AUTOMATED PULSE JOULE EXCITATION FOR RAPID CONVERSION OF COMPOSITE PLASTIKOS INTO PULSED GRAPHENE

Abstract

Plastic waste poses significant environmental and health challenges, demanding sustainable solutions. This invention introduces a method for converting plastic waste into high-quality Pulsed Graphene (PG) through the Flash Joule Heating (FJH) method. The process uses a high-voltage electric discharge to rapidly heat plastic waste, producing graphene in under a second. The method operates efficiently with energy consumption as low as 7.7 KJ/g for DC-FJH, without the need for a catalyst. It represents a scalable, eco-friendly solution for reducing plastic waste while producing valuable graphene for use in industries such as electronics, energy storage, and coatings. This project aligns with SDG Goals 13, 15. and 12, offering a practical approach to addressing global waste and sustainability challenges.

Specification

FIELD OF THE INVENTION
This invention lies at the intersection of environmental sustainability, materials science,
and nanotechnology. It focuses on the conversion of plastic waste into high-quality
Pulsed Graphene (PG) using Flash Joule Heating (FJH) technology. The process offers
an efficient and scalable solution for plastic waste management and graphene
production, aligning with global efforts to address environmental concerns under SDG
Goals 13 (Climate Action), 15 (Life on Land), and 12 (Responsible Consumption and
Production).
BACKGROUND OF THE INVENTION
1. Luong, D. X., and Tour, J. M. et al. (2020), presented a novel technique for
creating flash graphene (FG) at the gram scale from low-cost carbon sources like
coal, petroleum coke, and plastic waste utilizing flash Joule heating method.
This technique doesn't require solvents, furnaces or reactive gasses and
produces turbostratic graphene with lower defects. Its yield ranges from
80-90%, depending on the carbon content presented on the input source. Flash
Graphene is energy-efficient and ideal for use in bulk composites for plastic,
metal, concrete, and building materials.
2. Zahid, M., and Abuzairi, T. (2024) ,examined the environmentally friendly
production of graphene by using pencil leads as the main source in the Flash
Joule Heating (FJH) process. Different Voltages and different grades of lead 6H,
4B, and 14B, were used to analyze the quality of graphene. Raman spectroscopy
demonstrated considerable structural changes, particularly in defect density and
layer stacking. Interestingly, at 400V, the 14B lead showed a significant decrease
in flaws and an increase in crystallite size, indicating in situ annealing. This
work presents a scalable and environmentally benign way of producing
graphene.

