Coal tested

S.E. Carr and C.R. Moser, Proceedings Inti Coal Testing Conference, Lexington, KY (1990), pp. 52-6. 

Figure 2. Distribution of liquefaction conversion for coals tested in Gulf con-tinuous-flow unit (455° C)...

The cushioning effects of fines of South Blackwater and Ensham coal tested on steel surface at 5 m drop height were shown in Figs. 2 and 3. Data for the Fig. 2 are given in Table 2. The result of these figures shows that, there was a significant difference of fines percentage between the non-cushioned and cushioned coal sample. Non-cushioned coal sample of South Blackwater coal dropped on steel surface produced 12% more fines than a cushioned coal sample, 13.3% more fines than a sample of initial 10% fines, 27.5% more fines than a sample of initial 30% fines and 30.9% more fines than a sample of initial 50% fines at 30 m total drops (six drops at 5 m) shown in Fig. 2. 

Fig. 8. Comparison of percentage of fines generation of three impact surfaces of South Blackwater coal tested with cushioned coal sample.

Comparison of two types of coal tested on three surfaces... 

When two types of coal are compared, the coal sample of initial 10% fines of south Blackwater coal dropped on steel surface produced 5% more fines than Ensham coal at 30 m total drops shown in Fig. 14 and there was no significant difference of fines percentage between two types of coal tested with initial 30% fines sample on steel surface shown in Fig. 14. 

The addition of T. ferrooxidans in salt medium at the desired concentration to the coal/water slurry increased the corrosion rates for both the coals tested. The corrosion rates for the 72-hour and 500-hour experiments in the presence of T. ferrooxidans in salt medium with 10 wt% slurry of Illinois //6 ranged from 4.2 X 10 3 ipy to 1.41 X 10 ipy, respectively. However,the introduction of up to 10 ppm of a commercial corrosion inhibitor, Calgon T G-10, inhibited the corrosion rates with Illinois 6 and Indiana 3 coals to very low levels approaching those obtained with the deionized water. Balck Mesa pipeline has used this corrosion inhibitor on a regular basis with very satisfactory results. 

Little systematic, quantitative information is available concerning the effects of coal type on hydrocarbonization yields. In general, however, hydrocarbonization yields may be estimated by normalization of known results by the Fisher assay of the coal tested and thereby extended to other coals. The pronounced effects of coal type on operability and product quality are reviewd below. 

Pilot Plant. At Texaco s Montebello Research Laboratory there are two pilot gasifiers, Figure 6, each capable of processing 15 to 20 tons per day of coal. Tests on a wide range of coals have been conducted at pressures ranging from 300 to 1200 psi. 

About half of the coals tested are suitable for a process which entails solubilization of coal as an initial step. These dissolve readily to yield solutions which can be filtered to remove ash (including inorganic sulfur compounds). Eighty to 90 percent of the maf coal goes into solution to become available for subsequent hydrogenation to oils. 

Clearly, the rate process is not first order and this is true of all the coals tested. Wiser (14) has compared the kinetics of coal pyrolysis and solvent extraction. In solvent extraction, the yield curves of fraction extracted versus time closely resemble the curves shown in Figure 1. Wiser showed such data exhibit compliance with second order kinetics in the early period of reaction and revert to compliance with first order kinetics in later stages. Hill, et (15) also showed that activated extraction of coal witF hydrogen donor solvents behaved in this manner. 

Thus, there appears to be something unique about the weakly acidic phenolic materials. In addition to phenol itself, 3,5-xylenol, 2-naphthol, phenol-naphthalene (1 1). and cresylic acid all show ability to solubilize the coal. Recently, Darlage and Bailey have studied the phenol catalyzed depolymerization of a Kentucky coal (Pond Creek Seam, Pike County). (16) This coal does not depolymerize efficiently and would compare with the poorest coals tested with data shown in Table II. These authors also show that phenolic solvents in general cause solvation of coal whereas non-phenolic aromatics add to coal but do not solubilize the coal. 

Coal Used. The coal tested was Morwell brown coal from Victoria, Australia. Its composition on a dry basis is shown in Table I. This coal contains over 60% moisture as mined. It was ground wet to 80% less than 25 mesh and used in the wet state (60% moisture). 

Analyses of the coals tested are given in Table II. Most of the tests were conducted with the 1.6-percent-sulfur Pittsburgh seam coal. Twelve tests were carried out with the 3.1-percent-sulfur West Virginia coal. [This also is a Pittsburgh seam coal, but is referred to as "West Virginia coal" (from Marion County, West Virginia) to facilitate discussion.] Two tests were conducted with the 1.0-percent-sulfur Kentucky coal. 

Pretreatment Temperature. Perhaps the most critical operating variable is temperature. The coals tested have a plastic point temperature around 700°F. Below this temperature, we could not produce a free-flowing coal with a 2-hr. residence time and a wide range of oxygen concentrations in the pretreatment gas. On the other hand, localized combustion begins at bed temperatures near 775°F. The heat released can not be dissipated by the bed, and runaway temperature results. 

Table I. Analyses of High Volatile Content Bituminous Coals Tested in Pretreater...

During the coal tests the rate of slag flow through the tap hole, calculated from the slag-tapping times, was between 10,000 and 14,000 lb./hr. whereas the rates were as high as 30,000 lb./hr. with coke. This was not caused by any difference in the rheological properties of the... 

The loss of ash constituents from the coals tested were significantly lower than for coke, except for chlorine and sulfur. Silica losses were negligible, apart from the test with untreated coal that contained a high proportion of shale. 

The coal tested was a high volatile B Utah coal from the Orangeville, Carbon County area. Typical proximate and ultimate analyses of coal from this area are listed in Table I. The coal was dried, ball-milled, and screened to —200 mesh for these tests. The moisture as used in the tests was less than 1%. 

Because of the broad similarity to coal, tests to assess the potential for fouling (and/or slagging) have been based on those developed for coal, for instance the temperature indicators described in Section 16.3.2.1 Dabron and Rampling [1988] have given some ash fusion data for refuse derived fuel from three different UK incinerators and compared them with a coal as presented in Table 16.16. 

Two exposures have been completed in both the CONOCO COAL gasifier and regenerator. Linearly extrapolated corrosion rates for selected alloys exposed in these CONOCO COAL test locations are presented in Figs. 

Figure 3. Electromagnetic waves schematics coal testing laboratory.

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