A method of operating a polyethylene reactor system includes feeding ethylene, an optional first comonomer, a diluent, and a chromium-based catalyst to a first polymerization reactor. The method further includes contacting ethylene and the comonomer with the catalyst in the first polymerization reactor to form a first product including a first polyethylene. The method further includes feeding the first product from the first polymerization reactor to a second polymerization reactor. The method further includes contacting ethylene and a second optional comonomer with catalyst from the first reactor in the second polymerization reactor to form a second product including the first polyethylene and a second polyethylene. The method further includes controlling one or both of a molecular weight or a breadth of molecular weight distribution of the second product by adjusting a rate of hydrogen fed to one or both of the first polymerization reactor or the second polymerization reactor.

The present invention relates to a method and gasification system for recycling methane-rich gas from syngas stream emanating from fluidized bed reactor and then returning the methane to the fluidized bed reactor. The method comprises recovering methane-rich gas from the synthesis gas and delivering at least a portion of the recovered methane-rich gas to the fluidized bed reactor. Methods to recover methane-rich gas from syngas at different steps in the gasification system are also provided herein.

A method of manufacturing lithium-metal nitride including suspending a lithium-metal-oxide-powder (LMOP) within a gaseous mixture, incrementally heating the suspended LMOP to a holding temperature of between 400 and 800 degrees Celsius such that the LMOP reaches the holding temperature, and maintaining the LMOP at the holding temperature for a time period in order for the gaseous mixture and the LMOP to react to form a lithium-metal nitride powder (LMNP).

A method for the conversion of a carbonaceous material. The method comprising the steps of providing a carbonaceous material, providing a hot powder material and contacting the carbonaceous material and the powder material in an atmosphere configured to no more than partially oxidize carbon to CO.sub.2. The carbonaceous material is at least a partial converted into volatiles. The volatiles are separated from the additional components by specific gravity.

A hydrocarbon feed stream may be processed by a method that may include catalytically cracking a hydrocarbon feed stream in a counter-current reactor to produce a first effluent stream, and processing a portion or all of the first effluent stream by at least one or more separations. The at least one or more separations may form at least a second effluent stream including at least 95 wt. % C.sub.4-C.sub.6 hydrocarbons, and a third effluent stream including at least 95 wt. % of ethane, propane, or a combination thereof. In some embodiments, the method may further include catalytically cracking a portion or all of the second effluent stream in a second reactor to form a second reactor effluent stream, combining a portion of all of the second reactor effluent stream with the first effluent stream, steam cracking a portion or all of the third effluent stream to form a steam cracked effluent stream, and combining a portion or all of the steam cracked effluent stream with the first effluent. In other embodiments, the method may further include passing a portion or all of the second effluent stream to the counter-current reactor, steam cracking a portion or all of the third effluent stream to form a steam cracked effluent stream, and combining a portion or all of the steam cracked effluent stream with the first effluent stream.

Systems and methods useful in determining the superficial gas velocity in fluidized bed reactors may utilize a pressure drop across a portion of the system but not associated with a flowmeter. For example, method may comprise: obtaining a pressure for each of two different locations within a fluidized bed reactor system that comprises a reactor capable of containing a fluidized bed and a cycle gas loop, wherein one or both of the two different locations is not at a flowmeter; calculating a pressure drop based on the two pressures; calculating a first superficial gas velocity (SGV.sub.alt) for the fluidized bed based on the pressure drop; and operating the fluidized bed reactor system based at least in part on the SGV.sub.alt.

An apparatus for controlling flow of a material includes an inlet for receiving the material from a source, and a seal mechanism connected to the inlet, the seal mechanism having a fluidizing bed configured to receive the material from the inlet, a first discharge passageway and a second discharge passageway. The fluidizing bed includes a first transport zone associated with the first discharge passageway and a second transport zone associated with the second discharge passageway, wherein the first and second transport zones are configured to receive transport gas from a transport gas source. The transport gas is controllable to selectively divert a flow of the material into the first discharge passageway and the second discharge passageway.

A multi-stage product gas generation system converts a carbonaceous material, such as municipal solid waste, into a product gas which may subsequently be converted into a liquid fuel or other material. One or more reactors containing bed material may be used to conduct reactions to effect the conversions. Unreacted inert feedstock contaminants present in the carbonaceous material may be separated from bed material using a portion of the product gas. A heat transfer medium collecting heat from a reaction in one stage may be applied as a reactant input in another, earlier stage.

A system for preventing a catalyst from overheating is provided. The system includes: a first reactor filled with a catalyst at least in part and configured to receive reaction gas and produce product gas; and a second reactor configured to cool a catalyst discharged from the first reactor. The catalyst is circulated between the first reactor and the second reactor by injecting the catalyst cooled in the second reactor into the first rector.

Techniques and systems for reducing fouling in a polymerization system are described. The polymerization system includes a reactor coupled to a recycle system. The recycle system includes at least one fouling-susceptible unit. The technique includes inducing polymerization of a reactant, for example, at least one olefin monomer reactant, with a catalyst in the reactor. The technique may further include circulating a fluidizing stream through the reactor and the at least one fouling-susceptible unit. The fluidizing stream may include entrained particles tending to foul the at least one fouling-susceptible unit. The technique can further include contacting the fluidizing stream with a catalyst poison at at least one location upstream of the at least one fouling-susceptible unit in the recycle system.