Removal of Carbon Dioxide from Flue Gas

Most of the carbon dioxide in the petrochemical industry is emitted in flue gases as a result of burning fuel oil and fuel gas. The basic problem can be illustrated by considering the combustion of a fuel gas considered as methane. 

On a dry basis, the concentration of carbon dioxide nitrogen in the flue gases will be 11.1% (1/9). However, in practice excess air is used to avoid incomplete combustion and the emission of soot from the flue stack. Excess air serves to reduce the carbon dioxide concentration. 

However, the main problem with excess air is that it introduces oxygen into the flue gas. Typical flue gas concentrations for natural gas and coal combustion in power production are given in Table 6.3. 

As well as the utility eosts shown in Table 6.4, there is the issue of compressing the flue gas to sufficient extent to be able to flow upward through the absorber against the falUng solvent. This compression cost is exacerbated by the high levels of nitrogen present. 

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Yeon S-H, Lee K-S, Sea B, Park Y-I, Lee K-H. Application of pilot-scale membrane contactor hybrid system for removal of carbon dioxide from flue gas. J Membr Sci 2005 257 156-160. 

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