Pitch Particle Recycling Through Melt Reprocessing of Fines

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Solution Overview

Problem

The production of pitch particles from petroleum pitch is hindered by significant material loss in the form of fines during pulverization and deformation due to thermoplastic nature at softening temperatures, leading to waste and unsuitable shape retention during carbonization or graphitization.

Innovation Solution

A recycling loop is employed to convert pitch fines back into particles by melting and re-solidifying them in a grinding apparatus, followed by stabilization at elevated temperatures with controlled oxygen levels to increase the softening temperature and maintain shape integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If petroleum pitch is ground below softening temperature to produce pitch particles, then pitch particles can be produced, but significant material loss occurs in the form of pitch fines

Engineering Contradiction:

Improvepitch particle productionVSAvoidpitch fines

Core Design Contradiction:

Manufacturing precisionVSLoss of substance

Solution Approach 1:

The patent recovers pitch fines that would otherwise be discarded by melting them above softening temperature and re-solidifying them into usable pitch particles, thereby converting waste material back into valuable product and reducing overall material loss

Inventive Principle:

Principle #34Discarding and recovering

Solution Approach 2:

The patent changes the temperature parameter to above the softening temperature during the recovery process, allowing pitch fines to be melted and re-formed into particles, which enables the recovery and reuse of material that would otherwise be lost

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If petroleum pitch is heated above softening temperature for processing, then material becomes deformable for shaping, but deformation occurs prior to carbonization or graphitization

Engineering Contradiction:

Improveshaping capabilityVSAvoidshape retention

Core Design Contradiction:

Ease of manufactureVSShape

Solution Approach 1:

The patent performs preliminary shaping of pitch particles in a mold below softening temperature before carbonization, ensuring that the shape is established while the material is still rigid and will not deform during subsequent high-temperature processing

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent utilizes phase transitions by heating pitch above softening temperature only when needed for recovery and re-forming, then cooling it below softening temperature for shaping and final processing, thereby controlling deformability through temperature-dependent phase changes

Inventive Principle:

Principle #36Phase transitions

3Ease of operation

If pitch fines are disposed of as waste material, then handling complexity is reduced, but material recovery and productivity decrease

Engineering Contradiction:

Improvewaste handlingVSAvoidpitch particle recovery

Core Design Contradiction:

Ease of operationVSProductivity

Solution Approach 1:

The patent makes the system self-sufficient by recovering and re-processing pitch fines into usable particles, eliminating the need for external waste disposal processes and converting what would be a burden into a resource that enhances overall productivity

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

Instead of discarding pitch fines, the patent recovers them through melting and re-solidification processes, transforming waste material back into valuable pitch particles that can be used in subsequent carbonization and graphitization processes

Inventive Principle:

Principle #34Discarding and recovering

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 method achieves near-complete conversion of petroleum pitch into desired particles with reduced waste and improved shape retention during carbonization, enhancing the efficiency and quality of amorphous carbon and graphite production.

Implementation Method 1

heating the pitch fines at a temperature above the first softening temperature to produce a pitch melt; and combining the pitch melt with the petroleum pitch in the grinding apparatus; wherein the pitch melt hardens in the grinding apparatus

Methodology Applied

Scientific EffectPhase change (solidification): Phase Change

Implementation Method 2

heating the pitch fines at a temperature above the first softening temperature to produce a pitch melt

Methodology Applied

Scientific EffectMelting: Melting

Data Source

PatentUS20260098211A1Methods for production of pitch particles with reprocessing of pitch fines

Publication Date: 2026.04.09 EXXONMOBIL TECHNOLOGY & ENGINEERING CO

AI summary

Pitch particles may be produced by a grinding process, in which pitch fines may be recovered and recycled to a grinding apparatus as a pitch melt. Such methods may comprise: providing a petroleum pitch having a first softening temperature; grinding the petroleum pitch in a grinding apparatus below the first softening temperature to produce a plurality of pitch particles and a plurality of pitch fines; separating the pitch particles from the pitch fines; heating the pitch fines at a temperature above the first softening temperature to produce a pitch melt; and combining the pitch melt with the petroleum pitch in the grinding apparatus. The pitch melt hardens in the grinding apparatus and is reground. The pitch particles may be further stabilized by heating at a treatment temperature below the first softening temperature in an environment comprising about 1 mol % to about 20 mol % oxygen to form stabilized pitch particles.