Horizontal Preheating Duct Segmentation for Steel Scrap
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Solution Overview
Problem
The traditional CONSTEEL steel scrap preheating method in electric arc furnaces has low thermal efficiency due to insufficient heat exchange between flue gas and steel scrap, primarily because of a large flue gas passage and insufficient mixing of flue gas flow rates, leading to reduced power-saving effects compared to shaft furnaces.
Innovation Solution
A horizontal continuous feeding preheating device with a divided flue gas flow, utilizing two dust removal ports to optimize flue gas flow direction and height, and obliquely arranged burners to enhance heat exchange, reducing cold air entry and increasing the thermal efficiency of chemical energy usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a large area and large height flue gas passage is used in traditional CONSTEEL, then the flue gas flow rate is sufficient, but the heat exchange between burner gas and steel scrap is insufficient and thermal efficiency is low
Solution Approach 1:
The preheating duct is divided into multiple sections with different duct heights. The first preheating area has a smaller duct height while the second preheating area has a larger duct height. This segmentation allows sufficient flue gas flow rate in the second area while improving heat exchange efficiency in the first area where the steel scrap layer is directly impacted by flame efflux.
Solution Approach 2:
Different sections of the preheating duct are given different local characteristics. The first preheating area has reduced duct height to concentrate heat exchange, while the second preheating area maintains larger dimensions for sufficient flue gas flow. This local quality differentiation resolves the contradiction between overall gas flow and local heat exchange efficiency.
2Productivity
If chemical energy is added to a conveyor belt in traditional CONSTEEL, then steel scrap preheating efficiency is increased, but cold air mixing reduces the thermal efficiency of chemical energy
Solution Approach 1:
The preheating process is segmented into two areas with different functional characteristics. The first preheating area focuses on chemical energy utilization with reduced duct height to minimize cold air mixing, while the second area handles flue gas flow. This segmentation protects the thermal efficiency of added chemical energy while maintaining preheating efficiency.
Solution Approach 2:
The duct design preliminarily prevents cold air from mixing with the chemical energy combustion zone by reducing the duct height in the first preheating area. This preliminary anti-action protects the thermal efficiency of the added chemical energy before the preheating process begins.
Data Source
AI summary
The present invention belongs to the technical field of metallurgy, and discloses a horizontal continuous feeding preheating device and an enhanced preheating method therefor. The scheme comprises that two dust removal ports are arranged at the front and rear parts of a horizontal continuous feeding preheating duct, and the horizontal continuous feeding preheating duct is divided into an enhanced preheating area and a flue gas preheating area by the two dust removal ports arranged at the front and rear parts of the horizontal continuous feeding preheating duct; burners are installed in the enhanced preheating area, and the two dust removal ports are connected with a flue gas adjusting distributor respectively by a flue gas pipeline the steel scrap preheating efficiency of the burners and electric arc furnace flue gas is increased by controlling the flow rate and temperature of mixed flue gas.