WO2023156360A1 - Optimized process condensate preparation - Google Patents

Optimized process condensate preparation Download PDF

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Publication number
WO2023156360A1
WO2023156360A1 PCT/EP2023/053567 EP2023053567W WO2023156360A1 WO 2023156360 A1 WO2023156360 A1 WO 2023156360A1 EP 2023053567 W EP2023053567 W EP 2023053567W WO 2023156360 A1 WO2023156360 A1 WO 2023156360A1
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WO
WIPO (PCT)
Prior art keywords
process condensate
purification device
coarse
urea
condensate purification
Prior art date
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PCT/EP2023/053567
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German (de)
French (fr)
Inventor
Ivo Müller
Original Assignee
Thyssenkrupp Industrial Solutions Ag
Thyssenkrupp Ag
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Filing date
Publication date
Priority claimed from LU102914A external-priority patent/LU102914B1/en
Priority claimed from DE102022201727.7A external-priority patent/DE102022201727A1/en
Application filed by Thyssenkrupp Industrial Solutions Ag, Thyssenkrupp Ag filed Critical Thyssenkrupp Industrial Solutions Ag
Publication of WO2023156360A1 publication Critical patent/WO2023156360A1/en

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
    • B01D3/34—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping with one or more auxiliary substances
    • B01D3/38—Steam distillation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
    • B01D3/009—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping in combination with chemical reactions
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
    • B01D3/14—Fractional distillation or use of a fractionation or rectification column
    • B01D3/143—Fractional distillation or use of a fractionation or rectification column by two or more of a fractionation, separation or rectification step
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/46—Removing components of defined structure
    • B01D53/54—Nitrogen compounds
    • B01D53/58—Ammonia
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/02—Treatment of water, waste water, or sewage by heating
    • C02F1/04—Treatment of water, waste water, or sewage by heating by distillation or evaporation
    • C02F1/10—Treatment of water, waste water, or sewage by heating by distillation or evaporation by direct contact with a particulate solid or with a fluid, as a heat transfer medium
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C273/00—Preparation of urea or its derivatives, i.e. compounds containing any of the groups, the nitrogen atoms not being part of nitro or nitroso groups
    • C07C273/02—Preparation of urea or its derivatives, i.e. compounds containing any of the groups, the nitrogen atoms not being part of nitro or nitroso groups of urea, its salts, complexes or addition compounds
    • C07C273/04—Preparation of urea or its derivatives, i.e. compounds containing any of the groups, the nitrogen atoms not being part of nitro or nitroso groups of urea, its salts, complexes or addition compounds from carbon dioxide and ammonia
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C273/00—Preparation of urea or its derivatives, i.e. compounds containing any of the groups, the nitrogen atoms not being part of nitro or nitroso groups
    • C07C273/02—Preparation of urea or its derivatives, i.e. compounds containing any of the groups, the nitrogen atoms not being part of nitro or nitroso groups of urea, its salts, complexes or addition compounds
    • C07C273/14—Separation; Purification; Stabilisation; Use of additives
    • C07C273/16—Separation; Purification
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/10—Inorganic compounds
    • C02F2101/16—Nitrogen compounds, e.g. ammonia
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/30—Organic compounds
    • C02F2101/38—Organic compounds containing nitrogen
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
    • C02F2103/34—Nature of the water, waste water, sewage or sludge to be treated from industrial activities not provided for in groups C02F2103/12 - C02F2103/32
    • C02F2103/36—Nature of the water, waste water, sewage or sludge to be treated from industrial activities not provided for in groups C02F2103/12 - C02F2103/32 from the manufacture of organic compounds
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2301/00—General aspects of water treatment
    • C02F2301/08—Multistage treatments, e.g. repetition of the same process step under different conditions

