Abstract: An integrated process for the synthesis of urea and melamine, wherein urea synthesized in a urea plant is used to produce melamine in a melamine plant connected to the urea plant, according to a high-pressure non-catalytic melamine synthesis process, wherein melamine is synthesized at a pressure higher than urea synthesis pressure and offgas liberated during the synthesis of melamine are returned, as a gas, to the high-pressure synthesis section of the urea plant.

Abstract: A method for determining at least one composition parameter of a urea-synthesis process stream comprising the step of measuring the density of said stream by means of a vibration density meter in contact with said stream and determining the ammonia/carbon dioxide molar ratio N/C of said stream on the basis of the density measured by said vibration density meter.

Abstract: A method for the suppression of soot formation during the partial oxidation of a hydrocarbon-containing gaseous feed, in the presence of steam and in an ATR reactor or in a POX reactor, the method comprising the addition of gaseous carbon dioxide to the hydrocarbon-containing gaseous feed before entry into the reactor. A method for determining a minimum steam to carbon ratio required for scot-free operation is also disclosed.

Abstract: A process for the synthesis of melamine including the purification of the offgas released by the synthesis of melamine by means of a single purification stage (6); in the purification stage (6), the offgas (3) is washed with fresh urea melt and with a recirculated urea melt (8) containing ammonia and melamine precursors (5); said recirculated urea melt is withdrawn from bottom of the single purification stage (6) and cooled in a shell and tube heat exchanger (11), optionally after mixing with the fresh urea melt (15), to a temperature of at least 165° C. preferably in the range 165° C. to 245° C. prior to reintroduction in the purification stage.

Abstract: A process for removing biuret for solid urea (UR), wherein the solid urea is in a granular or powder form, the process including leaching the solid urea with a leaching solution (LS) which is a urea saturated aqueous solution, wherein biuret contained in the solid urea is transferred to said leaching solution during the leaching process, obtaining a purified solid urea.

Abstract: A process for the catalytic oxidation of ammonia, comprising: passing an ammonia-containing gas, in the presence of oxygen, over a catalyst contained in a reactor, obtaining a process gas containing nitrogen oxides, and cooling said process gas with a heat exchanger accommodated in the reactor, wherein a portion of said process gas, located in the shell side, bypasses the heat exchanger and forms a hot current which mixes with cooled gas downstream the heat exchanger, and the bypass is regulated on the basis of a target outlet temperature of the mixed process gas.

Abstract: A process for purifying a urea-containing aqueous stream, such as the aqueous stream from the recovery section of a urea plant, comprising a step of removing biuret from the urea-containing stream by reverse osmosis in one or more reverse osmosis stages.

Abstract: Method for producing solid urea by granulation, wherein the granulation is fed with liquid urea having a purity greater than 98% by weight and not containing formaldehyde.

Abstract: A process for the synthesis of melamine including the purification of the offgas released by the synthesis of melamine by means of a first purification stage followed by a second purification stage (7); in the first purification stage (6) the offgas (3) is contacted with urea melt from the second stage (7) and with a recirculated urea melt (8, 9) containing ammonia and melamine precursors (5); in the second purification stage (7) the offgas from the first stage is contacted with fresh urea melt (15); said recirculated urea melt is withdrawn from bottom of the first stage and cooled in a shell and tube heat exchanger (11) to a temperature of not less than 165° C. preferably in the range 165° C. to 245° C. prior to reintroduction in said first stage.

Abstract: A process for the synthesis of melamine including the purification of the offgas released by the synthesis of melamine by means of a first purification stage followed by a second purification stage (7); in the first purification stage (6) the offgas (3) is contacted with urea melt from the second stage (7) and with a recirculated urea melt (8, 9) containing ammonia and melamine precursors (5); in the second purification stage (7) the offgas from the first stage is contacted with fresh urea melt (15); said recirculated urea melt is withdrawn from bottom of the first stage and cooled in a shell and tube heat exchanger (11) to a temperature of not less than 165° C. preferably in the range 165° C. to 245° C. prior to reintroduction in said first stage.

Abstract: A process for the high-pressure non-catalytic synthesis of melamine from urea wherein various heat inputs of the process are provided electrically, the process comprises reacting urea to form melamine in a synthesis reactor provided with electrical heating elements, the process further comprises heating the melamine melt electrically during transport and/or using electrically produced heat to remove water from melamine crystals.

