Advantages And Disadvantages Of CO2

The issues of global climate change and global warming have attracted more and more concerns. It is commonly agreed that CO2 is the most important and critical anthropogenic greenhouse gas (GHG). The predicted growth of global economy and world population in the near future will lead to an increased demand for energy [1], resulting in an even further increase in the atmospheric CO2 concentration [2]. In recent years, the amount of CO2 liberated by the utilization of fossil fuels has been over 30 gigatonnes. Global GHG emissions have doubled since the early 1970s, and the emissions would double again by 2050 without appropriate and effective emission abatement. Although international attempts have been made to reduce CO2 generation by promoting

The technologies of CO2 capture from coal-derived power generation can be divided into three categories: post-combustion capture, pre-combustion capture, and oxy-combustion [7]. Nowadays, proposed methods and concepts for the post-combustion capture of CO2 have included solvent absorption, chemical adsorption (chemisorption), physical adsorption (physisorption), cryogenic distillation, and membrane separation [8,9]. Generally, CO2 adsorption can be used as a final polishing step in a hybrid CO2 capture system [10]. Adsorbents can operate via weak physisorption processes or strong chemisorption interactions [11], which depends on their surface compositions and characteristics. Solid physical adsorbents possess significant advantages for energy efficiency compared with chemical and physical absorption approaches [8]. Many physical adsorbents have been studied, including activated carbons [9,12–18], zeolites [12,19–25], and metal–organic frameworks (MOFs) [24–33]. Because CO2 capture by these adsorbents relies mainly on physical adsorption, research activities have been focused on increasing the surface area of these materials in order to achieve enhanced adsorption capacity [34]. Compared with other adsorbents, porous carbonaceous materials are especially attractive due to their moderate heats of sorption, and inexpensive preparation, and that they are not as sensitive to water vapor as the other CO2-philic

Microwave heating is unique and offers a number of advantages over conventional heating such as: (a) non-contact heating, (b) energy transfer rather than heat transfer, (c) rapid heating, (d) material-selective heating, (e) volumetric heating, (f) quick start-up and stopping, (g) heating from the interior of the material body, and (h) higher level of safety and automation [40]. Several studies have shown that microwave heating is a good alternative for carrying out the pyrolysis of biomass including oil-palm stone [41], wood [42], coffee hulls [43], waste tea [44], sawdust [45], wheat straw [46], rice straw [47], corn stover [48], oil palm biomass [49], and microalgae [50]. Generally, the differences between the microwave and conventional heating can be attributed to the different heating mechanisms (dielectric heating vs. convection and conduction) and to the occurrence of a phenomenon referred to as hot spots (sparks)