Abstract: A process for synthesis of urea and a related reaction section of a urea plant, where: ammonia and carbon dioxide are reacted in a liquid phase in a first reaction zone (S1) and heat (Q1) is withdrawn from said first reaction zone to promote the formation of ammonium carbamate, the liquid product (103) from said first reaction zone is then passed to a second reaction zone (S2) distinguished from said first reaction zone, and heat (Q2) is added to said second reaction zone to promote the decomposition of ammonium carbamate into urea and water, where the liquid phase in at least one of said first reaction zone and second reaction zone is kept in a stirred condition. A downflow reactor for carrying out the above process is also disclosed.

Abstract: The present invention concerns process for obtaining melamine at high purity characterized by comprising the steps of:—quenching a melamine melt, deprived of off-gases of the melamine synthesis and containing melamine impurities such as ammeline, ammelide and polycondensates, with an aqueous solution comprising ammonia under conditions such to substantially convert polycondensates into melamine, obtaining a melamine solution substantially free of polycondensates, recovering melamine from said melamine solution by melamine crystallization, obtaining melamine crystals and a melamine crystallization mother liquor,—treating said crystallization melamine mother liquor under conditions such to convert at least a portion of its ammeline content into ammelide and melammine, obtaining a treated mother liquid having at least a reduced ammeline content.

Abstract: The present invention concerns process for obtaining melamine at high purity characterized by comprising the steps of:—quenching a melamine melt, deprived of off-gases of the melamine synthesis and containing melamine impurities such as ammeline, ammelide and polycondensates, with an aqueous solution comprising ammonia under conditions such to substantially convert polycondensates into melamine, obtaining a melamine solution substantially free of polycondensates, recovering melamine from said melamine solution by melamine crystallization, obtaining melamine crystals and a melamine crystallization mother liquor,—treating said crystallization melamine mother liquor under conditions such to convert at least a portion of its ammeline content into ammelide and melammine, obtaining a treated mother liquid having at least a reduced ammeline content.

Abstract: A process for synthesis of urea and a related reaction section of a urea plant, where: ammonia and carbon dioxide are reacted in a liquid phase in a first reaction zone (S1) and heat (Q1) is withdrawn from said first reaction zone to promote the formation of ammonium carbamate, the liquid product (103) from said first reaction zone is then passed to a second reaction zone (S2) distinguished from said first reaction zone, and heat (Q2) is added to said second reaction zone to promote the decomposition of ammonium carbamate into urea and water, where the liquid phase in at least one of said first reaction zone and second reaction zone is kept in a stirred condition. A downflow reactor for carrying out the above process is also disclosed.

Abstract: A cathode for hydrogen evolution in an electrolytic cell, comprising a metallic substrate, and a coating consisting of substantially pure ruthenium oxide, is disclosed. The inventive cathode provides enhanced performance and service life under unsteady and intermittent powering, such as powering from solar cells; a process for coating the metallic substrate is also disclosed.

Abstract: A process for high-pressure, liquid phase conversion of urea into melamine is disclosed, where molten urea is fed to a first reaction zone (S1) where the melamine melt is under mechanical agitation, and a heat input (Q1) is provided to maintain the endothermic reaction, and the liquid is then passed to a second reaction zone (S2) kept at a lower temperature and where further agitation is provided. Embodiments of plants adapted to carry out the process are also disclosed, including multiple stirred reactors in cascade and a single reactor with multiple internal compartments defining said first and second reaction zones.

Abstract: An electrolyser (100) comprising an electrolysis cell stack (101) inside a pressure vessel (115), wherein the first terminal end plate (107a) of the cell stack is integral with one a closed ends of the pressure vessel, thus forming a stationary head (107) of the cell stack equipped with the fluid and electric connections, and the second terminal end plate (108a) of the cell stack is inside the vessel and is free to move in a longitudinal direction in response to thermal expansion or contraction, thus forming a floating head (108) of the stack. The pressure vessel (115) is preferably pressurized using a gaseous product obtained in the process of electrolysis.

Abstract: A cathode for hydrogen evolution in an electrolytic cell, comprising a metallic substrate, and a coating consisting of substantially pure ruthenium oxide, is disclosed. The inventive cathode provides enhanced performance and service life under unsteady and intermittent powering, such as powering from solar cells; a process for coating the metallic substrate is also disclosed.

Abstract: An electrolyser (100) comprising an electrolysis cell stack (101) inside a pressure vessel (115), wherein the first terminal end plate (107a) of the cell stack is integral with one a closed ends of the pressure vessel, thus forming a stationary head (107) of the cell stack equipped with the fluid and electric connections, and the second terminal end plate (108a) of the cell stack is inside the vessel and is free to move in a longitudinal direction in response to thermal expansion or contraction, thus forming a floating head (108) of the stack. The pressure vessel (115) is preferably pressurized using a gaseous product obtained in the process of electrolysis.

Abstract: A method for formaldehyde production through catalytic oxidation of methanol, comprising the steps of feeding to a first oxidation catalytic bed (2) a gas flow comprising methanol and oxygen at a predetermined crossing linear flow rate, obtaining at the outlet of said first catalytic bed (2) a flow of gaseous reaction products comprising unreacted methanol, and feeding the flow of gaseous products to a second oxidation catalytic bed (6) is distinguished by the fact that the flow of gaseous reaction products comprising unreacted methanol is fed to the second catalytic bed (6) with a crossing linear flow rate substantially equal to said predetermined first catalytic bed (2) feeding flow rate.

