APARELHO DE SÍNTESE DE UREIA PARA REAGIR AMÔNIA E DIÓXIDO DE CARBONO PARA PRODUZIR UREIA, MÉTODO DE SÍNTESE DE UREIA PARA OBTER UM LÍQUIDO DE SÍNTESE DE UREIA, E MÉTODO PARA MELHORAR UM APARELHO DE SÍNTESE DE UREIA EXISTENTE

Abstract

The present invention provides a urea synthesis apparatus with which it is possible to facilitate maintenance of the apparatus, designing and manufacturing of the apparatus, and / or to promote a urea reaction. The present invention specifically provides a urea synthesis apparatus for producing urea by reacting ammonia and carbon dioxide with each other, the urea synthesis apparatus comprising a first urea synthesis tube (R1), a second urea synthesis tube (R2), a condenser (C), a stripper (S) and a means (E) for supplying a first urea synthesis liquid. The condenser (C) is a device for obtaining a condensate liquid by circulating a process fluid in a tube (Ct) and cooling the process fluid with a cooling medium circulating on the shell (Cs) side to condense a mixed gas in an absorption medium, and is a device that is separate from the first urea synthesis tube (R1) and the second urea synthesis tube (R2). The first urea synthesis tube (R1) is a device for obtaining the first urea synthesis liquid from the condensate liquid obtained by the condenser (C), and the second urea synthesis tube (R2) is a device for obtaining a second urea synthesis liquid from the first urea synthesis liquid.

Description

1 / 22 Urea synthesis apparatus for reacting ammonia and iodide. CARBON TO PRODUCE UREA, METHOD OF UREA SYNTHESIS FOR Obtaining a urea synthesis liquid, and a method for improving an existing urea synthesis apparatus. Field of Invention

[0001] The present invention relates to a urea synthesis apparatus that facilitates apparatus maintenance, facilitates apparatus design or manufacture, and / or accelerates a urea reaction. Fundamentals of the invention

[0002] In a urea synthesis process, carbon dioxide and ammonia are generally reacted at high temperature and under high pressure to obtain a urea synthesis liquid. This urea synthesis liquid contains not only urea produced by the synthesis reaction, but also unreacted ammonia, unreacted carbon dioxide, and ammonium carbamate, an intermediate. Furthermore, these unreacted components and intermediates are removed from the urea synthesis liquid to obtain a urea product.

[0003] The unreacted components and intermediate removed from the urea synthesis fluid are generally recycled as feedstocks for urea synthesis. For example, a mixed gas (a gas containing unreacted ammonia and unreacted carbon dioxide) separated from the urea synthesis fluid in a separator is condensed in an absorbent medium in a condenser to obtain a condensed liquid, and the condensed liquid obtained is recycled as a feedstock for urea synthesis. As this absorbent medium, for example, an ammonium carbamate liquid (ammonium carbamate liquid) can be used. Petition 870250066869, dated 07 / 31 / 2025, page 12 / 71 2 / 22 carbamate recycling) separated and recovered from the urea synthesis liquid in a subsequent step can be used.

[0004] However, ammonium carbamate is highly corrosive to metal, and therefore, a portion made in contact with the absorbent medium (recycled carbamate liquid) in the condenser needs to be made of a highly corrosion-resistant metal. Furthermore, a welded portion of the portion made in contact with the absorbent medium needs to be protected from crevice corrosion using full penetration welding without a crevice (e.g., hole welding). In addition, periodic inspections are also necessary to check for the presence or absence of malfunctions, such as corrosion and others.

[0005] On the other hand, typical examples of condensers for condensing the gas mixed in the absorption medium include condensers with a shell and tube structure, such as a fixed-sheet-tube condenser, a U-tube condenser, and others. A fixed-sheet-tube condenser is a condenser in which the tube sheets supporting both ends of the tubes are fixed to either side of a shell. Due to this structure, it is relatively easy to inspect or clean the inside of the tubes, but it is difficult to inspect or clean one side of the shell. Consequently, in a fixed-sheet-tube condenser, a process fluid containing the absorbent medium (recycled carbamate liquid), which is highly corrosive, needs to be allowed to pass through the tubes. Conversely, a U-tube condenser is a condenser in which U-shaped tubes are used and a tube sheet supporting them is fixed to one side. Due to this structure, it is relatively Petition 870250066869, dated 07 / 31 / 2025, p. 13 / 71 3 / 22 It is easy to inspect or clean the inside of the tubes, and on the casing side, it is relatively easy to inspect or clean a tube located on the outside of the tube bundle (group of tubes), but it is relatively difficult to inspect or clean a tube located on the inside of the tube bundle.