Definitions

  • the invention relates to the processing of the process condensate obtained in the urea synthesis.
  • the process condensate occurring in the urea synthesis contains both ammonia and urea as impurities. It is therefore cleaned in a three-stage process before it is used again.
  • ammonia is often removed at temperatures of around 115 to 140 °C.
  • a hydrolysis is then carried out at temperatures of around 190 to 200° C. and usually more than 15 bar and for a time of 60 to 120 minutes, in which urea decomposes into ammonia and carbon dioxide.
  • the resulting ammonia and carbon dioxide are then removed in a third step.
  • the separation processes in the first and third step are identical, so these two steps are usually carried out in a column that is only split down the middle to interpose the second step.
  • This three-step process makes the entire process condensate stream very clean, specifically less than 3 ppm ammonia and less than 3 ppm urea. This is correspondingly complex and requires a lot of energy. There are also applications with less high purity requirements, especially with the exhaust gas scrubbing required for urea formation, in particular urea granulation or urea prilling, especially since urea is introduced there as an impurity from the exhaust gas.
  • US 2019 / 0177180 A1 proposes separating a partial flow after the first stage and feeding it to the exhaust gas scrubber. However, this means that the streams in the first stage and the third stage, which are in a common column, have very different amounts, which can have a disadvantageous effect on the design and operation.
  • US Pat. No. 4,652,678 A discloses a method for recovering valuable components from a waste gas stream from urea synthesis. i A method for removing urea, ammonia and carbon dioxide from a dilute aqueous solution is known from US Pat. No. 4,410,503 A.
  • the object of the invention is to provide a process condensate treatment which, on the one hand, has the high purity for the usual uses and, on the other hand, has a lower purity for the waste gas scrubbing, and at the same time enables optimal process management with minimal energy consumption.
  • the system network serves to produce a urea molding material, in particular urea granules or urea prills.
  • granulate or prill are usually used; they are particulate, agglomerated material which has a particle size suitable for application as a fertilizer and is usually produced in a shaping step following the synthesis, ie granulation or prilling.
  • the plant network has at least one urea synthesis device and one urea forming device.
  • the plant network usually also has a device for synthesizing ammonia and, in many cases, a reformer for producing the hydrogen. Ammonia is produced from hydrogen and nitrogen in the device for the synthesis of ammonia.
  • urea is produced with carbon dioxide in the urea synthesis device and partly processed with other components, for example ammonium nitrate, sulfur compounds, lime and the like, in the urea forming device to form granules which are widely used in particular as fertilizers.
  • the plant network can optionally also have a nitric acid synthesis device and optionally also an ammonium nitrate synthesis device.
  • ammonium nitrate for example, can be mixed with the urea as a further component and shaped together, in particular granulated.
  • the plant network has a process condensate purification device, wherein the process condensate purification device for separating ammonia and Urea is formed from the process condensate of the urea synthesis device. This enables further use of the water inside or outside of the system network or its disposal.
  • the process condensate purification device has a purification flow up to the process condensate outlet.
  • the purification stream usually leads the process condensate through three stages in order to achieve a high degree of purity of the process condensate. This means that the purified process condensate can be used in a variety of ways.
  • the plant network has a shaping exhaust air washing device, which is connected to the urea shaping device and is used to clean the exhaust gases of this device.
  • the molding exhaust air washing device serves to remove the urea that has gotten into the exhaust air by washing it out with water, thus reducing the emission of nitrogen.
  • the forming effluent scrubber includes a second stage in which a scrub with an acidic medium removes ammonia.
  • the plant network has a coarse process condensate purification device in addition to the process condensate purification device.
  • the coarse process condensate purification device has a coarse purification stream. In the coarse purification flow, a simpler purification took place compared to the process condensate purification device, so that the roughly purified process condensate has a lower purity, but the effort required for the coarse purification is correspondingly reduced.
  • the coarse purification stream is separate and distinct from the purification stream.
  • the coarse process condensate purification device and the process condensate purification device are thus two separate devices and the coarse process condensate purification device is not just, for example, the first stage of the process condensate purification device.
  • the urea synthesis device is connected to the process condensate purification device and the coarse process condensate purification device for transferring process condensate.
  • the coarse process condensate purification device is equipped with the
  • the flow of the process condensate of the urea synthesis device is divided into two partial flows.
  • a first partial flow goes into the prior art process condensate purification device. Since this stream is completely purified, the first stage and the third Stage designed for the same volume flow and are also operated in this way.
  • the new coarse process condensate purification device, into which a second partial flow is fed, is arranged parallel to the conventional process condensate purification device.
  • the need for the first partial flow and the second partial flow can be approximately the same, for example.
  • the water flow required for the forming exhaust air washing device is cleaned sufficiently in the coarse process condensate cleaning device only for this application and is therefore much more energy-efficient.
  • a removal of the urea from the process condensate is not necessary for its use in the exhaust air scrubber.
  • the coarse process condensate purification device has only one stage and therefore, above all, no hydrolysis in a second step.
  • the amount of ammonia in the process condensate can be specifically adjusted by the separate coarse process condensate purification device.
  • the ammonia released from the exhaust air during the forming process, in particular during the granulation or prilling process is preferably removed by acidic scrubbing, for example with nitric acid or sulfuric acid.
  • the associated ammonia salt is formed, which can also be used as a fertilizer or as a feedstock for other processes, for example for the production of urea ammonium nitrate (UAN).
  • UAN urea ammonium nitrate
  • the amount of heat required for the process condensate purification device is provided in the form of steam, which is predominantly fed directly into the process and is thus itself the process condensate. If the process condensate cleaning takes place more energy-efficiently, this amount of steam fed in can be reduced. This leads to a reduction in the amount of process condensate that occurs, since the saved steam means that no additional water is introduced, which would increase the amount of process condensate.
  • the strict separation of the process condensate purification device and the purification flow from the coarse process condensate purification device and the coarse purification flow results in two fundamental advantages.
  • the first benefit is that in particular the process condensate purification device is designed for a constant continuous purification stream. All stages are therefore designed for an identical volume flow, which is advantageous.
  • the second advantage is that retrofitting as part of a capacity expansion is easily possible.
  • an existing process condensate purification device can continue to be operated and a new, additional and separate coarse process condensate purification device is installed, which cleans the process condensate flow added by the capacity expansion in a simple and reduced manner and for corresponding Applications, in particular the forming exhaust air scrubber provides.
  • a capacity expansion of the process condensate purification device can thus advantageously be dispensed with.
  • the coarse process condensate purification device is designed in one stage for the removal of ammonia.
  • the coarse process condensate purification device is designed in the form of a column, in particular a tray column or a packed column.
  • a second stage for the hydrolysis of urea to form ammonia and CO2 is therefore preferably not part of the coarse process condensate purification device.
  • the coarse process condensate purification device has a first heat exchanger.
  • the first heat exchanger is designed to preheat the process condensate stream coming from the urea synthesis device. This takes place in that the heat exchanger is designed to cool the coarsely cleaned process condensate flow emerging from the coarse process condensate purification device. The process heat can thus be kept in the coarse process condensate purification device.
  • the coarse process condensate purification device has a second heat exchanger.
  • the second heat exchanger is designed to condense the gas stream exiting the coarse process condensate purification device.
  • the gas mixture can which contains in particular water, ammonia and carbon dioxide, are condensed.
  • This process condensate can also be referred to as a carbamate solution, since the ammonia and carbon dioxide contained there partially react with one another in an aqueous solution, to form carbamate, among other things.
  • the second heat exchanger and the coarse process condensate purification device are preferably connected to a carbamate return line. As a result, a partial flow of the carbamate solution can be fed back into the coarse process condensate purification device.
  • the proportion of water in the carbamate solution can be reduced if necessary in order to increase the concentration of ammonia and carbon dioxide. This is advantageous since this carbamate solution is fed to the urea synthesis device, where a low water input is advantageous for the reaction process.
  • the coarse process condensate purification device has a third heat exchanger.
  • the coarse process condensate purification device also has a recirculation line for a partial flow of the coarsely cleaned process condensate flow.
  • the third heat exchanger is arranged in the recirculation line and is designed to heat the recirculated partial flow.
  • this direct steam feed increases the amount of water in the coarsely cleaned process condensate stream.
  • the indirect heat input through a heat exchanger leaves the total quantity unchanged.
  • the partial flow can in particular also be evaporated.
  • the system network has a process condensate reservoir.
  • the process condensate reservoir is arranged after the urea synthesis device and before the process condensate purification device and the coarse process condensate purification device.
  • the coarse process condensate purification device and the urea synthesis device are connected via a first line for returning the in the coarse process condensate purification device resulting carbamate solution connected.
  • the process condensate purification device and the urea synthesis device are connected via a second output for recycling the carbamate solution emerging from the process condensate purification device.
  • the first line and the second line are connected to each other. In particular, these can flow into one another and be routed as a common line into the urea synthesis device.
  • the urea forming device has one or more fine waste air washing devices, for example droplet separation using a demister. Since this is the last cleaning step before the exhaust air is released into the environment, special cleanliness requirements are placed on the cleaning solution used. If this requirement is not met by the coarsely cleaned process condensate from the coarse process condensate cleaning device, a different source for the washing solution must be selected for this final cleaning step. Then, as before, the clean process condensate from the process condensate purification device is usually used. The amount of water in the fine exhaust air washing device is usually small compared to the total water requirement of the laundry. Therefore, the stated positive effects of the coarse process condensate purification device are also retained in this embodiment.
  • fine waste air washing devices for example droplet separation using a demister. Since this is the last cleaning step before the exhaust air is released into the environment, special cleanliness requirements are placed on the cleaning solution used. If this requirement is not met by the coarsely cleaned process condensate from the coarse process condensate cleaning device, a different source for
  • FIG. 1 shows a section of a system network. Ammonia and carbon dioxide are fed to the urea synthesis device 1 at the reactant inlet 30 and converted there to urea. The urea is then transferred to the urea forming device 2 . The exhaust air from the urea molding device 2 is transferred to the molding exhaust air washing device 4 .
  • the process condensate which is produced during the synthesis of urea from ammonia and carbon dioxide, is transferred from the urea synthesis device 1 to a process condensate store 3 .
  • the process condensate stream is divided according to the invention.
  • a partial flow for example 50%, is transferred to the process condensate purification device 10, as is known and customary from the prior art for such a plant network.
  • the process condensate is first fed through the fourth heat exchanger 14 into the first stage 11 and separated there at, for example, 140° C. and 3 bar of ammonia. After passing through the first stage 11, the process condensate reaches the second stage 12 through the fifth heat exchanger 15, for example for 60 minutes at 200° C. and 16 bar.
  • the urea is converted with water into ammonia and carbon dioxide.
  • the process condensate passes through the fifth heat exchanger 15 into the third stage 13, where ammonia is separated off under the same conditions as in the first stage 11 (in a common column). This then returns via a second line 41 to the urea synthesis device 1.
  • the cleaned process condensate passes from the third stage 13 through the fourth heat exchanger 14 to the process condensate outlet 32 and can be transferred to other processes.
  • Another partial flow, for example 50%, of the process condensate is transferred from the process condensate storage 3 into the coarse process condensate purification device 20 .
  • the process condensate first reaches the first heat exchanger 22 and is preheated there and transferred to the column 21, for example a packed column.
  • the gas stream emerging at the upper end of the column 21 is passed through the second heat exchanger 23 and condensed.
  • a partial flow thereof is fed back into the column 21 , and the remaining partial flow is fed through the first line 40 into the urea synthesis device 1 .
  • the coarsely cleaned process condensate exiting at the lower end of the column is divided and a partial flow is heated through the process condensate return line and the third heat exchanger 24 , at least partially evaporated, and fed back to the column 21 .
  • the rest Partial flow of the coarsely cleaned process condensate is routed via the first heat exchanger 22 to recover the heat and then routed into the forming exhaust air washing device 4 in order to take up more urea from the exhaust air there.

