Coal liquefaction process diagram

Background Indirect coal liquefaction differs fundamentally from direct coal liquefaction in that the coal is first converted to a synthesis gas (a mixture of H2 and CO) which is then converted over a catalyst to the final product. Figure 27-9 presents a simplified process flow diagram for a typical indirect coal liquefaction process. The synthesis gas is produced in a gasifier (see a description of coal gasifiers earlier in this section), where the coal is partially combusted at high temperature and moderate pressure with a mixture of oxygen and steam. In addition to H2 and CO, the raw synthesis gas contains other constituents (such as CO2, H2S, NH3, N2, and CH4), as well as particulates. 

Figure 12.2. Diagram of the direct coal liquefaction process. ASU, air separation unit.

Direct-Liquefaction Processes Figure 27-8 presents a simph-fied process flow diagram of a typical direct coal liquefaction plant. Specific processes are described in the following paragraphs. 

A SIMPUFIED DIAGRAM OF A COAL UQtlEFACTlON PROCESS Figure 8.6 Coal-liquefaction jKocess (Warren et al.. 1995. Courtesy of ASCE),... 

Although SRC-II was basically a thermal liquefaction process, it was most successful using bituminous coals with a high native pyrite content. Iron sulfides are well known to have catalytic properties for coal liquefaction. Recycling part of the ash-minerals-containing bottoms had two beneficial effects (1) it increased the pyrite concentration in the reactor feed, and (2) it increased the residence time for heavy components, thus giving them more time to hydrocrack to distillate products. A block flow diagram of the SRC-II process is shown in Fig. 19.19. 

Fig. 13.33. Simplified energy-efficiency diagram for coal as the primary fuel for traction through liquefaction and electricity generation. The figures on each line are the approximate efficiencies for each process. The value of 0.8 for the storage and distribution of electrical energy contains the contribution from the efficiency of charging equipment. The value of 0.6 for the secondary battery (accumulator) combines the efficiency for storage (0.67) and electrical drive (0.9). (Reprinted from C. H. Hamann, A. Hamnett, and W.

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