System and method for reducing ammonia emissions within an industrial facility

Abstract

In a first aspect, this disclosure provides a system comprising a first device, a second device, a scrubber in fluid communication with the second device, and an injector in fluid communication with both the first and second devices. In another aspect, this disclosure provides a method for removing ammonia from a first gaseous stream generated by the first device, the first gaseous stream containing ammonia and having a pressure of at most atmospheric pressure.

Description

Technical Field

[0001] This disclosure relates to the field of chemical engineering, and in particular to reducing ammonia emissions in industrial facilities (especially fertilizer or urea production facilities). Background Technology

[0002] Industrial facilities produce large quantities of useful chemicals, but also generate significant streams of waste containing polluting compounds harmful to the environment. Ammonia (NH3) is a small nitrogen-containing molecule that can be used to manufacture a wide variety of products, including nitric acid and urea, important fertilizer products. Industrial facilities that consume ammonia to produce various products (such as fertilizer facilities) often generate gaseous waste streams containing ammonia and are typically subject to strict regulations that limit the amount of ammonia they are allowed to release into the atmosphere.

[0003] Therefore, there is a ongoing need to create new systems that can further reduce ammonia emissions in industrial facilities. Summary of the Invention

[0004] It has been found that by using an ejector and a second gaseous stream containing ammonia at a pressure higher than atmospheric pressure, a gaseous stream containing ammonia at a pressure of up to atmospheric pressure can be treated in a scrubber to reduce its ammonia concentration.

[0005] In a first aspect, this disclosure provides a system, particularly a system within a urea production facility, said system comprising:

[0006] (i) A first device, the first device being capable of discharging a first gaseous stream containing ammonia at a pressure of at most atmospheric pressure;

[0007] (ii) A second device configured to generate a second gaseous stream containing ammonia at a pressure above atmospheric pressure (e.g., at a pressure of at least 0.2 MPa), wherein the second gaseous stream is split into a first portion and a second portion downstream of the second device;

[0008] (iii) A scrubber in fluid communication with the second device, the scrubber being configured to receive at least the first portion of the second gaseous stream and remove ammonia therefrom; and

[0009] (iv) An injector comprising a first inlet for the first gaseous flow, a second inlet for a second portion of the second gaseous flow as a motive fluid, and an outlet for a third gaseous flow comprising the first gaseous flow and the second portion of the second gaseous flow;

[0010] The system is further configured to inject the third gaseous flow directly into the washer via a conduit between the ejector outlet and the washer; or to inject the third gaseous flow, which is combined with the first portion of the second gaseous flow, into the washer via a conduit between the second device and the washer.

[0011] In a particular embodiment, the second device is an absorber; and / or the first device is an absorber configured to operate at atmospheric pressure, a pressure relief valve, or a container configured to contain an aqueous solution, particularly a container for containing an aqueous solution containing ammonia and / or urea.

[0012] In a particular embodiment, the scrubber is configured to remove ammonia from the second gaseous stream by contacting the second gaseous stream with an aqueous solution containing an acid, particularly wherein the aqueous solution contains nitric acid, phosphoric acid, or sulfuric acid; and / or the scrubber is configured to release a fourth gaseous stream of depleted ammonia via a gas outlet, wherein the fourth gaseous stream is at atmospheric pressure.

[0013] In another related aspect, this disclosure provides a method for removing ammonia from a first gaseous stream generated by a first device, the first gaseous stream containing ammonia and having a pressure at most atmospheric pressure, the method comprising the steps of:

[0014] (a) The first gaseous flow is directed to an ejector (particularly the pressure of the first gaseous flow is in the range of 1 kPa to 101 kPa), the ejector being in fluid communication with a scrubber, wherein the scrubber is in fluid communication with a second device and is configured to receive at least a first portion of the second gaseous flow from the second device and remove ammonia therefrom, particularly wherein the pressure of the second gaseous flow is in the range of 105 kPa to 400 kPa.

