Abstract: A process for producing ammonia make-up synthesis gas and a procedure for revamping a front-end of an ammonia plant for producing ammonia make-up synthesis gas are disclosed, wherein the make-up synthesis gas is produced by means of steam reforming of a hydrocarbon gaseous feedstock; said front-end includes a primary reformer, a secondary reformer, a shift conversion section, a CO2 removal section and optionally a methanation section; a shell-and-tube gas-heated reformer is installed after said secondary reformer, and a portion of the available feedstock is reformed in the tubes of said gas-heated reformer, and heat is provided to the shell side of said gas-heated reformer by at least a portion of product gas leaving the secondary reformer, possibly mixed with product gas leaving the tubes of said gas-heated reformer.

Abstract: A method for recovering waste heat in a process for the synthesis of a chemical product, particularly ammonia, where the product is used as the working fluid of a thermodynamic cycle; the waste heat is used to increase the enthalpy content of a high-pressure liquid stream of said product (11), delivered by a synthesis section (10), thus obtaining a vapour or supercritical product stream (20), and energy is recovered by expanding said vapour or supercritical stream across at least one suitable ex-pander (13); the method is particularly suited to recover the heat content of the syngas effluent after low-temperature shift.

Abstract: A method for the control of nitrogen oxides content in the combustion fumes of a thermal power plant is disclosed; the method comprises the on-site production of ammonia by the steps of: electrolysis of water as a source of hydrogen; separation of air as a source of nitrogen, formation of a make-up gas and synthesis of ammonia in a suitable synthesis loop; said on-site produced ammonia, or a solution thereof, is used for a process of reduction of nitrogen oxides in the combustion fumes.

Abstract: A process for producing a synthesis gas containing hydrogen and nitrogen, suitable for production of ammonia, wherein a raw synthesis gas (13) obtained by reforming of a natural gas feedstock is purified in a cryogenic separator (CS), and a portion of purified gas (16) is expanded and used as a cooling medium in the same separator, said expanded portion (16) being then re-introduced in the main stream of purified synthesis gas. A suitable apparatus and revamping of conventional plants according to the invention are also disclosed.

Abstract: 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.

Abstract: A method for the control of nitrogen oxides content in the combustion fumes of a thermal power plant is disclosed; the method comprises the on-site production of ammonia by the steps of: electrolysis of water as a source of hydrogen; separation of air as a source of nitrogen, formation of a make-up gas and synthesis of ammonia in a suitable synthesis loop; said on-site produced ammonia, or a solution thereof, is used for a process of reduction of nitrogen oxides in the combustion fumes.

Abstract: A method for regulation of an ammonia plant where a purge gas (10) containing inerts is extracted from ammonia synthesis loop (SL), and where the ammonia plant is operated at a partial load by keeping the ammonia synthesis loop at a nominal high pressure, and reducing the purge rate in order to increase concentration of inerts in the ammonia synthesis loop and avoid overheating of the ammonia reactor; preferably a water electrolysis section (WE) produces a hydrogen feed (3) and an air separator produces a nitrogen feed (4); hydrogen and nitrogen are mixed to form a make up gas (5) which is reacted at a high-pressure in said ammonia synthesis loop (SL).

Abstract: A process for producing ammonia synthesis gas from a hydrocarbon-containing feedstock, with steps of primary reforming, secondary reforming with an oxidant stream, and further treatment of the synthesis gas including shift, removal of carbon dioxide and methanation, wherein the synthesis gas delivered by secondary reforming is subject to a medium-temperature shift (MTS) at a temperature between 200 and 350° C., and primary reforming is operated with a steam-to-carbon ratio lower than 2. A corresponding method for revamping an ammonia plant is disclosed, where an existing HTS reactor is modified to operate at medium temperature, or replaced with a new MTS reactor, and the steam-to-carbon ratio in the primary reformer is lowered to a value in the range 1-5-2, thus reducing inert steam in the flow rate trough the equipments of the front-end.

Abstract: A process for selective removal of a gaseous product (P) from a gaseous system comprising said product and other components (R1, R2), wherein the gaseous system is admitted to a first environment, which is separated from a second environment by a boundary wall, and a permeation membrane (3, 300) forms at least part of said boundary wall; a spatially non-uniform electric field (4) is generated between a first electrode or first plurality of electrodes (1, 301) located in the first environment and a second electrode or second plurality of electrodes (2, 302) located in the second environment, so that field lines of said non-uniform electric field cross said membrane, and a dielectrophoretic force generated on particles of said gaseous component (P) is at least part of a driving force of the permeation through said membrane, an amount of said product (P) being selectively removed from the first environment and collected in the second environment.

Abstract: An ammonia plant is disclosed, where ammonia purge gas (20), is sent to a cryogenic recovery unit, said recovery unit comprising means of cooling (102, 202, 302, 402, 502) and a high-pressure phase separator (103, 203, 303, 403, 503) operating at loop pressure; inside said unit the purge gas (20) is cooled to a cryogenic temperature, and a partial liquefaction of methane and argon is achieved; the high-pressure phase separator separates the cooled stream into a gaseous stream and a bottom liquid; the gaseous stream is reheated in a passage of a heat exchanger; the unit is then capable to export a gaseous stream (123, 223, 323, 423, 523) containing nitrogen and hydrogen at loop pressure, that can be reintroduced at the suction side of the circulator (4) of the loop.

