Premixed LPG + Air Combustion in a Bubbling FBC with Variable Content of Solid Particles in the Bubbles

Abstract

This paper presents the results of studies on the combustion of gaseous LPG in a bubbling fluidized bed. Relationships between the temperature, the bed mass and the location of the combustion zone and the NOx and CO concentrations in exhaust gases are described. The concentrations of both gases increase with rising temperature and then quickly decline. It has been shown that despite the increase in average bed temperature the drop in the emission of nitrogen oxides is connected with lower temperatures inside the exploding bubbles. These temperatures strongly depend on the quantity of solid contained in them. The paper also presents the results of modeling the combustion process in a fuel-air bubble. The modeling carried out has shown that above the temperature at which bubble self-ignition becomes possible inside the bed, with further bed temperature rise there is an increase in the solids content inside the bubbles at the moment of explosion. As a result, the maximum temperature inside the bubbles falls and the emission of nitrogen oxides is reduced. In turn, the emission of CO is linked to the propagation of combustion between bubbles when self-ignition cannot take place inside them. Graphical AbstractComparison of experimental and calculated NOx concentration, as a function of the fluidised bed temperature Highlights1.A gaseous fuel burns in a bubbling fluidized bed2.The combustion is intermittent and takes place inside bubbles, the combustion process starts in the toroidal part of the bubble3.The NO concentration is linked to the bubble temperature, not to the bed temperature4.The solids inside a bubble affect its thermal capacity5.Consequently NO concentration falls with rising bed temperature

Sorption of Hydrogen Chloridein The Fluidized Bed Reactor

“…As shown in the earlier works dense phase of fluidized bed is made up with gaseous bubbles and an emulsion phase which contains almost the entire amount of bed material [27,28]. The average temperature of the bed of quartz sand should not exceed 1100 °C, but inside the bubble temperature reaches value about 700 o C higher than the average temperature of the solid bed material [29].…”

Cenospheric and sand fluidized bed as an environment for waste rubber combustion-comparisons of decomposition dynamics and flue gas emission

“…Fluidized bed incinerators are characterised by high flexibility, i. e. the possibility of burning fuels in all physical states [1][2][3][4][5][6][7], homogeneous thermal conditions and proper mixing of the fuel-oxidant system. They are used to burn fuels such as coal [8][9][10], biomass [11,12] and to dispose of solid waste.…”