摘要:
In a method of modernizing a heterogeneous exothermic synthesis reactor (1) of the type comprising an external shell (2), in which at least one catalytic bed (15, 16, 17) is supported, the catalytic bed (15, 16, 17) is connected to an external boiler (21), for generating high pressure steam, by means of a reacted gas outlet nozzle (4) and a conduit (29) extending in said nozzle (4) thereby forming an annular airspace (30). Advantageously, the airspace (30) defines an outlet flowpath of the gases cooled in the boiler (21) which avoids overheating of the nozzle (4).
摘要:
A method for "in-situ" modernization of a reactor for effecting heterogeneous exothermic synthesis reactions, especially of the so-called Kellogg type, including the preliminary step of providing at least three radial or axial-radial catalyst beds (11, 12, 13), includes the steps of providing a first gas/gas heat exchanger (18) between the first (11) and second (12) catalyst beds and a second gas-gas heat exchanger (29) in the third catalyst bed (13). Thanks to the provision of two exchangers (18, 29) for cooling of the gases flowing between the catalyst beds by means of indirect heat exchange, the present modernization method allows to achieve a reactor with a high conversion yield.
摘要:
A Method for in-situ modernization of a heterogeneous exothermic synthesis reactor, comprising the steps of providing at least a first and at least a second catalytic bed (12, 13) in an upper (2a) respectively lower (2b) portion of the reactor, providing additionally a lowermost catalytic bed (14) in the lower portion (2b) of the reactor having a reaction volume smaller than the reaction volume of the second catalytic bed (13), and loading the lowermost catalytic bed (14) with a catalyst having an activity higher that the activity of the catalyst loaded in the other beds (12, 13). Thanks to the above steps, the present method allows to obtain a reactor with high conversion yield.
摘要:
A tube isothermal chemical reactor (1), comprising a vessel (2) with a central axis (A-A), and an annular tube heat exchanger (40) embedded in a catalytic reaction space, the exchanger (40) comprising a plurality of concentric ranks (10, 11) of tube packs (10a), each of said tube packs comprising parallel tubes (30), a respective heat-exchange fluid feeder (20) and a respective heat-exchange fluid collector (21).
摘要:
A process for ammonia -urea production where: liquid ammonia produced in an ammonia section is fed to a urea section directly at the ammonia synthesis pressure, and where the liquid ammonia is purified at high pressure with the steps of: cooling the liquid ammonia (20) obtaining a cooled liquid ammonia stream (21), separating a gaseous fraction (22) comprising hydrogen and nitrogen from said cooled liquid ammonia, obtaining purified liquid ammonia (23) at a high pressure, and reheating said purified liquid ammonia (23) after separation of said gaseous fraction, obtaining a reheated purified ammonia (24) having a temperature suitable for feeding to the urea synthesis process. The application also deals with an ammonia -urea plant comprising an ammonia cooler, a liquid-gas separator and an ammonia re-heater and with a method for revamping existing ammonia -urea plants.
摘要:
Method and apparatus for carrying out highly exothermic catalyzed reactions, like so-called oxidative reactions, in pseudo-isothermal conditions, for example the reaction for producing nitric acid and the reaction for producing formaldehyde.
摘要:
Isothermal vertical reactor (1) for a chemical reaction, comprising a shell (2) with internal gas-permeable walls (16, 18) defining an inlet distribution chamber (17) and a product collecting chamber (19), an open-top catalytic bed between said gas-permeable walls, and a tube heat exchanger (5) embedded in said catalytic bed, the tube heat exchanger (5) comprising a bundle of U-tubes, where an inlet (14) is disposed to direct a fresh charge in an upper chamber (21) over the catalytic bed and the U-shaped top portion of the tube bundle; a portion (F1) of the fresh charge passes through the catalytic bed with a mixed axial-transversal flow, and another portion (F2) of the fresh charge enters the inlet gas-distribution chamber (17) and passes through the catalytic bed with a substantially transversal flow.
摘要:
Plate type heat exchanger (20,120) for a isothermal chemical reactor (60), of the type comprising a substantially box-shaped flattened body (22), defining an internal chamber (24) and equipped with an inlet connection (28) and an outlet connection (29) for a first flow of a heat exchanger operative fluid into and from said chamber (24), at least one supplying-distributing device (26, 126) of a second fluid flow, associated with said body (22) and in fluid communication with the internal chamber (24) thereof, in order to regulate the temperature of said operative fluid, said at least one supplying-distributing device (26,126) being supported inside said internal chamber (24) and in fluid communication therewith.
摘要:
A process for producing ammonia synthesis gas, where a natural gas feedstock (10) is reformed in a primary steam reformer (12) and in a secondary reformer (14) at a pressure of at least 35 bar; the product syngas (16) at the output of the secondary reformer is cooled and subject to catalytic medium-temperature shift, converting the CO into CO2 and H2; downstream said medium-temperature shift, the carbon dioxide is removed from the syngas by physical absorption.
摘要:
An internal start-up heater (10) for an ammonia reactor (1), comprising longitudinal heating members (16) and a supporting structure for said heating members (16), the structure comprising plates (20A-20D) with parallel beams (22A-22D) in contact with said heating members (16), wherein the plates are arranged in plate sets formed by at least a first and a second plate having differently arranged supporting beams.