Furnace Flame Modulation for Steel Temperature Profiles
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Solution Overview
Problem
Current furnaces for reheating iron and steel products are unable to achieve temperature differences greater than 50°C between the head and tail of the product, which is insufficient for new steel grades and very long products requiring steeper longitudinal temperature profiles.
Innovation Solution
The furnace is equipped with flame modulation burners in the preheating zone that can produce short or long flames, allowing for specific ignition modes to initiate desired temperature profiles by controlling the flame length and ignition time of burners, making the recovery zone active for temperature control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional burners with on/off mode control are used, then the furnace structure remains simple, but the temperature difference between head and tail of the product is limited to less than 50°C
Solution Approach 1:
The patent applies dynamics by making the flame length adjustable rather than fixed. The burners can dynamically change their flame length (short or long) to actively control the temperature profile in the recovery zone, enabling temperature differences of 60°C to 120°C between product ends while maintaining a relatively simple burner structure without complex additional components.
2Adaptability or versatility
If the recovery zone is used passively for heat recovery only, then the furnace operation is simple, but the temperature profile control capability is insufficient for new steel grades
Solution Approach 1:
The patent applies multi-functionality by making the recovery zone active rather than passive. The recovery zone serves dual purposes: it recovers heat from flue gases and simultaneously acts as a temperature control zone where flame-modulating burners create preferential flow patterns to establish desired temperature profiles. This enables the furnace to handle new steel grades requiring steep temperature gradients while maintaining straightforward operation through integrated control.
3Manufacturing precision
If flame-modulating burners are concentrated in heating zones only, then the burner configuration remains simple, but the temperature profile control is limited before product unloading
Solution Approach 1:
The patent applies preliminary action by placing flame-modulating burners in the preheating zone (first heating zone) rather than only in later heating zones. This allows the desired temperature profile to be initiated early in the heating process while the product is still in the recovery zone, providing precise temperature control before unloading without requiring complex burner distributions throughout the entire furnace.
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 enables temperature differences of up to 60°C to 120°C between the ends of the product, effectively addressing the limitations of existing furnaces by actively controlling the recovery zone to produce steep longitudinal temperature profiles.
Implementation Method 1
generate a preferential flow of fumes in the recovery zone by controlling the flame length of burners
Implementation Method 2
burners suitable for being controlled to produce a short flame or a long flame
Implementation Method 3
the product being reheated by the passage of the flue gases from all the burners
Data Source
Figure 1~2
Figure 3
AI summary
A furnace for reheating metallurgical products comprising longitudinal walls provided with lateral burners (A1, B1,... N1; A2, B2,... N2), the burners being arranged in successive rows, and transverse end walls, and provided with an inlet and an outlet for the products, the furnace comprising, at the inlet, a recovery area (R) followed immediately, in the direction of travel of the products, by a preheating area, then successive heating areas, a smoke discharge channel (5) being provided immediately upstream from the furnace inlet and the recovery area being traversed by the smoke discharged in this way, flowing in the opposite direction to the movement of the products, each product being disposed in such a way as to extend in a direction transverse to the direction of travel; the furnace is provided, in the preheating area, on each longitudinal wall, with lateral burners (A1, B1, A2, B2) with flame modulation, capable of being controlled to produce a short flame or a long flame, in such a way as to generate a preferential flow (4) of the smoke in the recovery area in order to establish, from the recovery step, any desired temperature profile for the product, in particular a sloping profile, for which the temperature difference is maintained or increased in order to obtain the desired profile by combining modulation of the flame length and modulation of the ignition time of the burners in the heating areas.