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).

The present disclosure relates to chemical synthesis. The teachings thereof may be embodied in methods for chemical synthesis and/or reactors for synthesis. The teaching may increase the conversion of equilibrium-limited reactions in a single pass through a synthesis reactor. For example, a method may include: introducing a synthesis reactant into a reaction chamber with a prevailing pressure p1; forming a synthesis product; discharging the product and any unreacted reactant; separating the product from the unreacted reactant; and introducing the unreacted reactant into a second reaction chamber with a prevailing pressure p2 lower than the pressure p1.

In a novel process for methanol production from low quality synthesis gas, in which relatively smaller adiabatic reactors can be operated more efficiently, some of the inherent disadvantages of adiabatic reactors for methanol production are avoided. This is done by controlling the outlet temperature in the pre-converter by rapid adjustment of the recycle gas, i.e. by manipulating the gas hourly space velocity in the pre-converter.

A process comprising polymerizing olefin monomers and optionally comonomers in a first reactor vessel, thereby forming a raw product stream comprising polymerized solids, unreacted monomer and optionally comonomer, the polymerized solids comprising olefin polymer, volatile organic compounds (VOC) and catalyst system. Then the polymerized solids are contacted with a catalyst poison selected from carbon monoxide, carbon dioxide, oxygen, water, alcohols, amines, or mixtures thereof, thereby forming a passivated stream. The passivated stream is maintained in an agitated state within a second reactor. The passivated stream within the second reactor is then contacted with a circulating gas comprising unreacted monomer for a residence time, thereby reducing the concentration of VOC in the polymerized solids by at least 10 wt % compared to the level before entering the second reactor, thereby forming a purified olefin polymer solids stream.

A process layout for large scale methanol synthesis comprises one or more boiling water reactors and one or more radial flow reactors in series, the boiling water reactor(s) being fed with approximately fresh make-up syngas. The methanol synthesis loop comprises a make-up gas compressor K1, a recycle gas compressor K2, two or more boiling water converters for methanol synthesis (A1, A2, . . . ), a radial flow converter (B) for methanol synthesis, a steam drum (V1), a high pressure separator (V2), a low pressure separator (V3), feed effluent heat exchangers (E1 and E2), a wash column (C), an air cooler (E3) and a water cooler (E4).

Process for the preparation of a polyolefin in a reaction system comprising a reactor comprising a fluidized bed and a distribution plate, product purge bin, and granular feed bin, wherein the process comprises feeding a polymerization catalyst to the fluidized bed, feeding -olefin monomer(s) to the reactor, circulating fluids from the top of the reactor to the bottom of the reactor, withdrawing a stream comprising the polyolefin and fluids from the reactor and passing said stream into the product purge bin, purging the product purge bin with a purge stream comprising an inert gas to obtain a stream comprising a purged polyolefin and a stream comprising fluids, introducing part of the stream comprising fluids back into the reactor, introducing the stream comprising the purged polyolefin into the granular feed bin, and contacting a deactivating stream with purged polyolefin in granular feed bin to obtain the polyolefin free of polymerization catalyst.

Methods for producing polyolefin polymers may use a predictive melt index regression to estimate the melt index of the polyolefin during production based on the composition of the gas phase and, optionally, the concentration of catalyst in the reactor or reactor operating conditions. Such predictive melt index regression may include multiple terms to account for concentration of ICA in the reactor, optionally concentration of hydrogen in the reactor, optionally concentration of comonomer in the reactor, optionally the catalyst composition, and optionally reactor operating conditions. One or more terms may independently be represented by a smoothing function that incorporates a time constant.

The invention concerns a process and apparatus for cracking ammonia in which heated ammonia gas at super-atmospheric pressure is partially cracked catalytically in an adiabatic reaction unit to produce partially cracked ammonia gas which is heated and fed to catalyst-containing reactor tubes in a furnace to cause cracking of further ammonia and produce a cracked gas comprising hydrogen gas, nitrogen gas and residual ammonia gas. At least some, preferably all, of the duty required to heat the partially cracked ammonia gas is provided by heat exchange with the cracked gas, enabling more efficient heat integration within the process.

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.

The present invention concerns a process for cracking ammonia comprising providing an ammonia-containing feed gas at a temperature of over 600? C. and a pressure in a range from about 5 bar to about 50 bar; combusting a fuel with an oxidant gas in a furnace to heat reactor tubes to achieve a maximum inner wall temperature of over 700? C. and produce a flue gas, each reactor tube comprising a catalyst bed comprising a first row transition metal-based catalyst; and feeding the ammonia-containing feed gas to the reactor tubes to produce a cracked gas at a temperature of over 600? C. on exit from the reactor tubes.