Blended coal sample

If decrepitation or entrainment takes place, the coal sample may be either heated more slowly or blended with a coking coal (the total volatile matter of which is known) in the ratio 4 1 and the test carried out with the blend. 

This experiment adopts Xinjiang Wuhu coal sample. Select 13 mm, 3-7 mm, 7-10 mm, and the first to four size mixing coal blend for experiments after affirming device normal. Select 200 g coal samples. The heating rate is l°C/min. The inlet flow rate is 90 ml/min. Take a set of gas sample every 20°C in 30-300°C. After 300°C every 30 C take a set of gas sample. These gas samples are detected by gas chromatograph. 

Some of the most common methods to evaluate the suitability of a coal or coal blend for coke production are the free-swelling index test, Gray-King assay, Roga assay, various dilatometer tests, and Gieseler plastometer test. In addition, research using larger amount of coal sample is also performed by means of a pilot coke oven. 

The clear knowledge about the purity of a coal is decisive for the correct design of gasification processes. No other method than the petrographic analysis, especially the reflectance analysis, gives a more precise statement regarding composition of a coal sample. Other bulk parameters, such as fraction of volatile matter, carbon content, or heating values, are inappropriate to determine whether a pure coal or a mixture (coal blend) are on hand. 

Coal Tar Assessment To assess the potential influence of coal tar particles on the field study s analytical results, a simple test was begun in 2006. In that test, crushed (-1 mm) coal tar retrieved from the Erie Pier site was blended with a PAH-free inorganic silt substrate (Fig. 32.23) at a ratio of 10 g of coal tar per 10,000 g of silt and was placed in two plastic bins. Assuming the coal tar sample was pure product, that is, 100% PAH, and that 100% extraction and recovery were achiev-... 

Coke sampling is marginally less problematic because the product from a single source derives from coal or blend of coals that have been prepared to a specification for ash, moisture, particle size distribution, etc. The final coke produced will be relatively homogeneous in all properties, with the exception of size distribution. Standard methods are available for coke sampling that reflects the somewhat less rigorous requirements for this material. 

The pilot ICDACs were obtained by blending the activated carbon samples produced during two of the pilot production tests and ground to two particle size ranges (5 and 8pm). The finer particle size sample, AC-F, had a slightly greater ash content (24.7 wt.%) than did the coarser AC-C sample (18.8 wt.%). The surface areas of the pilot carbons (671 and 688 m /g) were comparable to the activated carbon produced from C2 coal in the bench FBR (FBR-39 series). 

Gypsum samples were also taken from two Spanish pulverized coal (co) combustion power plants and the mercury species identified were different (Figure 4) [92]. The study was carried out in two (A and B) power plants equipped with high efficiency ESPs and a wet limestone-based with forced oxidation FGD facility. Power plant A bums a coal blend ranging from local sub-bituminous coals (60%) close to lignite to bituminous coals (40%), while power station B burns a blend of antliracites (80%) and petroleum-coke (20%). Gypsum samples were called FGD-A and FGD-B from power station A and B, respectively. 

The only differences noted in the chemical analyses of the bottom ash and fly ash samples were an increase in zinc noted in the fly ash and an increase in metal from the tire chips noticed in the bottom ash when firing the TDF blends compared to coal alone. Following these tests, magnetic separation equipment was installed at the ash pond to remove the ferrous metal from the bottom ash. This render the bottom ash acceptable for use by the local municipalities as a traction agent in the wintertime. A scrap metal dealer recycle the metal. 

Especially the comparison of the anthracite (Figure 3.2b) and the three-coal blend with overlapping peaks (Figure 3.2d) should call attention to always interpret the standard deviations and appearance of the maxima with reference to the rank of the sample. In general, it can be stated that for coal with mean reflectance Rr < 2.0%, a standard deviation s < 0.1 indicates a pure coal. 

As shown in the previous section, a petrographic analysis should not be limited to fresh coal only for rank and blend determination. Also specific samples from unstable gasifier operation, depositions, and solid by-products can reveal significant information understanding the process and resolving potential problems. 

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