[0006] Furthermore, in the condenser, not only condensation but also a urea synthesis reaction occurs. Additionally, in the U-tube condenser, a reaction volume (a volume of process fluid retained in the condenser per unit time) is greater when the process fluid is allowed to pass through the casing side than when it is allowed to flow through the tube side. Consequently, the U-tube condenser in which the process fluid is allowed to pass through the casing side (hereinafter referred to as a submerged U-tube condenser) is superior to the fixed-tube leaf condenser in terms of the acceleration of the urea synthesis reaction within the condenser.

[0007] However, when process fluid is allowed to pass through the side of the casing in the submerged U-tube condenser, due to its structure, the tubes and tube sheet need to be welded by full penetration welding (e.g., inside hole welding) to prevent crevice corrosion. When such special welding is employed, the manufacturing efficiency of the device is reduced and the welding labor costs are also increased. Furthermore, inspection or cleaning of the casing side requires a relatively large space for maintenance between the tube bundle and the inside of the casing. This is a particular obstacle to downsizing an installation. These are problems in the submerged U-tube condenser. Petition 870250066869, dated 07 / 31 / 2025, page 14 / 71 4 / 22

[0008] International patent WO-A 2006-118071 describes a urea synthesis apparatus with an integrated synthesis reactor and condenser. This condenser is a submerged U-tube condenser, in which a process fluid passes through one side of the casing. On the other side, a cooling medium passes through a tube and cools the process fluid on the casing side, and a mixed gas is condensed in an absorption medium under this cooling to obtain a condensed liquid. Furthermore, in this apparatus, the heavy condenser is integrally installed in a lower position than the synthesis reactor and is thus superior in terms of ease of installation or fixing of the equipment compared to when the condenser is integrally installed in a higher position than the synthesis reactor.

[0009] However, this submerged U-tube condenser has some problems, as described above. Furthermore, in reducing the size of an installation, it is difficult for an integrated synthesis reactor and submerged U-tube condenser apparatus, as described in international patent WO-A 2006-118071, to reduce not only the condenser but also the synthesis reactor integrated into it, or if the synthesis reactor is adapted to a required volume, its length becomes too short for its diameter, which depends on the maintenance space requirement for the condenser, and the ideal design is impossible. In other words, the apparatus of international patent WO-A 2006-118071 has room for improvement in these aspects.

[00010] Japanese patent JP-A 2006-102590 describes a reactor comprising a first plate member made of a highly corrosion-resistant metal and a second member of Petition 870250066869, dated 07 / 31 / 2025, page 15 / 71 5 / 22 plate made of a low corrosion-resistant metal, in which while heat exchange tubes are welded to the first plate member by internal hole welding, the second plate member is provided in a detachable form. This reactor is superior in that, as the second plate member is detachable, it is easy to weld portions where the heat exchange tubes are attached to the first plate member or to inspect the device. However, this second plate member is very heavy and its attachment or removal requires a large crane or lifting structure and also requires a large space for attachment or removal work.

[00011] International patent WO-A 01-72700 describes an installation comprising two reactor sections (synthesis reactors). In particular, Figure 3 thereof describes an installation comprising a combined upper synthesis reactor, condenser and lower synthesis reactor, and Figure 4B describes an installation comprising a combined upper synthesis reactor and lower synthesis reactor and a horizontally placed pool condenser.

[00012] This horizontally placed pool condenser described in Figure 4B is a submerged U-tube condenser and therefore has some problems as described previously. Furthermore, the circulation of a synthesis liquid (circulation by which a liquid, gas, or liquid-gas mixture is allowed to flow through the condenser, the upper synthesis reactor, the lower synthesis reactor, a separator, and the condenser in sequence) is carried out by pressure from each device and gravity (a height difference), and thus the circulation flow is susceptible to the pressure of each device and a circulation flow rate is Petition 870250066869, dated 07 / 31 / 2025, page 16 / 71 6 / 22 difficult to control. Furthermore, the relative height at which each device is located is subject to restrictions, and an installation height becomes relatively high.

[00013] On the other hand, the condenser described in Figure 3 is not specifically explained, but is considered a fixed tube sheet condenser from the representation in the figure. Furthermore, international patent WO-A 01-72700 explains that the cooling medium in a heat exchanger (condenser) can sometimes also pass through one side of the casing. However, since the condenser described in Figure 3 is combined with the upper synthesis reactor and the lower synthesis reactor, a worker needs to enter the interior from the cylindrical portion above or below the condenser when performing the inspection of tube welding and a tube sheet of the condenser, and this work involves difficulty. Additionally, since a condenser casing diameter needs to be determined to suit the synthesis reactor, the ideal design of the condenser casing diameter is difficult.Furthermore, as the synthesis reactors are connected above and below the condenser, the height of the device becomes very high. Summary of the Invention

[00014] One objective of the present invention is to solve the problems of each conventional apparatus explained above and to provide a urea synthesis apparatus that allows for easier maintenance of the apparatus, easier design or manufacture of the apparatus, and / or faster urea reaction.