[0015] (b) directing a second portion of the second gaseous flow from the second device to the ejector, such that the second portion of the second gaseous flow is used by the ejector as a motive fluid to generate a third gaseous flow comprising the first gaseous flow and the second portion of the second gaseous flow, the third gaseous flow having a pressure higher than atmospheric pressure (particularly wherein the pressure of the third gaseous flow is in the range of 105 kPa to 400 kPa), and directing the first portion of the second gaseous flow to the scrubber;

[0016] (c) Directing the third gaseous flow to the washer;

[0017] (d) Providing the scrubber with an acidic aqueous solution and removing ammonia from a first portion of the second gaseous stream and from the third gaseous stream; and

[0018] (e) In particular, a fourth gaseous stream of depleted ammonia is recovered from the gas outlet of the scrubber, wherein the fourth gaseous stream is at atmospheric pressure.

[0019] In a particular embodiment, the ammonia concentrations of the first gaseous stream, the second gaseous stream, and the third gaseous stream are in the range of 1 to 10,000 ppm.

[0020] In another related aspect, this disclosure provides a method for converting an existing system into a system according to this disclosure, wherein the existing system (particularly an existing system within a urea production facility) comprises:

[0021] (i) A first device, the first device being capable of discharging a first gaseous stream containing ammonia at a pressure of at most atmospheric pressure.

[0022] (ii) A second device, configured to generate a second gaseous stream containing ammonia at a pressure higher than atmospheric pressure, and

[0023] (iii) A scrubber in fluid communication with the second device, the scrubber being configured to receive the second gaseous stream and remove ammonia from the second gaseous stream;

[0024] The modification includes the following steps:

[0025] (a) Install the injector and split the second gaseous flow into a first portion and a second portion, wherein the first portion of the second gaseous flow is directed to the scrubber;

[0026] (b) The injector is fluidly connected to the first device to direct the first gaseous flow to the injector, and the injector is fluidly connected to the second device to direct the second portion of the second gaseous flow as a motive fluid to the injector;

[0027] (c) A third gaseous flow generated by the ejector and comprising the second portion of the first gaseous flow and the second gaseous flow is directed from the outlet of the ejector to the scrubber, or the third gaseous flow is combined with the first portion of the second gaseous flow and the combined gaseous flow is directed to the scrubber.

[0028] In another related aspect, this disclosure provides the use of an injector for injecting a first gaseous stream containing ammonia at a pressure of at most atmospheric pressure into a scrubber located within a urea production facility, the injection being used as a motive fluid by generating a third gaseous stream having a pressure above atmospheric pressure and containing a portion of the first gaseous stream and a second gaseous stream containing ammonia at a pressure above atmospheric pressure, and directing the third gaseous stream to the scrubber. Attached Figure Description

[0029] The following description of a specific embodiment of the system according to this disclosure is given by way of example only and is not intended to limit the scope of this explanation, its application, or its use. In the drawings, the same reference numerals refer to the same or similar parts and features.

[0030] Figure 1 An embodiment of a system according to this disclosure is shown. Detailed Implementation

[0031] Unless otherwise defined, all terms (including technical and scientific terms) used in disclosing this invention have the meanings commonly understood by one of ordinary skill in the art to which this invention pertains. Further guidance includes terminology definitions to better understand the teachings of this invention.

[0032] All references cited in this description are hereby considered to be incorporated herein by reference in their entirety.

[0033] As used herein, the following terms have the following meanings:

[0034] As used herein, unless the context clearly specifies otherwise, “a,” “an,” and “the” refer to the singular and plural forms, respectively. For example, “an apparatus” means one or more apparatuses.

[0035] As used herein, the terms “comprise,” “comprising,” “comprises,” and “comprised of” are synonymous with “include,” “including,” “includes,” or “contain,” “containing,” and are inclusive or open-ended terms that indicate the presence of a subsequent object (e.g., a component) but do not exclude or prevent the presence of any additional unlisted components, features, elements, components, or steps known in the art or disclosed herein.

[0036] The range of values ​​listed by endpoints includes all numbers and fractions that fall within that range, as well as the listed endpoints.

[0037] In a first aspect, this disclosure provides a system, particularly a system included within a urea production facility, comprising: a first device capable of discharging a first gaseous stream containing ammonia at a pressure of at most atmospheric pressure; a second device configured to generate a second gaseous stream containing ammonia at a pressure above atmospheric pressure; and a scrubber in fluid communication with the second device, the scrubber configured to receive the second gaseous stream and remove ammonia from the second gaseous stream, wherein the system includes an injector in fluid communication with the first device and the second device, the injector being configured to inject the first gaseous stream into the scrubber using a portion of the second gaseous stream as a driving fluid.