3. Chen, W., and Tour, J. M. et al. (2021), used Flash Joule Heating method to
create fluorinated carbon allotropes, such as concentric carbon, turbostratic
graphene, and fluorinated nanodiamonds. Their millisecond precision allowed
them to produce fluoride precursors and organic fluorine compounds without the
need for solvents. Phase development and electronic state alterations were confirmed across allotropes by spectroscopic investigation. In order to address
production issues with fluorinated carbon materials, this study reveals a tunable
correlation between product composition and flash time, which may find use in
the development of improved carbon-based materials.
4. Wyss, K.. M., and Tour, J. M. et al. (2022) developed a process to upcycle
end-of-life vehicle waste plastic (ELV-WP) into flash graphene (FG) using flash
Joule heating (FJH). This solvent-free method does not require sorting or
separation of plastic types. The resulting graphene was shown to improve the
mechanical and acoustic properties of polyurethane foam (PUF) composites.
Additionally, the FG-enhanced composites can be upcycled back into graphene,
promoting sustainability. A life cycle assessment demonstrated significant reductions in energy use and environmental impact compared to traditional
graphene synthesis methods.
OBJECTIVES OF THE INVENTION
1. Upcycling of Plastic Waste: Contribute to environmental sustainability and the
reduction of plastic waste by establishing a sustainable and effective method for
converting plastic refuse into a valuable product known as Pulsed Graphene.
2. Automated and Scalable Production: Develop and execute a fully automated
system that is capable of producing Pulsed Graphene on an industrial scale while
maintaining safety and efficiency.
3. Energy Efficiency: Optimize the flash joule heating method to produce greater
production rate and with higher purity level and less consumption of energy.
4. Wide-Ranging Industrial Applications: Enhance the sustainability & efficacy of
products and can be applied to a variety of industrial applications, including
aerospace, automotive,electronics, energy storage, and advanced coatings.
SUMMARY OF THE INVENTION
The proposed technique is an innovative solution for converting a plastic waste into
high-quality turbostratic Pulsed Graphene (tPG) using a two-step Flash Joule Heating
(FJH) method. This method comprises both Alternating Current Flash Joule Heating
(AC-FJFl) and Direct Current Flash Joule Heating (DC-FJH) processes. The powdered
plastic waste is mixed with Carbon Black powder (CB), and is placed between tungsten
electrodes within a quartz tube.
In the first phase, AC-FJH is applied to eradicate volatile components and carbon
oligomers from the mixture form, consuming 21 KJ/g of energy and followed by a short
DC-FJH pulse is then used to improve the quality and structure of the graphene, using
7.7 KJ/g of energy. This leads to production of turbostratic Pulsed Graphene (tPG).
This invention is scalable, sustainable, energy-efficient, and environmentally
friendly.This technology can be applied to a variety of industrial applications, including
electronics, energy storage, and advanced coatings, because it is scalable,
energy-efficient, and ecologically benign. This technique not only converts the waste
product into a valuable one and also results in plastic waste reduction
DETAILED DESCRIPTION OF THE INVENTION
l. Plastic Waste preprocessing:
The cleaned mixed plastic waste is collected and grind into fine particles
with a particle size of 1.1-2.3 mm, which is optimal for high-yield Pulsed
Graphene production. The plastic particles are then mixed with Carbon Black
powder or previously synthesized Pulsed Graphene to increase its electrical
conductivity and to make a conductive mixture.
2. Flash Joule Heating Process:
The conductive mixture is packed between two tungsten/copper
electrodes inside a quartz tube and the resistance between the electrodes through
the sample is adjusted to be around 1.8 - 2 ohms.This setup is known as the
''Reactor". The Reactor is placed inside a Vacuum chamber. The air inside the
chamber is pumped out using a vacuum pump resulting in the decrease of air
pressure to about 0.00999 atm. The pressure is initially lowered and vacuum is
made to form inside the chamber to prevent expelling out of the sample particles
due to the pressure difference which would occur due to the sudden increase of
temperature.

o AC-FJH Process: A voltage of 220V (50Hz) is then applied for
approximately 7.8 seconds, heating the sample to over 3000K. Due to
the sudden rise in temperature and at this temperature the Carbon-Carbon
bonds break and while the reactor is suddenly cooled the broken carbon
bonds recombine itself forming Graphene Structures. This process
releases carbon oligomers and light hydrocarbons in minimal quantities,
forming Pulsed Graphene between the electrodes but the graphene
obtained by this is poor in quality.

DC-FJH Process for Enhancement: Following the AC-FJH process, a
short DC-FJH pulse (lasting 35-55 milliseconds) is applied to improve
the structure and quality of the graphene. To achieve this, a capacitor
bank of 40,000 microfarad (250V) is made and charged to store energy
of about 1.265 kJ (for a flashing sample of I50g). When this energy is
discharged inside the quartz tube, the temperature rises to about 3500K,
during which the poorly formed Pulsed Graphene and unreacted sample
get reacted and once again result in the breaking of their bonds. But here
the reaction time is very less and due to rapid cooling the bond formation
results in Graphene structures which is the preferred one. The DC-FJH
enhances the turbostratic structure of the graphene, referred to as
ACDC-tPG.
3. Optimization Factors:
o The key factors influencing the yield and quality of Pulsed Graphene and
our optimization include:
■ Voltage: 220-230V
■ Temperature: > 3000K for AC-FJH and 3500K for DC-FJH
■ Electric current: 1-2A
■ Reaction time: 35-55 ms for DC-FJH
■ Resistance between electrodes: 1.8-2 ohms
n Particle size of plastic powder: 1.1-2.3 mm
■ Radiative cooling rate: optimized by reducing the thickness of the
quartz tube.
4. Automated System:
o Our innovation lies not only in optimizing the process for converting
mixed plastic waste into graphene but also in developing an autonomous
conversion system with enhanced safety features. The automated system
includes,
■ Controlling and monitoring the overall process flow with a
Master Controller along with relay modules and sensors.

