DIP_Class4_Reactor p. 1 Integrated Process Design (Integration) Integrated Process Design CHOICE OF REACTOR (III) Practical reactors Example

DIP_Class4_Reactor p. 2 Integrated Process Design (Integration) Choice of Reactor Practical reactors STIRRED TANK REACTORS Liquid phase, homogeneous or heterogeneous (L+L, L+S, L+G, S+L+G). Allowed reaction processes: Operation modes: Batch – Semi-batch – Continuous Non-recommended processes: Multiple in series and some in parallel (low selectivity). High pressure. Hazardous products. Temperature control: External jacket or internal coil. External heat exchanger. Reflux from condenser Recommended large volume PF reactor: consider using CSTR in series.

DIP_Class4_Reactor p. 3 Integrated Process Design (Integration) TUBULAR REACTORS Heterogeneous reactions (unless static mixers are used). Not-allowed reaction processes: Operation modes: Batch – Semi-batch. Recommended: Residence time controlled reactions (multiple in series and polymeric without termination stage). Highly exothermic/endothermic reactions. High pressure. FIXED-BED CATALYTIC REACTORS

DIP_Class4_Reactor p. 4 Integrated Process Design (Integration) ‘Hot spots’: undesired reactions and catalyst degradation Multi-tubular. Alternatives: Catalyst dilution (inert solid). Not recommended when frequent catalyst regeneration is required (alternatively a moving-bed catalytic reactor may be used).

DIP_Class4_Reactor p. 5 Integrated Process Design (Integration) FIXED-BED NONCATALYTIC REACTORS Gas + solid reactions: Non-stationary conditions: difficult to control. Gas + liquid reactions: Improve contact between phases. FLUIDIZED-BED CATALYTIC REACTORS Advantages: Excellent temperature uniformity. Continuous catalyst regeneration. Disadvantages: Complex hydrodynamic (bubbles). Attrition of catalyst. Intermediate performance between PF and CSTR models. FLUIDIZED-BED NONCATALYTIC REACTORS Gas + solid reactions (the same characteristics as catalytic reactors)

DIP_Class4_Reactor p. 6 Integrated Process Design (Integration) STIRRED TANK REACTOR TUBULAR REACTOR FIXED-BED CATALYTIC REACTOR FIXED-BED NONCATALYTIC REACTOR FLUIDIZED-BED CATALYTIC REACTOR FLUIDIZED-BED NONCATALYTIC REACTORS Gas phase reaction. Catalytic heterogeneous. Frequent catalyst regeneration. FLUIDIZED-BED TOLUENE H2H2

DIP_Class4_Reactor p. 7 Integrated Process Design (Integration) Flow pattern: Toluene: main reaction  PF H 2 :  High concentration at the exit. Benzene: multiple in series  PF Excess of hydrogen: Shifts the competitive reaction to the left (higher selectivity) Reduces coke formation. Decreases kinetics, Temperature: Main reaction: highly exothermic, irreversible  T high (control ΔT !!) Secondary reaction: endothermic, equilibrium  T low at the exit Inert: Control ΔT (cold-shot and mC p increase) Pressure:Main reaction : irreversible  P maximum Secondary reaction: equilibrium Δn=0  indifferent Separate from CH 4 to recycle.