Coal liquefaction multistage

Multistage coal liquefaction has been proposed to consist of the following stages, as shown in Fig. 1 [this scheme is the basis for promising processes... 

XIV. Design of Multistage Coal Liquefaction with Catalysts Yet to Be Developed... 

In preceding sections, fundamental coal chemistry, liquefaction mechanisms, solvent and catalyst characteristics were summarized briefly. In the following three sections, the roles and improvements in solvents and catalysts in multistage liquefaction processes are reviewed in more detail on the basis of recent progress in this area. 

The multistage liquefaction process (Figure 19.17) involves the liquefaction of crushed, dried coal which is slurried with an aromatic recycle solvent and the whole is then charged to a reactor at 415°C-440°C (VSOT-STST) at approximately 2000 psi. An expanded bed reactor system is employed to circumvent the problems that arise through reactor plugging, catalyst deactivation, and inequitable liquid distribution. 

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