Hydrogenation system, coal

Solvent-Refined Coal Process. In the 1920s the anthracene oil fraction recovered from pyrolysis, or coking, of coal was utilized to extract 35—40% of bituminous coals at low pressures for the purpose of manufacturing low cost newspaper inks (113). Tetralin was found to have higher solvent power for coals, and the I. G. Farben Pott-Broche process (114) was developed, wherein a mixture of cresol and tetralin was used to dissolve ca 75% of brown coals at 13.8 MPa (2000 psi) and 427°C. The extract was filtered, and the filtrate vacuum distilled. The overhead was distilled a second time at atmospheric pressure to separate solvent, which was recycled to extraction, and a heavier liquid, which was sent to hydrogenation. The bottoms product from vacuum distillation, or solvent-extracted coal, was carbonized to produce electrode carbon. Filter cake from the filters was coked in rotary kilns for tar and oil recovery. A variety of liquid products were obtained from the solvent extraction-hydrogenation system (113). A similar process was employed in Japan during Wodd War II to produce electrode coke, asphalt (qv), and carbonized fuel briquettes (115). 

Pollutant Fossil fuel system (kg/GJ) Coal/synthetic fossil system (kg/GJ) Solar-hydrogen system (kg/GJ)... 

Item Unit Fossil fuel system Coal/synthetic fossil system Solar- hydrogen system... 

Since this evaluation is only demonstration of the method and procedure, it would be inappropriate to make any finale conclusion of the potential selection of the hydrogen system as it was demonstrated in this evolution. But, still it can be concluded that under circumstances demonstrated in this evaluation coal and natural gas with fuel cell systems are presently the most attractive potential systems to be selected among the options under consideration. Also, natural gas and nuclear systems with fuel cell and gas turbine options are potentially acceptable solution for the situation where it can be in accordance with respective local condition. It should be emphasized that the utilization options are not substantially affecting priority of the options under consideration. 

David Gray and Glen Tomlinson, Mitretek Systems, Hydrogen from Coal, presentation to the committee, April 24, 2003. 

More recently, Yavorsky, et al., (5) have reported on the development of a liquid phase (solvent) hydrogenation of coal In a highly turbulent tubular reactor In the presence of a packed solid catalyst. Residence times In the order of several minutes were reported and an oil product Is formed. This system Is a considerable Improvement over the Berglus Process since reduced pressure. 

Coal system (Fig. 2) can join with a solar hydrogen system which is very difficult in the global transportation, at the processes of CO2 recovery and fuel synthesis (Fig. 3). 

Low sulfur fuel oils were prepared from a high volatile bituminous coal by hydrogenation under high temperatures and pressures. At a coal conversion of 80%, the ratio of oiU to-gas yields was about three, and 23% of the coal sulfur was contained in the oil. Sulfur content of the oil, however, remained the same at different coal conversion levels. The data obtained in the semi-continuous, dilute phase hydrogenation system showed that the whole oil can be directly used as a fuel oil where 1% sulfur is tolerated. Fuel oils containing 0,5 and 0,25% sulfur were produced by desulfurization of the whole oil, A preliminary economic evaluation indicated that low sulfur fuel oils can be produced from coal by hydrogenation at a manufacturing cost of about 5-6 per barrel. 

Figure 2. Coal hydrogenation system (bench scale)...

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