[0038] In other words, at the outlet of the ejector, a third gaseous flow is generated, which is a combination of the portions of the first and second gaseous flows that are used as motive fluid in the ejector. It should be understood that the system of this disclosure is configured such that this third gaseous flow is provided directly to the scrubber (e.g., via a conduit between the scrubber outlet and scrubber inlet), or is provided to the scrubber in combination with another gaseous flow directed to the scrubber (particularly with a portion of the second gaseous flow that is not used as motive fluid in the ejector) (e.g., via a conduit between the second device and the scrubber inlet). It should also be understood that, except for the optional step of combining the third gaseous flow with another gaseous flow provided to the scrubber (e.g., a portion of the second gaseous flow that is not used as motive fluid in the ejector), the third gaseous flow undergoes no treatment or processing steps (particularly changes in composition or pressure) before being introduced into the scrubber. Specifically, the system of the apparatus is configured to provide the third gaseous flow to the scrubber without providing or directing it to the first or second device before introducing it into the scrubber.

[0039] Therefore, this disclosure specifically provides a system, particularly a system included in a urea production facility, the system comprising:

[0040] (i) A first device, the first device being capable of discharging a first gaseous stream containing ammonia at a pressure of up to atmospheric pressure;

[0041] (ii) A second device configured to generate a second gaseous flow containing ammonia at a pressure higher than atmospheric pressure, wherein downstream of the second device, the second gaseous flow is split into a first portion and a second portion;

[0042] (iii) A scrubber in fluid communication with the second device, the scrubber being configured to receive the second gaseous stream (particularly at least the first portion of the second gaseous stream) and remove ammonia therefrom; and

[0043] (iv) The injector includes a first inlet for the first gaseous flow, a second inlet for the second portion of the second gaseous flow as a motive fluid, and an outlet for a third gaseous flow comprising the first gaseous flow and the second portion of the second gaseous flow;

[0044] The system (particularly the injector) is also configured to inject the third gaseous flow directly into the washer via a conduit between the injector outlet and the washer inlet, or to combine the third gaseous flow with the first portion of the second gaseous flow and inject this combination of the third gaseous flow and the first portion of the second gaseous flow into the washer (particularly via a conduit between the second device and the washer).

[0045] More specifically, this disclosure provides a system, particularly a system included within a urea production facility, said system comprising:

[0046] (i) A first device, the first device being capable of discharging a first gaseous stream containing ammonia at a pressure of at most atmospheric pressure;

[0047] (ii) A second device configured to generate a second gaseous flow containing ammonia at a pressure above atmospheric pressure, and a branch line connected to the outlet of the second device for splitting the second gaseous flow generated by the second device into a first portion and a second portion, wherein the branch line includes a first section for conveying the first portion of the second gaseous flow to a washer and a second section for conveying the second portion of the second gaseous flow.

[0048] (iv) A scrubber in fluid communication with the second device (particularly via a first section of a branch line), the scrubber being configured to receive at least the first portion of the second gaseous flow and to remove ammonia therefrom; and

[0049] (v) An injector comprising a first inlet for a first gaseous flow, a second inlet for a second portion of a second gaseous flow as a motive fluid, and an outlet for a third gaseous flow comprising the first gaseous flow and the second portion of the second gaseous flow;

[0050] The system (particularly the ejector) is configured to inject a third gaseous flow into the washer, either via a conduit between the ejector outlet and the washer (i.e., a conduit connecting the ejector outlet and the washer inlet), or via a conduit between the ejector outlet and a second section of a branch conduit between the second device and the washer. It should be understood that, in the latter embodiment, the system is specifically configured to combine the third gaseous flow with a second portion of the second gaseous flow (particularly within the second section of the branch conduit), and to provide the combined gaseous flow to the washer via the second section of the branch conduit. In other words, in a particular embodiment, the outlet of the second device is connected via a branch conduit to the motive fluid inlet of the ejector (particularly via a first section of the branch conduit) and to the inlet of the washer (particularly via a second section of the branch conduit); and the outlet of the ejector is directly connected to a conduit to the washer inlet or to the second section of the branch conduit.

