Graforce (Use corona plasma pyrolysis to crack methane into clean hydrogen)

Graforce, a German cleantech company founded in 2012, has developed innovative methods for producing hydrogen and reducing carbon dioxide emissions. The company’s primary technology utilizes a high-frequency plasma field generated by renewable electricity to split hydrocarbons such as methane into hydrogen and solid carbon. This process is significantly more energy-efficient than traditional water electrolysis, requiring only one-fifth of the energy to produce the same amount of hydrogen.

Challenges: hydrogen fuel

Hydrogen (H₂), the most abundant element in the universe, is not just a fundamental building block of stars—it’s also a vital ingredient in the synthesis of ammonia. Ammonia production is at the heart of creating a plethora of products that we rely on daily, from the fertilizers that nourish our crops to the plastics that are woven into the fabric of modern life.

Traditionally, the world has leaned heavily on steam methane reforming (SMR) to produce over 60 million tons of hydrogen annually. However, this method comes with a significant environmental cost. It’s an energy-intensive process that contributes approximately 2% to the global carbon dioxide (CO₂) emissions, releasing between 5 and 9 tons of CO₂ for every ton of hydrogen it generates.

Graforce Technology

Graforce has developed an innovative plasma pyrolysis technology that uses a non-thermal corona plasma generated by renewable electricity to crack hydrocarbons, such as methane (CH₄), into hydrogen (H₂) and solid carbon (C). The plasma reactor developed by Graforce utilizes a single plasma electrode to generate corona discharges within the reaction chamber using a high-frequency alternating voltage. This results in a decrease in energy consumption and operational expenses, enabling the production of hydrogen at a lower cost.

How Graforce generates hydrogen from methane

The diagram below illustrates Graforce’s plasma pyrolysis reactor, which is used to convert methane into hydrogen and solid carbon.

Graforce plasma reactor cracks methane into hydrogen (ref. US20230264167A1)
Graforce plasma reactor cracks methane into hydrogen (ref. US20230264167A1).

The plasma pyrolysis system consists of several components. These include:

  • a gas-tight reaction chamber,
  • a gas supply line for introducing methane gas into the chamber through the plasma electrode,
  • a single plasma electrode that generates corona discharges using a high-frequency alternating voltage,
  • a high-frequency generator for supplying power to the plasma electrode,
  • a hydrogen discharge line for extracting hydrogen from the chamber, and
  • a solid carbon discharge line for collecting carbon particles.

The reaction chamber wall electrically insulates the plasma electrode from outside of the wall. This is achieved by coating a thin insulation layer, such as high-temperature ceramic, on the surface of the inside wall that faces the plasma electrode. In this way, the electrical flow through the surface of the outside wall to the plasma electrode is zero. The reaction chamber’s inner wall has floating potential. A stronger electric field is formed directly at the plasma electrode, which facilitates the cracking of methane.

One of the key features of Graforce’s  technology is the use of exactly one plasma electrode to generate corona discharge on the methane gas nozzle tip of the plasma electrode, which guides the hydrogen-containing gas into the reaction chamber. No return electrode is used. This has many advantages:

The use of just one plasma electrode to create a corona discharge on the plasma electrode is a key part of Graforce’s technology. No return electrode is used. This has many advantages:

  • The corona discharge generates a non-thermal plasma. When cracking methane, less energy is converted into thermal energy that cannot be efficiently reused, which can reduce energy consumption.
  • Plasmas from corona discharges can be ignited and operated at atmospheric pressure. This significantly reduces system and operational costs.
  • Using a single plasma electrode reduces contamination and possible clogging of the plasma electrode with a solid carbon by-product. Electrode material ablation is also reduced.

During operation, the methane gas is introduced into a gas-tight reaction chamber through the nozzle tip of the plasma electrode. This design allows the plasma electrode to cool without additional cooling and reduces its corrosion at high temperatures. Applying a high-frequency, high voltage to the plasma electrode produces a corona discharge, which generates a strong electric field that ionizes the surrounding methane gas. This creates a free electron and a positive ion.

Lower mass electron is accelerated much more strongly than the positively charged ion. The average electron energy in corona discharge ranges from 10 to 20 eV, which is sufficient to break the C-H bonds in methane. If several high-energy free electrons hit several atoms of a methane (CH₄) molecule, methane can be cracked into its atoms of hydrogen (H) and carbon, which undergo further reactions to form hydrogen gas (H₂) and solid carbon (C).

The electric field strength gets so weak at a certain distance from the plasma electrode that the electrons no longer have enough energy to produce additional free electrons and positively charged ions. This delimits the corona discharge and represents its outer limit.

