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%.

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The environmental protection has become one of the factors that affect and restrict the development of human society. With the continuous development of industry and the rapid increase of urban population, a large number of industrial and domestic sewage discharges into rivers and lakes without treatment, so that the environment and the application of water are seriously polluted. In this paper, the principle and characteristics of PLC(PLC is the abbreviation of Programmable Logic Controller) are introduced; the process of PLC sewage treatment is expounded, and the application of PLC in sewage treatment is described.

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