Particulate matter formation mechanism in pressurized fluidized bed combustion of various solid fuels

Abstract

Pressurized fluidized bed combustion (PFBC) is an advanced clean coal technology, and co-combustion of coal and biomass can effectively reduce pollutant and greenhouse gas emission during power generation. However, studies concerning the particulate matter formation during coal and biomass co-firing in PFBC are very rare. In this work, experiments on combustion of different solid fuels (two lignites, one bituminous coal, rice husk) and co-combustion of coal and biomass were carried out at 10 kW pressurized fluidized bed with system pressure of 0.5 MPa. Despite the different fuel types, pressurized combustion produces PM1 with higher content of easily vaporized elements (Na, K, and S), while super-micron particles are mainly composed of refractory elements (Ca and Si). For the cases of cofiring coal with biomass, it was found that the mineral interaction can reduce the yield of submicron particles, such as PM0.4 formation in Zhundong lignite/rice husks and Xiaolongtan lignite/rice husks were reduced by 28% and 47%, while the reduction is 61% and 64% for PM1, and 80% and 75% for PM2.5. Overall, this work provides the insight on particulate matter formation during the combustion of various solid fuels in pressurized combustion conditions, which hopefully can help the development of PFBC technology.