A Study on Bicarbonate Production by Boiler's Flue Gases CO2 Condensation for Algae Culturing and Biofuels Production

Abstract

Abstract Reduction of green house gases (GHGs) emissions from the combustion of fossil fuels, such as coal, petroleum products and natural gas is a big Challenge. Especially, CO2 due to its role in global climate change. Industrial boilers are considered to be one of the largest stationary sources of CO2 emissions in oil and gas (O&G) industries(J.C.M. Pires.et al., 2012). These emissions from boiler's stack represent the highest ratio of the boiler losses because of the heat carried out by hot combustion products (nitrogen, carbon dioxide, sulfur oxide and excess oxygen). The high amount of energy wasted by dry flue gases depends on the amount of water vapor loss. The amount of wasted energy depends on final boiler exhaust temperature and mainly the hydrogen content of the fuel which ranges from 4 to 11%, depending on the type of fuel.One potential way to reduce this emission is to capture, transport and store CO2 either in geologic or oceanic formations. In addition, storage of CO2 in geologic formations could lead to new environmental issues such as threat of CO2 leakage, or potential contamination of ground water(Dennis Y.C.Leunga.et al., 2014). Biomitigation is an ideal and sustainable alternative solution for CO2 capture and recycle (CCR) by using microalgae. Using algae, as a source of biofuels offers many advantages over traditional biofuel crops including the potential to be grown on the marginal land, use of water sources which is not suitable for agriculture because algae can tolerate high salt content. Meanwhile, they sustain high growth rates, and relatively high lipid content. In fact, using captured CO2 to grow microalgae is limited by the high cost of CO2 capture technologies and utilization(Liam Brennan.et al.,2010). Moreover, algae grow poorly at night, as CO2 cannot be temporarily stored until sunrise. Therefore, the condensation of CO2 from flue gasses in the form of bicarbonate (HCO-3) solution would provide a superior alternative for CO2 delivery as feedstock for algae culture system (Van Den Hende et al., 2012.)Furthermore, it reduces CO2 emissions significantly up to 80%, and reduces the use of fossil fuels by improving the efficiency of boilers. In addition, transport and storage of the aqueous bicarbonate solution costs less than for that of compressed CO2.