Novel Design of an Integrated Pulp Mill Biorefinery for the ...

The clean syngas to Fischer-Tropsch productions portion of the Steinberg’s case study
was scaled down to provide mass flow rates for the FTD design. Though Steynberg et al. case
study provides a mass and energy balance, assumptions and back calculations were necessary to
provide adequate data to scale down the design. The syngas gas used in the Steynberg et al. case
study is given in Table D.2. Using the mole % data giving in Table D.2, and the volumetric flow
rate of clean syngas from Table D.1, the mass flow rate of syngas from the Steynberg et al. case
study was calculated to be 395.5 kg/s.
Table D.2: Syngas gas used in the Steynberg et al. case study [72].
Species mole %
29.26
H 2
CO 37.36
CO2 13.3
0.16
CH 4
H 2O 19.43
Inert 0.49
Table D.1 shows the Steynberg et al. design produce 18248 bbl/day of hydrocarbon
condensate and 35844 bbl/day of wax. The hydrocarbon condensate is assumed to be
hydrocarbon chains from C5 to C20 and the wax is assumed to be C20+ hydrocarbon chains. The
hydrocarbon condensate would make up 30.6 % of the FT products and wax would make up
69.4%. These product percentages correspond to an α of 0.94 on a Anderson-Schultz-Flory
distribution, given in Figure D.2. The hydrocarbon chain product produced from an α of 0.94 are
given in Table D.3. Though Steynberg et al. did not account for C1 to C4 products; they are
produced and are part of the tailgas. Using an α of 0.94 assumes that approximately 2% of the
FT-products will be C1 to C4. Thus, it was assumed that the Steynberg et al. design used α of
0.94 and this product distribution was then used for the FTD design of this project.
Figure D.2: Anderson-Schultz-Flory distribution, with plots of calculated selectivities (% carbon atom basis)
of carbon number product cuts as a function of the probability of chain growth. The red lines indicate
products for an α of 0.94
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