Übersetzung für "Durchgehende reaktion" in Englisch

A runaway reaction leads to undesired secondary reactions such as, for example, the polymerization of the olefin, but at least to damage to the catalyst system.

The term ‘runaway’ of the reaction is used here.

The monolithic catalysts do not in any event have a tendency to produce a runaway reaction.

This is referred to as a “runaway” reaction.

This process has the great disadvantage that the oxygen treatment of the catalyst, which may be pyrophoric, has to be carried out under strictly controlled conditions in order to avoid a runaway reaction, ie. an uncontrolled rise in temperature, since at higher temperatures there is a danger of the catalyst being damaged through a change in its lattice structure.

Even in the presence of relatively high contents of underoxidation products together with a high concentration of PA, no runaway reaction occurs when using the catalysts of the invention.

There is no possibility of uncontrolled reaction “runaway” provided the amount of catalyst added does not exceed the customary level by a multiple.

In the extreme case, the attempt to achieve high space-time yields may lead to a runaway reaction.

Where glass apparatuses are used, a possible fracture of the reflux condenser and penetration of cooling water into the reaction space does not cause a runaway reaction.

After about 7 hours, the reactor is no longer controllable, so that a runaway reaction can be prevented only by rapidly adding a solution containing inhibitor (hydroquinone monomethyl ether).

This arrangement not only affords an elegant possibility of controlling the water amount supplied to the reaction but can also be operated with high safety because on overshooting of the reaction in the reactor 64, which manifests itself in a pronounced temperature increase, via the bypass conduit 68 carbon dioxide gas which is not directly charged with water vapor can be supplied to the reactor to retard the reaction.

A comparison of the differences between the temperature profiles of the two types of thermometer tubes can tell whether or not there are indications of a thermal runaway of the reaction.

Particularly when the gas mixture concerned has a high hydrocarbon concentration and/or high oxygen content and the catalyst requires a high light-off temperature, there is a potential risk of a runaway reaction.

The layers deposited on the work piece surfaces will be quite rough and not completely insulating since there is obviously no continuous reaction of the many metal splashes.

If the reaction rate is successfully increased by improving the mass transfer, obviously, more heat must be dissipated, which can lead to an unwanted temperature increase up to reaction runaway.

Once the reaction rate has been successfully raised by improving the mass transfer, more heat will naturally have to be removed as well, which can lead to an undesirable temperature increase and even cause a reaction to run away.

Thus, the reaction proceeds very slowly at 145–155° C., while from 180° C. on, the rate of addition must be slowed down by cooling the reactor, and from 190° C. on, there is a risk of uncontrolled reaction due to overheating, merely resulting in impure, brown products.

The “worst case” amount is the maximum amount of monomers which can be permitted to run into the reactor without occurrence of a polymerization reaction while still leading to conditions within the safety margins in the case of a runaway reaction.

They do, however, show, for example, that the highest pressure p AD occurring in the event of an adiabatic runaway reaction can be reached even before the end of the adiabatic reaction, i.e. before the maximum temperature T AD, is reached, and that subsequently a drop in the pressure can even occur.

It is an object of the present invention to develop a process for preparing maleic anhydride by heterogeneously catalyzed gas-phase oxidation of a hydrocarbon having at least four carbon atoms by means of oxygen, which is unproblematical in terms of safety in respect of a runaway reaction and which also makes possible a high conversion, a high selectivity and a high yield of desired product and therefore a high space-time yield even at a high space velocity of hydrocarbon over the catalyst over a long period of time of from several months to some years and avoids or at least greatly reduces premature damage to the catalyst.

DE-A 30 06 894 likewise concerns, in a heterogeneously catalyzed gas-phase partial oxidation process for propylene, the problems of, on the one hand, preventing a runaway reaction and, on the other hand, achieving a productivity which is as high as possible (p.

The exothermic nature of the reaction may therefore result in the incidence of what are called hotspots, leading at its most favourable to products which are non-unitary and non-reproducible, but which in the worst case may entail the runaway of the reaction in the sense of an unwanted polymerization.