Parallel-Type Lance Design for Blast Furnace Cooling and Combustion
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Solution Overview
Problem
Conventional blast furnace operation methods face challenges in enhancing cooling ability and combustibility while reducing specific consumption of reducing materials, often resulting in increased lance diameter, clogging risks, and higher process costs due to complex multiple-tube structures.
Innovation Solution
A blast furnace operation method utilizing a parallel-type lance with three independent blowing tubes bundled and housed in an outer tube, where the solid reducing material and gaseous reducing material blowing tubes are positioned above the combustible gas tube, maintaining a specific angle and diameter range to optimize airflow and reduce material consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a multiple-tube type lace is used to blow solid reducing material and gaseous reducing material simultaneously, then cooling ability is improved, but the gap between tubes becomes extremely narrow which restricts gas flow and reduces combustibility improvement
Solution Approach 1:
The lance is divided into multiple independent blowing tubes (solid reducing material tube, gaseous reducing material tube, combustible gas tube, and cooling water tubes) that operate independently. This segmentation allows each tube to have optimized dimensions for its specific function, avoiding the narrow gap problem of multiple-tube designs while maintaining effective cooling through separate cooling water circulation paths.
2Quantity of substance
If the diameter of the lace is increased to ensure gas flow rate, then combustibility is improved, but the blast volume in the blowpipe decreases and the risk of breaking surrounding refractories increases
Solution Approach 1:
The design transitions from a single large-diameter lance to a multi-tube configuration where multiple smaller tubes are arranged in specific spatial dimensions. This allows the total gas flow capacity to be maintained or improved while the outer diameter remains constrained, preserving blast volume and reducing mechanical stress on surrounding refractories.
3Quantity of substance
If multiple small-size tubes are arranged around the main tube in parallel, then gas flow is improved, but the risk of clogging increases and process cost increases
Solution Approach 1:
Different tube sections have different diameters optimized for their specific functions: the solid reducing material tube has sufficient diameter to prevent clogging, while other tubes are sized appropriately for their gas flow requirements. The cooling water tubes are positioned to provide localized cooling at critical heat zones, improving reliability without requiring uniform small-diameter tubes throughout.
4Quantity of substance
If a multiple-tube structure is changed into a parallel-tube structure, then gas flow is improved, but the pressure loss increases and the diameter becomes large
Solution Approach 1:
Multiple blowing tubes are nested concentrically within the lance structure, with each tube positioned in a specific radial and axial location. This nested arrangement allows efficient gas flow paths with minimal pressure loss, as each gas stream has its own dedicated pathway to the tuyere tip, while the overall lance diameter remains compact.
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 increases cooling ability and combustibility, decreases specific consumption of reducing materials, and maintains a smaller lance diameter, thereby reducing the risk of clogging and process costs, while improving combustion efficiency.
Implementation Method 1
blowing a flammable gaseous reducing material such as LNG (liquefied natural gas) or a combustible gas together with a solid reducing material such as pulverized coal or the like into the furnace through tuyeres to raise combustion temperature at tips of the tuyeres
Data Source
AI summary
A method is provided for operating a blast furnace by blowing a solid reducing material, a flammable gaseous reducing material and a combustible gas into a blast furnace from tuyeres through a lance into a blast furnace, wherein a parallel type lance prepared by bundling three independent blowing tubes in parallel and integrally housing them into an outer tube is used, and either one or both of the gaseous reducing material and the combustible gas and the solid reducing material are simultaneously blown through the respective blowing tubes, while the blowing tube for the solid reducing material and the blowing tube for the gaseous reducing material are positioned above the blowing tube for the combustible gas in the blowing through the parallel type lance as well as a lance structure thereof.