Conversion of CO2 An Overview
The utilization of CO2 in Industrial processes was developed earlier in 1880–1893s, for the synthesis of urea (Bazarov, 1870), hydrogen carbonates (Steinhauser, 2008), and the production of salicylic acid (Kolbe, 1874). Since the late 1800s the chemistry of CO from fossil carbon has been developed for the synthesis of chemicals and fuels that had its golden era in the 1900–1970s, and still it plays an important role in the production of value added chemicals and fuels. In 1970s CO2 was used as additive for synthesis of methanol with CO (Liu et. al., 2003) and used as a co-monomer for the synthesis of organic carbonates from epoxides (Tsuda, et.al., 1976). In 2013 Aresta and his co-worker describe the utilizaton of CO2 in the synthesis of value added chemicals and its perspective use at 2030, on considering the market growth for the chemicals and the new technologies (Aresta, et. al., 2013).
CO2 is one of the easily available feedstock used as a raw material for the production of many value-added chemicals and fuels, which provides a solution to reducing CO2 emission and energy supply challenges (Markewitz, et.al. 2012). The CO2 capture, utilization, and sequestration (CCUS) is a promising approach to reduce the emission of CO2. The Carbon capture and storage (CCS) is a technology which involves in reducing CO2 and fixing into a long-lived compound (Boot-Handford, et. al., 2014). However, the technical and economic barriers of CCS should be overcome before it can be utilize on a large scale. The main economic obstacles is the high cost of CCS that comes primarily from capture and compression which is about 75% of total cost of CCS (Styring, et. al., 2011).
Carbon capture and utilization (CCU) have recently started to attract great deal of attention worldwide because it can convert CO2 into valuable products, instead of permanently sequestering it. The advantages of CCU as compared to CCS are that utilization of CO2 is normally a profitable activity as the products have various applications. (Styring,et.al., 2011). CCS and CCU technology used to capture CO2 emissions from the sources such as power plants and different industrial processes, to reduce the CO2 emission. (Markewitz, et. al., 2012). In CCS, CO2 is capture and storage in a suitable place for a long-time (Metz, et.al., 2005, Weisser,2007, Hertwich, et.al.,2008, Cooper,2009, Nagashima, et.al., 2011, Zapp, et.al., 2012), while in CCU, CO2 is capture and converted into various useful products (Styring, et.al., 2011, Markewitz, et.al.,2012). Different CCS and CCU options are summarized in Figure 1 and described below.
Figure 1. Different technology for CO2 storage and utilization