Electric Arc Sintering of Ceramic Proppants

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Solution Overview

Problem

The traditional method of sintering ceramic proppants using long rotary kilns is costly, has limited production capacity, and generates emissions, making it inefficient and inflexible in meeting demand for high-performance proppants.

Innovation Solution

An apparatus and method utilizing a vessel with tangential inlet and electrodes to create an electrical arc and vortex flow for sintering green pellets, allowing for rapid and efficient production of proppant particles in a selected temperature range, reducing production time and emissions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If traditional rotary kilns are used for sintering ceramic proppants, then sintering temperature can be achieved, but production time is excessively long (30 minutes to over one hour)

Engineering Contradiction:
Improvesintering temperatureVSAvoidsintering time
Core Design Contradiction:
TemperatureVSLoss of time

Solution Approach 1:

The patent replaces the traditional mechanical rotary kiln heating system with an electrical arc heating system. The electrical arc generates intense localized heat that rapidly raises the temperature of green proppant pellets to sintering temperature in seconds, eliminating the prolonged heating period required by rotary kilns while achieving the necessary sintering temperature.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the heating parameter from gradual thermal conduction in rotary kilns to intense localized electrical arc heating. This parameter change enables the temperature to reach sintering levels almost instantaneously, reducing sintering time from 30+ minutes to just seconds while maintaining the required temperature for proper sintering.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If long rotary kilns are installed to increase production capacity, then more proppants can be produced, but construction cost and lead time increase (18 to 24 months)

Engineering Contradiction:
Improveproduction capacityVSAvoidconstruction cost and lead time
Core Design Contradiction:
ProductivityVSEase of manufacture

Solution Approach 1:

The patent divides the production system into modular units where multiple electric arc sintering reactors can be operated in parallel. This segmentation allows production capacity to be increased by simply adding more independent modules rather than constructing one massive rotary kiln, significantly reducing both construction cost and lead time while maintaining high productivity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

By replacing the complex mechanical rotary kiln system with simpler electrical arc heating units, the patent enables faster deployment and lower construction costs. The electrical system requires less infrastructure, shorter installation time, and can be scaled up more economically through parallel modular units.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Temperature

If rotary kilns operate at high temperatures for extended periods, then sintering is achieved, but lower melting point metals and minerals melt and plate out, requiring shutdown and repair

Engineering Contradiction:
Improvesintering temperatureVSAvoidoperational continuity
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent uses electrical arc heating to rapidly pass through the temperature range where problematic metals and minerals would melt and plate out. By heating so quickly to the final sintering temperature, the process skips over the dangerous intermediate temperature zone, preventing deposition issues and maintaining operational continuity without shutdowns for repair.

Inventive Principle:
Principle #21Skipping (Rushing through)

Solution Approach 2:

The electrical arc heating operates in controlled periodic cycles, allowing precise temperature management that reaches sintering temperature quickly and maintains it without prolonged exposure to conditions that would cause metal and mineral degradation, thereby ensuring reliable continuous operation.

Inventive Principle:
Principle #19Periodic action

4Use of energy by moving object

If natural gas is used as fuel for rotary kilns, then sintering energy is provided, but production costs increase when natural gas price increases

Engineering Contradiction:
Improvesintering energyVSAvoidproduction cost
Core Design Contradiction:
Use of energy by moving objectVSUse of energy by stationary object

Solution Approach 1:

The patent substitutes natural gas combustion with electrical arc heating for providing sintering energy. This replacement eliminates direct exposure to natural gas price fluctuations, as electrical energy can be sourced from multiple providers and markets, potentially offering more stable and predictable production costs while maintaining the required thermal energy for sintering.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 enables rapid sintering of proppant particles in seconds, reduces production costs, and allows for scalable and flexible production capacity, overcoming the limitations of traditional rotary kiln methods.

Implementation Method 1

The electrodes are used to create an electrical arc that sinters or partially sinters the green pellets

Methodology Applied
Scientific EffectElectrical arc: Electric Arc

Implementation Method 2

The electrodes are used to create an electrical arc that sinters or partially sinters the green pellets in a selected temperature range

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 3

a gas from the tangential inlet flows along a vortex path from the first end to the second end of the vessel

Methodology Applied
Scientific EffectVortex flow: Vortex Ring

Data Source

PatentEP2971488B1Apparatus and method for sintering proppants
Publication Date: 2018.09.26 FORET PLASMA LABS LLC
  • EP2971488B1 patent drawingFigure 1A~1B
  • EP2971488B1 patent drawingFigure 2
  • EP2971488B1 patent drawingFigure 3

AI summary

An apparatus and method sinters or partially sinters green pellets in a selected temperature range to make proppant particles as the green pellets pass between an electrical arc and a gas flowing in the vortex path and exit an underflow of a vessel. The vessel has an overflow disposed in a first end, an underflow disposed in a second end, a middle portion having a circular cross-section disposed between the first end and the second end, and a tangential inlet proximate to the first end such that a gas from the tangential inlet flows along a vortex path from the first end to the second end of the vessel. A first electrode extends through the overflow and a second electrode extends through the underflow. The electrodes are used to create the open electrical arc. One or more feed tubes extend through the overflow proximate to the first electrode.