[0051] Industrial facilities that consume ammonia may include one or more scrubbers. A scrubber is a device configured to receive a gaseous stream and remove contaminants, such as ammonia, from that stream. Contaminants can be removed using a variety of different technologies. A common technique for removing ammonia from a gaseous stream is to contact the stream with an aqueous solution containing an acid. Upon contact with the aqueous solution, the ammonia dissolves in the water and reacts with the acid to form ammonium ions, which are soluble in water. Therefore, the scrubber produces two streams: a gaseous stream depleted of ammonia and an aqueous solution containing ammonium ions. A scrubber includes at least one gas inlet, one gas outlet, one liquid inlet, and one liquid outlet. In some embodiments, the scrubber includes at least two gas inlets. In some embodiments, the scrubber includes at least three gas inlets.

[0052] Scrubbers can be configured to operate at different pressures, but most industrial facilities include at least scrubbers configured to operate at atmospheric pressure or slightly above atmospheric pressure, and the depleted ammonia gaseous stream generated by the scrubber is released into the atmosphere.

[0053] Such a scrubber requires the gaseous flow to be purified to have a pressure higher than atmospheric pressure, for example, a pressure of at least 105 kPa, so that the gaseous flow can flow from the gas inlet to the gas outlet of the stripper.

[0054] A scrubber may not be able to completely remove all the ammonia contained in a gaseous stream, but it can reduce the ammonia content in the gaseous stream to such a low level, for example, below 0.1 ppm, that it is safe and legal to release the gaseous stream into the atmosphere.

[0055] Industrial facilities (such as fertilizer facilities or urea production facilities) typically include several devices capable of discharging gaseous streams containing ammonia (which need to be purified before being released into the atmosphere). These devices can be configured to operate at different pressures (depending on their exact function).

[0056] In some embodiments, the apparatus capable of discharging a first gaseous stream containing ammonia is selected from the group consisting of: absorption towers, pressure relief valves, or containers configured to contain aqueous solutions, particularly containers configured to contain aqueous solutions containing ammonia and / or urea. Industrial facilities (such as fertilizer facilities or urea production facilities) may include containers or tanks configured to hold or contain aqueous solutions, which may contain free ammonia, ammonium ions, and / or urea dissolved in water. These solutions are capable of discharging a gaseous stream containing ammonia. The aqueous solution may be a process condensate, i.e., an aqueous solution obtained by condensing a gaseous stream containing water vapor.

[0057] In some implementations, the container configured to contain the aqueous solution can be any container configured to operate at atmospheric pressure, i.e., both the solution contained in the container and the gas in the top space of the container are designed to be at atmospheric pressure.

[0058] An absorber is a device comprising at least one gas inlet and at least one gas outlet. The absorber includes a material suitable for absorbing components contained in a gaseous stream. The absorber can be used to remove ammonia from a gaseous stream, but the gas released from the gas outlet may still contain an amount of ammonia that makes it unsuitable for release into the atmosphere. In some embodiments, the material suitable for absorbing components such as ammonia is an aqueous solution. In some embodiments, the absorber may include a liquid inlet for an absorbent liquid, a liquid outlet for an absorbent liquid containing dissolved components from the gaseous stream, a gas inlet, and a gas outlet.

[0059] In some implementations, the absorber includes two or more liquid inlets. Some absorbers may include different absorption stages, each requiring a liquid inlet to feed the absorbent into each stage. Such absorbers may include one or more liquid outlets. Solutions containing the absorbed components can converge within the absorber, requiring only one liquid outlet, thereby simplifying the connection of the absorber to the rest of the facility.

[0060] A pressure relief valve is a type of pressure relief component configured to be in fluid communication with another device or pipeline: when the pressure inside the device or pipeline reaches a certain critical value, the pressure relief valve opens and allows fluid present in the device or pipeline to escape through the valve, thereby reducing the pressure inside the device or pipeline. The pressure relief valve may not be completely hermetically sealed to the device or pipeline, so it may continuously release a very small amount of gaseous flow during operation. Such a discharge can be referred to as a "fusible discharge" of the pressure relief valve. Therefore, it may be advantageous to connect the pressure relief valve to a scrubber via an ejector to remove ammonia from the gaseous flow discharged from the valve.