■ Controlling the rate of charging and discharging of the capacitor
bank at the desired point of time.
■ Monitoring and regulating the voltage, current, temperature and
the amount of energy stored in the capacitor bank along with auto
cut-off features and overvoltage protection circuits.
■ Automated vacuuming of the chamber and monitoring of the
pressure inside and outside the chamber ensuring safer pressure
differences.
■ Kill Switch for emergency shutting down of the system


5. Characterization and Quality Control:
o The Pulsed Graphene produced is characterized using Raman
spectroscopy, focusing on peak ratios and bands to ensure high-quality
turbostratic graphene. The process parameters are adjusted to maximize
yield and maintain consistent quality across different batches.


6. Environmental and Economic Impact:
o The FJH method offers an eco-friendly alternative to traditional plastic
disposal and graphene production methods. By converting plastic waste
into valuable graphene, the process supports sustainable waste
management and provides economic benefits, particularly in
communities where plastic waste is a significant issue and the graphene
produced has a wide range of applications in various industries.
BRIEF DESCRIPTION OF DRAWINGS:
Fig 1: AC-FJH Circuit Diagram
The Circuit diagram depicts an electrical circuit involving a quartz tube containing a
copper electrode with one end as cathode which is connected to the negative terminal
of the 2 PIN Connector and another end as anode connected to the positive terminal of
the 2 PIN Connector. A 2-pin connector links the quartz tube to the external circuit. A
breaker box is included for safety, ensuring the system can cut off power in the event of
an overload. This setup is designed for controlled energy interactions between the
electrodes.
Fig 2: DC-FJH Circuit Diagram
The circuit diagram shows a system where an AC power supply feeds a quartz tube
containing a carbon source and an electrode. The AC is rectified using a bridge rectifier
(K.BPC5010) and filtered by four capacitors (C1-C4, each 10pF) and stored as an
electrical energy of 1.265 KJ. A control switch, resistor (22kH), and an insulated-gate
bipolar transistor (1GBT) are used to regulate the circuit. The IGBT is connected to a
20V battery, controlled by a push switch. The system allows for controlled electrical
energy flow between the carbon source and electrode.
Fig 3 & Fig 4: Basic 3D-Design
The image shows a Flash Joule Fleating (FJH) setup, featuring capacitors connected in
parallel, a graphite sample holder for material processing, and a wiring system. The
capacitors store and discharge electrical energy to rapidly heat carbon-based materials,
enabling their conversion into graphene. A power source charges the capacitors, while a resistor ensures controlled current flow during the process. This setup facilitates quick
and efficient material transformation into graphene.
Fig 5: Process Overflow
This image is a detailed block diagram of an automated control system used for a
high-voltage experimental setup, likely involving a reactor and a vacuum chamber. The
system consists of various components that are monitored and controlled using a central
Microcontroller (MC). The MC plays a critical role in managing the system by
receiving feedback from multiple sensors and sending control signals to different
actuators.
1. Sensors and Feedback Loops:
Voltage Sensor: Monitors the voltage across the capacitor bank.
3^ Temperature Sensor: Tracks the temperature within the reactor.
> Pressure Sensor: Monitors the pressure inside the vacuum chamber.
The feedback, from these sensors is transmitted to the MC for real-time data
monitoring and decision-making.
2. Microcontroller (MC):
This is the core processing unit that receives feedback from sensors and sends control
signals to various system components like the power supply, relay, and contactor. The MC ensures smooth operation by adjusting system parameters based on feedback.
3. Power Supply, Relay, and Contactor:
The power supply provides energy to the capacitor bank, which is controlled by
a relay and contactor. The relay functions as a switch to control the contactor. In turn the
contactor controls the flow of high voltage and high energy DC signals to the vacuum
chamber and reactor system.
4. Capacitor Bank:
This bank stores high-voltage DC energy and delivers it to the reactor. The
stored energy is crucial for conducting controlled high-energy Flash joule heating within
the vacuum chamber.
5. Reactor and Vacuum Chamber:
The reactor performs the Flash Joule heating process, with the vacuum chamber
maintaining specific pressure conditions required for the process.
6. Vacuum Pump:
This component is used to create vacuum inside the chamber and to regulate the
vacuum pressure continuously inside the chamber throughout the process.
7. Safety Features:
Kill switches are placed at critical points to immediately shut down the reactor
and capacitor bank in case of emergencies.
8. Display:
A digital display interface shows real-time system parameters, such as voltage,
energy, temperature, and pressure, allowing for monitoring and adjustments.



