The present invention relates to a process for the polymerization of olefin monomers in the presence of a catalyst system, using a tubular pre-polymerization reactor, wherein the tubular pre-polymerization reactor has a length L and the flow of a catalyst system is introduced in the tubular pre-polymerization reactor in the middle (30-70% of L) or the end (70-95% of L) of the tubular pre-polymerization reactor.

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.

Processes for activating precious metal-containing catalysts. The processes can decrease the amount of high purity hydrogen required for starting up a catalytic conversion process such as transalkylation of heavy aromatics, without detrimental impact to the metal activity. The processes can include a low temperature treatment step with a high purity first gas, such as hydrogen generated by electrolysis and/or reformer hydrogen diluted with high purity inert gas, and a high temperature treatment step with a low purity second gas such as the reformer hydrogen. Also, the processes can include mixing a hydrogen gas of high or low purity with a high purity inert gas to form a gas mixture with a proportion of hydrogen no less than 2% and a reduced carbon monoxide concentration relative to the low purity hydrogen, and contacting the catalyst with the gas mixture.

A hydroformylation process can be used for short-chain olefins, especially C2 to C5 olefins, wherein the catalyst system is heterogenized on a support that contains a porous ceramic material. Systems can also be used for carrying out said process.

A hydroformylation process can be used for short-chain olefins, especially C2 to C5 olefins, wherein the catalyst system is heterogenized on a support that contains a porous ceramic material. Systems can also be used for carrying out said process.

The present invention relates to a preheating process and a start-up process for the ammoxidation reaction. The preheating process or the start-up process at least includes the step of heating the catalyst bed in the ammoxidation reactor while controlling the reactor operation linear speed to 0.03-0.15 m/s. The start-up process of the present invention has the advantages such as the significantly reduced launch time compared with the prior art and the operation safety.

Processes for activating precious metal-containing catalysts. The processes can decrease the amount of high purity hydrogen required for starting up a catalytic conversion process such as transalkylation of heavy aromatics, without detrimental impact to the metal activity. The processes can include a low temperature treatment step with a high purity first gas, such as hydrogen generated by electrolysis and/or reformer hydrogen diluted with high purity inert gas, and a high temperature treatment step with a low purity second gas such as the reformer hydrogen. Also, the processes can include mixing a hydrogen gas of high or low purity with a high purity inert gas to form a gas mixture with a proportion of hydrogen no less than 2% and a reduced carbon monoxide concentration relative to the low purity hydrogen, and contacting the catalyst with the gas mixture.

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.

The present invention relates to a preheating process and a start-up process for the ammoxidation reaction. The preheating process or the start-up process at least includes the step of heating the catalyst bed in the ammoxidation reactor while controlling the reactor operation linear speed to 0.03-0.15 m/s. The start-up process of the present invention has the advantages such as the significantly reduced launch time compared with the prior art and the operation safety.

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.