[0061] A second device included in the system is configured to generate a second gaseous stream containing ammonia at a pressure above atmospheric pressure. Industrial facilities (such as fertilizer facilities or urea production facilities) typically include devices operating at different pressures and typically include at least one device operating at a pressure above atmospheric pressure. For example, the second device may be an absorber configured to receive the gaseous stream at a pressure above atmospheric pressure to reduce the content of one or more components in the gaseous stream and to release the depleted gaseous stream at a pressure above atmospheric pressure.

[0062] Such a device can be connected to a washer that operates at atmospheric pressure without the need for any additional devices (such as a fan or pump) because the pressure difference between the outlet of the second device and the inlet of the washer is positive.

[0063] Different systems and methods can be used to remove ammonia from the first gaseous stream discharged from the first device. However, the system according to this disclosure has several important advantages: it requires minimal disturbance to the system, it has extremely low cost, and it is highly efficient in removing ammonia from the first gaseous stream.

[0064] This system includes an ejector in fluid communication with a first device and a second device, the ejector being configured to generate a third gaseous flow and inject this third gaseous flow into a scrubber. The ejector is a device comprising two fluid inlets and one fluid outlet. It can be configured to receive one gaseous flow and one liquid flow, two liquid flows, or two gaseous flows. The two flows have different pressures, and utilizing the Venturi effect, the two flows are merged to form a new flow with a pressure between the pressures of the two flows received by the ejector. The fluid flow with the highest pressure is generally referred to as the motive fluid, and the fluid with the lowest pressure is generally referred to as the suction fluid. In this disclosure, the motive fluid is a first portion of the second gaseous flow generated by the second device, and the suction fluid is the first gaseous flow.

[0065] The second gaseous stream is configured to be directed to the scrubber, and in this system, the ejector receives the portion of the second gaseous stream intended to be used as the motive fluid, while the remainder of the second gaseous stream is still configured to be directly injected into the scrubber, specifically operating at atmospheric pressure, i.e., without any additional devices such as fans or pumps, because the pressure difference between the outlet of the second device and the inlet of the scrubber is positive. This allows the ejector to convert a first gaseous stream containing ammonia, operating at at most atmospheric pressure, into a third gaseous stream containing ammonia, operating at a pressure higher than atmospheric pressure. Because the pressure difference between the ejector outlet and the inlet of the scrubber (operating at atmospheric pressure) is positive, the third gaseous stream is configured to be directly injected (separately or combined with the remainder of the second gaseous stream) into the scrubber, i.e., without any additional devices such as fans, pumps, or compressors.

[0066] The ammonia content of the third gaseous stream can be higher or lower than that of the first gaseous stream, depending on the ammonia content of the second gaseous stream.

[0067] Adding an injector to the system is minimal, because all of the second gaseous stream still enters the scrubber, allowing the scrubber to capture some or all of the ammonia contained in the second gaseous stream generated by the second device. Furthermore, the ammonia contained in the first gaseous stream is also partially or completely captured by the scrubber.

[0068] In some implementations, the first device is capable of discharging a first gaseous stream containing ammonia at a pressure ranging from 1 kPa to 101 kPa.

[0069] In some embodiments, the second device is configured to generate a second gaseous flow containing ammonia at a pressure of at least 0.2 MPa. In some embodiments, the second device is configured to generate a second gaseous flow containing ammonia at a pressure in the range of 0.2 MPa to 1.0 MPa. Urea production facilities typically include a high-pressure section (where the pressure of the gaseous flow is above 1.0 MPa) and a low-pressure section (where the pressure of the gaseous flow is from 0.105 MPa to 0.4 MPa). Additionally, some urea facilities include a medium-pressure section (where the pressure of the gaseous flow is from 0.4 MPa to 1.0 MPa).

[0070] In some implementations, the second device is located in the low-pressure section of the urea production facility.

[0071] In some embodiments, the system according to this disclosure is included within a urea production facility.

[0072] In some implementations, the second device is an absorber.

[0073] In some implementations, the first device is a device located within a urea production facility.