CLAIMS
We claim,
l. A method for converting plastic waste into Pulsed Graphene, comprising:
o Preprocessing plastic waste by grinding it into fine powder form with a
particle size between 1.1-2.3 mm.
o Mixing the plastic waste with conductive material, such as Carbon Black
powder or previously synthesized Pulsed Graphene, to act the mixed
form as a conductive mixture.
o Subjecting the mixture to an Alternative Current Flash Joule Heating
(AC-FJH) process at a voltage of 220-230V for 7.8 seconds which
results in raising the temperature of the sample to approximately 3000K.
to initiate the formation of Pulsed Graphene.
2. The method of claim l, wherein the mixture is packed between tungsten or
copper electrodes, and the resistance across the electrodes is maintained between-
1.8 - 2 ohms to optimize the yield of Pulsed Graphene.
3. A method for enhancing the quality of Pulsed Graphene produced by AC-FJH,
comprising:
o Applying a Direct Current Flash Joule Heating (DC-FJH) pulse of 35-55
milliseconds using a charged capacitor bank with an energy discharge of
approximately l.265 kJ, raising the temperature to approximately 3500K.
o Rapidly cooling the reactor to form turbostratic graphene, referred to as
ACDC-tPG, with improved structural properties.
4. The method of claim 3. wherein the DC-FJH process is carried out using a
capacitor bank of 40,000 microfarads (250V) to achieve the desired energy
discharge for enhancing the quality of Pulsed Graphene.
5. An automated system for converting plastic waste into Pulsed Graphene using
Flash Joule Heating (FJH), comprising:
o A Master Controller to regulate and monitor the overall process flow.
o Relay modules and sensors for real-time monitoring of voltage, current,
temperature, and pressure.

o Automated vacuum control for the reactor chamber, maintaining a
pressure of approximately 0.00999 atm to prevent the expulsion of
particles during heating.
6. The system of claim 5, wHerein the automated system includes a control
mechanism for regulating the charging and discharging of the capacitor bank,
ensuring the precise timing and energy levels required for the DC-FJH process.
7. The system of claim 5, wherein the Master Controller is configured with
overvoltage protection circuits and auto cut-off features to ensure safe operation
during the FJH process.
8. A safety system for a Flash Joule Heating reactor, comprising:.
o A pressure monitoring system for tracking pressure levels inside and
outside the vacuum chamber to maintain safe pressure differences.
o A Kill Switch for emergency shutdown, providing immediate
deactivation of the process in case of system malfunction or unsafe
conditions.

o A pressure monitoring system which is automated to trigger an alert and
halt the process if the pressure difference exceeds a predefined threshold,
ensuring the safety of the reactor.
9. A method for optimizing the Flash Joule Heating process for Pulsed Graphene
production, comprising:
o Adjusting the radiative cooling rate by reducing the thickness of the
quartz tube to improve the efficiency of rapid cooling after AC-FJH and
DC-FJH processes.
o Fine-tuning the initial resistivity across the sample by compressing the
plastic waste mixture, resulting in increased Pulsed Graphene yield.
o Monitoring and regulating the electric current between 1-2A to maintain
consistent heating and energy delivery during the AC-FJH process.
10. The method of claim 1, wherein the Pulsed Graphene produced is characterized
using Raman spectroscopy, and process parameters are adjusted based on the
analysis of peak ratios and bands to ensure consistent high-quality turbostratic
graphene across different production batches

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