration gas, thereby removing the coke deposits from the surface of the heat exchanger and producing carbon dioxide. Oxygen is replenished to the regeneration gas. The regeneration gas is recycled to the heat exchanger.