Today the history of development and operation of Heavy Oil Upgrading and Coal Liquefaction processes lasts about 100 years in Germany. The two, still most famous technologies developed and commercially operated are the Fischer-Tropsch (FT) and the Bergius-Pier processes. Whilst coal liquefaction via the FT process requires initial gasification of the coal in order to recombine the derived gaseous products in the actual FT reaction (indirect coal liquefaction, “ICL”), the Bergius-Pier process derives light hydrocarbons from heavy feedstock by thermal cracking and hydrogen saturation in one step (direct hydrogenation or direct coal liquefaction, “DCL”).
As the direct coal liquefaction delivers significant higher liquid yields compared to the indirect coal liquefaction, the technical demarcation which process to use for Coal Liquefaction is essentially driven by the physical and chemical properties of the available coal. Coals with high ash contents and low volatiles require indirect liquefaction with poor liquid yields whilst coals with low ash (below ∼12% after beneficiation) and typical volatile contents (above ∼30%) deliver high liquid yields by the direct liquefaction.
The first commercial operated DCL plant utilizes in 1927 the Bergius-Pier technology. Since then the Bergius-Pier process was subject to various developments in which the process was also known as “IG-Farben Process”, “Combi Cracker” and in its latest versions “IGOR”, “DT” or “VCC”.
|1924 – 1945||Separate Hydroconversion and Hydrotreatment, “IG-Farben” process
→ (PDF Fact-sheet Bergius 1)
|1952 – 1964||Combined Hydroconversion and –treatment, „Combi Cracker“ process
→ (PDF Fact-sheet Bergius 2)
|1976 – 2000||Optimized slurry preparation in coal liquefaction mode, “DT”, “IGOR” and “VCC” process
→ (PDF Fact-sheet Bergius 3)