[00015] As a result of conducting intensive studies to achieve the above objective, the present inventors discovered Petition 870250066869, dated 07 / 31 / 2025, page 17 / 71 7 / 22 which is very effective in providing a condenser as a device separate from a reactor and allowing a process fluid to pass through a tube and, in addition, providing at least two reactors and reaching the conclusion of the present invention.

[00016] In other words, the present invention is a urea synthesis apparatus for reacting ammonia and carbon dioxide to produce urea, including a first urea synthesis reactor (R1), a second urea synthesis reactor (R2), a condenser (C), a separator (S) and means (E) for providing a first urea synthesis liquid, wherein the condenser (C) is a device that includes a tube (Ct) inside and for condensing a mixed gas separated in the separator (S) into an absorption medium to obtain a condensed liquid allowing a process fluid containing the absorption medium and the mixed gas to pass through the tube (Ct) and cool the process fluid with a cooling medium that passes through one side of the casing (Cs), the condenser (C) being a device separate from the first urea synthesis reactor (R1) and the second urea synthesis reactor (R2),wherein the first urea synthesis reactor (R1) is a device for reacting at least some components of components in the condensate obtained in the condenser (C) to obtain the first urea synthesis liquid containing urea, unreacted ammonia, unreacted carbon dioxide and water, wherein the means (E) for providing the first urea synthesis liquid are means for providing the first urea synthesis liquid obtained in the first synthesis reactor of, Petition 870250066869, dated 07 / 31 / 2025, page 18 / 71 8 / 22 urea (R1) to the second urea synthesis reactor (R2), wherein the second urea synthesis reactor (R2) is a device for reacting at least some of the components in the first urea synthesis liquid obtained in the first urea synthesis reactor (R1), at least part of the ammonia feedstock and at least part of the carbon dioxide feedstock to obtain a second urea synthesis liquid containing urea, unreacted ammonia, unreacted carbon dioxide and water, and wherein the separator (S) is a device for separating the second urea synthesis liquid obtained in the second urea synthesis reactor (R2) using at least part of the carbon dioxide from the feedstock to separate the mixed gas containing unreacted ammonia and unreacted carbon dioxide from the second urea synthesis liquid.

[00017] Furthermore, the present invention is a method of urea synthesis for obtaining a urea synthesis liquid using the urea synthesis apparatus described above in the present invention.

[00018] Furthermore, the present invention is a method for improving an existing urea synthesis apparatus, the existing urea synthesis apparatus including a urea synthesis reactor, wherein the improvement method includes: adding to the existing urea synthesis apparatus at least one first urea synthesis reactor (R1) and means (E) to provide a first urea synthesis liquid; and when the existing urea synthesis apparatus does not include one or either of a condenser (C) and a separator (S), adding the condenser (C) and / or separator (S) not Petition 870250066869, dated 07 / 31 / 2025, p. 19 / 71 9 / 22 included, and wherein the condenser (C) is a device that includes a tube (Ct) inside and for condensing a mixed gas separated in the separator (S) into an absorption medium to obtain a condensed liquid allowing a process fluid containing the absorption medium and the mixed gas to pass through the tube (Ct) and cool the process fluid with a cooling medium that passes through one side of the casing (Cs), the condenser (C) being a device separate from the first urea synthesis reactor (R1) and a second urea synthesis reactor (R2), wherein the first urea synthesis reactor (R1) is a device for reacting at least part of the components in the condensed liquid obtained in the condenser (C) to obtain the first urea synthesis liquid containing urea, unreacted ammonia, unreacted carbon dioxide and water,wherein the means (E) for providing the first urea synthesis liquid are means for providing the first urea synthesis liquid obtained in the first urea synthesis reactor (R1) to the second urea synthesis reactor (R2), wherein the second urea synthesis reactor (R2) is at least part of the urea synthesis reactor included in the existing urea synthesis apparatus and is a device for reacting at least some components in the first urea synthesis liquid obtained in the first urea synthesis reactor (R1), at least part of ammonia from feedstock and at least part of carbon dioxide from feedstock to obtain a second urea synthesis liquid containing urea, unreacted ammonia, unreacted carbon dioxide and water, and wherein the separator (S) is a device for separating, Petition 870250066869, dated 07 / 31 / 2025, page 20 / 71 10 / 22 the second urea synthesis liquid obtained in the second urea synthesis reactor (R2) using at least part of the carbon dioxide from the feedstock to separate the mixed gas containing unreacted ammonia and unreacted carbon dioxide from the second urea synthesis liquid.

[00019] In the urea synthesis apparatus of the present invention, the process fluid can pass through the tube (Ct) of the condenser (C) and the cooling medium can pass through the side of the casing (Cs) and thus special welding (e.g., internal hole welding) is unnecessary and maintenance for inspection or cleaning can be easily performed.