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Abstract

The invention relates to a combined system for producing a urea forming material. The combined system has at least one urea synthesizing device (1) and a urea forming device (2), and the combined system has a process condensate cleaning device (10), wherein the process condensate cleaning device (10) is designed to separate ammonia and urea from the process condensate of the urea synthesizing device (1), and the combined system has a formation exhaust air scrubbing device (4). The invention is characterized in that the combined system additionally has a coarse process condensate cleaning device (20) in addition to the process condensate cleaning device (10). The urea synthesizing device (1) is connected to the process condensate cleaning device (10) and the coarse process condensate cleaning device (20) in order to transfer process condensate, and the coarse process condensate cleaning device (20) is connected to the formation exhaust air scrubbing device (4).

Description

Optimierte Prozesskondensataufbereitung Optimized process condensate treatment
Die Erfindung betrifft die Aufbereitung des bei der Harnstoffsynthese anfallenden Prozesskondensats. The invention relates to the processing of the process condensate obtained in the urea synthesis.
Das in der Harnstoffsynthese anfallende Prozesskondensat enthält als Verunreinigungen sowohl Ammoniak als auch Harnstoff. Daher wird es vor einer weiteren Verwendung in einem dreistufigen Prozess gereinigt. In einem ersten Schritt wird bei Temperaturen oft um 115 bis 140 °C Ammoniak entfernt. Anschließen wird bei Temperaturen um 190 bis 200 °C und üblicherweise mehr als 15 bar und für eine Zeit von 60 bis 120 min eine Hydrolyse durchgeführt, bei der sich Harnstoff zu Ammoniak und Kohlendioxid zersetzt. Das entstehende Ammoniak und Kohlendioxid werden anschließend in einem dritten Schritt entfernt. Die Trennverfahren im ersten und dritten Schritt sind identisch, sodass diese beiden Schritte üblicherweise in einer Kolonne durchgeführt werden, die lediglich in der Mitte geteilt ist, um den zweiten Schritt zwischenzuschalten. The process condensate occurring in the urea synthesis contains both ammonia and urea as impurities. It is therefore cleaned in a three-stage process before it is used again. In a first step, ammonia is often removed at temperatures of around 115 to 140 °C. A hydrolysis is then carried out at temperatures of around 190 to 200° C. and usually more than 15 bar and for a time of 60 to 120 minutes, in which urea decomposes into ammonia and carbon dioxide. The resulting ammonia and carbon dioxide are then removed in a third step. The separation processes in the first and third step are identical, so these two steps are usually carried out in a column that is only split down the middle to interpose the second step.
Durch diesen dreistufigen Prozess wird der gesamte Prozesskondensatstrom sehr rein, insbesondere weniger als 3 ppm Ammoniak und weniger als 3 ppm Harnstoff. Dies ist entsprechend aufwändig und benötigt viel Energie. Es gibt insbesondere mit der für die Harnstoffformung, insbesondere Harnstoffgranulation oder Harnstoffprillierung, benötigte Abgaswäsche auch Anwendungen mit weniger hohe Reinheitsanforderungen, zumal dort Harnstoff als Verunreinigung aus dem Abgas eingebracht wird. This three-step process makes the entire process condensate stream very clean, specifically less than 3 ppm ammonia and less than 3 ppm urea. This is correspondingly complex and requires a lot of energy. There are also applications with less high purity requirements, especially with the exhaust gas scrubbing required for urea formation, in particular urea granulation or urea prilling, especially since urea is introduced there as an impurity from the exhaust gas.
Daher ist es energetisch vorteilhaft, für solche Abgaswäschen weniger aufgereinigtes Prozesskondensat zu verwenden. Die US 2019 / 0177180 A1 schlägt hierzu vor, einen Teilstrom nach der ersten Stufe abzutrennen und der Abgaswäsche zuzuführen. Dieses führt aber dazu, dass die Ströme in der ersten Stufe und der dritten Stufe, welche sich in einer gemeinsamen Kolonne befinden, sehr unterschiedliche Mengen aufweisen, was sich als nachteilig auf die Auslegung und den Betrieb auswirken kann. It is therefore energetically advantageous to use less purified process condensate for such exhaust gas scrubbing. US 2019 / 0177180 A1 proposes separating a partial flow after the first stage and feeding it to the exhaust gas scrubber. However, this means that the streams in the first stage and the third stage, which are in a common column, have very different amounts, which can have a disadvantageous effect on the design and operation.
Aus der US 4 652 678 A ist ein Verfahren zur Rückgewinnung wertvoller Komponenten aus einem Abgasstrom der Harnstoffsynthese bekannt. i Aus der US 4 410 503 A ist ein Verfahren zur Entfernung von Harnstoff, Ammoniak und Kohlendioxid aus einer verdünnten wässrigen Lösung bekannt. US Pat. No. 4,652,678 A discloses a method for recovering valuable components from a waste gas stream from urea synthesis. i A method for removing urea, ammonia and carbon dioxide from a dilute aqueous solution is known from US Pat. No. 4,410,503 A.
Aufgabe der Erfindung ist es, eine Prozesskondensataufbereitung bereitzustellen, welche zum einen die hohe Reinheit für die üblichen Verwendungen als auch eine geringere Reinheit für die Abgaswäsche aufweist und dabei eine optimale Prozessführung bei minimalen Energieverbrauch ermöglicht. The object of the invention is to provide a process condensate treatment which, on the one hand, has the high purity for the usual uses and, on the other hand, has a lower purity for the waste gas scrubbing, and at the same time enables optimal process management with minimal energy consumption.
Gelöst wird diese Aufgabe durch den Anlagenverbund mit den in Anspruch 1 angegebenen Merkmalen. Vorteilhafte Weiterbildungen ergeben sich aus den Unteransprüchen, der nachfolgenden Beschreibung sowie der Zeichnung. This problem is solved by the system network with the features specified in claim 1 . Advantageous developments result from the dependent claims, the following description and the drawing.
Der erfindungsgemäße Anlagenverbund dient zur Herstellung eines Harnstoffformmaterials, insbesondere eines Harnstoffgranulats oder eines Harnstoffprills. Es werden üblicherweise die Begriffe Granulat oder Prill verwendet, es handelt sich um partikuläres, agglomeriertes Material, welches eine für die Aufbringung als Düngemittel geeignete Partikelgröße aufweist und üblicherweise in einen sich an die Synthese anschließenden Formungsschritt, der Granulation oder Prillierung, hergestellt wird. Der Anlagenverbund weist wenigstens eine Harnstoffsynthesevorrichtung und eine Harnstoffformungsvorrichtung auf. Üblicherweise weist der Anlagenverbund zusätzlich auch eine Vorrichtung zur Synthese von Ammoniak und in vielen Fällen einen Reformer zur Herstellung des Wasserstoffs auf. Aus Wasserstoff und Stickstoff wird in der Vorrichtung zur Synthese von Ammoniak Ammoniak hergestellt. Aus diesem Ammoniak wird mit Kohlendioxid in der Harnstoffsynthesevorrichtung Harnstoff hergestellt und teilweise mit weiteren Komponenten, beispielsweise Ammoniumnitrat, Schwefelverbindungen, Kalk und dergleichen mehr, in der Harnstoffformungsvorrichtung zu einem Granulat verarbeitet, welches insbesondere als Düngemittel breite Verwendung findet. Der Anlagenverbund kann optional auch eine Salperersäuresynthesevorrichtung und optional zusätzlich eine Ammoniumnitratsynthesevorrichtung aufweisen. In diesem Fall kann beispielsweise Ammoniumnitrat als weitere Komponente mit dem Harnstoff gemischt und gemeinsam