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

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Figure 3: Conceptual diagrams of different types of reactors. 2.3.2.5 Commercial DME synthesis technologies Haldor Topsøe designed special fixed-bed reactor to solve temperature problems in DME production. The reaction from synthesis gas to DME is a sequential reaction, involving methanol as an intermediate. The first part of the reaction from synthesis gas to methanol is quite exothermal and it is limited by equilibrium at a fairly low temperature. Therefore, the first part of the reaction takes place in a cooled reactor, where the reaction heat is continuously removed, and the equilibrium is approached at optimum conditions. The second part of the reaction from methanol to DME is much less exothermal, and the equilibrium is limited at a different temperature. Therefore, this part of the reaction takes place in a separate adiabatic fixed bed reactor. Consequently, the two-stage reactor concept permits both parts of the sequential reaction to take place at optimum conditions, while at the same time the synthesis section becomes more similar to a conventional methanol synthesis loop. With respect to technology verification at industrial scale, the only major difference between the oxygenate synthesis and the methanol synthesis is the second stage adiabatic reactor, loaded with the proprietary Topsøe dual-function catalyst. This dual-function catalyst is a unique product, developed by Topsøe in the early 1990’s. Since then, this catalyst has been tested in excess of 30,000 hours in a Topsøe DME process demonstration unit. Due to the extensive catalyst testing and the simple adiabatic reactor configuration, the technology risk in the DME synthesis is minimal. Consequently, all the process steps have been tried and approved in industrial operation. Product separation and purification – The layout of the separation and purification section depends on the specific demands for product purity. Obviously, the lower demands for product purity, the lower investment and energy consumption. In fact, substantial savings are achieved by producing fuel grade DME, i.e. DME containing minor amounts of methanol and water. 26
Figure 4: Topsøe gas phase technology for large scale DME production. The process developed by the JFE Group (hereinafter referred to as the JFE Process) has reached a high degree of completion, and consists of the element technical development described below. Because the reaction heat in the DME synthesis reaction is large, it is necessary to remove reaction heat and perform reaction temperature control properly in order to prevent a reduction of equilibrium conversion and catalyst deactivation due to temperature rise. The JFE Process uses a slurry bed reactor in which the reaction is promoted by placing the synthesis gas in contact with the catalyst in slurry in which the catalyst is suspended in a reaction medium. Because the heat capacity and thermal conductivity of the reaction medium are both large, the reaction heat is absorbed by the reaction medium and leveling of the temperature in the reactor is easy. In their demonstration plant, efficient reaction temperature control is performed by changing the pressure of steam generated by a heat exchanger installed in the reactor. With the slurry bed reactor, it is also possible to exchange the catalyst during operation when necessary. The highest equilibrium conversion rate was achieved with the composition H2/CO = 1.0. Figure 5: JFE liquid phase technology for large scale DME production. 27
Page 1 and 2: Novel Design of an Integrated Pulp
Page 3 and 4: Table of Contents List of Figures .
Page 5 and 6: List of Figures Figure 1: Price of
Page 7 and 8: 1 Introduction The global transport
Page 9 and 10: 2 Background 2.1 Pulp Mill Backgrou
Page 11 and 12: 2.1.2.2 Chemical Pulping The most c
Page 13 and 14: sodium sulfide and sodium carbonate
Page 15 and 16: process described in the section on
Page 17 and 18: 2.2.1 Low-Temperature Black Liquor
Page 19 and 20: Figure 2: Chemrec gasification proc
Page 21 and 22: Table 3: Average syngas composition
Page 23 and 24: DME than that could be obtained fro
Page 25: U.S. Patent[58] and European Patent
Page 29 and 30: DME Workshop, Japan (Sept. 7, 2000)
Page 31 and 32: 2.4.1. Fischer-Tropsch Reactors The
Page 33 and 34: kpH 2 pCO Cobalt rate = 2 (2.4.1) (
Page 35 and 36: 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 and 88:
Appendix D: FTD Synthesis Two diffe
Page 89 and 90:
Table D.3: The hydrocarbon product
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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