[00020] Furthermore, in the urea synthesis apparatus of the present invention, the condenser (C) is a device separate from the first urea synthesis reactor (R1) and the second urea synthesis reactor (R2), and thus inspection of the interior of the condenser (C) is easy and the ideal design of a condenser (C) casing diameter is easy and the heights of the synthesis reactors can also be reduced, compared with an apparatus in which it is integrated with it.

[00021] Furthermore, in the urea synthesis apparatus of the present invention, a reaction volume of the condenser (C) is relatively small, but the two urea synthesis reactors (R1) and (R2) are included and thus the apparatus can accelerate the urea reaction while suppressing uncondensed gas, optimizing the reaction conditions of each synthesis portion. Brief Description of the Drawings

[00022] [FIG. 1] A process flow diagram showing a first embodiment of the apparatus of the present invention. Petition 870250066869, dated 07 / 31 / 2025, page 21 / 71 11 / 22

[00023] [FIG. 2] A process flow diagram showing a second embodiment of the apparatus of the present invention.

[00024] [FIG. 3] A process flow diagram showing a third embodiment of the apparatus of the present invention.

[00025] [FIG. 4] A process flow diagram showing a fourth embodiment of the apparatus of the present invention. Modalities of the Invention

[00026] The urea synthesis apparatus of the present invention is an apparatus for reacting ammonia and carbon dioxide to produce urea and includes a first urea synthesis reactor (R1), a second urea synthesis reactor (R2), a condenser (C), a separator (S) and means (E) for providing a first urea synthesis liquid. Hereafter, each of them is explained. <Condensador (C)>

[00027] The condenser (C) is a device that includes a tube (Ct) inside and condenses a mixed gas separated in the separator (S) into an absorption medium to obtain a condensed liquid, allowing a process fluid containing the absorption medium and the mixed gas to pass through the tube (Ct) and cools the process fluid with a cooling medium that passes through one side of the casing (Cs). Consequently, it does not require special welding (e.g., internal hole welding) and can reduce the space required for maintenance, inspection, or cleaning. Furthermore, if corrosive process fluid at high temperature and high pressure is allowed to flow through the side of the casing (Cs), both the tube (Ct) and the casing (Cs) need to be formed of a corrosion-resistant material, but the present invention allows the process fluid to pass through the tube. Petition 870250066869, dated 07 / 31 / 2025, page 22 / 71 12 / 22 (Ct) makes it possible to use a corrosion-resistant material only for the tube. The corrosion-resistant material is, for example, a high-chromium austenitic steel, a duplex alloy, titanium, or 316L austenitic steel or similar. As the corrosive process fluid at a high temperature and high pressure is allowed to flow through the tube (Ct), the design restrictions on the casing (Cs) can be reduced, and the casing (Cs) can be formed from an inexpensive and highly reliable material, for example, carbon steel, a low-alloy steel, or similar.

[00028] A temperature and pressure for condensation in the condenser (C) are preferably 160 to 200°C and preferably 13 to 25 MPa, respectively.

[00029] The condenser (C) is a separate device from the first urea synthesis reactor (R1) and the second urea synthesis reactor (R2). Consequently, inspection of the interior of the condenser (C) is easy and the ideal design of a condenser (C) casing diameter is easy.

[00030] A fixed tube sheet condenser is preferably used as the condenser (C) in terms of not requiring special welding and easy inspection or cleaning. Furthermore, the tube (Ct) is preferably a straight tube. However, the present invention is not limited to this. For example, a condenser having a U-shaped tube head at one rear end of the head can also be used as the condenser (C). It can be configured in such a way that a U-shaped tube is used as the tube (Ct) and the tube (Ct) is supported by a tube sheet to secure one side of the U-shape. <Primeiro reator de síntese de ureia (R1)>

[00031] The first urea synthesis reactor (R1) is a Petition 870250066869, dated 07 / 31 / 2025, page 23 / 71 13 / 22 device for reacting at least some components of components in the condensed liquid obtained in the condenser (C) to obtain the first urea synthesis liquid containing urea, unreacted ammonia, unreacted carbon dioxide and water. This first urea synthesis reactor (R1) complements the urea synthesis function in the condenser (C) and the apparatus can accelerate the urea reaction while suppressing an unreacted gas optimizing the reaction conditions of this first urea synthesis reactor (R1) and the second urea synthesis reactor (R2) described later.

[00032] The preferred reaction conditions in the first urea synthesis reactor (R1) are different from those in the second urea synthesis reactor (R2) described later. Specifically, a temperature and pressure for urea synthesis in the first urea synthesis reactor (R1) are preferably 160 to 200°C and preferably 13 to 25 MPa, respectively. In addition, N / C is preferably 2.5 to 4.0.

