Selective Oxy-Fuel Burner for Rotary Furnace

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Solution Overview

Problem

Conventional rotary furnaces face inefficiencies in heat transfer and energy distribution due to incomplete flame development and obstruction by large chunks of scrap, leading to non-uniform heating and increased melt losses.

Innovation Solution

A rotary furnace with a selective oxy-fuel burner system featuring multiple burner elements that can be actively or passively modulated to create longer, penetrating flames, directing heat flux uniformly across the furnace through strategic positioning and real-time feedback from sensors, ensuring even heating and minimizing oxidative melt losses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a conventional nozzle-mixed burner is used in a double-pass rotary furnace, then the flame can extend to the rear end of the furnace providing significant heat transfer time, but large chunks of scrap block the flame development causing incomplete combustion and non-uniform heating

Engineering Contradiction:
Improvetemperature distribution uniformityVSAvoidmelting efficiency
Core Design Contradiction:
TemperatureVSProductivity

Solution Approach 1:

The burner is divided into multiple independently controllable burner elements (e.g., 3-5 elements) arranged across the burner face. Each element can be individually modulated between active and passive states, allowing the flame pattern to be segmented and redirected around obstructions rather than blocked by a single continuous flame

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The burner system dynamically adjusts the state of individual burner elements based on real-time feedback from sensors detecting charge position, flame characteristics, and temperature distribution. This dynamic modulation allows the flame pattern to adapt continuously to changing furnace conditions and obstruction locations

Inventive Principle:
Principle #15Dynamics

2Power

If the firing rate of the burner is increased to reach the back of the furnace, then more heat is available, but this exacerbates overheating of the front portion and non-uniform heating

Engineering Contradiction:
Improveheat inputVSAvoidfront portion overheating
Core Design Contradiction:
PowerVSTemperature

Solution Approach 1:

Different burner elements are selectively activated or deactivated based on the specific heating needs of different furnace zones. When the front portion is adequately heated, the corresponding burner elements are modulated to passive state, redirecting heat input to the rear portion without increasing overall firing rate

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

Temperature sensors positioned at multiple locations (front, middle, and rear of the furnace) provide real-time feedback to the control system. This feedback enables automatic adjustment of individual burner element states to maintain uniform temperature distribution across the furnace

Inventive Principle:
Principle #23Feedback

3Adaptability or versatility

If large chunks of scrap are processed, then the furnace can handle varied charge sizes, but they block flame evolution causing incomplete mixing and elevated flue gas temperatures with energy loss

Engineering Contradiction:
Improvecharge handling capabilityVSAvoidflue gas energy loss
Core Design Contradiction:
Adaptability or versatilityVSLoss of energy

Solution Approach 1:

Instead of allowing the flame to extend forward and be blocked by obstructions, the burner elements are modulated to create flames that bypass obstructions and target the rear portion of the furnace directly. This inverts the conventional flame propagation direction, ensuring complete combustion occurs despite charge blockages

Inventive Principle:
Principle #13The other way round (Inversion)

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

The solution achieves uniform temperature distribution and rapid cycle times by directing heat flux optimally, reducing overheating and energy loss, and improving melting efficiency while maintaining even heating across the furnace.

Implementation Method 1

a selective oxy-fuel burner system featuring multiple burner elements that can be actively or passively modulated to create longer, penetrating flames

Methodology Applied
Scientific EffectCombustion: Combustion

Implementation Method 2

heat transferred to the refractory above the metal bath can be transferred to conduction and convention as the furnace rotates

Methodology Applied
Scientific EffectConduction (thermal): Conduction (thermal)

Implementation Method 3

heat transferred to the refractory above the metal bath can be transferred to conduction and convention as the furnace rotates

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 4

the melting performance of a conventional rotary furnace is usually more efficient than a stationary furnace as a result of interaction between refractory and the metal bath as the furnace rotates

Methodology Applied
Scientific EffectRotational motion:

Data Source

PatentEP3098512B1Rotary furnace and method of operating a rotary furnace
Publication Date: 2019.03.06 AIR PROD & CHEM INC
  • EP3098512B1 patent drawingFigure 1A
  • EP3098512B1 patent drawingFigure 1B
  • EP3098512B1 patent drawingFigure 2A

AI summary

A selective oxy-fuel burner (10) for mounting in a charge door of a rotary furnace, including at least two burner elements (20) each oriented to fire into different portions of the furnace, each burner element including a selective distribution nozzle (22) configured to flow a first reactant; and a proportional distribution nozzle (24) configured to flow a second reactant; at least one sensor to detect one or more process parameters related to furnace operation; and a controller programmed to independently control the first reactant flow to each selective distribution nozzle (22) based on the detected process parameters such that at least one burner element is active and at least one burner element is passive; wherein the second reactant is substantially proportionally distributed to the proportional distribution nozzles (24); and wherein the first reactant is one of a fuel and an oxidant and wherein the second reactant is the other of a fuel and an oxidant.