Reaction mechanism of coal liquefaction and coal reactivity of 10 different coals for liquefaction were examined with an excess amount of tetralin at 723K under 10MPa of nitrogen gas atmosphere. The amount of naphthalene formed from tetralin during coal liquefaction was measured by FID-GC for the determination of hydrogen consumptions of coals. Coal was considered consisting of three different reactive components, I0, C1 and C2 defined from their hydrogenation characteristics. The component I0 was inherently inert in the present reaction condition. The component C1 formed consecutively oils and gases via preashaltenes and asphaltenes with consuming hydrogen. On the other hand, the component C2 formed oils and gases directly without consuming external hydrogen from the solvent and the gas phase. Hydrogen consumptions for various coals were predicted by the initial content of C1 in original coals within negligible small error. The amount of hydrogen consumed for formation of preaphaltenes and asphaltenes was not as predominant as that for oil formation involving gases formed. These results, furthermore, showed that reaction selectivities between intermolecular hydrogen of tetralin and gaseous hydrogen were different even in the same reaction condition, i.e. temperature and pressure. It was suggested that the difference among chemical structures of solvent having transferable hydrogen affected an efficient hydrogen utilization in coal liquefaction and that the role of hydrogen donor solvent might be enhanced by hydrogenation of aromatic ring during heating in the presence of catalyst.
Characterization on two sorts of coal gasification slag, Blair Athol and Taiheiyo, with limestone additive was performed in order to obtain the relation between character of glass phase and pozzolanic reactivity of blending component. The content of CaO in slag was varied from 0 to 40wt%. The pozzolanic reactivity of the slag is enhanced with increasing of basicity, content of acid soluble SiO2, Al2O3, and CaO content in slag, and decreasing of degree of condensation of silicate ion in the glass phase. Hydrated products from the slag cement are not basically different from those from blastfurnace slag cement. The compressive strenght of high calcium slag cement is almost equal to that of blastfurnace slag and ordinary portland cement.
Effect of hydrogen pressure on the pyrolysis of coal by using a specially designed pressurized Curie-point pyrolyzer was investigated. The effects of coal type, pyrolysis temperature and catalysts, like Fe-, Ni-, and Ca-compounds, were also clarified. Raw coal and metalimpregnated coal were heated in 0.1-5 MPa hydrogen or helium at-3000°C/s to 650-920°C and the yields of char and geseous products were analyzed. In the case of raw coals, the yields of methane and BTX (benzene, toluene, xylenes) increased with hydrogen pressure and pyrolysis temperature. The effect of pressure was most remarkable with subbituminous coal and it was observed using helium instead of hydrogen. The catalytic pyrolysis of coal depended on the kinds of metal compounds as well as in the catalytic gasification. The Ni catalyst significantly increased the yield of methane. The yield of BTX was increased by the addition of Fe or Ni, but decreased by Ca. The effect of catalyst became significant with increase of hydrogen pressure. The high BTX yield was observed with Feimpregnated coal at 5 MPa. The Fe catalyst after flash hydropyrolysis was highly dispersed in the char.
The fuel cell has a special feature to convert chemical energy of fuel into electricity without use of a heat engine. In this paper, a method is proposed, in which energy conversion and exergy loss in the cell can be displayed on CRT by representing the relation between the amount of energy transformed and the energy levels of the energy donating process and energy accepting one on an Energy-Utilization Diagram (EUD). Also a simulator is developed to automatically generate EUDs by giving compositions and conditions of input streams, reactions in the cell and the exergy loss information.