[00033] The structure of a synthesis reactor used as the first urea synthesis reactor (R1) is not particularly limited. A synthesis reactor of a publicly known structure used for urea synthesis can be used. <Meios (E) para fornecer o primeiro líquido de síntese de ureia >

[00034] The means (E) for supplying the first urea synthesis liquid are means for supplying the first urea synthesis liquid obtained in the first urea synthesis reactor (R1) to the second urea synthesis reactor (R2).

[00035] This means (E) to provide the first urea synthesis liquid preferably includes an ejector. Furthermore, this ejector is preferably driven by ammonia. Petition 870250066869, dated 07 / 31 / 2025, page 24 / 71 14 / 22 raw material as a drive source. In this case, the means (E) for supplying the first urea synthesis liquid also function as circulation means and it becomes easy to control a circulation flow rate of the process fluid flowing through the devices that constitute the synthesis apparatus (stage) (the condenser, the first synthesis reactor, the second synthesis reactor and the separator) in sequence and, furthermore, it is also possible to install the first urea synthesis reactor (R1) and / or the second urea synthesis reactor (R2) in the ground. However, the present invention is not limited to the same. For example, a pump can also be used as the means (E) for supplying the first urea synthesis liquid. <Segundo reator de síntese de ureia (R2)>

[00036] The second urea synthesis reactor (R2) is a device for reacting at least some of the components in the first urea synthesis liquid obtained in the first urea synthesis reactor (R1), at least part of the ammonia feedstock and at least part of the carbon dioxide feedstock to obtain a second urea synthesis liquid containing urea, unreacted ammonia, unreacted carbon dioxide and water.

[00037] The preferred temperature and pressure in the second urea synthesis reactor (R2) are different from the preferred temperature and pressure mentioned above in the first urea synthesis reactor (R1). Specifically, a temperature and pressure for urea synthesis in the second urea synthesis reactor (R2) are preferably 170 to 210°C and preferably 13 to 25 MPa, respectively. In addition, N / C is preferably 3 to 4.5. Petition 870250066869, dated 07 / 31 / 2025, page 25 / 71 15 / 22

[00038] The structure of a synthesis reactor used as the second urea synthesis reactor (R2) is not particularly limited. A synthesis reactor of a publicly known structure used for urea synthesis can be used.

[00039] Furthermore, the first urea synthesis reactor (R1) and the second urea synthesis reactor (R2) can be separate devices from each other or can form an integrated device in a single partitioned vessel configuration. Additionally, it can be a vertical device or a horizontal device. <Separador (S)>

[00040] The separator (S) is a device for separating the second urea synthesis liquid obtained in the second urea synthesis reactor (R2) using at least part of the carbon dioxide from the feedstock to separate the mixed gas containing unreacted ammonia and unreacted carbon dioxide from the second urea synthesis liquid.

[00041] A temperature or pressure in the separator (S) is not particularly limited. Any publicly known separation temperature or pressure used for urea synthesis may be employed. Furthermore, a separator structure (S) is also not particularly limited. A separator of a publicly known structure used for urea synthesis may be used. Urea synthesis method

[00042] The urea synthesis method of the present invention is a method for obtaining a urea synthesis liquid using the urea synthesis apparatus of the present invention explained above. This urea synthesis method facilitates apparatus maintenance, design, or Petition 870250066869, dated 07 / 31 / 2025, page 26 / 71 16 / 22 manufacturing of the apparatus and / or acceleration of the urea reaction as mentioned above. <Método para melhorar o aparelho de síntese de ureia existente >

[00043] It is also possible to improve an existing urea production apparatus to form the urea synthesis apparatus of the present invention by adding to it at least the first urea synthesis reactor (R1) and the means (E) to provide the first urea synthesis liquid. This improvement method allows for easier maintenance of the existing urea synthesis apparatus, easier design or manufacture of the apparatus, and / or faster urea reaction.

[00044] Furthermore, this enhancement method allows at least part of a urea synthesis reactor included in the existing urea synthesis apparatus to function as the second urea synthesis reactor (R2) in the present invention. When the existing urea synthesis apparatus includes only one urea synthesis reactor, the second urea synthesis reactor (R2) in this enhancement method is the urea synthesis reactor included in the existing urea synthesis apparatus. Conversely, when the existing urea synthesis apparatus includes two or more urea synthesis reactors, for example, when an internally partitioned tubular device is allowed to function as the two or more urea synthesis reactors, or similar, part or all of the two or more urea synthesis reactors may be the second urea synthesis reactor (R2).