geformt, insbesondere granuliert, werden. Der Anlagenverbund weist eine Prozesskondensataufreinigungsvorrichtung auf, wobei die Prozesskondensataufreinigungsvorrichtung zur Abtrennung von Ammoniak und Harnstoff aus dem Prozesskondensat der Harnstoffsynthesevorrichtung ausgebildet ist. Hierdurch wird eine weitere Verwendung des Wassers innerhalb oder außerhalb des Anlagenverbunds oder auch dessen Entsorgung ermöglicht. Die Prozesskondensataufreinigungsvorrichtung weist einen Aufreinigungsstrom bis zum Prozesskondensatausgang auf. Der Aufreinigungsstrom führt das Prozesskondensat durch üblicherweise drei Stufen, um eine hohe Reinheit des Prozesskondensatats zu erreichen, Dadurch kann das aufgereinigte Prozesskondensat vielfältig verwendet werden. Der Anlagenverbund weist eine Formungsabluftwäschevorrichtung auf, die mit der Harnstoffformungsvorrichtung verbunden ist und zur Reinigung der Abgase dieser dient. Die Formungsabluftwäschevorrichtung dient dazu, den in die Abluft gelangten Harnstoff durch Auswaschen mit Wasser zu entfernen und so die Emission von Stickstoff zu reduzieren. Oft weist die Formungsabluftwäschevorrichtung eine zweite Stufe auf, in der eine Wäsche mit einem sauren Medium Ammoniak entfernt. The system network according to the invention serves to produce a urea molding material, in particular urea granules or urea prills. The terms granulate or prill are usually used; they are particulate, agglomerated material which has a particle size suitable for application as a fertilizer and is usually produced in a shaping step following the synthesis, ie granulation or prilling. The plant network has at least one urea synthesis device and one urea forming device. The plant network usually also has a device for synthesizing ammonia and, in many cases, a reformer for producing the hydrogen. Ammonia is produced from hydrogen and nitrogen in the device for the synthesis of ammonia. From this ammonia, urea is produced with carbon dioxide in the urea synthesis device and partly processed with other components, for example ammonium nitrate, sulfur compounds, lime and the like, in the urea forming device to form granules which are widely used in particular as fertilizers. The plant network can optionally also have a nitric acid synthesis device and optionally also an ammonium nitrate synthesis device. In this case, ammonium nitrate, for example, can be mixed with the urea as a further component and shaped together, in particular granulated. The plant network has a process condensate purification device, wherein the process condensate purification device for separating ammonia and Urea is formed from the process condensate of the urea synthesis device. This enables further use of the water inside or outside of the system network or its disposal. The process condensate purification device has a purification flow up to the process condensate outlet. The purification stream usually leads the process condensate through three stages in order to achieve a high degree of purity of the process condensate. This means that the purified process condensate can be used in a variety of ways. The plant network has a shaping exhaust air washing device, which is connected to the urea shaping device and is used to clean the exhaust gases of this device. The molding exhaust air washing device serves to remove the urea that has gotten into the exhaust air by washing it out with water, thus reducing the emission of nitrogen. Often the forming effluent scrubber includes a second stage in which a scrub with an acidic medium removes ammonia.
Erfindungsgemäß weist der Anlagenverbund zusätzlich zur Prozesskondensataufreinigungsvorrichtung eine Grobprozesskondensataufreinigungsvorrichtung auf. Die Grobprozesskondensataufreinigungsvorrichtung weist einen Grobreinigungsstrom auf. Im Grobreinigungsstrom erfolgte eine einfachere Aufreinigung im Vergleich zur Prozesskondensataufreinigungsvorrichtung, sodass das grob aufgereinigte Prozesskondensat eine geringere Reinheit aufweist, wobei aber die für die Grobaufreinigung benötigte Aufwand entsprechend reduziert ist. Der Grobreinigungsstrom ist von dem Aufreinigungsstrom getrennt und verschieden. Die Grobprozesskondensataufreinigungsvorrichtung und die Prozesskondensataufreinigungsvorrichtung sind somit zwei getrennte Vorrichtungen und die Grobprozesskondensataufreinigungsvorrichtung ist eben nicht nur beispielsweise die erste Stufe der Prozesskondensataufreinigungsvorrichtung. Die Harnstoffsynthesevorrichtung ist mit der Prozesskondensataufreinigungsvorrichtung und der Grobprozesskondensataufreinigungsvorrichtung zur Überführung von Prozesskondensat verbunden. Die Grobprozesskondensataufreinigungsvorrichtung ist mit derAccording to the invention, the plant network has a coarse process condensate purification device in addition to the process condensate purification device. The coarse process condensate purification device has a coarse purification stream. In the coarse purification flow, a simpler purification took place compared to the process condensate purification device, so that the roughly purified process condensate has a lower purity, but the effort required for the coarse purification is correspondingly reduced. The coarse purification stream is separate and distinct from the purification stream. The coarse process condensate purification device and the process condensate purification device are thus two separate devices and the coarse process condensate purification device is not just, for example, the first stage of the process condensate purification device. The urea synthesis device is connected to the process condensate purification device and the coarse process condensate purification device for transferring process condensate. The coarse process condensate purification device is equipped with the
Formungsabluftwäschevorrichtung verbunden. Somit wird erfindungsgemäß der Strom des Prozesskondensats der Harnstoffsynthesevorrichtung in zwei Teilströme geteilt. Ein erster Teilstrom geht in die Prozesskondensataufreinigungsvorrichtung nach dem Stand der Technik. Da dieser Strom vollständig gereinigt wird, sind die erste Stufe und die dritte Stufe für den gleichen Volumenstrom ausgelegt und werden auch so betrieben. Parallel zur herkömmlichen Prozesskondensataufreinigungsvorrichtung ist die neue Grobprozesskondensataufreinigungsvorrichtung angeordnet, in die ein zweiter Teilstrom geführt wird. Je nach Umgebungsbedingungen kann beispielsweise der Bedarf an dem ersten Teilstrom und dem zweiten Teilstrom in etwa gleich groß sein. Der für die Formungsabluftwäschevorrichtung, beispielsweise der Granulation oder der Prillierung, benötigte Wasserstrom wird in der Grobprozesskondensataufreinigungsvorrichtung nur für diese Anwendung ausreichend und damit sehr viel energiesparender gereinigt. Eine Entfernung des Harnstoffs aus dem Prozesskondensat ist für dessen Verwendung in der Abluftwäsche nicht notwendig. Insbesondere weist die Grobprozesskondensataufreinigungsvorrichtung nur eine Stufe und damit vor allem keine Hydrolyse in einem zweiten Schritt auf. Die Menge an Ammoniak im Prozesskondensat kann durch den separaten Grobprozesskondensataufreinigungsvorrichtung gezielt eingestellt werden. Nach Stand der Technik wird das in der Formung, insbesondere der Granulation beziehungsweise der Prillierung, freigesetzte Ammoniak aus der Abluft vorzugsweise durch eine saure Wäsche, zum Beispiel mit Salpetersäure oder Schwefelsäure, entfernt. Dabei entsteht abhängig von der eingesetzten Säure das dazugehörige Ammoniaksalz, welches ebenfalls als Düngermittel oder als Einsatzstoff für weitere Prozesse, zum Beispiel für die Herstellung von Harnstoff-Ammoniumnitrat (UAN), genutzt werden kann. Das nach der Grobprozesskondensataufreinigungsvorrichtung im