Abstract: Method for modifying a hot wall ammonia reactor con vessel (2) having partial opening, comprising: assembly directly inside the vessel (2) of a catalytic cartridge (7) with modular elements, said modular elements being of a size compatible with introduction into the vessel through a pre-existing partial opening (6) of the vessel, and each comprising at least one panel (11); the panels (11) of said modular elements forming a substantially cylindrical outer wall (7a) of said cartridge (7), and an annular flux space (8) between said outer wall of the cartridge and an inner wall of the vessel; said panels (11) being provided with a respective heat insulation layer (13) before introduction into the vessel (2).

Abstract: A method for modernizing an ammonia synthesis loop (1) with a first converter (10) and a second converter (11) in series, the first converter (10) comprises a cartridge with one or more catalyst beds, the second converter (11) comprises a catalyst bed in direct contact with said vessel, the method comprising the steps of removing the second converter, and boosting the first converter by replacing the cartridge with a high-efficiency cartridge comprising a plurality of adiabatic catalyst beds and inter-bed heat exchangers, or an isothermal catalyst bed, and by reducing the concentration of inerts in said first converter.

Abstract: A process and related equipment for producing ammonia synthesis gas are disclosed, wherein a raw syngas (13) is purified in a cryogenic section (CS) and a nitrogen-rich liquid stream (30) is separated from the raw syngas flow during purification and HN ratio adjustment, and wherein the pressure of said liquid stream (30) is reduced in a turbine (60) to enhance net refrigerative effect for the cryogenic section. Embodiments wherein chilling is also provided by a low-pressure or high-pressure syngas expander are also disclosed.

Abstract: A process for the synthesis of ammonia, where: a front-end produces a make-up syngas (10) having a substantial excess of nitrogen, the H2/N2 ratio being less than 3; hydrogen is separated from a purge stream (15) taken in the high-pressure synthesis loop, with a molecular sieve or a cryogenic device, obtaining a hydrogen-rich gaseous stream (16); said hydrogen-rich gaseous stream (16) is returned to the ammonia synthesis loop, thus obtaining that the H2/N2 ratio of the gas feed (12) actually converted into ammonia is close to 3 and preferably in the range 2.9-3.1.

Abstract: A process and a related equipment for making ammonia make-up synthesis gas are disclosed, where: a hydrocarbon feedstock is reformed obtaining a raw ammonia make-up syngas stream; said raw syngas is purified in a cryogenic purification section refrigerated by a nitrogen-rich stream produced in an air separation unit; the nitrogen-rich stream at output of said cryogenic section is further used for adjusting the hydrogen/nitrogen ratio of the purified make-up syngas; an oxygen-rich stream is also produced in said air separation unit and is fed to the reforming section.

Abstract: A method for recovering waste heat in a process for the synthesis of a chemical product, particularly ammonia, where the product is used as the working fluid of a thermodynamic cycle; the waste heat is used to increase the enthalpy content of a high-pressure liquid stream of said product (11), delivered by a synthesis section (10), thus obtaining a vapour or supercritical product stream (20), and energy is recovered by expanding said vapour or supercritical stream across at least one suitable ex-pander (13); the method is particularly suited to recover the heat content of the syngas effluent after low-temperature shift.

Abstract: A process for effecting mass transfer between liquid phase and a gaseous phase in a filled-type column having an external shell which accommodates at least one filler-containing basket wherethrough the phases are caused to flow in countercurrent relationship. The process advantageously includes the step of feeding the gaseous phase to the at least one basket through a gas-permeable surface thereof which is larger than the basket cross-section, preferably in a prevailing radial flow direction.

Abstract: A process for the production of synthesis gas for obtaining compounds such as ammonia or methanol, in which hydrocarbons and steam are reacted first in a primary reforming section (11) and then—together with oxygen—in a secondary reforming section (12), thus obtaining CO, CO2, H2 and possibly N2 which are then fed to a carbon monoxide conversion section (13, 14), is distinguished by the fact of reacting hydrocarbons, steam and oxygen in an autothermal reforming section (20) provided in parallel with respect to other reforming sections (11, 12), and feeding the so produced CO, CO2, H2 and possibly N2 to the carbon monoxide conversion section (13, 14).

Abstract: The system to reduce the energy consumption of heterogeneous synthesis reactors, particularly of ammonia reactors, f.i. the "Chemico"-type reactor, foresees the insertion of two cylindrical walls at least partially perforated in order to annularly delimit the catalytic beds; the first outer wall (Fe) having a diameter (Di) slightly smaller than diameter (Dc) of the cartridge (C), has a height (Hi) higher than (H'i) of the internal cylindrical wall (Fi) which has a diameter inferior to the above mentioned (Di), but superior to the external diameter (Dt) of the central feed pipe (T) of the quench gas (QG). The top (SO) of the internal cylindrical wall (Fi) is closed by a cover (CO) that has a distance from the bottom (FO) of the basket equal to the mentioned height (H'i) of the internal cylindrical wall. The catalytic bed is therefore annular in diameter (Di-D'i) on all of the said height (H'i), but is substantially cylindrical (of diameter Di) on the height (Hi-H'i).