[00045] Furthermore, when the existing urea synthesis apparatus does not include one or either of a capacitor (C) and a separator (S), the capacitor (C) and / or separator (S) may Petition 870250066869, dated 07 / 31 / 2025, p. 27 / 71 17 / 22 to be added. For example, when the existing urea synthesis apparatus is a solution recycling type urea synthesis apparatus (non-separation type), the condenser (C) and separator (S) are also added. Furthermore, for example, when the existing urea synthesis apparatus is an ammonia removal type urea synthesis apparatus, a separator thereof (a separator to which no carbon dioxide is supplied) is removed and, instead, the separator (S) in the present invention is also added.

[00046] From here on, the embodiments of the apparatus of the present invention are explained using drawings.

[00047] FIG. 1 is a process flow diagram showing a first embodiment of the apparatus of the present invention. In this first embodiment, the first urea synthesis reactor (R1) and the second urea synthesis reactor (R2) are devices separate from each other. Compared with other embodiments, this first embodiment is advantageous insofar as, since the urea synthesis reactors are separate from each other, the placement or sizing of the device can be flexibly designed. Furthermore, it is also suitable for improvements using an existing urea synthesis reactor.

[00048] In FIG. 1, an absorbent medium is supplied to an upper side of the condenser (C) through a line 11 and a mixed gas separated in the separator (S) is supplied to an upper side of the condenser (C) through a line 12. The condenser (C) includes the tube (Ct) inside and a process fluid (the absorbent medium and the mixed gas) is allowed to pass through the tube (Ct). A distribution device is provided inside a channel of the condenser (C) and is Petition 870250066869, dated 07 / 31 / 2025, page 28 / 71 18 / 22 is configured to allow the absorbent medium and the mixed gas to pass through each tube (Ct) uniformly. On the other hand, a cooling medium is stored in a steam drum (D) and this cooling medium is supplied to one side of the condenser (C) casing (Cs) through a line 13, recovered through a line 14 and allowed to circulate through this path. The process fluid passing through the tube (Ct) is cooled by this cooling medium. In addition, the mixed gas is condensed in the absorbent medium by this cooling to obtain a condensed liquid.

[00049] In the first urea synthesis reactor (R1) in FIG. 1, the condensate obtained in the condenser (C) is supplied from a lower side of the condenser (C) through a line 15. Furthermore, at least some of the components in the condensate are reacted to obtain a first urea synthesis liquid. This first urea synthesis liquid is supplied through a line 16 to an ejector, the means (E) to supply the first urea synthesis liquid, and this ejector supplies it to the second urea synthesis reactor (R2) through a line 17. A drive source for this ejector is the ammonia feedstock supplied from a line 18. On the other hand, the condensate supplied through line 15 also contains some mixed gas not condensed in the condenser (C). This mixed gas is separated in the first urea synthesis reactor (R1) and supplied to a device in a subsequent step via line 19.A scrubber can be installed at a gas outlet of the first urea synthesis reactor (R1) to recover some of the separated mixed gas.

[00050] In the second urea synthesis reactor (R2) in FIG. 1, Petition 870250066869, dated 07 / 31 / 2025, page 29 / 71 19 / 22 at least some components in the first urea synthesis liquid, at least part of the ammonia from the raw material added and mixed to the first urea synthesis liquid as a drive source for the ejector and at least part of the carbon dioxide from the raw material supplied through a line 20 are reacted to obtain a second urea synthesis liquid.

[00051] In the separator (S) in FIG. 1, the second urea synthesis liquid obtained in the second urea synthesis reactor (R2) is supplied through line 21. Furthermore, this second urea synthesis liquid is removed using at least part of the raw material carbon dioxide supplied through line 22 to separate the mixed gas containing unreacted ammonia and unreacted carbon dioxide from the second urea synthesis liquid. Heating in this separation is carried out by steam supplied and discharged through lines 23 and 24. The separated mixed gas is supplied to the condenser (C) through line 12 as described above. Conversely, a urea synthesis liquid after separation of the mixed gas is supplied through line 25 to a device in a subsequent step (e.g., a purification device).

[00052] FIG. 2 is a process flow diagram showing a second embodiment of the apparatus of the present invention. In this second embodiment, the first urea synthesis reactor (R1) and the second urea synthesis reactor (R2) form an integrated device in a single partitioned vessel configuration and form a vertical device with the first urea synthesis reactor (R1) located on one lower side and the second urea synthesis reactor (R2) Petition 870250066869, dated 07 / 31 / 2025, page 30 / 71 20 / 22 located on an upper side. Compared to other modalities, this second modality is advantageous insofar as a reduction in pressure-resistant limbs or a reduction in the weight of a device is achieved, and the area required for placement can be reduced.

[00053] Each device in FIG. 2 is the same as each device shown in FIG. 1, except that the first urea synthesis reactor (R1) and the second urea synthesis reactor (R2) are changed to the integrated device. Furthermore, each line is also the same as each line shown in FIG. 1.

