Particulate Matter Formation and Alkali and Alkaline Earth Metal Partitioning in a Pressurized Oxy-fuel Fluidized-Bed Combustor

Abstract

Pressurized oxy-fuel combustion is one of the advanced clean coal technologies. In comparison to conventional air combustion in atmospheric pressure, it can not only improve the overall plant efficiency but also reduce the cost of CO 2 capture. However, there are no available studies on the particulate matter (PM) formation during pressurized oxy-coal combustion. In this work, a 10 kW th pressurized oxy-fuel fluidized-bed combustor was used to explore the partitioning of alkali and alkaline earth metals (AAEMs) and their occurrence characteristics in PM under pressurized oxy-fuel combustion. Two different kinds of coals were tested in various system pressures (0.1, 0.3, and 0.5 MPa). In addition to air combustion, oxycombustion was also considered for limited cases. An electrical low-pressure impactor was used to measure real-time PM concentrations and collect size-segregated PM samples. Characteristics, such as morphology and elemental distributions, were studied for the generated PM. The experimental results showed that increased pressure can reduce the carbon content in ultrafine particles; thus, the concentration of ultrafine particles decreases along with the rising pressure. The rising pressure tends to promote the vaporization of AAEMs and further cause a higher concentration in sub-micrometer particles (PM 1 ), while the effect of the pressure on the distribution of AAEMs in super-micrometer particles (PM 1−10 ) is relatively negligible. Oxycombustion seems not to significantly affect the concentration of PM or the distribution of AAEMs when the oxygen concentration is lower than 30%.

Mechanism of CO2 and H2O Action on Char in Oxy-fuel Combustion with Wet Flue Gas Recirculation

“…The reactive groups on the surface of the char was detected by Fourier transform infrared spectroscopy (FTIR). , The combustion reactivity of char was examined using the microfluidized bed reaction analyzer (MFBRA) system (detection temperature, 1073 K; detection atmosphere, air) …”

“…About 25% of CO 2 emissions from human activities are generated by fossil fuel combustion. , Oxy-fuel combustion uses fossil fuels, such as coal, to produce high concentrations of CO 2 by burning them in a mixture of pure oxygen and recirculated flue gas. The high concentrations of CO 2 obtained are then further compressed and sequestered .…”

Life-Cycle Environmental and Economic Assessments of the Oxy-coal Combustion System Combined with a Pressurized Circulating Fluidized Bed and the Supercritical CO2 Brayton Cycle

“…The PM2.5 and PM10 are assumed to be 0.45 A and 1.54 A , respectively, where A is the percentage of ash in the coal. It seems that oxy-coal combustion will not significantly affect the concentration of PM when the oxygen concentration is less than 30% . The electricity demand for ESP operation is 1.18 kW/MW …”

“…It seems that oxy-coal combustion will not significantly affect the concentration of PM when the oxygen concentration is less than 30%. 60 The electricity demand for ESP operation is 1.18 kW/MW. 61 Due to the lack of mercury and chlorine content data, the average values of coal in Jiangsu, China, used were 0.22 mg/kg and 262 mg/kg, respectively.…”

Virtual Special Issue of 7th Sino-Australian Symposium on Advanced Coal and Biomass Utilisation Technologies

“…Huang et al (10.1021/acs.energyfuels.9b03271) 41 investigate the ultrafine PM formation from the combustion of coal, biomass, and waste, with a special emphasis on the relationship with flame synthesis. Duan et al (10.1021/acs.energyfuels.9b02913) 42 report the formation of PM and the partition of alkali and alkaline earth metals in a pressurized oxy-fuel fluidized-bed reactor. Zhu et al (10.1021/acs.energyfuels.9b02967) 43 investigate the influence of a P-containing additive on the emissions of fine PM during cornstalk combustion.…”