Energy and Electricity - Introduction to Carbon Capture and Sequestration - page 33

Table 1.5.4 Comparison of students' footprints with various countries' per capita
footprints

Comparison Groups Metric tonnes of CO 2 per year per capita

Student D w/o car 5.82

Student D w/ car 9.18

USA Average* 28.6

China Average* 3.1

India Average* 1.8

World Target to Combat
Climate Change

2

Source : Hertwich et al . [1.15].

average, they are still higher than the world target to combat climate
change [1.15].

A concrete solution to carbon capture

Question: How much CO 2 can we capture if we use it as a source of concrete?

Solution: Samuel Taft Schloemer, Lingchen Fan, and Joseph Jung-Wen Chen.

Figure 1.3.1 shows that carbonate is the most stable form of carbon.
Since carbonates are the major component of concrete, we will explore
the use of CO 2 from flue gas emissions as a source of concrete.
Concrete is a composite material made from cement, sand, aggre-
gate, and water. The cement is the binding agent, which reacts with the
water to form calcium silicates that glue together the sand and aggregate
particles. The aggregate, often composed of crushed stone, provides the
compressive strength of the material (see Figure 1.5.1 ). Cement produc-
tion is a major source of CO 2 emissions worldwide, accounting
for around 829 million metric tonnes of CO 2 , or 3.4% of all emissions, in
the year 2000. However, concrete could be a net CO 2 sink if the aggre-
gate were made of a substance that consumed CO 2 . For example, a
common aggregate is calcium carbonate (CaCO 3 ), also known as