[00054] FIG. 3 is a process flow diagram showing a third embodiment of the apparatus of the present invention. In this third embodiment, the first urea synthesis reactor (R1) and the second urea synthesis reactor (R2) form an integrated device in a single partitioned vessel configuration and form a vertical device with the first urea synthesis reactor (R1) located on an upper side and the second urea synthesis reactor (R2) located on a lower side.

[00055] Each device in FIG. 3 is the same as each device shown in FIG. 2, except that the vertical locations of the first urea synthesis reactor (R1) and the second urea synthesis reactor (R2) are reversed, and the separator gas and absorbent medium are supplied below the condenser tube (Ct) and allowed to flow through the tube (Ct) upwards from below. Each line is the same as each line shown in FIG. 2, except that, from FIG. 2, line 11 to supply the absorbent medium to the upper side of the condenser (C) is changed to a line to supply it to a Petition 870250066869, dated 07 / 31 / 2025, page 31 / 71 21 / 22 lower side, line 12 to supply the mixed gas to the upper side of the condenser (C) is changed to a line to supply it to a lower side and line 15 to discharge the condensed liquid from the lower side of the condenser (C) is changed to a line to discharge it from an upper side. These line changes are made to adapt them to the changing locations of the first urea synthesis reactor (R1) and the second urea synthesis reactor (R2). Compared to other embodiments, this third embodiment is advantageous in that, as the channel and tube portion (Ct) of the condenser are filled with liquid and gas, a retention time during which they remain within the condenser (reaction time) is increased and the synthesis of urea from the absorbed components is accelerated.

[00056] FIG. 4 is a process flow diagram showing a fourth embodiment of the apparatus of the present invention. In this fourth embodiment, the first urea synthesis reactor (R1) and the second urea synthesis reactor (R2) form an integrated device in a single partitioned vessel configuration and form a horizontal device with the first urea synthesis reactor (R1) and the second urea synthesis reactor (R2) connected in series to each other. Compared with other embodiments, this fourth embodiment is advantageous in that the installation height can be reduced.

[00057] Each device in FIG. 4 is the same as each device shown in FIG. 2, except that the first urea synthesis reactor (R1) and the second urea synthesis reactor (R2) are changed to the horizontal device in which they are connected in series to each other. Furthermore, each line Petition 870250066869, dated 07 / 31 / 2025, pp. 32 / 71 22 / 22 is also the same as each line shown in FIG. 2. Industrial Applicability

[00058] The urea synthesis apparatus of the present invention facilitates apparatus maintenance, facilitates apparatus design or manufacture, and / or accelerates the urea reaction, and thus can be very appropriately applied to a urea production plant. Furthermore, it is also useful for improving an existing urea synthesis apparatus.

[00059] List of Reference Signs R1 first urea synthesis reactor R2 second urea synthesis reactor C capacitor CT tube Cs casing S separator And means to provide the first urea synthesis liquid D steam drum 11-25 line Petition 870250066869, dated 07 / 31 / 2025, pp. 33 / 71

Claims

1 / 5 - CLAIMS - 1. UREA SYNTHESIS APPARATUS FOR REACTING AMMONIA AND CARBON DIOXIDE TO PRODUCE UREA, characterized in that it comprises a first urea synthesis reactor (R1), a second urea synthesis reactor (R2), a condenser (C), a separator (S) and means (E) for providing a first urea synthesis liquid, wherein the condenser (C) is a device that includes a tube (Ct) inside and for condensing a mixed gas separated in the separator (S) into an absorption medium to obtain a condensed liquid allowing a process fluid containing the absorption medium and the mixed gas to pass through the tube (Ct) and cool the process fluid with a cooling medium that passes through one side of the casing (Cs), the condenser (C) being a device separate from the first urea synthesis reactor (R1) and the second urea synthesis reactor (R2),wherein the first urea synthesis reactor (R1) is a device for reacting at least some components of components in the condensate obtained in the condenser (C) to obtain the first urea synthesis liquid containing urea, unreacted ammonia, unreacted carbon dioxide and water, and in the first urea synthesis reactor (R1), the temperature and pressure for urea synthesis and N / C are 160 to 200°C, 13 to 25 MPa and 2.5 to 4.0, respectively, wherein the means (E) for supplying the first urea synthesis liquid are means for supplying the first urea synthesis liquid obtained in the first urea synthesis reactor (R1) to the second urea synthesis reactor (R2), wherein the second urea synthesis reactor (R2) is a Petition 870260064926, dated 01 / 07 / 2026, page. 7 / 16 2 / 5 device for reacting at least some of the components in the first urea synthesis liquid obtained in the first urea synthesis reactor (R1),at least part of the raw material is ammonia and at least part is carbon dioxide to obtain a second urea synthesis liquid containing urea, unreacted ammonia, unreacted carbon dioxide and water, and in the second urea synthesis reactor (R2), the temperature and pressure for urea synthesis and N / C are 170 to 210°C, 13 to 25 MPa and 3 to 4.5, respectively, and wherein the separator (S) is a device for separating the second urea synthesis liquid obtained in the second urea synthesis reactor (R2) using at least part of the carbon dioxide from the raw material to separate the mixed gas containing unreacted ammonia and unreacted carbon dioxide from the second urea synthesis liquid.

