Blended Pitch Binder Composition for Graphite Electrode Quality
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Solution Overview
Problem
Current petroleum-derived pitches fail to meet the quality and safety requirements for use as hydrocarbon pitch binder materials in the manufacturing of graphite electrodes and carbon anodes due to low coke yield, softening points, and high benzo(a)pyrene content, while coal tar pitch is scarce and hazardous.
Innovation Solution
A pitch product is developed by blending petroleum-derived distillation residue and coal tar-derived distillation residue in specific ratios, achieving high asphaltenes concentration and thixotropic behavior, which enhances mechanical strength, electrical conductivity, and environmental friendliness, with a coke yield and softening point suitable for industrial applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If petroleum-derived pitch is used as a pure binder material, then availability and environmental friendliness improve, but coke yield decreases and quality parameters deteriorate
Solution Approach 1:
The patent combines petroleum-derived pitch and coal tar pitch in specific proportions (petroleum pitch: 10-70 wt%, coal tar pitch: 30-90 wt%) to create a blended binder that leverages the availability and environmental benefits of petroleum pitch while maintaining the high coke yield and quality parameters of coal tar pitch
Solution Approach 2:
The invention creates a composite pitch binder system by blending two different pitch types with distinct properties, where petroleum pitch provides availability and lower B(a)P content, while coal tar pitch ensures high coke yield and appropriate softening point, achieving a material that satisfies multiple conflicting requirements simultaneously
2Strength
If coal tar pitch is used as binder material, then mechanical strength and coke yield improve, but availability decreases and hazardous substance content increases
Solution Approach 1:
The patent applies local quality by using petroleum pitch (with lower B(a)P content) as the primary binder component while supplementing with coal tar pitch only to the extent necessary to achieve required mechanical strength and coke yield, thereby locally optimizing the hazardous substance content while maintaining performance
Solution Approach 2:
The invention changes the compositional parameters of the pitch binder by blending petroleum pitch (10-70 wt%) with coal tar pitch (30-90 wt%), adjusting the ratio to achieve the desired balance between mechanical strength, coke yield, and B(a)P content, with the blended product showing reduced hazardous substance content compared to pure coal tar pitch
3Quantity of substance
If petroleum-derived pitch with softening point below 100°C is used, then availability improves, but suitability for electrode manufacturing decreases
Solution Approach 1:
The patent changes the softening point parameter of the binder material by blending petroleum pitch (softening point <100°C) with coal tar pitch (softening point 110-130°C), achieving a blended product with intermediate softening point that falls within the required range for electrode manufacturing (100-130°C), thereby making petroleum pitch suitable for this application
4Quantity of substance
If petroleum-derived pitch with flash point below 200°C is used, then availability improves, but safety in hot mixing process decreases
Solution Approach 1:
The patent changes the flash point parameter of the binder material by blending petroleum pitch (flash point <200°C) with coal tar pitch (flash point >200°C), achieving a blended product with elevated flash point that exceeds 200°C, thereby eliminating safety concerns during hot mixing processes while retaining the benefits of petroleum pitch availability
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 blended pitch product provides a reliable, environmentally friendly alternative with improved mechanical strength, low porosity, and safety, meeting the requirements for graphite electrodes and carbon anodes, while ensuring ample availability and reduced hazardous substance content.
Implementation Method 1
A pitch product is developed by blending petroleum-derived distillation residue and coal tar-derived distillation residue in specific ratios, achieving high asphaltenes concentration and thixotropic behavior, which enhances mechanical strength, electrical conductivity
Data Source
AI summary
A pitch product having a petroleum-derived distillation residue and a coal tar-derived distillation residue, said pitch product characterized by a concentration of at least 84% asphaltenes (SARA). Further, the present invention is directed to a pitch binder including said pitch product useable in manufacturing of graphite electrodes for electric arc furnaces, and carbon anodes and Soederberg paste for aluminum production. The present invention is further directed also to a graphite electrode having said pitch binder, as well as to a carbon anode comprising said pitch binder. The present invention also provides a process for producing a pitch product including a petroleum-derived distillation residue and a coal tar-derived distillation residue, said process including a petroleum vacuum distillation process step for obtaining said petroleum-derived distillation residue, and a process for manufacturing a graphite electrode or a carbon anode including said process for producing a pitch product.