• Journal of Energy Engineering
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• v.23 no.4
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• pp.207-214
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• 2014

With the depletion of high grade coal, it is indispensable to be used co-combustion of low rank coal with bituminous coal in pulverized coal-fired power plants. This study describes the detailed measurements of combustion characteristics of bituminous and subbituminous coal in a 0.7MWth pilot-scale test facility. This experimental works include the measurement of gas temperature, gas concentrations along with the reactor axial and radial distance at the condition of excess air ratio of 1.2. The solid sampling was carried out and analyzed with the combustion of bituminous coal. The main reaction zone of coal flame in a reactor was formed about 1 m from the swirl burner, and at downstream, the fully developed temperature and species distribution was observed. The sampled particles of bituminous coal in a reactor revealed the complete carbon burn-out was achieved just after an main combustion zone.

• Korean Chemical Engineering Research
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• v.48 no.2
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• pp.268-274
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• 2010

Emission of heavy metals as hazardous air pollutants has been focused with tightening regulatory limits due to their hazardousness. Measurements and characteristic investigations of heavy metals emitted from a commercial power plant burning anthracite coal have been carried out. The plant consists of a circulating fluidized bed combustor, a cyclone, a boiler and an electrostatic precipitator(ESP) in series. Dust and gaseous samples were collected to measure main heavy metals including gaseous mercury before ESP and at stack. Dust emissions as total particulate matter (TPM), PM-10 and PM-2.5 at inlet of ESP were very high with 23,274, 9,555 and $7,790mg/Sm^3$, respectively, as expected, which is much higher than those from pulverized coal power plants. However TPM at stack was less than $0.16mg/Sm^3$, due to high dust removal efficiency by ESP. Similarly heavy metals emission showed high collection efficiency across ESP. From particle size distribution and metal enrichment in sizes, several metal concentrations could be correlated with particle size showing more enrichment in smaller particles. Mercury unlike other solid metals behaved differently by emitting as gaseous state due to high volatility. Removal of mercury was quite less than other metals due to it's volatility, which was 68% only. Across ESP, speciation change of mercury from elemental to oxidized was clearly shown so that elemental mercury was half of total mercury at stack unlike other coal power plants which equipped wet a scrubber.

• Resources Recycling
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• v.32 no.1
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• pp.50-59
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• 2023

The amount of dust generated during the dissolution of scrap in an electric arc furnace is approximately 1.5% of the scrap metal input, and it is primarily collected in a bag filter. Electric arc furnace dust primarily consists of zinc and ion. The processing of zinc starts with its conversion into pellet form by the addition of a carbon-based reducing agent(coke, anthracite) and limestone (C/S control). These pellets then undergo reduction, volatilization, and re-oxidation in rotary kiln or RHF reactor to recover crude zinc oxide (60%w/w). Next, iron is discharged from the electric arc furnace dust as a solid called Fe clinker (secondary by-product of the Fe-base). Several methods are then used to treat the Fe clinker, which vary depending on the country, including landfilling and recycling (e.g., subbase course material, aggregate for concrete, Fe-source for cement manufacturing). However, landfilling has several drawbacks, including environmental pollution due to leaching, high landfill costs, and wastage of iron resources. To improve Fe recovery in the clinker, we pulverized it into optimal -sized particles and employed specific gravity and magnetic force selection methods to isolate this metal. A carbon-based reducing agent and a binding material were added to the separated coarse powder (>10㎛) to prepare briquette clinker. A small amount (1-3%w/w) of the briquette clinker was charged with the scrap in an electric arc furnace to evaluate its feasibility as an additives (carbonaceous material, heat-generating material, and Fe source).