Coal type

Properties. Pilot-unit data indicate the EDS process may accommodate a wide variety of coal types. Overall process yields from bituminous, subbituminous, and lignite coals, which include Hquids from both Hquefaction and Flexicoking, are shown in Figure 14. The Hquids produced have higher nitrogen contents than are found in similar petroleum fractions. Sulfur contents reflect the sulfur levels of the starting coals ca 4.0 wt % sulfur in the dry bituminous coal 0.5 wt % in the subbituminous and 1.2 wt % sulfur in the dry lignite. 

Pulverized-Goal Firing. This is the most common technology used for coal combustion in utiUty appHcations because of the flexibiUty to use a range of coal types in a range of furnace sizes. Nevertheless, the selection of cmshing, combustion, and gas-cleanup equipment remains coal dependent (54,100,101). 

Coal type Illinois 6 Illinois 6 Illinois 6 Illinois 6 Illinois 6 iUinois 5... 

Coal type Operating conditions Kentucky 9 14 Ilbnois No. 6 Illinois No. 6 Illinois No. 6 Ilbnois No. 6 Ibinois No. 6... 

Corex process. The Corex or Cipcor process has integral coal desulfurizing, is amenable to a variety of coal types, and generates electrical power in excess of that required by an iron and steel mill which can be sold to local power grids. A Corex plant is in operation in South Africa, and other plants are expected to be operational in South Korea and India. 

Coaling type Applicable standards Application procedures Typical system thickness (mm) Characteristics and uses... 

Some cokeless technologies in use or under development include the Japanese direct iron ore smelting (DIOS) process, in which molten iron is produced directly with coal and sinter feed ore, the HIsmelt process, where ore fines and coal are used to achieve a production rate of 8 t/h using ore directly in the smelter, and the Corex process, which has an integral coal desulfurizing step, making it amenable to a variety of coal types.14... 

But there are wide regional disparities with respect to distribution and coal type. 

Region In-place, billion tons Principal coal type... 

Figure 7. Relationship between coal type and extraction yield...

Storage in coal seams is a technically feasible option because C02 has a high affinity for adsorbtion to coal. Normally, coal is at least partly adsorbed with methane. Of these two molecules, C02 has a greater affinity to the coal. The ratio of affinity varies greatly, depending on the type of coal. It may range from close to one in anthracite to ten in younger coal types (Stanton et al., 2001). In consequence, if entered into a coal... 

Many factors affect the rate and extent of coal liquefaction, including temperature, hydrogen partial pressure, residence time, coal type and analysis, solvent properties, solvent-to-coal ratio, ash composition, and the presence or absence of a catalyst. Many kinetic expressions have appeared in the literature, but since they are generally specific to a particular process, they will not be listed here. In general, liquefaction is... 

Char oxidation dominates the time required for complete burnout of a coal particle. The heterogeneous reactions responsible for char oxidation are much slower than the devolatilization process and gas-phase reaction of the volatiles. Char burnout may require from 30 ms to over 1 s, depending on combustion conditions (oxygen level, temperature), and char particle size and reactivity. Char reactivity depends on parent coal type. The rate-limiting step in char burnout can be chemical reaction or gaseous diffusion. At low temperatures or for very large particles, chemical reaction is the rate-limiting step. At... 

In the context of the present discussion the term "mobile phase will be used to describe those components which can be thermally extracted ("distilled", "desorbed ) under vacuum at temperatures below the thermal degradation range of the coal. The residue, designated as the nonmobile ("network ) phase, is thermally degraded in the pyrolysis temperature range. Of course, the onset of pyrolysis may vary considerably, depending on heating rate, rank and coal type (10). 

Although the molecular conformation of organic solids profoundly affects their properties, In the case of coals this characteristic has been little studied compared to their chemical composition and functionality Studies of coal at any level of structure are difficult because of the complex heterogeneity of any particular coal and the great variability of coal types that occur ... 

The major limitation to the usefulness of each of these concepts (and, no doubt, the necessity for all three) stems from the great variability of coal types Also, these concepts have mostly been applied only to the vltrlnlte macerals ... 

Coal is a rich source of carbon and has been a valuable source of fuel for centuries. It is classified by both coal type and coal rank. Coal type is determined by the nature of the original biomass that led to the formation of the coal. Coal rank signifies the degree of maturation or chemical change in coal and usually determines coal quality. The calorific value, moisture content, elemental analysis, volatile matter, ash, and fixed carbon content are important qualities of coal. 

It is felt that any anthracite seam will readily yield such lithotypes. Because fusain is relatively soft and friable and is likely to be ground to fines during handling, it may appear only as coatings or fine bands in other coal types. The durain in many cases looks like slate. Not realizing these two factors one could, without close inspection, be easily misled into believing that the major lithotype, vitrain, is the only lithotype present in a particular seam. 

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