Abstract: A process for high-pressure, liquid phase conversion of urea into melamine is disclosed, where molten urea is fed to a first reaction zone (S1) where the melamine melt is under mechanical agitation, and a heat input (Q1) is provided to maintain the endothermic reaction, and the liquid is then passed to a second reaction zone (S2) kept at a lower temperature and where further agitation is provided. Embodiments of plants adapted to carry out the process are also disclosed, including multiple stirred reactors in cascade and a single reactor with multiple internal compartments defining said first and second reaction zones.

Abstract: The present invention concerns process for obtaining melamine at high purity characterized by comprising the steps of:—quenching a melamine melt, deprived of off-gases of the melamine synthesis and containing melamine impurities such as ammeline, ammelide and polycondensates, with an aqueous solution comprising ammonia under conditions such to substantially convert polycondensates into melamine, obtaining a melamine solution substantially free of polycondensates, recovering melamine from said melamine solution by melamine crystallisation, obtaining melamine crystals and a melamine crystallization mother liquor,—treating said crystallization melamine mother liquor under conditions such to convert at least a portion of its ammeline content into ammelide and melammine, obtaining a treated mother liquid having at least a reduced ammeline content.

Abstract: A structural component for electrolytic cells of an electrochemical reactor of the filter-press type, comprising a frame (6) supporting its corresponding functional element (7, 7a), a bipolar sheet or a diaphragm, respectively.

Abstract: A method for formaldehyde production through catalytic oxidation of methanol, comprising the steps of feeding to a first oxidation catalytic bed (2) a gas flow comprising methanol and oxygen at a predetermined crossing linear flow rate, obtaining at the outlet of said first catalytic bed (2) a flow of gaseous reaction products comprising unreacted methanol, and feeding the flow of gaseous products to a second oxidation catalytic bed (6) is distinguished by the fact that the flow of gaseous reaction products comprising unreacted methanol is fed to the second catalytic bed (6) with a crossing linear flow rate substantially equal to said predetermined first catalytic bed (2) feeding flow rate.

Abstract: A method of storage and redistribution of electrical energy comprising the steps of: producing hydrogen and oxygen through water electrolysis in an electrolyzer (1) operating under pressure; collecting the hydrogen and oxygen so obtained in respective pressurized tanks (3, 5); reconverting into water and electrical energy hydrogen and oxygen, through an electrochemical reaction of the latter in a fuel cell (9) fed from the tanks (3, 5), distinguishes itself by the fact that in the electrolyzer (1) and in the fuel cell (9) a same liquid phase is used and by the fact that the water produced in the fuel cell (9) by the hydrogen and oxygen reconversion step, is collected in the respective liquid phase and transferred together with the liquid phase to the electrolyzer (1) in order to undergo electrolysis.

Abstract: A method for formaldehyde production through catalytic oxidation of methanol, comprising the steps of feeding to a first oxidation catalytic bed (2) a gas flow comprising methanol and oxygen at a predetermined crossing linear flow rate, obtaining at the outlet of said first catalytic bed (2) a flow of gaseous reaction products comprising unreacted methanol, and feeding the flow of gaseous products to a second oxidation catalytic bed (6) is distinguished by the fact that the flow of gaseous reaction products comprising unreacted methanol is fed to the second catalytic bed (6) with a crossing linear flow rate substantially equal to said predetermined first catalytic bed (2) feeding flow rate.

Abstract: A structural component for electrolytic cells of an electrochemical reactor of the filter-press type, comprising a frame (6) supporting its corresponding functional element (7, 7a), a bipolar sheet or a diaphragm, respectively.

Abstract: A Kit of modular components for the manufacture of an electrochemical reactor (1) of the so-called filter-press type having a substantially tubular body (1a), closed at the opposite ends by end plates (2, 3) and in which is defined a sequence of electrolyte cells (4z, 4b) in fluid with pipes (7 to 10) extended in said body (1a), in a direction parallel to its axis (AA), for the collection and distribution of process fluids, distinguishes itself in that it comprises: a plurality of electrochemically functional flat elements (13, 13a) selected from bipolar elements and separation elements, a plurality of frames (11), all identical to each other, realized with an electrically non-conducting material and structured to enclose and support inside them, in a per se known way, respective pre-selected electrochemically functional flat elements (13, 13a), each of the frames (11) being equipped with an equal plurality of through-holes (14, 14a; 15, 15a; 211, 22; 26, 27) parallel to the axis of the respective frame (11)

Abstract: A method for formaldehyde production through catalytic oxidation of methanol, comprising the steps of feeding to a first oxidation catalytic bed (2) a gas flow comprising methanol and oxygen at a predetermined crossing linear flow rate, obtaining at the outlet of said first catalytic bed (2) a flow of gaseous reaction products comprising unreacted methanol, and feeding the flow of gaseous products to a second oxidation catalytic bed (6) is distinguished by the fact that the flow of gaseous reaction products comprising unreacted methanol is fed to the second catalytic bed (6) with a crossing linear flow rate substantially equal to said predetermined first catalytic bed (2) feeding flow rate.

Abstract: A Kit of modular components for the manufacture of an electrochemical reactor (1) of the so-called filter-press type having a substantially tubular body (1a), closed at the opposite ends by end plates (2, 3) and in which is defined a sequence of electrolyte cells (4a, 4b) in fluid communication with pipes (7 to 10) extended in said body (1a), in a direction parallel to its axis (AA), for the collection and distribution of process fluids, distinguishes itself in that it comprises: