Abnormal Event Detection in Delayed Coking Units

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Solution Overview

Problem

Delayed Coking Units (DCUs) face challenges in detecting abnormal operations due to the complexity and high-severity nature of the process, leading to premature coking, foam carryover, and reliability issues with the coker fractionator, which can result in significant economic losses, safety hazards, and equipment damage.

Innovation Solution

A method and system for abnormal event detection (AED) in DCUs that compares online measurements to models of normal operation, automatically detects deviations, and provides the operator with timely information to take corrective actions, using fuzzy logic and Principal Component Analysis (PCA) to aggregate evidence and indicate the probability of problems, thereby reducing the likelihood of missed events and enabling early intervention.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional alarm systems are used to detect abnormal operations in DCUs, then the system structure remains simple, but the detection precision is insufficient leading to late notification and missed events

Engineering Contradiction:
Improvedetection precisionVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The detection system is segmented into multiple specialized modules including PCA module for pattern recognition, fuzzy logic module for uncertainty handling, and multiple detection algorithms针对不同 types of abnormalities. Each module processes specific aspects of the complex DCU operation data, improving detection precision without overwhelming the overall system management.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system transitions from traditional single-dimensional threshold-based alarm detection to multi-dimensional analysis by incorporating PCA transformation that projects high-dimensional process data into principal component space. This dimensional transformation enables detection of subtle abnormal patterns that single-parameter monitoring cannot capture.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Loss of time

If traditional monitoring methods are used, then the device complexity is low, but the response time is delayed resulting in economic losses and safety hazards

Engineering Contradiction:
Improveresponse timeVSAvoidsystem complexity
Core Design Contradiction:
Loss of timeVSDevice complexity

Solution Approach 1:

The system performs preliminary detection and analysis continuously in the background using PCA and fuzzy logic algorithms, preparing abnormality assessments before actual alarm conditions occur. This preliminary action enables the system to notify operators of developing abnormalities before they escalate into critical failures, reducing response time and preventing economic losses.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements continuous feedback loops where detection results feed back into process control and operator notification systems. The fuzzy logic module continuously adjusts abnormality assessments based on incoming process data and historical patterns, providing real-time feedback that enables timely corrective actions before abnormalities worsen.

Inventive Principle:
Principle #23Feedback

Data Source

PatentUS7720641B2Application of abnormal event detection technology to delayed coking unit
Publication Date: 2010.05.18 EXXONMOBIL TECHNOLOGY & ENGINEERING CO
  • US7720641B2 patent drawing
  • US7720641B2 patent drawing
  • US7720641B2 patent drawing

AI summary

The present invention is a method for detecting an abnormal event for process units of a Delayed Coking Unit. The method compares the operation of the process units to statistical and engineering models. The statistical models are developed by principal components analysis of the normal operation for these units. The engineering models are based statistical and correlation analysis between variables. If the difference between the operation of a process unit and the normal model result indicates an abnormal condition, then the cause of the abnormal condition is determined and corrected.