für die Abluftwäsche genutzten Prozesskondensatstrom verbleibende Ammoniak wird in der sauren Waschstufe der Abluftwäsche ausgewaschen. Nach dem Stand der Technik wird die für die Prozesskondensataufreinigungsvorrichtung benötigte Wärmemenge in Form von Dampf bereitgestellt, der überwiegend direkt in den Prozess eingespeist und somit selbst zum Prozesskondensat wird. Findet die Prozesskondensataufreinigung energiesparender statt, kann diese Menge an eingespeisten Dampf reduziert werden. Dies führt zu einer Reduktion der anfallenden Prozesskondensatmenge, da durch den eingesparten Dampf kein zusätzliches Wasser eingetragen wird, welches die Prozesskondensatmenge steigern würde. Forming effluent scrubber connected. Thus, according to the invention, the flow of the process condensate of the urea synthesis device is divided into two partial flows. A first partial flow goes into the prior art process condensate purification device. Since this stream is completely purified, the first stage and the third Stage designed for the same volume flow and are also operated in this way. The new coarse process condensate purification device, into which a second partial flow is fed, is arranged parallel to the conventional process condensate purification device. Depending on the environmental conditions, the need for the first partial flow and the second partial flow can be approximately the same, for example. The water flow required for the forming exhaust air washing device, for example granulation or prilling, is cleaned sufficiently in the coarse process condensate cleaning device only for this application and is therefore much more energy-efficient. A removal of the urea from the process condensate is not necessary for its use in the exhaust air scrubber. In particular, the coarse process condensate purification device has only one stage and therefore, above all, no hydrolysis in a second step. The amount of ammonia in the process condensate can be specifically adjusted by the separate coarse process condensate purification device. According to the prior art, the ammonia released from the exhaust air during the forming process, in particular during the granulation or prilling process, is preferably removed by acidic scrubbing, for example with nitric acid or sulfuric acid. Depending on the acid used, the associated ammonia salt is formed, which can also be used as a fertilizer or as a feedstock for other processes, for example for the production of urea ammonium nitrate (UAN). The ammonia remaining after the coarse process condensate cleaning device in the process condensate stream used for the exhaust air scrubbing is washed out in the acidic washing stage of the exhaust air scrubbing. According to the prior art, the amount of heat required for the process condensate purification device is provided in the form of steam, which is predominantly fed directly into the process and is thus itself the process condensate. If the process condensate cleaning takes place more energy-efficiently, this amount of steam fed in can be reduced. This leads to a reduction in the amount of process condensate that occurs, since the saved steam means that no additional water is introduced, which would increase the amount of process condensate.
Durch die strikte Trennung der Prozesskondensataufreinigungsvorrichtung und des Aufreinigungsstroms von der Grobprozesskondensataufreinigungsvorrichtung und des Grobreinigungsstroms ergeben sich zwei grundlegende Vorteile. Der erste Vorteil ist, dass insbesondere die Prozesskondensataufreinigungsvorrichtung für einen konstanten durchlaufenden Aufreinigungsstrom ausgelegt ist. Somit sind alle Stufen für einen identischen Volumenstrom ausgelegt, was vorteilhaft ist. Der zweite Vorteil ist, dass somit eine Nachrüstung im Rahmen einer Kapazitätserweiterung leicht möglich ist. Wird beispielsweise ein entsprechender bestehender Anlagenverbund so umgerüstet, dass die Produktionskapazität erweitert wird, so kann eine bestehende Prozesskondensataufreinigungsvorrichtung weiter betrieben werden und zusätzlich wird eine neue zusätzliche und getrennte Grobprozesskondensataufreinigungsvorrichtung installiert, die den durch die Kapazitätserweiterung hinzugekommenen Prozesskondensatstrom in einfacher und reduzierter Weise reinigt und für entsprechende Anwendungen, insbesondere die Formungsabluftwäschevorrichtung zur Verfügung stellt. Somit kann auf eine Kapazitätserweiterung der Prozesskondensataufreinigungsvorrichtung in vorteilhafter Weise verzichtet werden. The strict separation of the process condensate purification device and the purification flow from the coarse process condensate purification device and the coarse purification flow results in two fundamental advantages. The first benefit is that in particular the process condensate purification device is designed for a constant continuous purification stream. All stages are therefore designed for an identical volume flow, which is advantageous. The second advantage is that retrofitting as part of a capacity expansion is easily possible. If, for example, a corresponding existing plant network is converted in such a way that the production capacity is expanded, an existing process condensate purification device can continue to be operated and a new, additional and separate coarse process condensate purification device is installed, which cleans the process condensate flow added by the capacity expansion in a simple and reduced manner and for corresponding Applications, in particular the forming exhaust air scrubber provides. A capacity expansion of the process condensate purification device can thus advantageously be dispensed with.
In einer weiteren Ausführungsform der Erfindung ist die Grobprozesskondensataufreinigungsvorrichtung einstufig zur Entfernung von Ammoniak ausgebildet. Insbesondere ist die Grobprozesskondensataufreinigungsvorrichtung in Form einer Kolonne, insbesondere einer Bodenkolonne oder einer Füllkörperkolonne, ausgebildet. Eine zweite Stufe zur Hydrolyse von Harnstoff zu Ammoniak und CO2 ist somit bevorzugt eben nicht Bestandteil der Grobprozesskondensataufreinigungsvorrichtung. In a further embodiment of the invention, the coarse process condensate purification device is designed in one stage for the removal of ammonia. In particular, the coarse process condensate purification device is designed in the form of a column, in particular a tray column or a packed column. A second stage for the hydrolysis of urea to form ammonia and CO2 is therefore preferably not part of the coarse process condensate purification device.
In einer weiteren Ausführungsform der Erfindung weist die Grobprozesskondensataufreinigungsvorrichtung einen ersten Wärmetauscher auf. Der erste Wärmetauscher ist zur Vorwärmung des von der Harnstoffsynthesevorrichtung kommenden Prozesskondensatestroms ausgebildet. Dieses erfolgt dadurch, dass der Wärmetauscher zur Abkühlung des aus der Grobprozesskondensataufreinigungsvorrichtung austretenden grobgereinigten Prozesskondensatestroms ausgebildet ist. Somit kann die Prozesswärme in der Grobprozesskondensataufreinigungsvorrichtung gehalten werden. In a further embodiment of the invention, the coarse process condensate purification device has a first heat exchanger. The first heat exchanger is designed to preheat the process condensate stream coming from the urea synthesis device. This takes place in that the heat exchanger is designed to cool the coarsely cleaned process condensate flow emerging from the coarse process condensate purification device. The process heat can thus be kept in the coarse process condensate purification device.
