Release of K and Cl and Emissions of NO_x and SO₂ during Reed Black Liquor Combustion in a Fluidized Bed

Abstract

For predicting and relieving ash-related problems and harmful gas emissions during fluidized bed combustion, release of K and Cl and emissions of NO x and SO 2 during reed black liquor (BL) combustion in a fluidized bed were investigated in this study. The effects of bed material (calcium-based zeolite and limestone) and bed temperatures (700−900 °C) were also studied. The results showed that higher temperature favored the K release for both calcium-based zeolite and limestone, and calcium-based zeolite caused lower K release due to the formation of K 3 Al(SO 4 ) 3 , KAl(SO 4 ) 2 , and K 2 O-Al 2 O 3 -SiO 2 eutectic compounds. Cl was mainly released in the form of HCl above 700 °C. Moreover, high temperature facilitated Cl release for calcium-based zeolite, whereas it had a complicated effect on Cl release for limestone. Although higher temperature increased the NO x emission for both calcium-based zeolite and limestone, limestone resulted in higher NO x emission due to the conversion of fuel N to NO x under CaO catalysis. Temperature had a slight effect on SO 2 emission for calcium-based zeolite, whereas it decreased the SO 2 emission for limestone. Reed BL combustion generated lower SO 2 emissions with the help of Na 2 CO 3 and K 2 CO 3 , and limestone resulted in much lower SO 2 emission with the help of CaCO 3 and CaO.

Combustion Performance and Ash Compositions during Biomass/Semi-Coke Blended Fuel Oxy-Fuel Circulating Fluidized Bed Combustion

“…Only little Cl was detected in bottom ash and circulating ash, only about 10% of the theoretical value, indicating that Cl can achieve almost complete release during the combustion process, which was in accordance with a previous study. 34 Notably, the Cl content was greatly enriched in the deposit, achieving over 2.5% under a 25% blending ratio. Enrichment of Cl in fly ash can also been observed, of which the degree was lower than that in the deposit.…”

Direct Pyrolysis of Reed Black Liquor Droplets in a Fluidized Bed

“…Yang et al , studied the RBL’s CO 2 gasification characteristics. Research studies have also been carried out on the production of activated carbon from RBL. , Ji et al − tested in a fluidized bed according to a few different ways.…”