Multi-stage model for the release of potassium in single particle biomass combustion

Abstract

The release of potassium during biomass combustion leads to several problems as the emissions of particle matter or formation of deposits. K release is mainly described in literature in a qualitative way and this work aims to develop a simplified model to quantitatively describe it at different stages. The proposed model has 4 reactions and 5 solid species, describing K release in 3 steps; during pyrolysis, KCl evaporation and carbonate dissociation. This release model is coupled into a single particle model and successfully validated with experiments conducted in a single particle reactor with spruce, straw and Miscanthus pellets at different temperatures. The model employs same kinetic parameters for the reactions in all cases, while different product compositions of the reactions are employed for each fuel, which is attributed to differences in composition. The proposed model correctly predicts the online release at different stages during conversion as well as the final release for each case.

The Influence of Addition of Expired Pharmaceuticals on Thermal Behaviour of Selected Types of Biomass

“…Moreover, the char material of the CC sample with additives has an almost 2.5-3-fold content of K atoms. This gives a reason to presume that the used additives initiate the processes of migration of K atoms [32,33] in biomass samples during pyrolysis. It cannot be excluded that besides the K atoms, other atoms may undergo migration with volatiles.…”

Influence of Operating Parameters on Chlorine Release and Pollutant Emission Characteristics of a 130 t/h BCFB Combustion System

“…Currently, a large number of studies − have shown that chlorine enters the gas phase mainly in the form of HCl and KCl during the combustion of biomass. At 700–900 °C, chlorine basically enters 100% into the gas phase, while potassium partially enters the gas phase. − All of the potassium volatilized from the biomass existed in the form of KCl in the gas phase, while the remaining chlorine entered the gas phase in the form of HCl within the operating temperature range of the BCFB. The proportion of solid potassium transformed into gaseous potassium in the biomass fuel used in the CBFB was 5% (700 °C), 10% (800 °C), and 30% (900 °C), respectively.…”

Visualization of Combustion Phases of Biomass Particles: Effects of Fuel Properties

“…Globally, as a renewable energy resource, biomass is seen as a CO 2 neutral fuel due to the carbon cycle and because bioenergy is renewable in nature. , However, biomass energy use accounts for only 14% of the total energy consumption. , Biomass combustion is a convenient way for CO 2 reduction, due to its CO 2 -neutral characteristics, and the relative ease of utilizing as a fuel in the existing pulverized fossil fuel-fired thermal power plants. , …”

“…1,2 However, biomass energy use accounts for only 14% of the total energy consumption. 3,4 Biomass combustion is a convenient way for CO 2 reduction, 5 due to its CO 2 -neutral characteristics, and the relative ease of utilizing as a fuel in the existing pulverized fossil fuel-fired thermal power plants. 6,7 Solid biofuels have lower ignition temperatures, lower energy content, and shorter burnout times 8 compared to coal.…”