Coal treated

The first step — hydrogenation of coal — was the same for fuels and rubber. Powdered coal suspended in oil was pumped under great pressure with hydrogen over a catalyst and was converted into a synthetic crude oil. From this crude oil came Leuna gasoline, diesel fuel, iso-octane for aviation gasoline, ethylene oxide, and many other synthetic products. Coal, treated with scalding steam, was also processed into methanol. 

Various bituminous coals were demineralized by an experimental two-step leaching process in which the ball-milled coals were first treated with a hot alkaline solution and then with a dilute mineral acid. Different alkalis and acids were studied to determine their relative effectiveness. In addition, the effects of alkali concentration, treatment temperature, and treatment time were evaluated. Under the best conditions, the process reduced the ash content of the coals by 85-90% and the total sulfur content by 70-90%. As the temperature of the alkaline treatment was raised from 150 to 345 C, the removal of sulfur increased greatly whereas the recovery of organic matter declined. When a 1 M sodium carbonate solution was employed for the treatment, the recovery of organic matter was 91-97% for various coals treated at 250 C and 79-89% for the same coals treated at 300 C. 

Coal treated at the Ames Laboratory with molten caustic by a procedure similar to that of the Gravimelt Process resulted generally in 80-90% reductions in ash and 70-80% reductions in total sulfur. The recoveries of coal on a moisture- and ash-free basis were 80-90%. 

XRF data on coals treated with molten caustic at fitnes Laboratory showed that levels of Fe, which is predominantly associated with pyrite in coal, were reduced by about 90% for each of the two runs. Reductions in concentrations of other elements which form abundant minerals in coal, including Al, K, and Si, were also substantial. Because roughly 90% of the ash was removed, substantial concentration reductions in the major mineral-forming elements are expected. 

Levels of Ba, Rb, Sr, and Zn were reduced by 70% or more, and Se was reduced by 30% or more in the coal treated in the normal fashion (Run 1). In the coal from the test containing the iron additive (Run 2), levels of Rb, Sr, and Zn were also reduced by 70% or more. Pb levels remained essentially constant for each of the treated coals. The elevated Cr and Ni levels are believed to be corrosion byproducts from the reactor. 

In the coal treated by molten caustic in Run 2, the Cr and Ni levels are significantly higher than in Run 1, suggesting a more severe attack in the second test. If the attack were more severe, then levels of Fe, Al, Si, and ash would be anticipated to be somewhat lower than in Run 1. As can be seen from these data, this is indeed the case. However, because of the numerous variables involved, no definitive conclusions can be drawn. Overall trace element reductions did not seem to be significantly improved in Run 2. 

Results of chemical analyses on coals treated by the Gravimelt Process at TRW are shown in Table IV. Ash contents were decreased to 1% or less, and levels of As, Be, Cd, Hg, Pb, Se, Sr, and Zn were reduced by 75-95%. It is interesting to note that most of these elements are commonly associated with pyrlte. Thus, substantial reductions in levels of these elements can be anticipated when most of the pyrlte is removed (as indicated for both coal samples). In addition, the levels of Ba, Ge, Mn, and Rb were also reduced however, the reduction levels for these elements are not as prominent nor as clear-cut. 

The distributions of sulfur functional groups (DSFG) in four types of solids are described. The four types of solids are sulfur-containing polymers with distinct sulfur functional groups raw coals treated coals and iron pyrite. 

Figure 2. Pittsburgh coal treated unth HCl. Continuous line is the least-...

In general, too kilos of average coal on destructive distillation yield 0.25-0.3 kg. of ammonia or 1.0-1.2 kg. of ammonium sulphate. When, however, the coal undergoes destructive distillation in a stream af superheated steam (as in the processes of producing water gas or Mond gas from crude coal) we can obtain as much as 3 kilos of ammonium sulphate per 100 kilos of coal treated. 

Several bituminous coals have been employed during the course of this study. The method can be applied to relatively unprepared coals and seems to be very effective for the removal of alkali and alkaline earth metals which are related to boiler fouling. With modification, other mineral groups could be removed. Coal treated with CO2/H2O occasionally crumbles during processing. The system is flexible, may be modified both chemically and physically, and may be integrated into, or used to modify, an overall coal preparation... 

There are few direct measurements of the sulfur removed from coals treated in plasmas. Zavitsanos and Bleiler305 reported that coal could be desulfurized without loss of heating value by exposing coal particles of 0.1—4 cm size in 1.5-2 cm layers to 2.45 GHz microwaves for 40 s in air at 1—5 torr pressure. The coal temperature did not exceed 420 K and the sulfur content was reduced from 4.11 to 1.91%. However, Scott et al.224 did not observe any significant change in S content (2%) of bituminous coals as a result of exposure to 60 Hz discharges in the annular space of a Siemens tube. 

Certain forms of active carbon have been found to promote the dehydrogenation of paraffin hydrocarbons in preference to demethanation. Steam activated brown coals treated at 800° to 900° C. are particularly effective. By passing oxygen into the reaction zone together with the hydrocarbon to be dehydrogenated the hydrogen formed may be removed as water.149 Substantiation of the claims for this process are lacking, however. 

Coal. Pittsburgh seam coal was selected for the tests because of its commercial importance, its reputation as a typically strong caking coal, and easy access at our experimental mine at Bruceton, Pa. The maximum size of the coal treated (3/8 in.) was limited by the inside diameter of the treater (1.939 in.). During treatment the coal tends to become sticky while swelling to about 1-1/2 times its original size. 

Effect of Pressure. The effect of pressure on the methane yield and caking property of coal treated at high temperature was studied at 2.5, 5, and 8 atm. (Table IV). With an increase in pressure, however, the gas flow of steam plus oxygen must be increased to maintain the same linear... 

Table 5.21i Average amounts of exhalates formed in coke production (per 1 t of coal treated)... 

Table 10-15. Typical Composition of Coals Treated in Microwave Discharge System...

Generally, coal treated with bacteria shows an improvement in quality. Apart from the reduction of the sulfur content, the mineral matter content (measured as ash production) in bacteria-treated coals are substantially reduced. However, the removal of organic sulfur depends on the structure and type of the sulfur-containing organic compounds present in coal. 

The fact that additives may catalyze or otherwise affect combustion processes has been reported many times. For example, salt has long been known to be of some assistance in removing soot deposits from chimneys and coal treated with a more complex mixture of metal oxides (Table 14.3) has been reported to be activated in combustion systems but it is apparently not resolved whether... 

Warzinski, R.P., J.A. Ruether, S, Friedman, and F.W. Steff-gen. "Survey of Coals Treated by Oxydesulfurization." Proc. Symp. on Coal Cleaning to Achieve Energy and Environmental Goals." Vol. 

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