2. Apparatus, according to claim 1, characterized in that the means (E) for providing the first urea synthesis liquid comprises an ejector and the ejector is driven by ammonia from the feedstock as a drive source.

3. Apparatus according to claim 1, characterized in that the first urea synthesis reactor (R1) and the second urea synthesis reactor (R2) are devices separate from each other.

4. Apparatus according to claim 1, characterized in that the first urea synthesis reactor (R1) and the second urea synthesis reactor (R2) form an integrated device in a single partitioned vessel configuration.

5. Apparatus, according to claim 1, Petition 870260064926, dated 01 / 07 / 2026, page 8 / 16 3 / 5 characterized in that the mixed gas from the separator (S) and the absorbent medium are supplied below the condenser (C) and allowed to flow upwards.

6. Apparatus, according to claim 1, characterized in that the means (E) for supplying the first urea synthesis liquid function as circulation means and control the circulation flow rate of the process fluid flowing through the condenser (C), the first synthesis reactor (R1), the second synthesis reactor (R2) and the separator (S) in sequence.

7. A METHOD FOR SYNTHESIS OF UREA TO OBTAIN A UREA SYNTHESIS LIQUID, characterized by comprising using the urea synthesis apparatus as defined in claim 1.

8. METHOD FOR IMPROVING AN EXISTING UREA SYNTHESIS APPARATUS, the existing urea synthesis apparatus including a urea synthesis reactor, characterized in that the improvement method comprises: adding to the existing urea synthesis apparatus at least one first urea synthesis reactor (R1) and means (E) to provide a first urea synthesis liquid; and wherein the existing urea synthesis apparatus does not include one or either of a condenser (C) and a separator (S), add the condenser (C) and / or separator (S) not included, and wherein the condenser (C) is a device that includes a tube (Ct) inside and for condensing a mixed gas separated in the separator (S) into an absorption medium to obtain a condensed liquid allowing a process fluid containing the absorption medium and the mixed gas to pass through the tube (Ct) Petition 870260064926, dated 01 / 07 / 2026,page. 9 / 16 4 / 5 and cool the process fluid with a cooling medium passing through one side of the casing (Cs), the condenser (C) being a device separate from the first urea synthesis reactor (R1) and a second urea synthesis reactor (R2), wherein the first urea synthesis reactor (R1) is a device for reacting at least part of the components in the condensed liquid obtained in the condenser (C) to obtain the first urea synthesis liquid containing urea, unreacted ammonia, unreacted carbon dioxide and water, and in the first urea synthesis reactor (R1), a temperature and pressure for urea synthesis, and N / C are 160 to 200°C, 13 to 25 MPa and 2.5 to 4.0, respectively, wherein the means (E) for providing the first urea synthesis liquid are means for providing the first urea synthesis liquid obtained in the first reactor from urea synthesis (R1) to the second urea synthesis reactor (R2),wherein the second urea synthesis reactor (R2) is at least part of the urea synthesis reactor included in the existing urea synthesis apparatus and is a device for reacting at least some components in the first urea synthesis liquid obtained in the first urea synthesis reactor (R1), at least part of ammonia from feedstock and at least part of carbon dioxide from feedstock to obtain a second urea synthesis liquid containing urea, unreacted ammonia, unreacted carbon dioxide and water, and in the second urea synthesis reactor (R2), the temperature and pressure for urea synthesis and N / C are 170 to 210°C, 13 to 25 MPa and 3 to 4.5, respectively, and wherein the separator (S) is a device for separating the second urea synthesis liquid obtained in the second reactor. Petition 870260064926, of 01 / 07 / 2026pg 10 / 16 5 / 5 of urea synthesis (R2) using at least part of the carbon dioxide from the feedstock to separate the mixed gas containing unreacted ammonia and unreacted carbon dioxide from the second urea synthesis liquid., 9. Method according to claim 8, characterized in that the second urea synthesis reactor (R2) is a urea synthesis reactor included in the existing urea synthesis apparatus.

10. Method according to claim 8, characterized in that the mixed gas from the separator (S) and the absorbent medium are supplied below the condenser (C) and allowed to flow upwards.

11. Method according to claim 8, characterized in that the means (E) for supplying the first urea synthesis liquid function as circulation means and control the circulation flow rate of the process fluid flowing through the condenser (C), the first synthesis reactor (R1), the second synthesis reactor (R2) and the separator (S) sequentially. Petition 870260064926, dated 01 / 07 / 2026, page 11 / 16

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