In einer weiteren Ausführungsform der Erfindung weist die Grobprozesskondensataufreinigungsvorrichtung einen zweiten Wärmetauscher auf. Der zweite Wärmetauscher ist zur Kondensation des aus der Grobprozesskondensataufreinigungsvorrichtung austretenden Gasstromes ausgebildet. Insbesondere kann hier das Gasgemisch, welches insbesondere Wasser, Ammoniak und Kohlendioxid enthält, kondensiert werden. Dieses Prozesskondensat kann auch als Carbamatlösung bezeichnet werden, da das dort enthaltene Ammoniak und Kohlendioxid in wässriger Lösung teilweise miteinander reagieren, unter anderem zu Carbamat. Bevorzugt sind der zweite Wärmetauscher und die Grobprozesskondensataufreinigungsvorrichtung mit einer Carbamatrückführungsleitung verbunden. Hierdurch kann ein Teilstrom der Carbamatlösung zurück in die Grobprozesskondensataufreinigungsvorrichtung geführt werden. Mit dieser Rückführung kann der Wasseranteil in der Carbamatlösung bei Bedarf reduziert werden um die Konzentration an Ammoniak und Kohlendioxid zu steigern. Dies ist vorteilhaft, da diese Carbamatlösung der Harnstoffsynthesevorrichtung zugeführt wird, wo ein geringer Wassereintrag vorteilhaft für die Reaktionsführung ist. In a further embodiment of the invention, the coarse process condensate purification device has a second heat exchanger. The second heat exchanger is designed to condense the gas stream exiting the coarse process condensate purification device. In particular, the gas mixture can which contains in particular water, ammonia and carbon dioxide, are condensed. This process condensate can also be referred to as a carbamate solution, since the ammonia and carbon dioxide contained there partially react with one another in an aqueous solution, to form carbamate, among other things. The second heat exchanger and the coarse process condensate purification device are preferably connected to a carbamate return line. As a result, a partial flow of the carbamate solution can be fed back into the coarse process condensate purification device. With this recirculation, the proportion of water in the carbamate solution can be reduced if necessary in order to increase the concentration of ammonia and carbon dioxide. This is advantageous since this carbamate solution is fed to the urea synthesis device, where a low water input is advantageous for the reaction process.
In einer weiteren Ausführungsform der Erfindung weist die Grobprozesskondensataufreinigungsvorrichtung einen dritten Wärmetauscher auf. Die Grobprozesskondensataufreinigungsvorrichtung weist weiter eine Rezirkulationsleitung für einen Teilstrom des grobgereinigten Prozesskondensatestroms auf. Der dritte Wärmetauscher ist in der Rezirkulationsleitung angeordnet und zur Erwärmung des rezirkulierten Teilstroms ausgebildet. Um die benötigte Wärme der Grobprozesskondensataufreinigungsvorrichtung zuzuführen, könnte man alternativ auch Dampf direkt einleiten. Diese Dampfdirekteinspeisung erhöht aber die Wassermenge des grobgereinigten Prozesskondensatestroms. Die indirekte Wärmeeinbringung durch einen Wärmetauscher lässt die Gesamtmenge jedoch unverändert. In dem dritten Wärmetauscher oder dem nachgelagert, beispielsweise nach einem entsprechenden Druckventil, kann insbesondere auch eine Verdampfung des Teilstroms erfolgen. In a further embodiment of the invention, the coarse process condensate purification device has a third heat exchanger. The coarse process condensate purification device also has a recirculation line for a partial flow of the coarsely cleaned process condensate flow. The third heat exchanger is arranged in the recirculation line and is designed to heat the recirculated partial flow. In order to supply the required heat to the coarse process condensate purification device, one could alternatively also introduce steam directly. However, this direct steam feed increases the amount of water in the coarsely cleaned process condensate stream. However, the indirect heat input through a heat exchanger leaves the total quantity unchanged. In the third heat exchanger or downstream, for example after a corresponding pressure valve, the partial flow can in particular also be evaporated.
In einer weiteren Ausführungsform der Erfindung weist der Anlagenverbund ein Prozesskondensatspeicher auf. Der Prozesskondensatspeicher ist nach der Harnstoff- synthesevorrichtung und vor der Prozesskondensataufreinigungsvorrichtung und der Grobprozesskondensataufreinigungsvorrichtung angeordnet. In a further embodiment of the invention, the system network has a process condensate reservoir. The process condensate reservoir is arranged after the urea synthesis device and before the process condensate purification device and the coarse process condensate purification device.
In einer weiteren Ausführungsform der Erfindung sind die Grobprozesskondensataufreinigungsvorrichtung und die Harnstoffsynthesevorrichtung über eine erste Leitung zur Rückführung des in der Grobprozesskondensataufreinigungsvorrichtung entstehenden Carbamatlösung verbunden. Insbesondere sind die Prozesskondensataufreinigungsvorrichtung und die Harnstoffsynthesevorrichtung über eine zweite Leistung zur Rückführung des aus der Prozesskondensataufreinigungsvorrichtung austretenden Carbamatlösung verbunden. Die erste Leitung und die zweite Leitung sind miteinander verbunden. Insbesondere können diese ineinander münden und als eine gemeinsame Leitung in die Harnstoffsynthesevorrichtung geführt werden. In a further embodiment of the invention, the coarse process condensate purification device and the urea synthesis device are connected via a first line for returning the in the coarse process condensate purification device resulting carbamate solution connected. In particular, the process condensate purification device and the urea synthesis device are connected via a second output for recycling the carbamate solution emerging from the process condensate purification device. The first line and the second line are connected to each other. In particular, these can flow into one another and be routed as a common line into the urea synthesis device.
In einer weiteren Ausführungsform der Erfindung weist die Harnstoffformungsvorrichtung eine oder mehrere Feinabluftwäschevorrichtung auf, beispielsweise eine Tropfenabscheidung mittels eines Demisters. Da dies der letzte Reinigungsschritt vor Abgabe der Abluft an die Umgebung ist, werden an die dabei verwendete Waschlösung besondere Reinheitsanforderungen gestellt. Falls diese Anforderung vom grobgereinigten Prozesskondensat aus der Grobprozesskondensataufreinigungsvorrichtung nicht erfüllt wird, muss für diesen letzten Reinigungsschritt eine andere Quelle für die Waschlösung gewählt werden. Üblicherweise wird dann wie zuvor bereits das saubere Prozesskondensat aus der Prozesskondensataufreinigungsvorrichtung verwendet. Die Wassermenge der Feinabluftwäschevorrichtung ist üblicherweise klein im Vergleich zum Gesamtwasserbedarf der Wäsche. Daher bleiben die aufgeführten positiven Effekte der Grobprozesskondensataufreinigungsvorrichtung auch in dieser Ausführungsform erhalten. In a further embodiment of the invention, the urea forming device has one or more fine waste air washing devices, for example droplet separation using a demister. Since this is the last cleaning step before the exhaust air is released into the environment, special cleanliness requirements are placed on the cleaning solution used. If this requirement is not met by the coarsely cleaned process condensate from the coarse process condensate cleaning device, a different source for the washing solution must be selected for this final cleaning step. Then, as before, the clean process condensate from the process condensate purification device is usually used. The amount of water in the fine exhaust air washing device is usually small compared to the total water requirement of the laundry. Therefore, the stated positive effects of the coarse process condensate purification device are also retained in this embodiment.
