Opportunities for Carbon dioxide Utilization under CCUS

Global carbon dioxide (CO2) emissions from fossil fuels and industry were recorded at 34.81 billion metric tons in the year 2020. Only less than 1% of global CO2 emissions or 230 million tonnes (Mt) of CO2 are being used every year. Fertilizer industry uses 130 Mt CO2 every year to produce urea which stands at umber one user of CO2. CO2 is captured and used within the same process to produce fertiliser and ultimately released into the atmosphere. Next in line is oil and gas sector who uses around 70 to 80 Mt CO2 for enhanced oil recovery (EOR) where nearly all of the CO2 is permanently stored. In addition to fertilizer and oil & gas industries, CO2 is being used commercially in food and beverage production, cooling, metal fabrication, fire suppression and stimulating plant growth in greenhouses. Currently industries are focusing to use CO2 to produce synthetic fuel and hence we can expect to see increase in number of projects in this direction. For example, Norsk-e Fuel project in Norway is underway.

Let us explore potential uses of CO2 other than producing fertilizer and in EOR:

1) Synthetic fuels from CO2

CO2 can be converted to synthetic fuels such as methane, methanol, ethanol and aviation fuels. Government of India in its strategic direction focusing to mix 20% ethanol with gasoline to be used in transportation sector by 2023. CO2 can play an important role in producing ethanol to be mixed with gasoline and thereby in line with emission reduction strategies. However, the competition will come from other sources of ethanol production, e.g., from sugarcane. Hydrogen is used to be combined with CO2 to form different types of synthetic fuels in a highly energy intensive manner. The competition of producing synthetic fuels from CO2 will come from low carbon hydrogen as fuel which can be produced from electrolysis of water or Carbon capture and storage integrated fossil fuel combustion.

2) Chemicals from CO2

Chemicals such as plastics, synthetic rubber and fibres can be produced from CO2. CO2 is first converted to methane or methanol as the process is technologically matured. Methanol can be used as feedstock to produced other chemicals such as higher olefins, aromatics, plastics etc.

3) Building materials from CO2 and minerals

CO2 can be used to manufacture building materials such as cement and construction aggregates. CO2 reacts with calcium or magnesium to form low-energy carbonate molecules which acts as concrete. It can also be used as “CO2 curing” to replace water during the making of building materials. Presently, CO2 cured concrete formation is a mature technology. However, cement production from CO2 is at early stage of development.

4) Building materials from CO2 and waste

Small particulates used in building materials known as construction aggregates can be produced from iron slag and fly ash (waste materials from power plant and industrial processes) by reacting with CO2. Generally iron slag and fly ash are stockpiled or stored in landfill. By using iron slag and fly ash with CO2 to produce building materials will help in conventional waste disposal and thereby provide competitive edge in CO2 uses. Examples of waste materials which can be good candidates to react with CO2 to form building materials are steel slag and reduces from bauxite and air pollution control.