by Carbon dioxide (CO2) is a colorless, odorless gas that is a natural byproduct of animal respiration and plant and microbial respiration in ecosystems. It is also produced through human activities like the burning of coal, natural gas, and oil for electricity generation and transportation. The concentration of CO2 in the Earth’s atmosphere has increased by about 45% since the Industrial Revolution began in 1750. This is largely due to human activities like deforestation and the combustion of fossil fuels. The rising levels of atmospheric CO2 is a major cause of global warming and climate change.
CO2 Conversion through Chemical Processes
While CO2 is a greenhouse gas that contributes to global warming, it can also be converted into useful products and fuels through various chemical processes. One approach is carbon capture and utilization (CCU), which involves capturing CO2 emissions from large point sources like power plants and oil refineries, and converting it into synthetic fuels or other products. This helps reduce the amounts of Carbon Dioxide Utilization entering the atmosphere while also creating value-added products. Some commonly used CCU techniques are:
– Carbonation: CO2 can be bubbled into water to produce carbonic acid which is then reacted with metal oxides or hydroxides to form carbonate salts. For example, reacting with calcium oxide produces calcium carbonate.
– Syngas production: CO2 can be combined with hydrogen to produce syngas or synthesis gas through processes like gasification. Syngas is a versatile intermediate used to synthesize alcohols, gasoline and other liquid fuels via Fischer–Tropsch synthesis.
– Methanol production: Hydrogenation of CO2 yields methanol (CH3OH), which can replace gasoline as a vehicle fuel or fuel additive. It can also be used as a chemical building block or solvent.
– Polycarbonate production: CO2 acts as the carbon source to synthesize polycarbonates, a type of plastic that has diverse applications like lenses, electronic hardware and automotive components.
Carbon Dioxide Utilization Conversion using Biological Methods
In addition to chemical means, Carbon Dioxide Utilization can also be converted to fuels and chemicals using biological processes like fermentation. Key approaches here are:
– Microalgal cultivation: CO2 is consumed by microalgae through photosynthesis and converted into biomass which can then be processed into biodiesel, biogas or biogenic plastics and materials. Algal biofuels avoid competition with food crops.
– Phototrophic bacterial fermentation: Certain photosynthetic bacteria like Ralstonia eutropha and Synechocystis can fix CO2 and produce alcohols, carboxylic acids and other compounds through dark fermentation fed by light energy.
– Enzymatic catalysis: Enzymes like formate dehydrogenase and carbon monoxide dehydrogenase can catalyze transformations of CO2 into formate, carbon monoxide or other reduced carbon molecules. Further processing yields hydrocarbon fuels.
– Anaerobic digestion: In anaerobic digesters, bacteria and archaea convert biodegradable waste and sewage sludge into biogas containing methane and CO2 through fermentation. Captured CO2 can offset fossil fuel use.
Current Demonstration Projects and Market Potential
Several pilot plants and demonstration facilities worldwide are validating CCU technologies. Norwegian company ANthropic operates an algal biorefinery producing biomass, biocrude oil and fertilizer from harvested algae grown on flue gas CO2. Carbon Recycling International in Iceland makes 1 million liters per year of methanol using CO2 and renewable hydrogen. CarbonCure in Canada supplies concrete producers with CO2 that chemically bonds into the hardened concrete product. As scale-up occurs, CCU technologies offer solid prospects in various sectors with global market potential estimated in billions of dollars annually by 2030 and beyond.
While CO2 emitted from concentrated industrial sources contributes greatly to climate change, the gas can also be converted to valuable products and low-carbon synthetic fuels through chemical and biological methods. Carbon capture and utilization represents a promising approach that not only helps mitigate emissions but builds sustainable economies around captured carbon. With advancement and commercialization of emerging technologies, CCU industry has the chance to play a vital role in transitioning to more carbon-smart production systems worldwide.
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1. Source: Coherent Market Insights, Public sources, Desk research
2. We have leveraged AI tools to mine information and compile it
