摘要:
Embodiments of a process and a plant for manufacturing polyethylene and ethylene based copolymers in which a) a compressor unit feed stream (10), comprising ethylene, is fed into a compressor unit (1) for increasing the pressure for a reactor (2) for radical polymerization of the ethylene, b) a compressor unit output stream (11) of more than 1 t/h is fed into the reactor (2), and c) wherein a gas purification unit (5) separates comonomers and / or chain transfer agents from a gaseous stream (15) downstream from the reactor (2), wherein the gas purification unit (5) comprises a high-pressure section for separating ethylene from the comonomers and/or chain transfer agents under supercritical conditions and a low pressure section for removing ethylene from the comonomers and/or chain transfer agents under non-supercritical conditions.
摘要:
Continuous process for preparing a halogenated polymer comprising a step of polymerization of at least one halogenated monomer in a medium comprising carbon dioxide in the liquid or supercritical state, in at least one pressurized reactor, said process comprising at least : - (1) an expansion of the suspension resulting from the reactor; - (2) a separation of the expanded suspension resulting from the reactor into a first stream, containing the solid phase comprising the halogenated polymer and into a liquid, gaseous or supercritical second stream, which is a mixture Of CO 2 and of monomer not converted to polymer; and the recovery of this first stream and of this second stream; the expansion (1) of the suspension resulting from the reactor and its separation (2) into first and second streams are carried out in several steps at successively decreasing pressures. - (3) an optional reheating, applied to the expanded suspension, before or after its separation into first and second streams, with optional recovery of the cold energy generated by the expansion; - (4) a recompression of the second stream, and the optional cooling thereof, in order to recycle it to the reactor feed, with a fresh monomer make-up and, possibly, a CO 2 make-up; - (5) a final step of degassing the halogenated polymer, optionally in combination with a continuous technique of forming the polymer into granules. Device for implementing the process.
摘要:
A process for heating a polymer-containing stream being transferred from a polymerization reactor to a separation zone or device, comprising passing the stream through at least two heaters operating in parallel, each heater comprising at least one transfer line for the stream and means for heating the transfer line, wherein the temperature of the polymer-containing stream at the outlet of all heaters is maintained above the dew point of the stream, and no heater has a volumetric fiowrate of polymer-containing stream more than three times that of any other heater.
摘要:
Beschrieben wird ein Verfahren zum Regenerieren der Sauerstoff-Permeationsfähigkeit einer Membran enthaltend eine Sauerstoffanionen leitende Keramik. In dem Verfahren wird die Membran nach einer Betriebsphase mindestens einer Regenerationsphase unterworfen, in welcher die Temperatur der Membran so weit über die in der Betriebsphase gewählte Temperatur erhöht wird, dass die Sauerstoff-Permeationsfähigkeit der Membran sich wieder erhöht. Das Verfahren kann beim Abtrennen von Sauerstoff aus Gasen oder zur Durchführung von Oxidationsreaktionen in einem Membranreaktor eingesetzt werden und erlaubt den Betrieb dieser Vorrichtungen bei Temperaturen unterhalb von 800°C. Die eingesetzten Reaktoren weisen mindestens eine Vorrichtung auf, welche das Erhitzen der Membran durch direkten oder indirekten Wärmetausch gestattet.
摘要:
Process for the preparation of urea from ammonia and carbon dioxide in a urea production process comprising, in a high-pressure synthesis section, a. a reactor, wherein ammonia and carbon dioxide react to form a urea-comprising synthesis solution, b. a stripper, wherein the urea-comprising synthesis solution is heated and stripped, optionally in counter-current with a stripping agent, c. a submerged condenser, wherein the gas leaving the top of the stripper is, at least partially, condensed to form a condensate solution and d. an ejector, in the line connecting the submerged condenser and the reactor, supporting the transport of the condensate solution from the submerged condenser to the reactor, wherein a gas stream leaving the top of the submerged condenser is controlled by one or more controlling elements.
摘要:
The invention provides a process and an apparatus for the high pressure polymerization of ethylene in which a jet pump is used to pump a fluid into a polymer/monomer product mixture leaving a bumped tubular reactor. The fluid may be recycled monomer or another fluid such as a modifier.
摘要:
A process for the condensation of sulfur trioxide from hot starting gases comprising the following steps: a) cooling the starting gas to a temperature of 40 to 45O0C in at least one heat exchanger (3) (4), in which a gas is used as cooling medium, b) introducing the cooled starting gas into a condensation device (5), c) condensing the sulfur trioxide in the condensation device (5), in which a liquid chemically inert to sulfur trioxide is used as cooling medium, and d) withdrawing the condensed, liquid sulfur trioxide from the condensation device (5). A plant for carrying out the process comprising: a first and a second heat exchanger (3) (4) comprising supply and discharge conduits for coolant and starting gas, and a condensation device (5), in which a liquid chemically inert to sulfur trioxide is provided as cooling medium.