Abstract: A process of partial oxidation is performed in a reactor which includes a reaction chamber and a burner assembly, wherein: the burner assembly has a single oxidant nozzle located within an fuel channel, said oxidant nozzle comprises a nozzle pipe and a nozzle outlet, the nozzle pipe and the fuel channel are arranged to produce a diffusion flame, the nozzle outlet has a shape with two or more elongate lobes projecting from a center of the nozzle pipe.

Abstract: A pressure swing adsorption process (PSA) comprising the following steps: feeding an input gas containing H2, CO2 and impurities through a CO2 adsorbent material in a pressure vessel under a high pressure; withdrawing a first H2-rich product gas due to adsorption of CO2 in the adsorbent material; setting the pressure to an intermediate pressure causing the adsorbent material to release a second gas stream; passing a CO2-rich purge stream through the adsorbent material, obtaining a purge gas; setting the pressure to a sub-atmospheric low pressure, so that a CO2-rich product gas is released under vacuum by the adsorbent material; re-pressurizing the vessel to said high pressure; said steps being performed cyclically in a pressure vessel or in a plurality of parallel pressure vessels of a multiple vessel setup.

Abstract: A reactor for the synthesis of urea comprising a vertical shell and perforated baffles or trays (3) arranged to define compartments of the reactor, wherein each baffle comprises an array of individual perforated tiles (10) wherein each tile (101) comprises side walls (101A-101D) and a top face (101F), the side walls having first perforations for the liquid and said top face having second perforations for the gas, wherein said second perforations are smaller than said first perforations, and the tiles are distributed over the baffle with a two-dimensional pattern where adjacent tiles are separated by gaps (17).

Abstract: Reactor for catalytic chemical reactions comprising a catalyst bed with an annular-cylindrical form crossed by a radial flow or mixed axial-radial flow, wherein the bed is delimited by cylindrical walls made gas-permeable by means of slits and the catalyst bed is formed by particles of catalyst with a nominal minimum size such that: the ratio between a transverse dimension of the slits and the nominal minimum size of the particles of catalyst is smaller than or equal to 0.6; the catalyst bed contains no more than 3% by weight of particles with an actual size smaller than said nominal size.

Abstract: A method and system for measuring a liquid level in a pressure vessel, the method comprising: transmitting an electromagnetic signal through a wave guide in the form of an elongate solid rod (5) with bottom end immersed in the liquid and detecting a signal generated by the reflection on the surface of the liquid.

Abstract: Process for the preparation of urea granules comprising the steps of obtaining an aqueous urea solution from one or more synthesis and recovery steps wherein ammonia and carbon dioxide are reacted together, subjecting the aqueous urea solution to an evaporation step wherein water is removed to obtain a urea melt (1), processing and treating said urea melt in a granulation step (7) and optionally in a cooling section (10) to obtain solid urea granules (14); the process further comprises a scrubbing step (3) of granulation offgas and an atmospheric evaporation step (32) to recover a urea solution (2) and a water-saturated air stream (18): the water-saturated air stream is fed back to the scrubbing section (3) without condensation, and the recovered urea solution is conveyed to the granulation step (7).

Abstract: A burner (1) for the production of synthesis gas, configured to feed a reactant stream and an oxidant stream into a reaction chamber, the burner comprising at least one cooled component (11, 12), wherein said cooled component comprises channels (20) to convey a cooling medium, a cooling medium header (24) and a cooling medium collector (25), wherein said channels, said cooling medium header and said cooling medium collector are integrally formed within said cooled component of the burner.

Abstract: A dual-pressure plant for the synthesis of nitric acid comprising: a reactor (4) providing a gaseous effluent (15) containing nitrogen oxides; an absorption tower (6) nitrogen oxides react with water providing raw nitric acid and, said absorption tower operating at a pressure greater than the pressure of the reactor; a compressor (5) elevating the pressure of the reactor effluent (15) to the absorption pressure; said plant also comprising a first bleacher (37) and a second bleacher (7), said first bleacher (37) stripping with air (39) nitrogen oxides from the output stream (27) of the absorption tower (6) providing a partially stripped nitric acid stream (40) and a nitrogen oxides-loaded air stream (41), the former being fed to the second bleacher (7) and the latter being recycled to the delivery-side of said compressor (5).

Abstract: A process for the synthesis of ammonia from a hydrocarbon feedstock, wherein the process includes reforming the hydrocarbon feedstock to produce a make-up gas and converting said make-up gas into ammonia, the process is performed in an ammonia synthesis plant requiring an electric power for operation and also requiring a start-up power (Ps) for start-up, wherein a first electric power (P1) is internally produced in the ammonia plant, and a second electric power (P2) is imported, wherein said second electric power is equal to or greater than said start-up power (Ps).