Storing CO2 in products
I recently came across an article where a company claims to have developed a method for producing gasoline from CO2. This seems to be interesting at a time when researchers are working on finding ways to sequester CO2 in geological formations for economic activity like enhanced oil recovery (EOR). The other option that seems to be promising is to store carbon in products like gasoline, plastics, cement etc. This post will focus on the potential of using CO2 directly as feedstock for producing carbon containing products thereby reducing the CO2 emissions into the atmosphere.
CO2 has many industrial uses. The chemical industry uses carbon dioxide to produce fertilizers, plastics, and polymers. Some of the important products that can be produced from CO2 for which research is in various stages of development are plastics, cement, and gasoline among others.
Now let’s look at how CO2 is used as feedstock for plastics production and its associated benefits. Plastics are synthetic polymers produced mainly from crude oil. Novomer, a material manufacturing company in New York is developing a process for manufacturing plastics from CO2. It is estimated that for every 1 tonne of oil burnt, 3 tonne of CO2 is released into the atmosphere and for producing 1 tonne of plastics, 2 tonne of oil is required. So for every tonne of plastics produced, 6 tonne of CO2 is released into the atmosphere. Using the process developed by Novomer, the amount of oil required can be reduced by half as it uses only 50% fossil fuel feedstock in the form of epoxides and the remaining is sourced from the captured CO2. Hence for production of 1 ton of plastics, roughly around 1 ton of CO2 is the input required which translates into 250 Mt of CO2 as input for 250 Mt of plastics produced annually (Global plastics production is 250 Mt as of 2009).
Cement Industry is considered to be one of the largest emitter of CO2 next only to power plants. Calera, a California based company has devised a method to produce cement from CO2 and estimated that for every ton of cement produced ½ ton of CO2 is used. If all the cement produced globally is produced from CO2, 1.5 billion tonnes of CO2 would be required for producing 3 billion tonnes annually. (Global cement production is approximately 3 billion tonnes in 2009).
Gasoline is a hydrocarbon consisting of carbon and hydrogen which is derived from crude oil. A company by name Carbon sciences is developing a technology to transform CO2 to liquid fuels like gasoline, diesel and jet fuel. According to their estimate for 3.5 tonnes of gasoline produced, 1 ton of CO2 is consumed in this process. If all the gasoline consumed globally is produced by this process (which is 4 billion tonnes annually), 1 giga tonne of CO2 would be consumed during the gasoline production process.
An estimate says that the total CO2 emitted is around 35 giga tonne, of which around 40% is contributed by power plants (which is 14 giga tonnes). Suppose all of gasoline, cement and plastics produced, use CO2 as feedstock, roughly around 2.5 giga tonnes of CO2 would be required. Hence in all, 18% of the total CO2 emitted by power plants can be used for the manufacturing of products like gasoline, cement and plastics. This technique along with algae based CO2 capture and EOR using CO2 appears to be promising techniques to sequester carbon dioxide in large amounts.
You can find elaborate description of each of these techniques of storing CO2 in products here