Overview of Solid Fuels Combustion Technologies

Abstract

Energy drives human life and is crucial for continued human development. It is the convertible currency of technology. Without energy the whole fabric of society would crumble. Global demand for energy is rapidly increasing with increasing human population, urbanization, and modernization. This growth is projected to rise sharply over the coming years in developing countries. The world heavily relies on fossil fuels to meet its energy requirements -oil, gas, and coal are providing almost 80% of the global energy demands. Oil and natural gas prices are continuously rising, due to the rapid worldwide increase in their consumption. Coals, covering about 65% of the proven fossil fuel reserves and being widely distributed throughout the world, provide stability in price and availability and will therefore play a major role in the global energy system in the coming decades. Furthermore, given the energy crisis, the development and use of renewable energy sources is one of the key challenges in the shorter and medium term to substitute fossil fuels, to provide commercially attractive options for meeting specific energy service needs, and to mitigate greenhouse gas emissions. Biomass, including all kinds of materials that were directly or indirectly derived not too long ago from contemporary photosynthesis reactions, such as vegetable matter and its derivatives, is a widely dispersed, naturally occurring carbon resource with great energy potential. It is also considered as a CO 2 -neutral energy source. The simple act of burning biomass to obtain heat and often light is one of the oldest biomass conversion processes known to mankind.Thus, the study of coal and biomass combustion for power generation or heating processes is of extreme importance, if we are to conserve our sources of energy, while achieving the required environmental goal efficiently and reliably in a world of increasing population and energy needs. This chapter provides a survey of the technologies that are either available or are being developed to enable all solid fuels to be used cleanly and with greater amenity.

Mechanism and Kinetics of Pyrolysis of Coal With High Ash and Low Fixed Carbon Contents

“…Migliavacca [17] suggested a detailed kinetic model, which describes the devolatilization process of solid fuels under pyrolysis conditions. The thermal behaviors of coal/biomass blends [18][19][20][21][22][23] and biomass samples [24][25][26] on pyrolysis have been investigated by Vuthaluru [22] and co-authors using a thermo-gravimetric analysis (TGA) apparatus. Vamvuka [26] studied the kinetic parameters and the main devolatilisation characteristics of three biomass materials, namely, olive kernel, forest, and cotton residues.…”

The Effect of Modifiers and Method of Application on Fine-Coal Combustion

“…The latter type, taking place in a fluidized bed, is a process in which suitably prepared solid particles are suspended in a uniformly distributed upward flow of the fluid. These are high efficiency devices, capable of attaining heating capacities as high as 135 tons of steam per hour [13].Stoker furnaces are the oldest and the most commonly used devices for industrial coal bed combustion. In these devices, crushed coal (typically, 95% particles below 32 mm and 20% to 60% below 6 mm) is fed onto the stoker where primary air flows upward through the coal bed.…”

“…In the pulverized-coal furnaces, the coal is taken along with the flowing air. In the cyclone furnaces, the coal particles whirl in the air flow [13].In the pulverized-coal furnaces, the whole furnace capacity is used for the combustion of solid fuels. Coal is ground to fine particles before being mixed with air and combusted in the flue gas flow.…”

“…The latter type, taking place in a fluidized bed, is a process in which suitably prepared solid particles are suspended in a uniformly distributed upward flow of the fluid. These are high efficiency devices, capable of attaining heating capacities as high as 135 tons of steam per hour [13].…”

“…In the pulverized-coal furnaces, the coal is taken along with the flowing air. In the cyclone furnaces, the coal particles whirl in the air flow [13].…”