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Renewable Energy
Published in Chitrarekha Kabre, Synergistic Design of Sustainable Built Environments, 2020
Chemical energy is stored in the bonds of atoms composing the molecules. Chemical processes requiring energy (heat) supply are termed ‘endothermic,’ those that release energy are termed ‘exothermic,’ and those that neither require heat nor release energy are termed ‘thermoneutral.’ Fuels like biomass, coal, natural gas, and petroleum are examples of high chemical energy content that can be released by combustion (an exothermic process). The process starts with little heat input (ignition), but then the process is self-sustaining, for example, when the wood is combusted in a fireplace or gasoline is burned in the car’s engine. The chemical energy in coal is converted into electrical energy at a power plant. The chemical energy in a battery can also supply electrical power using electrolysis.
Carbons as Supports for Catalysts
Published in Qingmin Ji, Harald Fuchs, Soft Matters for Catalysts, 2019
Shenmin Zhu, Chengling Zhu, Yao Li, Hui Pan
The growing unbalance of carbon circulation between the atmosphere and the crust surface is mainly resulted from the consumption of fossil fuels, which gives rise to the global warming and the unsustainability of petrochemical industry. Solar generation provides a clean and promising strategy to solve those energy problems, i.e., photocatalytically reducing CO2, coverting the primary products from fuel combustion and the greenhouse gas into fuels like CO, CH4, CH3OH or raw monomer materials like HCOOH and HCHO [93–95]. This strategy can simultaneously decrease greenhouse gas and directly convert solar energy, the most abundant and renewable but low-grade energy source, to highgrade and processable chemical energy.
Fossil Fuels versus Biofuels
Published in Sonil Nanda, Prakash Kumar Sarangi, Dai-Viet N. Vo, Fuel Processing and Energy Utilization, 2019
Kang Kang, Mingqiang Zhu, Guotao Sun, Xiaohui Guo
Fossil fuels have been explored and used extensively for many centuries, and consumption became particularly intensive after the industrial revolution, which occurred in the late eighteenth and nineteenth centuries. Currently, the major contributors of fossil energy include coal, oil, and natural gas (Armaroli and Balzani 2011). The chemical energy stored in the hydrocarbons of fossil fuels has been utilized in various ways (e.g., in the direct combustion for generating heat or power, in the conversion to other value-added chemicals, or in further conversion to industrially relevant products by physiochemical or biological routes). Despite its increasing demand, many are criticizing the fossil fuel-based energy system due to the concerns over depletion of resources, pollution problems, rising fuel prices, and increasing political concerns (Luque et al. 2008; Nanda et al. 2015). One of the most severe issues is the emission of greenhouse gases related to fossil fuel burning in developed and developing countries (Chavez-Rodriguez and Nebra 2010). The industries have explored and implemented many types of alternatives including hydropower, solar, wind, geothermal, wave, and biomass that could potentially mitigate the greenhouse gas emissions with low carbon footprints (Panwar et al. 2011; Nanda et al. 2017b).
Effect of particle size on thermal decomposition and devolatilization kinetics of melon seed shell
Published in Chemical Engineering Communications, 2019
Awwal Ahmed, Eyitayo Amos Afolabi, Mohammed Umar Garba, Umaru Musa, Mohammed Alhassan, Kariim Ishaq
Thermochemical conversion routes include combustion, gasification, pyrolysis, cofiring, and liquefaction. All these processes result into breakage of bonds between the adjacent carbon, hydrogen, and oxygen molecules to release the stored and chemical energy. Pyrolysis (devolatilization) as a thermochemical conversion process is one of the first steps of combustion, gasification, and liquefaction processes (Nithitorn et al., 2015; Garba et al., 2017b). The yields of liquids, char, and gases obtained from biomass pyrolysis process are dependent on the feedstock type, particle size, heating rate, temperature, and residence time The size and the mass of particles are some of the most important parameters that is profoundly influenced by the heat and mass transfer limitations. The larger the particle size, the more effective the heat transfer causing the release of more volatiles. Several studies reported the effect of different particle sizes of various biomass materials on char, liquid, and gas yield (Demirbas 2004; Mani et al., 2010).
Performance analysis of vortex flow through a swirler by computational fluid dynamics technique
Published in International Journal of Ambient Energy, 2020
Combustion is a physical and chemical process in which chemical energy converts into thermal energy. This phenomenon always follows some chemical reaction in a form as below: This above reaction form is a form of exothermic reaction in which a group of reactants are reacting with each other and forming a stable and less chemical energetic substance with some amount of heat or thermal energy. The relation of these energies can be clearly observed by the following graphical plot.