化学工艺学Chapt_6 Hydrogenation and dehydrogenation process.ppt

* * * * * * * Basic steps of process flow for ethyl benzene dehydrogenation to prepare styrene Reactor Separator of oil and water EB distillation B and T distillation B and T separation Cooler Off-gas H2 etc. styrene EB recycle Benzene Toluene Styrene rectification Tar, heavy ends Water recycle Preheating EB steam 1. Reaction types of hydrogenation and dehydrogenation, and general rules of hydrogenation and dehydrogenation. Hydrogenation reaction is reversible exothermic process, factors affecting the reaction rate have temperature, pressure, hydrogen ratio, and the structure of hydrogenation material. Dehydrogenation reaction is endothermic reaction △H0, the equilibrium constant increases, and equilibrium conversion increases with the reaction temperature increasing. Summary of key content 2. Synthetic ammonia preparation by nitrogen hydrogenation, and equilibrium conversion and reaction rate increase with the pressure increasing, and ammonia synthesis reaction is reversible exothermic reaction, so there is the most appropriate reaction temperature, and the ratio of hydrogen to nitrogen (H2/N2) is 3 at the best equilibrium ammonia content, and the production capacity increases with space velocity increasing. Catalyst of ammonia synthesis is Fe3O4/ Al2O3/ K2O Fe3O4 must be reduced to α-Fe before using catalyst Al2O3 is structure type promoter, it can improve the structure of reduced iron K2O is electron type promoter, it is favorable for the adsorption and activation of N2. Typical ammonia synthesis loop arrangements is as follows: 3. Basic principle of methanol synthesis CO2 + 3H2 CH3OH(g) + H2O(g) CO2 + 3H2 CO + H2O CO + 2H2 CH3OH 催化剂 Main reactins: Side reactins: 2CO + 4H2 (CH3)2O + H2O CO + 3H2 CH4 + H2O 4CO + 3H2 C4H9OH + 3H2O CO2 + H2 HCHO Producing hydrocarbon 2CO + 2H2 CH4 + CO2 CO2 + 4H2 CH4 + 2H2O 2CO + 5H2 C2H6 + 2H2O nCO + (2n+1)H2 Cn H2n+2 + nH2O Producing alcohol 2CO + 4H2 C2H5OH + H2O Producing formalde