Following methane plasma pyrolysis, hydrogen gas exits the reaction chamber. An eccentric at the bottom of the reaction chamber discharges the solid carbon, ensuring no gas enters the reaction chamber through the eccentric.

Solid carbon can form carbon structures that extend from the plasma electrode nozzle to the inside of the reaction chamber’s wall. Furthermore, the plasma electrode can become clogged with carbon buildup. Therefore, the reaction chamber also has two movable cleaning blades for removing the solid carbon accumulating on the inner wall of the reaction chamber and on the surface of the plasma electrode.

Efficiency of Graforce plasma pyrolysis reactor

The efficiency of the Graforce plasma pyrolysis reactor can reach 85%. This is higher than microwave plasma processes, such as the Kvaerner process, which operate at an efficiency of about 60%. Efficiency refers to the amount of electrical power required to produce molecular hydrogen. For example, Graforce produces 1 kg of molecular hydrogen apparatus using 10 kWh. The Kvaerner process, however, requires 13.75 kWh per kg of H₂.

Furthermore, in contrast to microwave plasma processes, the Graforce plasma pyrolysis reactor is not necessary to operate under reduced pressure to produce hydrogen.

Graforce hydrogen generation system

The diagram below shows how to arrange two plasma pyrolysis apparatuses consecutively in series to completely convert methane into hydrogen.

Graforce plasma reactor system cracks methane into hydrogen (ref. US20230264167A1)
Graforce plasma reactor system cracks methane into hydrogen (ref. US20230264167A1).

Methane gas is introduced into the first plasma pyrolysis reactor that cracks methane into molecular hydrogen and other gaseous and solid carbon by-products. The solid carbon is discharged to the reservoir, where it can be removed by means of an eccentric.

The molecular hydrogen, unreacted methane, and other gaseous by-products are sent to the downstream plasma pyrolysis reactor, where uncracked methane and gaseous by-products are further cracked into molecular hydrogen and gaseous and solid carbon by-products. The solid carbon is discharged to the reservoir.

The molecular hydrogen, unreacted methane, and gaseous by-products are sent into another reservoir. This reservoir has a membrane and a selective adsorber. The membrane can be a polymer membrane. ZSM-5 is used as the adsorber.

Unreacted methane cannot pass through the membrane and is separated from the gaseous mixture. Any gaseous by-product is adsorbed by the selective adsorber, so that essentially only molecular hydrogen is obtained.

Graforce Patent

  • US20230264167A1 Plasmalysis Apparatus For The Corona Discharge-Induced Cracking Of Hydrogen-Containing Gas
  • WO2023117752A1 Plasma lysis apparatus for corona discharge-induced splitting of solids and liquids

Graforce Technology Applications

  • Hydrogen production

The primary application is the production of green hydrogen from various feedstocks, including methane, natural gas, biogas, liquefied natural gas (LNG), liquefied petroleum gas (LPG), wastewater, liquid manure, and ammonia. The technology uses a high-frequency plasma field generated from renewable energy sources like solar or wind to split these feedstocks into hydrogen and other byproducts.

  • Decarbonization and CO₂ removal

When using biogas or biomethane as feedstock, the process indirectly removes CO₂ from the atmosphere by sequestering the solid carbon byproduct in products like steel, cement, and soil enhancement. The technology is considered the first market-ready alternative to carbon capture and storage (CCS).

  • Wastewater treatment

The plasma pyrolysis process can treat wastewater by splitting nitrogen and carbon compounds (e.g., ammonium, nitrates, amino acids) into hydrogen, nitrogen, and biomethane. The produced clean water can be returned to the water cycle, while the nitrogen can be used as an industrial gas.

  • Energy generation

The hydrogen produced can be used in hydrogen combined heat and power (CHP) units, boilers, or solid oxide fuel cells (SOFC) for CO₂-free heat and power generation.

Graforce Products

  • Methane plasmalyzer®

This product can convert natural gas, biogas, LNG, and other hydrocarbons into hydrogen and solid carbon using a high-frequency plasma field generated by renewable electricity.

  • Wastewater plasmalyzer

Treats wastewater by converting nitrogen and carbon compounds into valuable industrial gasses such as hydrogen, nitrogen, methane, and oxygen.

Graforce has built facilities in Germany and Austria that will produce up to 1.2 tons of clean hydrogen daily from natural gas and ammonia starting from May 2024.

The company collaborates with leading companies in engineering, procurement, and construction to scale modular facilities according to customer needs. Notable partnerships include collaborations with Kawasaki Gas Turbine Europe and Worley to expand the technology in the APAC region.

Graforce Founder

Jens Hanke is Founder.

Graforce CEO

Jens Hanke is CEO.

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