Reduced Puffing Needle Coke via Nitrogen Removal
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Solution Overview
Problem
Existing methods for producing needle coke for graphite electrodes fail to effectively reduce puffing caused by nitrogen, leading to inferior electrode quality with lower density and strength, often requiring energy-intensive hydrogenation processes and additive use.
Innovation Solution
A nitrogen removal system using adsorbents like activated carbon, alumina, or silica-based materials to physically remove nitrogen from coal tar distillate feedstocks without additives or high-temperature hydrogenation, reducing nitrogen content from 0.4% to 0.03% by weight, thereby minimizing puffing during graphitization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional coking processes are used to produce needle coke from coal tar distillate, then needle coke is produced, but nitrogen content remains high causing puffing during graphitization
Solution Approach 1:
The invention applies preliminary action by removing nitrogen from the coal tar distillate feedstock before the coking process. This is achieved through hydrotreating the feedstock to reduce nitrogen content to below 0.1 wt%, preventing nitrogen-induced puffing during subsequent graphitization and maintaining electrode integrity throughout the manufacturing process
Solution Approach 2:
The invention changes the chemical composition parameters of the feedstock by controlling nitrogen content through hydrotreating. By adjusting the nitrogen concentration to below 0.1 wt% before coking, the process transforms the feedstock properties to prevent harmful puffing effects during graphitization while maintaining productive carbon yield
2Device complexity
If nitrogen is not removed from feedstock, then coking process is simpler, but puffing occurs during graphitization causing cracks and voids
Solution Approach 1:
The invention performs preliminary nitrogen removal through hydrotreating the coal tar distillate before coking. This advance treatment prevents nitrogen-induced puffing during graphitization, ensuring high electrode density and structural integrity without requiring complex post-processing or additive systems
Solution Approach 2:
The invention extracts nitrogen from the coal tar distillate feedstock through hydrotreating before coking. By removing the harmful nitrogen component in advance, the process prevents puffing-related defects such as cracks and voids, achieving high manufacturing precision in electrode density and strength
3Reliability
If hydrogenation processes are used to remove nitrogen, then puffing is reduced, but energy consumption increases significantly
Solution Approach 1:
The invention changes the feedstock composition parameters by reducing nitrogen content through hydrotreating before coking. This parameter change achieves puffing resistance during graphitization while avoiding the need for energy-intensive hydrogenation processes during electrode manufacturing
Solution Approach 2:
The invention applies preliminary hydrotreating to remove nitrogen from feedstock before coking, establishing puffing resistance in advance. This approach eliminates the need for subsequent high-energy hydrogenation processes, significantly reducing hydrogen energy consumption while maintaining reliable puffing resistance
4Strength
If additives are used to inhibit puffing, then electrode strength is maintained, but manufacturing cost and process complexity increase
Solution Approach 1:
The invention extracts nitrogen from the feedstock through hydrotreating before coking, eliminating the root cause of puffing. This approach maintains electrode strength by preventing puffing-related defects without requiring additional puffing inhibitor additives, simplifying the manufacturing process
Solution Approach 2:
The invention performs preliminary nitrogen removal through hydrotreating, preventing puffing before it occurs. This advance action maintains electrode strength by avoiding puffing-induced cracks and voids, eliminating the need for complex additive systems and maintaining manufacturing simplicity
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 process produces reduced-puffing needle coke with improved density and strength characteristics, reducing thermal and hydrogen energy consumption, and maintaining electrode integrity by minimizing nitrogen-induced expansion during graphitization.
Implementation Method 1
A nitrogen removal system using adsorbents like activated carbon, alumina, or silica-based materials to physically remove nitrogen from coal tar distillate feedstocks
Data Source
AI summary
A reduced puffing needle coke is formed, which includes a reduced nitrogen content within the coke so that the coke particles do not experience as much puffing during the formation of graphitized carbon articles produced from such coke upon heating to graphitization temperatures.