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.

A gas phase polymerization process is described that includes contacting a polymer seed bed with a desiccant. The gas phase polymerization process further includes introducing a polymer seed bed into a gas phase polymerization reactor, contacting the polymer seed bed with a desiccant, and introducing a polymerization catalyst into the gas phase polymerization reactor. Also described is a gas phase polymerization process in accordance with the present disclosure that includes subjecting a polymer seed bed to startup conditions in a gas phase polymerization reactor, monitoring a moisture content of a vapor in contact with the polymer seed bed, and introducing a desiccant into the gas phase polymerization reactor to maintain the moisture content below a desired moisture content, to reduce a moisture content that is above a desired moisture content, or both.

A start-up method for contacting a feed stream with fluidized catalyst is disclosed. The start-up method comprises reacting a feed stream over a catalyst to produce a gas stream and spent catalyst. The gas stream is separated from the spent catalyst. The separated gas stream is passed to a compressor. The operating condition associated with the compressor is measured. Based on the measured operating condition associated with the compressor, one or both of a supplemental hydrocarbon stream and a supplemental hydrogen gas stream is provided to the compressor to meet a predetermined operating condition associated with the compressor.

A method for charging a catalyst into a reactor (40) comprising a separation loop (21), comprising the following steps: a) filling the reactor (40) with a solvent S1; b) filling the separation loop (21) with said solvent S1; c) causing said solvent S1 to move in the synthesis reactor (40) and the separation loop (21); d) heating the reactor (40) to a temperature of 100 C. or less; e) injecting an inert gas into the bottom of the reactor (40); f) mixing said catalyst with a solvent S2 in a vessel (30) in order to obtain a liquid/solid mixture; g) increasing the pressure in the vessel (30) then sending the liquid/solid mixture to the reactor (40); h) withdrawing said solvent S1 and/or S2.

Methods and apparatus are disclosed for triggering and maintaining an exothermic reaction in a reaction material comprising a metal occluded with hydrogen. The reaction material is prepared by loading a hydrogen absorbing material, e.g., a transition metal, with a hydrogen gas that comprises one or more of hydrogen isotopes. Different conditions and system configurations for triggering the exothermic reaction are also disclosed.

Method for switching between steady-state and non-steady-state operations of a process for the production of a polymer by polymerization of a monomer in the presence of a comonomer and/or hydrogen. The process includes (a1) at non-steady-state controlling the process based on the ratio of comonomer to monomer in the reactor, and (b1) at steady-state controlling the process based on the flow ratio of comonomer to monomer to the reactor, and/or (a2) at non-steady-state controlling the process based on the ratio of hydrogen to monomer in the reactor, and (b2) at steady-state controlling the process based on the flow ratio of hydrogen to monomer to the reactor.

The invention relates to a method for start-up and operation of a Fischer-Tropsch reactor comprising the steps of: (a) providing a reactor with a fixed bed of reduced Fischer-Tropsch catalyst that comprises cobalt as catalytically active metal; (b) supplying a gaseous feed stream comprising carbon monoxide and hydrogen to the reactor, wherein the gaseous feed stream initially comprises a nitrogen-containing compound other than molecular nitrogen in an initial concentration in the range of from 0.1 to 50 ppmv based on the volume of the gaseous feed stream; (c) converting carbon monoxide and hydrogen supplied with the gaseous feed stream to the reactor into hydrocarbons at an initial reaction temperature, wherein the initial reaction temperature is set at a value of at least 200 C. and hydrocarbons are produced at a first yield; (d) maintaining the initial reaction temperature at the set value and maintaining the first yield by decreasing the concentration of the nitrogen-containing compound in the gaseous feed stream supplied to the reactor; (e) optionally increasing the reaction temperature after the concentration of the nitrogen-containing compound in the gaseous feed stream has decreased to a value below 100 ppbv.

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.

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.

The invention relates to a method for start-up and operation of a Fischer-Tropsch reactor comprising the steps of: (a) providing a reactor with a fixed bed of reduced Fischer-Tropsch catalyst that comprises cobalt as catalytically active metal; (b) supplying a gaseous feed stream comprising carbon monoxide and hydrogen to the reactor, wherein the gaseous feed stream initially comprises a nitrogen-containing compound other than molecular nitrogen in an initial concentration in the range of from 0.1 to 50 ppmv based on the volume of the gaseous feed stream; (c) converting carbon monoxide and hydrogen supplied with the gaseous feed stream to the reactor into hydrocarbons at an initial reaction temperature, wherein the initial reaction temperature is set at a value of at least 200 C. and hydrocarbons are produced at a first yield; (d) maintaining the initial reaction temperature at the set value and maintaining the first yield by decreasing the concentration of the nitrogen-containing compound in the gaseous feed stream supplied to the reactor; (e) optionally increasing the reaction temperature after the concentration of the nitrogen-containing compound in the gaseous feed stream has decreased to a value below 100 ppbv.