Chemical Looping Combustion of Methane: A Technology Development View

Methane is a reliable and an abundantly available energy source occurring in nature as natural gas, biogas, landfill gas, and so forth. Clean energy generation using methane can be accomplished by using chemical looping combustion. This theoretical study for chemical looping combustion of methane was done to consider some key technology development points to help the process engineer choose the right oxygen carrier and process conditions. Combined maximum product (H2O？+？CO2) generation, weight of the oxygen carrier, net enthalpy of CLC process, byproduct formation, CO2 emission from the air reactor, and net energy obtainable per unit weight (gram) of oxygen carrier in chemical looping combustion can be important parameters for CLC operation. Carbon formed in the fuel reactor was oxidised in the air reactor and that increased the net energy obtainable from the CLC process but resulted in CO2 emission from the air reactor. Use of CaSO4 as oxygen carrier generated maximum energy (？5.3657？kJ, 800°C) per gram of oxygen carrier used in the CLC process and was found to be the best oxygen carrier for methane CLC. Such a model study can be useful to identify the potential oxygen carriers for different fuel CLC systems. 1. Introduction Energy demand and thus energy generation are ever increasing in many parts of the world. Carbon-based fossil fuels are the main source of energy for combustion reactions. However, the major product of energy generation using fossil fuels by combustion is CO2, and growing CO2 pollution has become a matter of serious concern amongst developed as well as developing countries. CO2 is mainly emitted from energy sector that uses coal, oil, and natural gas for combustion to generate energy for different purposes using air as an oxygen source. Although CO2 capture and sequestration is being projected as a potential option to control GHG emissions, CO2 capture technologies in-vogue are beset with several limitations including cost and energy penalty [1, 2]. Hence, these flue gases are directly vented to the atmosphere without CO2 separation and became responsible for environmental impacts of energy generation from fossil fuels, for example, global warming and climate change phenomena [3–5]. In 2010, CO2 emissions have already increased to 389.0？ppm and the burning of fossil fuels is one of the main causes for the same as reported by World Meteorological Organization [6]. This has promoted the development of clean energy technologies as a major research area worldwide. Chemical looping combustion (CLC) is an emerging clean energy technology