[0074] In some embodiments, the first device is a container configured to contain an aqueous solution of ammonia, particularly a container configured to contain process condensate. Industrial facilities typically generate streams of water-containing waste at atmospheric pressure. For example, it may include one or more condensers configured to condense a gaseous stream containing water vapor. If the gaseous stream contains water vapor and ammonia, the solution obtained by condensing the gaseous stream is an aqueous solution containing ammonia. Such an aqueous solution can be stored in a container at atmospheric pressure, and the gaseous stream containing ammonia may be discharged due to the low boiling point (-33 °C) and low vapor pressure of ammonia.

[0075] In some implementations, the first device is an absorber configured to operate at or below atmospheric pressure.

[0076] In some implementations, the scrubber is configured to remove ammonia from the gaseous stream by contacting it with an aqueous solution containing an acid, particularly nitric acid, phosphoric acid, or sulfuric acid. The scrubber can operate in different ways to remove contaminants (especially ammonia) from the gaseous stream, but one of these methods involves contacting the gaseous stream with an acidic aqueous solution. Ammonia has limited solubility in water, but if it reacts with an acid, it forms ammonium ions, which are generally highly soluble in water. Acids such as nitric acid, phosphoric acid, and sulfuric acid are frequently used in industrial facilities (particularly fertilizer production facilities), and these acids react very rapidly with ammonia to form ion pairs with high water solubility, making them good acids to add to the aqueous solution of the scrubber.

[0077] In some embodiments, the scrubber is configured to release a gaseous stream of depleted ammonia via a gas inlet at atmospheric pressure or slightly above atmospheric pressure, such as 102 kPa, 103 kPa, or 104 kPa.

[0078] In another aspect, this disclosure provides a method for removing ammonia from a first gaseous stream generated by a first device, the first gaseous stream containing ammonia and having a pressure of at most atmospheric pressure, the method comprising the following steps:

[0079] a. Directing the first gaseous flow to an injector, the injector being in fluid communication with a scrubber, wherein the scrubber is in fluid communication with a second device and is configured to receive a second gaseous flow from the second device and remove ammonia from the second gaseous flow, such as being configured to receive at least a first portion of the second gaseous flow from the second device and remove ammonia therefrom;

[0080] b. A portion of the second gaseous flow from the second device (particularly a second portion of the second gaseous flow) is directed to the ejector, such that the portion of the second gaseous flow is used as a motive fluid by the ejector, thereby generating a third gaseous flow comprising the first gaseous flow and the portion of the second gaseous flow, the third gaseous flow having a pressure higher than atmospheric pressure, wherein the remaining portion of the second gaseous flow not directed to the ejector (particularly the first portion of the second gaseous flow) is directed to the scrubber;

[0081] c. Direct the third gaseous stream to the washer;

[0082] d. To provide an acidic aqueous solution to the scrubber, and in particular to remove ammonia from the second and third gaseous streams; and

[0083] e. In particular, a fourth gaseous stream of depleted ammonia is recovered from the gas outlet of the scrubber, especially wherein the fourth gaseous stream is at atmospheric pressure.

[0084] In this method, two gaseous streams are provided to the ejector: a first gaseous stream containing ammonia at a pressure of at most atmospheric pressure, and a second gaseous stream containing ammonia (particularly a portion of the second gaseous stream) at a pressure higher than atmospheric pressure. The first and second gaseous streams (particularly the aforementioned portions of the first and second gaseous streams) merge inside the ejector to generate a third gaseous stream exiting the ejector.

[0085] The third gaseous stream contains ammonia and has a pressure higher than atmospheric pressure, which is at most the pressure of the second gaseous stream. The third gaseous stream exiting the ejector can be directed directly to the scrubber. Alternatively, the third gaseous stream can be mixed with another gaseous stream directed to the scrubber. In some embodiments, the third gaseous stream is mixed with the remainder of the second gaseous stream that was not directed to the ejector, and the gaseous stream containing both the third and second gaseous streams is directed to the scrubber.

[0086] The scrubber continuously receives an acidic aqueous solution, which interacts with the gaseous stream entering the scrubber. Following this interaction, ammonia contained in the gaseous stream dissolves into the aqueous solution and reacts with the acid present to form ammonium ions. The reaction of free ammonia to ammonium drives the dissolution of gaseous ammonia in the aqueous solution.

