A process for producing paraxylene by the catalytic alkylation of benzene and/or toluene with methanol, which produces a para-rich mixture of xylene isomers, together with water and some light organic by-products, particularly dimethyl ether and C.sub.4 olefins. The off-gas stream, containing the C.sub.4 olefins, may be recycled back to the reaction to be co-injected with methanol to reduce the methanol self-decomposition and the reaction of methanol to olefins or to fluidize catalyst particles recovered by a reactor cyclone. By using recycled off-gas rather than water or steam, the deleterious effects of water and/or steam on the catalyst aging and activity rates and the size of downstream equipment necessary to recover olefin by-products may be reduced.

A polyolefin production system is provided. The polyolefin production system includes a plurality of gas-phase polymerization tanks configured to polymerize an olefin gas to form a polyolefin, a compressor comprising an inlet and an outlet and being configured to compress a an olefin-containing gas, an individual gas feed line disposed at each of the gas-phase polymerization tanks and configured to guide the gas fed from the outlet of the compressor to each of the gas-phase polymerization tanks, an individual gas discharge line disposed at each of the gas-phase polymerization tanks and discharging the gas from each of the gas-phase polymerization tanks, and a first valve installed in each of the individual gas feed lines.

A device for the intimate mixing of solid particles and a gaseous medium within a gas-solid fluidized bed, comprising a plurality corrugated and/or ribbed planar stanchions arranged in alternating intersecting planes that provide a plurality of open spaces between or adjacent the alternating intersecting planar stanchions. The element has a three-dimensional lattice configuration and the corrugated and/or ribbed planar stanchions are formed from metal having peaks and valleys or ribs, such that the peaks and valleys or ribs are angled at less than 90 degrees from the fall-line of the planar stanchion when assembled into the element. The angled peaks and valleys or ribs form channels that enhance lateral movement of catalyst particles into the spaces between the stanchions to provide improved vapor/solids mixing and contact.

The present disclosure provides a separator system for performing separation and dehydroxylation of fumed silica particles. The separator system includes a first inlet, a second inlet, a main body, a first outlet and a second outlet. The first inlet collects a primary feed of fumed silica particles from a gaseous stream into a double entry cyclone. The second inlet collects a secondary feed of chlorine gas into the double entry cyclone. The main body of the double entry cyclone is utilized in treating the primary feed and the secondary feed along with heat inside the double entry cyclone. Furthermore, the first outlet is utilized for releasing the dehydrated fumed silica particles and the second outlet is utilized for releasing the water molecules and other gases.

This disclosure provides a reactor system that includes a microwave energy source that generates a microwave energy, a field-enhancing waveguide (FEWG) coupled to the microwave source. The FEWG includes a field-enhancing zone having a cross-sectional area that decreases along a length of the FEWG. The field-enhancing zone includes a supply gas inlet that receives a supply gas, a reaction zone that generates a plasma in response to excitation of the supply gas by the microwave energy, a process inlet that injects a raw material into the reaction zone, and a constricted region that retains a portion of the plasma and combines the plasma and the raw material in response to the microwave energy within the reaction zone. An expansion chamber is in fluid communication with the constricted region facilitates expansion of the plasma. An outlet outputs a plurality of carbon-inclusive particles derived from the expanded plasma and the raw material.

Apparatuses and processes that produce multimodal polyolefins, and in particular, polyethylene resins, are disclosed herein. This is accomplished by using two reactors in series, where one of the reactors is a multi-zone circulating reactor that can circulate polyolefin particles through two polymerization zones optionally having two different flow regimes so that the final multimodal polyolefin has improved product properties and improved product homogeneity.

Apparatuses and processes that produce multimodal polyolefins, and in particular, polyethylene resins, are disclosed herein. This is accomplished by using two reactors in series, where one of the reactors is a multi-zone circulating reactor that can circulate polyolefin particles through two polymerization zones optionally having two different flow regimes so that the final multimodal polyolefin has improved product properties and improved product homogeneity.

A system for processing a hydrocarbon feed has a final stage reactor and internal separator with cyclone that forms a substantially gas stream and a substantially non-gas stream. The substantially gas stream is sent directly from the final stage reactor and separator to further downstream processing.

A system for processing a hydrocarbon feed has a final stage reactor and internal separator that forms a substantially gas stream and a substantially non-gas stream. The substantially gas stream is sent directly from the final stage reactor to a separator or for other processing.

A method for processing a chemical stream includes contacting a feed stream with a catalyst in an upstream reactor section of a reactor having the upstream reactor section and a downstream reactor section, passing an intermediate product stream to the downstream reactor section, and introducing a riser quench fluid into the downstream reactor section, upstream reactor section, or transition section and into contact with the intermediate product stream and the catalyst to slow or stop the reaction. The method includes separating at least a portion of the catalyst from the product stream, passing the product stream to a product processing section, cooling the product stream, and separating a portion of the riser quench fluid from the product stream. The riser quench fluid separated from the product stream may be recycled back to the downstream reactor section, upstream reactor section, or transition section as the riser quench fluid.