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

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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 88
Table D.3: The hydrocarbon product extrapolated to be produced from Steynberg et al. case study, in percent weight. α = 0.94 C20+ 70 C12-C20 17 C5-C11 11 C1-C4 2 total 100 FT-product upgrading via hydrocracking of wax is achieved at ~400 o C with the addition of a small amount of hydrogen. However, Steynberg et al. stated that “product upgrading units have a negligible impact on the utility systems[72].” Thus, product upgrading was assumed to be a “black box” with an input of wax going in and a distribution of upgraded products coming out with no effect on the efficiency of the system. Rytter et al. reported hydrocracking of wax to yelled 80% diesel, 15% Naphtha and 5% C1-C4 gases [106]. These values were used to calculating the FT-production distribution for the FTD design. The efficiency from clean syngas to FT-product in Steynberg et al. case study is 55%. However, the syngas used by Steynberg et al. was more energetic than that for this design, having a LHV of 15.5 MJ/kg compared to 11.7 MJ/kg. To account for this, the FT-reactor for this project’s design yields a lower mass flow rate even at the scaled down rate, so that the design would have an efficiency of 55% while using a syngas LHV of 11.7 MJ/kg. The Steynberg et al. case study was based on 395.5 kg/s of clean syngas using two sets of first stage reactors followed by second stage reactors with all four reactors running at maximum output. The Steynberg et al. case study uses the minimum feasible scale of this reactor combination. This project’s FTD design is based on 123 kg/s of clean syngas. Thus, the Steynberg et al. reactors will provide a system’s efficiency that is not realist for a system scaled down to utilize 123 kg/s of clean syngas. So the efficiency of the Steynberg et al. case study is greater than that of any possible efficiency for a 123 kg/s of clean syngas design, but will provide insight to the true efficiency. Table D.4 Figure D.3 are the mass and energy balance of Steynberg et al. case study and a possible FTD design for this project. The FTD design is scaled down from the Steynberd et al. case study at a factor 0.21. The scale is based on the energy flow of the Steynberg et al. case study’s syngas to that of this project’s syngas. 89
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Novel Design of an Integrated Pulp
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Table of Contents List of Figures .
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List of Figures Figure 1: Price of
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1 Introduction The global transport
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2 Background 2.1 Pulp Mill Backgrou
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2.1.2.2 Chemical Pulping The most c
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sodium sulfide and sodium carbonate
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process described in the section on
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2.2.1 Low-Temperature Black Liquor
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Figure 2: Chemrec gasification proc
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Table 3: Average syngas composition
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DME than that could be obtained fro
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U.S. Patent[58] and European Patent
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Figure 4: Topsøe gas phase technol
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DME Workshop, Japan (Sept. 7, 2000)
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2.4.1. Fischer-Tropsch Reactors The
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kpH 2 pCO Cobalt rate = 2 (2.4.1) (
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invention of Fischer-Tropsch in the
Page 37 and 38: Table 7: hydrocarbons and associate
Page 39 and 40: 3 Process Design 3.1 Pulp Mill 3.1.
Page 41 and 42: carbonate is fired in a lime kiln t
Page 43 and 44: lost and the pulp that provides tha
Page 45 and 46: Table 16: General operating paramet
Page 47 and 48: Table 19: Ash analysis of Pittsburg
Page 49 and 50: Table 22: Experimental syngas compo
Page 51 and 52: 3.2.5 Process Options and Flexibili
Page 53 and 54: Nitrogen compounds Nitrogen from th
Page 55 and 56: 3.3.2.3 Reactors A single-step gas
Page 57 and 58: Table 27: FT-diesel fuel synthesis
Page 59 and 60: 3.5.2 Power Generation Process Desi
Page 61 and 62: Figure 21: Schematic of biorefinery
Page 63 and 64: ar) reacts with the fuel in the com
Page 65 and 66: Figure 25showed the detailed energy
Page 67 and 68: 4. Design Summary The DME design an
Page 69 and 70: Figure 27: Mass and energy flow of
Page 71 and 72: References 1. Åhman, M., G. Modig,
Page 73 and 74: 42. R.A. Peascoe, J.R.K., C.R. Hubb
Page 75 and 76: PerformanceSimulation. 2006, Prince
Page 77 and 78: Appendix Appendix A MP Steam Demand
Page 79 and 80: Appendix B: Composite Fuel Blend to
Page 81 and 82: DME Density = 0.67 kg/L (at 20 °C)
Page 83 and 84: Air Separation Unit Requirements Ba
Page 85 and 86: Purge gas: CO conversion is 60%, 40
Page 87: Appendix D: FTD Synthesis Two diffe
Page 91 and 92: Figure D.3 Mass and energy balance
Page 93 and 94: Table D.3 Mass and energy balance o
Page 95 and 96: Appendix E: Heat and Power Generati
Page 97 and 98: Energy H2O absorbed MW 46.71 Using
Page 99 and 100: Combustion 2CO+O2→ 2CO2 + 566 kJ/
Page 101 and 102: Specific Heat (cp) b kJ/kgK 1.072 E
Page 103 and 104: Specific Heat of Steam (cp) kJ/kgK
Page 105: Appendix F: Concept Map 105
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