Hydrogen continued coals

The coals were crushed 80% less than 75 jjlm. The solvents used were anthracene oil (ex British Steel Corporation), hydrogenated process solvent (produced in a continuous coal extract hydrogenation plant) and several pure organic compounds (ex Koch-light). 

Schematic diagram of the continuous experiment high-pressure reactor. (Adapted from Shiying, L., Michiaki, H., Yoshizo, S., and Hiroyuki, H., Continuous Experiment Regarding Hydrogen Productionby Coal/ CaO Reaction with Steam (HyPr-RING), 21st Pittsburgh Coal Conference, Osaka, Japan, Sep. 13-17,2004.)...

Figure 1 Space-time-yield (volume/volume reactor/100 hours) of gasoline and middle oil for brown and bituminous coals as a function of composition of starting coal. Data from continuous coal hydrogenation facilities operating in Germany during the 1930 s.

Coal gas is the product of slow distillation of coal with exclusion of air. Blast-furnace gas results from the combustion of coal in a restricted supply of air its ideal composition would be, by weight, CO, 34.4 N, 65.6. Water gas is made by the action of steam on incandescent coal, and should consist ideally of H and CO only the process is necessarily intermittent. Producer gas is a combination of blast-furnace gas and water gas, the supply of steam being so limited as to permit of a continuous process. In all of the manufactured gases, the hydrocarbons (CH4, CeHe, C2H4) come from the coal either directly or as the result of a breakdown of other hydrocarbons. The hydrogen in coal gas and blast-furnace gas has a similar origin. The CO and CO2 in coal gas are due to a partial (and objectionable) combustion of the carbon in the coal. 

Char from the hydrogenation of coal in dilute phase was hydrogenated continuously in a moving bed at 3000 and 1500 p.s.i.g. The objective was to determine the hydrogen feed ratio that would produce an effluent gas of a certain selected composition for a particular conversion. 

So it is not surprising that the interest in the hydrogenation of coal has focused, and continues to focus, on the production of liquids as suitable alternates to petroleum feedstocks (Krichko and Gagarin, 1990) (Chapters 18, 19, and 26). Chemical hydrogenation has seen some use in structural interpretations but (unless there is some means by which it can be related to commercial interests) been largely ignored in terms of coal utilization. 

About one half of the coal samples used in the above study (61) have been investigated by workers in Gulf Research and Development Company, using a continuous flow reactor (63). The throughput was about 1 kg./h of coal/solvent slurry, the solvent was a partly hydrogenated anthracene oil, temperatures of 440 and 455°C were used, and the system was pressurized with hydrogen to 20.69 MPa. 

The reactive role of liptinite macerals in liquefaction has been partially documented (50,68). However, recent work has shown that unaltered sporinite often is encountered in the residues from both batch and continuous liquefaction runs. For example, sporinite was a common component in the residues of a high volatile A bituminous coal after hydrogen-transfer runs at 400° for 30 minutes (70). In spite of the relative unreactivity of the sporinite in this instance, the vitrinite clearly had reacted extensively because vitroplast was the predominant residue component. The dissolution rate of sporinite from some coals, even at 400°C, may be somewhat less than that of vitrinite. 

The Effect of Residence Time The final parameter that was studied was the solid residence time. In the semi-continuous reactor used for this study, the volatile product is swept from the reactor by a continuous stream of hydrogen and, therefore, there is both a vapour and solid residence time. It is this latter parameter that has been studied here and the solid residence time was considered to be the time that the reactor spends at temperature. For the study of the residence time, tin (1 % of the coal) as stannous chloride was used as the catalyst and the other conditions are given in Table II. 

---