Plasma is popping up in all kinds of places in the cleantech world. We’ve long seen its application in electric arc furnaces and it’s also essential in nuclear fusion. Hydrogen plasma technologies are under development for iron ore reduction, and now we are seeing its potential application in chemicals production.

Plasma is the fourth state of matter after solids, liquids, and gases and is produced when you heat up a gas. It’s what the sun is made of, and it appears in the sky as the aurora borealis.

Plasma and Chemicals Production

Molecules in a plasma state react more readily than in a gas, so the energy needed for a chemical conversion is less. The same principle applies to hydrogen plasma reduction of iron ore.

This is increasingly important as the chemicals industry attempts to address emissions. Nearly a gigaton of emissions result from producing heat for chemicals processing, and the use of renewable energy to generate heat (plasma or other approaches) can help address these emissions.

How Does it Work in Practice?

Most approaches use cold plasma technology. Feedstock is injected into a reactor where electricity is used to produce plasma. The plasma reactor separates feed into molecules and radicals.

The increased reactivity caused by the plasma enables the direct conversion of feedstock into product – without the use of additional heat. The process achieves high efficiency conversions since molecules react more readily and under non-equilibrium conditions, e.g., low temperature.

Currently, application development has targeted reduction of carbon dioxide (CO₂) to carbon monoxide (CO), which can be combined with hydrogen to produce syngas — an important building block used in the chemical industry to produce methanol as well as e-fuels. 

The reverse Water Gas Shift (rWGS) reaction is a process that converts carbon dioxide and hydrogen into water and other products. The rWGS reaction produces syngas, which can be used to create a variety of high-value chemicals. 

This translates to significant energy savings. Syngas made from green hydrogen and reduced CO reduces energy requirements by 30% or more compared to green hydrogen combined with rWGS. There is also a significant savings in CAPEX. If syngas were applied to methanol or e-fuels production, this could realize significant cost savings.

What Can Plasma Processing Be Used For?

Several start-ups are developing technologies for plasma processing with a focus on reducing costs of sustainable chemicals production including e-jet, methanol, ethanol, ethylene, and acetylene.

• D-CRBN is a developer of plasma technology for the production of CO from CO2.  The company recently announced a pilot project with Arcelor Mittal where captured carbon dioxide (CO2) is reduced to carbon monoxide (CO) – which can be recycled and used as an iron ore reducing agent in the blast furnace (e.g., in place of coke).
  
• Refuel Green, who makes plasma-catalysis reactors for syngas productions, raised $1.3M in pre-Seed funding in 2023. The start-up has developed a first prototype to produce CO, which will be used to produce e-fuels. Scaled prototypes will follow from 2024 with series production of reactors expected by the end of 2025.
• EnaDyne, a provider of plasma catalysis technologies for hydrogen production, is a start-up in Greentown Labs’ Carbon-to-Value Initiative, and is currently developing a pilot plant for its cold plasma technology. EnaDyne is targeting multiple products including methanol, ethanol, and ethylene.
• Thoriant, a recent spinout from Brightsite PlasmaLab, focuses on the commercial development of advanced plasma technology for the production of emission-free hydrogen and acetylene from methane.  The company is developing a 500kW pilot to produce acetylene and hydrogen from methane, with plans for a demonstration plant from 2028.

What Does the Future Hold?

Current production of target chemicals for plasma innovators result in nearly 5% of global emissions, so the technologies which enable electrification of these processes could have a huge impact. But despite the benefits, plasma processing remains relatively nascent, and the proof of high efficiency and cost savings will be realized as the technology matures.

Like other electrically driven chemical process technologies, the cost of production is highly dependent on the cost of electricity required to drive the process. Economics will also be impacted by the effectiveness of complementary technologies — hydrogen production, methanol, or jet fuel synthesis.