Characteristics of distinct ash flows in a biomass thermal power plant with bubbling fluidised bed combustor

Evaluating Biomass Ash Properties as Influenced by Feedstock and Thermal Conversion Technology towards Cement Clinker Production with a Lower Carbon Footprint

“…This trend can be associated to the inclusion of Si-rich exogenous material such as sand, dust and concrete debris which is collected together with the treated wood and the presence of bark tissue in the untreated wood. The inclusion of exogenous material is common for the treated wood subgroup and contributes significantly to Si, Al and Fe concentrations resulting in a lower CaO/SiO 2 ratio and higher Al 2 O 3 + Fe 2 O 3 concentration [38] Fig. 2).…”

“…In fact coarse exogenous material can still be sufficiently small to be entrained with the flue gas and to reach the fine ash fraction, influencing its composition. Tarelho et al [38] measured the average particle size of exogeneous material and found that 67% by mass is below 500 µm concluding that part of these particles can be entrained with combustion flue gases and, successivly, be collected in the cleaning gas section. These results indicate that careful handling and processing of biomass by avoiding the inclusion of soil, dust and other inert materials can reduce the amount of silicon ending up in the fine ash fraction, thus improving the quality of the ash in terms of its CaO/SiO 2 ratio.…”

Big problem, little answer: overcoming bed agglomeration and reactor slagging during the gasification of barley straw under continuous operation

“…13,17,21,22,28,29 The most problematic elements that participate in bed agglomeration are K, S, Cl and P, this is because they can form low melting point compounds with the bed material. 27,[30][31][32][33][34][35] From the list of elements mentioned, the most troublesome is K, this is due to its reactivity and ability to form low temperature eutectic mixtures with Si, a common/cheap major component in bed materials which have much lower melting point than SiO 2 (1710 C). The combination of these two elements in various stoichiometries can produce a material which has a melting point as low as 764 C. 14,22,27,30,[35][36][37] The presence of Cl enhances the mobility of K by forming KCl slag deposits on cold spots on the reactor walls.…”

“…However, solid fuels with a high concentration of Ca will decrease this tendency with Si. 20,21,25,27,32 For formed alkali silicate mixtures, residual S can facilitate a further decrease in melting temperature to around 700 C. This means that such bed agglomeration is possible for combustion, low temperature gasication and pyrolysis conditions. 11,15,25,38 The stoichiometry of eutectic mixtures can be varied by the inherent Si content in the waste feedstock.…”

Experimental and numerical analysis of cylindrical straw drying

“…The easiest way is to use shredded straw in large power boilers, where the fuel moisture is not so relevant [2,3,4]. In addition, in the case of shredded straw, drying of the fuel is relatively simple, because the solutions for drying loose materials have been known for many years and they are still used, for example: rotary dryers [5,6,7], pneumatic dryers [8,9], fluidized bed dryers [10,11,12], belt dryers [12,13,14].…”