Oxy-fuel combustion technology for coal-fired power generation

Particulate matter (PM) emissions from stationary combustion sources burning coal, fuel oil, biomass, and waste, and PM from internal combustion (IC) engines burning gasoline and diesel, are a significant source of primary particles smaller than 2.5 μm (PM2.5) in urban areas. Combustion-generated particles are generally smaller than geologically produced dust and have unique chemical composition and morphology. The fundamental processes affecting formation of combustion PM and the emission characteristics of important applications are reviewed. Particles containing transition metals, ultrafine particles, and soot are emphasized because these types of particles have been studied extensively, and their emissions are controlled by the fuel composition and the oxidant-tem-perature-mixing history from the flame to the stack. There is a need for better integration of the combustion, air pollution control, atmospheric chemistry, and inhalation health research communities. Epidemiology has demonstrated t...

https://www.tandfonline.com/doi/pdf/10.1080/10473289.2000.10464197

Combustion aerosols: factors governing their size and composition and implications to human health.

Toxic metal emissions from incineration: Mechanisms and control

Grate-firing of biomass for heat and power production

Status of trace element emission in a coal combustion process: a review

The composition and size distribution of fly ash produced by burning a Montana lignite at two temperatures, 2050 and 2450, were determined. The ash showed a bimodal size distribution with a submicron fraction that was significantly enriched in the volatile trace species. The amount of submicron aerosol increased markedly with combustion temperature, from 4% of the ASTM ash value of the coal at 2050 K to 20% at 2450 K, supporting the hypothesis that the enrichment in more volatile species of the smaller ash particles is due to a process of vaporisation and recondensation of mineral constituents.

Mineral matter and trace-element vaporization in a laboratory-pulverized coal combustion system

The factors governing the amount and properties of the submicron aerosol (fume) produced on combustion of coal have been studied by burning size-graded Montana lignite particles in a laminar drop-tube furnace at 1750 K. The coal particle temperatures achieved vary from 1800 K to 2800 K as the oxygen concentration in which the particles burn is increased from 5% to 100%. Size fractionation of the ash yields a bimodal size distribution. The average size of the fine particles varies from less than 50diameter to greater than 300 , depending on the combustion conditions. These fine particles are produced by vaporization of the mineral matter species during combustion and their subsequent recondensation. The amount of fume produced as metal oxides increases from 0.1% of the total ash at particle temperatures around 1800 K to 20% at 2800 K. The chemical composition of the Montana lignite fume is dominated by the refractory oxides MgO and CaO at all but the lowest temperatures (T The oxidation of the vaporized reduced-state species away from the particle surface results in a supersaturation of the refractory oxides, leading to their nucleation. A simple model in which growth of these particles then occurs by coalescent collisions and by heterogeneous condensation of new material released from the burning particles provides a good representation of the observed particle sizes as a function of residence time and degree of ash vaporization.

Vaporization and condensation of mineral matter during pulverized coal combustion

Factors governing the surface enrichment of fly ash in volatile trace species

Eleven selected coals were burned under controlled conditions in a laboratory combustion furnace to determine the effect of coal type on the amount and composition of combustion generated inorganic submicron particles. Significant differences in both the amount and composition of submicron particles were found between coals and particularly between rank of coals. In most cases, however, the extent to which an element appeared in the submicron fume could be correlated on the basis of its occurrence and distribution in the coals.

Richard J. Quann

Papers

Mineral matter and trace-element vaporization in a laboratory-pulverized coal combustion system

Vaporization and condensation of mineral matter during pulverized coal combustion

Factors governing the surface enrichment of fly ash in volatile trace species

A Laboratory Study of the Effect of Coal Selection on the Amount and Composition of Combustion Generated Submicron Particles

A scanning electron microscopy study of the transformations of organically bound metals during lignite combustion