Coal processing

Table 7. Properties of Syncrude from H-Coal Process ...

G. A. Johnson and co-workers, "Present Status of the H-Coal Process," paper 30, IGT Coal Symposium, Chicago, 1973. 

Based on the bench-scale data, two coal-to-acetylene processes were taken to the pilot-plant level. These were the AVCO and Hbls arc-coal processes. The Avco process development centered on identifying fundamental process relationships (29). Preliminary data analysis was simplified by first combining two of three independent variables, power and gas flow, into a single enthalpy term. The variation of the important criteria, specific energy requirements (SER), concentration, and yield with enthalpy are indicated in Figure 12. As the plots show, minimum SER is achieved at an enthalpy of about 5300 kW/(m /s) (2.5 kW/cfm), whereas maximum acetylene concentrations and yield are obtained at about 7400 kW/(m /s) (3.5 kW/cfm). An operating enthalpy between these two values should, therefore, be optimum. Based on the results of this work and the need to demonstrate the process at... 

The economics of the arc-coal process is sensitive to the electric power consumed to produce a kilogram of acetylene. Early plant economic assessments indicated that the arc power consumption (SER = kwh/kgC2H2) must be below 13.2. The coal feedcoal quench experiments yielded a 9.0 SER with data that indicated a further reduction to below 6.0 with certain process improvements. In the propane quench experiment, ethylene as well as acetylene is produced. The combined process SER was 6.2 with a C2H2/C2H4 production ratio of 3 to 2. Economic analysis was completed uti1i2ing the achieved acetylene yields, and an acetylene price approximately 35% lower than the price of ethylene was projected. 

R. E. Gannon and V. Kmkonis, "Arc-Coal Process Development," ReTD Report No. 34—Fina/Report, ContractNo. 14-01-0001-493, prepared for Office of Coal Research by AVCO Corp., 1972. 

British Coal Corp. is developing a gasoline-from-coal process at a faciUty at Point of Ayr (Scotiand). This process involves treatment with Hquid recycle solvents, digestion at 450—500°C, filtration to separate unconverted residues, and separation into two fractions. The lighter fraction is mildly hydrotreated, and the heavier one is hydrocracked (56). 

The term tar sands is a misnomer tar is a product of coal processing. Oil sands is also a misnomer but equivalent to usage of "oil shale." Bituminous sands is more correct bitumen is a naturally occurring asphalt. Asphalt is a product of a refinery operation, usually made from a residuum. Residuum is the nonvolatile portion of petroleum and often further defined as atmospheric (bp > 350° C) or vacuum (bp > 565° C). For convenience, the terms "asphalt" and "bitumen" will be used interchangeably in this article. 

Goal Processing to Synthetic Fuels and Other Products. The primary approaches to coal processing or coal conversion are thermal decomposition, including pyrolysis or carbonization (5,6), gasification (6), and Hquefaction by hydrogenation (6). The hydrogenation of coal is not currently practiced commercially. 

Several processes progressed to demonstration scales but have not been commercialized, primarily because of economic inabiHty to compete with available petroleum products. The H-Coal process developed by Hydrocarbon Research, Inc. was demonstrated at Catiettsburg, Kentucky using a 545 t/d plant and DOE support. The Exxon donor solvent Hquefaction process was not commercialized either. 

R. E. Hucko and co-workers, "Status of DOE-sponsored Advanced Coal Cleaning Processes," ia R. R. K1 impel and P. T. Luckie, eds.. Industrial Practice of Fine Coal Processing, SME, Inc., Littieton, Colo., 1989. 

Solvent Refined Coal Process. Work ia the mid-1960s by the Speacer Chemical Co. (9) and dating the 1970s by the Gulf Chemical Corp. led to two solvent refined coal (SRC) processiag schemes SRC-I for productioa of low ash soHd boiler fuels and SRC-II for distillates, eg, "syn-cmde."... 

The SRC-II process, shown in Figure 2, was developed in order to minimise the production of soHds from the SRC-I coal processing scheme. The principal variation of the SRC-II process relative to SRC-I was incorporation of a recycle loop for the heavy ends of the primary Hquefaction process. It was quickly realized that minerals which were concentrated in this recycle stream served as heterogeneous hydrogenation catalysts which aided in the distillate production reactions. In particular, pyrrhotites, non stoichiometric iron sulfides, produced by reduction of iron pyrite were identified as being... 

The H-Coal process could operate in one of two modes, depending on the desired product slate. In the "syn-cmde" mode, a fluid-bed coking unit was employed to maximize recovery of distillate from the Hquefaction product (Fig. 7a). When operated in the fuel oil mode (Fig. 7b), no coker was used and the primary product was a coal-derived low sulfur fuel oil. Total hydrogen demand on the process was also reduced in the latter mode of operation. 

Fig. 7. H-Coal process using Illinois No. 6 coal (a) in syncmde mode, and (b) in low sulfur fuel oil mode. To convert to Btu, multiply by 6.48 x lO ". To convert m to bbl, multiply by 6.29. To convert m to standard cubic feet (SCF), multiply by 35.3...

Owen, J., Liquefaction of coal. In Coal and Modern Coal Processing- An Introduction, ed. G. J. Pitt and G. R. Millward. Academic Press, New York, 1979, pp. 163 181. 

Rodgers, N.L., In Proc. Conf. Specialized Cleaning, Finishing and Coaling Processes. American Society tor Metals, Los Angeles, CA, Feb. 1980. pp. 63-77,... 

The flotation process was developed in the mining and coal processing industries as a way of separating suspended solids from a medium such as water. As noted above, the flotation process has found uses in other fields, such as wastewater treatment. The process introduces fine air bubbles into the mixture, so that the air bubbles attach to the particles, and lift them to the surface. 

When optimizing industrial ventilation, the real consequences for the environment due to decisions made are of interest. Therefore, the marginal effect on the whole energy system is what is required. This is of course difficult. Many practitioners use electricity produced from coal processes as marginal, but some use natural-gas-fired power plants. It depends mainly on the area and time frame that is being considered. 

Group 3 elements which are not mostly vaporized in the boiler (1423 K) V, Cr, Mn, Co, Ni Referring to the classification, we investigated the temperature dependency of release of trace metals in coal combustion. We already reported the behavior of these three types of elements during high temperature coal processing and reported elsewhere . So in this paper, we investigated the effect of atmosphere for the emission behavior of trace elements. 

Hooks, H.W. Boykin, R.G., Solvent Refined Coal Process Quarterly Technical Progress Report for the period January-March 1978, from Catalytic Inc. to EPRI and DOE, July 1978. 

The development of three-phase reactor technologies in the 1970 s saw renewed interest in the synthetic fuel area due to the energy crisis of 1973. Several processes were developed for direct coal liquefaction using both slurry bubble column reactors (Exxon Donor Solvent process and Solvent Refined Coal process) and three-phase fluidized bed reactors (H-Coal process). These processes were again shelved in the early 1980 s due to the low price of petroleum crudes. 

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