Metallurgical Melt CO Flow Control via Feedback

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Solution Overview

Problem

In metallurgical smelting processes, the carbon monoxide discharge is not always proportional to the oxygen supply, leading to unpredictable gas bubble formation and potential boiling hazards, which can cause safety and material damage.

Innovation Solution

A method to control carbon monoxide discharge by determining the actual and target carbon flow values, comparing them to prevent sudden gas bubble formation, and adjusting oxygen supply or adding carbon to maintain a stable carbon flow, thereby preventing boiling effects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If oxygen is blown into the melt to oxidize carbon, then decarburization is achieved and high-quality steel is produced, but carbon monoxide accumulates in the melt and causes sudden gas bubble escape and boiling

Engineering Contradiction:
Improvecarbon content controlVSAvoidprocess stability
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent implements a feedback control system that continuously monitors the actual carbon flow from the melt and compares it with the target carbon flow calculated from oxygen supply rate and melt composition. When deviation is detected (indicating CO accumulation), the system automatically adjusts oxygen supply or adds carbon to prevent boiling, thereby resolving the contradiction between achieving decarburization and maintaining process stability

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent calculates the target carbon flow in advance based on the oxygen supply rate and current melt composition before CO accumulation occurs. This preliminary calculation allows the control system to anticipate and prevent CO buildup by adjusting process parameters proactively, rather than reactively responding after boiling has started

Inventive Principle:
Principle #10Preliminary action

2Duration of action of stationary object

If the liquid melt retains carbon monoxide metastably, then gas bubble formation is delayed, but sudden gas escape occurs when the critical point is reached causing boiling and safety hazards

Engineering Contradiction:
Improvegas retention timeVSAvoidboiling hazard
Core Design Contradiction:
Duration of action of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The monitoring and feedback control system detects early signs of CO accumulation through actual carbon flow measurements. By comparing actual versus target carbon flow, the system identifies when the melt is approaching its CO retention capacity and takes corrective action before the critical point is reached, thus extending safe gas retention time while preventing sudden boiling

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The control system prepares countermeasures in advance by maintaining a model of the melt's CO capacity. When CO accumulation approaches dangerous levels, the system pre-adjusts oxygen supply or introduces carbon to create a buffer, preventing the sudden release of accumulated gas and cushioning against the boiling hazard before it occurs

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Object-generated harmful factors

If carbon monoxide is oxidized in the gas space or by afterburners, then CO is converted to CO2, but the process complexity and energy consumption increase

Engineering Contradiction:
Improvecarbon monoxide emissionVSAvoidgas treatment system
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

Instead of treating CO as a harmful byproduct requiring complex treatment systems, the patent converts it into a useful process parameter. By measuring actual carbon flow and using it for feedback control, the previously harmful CO accumulation becomes a source of process optimization information, enabling precise control of decarburization while minimizing the need for additional gas treatment equipment

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent enables the smelting process itself to manage CO production through self-regulation. By using actual carbon flow measurements from the exhaust gas to control oxygen supply and carbon addition, the system makes the process self-correcting, eliminating CO accumulation at its source rather than requiring external treatment systems to handle the harmful emissions

Inventive Principle:
Principle #25Self-service

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 method ensures a constant and stable carbon flow, reducing the risk of boiling and enhancing operational reliability by allowing timely intervention to manage carbon monoxide accumulation and formation.

Implementation Method 1

For decarburization, oxygen (O 2 ) is blown into the melt, which oxidizes the carbon contained in the melt. The carbon monoxide (CO) produced in this way forms gas bubbles in the melt

Methodology Applied
Scientific EffectOxidation: Oxidation

Implementation Method 2

In a gas space above the melt, carbon monoxide can be partially oxidized to carbon dioxide or completely oxidized by afterburners

Methodology Applied
Scientific EffectOxidation: Oxidation

Implementation Method 3

The carbon monoxide (CO) produced in this way forms gas bubbles in the melt, which rise to the surface and penetrate the slag on the melt surface

Methodology Applied
Scientific EffectBuoyancy: Archimedes' Principle (Buoyancy)

Data Source

PatentEP2099940B1Method of regulating the output of carbon monoxide in a metallurgical melting process
Publication Date: 2012.03.14 SIEMENS AG
  • EP2099940B1 patent drawingFigure 1
  • EP2099940B1 patent drawingFigure 2
  • EP2099940B1 patent drawingFigure 3

AI summary

A description is given of a method of regulating the output of CO in steel production, in which oxygen is introduced into a melt to remove carbon present, the actual value of the carbon stream evolved from the melt is determined, the intended value of the evolved carbon stream derived from the amount of oxygen introduced and the carbon content of the melt is calculated, intended and actual values are compared with one another and if the actual value is below the intended value, measures for preventing boiling are undertaken.