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Unformatted text preview: REACTOR DESIGN IMPORTANCE OF REACTOR A reactor is a vessel used to carry out the desired reaction under a controlled set of conditions. This unit is said to be the heart of the process industry, and in fact, all the other units usually act as its auxiliaries. Depending upon their mode of operation, the reactors are either batch or continuous. Continuous reactors are further classified as mixed­flow reactors (MFR) and plug­flow reactors (PFR). Selection of reactor The selection of best reactor type for a given process must consider; Temperature and pressure of reaction Phases involved in process Need for removal or addition of reactants and products Require pattern of product delivery (continuous or batch wise) Limitation of reactor type Relative cost of reactor Equipment Selection As our process is continuous process rate because production rate >5.00^5 Kg/ year we only consider reactors for continuous and heterogeneous processes as gas and solid phases are present. Reactors are; 1­Fixed and Fluidized bed reactors 2­Trickle bed reactors Comparison between fixed bed and Comparison trickle bed reactor trickle Comparison between fixed bed and Comparison fluidized bed reactors fluidized Comparing parameters Residence Time Distribution Pressure Drop Catalyst handling Catalyst Consumption Maximum Volume Maximum Working Pressure Process flexibility Investment Costs Catalyst Partial Fluidized Bed (Slurry) Good Mixing Low or medium Technical difficulties Possible 50 m3 10 MPa Batch or Continuous High Highly active Fixed Bed Plug Flow high None No Loss 300 m3 High Pressure Possible Continuous Low Supported, good thermal stability and long working life Operating Cost High Low Comparison between different Comparison operations of fixed bed reactors operations Classification Single adiabatic bed Use Moderately exothermic or endothermic non-equilibrium limited Where low AP is essential and useful where change in moles is large High conversion, equilibrium limited reactions Typical Applications Mild hydrogenation Radial flow Styrene from ethylbenzene Adiabatic beds in series with intermediate cooling or heating SO2 oxidation Catalytic reforming Ammonia synthesis Hydro cracking Styrene from ethylbenzene Many hydrogenations Production of Benzene derivatives Ethylene oxidation to ethylene oxide, formaldehyde by methanol oxidation, phthalic anhydride production Steam reforming Multi-tabular non-adiabatic Highly endothermic or exothermic reactions requiring close temperature control to ensure high selectivity Direct-fired non-adiabatic Highly endothermic, high temperature reactions Material balance around the reactor 6 Stream no. Total material input (kg/hr ) Total material output(kg/h r ) 4 4 1558.5 ­­­­­­ REACTOR 5 5 6 7 7 37202.4 ­­­­­­­­ 8 ­­­­­­ 28973.0 0 ­­­­­­­ 54467.9 4 ...
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