Methanol, production quench reactor

In order to control heat removal and therefore the catalyst temperature, multiple-tube reactors (Lurgi process) or quench reactors with several catalyst layers and introduction of cold gas (ICI process) are mainly used. Catalyst performance in modern larger reactors is 1.3-1.5 kg of methanol per liter per hour, and large-scale plants have capacities of up to 10 fra, which reflects the position of methanol as a key product of Ci chemistry. 

A10-liter reactor was charged with 4.8 liter of toluene, heated to 70°C, and treated with triisobutylaluminum (8.4 mmol). The temperature was then increased to 90°C, and ethylene was introduced. After the pressure was stabilized at 1.1 MPa, 50 ml of a toluene solution containing the Step 2 product (0.3 mmol) and triisobutylaluminum (0.84 mmol) were added. The polymerization duration was 5 minutes. Thereafter the reaction was quenched with methanol, and 215 g of product were isolated. 

The reaction gas is cooled to ambient temperature in a water spray column, and the quench water that condenses is fed back in a closed cycle to the electric arc reactor. The gas is then compressed and subjected to a sequence of scrubbing operations with selective solvents [i.e., methanol, octane, and A/ -methyl-2-pyrrolidone (NMP) in that order]. The solvents are regenerated by low-pressure stripping with gas fractions from the production process. This removes mainly the polyunsaturated hydrocarbons. 

In contrast to methanol oxidation, oxidative dehydrogenation of methanol [route (b) in Topic 5.3.2] is an endothermic reaction (AH = -F84kJ mol ). Methanol is contacted at normal pressure with a heterogeneous silver at 500-700 °C. Owing to the kinetic instability of the formaldehyde product under the applied reaction conditions, the contact time at the catalyst is very short (t < 0.01 s). This is realized by high flow rates in the reactor and a very effective quenching of the product flow leaving the reactor. The product gas is contacted with water to produce an aqueous... 

At complete oxygen conversion, the selectivity of methanol formation in these experiments was influenced neither by changing the residence time of the mixture in the reactor nor by quenching the products at the reactor outlet. In contrast to [90], in [43], there were no signs of any oscillations as claimed by the authors, the process was stable and reproducible. In general, the heterogeneous nature of the process in this study remains the most likely explanation of its high characteristics, substantially different from the results of most other studies. 

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