Does a Circular Economy with Carbon Removal Need Plasma Gasification?
Daniel B. Schmidt
3/30/2024
Our collective human civilization is not sustainable using current technology. Our energy, agriculture, and industrial core are all destructive to the ecological systems we depend on. I do believe we can solve these challenges, but we must apply our most advanced science and technology to do so in the time we have. The International Panel of Climate Change scientists are telling us we must actively remove greenhouse gasses to avoid climate change from triggering irreversible loss of the polar ice caps. In their 2023 synthesis report for policymakers, the IPCC said, “At sustained warming levels between 2°C and 3°C, the Greenland and West Antarctic ice sheets will be lost almost completely and irreversibly.” (B.3.2) We must achieve 100% clean energy while simultaneously making our agriculture and industry carbon-negative. Many leaders are now describing the concept of a circular economy to eliminate pollution. This is modeled after natural systems that recycle air, carbon, water, and nitrogen among other elements in endless living cycles. It is possible for us to perfectly recycle materials using plasma gasification to reduce materials to their elemental form and then be able to harvest those building blocks to make new products. In this way, we can use clean electricity to eliminate all pollution from industry and transform the ethanol industry into carbon-negative chemical manufacturing. Does a circular economy with carbon removal need plasma gasification? There may be other technologies that can better serve this role. I intend to explore whether plasma gasification is capable of eliminating waste streams in tandem with carbon removal. Then discuss how a circular economy could utilize carbon removal with plasma gasification. Finally, I will further explore whether other technologies are better suited to meet our needs of eliminating pollution while balancing the electric grid with 100% clean energy.
The process of plasma gasification involves controlled electric arcs that reach temperatures near to those at the surface of the sun. Plasma gasifiers are used to destroy waste streams and biomass without combustion through a process known as pyrolysis or molecular dissociation. This means that the molecular bonds are essentially ripped apart rather than a reaction like combustion with CO2 and H20 as a product. In his paper published in The Journal of Cleaner Production, Kuo (2021) said, “Efficient utilization of waste-derived fuels such as municipal solid waste (MSW) and refuse-derived fuel (RDF) as a potential source to produce renewable energy and chemicals is a promising eco-friendly technology in the circular economy transition for green and sustainable growth.” (p. 1). Biomass and waste streams are largely made of carbon and hydrogen-based molecules so when they go through a plasma gasifier Hydrogen and Carbon Monoxide are produced. These are valuable feedstocks in chemical manufacturing and can also be used directly as a form of long-duration energy storage. The infrastructure to transport and handle these molecules already exists for natural gas. Blends of these carbon-neutral gasses can decarbonize the natural gas industry as a direct substitute. PFAS is a petrochemical product known as a forever chemical that will not break down in the environment and is continuously being added to our environment by industry. It is possible to filter it out at wastewater treatment plants and through concentration in biomass using regenerative agriculture co-located with solar projects in what is being called agrivoltaics. Using this biomass as a molecular ingredient in chemical manufacturing instead of food is important because PFAS concentrated by biomass is poisonous despite currently being widespread across the farmlands. Chemical manufacturing using syngas via plasma gasification destroys hazardous and unsorted waste streams while producing carbon-negative products in a circular economy.
If this syngas is used to manufacture durable products then the carbon will be locked into a durable molecular bond preventing it from forming CO2 in our atmosphere. In the Journal of Waste Valorization article Xu (2021) said, “The use of biomass as a feedstock in the production of power, fuels, and other chemicals has attracted increasing attention due to its low or even negative CO2 emission, which is important as a major step for mitigating the global climate change.” (p. 1364) Carbon in the syngas originates from the atmosphere. Biomass via photosynthesis is a perfect vehicle to concentrate CO2 into a form that can then be removed from the carbon cycle by plasma gasification making it available to replace conventional petrochemical inputs for products that keep the carbon out of the atmosphere for a long period of time. Waste heat from plasma gasification could be used to produce biochar with more opportunities to layer value into integrating systems that create emergent value through symbiotic relationships. The elements prevalent across all of earth in the form of air and water can be used to manufacture a wide range of carbon-negative products using an abundance of solar energy. The actual consumption of that energy can be done flexibly to balance the grid through demand response programs and smart load controllers. Large industrial park microgrids can serve to stabilize the grid while also being capable of islanding to be a self-supporting industrial park microgrid. This is essential for national security so that we are immune to a central grid failure. A network of microgrids will be like the Internet for energy and infrastructure and also make the Internet more resilient. The circular economy of carbon removal is essential to decarbonize industry and make it sustainable for an abundant thriving civilization, but it may not require plasma gasification to realize this potential.