Nachfolgend ist der erfindungsgemäße Anlagenverbund anhand eines in der Zeichnung dargestellten Ausführungsbeispiels näher erläutert. The plant network according to the invention is explained in more detail below with reference to an exemplary embodiment illustrated in the drawing.
Fig. 1 beispielhafte Ausführungsform 1 exemplary embodiment
Die Darstellung ist rein schematisch und stark vereinfacht zur Verdeutlichung der Erfindung. Übliche Komponenten, wie zum Beispiel Ventile, Wärmetauscher, Fördervorrichtungen, wie zum Beispiel Pumpen und dergleichen sind zur Vereinfachung weggelassen und sind dem Fachmann für solche Anlagen ausreichend bekannt. Ziel der Darstellung ist es, den erfindungsgemäßen Gedanken zu verdeutlichen. In Fig. 1 ist ein Ausschnitt eines Anlagenverbunds gezeigt. Ammoniak und Kohlendioxid werden am Edukteingang 30 der Harnstoffsynthesevorrichtung 1 zugeführt und dort zu Harnstoff umgesetzt. Der Harnstoff wird dann in die Harnstoffformungsvorrichtung 2 überführt. Die Abluft aus der Hamstoffformungsvorrichtung 2 wird in die Formungsabluftwäschevorrichtung 4 überführt. Das Prozesskondensat, welches bei der Synthese von Harnstoff aus Ammoniak und Kohlendioxid entsteht, wird aus der Harnstoffsynthesevorrichtung 1 in einen Prozesskondensatspeicher 3 überführt. Hier wird der Prozesskondensatstrom erfindungsgemäß aufgeteilt. Ein Teilstrom, beispielsweise 50 %, werden in die Prozesskondensataufreinigungsvorrichtung 10 überführt, wie diese aus dem Stand der Technik für einen solchen Anlagenverbund bekannt und üblich ist. Das Prozesskondensat wird zunächst durch den vierten Wärmetauscher 14 in die erste Stufe 11 geführt und dort bei zum Beispiel 140 °C und 3 bar Ammoniak abgetrennt. Nach dem Durchlaufen der ersten Stufe 11 gelangt das Prozesskondensat durch den fünften Wärmetauscher 15 in die zweite Stufe 12, beispielswiese für 60 min bei 200 °C und 16 bar. Hierdurch wird der Harnstoff mit Wasser in Ammoniak und Kohlendioxid umgesetzt. Durch den fünften Wärmetauscher 15 gelangt das Prozesskondensat in die dritte Stufe 13, wo bei den gleichen Bedingungen der ersten Stufe 11 (in einer gemeinsamen Kolonne) Ammoniak abgetrennt wird. Dieses gelangt dann über eine zweite Leitung 41 zurück in die Harnstoffsynthesevorrichtung 1. Das gereinigte Prozesskondensat gelangt aus der dritten Stufe 13 durch den vierten Wärmetauscher 14 zum Prozesskondensatausgang 32 und kann an andere Prozesse übergeben werden. The representation is purely schematic and greatly simplified to clarify the invention. Customary components such as valves, heat exchangers, conveying devices such as pumps and the like have been omitted for the sake of simplicity and are sufficiently known to those skilled in the art for such systems. The aim of the presentation is to clarify the idea according to the invention. 1 shows a section of a system network. Ammonia and carbon dioxide are fed to the urea synthesis device 1 at the reactant inlet 30 and converted there to urea. The urea is then transferred to the urea forming device 2 . The exhaust air from the urea molding device 2 is transferred to the molding exhaust air washing device 4 . The process condensate, which is produced during the synthesis of urea from ammonia and carbon dioxide, is transferred from the urea synthesis device 1 to a process condensate store 3 . Here the process condensate stream is divided according to the invention. A partial flow, for example 50%, is transferred to the process condensate purification device 10, as is known and customary from the prior art for such a plant network. The process condensate is first fed through the fourth heat exchanger 14 into the first stage 11 and separated there at, for example, 140° C. and 3 bar of ammonia. After passing through the first stage 11, the process condensate reaches the second stage 12 through the fifth heat exchanger 15, for example for 60 minutes at 200° C. and 16 bar. As a result, the urea is converted with water into ammonia and carbon dioxide. The process condensate passes through the fifth heat exchanger 15 into the third stage 13, where ammonia is separated off under the same conditions as in the first stage 11 (in a common column). This then returns via a second line 41 to the urea synthesis device 1. The cleaned process condensate passes from the third stage 13 through the fourth heat exchanger 14 to the process condensate outlet 32 and can be transferred to other processes.
Ein weiterer Teilstrom, beispielsweise 50 %, des Prozesskondensats werden aus dem Prozesskondensatspeicher 3 in die Grobprozesskondensataufreinigungsvorrichtung 20 überführt. Dort gelangt das Prozesskondensat zunächst in den ersten Wärmetauscher 22 und wird dort vorgewärmt und in die Kolonne 21 , beispielsweise eine Füllkörperkolonne, überführt. Der am oberen Ende der Kolonne 21 austretende Gasstrom wird durch den zweiten Wärmetauscher 23 geleitet und kondensiert. Ein Teilstrom davon wird zurück in die Kolonne 21 geführt, der restliche Teilstrom durch die erste Leitung 40 in die Harnstoffsynthesevorrichtung 1 geführt. Das am unteren Ende der Kolonne austretende grobgereinigte Prozesskondensat wird geteilt und ein Teilstrom durch die Prozesskondensatrückführungsleitung und den dritten Wärmetauscher 24 erwärmt, zumindest teilweise verdampft, und erneut der Kolonne 21 zugeführt. Der restliche Teilstrom des grobgereinigten Prozesskondensats wird über den ersten Wärmetauscher 22 zur Rückgewinnung der Wärme geführt und anschließend in die Formungsabluftwäschevorrichtung 4 geführt, um dort weiteren Harnstoff aus der Abluft aufzunehmen. Another partial flow, for example 50%, of the process condensate is transferred from the process condensate storage 3 into the coarse process condensate purification device 20 . There, the process condensate first reaches the first heat exchanger 22 and is preheated there and transferred to the column 21, for example a packed column. The gas stream emerging at the upper end of the column 21 is passed through the second heat exchanger 23 and condensed. A partial flow thereof is fed back into the column 21 , and the remaining partial flow is fed through the first line 40 into the urea synthesis device 1 . The coarsely cleaned process condensate exiting at the lower end of the column is divided and a partial flow is heated through the process condensate return line and the third heat exchanger 24 , at least partially evaporated, and fed back to the column 21 . the rest Partial flow of the coarsely cleaned process condensate is routed via the first heat exchanger 22 to recover the heat and then routed into the forming exhaust air washing device 4 in order to take up more urea from the exhaust air there.
Bezugszeichen Reference sign
1 Harnstoffsynthesevorrichtung 1 urea synthesizer
2 Harnstoffformungsvorrichtung 2 urea forming device
3 Prozesskondensatspeicher 3 process condensate storage
4 Formungsabluftwäschevorrichtung 4 Forming effluent scrubber
10 Prozesskondensataufreinigungsvorrichtung 10 process condensate purification device
11 erste Stufe 11 first stage
12 zweite Stufe 12 second stage
13 dritte Stufe 13 third stage
14 vierter Wärmetauscher 14 fourth heat exchanger
15 fünfter Wärmetauscher 15 fifth heat exchanger
20 Grobprozesskondensataufreinigungsvorrichtung 20 coarse process condensate purification device
21 Kolonne 21 column
22 erster Wärmetauscher 22 first heat exchanger
23 zweiter Wärmetauscher 23 second heat exchanger
24 dritter Wärmetauscher 24 third heat exchanger
30 Edukteingang 30 educt input
31 Produktausgang 31 product exit
32 Prozesskondensatausgang 32 process condensate outlet
40 erste Leitung 40 first line
41 zweite Leitung 41 second line

