The present disclosure provides oxidative coupling of methane (OCM) systems for small scale and world scale production of olefins. An OCM system may comprise an OCM subsystem that generates a product stream comprising C.sub.2+ compounds and non-C.sub.2+ impurities from methane and an oxidizing agent. At least one separations subsystem downstream of, and fluidically coupled to, the OCM subsystem can be used to separate the non-C.sub.2+ impurities from the C.sub.2+ compounds. A methanation subsystem downstream and fluidically coupled to the OCM subsystem can be used to react H.sub.2 with CO and/or CO.sub.2 in the non-C.sub.2+ impurities to generate methane, which can be recycled to the OCM subsystem. The OCM system can be integrated in a non-OCM system, such as a natural gas liquids system or an existing ethylene cracker.

A method and system for formation of a polyarylene sulfide is described. The method includes a first stage in which a complex is formed in a reactor. The complex includes the hydrolysis product of an organic amide solvent and an alkali metal hydrosulfide. The complex formation reaction also forms hydrogen sulfide as a by-product. The method also includes treating a fluid stream that is pulled off of the reactor. The treatment includes scrubbing the fluid stream to recover hydrogen sulfide from the stream and return the hydrogen sulfide to the reactor. The recovery and recycle of the hydrogen sulfide can prevent loss of sulfur from a polyarylene sulfide formation process.

A process includes periodically or continuously introducing an olefin monomer and periodically or continuously introducing a catalyst system or catalyst system components into a reaction mixture within a reaction system, oligomerizing the olefin monomer within the reaction mixture to form an oligomer product, and periodically or continuously discharging a reaction system effluent comprising the oligomer product from the reaction system. The reaction system includes a total reaction mixture volume and a heat exchanged portion of the reaction system comprising a heat exchanged reaction mixture volume and a total heat exchanged surface area providing indirect contact between the reaction mixture and a heat exchange medium. A ratio of the total heat exchanged surface area to the total reaction mixture volume within the reaction system is in a range from 0.75 in.sup.1 to 5 in.sup.1, and an oligomer product discharge rate from the reaction system is between 1.0 (lb)(hr.sup.1)(gal.sup.1) to 6.0 (lb)(hr.sup.1)(gal.sup.1).

A reservoir for one or more chemical reactants has means for heating the reactants and optional means for stirring the reactants. A pumped reactant feed line and a return line provide fluid communication between the reservoir and a 4-way valve system. The 4-way valve system is also in fluid communication with a reactor vessel and a source of inert gas for purging the system. In a first state, the 4-way valve provides fluid communication between the reservoir and the reactor. In a second state, the 4-way valve provides a continuous circulation path for the heated reactants from the reservoir, to the valve system, and back to the reservoir via the return line. In a third state, the 4-way valve provides a fluid pathway for purging the reactor with inert gas. In a fourth state, the 4-way valve provides a fluid pathway for purging the reservoir with inert gas.

A multi-stage process and system for formation of a polyarylene sulfide is described. The multi-stage process can include at least three separate formation stages that can take place in three different reactors. The first stage of the formation process can include reaction of an alkali metal sulfide with an organic amide solvent to form a complex including a hydrolysis product of the solvent and an alkali metal hydrogen sulfide. The second stage of the formation process can include reaction of the complex formed in the first stage with a dihaloaromatic monomer to form a prepolymer, and the third stage can include further polymerization of the prepolymer with additional monomers to form the final product.

Embodiments disclosed herein relate to the production of polypropylene. At least one olefin monomer stream (10, 12) is fed to a polymerization zone (2). A recirculation gas stream (31) is withdrawn therefrom, compressed into a compressor (4), cooled in a first heat exchanger (5), separated in a phase separator (6), flashed in a pressure regulator (7), fed to a second heat exchanger (8), and recycled (83) to the polymerization zone (2).

The present disclosure provides oxidative coupling of methane (OCM) systems for small scale and world scale production of olefins. An OCM system may comprise an OCM subsystem that generates a product stream comprising C.sub.2+ compounds and non-C.sub.2+ impurities from methane and an oxidizing agent. At least one separations subsystem downstream of, and fluidically coupled to, the OCM subsystem can be used to separate the non-C.sub.2+ impurities from the C.sub.2+ compounds. A methanation subsystem downstream and fluidically coupled to the OCM subsystem can be used to react H.sub.2 with CO and/or CO.sub.2 in the non-C.sub.2+ impurities to generate methane, which can be recycled to the OCM subsystem. The OCM system can be integrated in a non-OCM system, such as a natural gas liquids system or an existing ethylene cracker.

A method for enabling gas exchange and chemical reactions with one or more liquid streams contained in a reactive process vessel are provided. One or more exchange layers within the process vessel can be composed of both collector media and releaser media. The exchange layers allow elements to facilitate increased performance of vessel operations by promoting gas component mixing and diffusion. Improved rates of gas component exchange mean less coking and more gas components available for reaction.

The invention concerns a process and apparatus for cracking ammonia in which heated ammonia gas at super-atmospheric pressure is partially cracked in at least two adiabatic reactors in series with interstage heating in which the feed temperature to a first reactor is higher than the feed temperature to a further reactor to produce a partially cracked ammonia gas which is then fed to catalyst-containing reactor tubes in a furnace to produce a cracked gas comprising hydrogen gas, nitrogen gas and residual ammonia gas. The use of the adiabatic reactors enables more efficient heat integration within the process and the higher temperature in the first reactor enables the use of a nickel-based catalyst in that reactor as an alternative solution to the potential problem of the presence of oil in the ammonia.

A method for enabling gas exchange and chemical reactions with one or more liquid streams contained in a reactive process vessel are provided. One or more exchange layers within the process vessel can be composed of both collector media and releaser media. The exchange layers allow elements to facilitate increased performance of vessel operations by promoting gas component mixing and diffusion. Improved rates of gas component exchange mean less coking and more gas components available for reaction.