Injection Lance Design for Molten Iron Gasifier
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Solution Overview
Problem
The service life of injection lances in molten iron and slag baths is short due to high heat and scouring forces, leading to frequent replacements and safety risks, and there are challenges with heat recovery and continuous operation in existing gasification processes.
Innovation Solution
A gasifier system that includes a liquid level adjusting mechanism to facilitate easy maintenance and replacement of injection lances, uses non-water-cooled lances with wear-resistant materials, and employs continuous slag discharge and heat recovery to extend lance life and improve operational efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If injection lances are used in molten iron and slag baths for gasification, then organic solid waste can be converted into syngas efficiently, but the service life of injection lances is short due to high heat and scouring forces
Solution Approach 1:
The injection lance is divided into multiple sections with different material properties. The lower section exposed to molten iron uses wear-resistant materials, while the upper section uses heat-resistant materials, allowing each section to withstand specific environmental stresses and extend overall lance life
Solution Approach 2:
The injection lance is constructed using composite materials that combine the advantages of different materials - high-temperature resistance, wear resistance, and thermal shock resistance - to withstand the harsh dual-molten-bath environment and extend service life while maintaining gasification efficiency
2Reliability
If injection lances are frequently replaced for maintenance, then operational safety can be maintained, but production continuity is disrupted and time is lost
Solution Approach 1:
The injection lance is designed with a replaceable lower section that can be pre-manufactured and stored. When wear occurs, this pre-prepared section can be quickly swapped without requiring complex on-site manufacturing or lengthy replacement procedures, minimizing production downtime while maintaining safety
Solution Approach 2:
The injection lance system incorporates quick-connect mechanisms and modular design that enable dynamic replacement of worn components during scheduled maintenance windows, allowing rapid reconfiguration and minimizing disruption to continuous gasification operations
3Duration of action of stationary object
If water-cooled injection lances are used to extend service life, then lance durability improves, but safety risks increase due to potential water leakage and thermal shock
Solution Approach 1:
The injection lance uses inexpensive, replaceable consumable sections made of wear-resistant materials that are designed to be replaced periodically rather than continuously cooled. This eliminates water cooling systems entirely, removing leakage risks while maintaining operational safety through scheduled replacement of worn components
4Loss of energy
If heat recovery systems are added to the gasifier, then energy efficiency improves, but device complexity increases
Solution Approach 1:
The heat recovery function is merged with the existing slag discharge system. The slag outlet serves dual purposes: discharging molten slag and acting as the heat exchange interface for recovering thermal energy from the slag to preheat incoming air or water, thereby reducing energy losses without adding separate complex heat recovery equipment
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 system significantly extends the service life of injection lances, enhances safety, and improves energy efficiency by enabling continuous operation and effective heat recovery, reducing the need for frequent replacements and minimizing safety hazards.
Implementation Method 1
the high-speed gas jet is blown into the molten metal or molten slag by an injection lance to form a fierce gas-liquid mixed flow, and bring about intense stirring of the molten bath
Implementation Method 2
form a fierce gas-liquid mixed flow, and bring about intense stirring of the molten bath
Implementation Method 3
The temperature of molten iron bath and molten slag bath is as high as 1400-1600° C., and organic molecules are rapidly pyrolyzed into a carbon product within tens of milliseconds after being contacted
Implementation Method 4
have good effect on momentum transfer, heat transfer and mass transfer of molten metal or molten slag bath
Implementation Method 5
have good effect on momentum transfer, heat transfer and mass transfer of molten metal or molten slag bath
Data Source
AI summary
A gasifier for organic solid waste by injection into molten iron and slag bath includes a gasification furnace, a liquid level adjusting furnace and a slag discharge and heat exchange shaft furnace. The liquid level adjusting furnace, in communication with the bottom of the gasification furnace, contains 1200-1700° C. molten iron-based alloy liquid, which is covered with molten liquid slag layer. When gas pressure above or liquid volume in the liquid level adjusting furnace increases, liquid level of the molten liquid in the gasification furnace rises simultaneously. A particle material injection lance is immersed, through which organic particles to be gasified are blown into molten bath, and oxygen gas or oxygen-enriched air as gasifying agent is blown into the melt at the same time. Organic substance is gasified into CO-rich and H2-rich syngas, and most of inorganic substance enters molten slag and is discharged termly.