The present invention relates to a process for producing butadiene from ethanol, in two reaction steps, comprising a step a) of converting ethanol into acetaldehyde and a step b) of conversion into butadiene, said step b) simultaneously implementing a reaction step and a regeneration step in (n+n/2) fixed-bed reactors, n being equal to 4 or a multiple thereof, comprising a catalyst, said regeneration step comprising four successive regeneration phases, said step b) also implementing three regeneration loops.

A method is provided comprising exposing a supported heterogeneous metathesis catalyst to an olefin compound for an activation time at an activation temperature; exposing the activated supported heterogeneous metathesis catalyst to a reactant capable of undergoing a metathesis reaction for a reaction time at a reaction temperature to produce metathesis products; and exposing the deactivated supported heterogeneous metathesis catalyst to a regenerating compound for a regeneration time at a regeneration temperature. The activity of the regenerated supported heterogeneous metathesis catalyst may be substantially the same or greater than the activity of the activated supported heterogeneous metathesis catalyst prior to deactivation. The activation temperature may be greater than the reaction temperature. The regenerating compound may be a second olefin compound or an inert gas.

A method is provided comprising exposing a supported heterogeneous metathesis catalyst to an olefin compound for an activation time at an activation temperature; exposing the activated supported heterogeneous metathesis catalyst to a reactant capable of undergoing a metathesis reaction for a reaction time at a reaction temperature to produce metathesis products; and exposing the deactivated supported heterogeneous metathesis catalyst to a regenerating compound for a regeneration time at a regeneration temperature. The activity of the regenerated supported heterogeneous metathesis catalyst may be substantially the same or greater than the activity of the activated supported heterogeneous metathesis catalyst prior to deactivation. The activation temperature may be greater than the reaction temperature. The regenerating compound may be a second olefin compound or an inert gas.

A process of catalytically dehydrogenating an alkane to an alkene, using Cr.sub.2O.sub.3 as a catalyst, where the catalyst is reduced concurrently with the dehydrogenation by using CO as a reducing gas. In reducing the catalyst with CO, CO.sub.2 is produced, which may be reacted with H.sub.2 produced by the dehydrogenation, to form CO and H.sub.2O by the reverse water-gas shift reaction. A Cu O heat-releasing material may be included with the catalyst in the reactor. The CO reducing gas reduces CuO to form Cu and CO.sub.2, releasing heat. The CO.sub.2 produced by reducing the Cu O may also be reacted with H.sub.2 produced by the dehydrogenation, to form CO and H.sub.2O by the reverse water-gas shift reaction.

A feed injector may have a body having an outer wall and an inner wall with a first conduit formed between the outer wall and the inner wall. The first conduit is configured to receive a atomizing gas. Additionally, a second conduit may be formed by the inner wall, and the second conduit is configured to receive a liquid. The first conduit and the second conduit are separated by the inner wall. Further, a mixing chamber may be provided at an outlet of the first conduit and an outlet of the second conduit. The atomizing gas from the first conduit and the liquid from the second conduit hit and/or mix together in the mixing chamber to form liquid droplets and a mixture of the atomizing gas and the liquid. Furthermore, a flow cone may have a first end in the second conduit and a second end in the mixing chamber.

The present invention relates to a nitro compound hydrogenation reaction process and hydrogenation reaction apparatus, which can achieve the objects of the continuous reaction of the nitro compound and the long-period run of regeneration and activation. The nitro compound hydrogenation reaction process comprises a hydrogenation step, a regeneration step, an optional activation step and a recycling step. There exists at least one step of degassing the spent catalyst between the hydrogenation step and the regeneration step. According to circumstances, there exists at least one step of degassing the regenerated catalyst between the regeneration step and the activation step.

The invention provides a process for regenerating a catalyst used for the hydrogenation of an aromatic species, consisting of several steps. First the system is purged with nitrogen, then air is metered in stepwise, and the addition of nitrogen is subsequently ended until only air is present.

The invention provides a process for regenerating a catalyst used for the hydrogenation of an aromatic species, consisting of several steps. First the system is purged with nitrogen, then air is metered in stepwise, and the addition of nitrogen is subsequently ended until only air is present.

The invention provides a process for regenerating a catalyst used for the ring hydrogenation of an aromatic species, especially an aromatic ester, wherein a gas stream containing a particular amount of oxygen is used for the regeneration.

The invention provides a process for regenerating a catalyst used for the ring hydrogenation of an aromatic species, especially an aromatic ester, wherein a gas stream containing a particular amount of oxygen is used for the regeneration.