Claims

Patentansprüche patent claims
1. Anlagenverbund zur Herstellung eines Harnstoffformmatenals, wobei der Anlagenverbund wenigstens eine Harnstoffsynthesevorrichtung (1) und eine Harnstoffformungsvorrichtung (2) aufweist, wobei der Anlagenverbund eine Prozesskondensataufreinigungsvorrichtung (10) aufweist, wobei die Prozesskondensataufreinigungsvorrichtung (10) zur Abtrennung von Ammoniak und Harnstoff aus dem Prozesskondensat der Harnstoffsynthesevorrichtung (1 ) ausgebildet ist, wobei die Prozesskondensataufreinigungsvorrichtung (10) einen Aufreinigungsstrom bis zum Prozesskondensatausgang (32) aufweist, wobei der Anlagenverbund eine Formungsabluftwäschevorrichtung(4) aufweist, dadurch gekennzeichnet, dass der Anlagenverbund zusätzlich zur Prozesskondensataufreinigungsvorrichtung (10) eine Grobprozesskondensataufreinigungsvorrichtung (20) aufweist, wobei die Grobprozesskondensataufreinigungsvorrichtung (20) einen Grobreinigungsstrom aufweist, wobei der Grobreinigungsstrom von dem Aufreinigungsstrom getrennt und verschieden ist, wobei die Harnstoffsynthesevorrichtung (1 ) mit der Prozesskondensataufreinigungsvorrichtung (10) und der Grobprozesskondensataufreinigungsvorrichtung (20) zur Überführung von Prozesskondensat verbunden ist, wobei die Grobprozesskondensataufreinigungsvorrichtung (20) mit der Formungsabluftwäschevorrichtung (4) verbunden ist. 1. Plant network for producing a urea form material, the plant network having at least one urea synthesis device (1) and one urea forming device (2), the plant network having a process condensate purification device (10), the process condensate purification device (10) for separating ammonia and urea from the process condensate of the urea synthesis device (1), wherein the process condensate purification device (10) has a purification stream up to the process condensate outlet (32), wherein the plant network has a molding waste air washing device (4), characterized in that the plant network has, in addition to the process condensate purification device (10), a coarse process condensate purification device (20 ), wherein the coarse process condensate purification device (20) has a coarse purification stream, wherein the coarse purification stream is separate and different from the purification stream, wherein the urea synthesis device (1) is connected to the process condensate purification device (10) and the coarse process condensate purification device (20) for the transfer of process condensate, wherein the coarse process condensate purification device (20) is connected to the forming exhaust air washing device (4).
2. Anlagenverbund nach Anspruch 1 , dadurch gekennzeichnet, dass die Grobprozesskondensataufreinigungsvorrichtung (20) einstufig zur Entfernung von Ammoniak ausgebildet ist. 2. Plant network according to claim 1, characterized in that the coarse process condensate purification device (20) is designed in one stage for the removal of ammonia.
3. Anlagenverbund nach einem der vorstehenden Ansprüche, dadurch gekennzeichnet, dass die Grobprozesskondensataufreinigungsvorrichtung (20) einen ersten Wärmetauscher (22) aufweist, wobei der erste Wärmetauscher (22) zur Vorwärmung des von der Harnstoffsynthesevorrichtung (1 ) kommenden Prozesskondensatestroms ausgebildet ist, wobei der erste Wärmetauscher (22) zur Abkühlung des aus der Grobprozesskondensataufreinigungsvorrichtung (20) austretenden grobgereinigten Prozesskondensatestroms ausgebildet ist. io 3. Plant network according to one of the preceding claims, characterized in that the coarse process condensate purification device (20) has a first heat exchanger (22), the first heat exchanger (22) being designed to preheat the process condensate stream coming from the urea synthesis device (1), the first Heat exchanger (22) for cooling the coarse process condensate purification device (20) exiting the coarsely cleaned process condensate stream is formed. ok
4. Anlagenverbund nach einem der vorstehenden Ansprüche, dadurch gekennzeichnet, dass die Grobprozesskondensataufreinigungsvorrichtung (20) einen zweiten Wärmetauscher (23) aufweist, wobei der zweite Wärmetauscher (23) zur Kondensation des aus der4. Plant network according to one of the preceding claims, characterized in that the coarse process condensate purification device (20) has a second heat exchanger (23), wherein the second heat exchanger (23) for the condensation of the
Grobprozesskondensataufreinigungsvorrichtung (20) austretenden Gasstromes ausgebildet ist. Coarse process condensate purification device (20) exiting gas stream is formed.
5. Anlagenverbund nach Anspruch 4, dadurch gekennzeichnet, dass der zweite Wärmetauscher (23) und die Grobprozesskondensataufreinigungsvorrichtung (20) mit einer Carbamatrückführungsleitung verbunden sind. 5. Plant network according to claim 4, characterized in that the second heat exchanger (23) and the coarse process condensate purification device (20) are connected to a carbamate return line.
6. Anlagenverbund nach einem der vorstehenden Ansprüche, dadurch gekennzeichnet, dass die Grobprozesskondensataufreinigungsvorrichtung (20) einen dritten Wärmetauscher (24) aufweist, wobei die Grobprozesskondensataufreinigungsvorrichtung (20) eine Rezirkulationsleitung für einen Teilstrom des grobgereinigten Prozesskondensatestroms aufweist, wobei der dritte Wärmetauscher (24) in der Rezirkulationsleitung zur Erwärmung des rezikulierten Teilstroms ausgebildet ist. 6. Plant network according to one of the preceding claims, characterized in that the coarse process condensate purification device (20) has a third heat exchanger (24), the coarse process condensate purification device (20) having a recirculation line for a partial flow of the coarsely cleaned process condensate flow, the third heat exchanger (24) in the recirculation line is designed to heat the recirculated partial flow.
7. Anlagenverbund nach einem der vorstehenden Ansprüche, dadurch gekennzeichnet, dass der Anlagenverbund ein Prozesskondensatspeicher (3) aufweist, wobei der Prozesskondensatspeicher (3) nach der Harnstoffsynthese- vorrichtung (1 ) und vor der Prozesskondensataufreinigungsvorrichtung (10) und der Grobprozesskondensataufreinigungsvorrichtung (20) angeordnet ist. 7. Plant network according to one of the preceding claims, characterized in that the plant network has a process condensate reservoir (3), the process condensate reservoir (3) being arranged after the urea synthesis device (1) and before the process condensate purification device (10) and the coarse process condensate purification device (20). is.
8. Anlagenverbund nach einem der vorstehenden Ansprüche, dadurch gekennzeichnet, dass die Grobprozesskondensataufreinigungsvorrichtung (20) und die Harnstoffsynthesevorrichtung (1 ) über eine erste Leistung zur Rückführung des aus der Grobprozesskondensataufreinigungsvorrichtung (20) austretenden Carbamatstromes verbunden sind. 8. Plant network according to one of the preceding claims, characterized in that the coarse process condensate purification device (20) and the urea synthesis device (1) are connected via a first output for the return of the coarse process condensate purification device (20) exiting carbamate stream.
9. Anlagenverbund nach Anspruch 8, dadurch gekennzeichnet, dass die Prozesskondensataufreinigungsvorrichtung (10) und die Harnstoffsynthesevorrichtung (1 ) über eine zweite Leistung zur Rückführung des aus der Prozesskondensataufreinigungsvorrichtung (10) austretenden Carbamatstromes verbunden sind, wobei die erste Leitung und die zweite Leitung miteinander verbunden sind. 9. Plant network according to claim 8, characterized in that the process condensate purification device (10) and the urea synthesis device (1) via a second output for recirculating the process condensate purification device (10) exiting Carbamate stream are connected, wherein the first line and the second line are interconnected.
PCT/EP2023/053567 2022-02-18 2023-02-14 Optimized process condensate preparation WO2023156360A1 (en)

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LU102914A LU102914B1 (en) 2022-02-18 2022-02-18 Optimized process condensate treatment
LULU102914 2022-02-18
DE102022201727.7 2022-02-18
DE102022201727.7A DE102022201727A1 (en) 2022-02-18 2022-02-18 Optimized process condensate treatment

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Citations (10)

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US4410503A (en) 1981-02-28 1983-10-18 Unie Van Kunst-Mestfabrieken Process for the removal of urea, ammonia, and carbon dioxide from dilute aqueous solutions
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WO2021137701A1 (en) * 2019-12-30 2021-07-08 Stamicarbon B.V. Urea production with multiple evaporators
WO2021137700A1 (en) * 2019-12-30 2021-07-08 Stamicarbon B.V. Ammonia removal from urea finishing

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1528051A (en) * 1974-09-30 1978-10-11 Foster Wheeler Energy Corp Pollution control process for fertilizer plant
DE3002460A1 (en) * 1979-01-30 1980-08-21 Cf Ind PROCESS AND DEVICE FOR AFTER-TREATMENT, IN PARTICULAR FOR UREA AND AMMONNITRATE PLANTS
US4410503A (en) 1981-02-28 1983-10-18 Unie Van Kunst-Mestfabrieken Process for the removal of urea, ammonia, and carbon dioxide from dilute aqueous solutions
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EP3782979A1 (en) * 2019-08-20 2021-02-24 Yara International ASA Preparation of urea solution and facility to do so
WO2021137701A1 (en) * 2019-12-30 2021-07-08 Stamicarbon B.V. Urea production with multiple evaporators
WO2021137700A1 (en) * 2019-12-30 2021-07-08 Stamicarbon B.V. Ammonia removal from urea finishing

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