Layer formation on K-feldspar in fluidized bed combustion and gasification of bark and chicken manure

Abstract

Layer formation on K-feldspar in fluidized bed combustion and gasification of bark and chicken manure, Biomass and Bioenergy. 127 (2019) 105251.

Impact of residual fuel ash layers on the catalytic activation of K-feldspar regarding the water–gas shift reaction

“…Furthermore, the utilization of residual biomass of lower quality than stem-wood-based biomass is of high interest for improving the economic feasibility of the process as well as increasing the share of renewables in the energy mix. Previous studies have been focused on the use of, e.g., chicken manure, bark, straw, sugar cane bagasse, or exhausted olive pomace as residual biomass [21][22][23]. Different residual biomasses cannot be compared easily since their composition and fuel characteristics vary greatly.…”

“…While studies referring to industrial-scale plants mainly focused on olivine as a bed material [26], several alternative bed materials have been studied in lab-to pilot-scale experiments, where an activation could be observed [16,17,27,28]. Studies have shown that the layer formation during (steam) gasification is comparable to layer formation during combustion [29,30].…”

“…Selective tests of the catalytic activity showed no activity regarding the WGS reaction [25] and tar reduction [41], though it was possible to observe an activation over time during DFB steam gasification with an ash-rich fuel mixture of bark, straw, and chicken manure [24]. The influence of phosphorus, originating from chicken manure, on layer formation on K-feldspar was studied for combustion and steam gasification atmosphere by Wagner et al [27]. No differences in the layer formation mechanism could be observed between combustion and gasification; a difference could only be detected between phosphorus-lean and phosphorus-rich fuels.…”

Layer formation mechanism of K-feldspar in bubbling fluidized bed combustion of phosphorus-lean and phosphorus-rich residual biomass

“…Due to the observed problems of agglomeration and deposition formation with quartz beds [7,16,17], several alternative bed materials, like olivine [6], K-feldspar [6], magnesite [17][18][19], calcite [18,19], dolomite [17], sillimanite [18], bauxite [18], and plagioclase [6], were tested for their suitability in fluidized bed applications. Further studies on K-feldspar focused on the layer formation in combustion [14] and gasification atmosphere [12], or a direct comparison of both [20]. Berguerand and Berdugo Vilches tested Alkali-feldspar (a mixture of K-and Na-feldspar with impurities of Ca-feldspar) in the Chalmers 2 MW indirect gasifier as bed material for gasification applications with wood.…”

“…For a quartz bed, changes in ash chemistry based on phosphorus content could be observed in the gas phase [23] and through its influences on bed agglomeration tendencies [4]. Phosphorus-rich fuels were tested in a gasifier and in combustion atmosphere in combination with K-feldspar [20,22] also giving a first proposal regarding a possible layer forming mechanism on K-feldspar. Further, the importance of phosphorus as a nutrient is recognized among the planetary boundaries along with eight other criteria [24].…”