Other technologies have the potential to disrupt industry and destroy pollution with clean energy. Conventional gasification can be used with most biomass sources without any need for an electrical input. This is the original source of gas for street lighting in cities. They used a device called a gasometer to capture the syngas from gasified coal that could be stored for commercial use. There are modern gasification systems that are co-located with biomass sources like lumber yards, paper mills, and other reliable sources of feedstock. These systems provide a lot of value to their application but are limited in their potential to disrupt the industry. They can be used to generate electricity, but they cannot be used to eliminate municipal or hazardous waste streams. Plasma gasification reaches a temperature capable of destroying almost anything that goes through it. There are layered systems that use a plasma torch to treat the emissions of conventional gasification. In the journal, Bioresource Technology, Shahabuddin (2020) said, “The advantages of microwave pyrolysis/gasification over conventional gasification include uniform temperature profile, ability to handle large biomass particles, cleaner product output with high heating value and cost effectiveness”(para 2.3.5) There are also other methods of using electricity to transform waste into new products like microwave gasification and flash joule heating. These methods may be more promising than existing plasma gasification technology. Both methods are likely a more efficient use of energy. Flash joule heating is being used to produce cheap commercial-grade graphene as well. Graphene will change the nature of the public discourse once products are made using carbon removal that are significantly and measurably superior to existing products.
In conclusion, plasma gasification may be a direct pathway to convert waste streams into carbon-negative products but it may not be needed for a circular economy with carbon removal technology. It is clear that the molecular economy of chemical manufacturing consumes carbon inputs to make products and that carbon can be removed from the atmosphere by biomass. Syngas via biomass and waste stream gasification is a viable pathway to replace fossil fuel sources of carbon. However, this does not require plasma gasification. Perhaps the most promising method is flash joule heating to produce what has been termed flash graphene. A small electric arc can be used to pyrolyze carbon-based materials from waste streams and biomass to produce very valuable high-quality cheap graphene that can be used to make stronger, more flexible materials and advanced energy technologies. In the article, A Scientific Machine Learning Framework to Understand Flash Graphene Synthesis, Sattari says, “The generated high temperature (>3000 K) breaks the chemical bonds and reorganizes the carbon atoms into thermodynamically stable sp2 -hybridized graphene sheets.” (p. 1209) Conventional gasification, microwave gasification, and flash joule heating are all other methods of converting biomass and waste streams into feedstocks to supply industry with a carbon-neutral source of syngas and other carbon products like graphene and biochar. The benefits of these other processes can meet the needs of different sectors of the economy while plasma gasification excels at processing large volumes of hazardous and mixed municipal waste streams. Regenerative agriculture can supply a diverse range of biomass inputs to a carbon removal circular economy using gasification that replaces the ethanol industry as electric vehicles reduce the need for gasoline. Considering that electric vehicles use a large amount of graphite in their batteries and that new manufacturing for domestic energy storage capacity is being developed, there is a need for new sources of graphite and other materials to make batteries. Conventional gasification as well as waste heat from plasma gasification can produce biochar that can be further processed into high-quality graphite. Further research is needed and demonstrations of circular economies using these different techniques must be explored to validate that it is both feasible and economical to scale this technology to widespread adoption. The petrochemical industry and hard-to-abate sectors have a lot to gain from this technology in order to meet their decarbonization targets and they possess the resources and technology to fully implement it. At this point, it is just a choice we are making to allow the petrochemical industry to remain unsustainable and risk the future of life on Earth and humankind. It may require that new industry leaders emerge to meet the challenges of our moment in history.
References
Kuo, P.-C., Illathukandy, B., Sun, Z., & Aziz, M. (2023). Efficient conversion of waste-to-SNG
via hybrid renewable energy systems for circular economy: Process design, energy, and environmental analysis. Waste Management (Elmsford), 166, 1–12. https://doi.org/10.1016/j.wasman.2023.04.041
IPCC. (2023). Synthesis report of the IPCC sixth assessment report (AR6) summary for
policymakers. In IPCC. Intergovernmental Panel on Climate Change.
Sattari, K., Eddy, L., Beckham, J. L., Wyss, K. M., Byfield, R., Qian, L., Tour, J. M.,
& Lin, J. (2023). A scientific machine learning framework to understand
flash graphene synthesis. Digital Discovery, 2(4), 1209–1218.
https://doi.org/10.1039/d3dd00055a
Shahabuddin, M., Alam, M. T., Krishna, B. B., Bhaskar, T., & Perkins, G. (2020). A review on
the production of renewable aviation fuels from the gasification of biomass and residual wastes. Bioresource Technology, 312, 123596–123596. https://doi.org/10.1016/j.biortech.2020.123596
Xu, D., Tong, A., & Fan, L.-S. (2021). State of Scale-Up Development in Chemical Looping
Technology for Biomass Conversions: A Review and Perspectives. Waste and Biomass Valorization, 13(3), 1363–1383. https://doi.org/10.1007/s12649-021-01563-2
Isthmus Evolving 