The present invention provides an improved process for removing heat from an exothermic reaction. In particular, the present invention provides a process wherein heat can be removed from multiple reaction trains using a common coolant system.

A method is provided of shutting down an operating three-phase slurry bubble column reactor (10) having downwardly directed gas distribution nozzles (30) submerged in a slurry body (19) of solid particulate material suspended in a suspension liquid contained inside a reactor vessel (12), with the gas distribution nozzles (30) being in flow communication with a gas feed line (26) through which gas is fed to the gas distribution nozzles (30) by means of which the gas is injected downwardly into the slurry body (19). The method includes abruptly stopping flow of gas from the gas feed line (26) to the gas distribution nozzles (30) to trap gas in the gas distribution nozzles (30) thereby to inhibit slurry ingress upwardly into the gas distribution nozzles (30).

A procedure for shutting down a dehydrogenation reactor having a catalyst bed with a chromium-containing catalyst operating at a first elevated temperature comprises cooling the catalyst bed with a first cooling gas to a second elevated temperature lower than the first elevated temperature, removing the first cooling gas, introducing a reducing gas to the catalyst bed, cooling the catalyst bed with a second cooling gas from the second elevated temperature to a third elevated temperature, removing the reducing gas, cooling the catalyst bed to a fourth elevated temperature, and introducing air to cool the catalyst to ambient temperature, whereby the dehydrogenation reactor is shut down. The second cooling gas may be the same as, or different from, the reducing gas. Moreover, the reducing gas may be purged from the reactor by a third cooling gas.

The present invention provides an improved process for removing heat from an exothermic reaction. In particular, the present invention provides a process wherein heat can be removed from multiple reaction trains using a common coolant system.

Provided is a production device including: a first reactor to form a second gas containing an ester and nitric oxide from a first gas containing carbon monoxide, a nitrite, and nitric oxide; an absorption column to separate the second gas and an absorbing solution into a condensate containing the ester and a noncondensable gas; a second reactor to introduce an alcohol, the noncondensable gas, and oxygen gas thereinto to form a third gas containing nitric oxide and a nitrite; a third reactor to form a fourth gas containing a nitrite from the noncondensable gas and a bottom liquid from the second reactor and to feed the fourth gas to the second reactor; a first measurement unit to measure the concentration of a nitrite in the first gas; and a first flow rate-adjusting unit to adjust the amount of the noncondensable gas to the third reactor based on the concentration.

The invention relates to a method for operating a dehydrogenation reactor for the dehydrogenation of hydrocarbons is provided wherein the dehydrogenation reactor comprises a potassium promoted iron oxide catalyst, the hydrocarbons being dehydrogenated in contact with the catalyst and carbon dioxide is introduced during a) start-up of the reactor, b) shut-down of the reactor, and c) steaming procedures, wherein the carbon dioxide is introduced in conjunction with steam in at least one method step.

Provided is a production device including: a first reactor to form a second gas containing an ester and nitric oxide from a first gas containing carbon monoxide, a nitrite, and nitric oxide; an absorption column to separate the second gas and an absorbing solution into a condensate containing the ester and a noncondensable gas; a second reactor to introduce an alcohol, the noncondensable gas, and oxygen gas thereinto to form a third gas containing nitric oxide and a nitrite; a third reactor to form a fourth gas containing a nitrite from the noncondensable gas and a bottom liquid from the second reactor and to feed the fourth gas to the second reactor; a first measurement unit to measure the concentration of a nitrite in the first gas; and a first flow rate-adjusting unit to adjust the amount of the noncondensable gas to the third reactor based on the concentration.

This invention relates to methods for producing chemical products, wherein the one or more feed materials are reacted to form a chemical product or a chemical composition. The invention further relates to plants for performing such methods, said plants being designed in such a way that, during an interruption of the methods, no input of at least one feed material into the reaction occurs and the plant parts not affected by a revision measure, maintenance measure, repair measure, or cleaning measure are operated in so-called re-circulation mode. It is thereby achieved, among other things, that only the affected plant part needs to be shut down for the time of the measure, which can be advantageous with regard to the productivity and economy of the method and the quality of the produced products. Finally, the invention relates to methods for operating plants in the event that individual plant parts are taken out of service.

In the operation of an oxidative dehydrogenation (ODH) process, it is desirable to remove oxygen in the product stream for a number of reasons, including to reduce oxidation of the product. This may be achieved by having several pre-reactors upstream of the main reactor having a catalyst system containing labile oxygen. The feed passes through one or more reactors saturated with labile oxygen. When the labile oxygen is consumed through a valve system, the pre-reactor accepts product from the main reactor and complexes reactive oxygen in the product stream until the catalyst system is saturated with labile oxygen. Then the reactor becomes a pre-reactor and another pre-reactor becomes a scavenger.

A process may include shutting down a reactor in which ethylbenzene is undergoing dehydrogenation to styrene in the presence of steam and a catalyst adapted to catalyze dehydrogenation of ethylbenzene to styrene. Shutting down the reactor may include reducing a temperature of the reactor. Shutting down the reactor may include supplying a purge stream to the reactor. Supplying a purge stream may include increasing a steam-to-ethylbenzene molar ratio of an input stream to the reactor. Supplying a purge stream may include supplying steam and one or more of H.sub.2, CO.sub.2, and styrene to the reactor. The process may include stopping supply of the purge stream to the reactor and supplying an inert gas purge stream to the reactor. Shutting down the reactor may be performed without use of a steam-only purge stream.