[0087] In some embodiments, the acidic aqueous solution contains one or more compounds selected from the group consisting of nitric acid, phosphoric acid, and sulfuric acid. These acids are commonly used in fertilizer production and are readily available on-site.

[0088] The scrubber may include means for generating a mist using an acidic aqueous solution. Generating a mist increases the surface area for interaction between the gaseous stream and the acidic aqueous solution, and can improve the removal of ammonia from the gaseous stream.

[0089] The scrubber may include a pad or a filter. Using a pad or filter in the scrubber improves the interaction between the gaseous stream and the acidic aqueous solution, and improves the removal of ammonia from the gaseous stream. The acidic aqueous solution can be sprayed onto the pad or filter.

[0090] In some implementations, the pressure of the first gaseous flow is in the range of 1 kPa to 101 kPa.

[0091] In some implementations, the pressure of the second gaseous flow is in the range of 105 kPa to 400 kPa.

[0092] In some implementations, the pressure of the third gaseous flow is in the range of 105 kPa to 400 kPa.

[0093] In some embodiments, the ammonia concentration in the first gaseous stream is in the range of 1 to 10,000 ppm, 10 to 10,000 ppm, 10 to 1,000 ppm, 100 to 10,000 ppm, or 100 to 1,000 ppm. The ammonia concentration in the first gaseous stream depends on the source of the first gaseous stream.

[0094] In some implementations, the ammonia concentration of the second gaseous stream is in the range of 1 to 10,000 ppm.

[0095] In some embodiments, the ammonia concentration in the third gaseous stream at the injector outlet is in the range of 1 to 10,000 ppm, 10 to 10,000 ppm, 10 to 1,000 ppm, 100 to 10,000 ppm, or 100 to 1,000 ppm. The ammonia concentration in the third gaseous stream depends on the ammonia concentration in the first gaseous stream and the ammonia concentration in the second gaseous stream.

[0096] The first gaseous stream, the second gaseous stream, and the third gaseous stream can have the same ammonia concentration or different concentrations.

[0097] In some embodiments, the ammonia concentration of the fourth gaseous stream recovered from the scrubber is at most 100 ppm, at most 50 ppm, at most 10 ppm, or at most 1 ppm. In some embodiments, the ammonia concentration of the fourth gaseous stream recovered from the scrubber is in the range of 0 to 100 ppm, 0 to 50 ppm, 0 to 10 ppm, or 0 to 5.0 ppm. The scrubber can achieve extremely high ammonia removal rates from the gaseous stream and produce a gaseous stream that can be safely and legally released into the atmosphere.

[0098] In another aspect, this disclosure provides a method for retrofitting a facility, the facility comprising: a first device capable of discharging a first gaseous stream containing ammonia at a pressure of up to atmospheric pressure; a second device configured to generate a second gaseous stream containing ammonia at a pressure above atmospheric pressure; and a scrubber in fluid communication with the second device, the scrubber configured to receive the second gaseous stream and remove ammonia from the second gaseous stream, the method comprising the step of: fluidly communicating an injector with the first and second devices, the injector being configured to use a portion of the second gaseous stream as a driving fluid to inject the first gaseous stream into the scrubber.

[0099] In some implementation schemes, the modification is carried out within the urea production facility.

[0100] More specifically, this disclosure provides a method for transforming an existing system into a system according to this disclosure, wherein the existing system includes:

[0101] (i) A first device, the first device being capable of discharging a first gaseous stream containing ammonia at a pressure of at most atmospheric pressure;

[0102] (ii) a second device, the second device being configured to generate a second gaseous stream containing ammonia at a pressure above atmospheric pressure; and

[0103] (iii) A scrubber in fluid communication with the second device, the scrubber being configured to receive the second gaseous stream and remove ammonia from the second gaseous stream;

[0104] The modification includes the following steps:

[0105] (a) Install an injector and split the second gaseous flow into a first portion and a second portion, wherein the first portion of the second gaseous flow is directed to the scrubber;

[0106] (b) The injector is fluidly connected to the first device to direct the first gaseous flow to the injector, and the injector is fluidly connected to the second device to direct the second portion of the second gaseous flow as a motive fluid to the injector;

[0107] (c) A third gaseous flow generated by the ejector and comprising the second portion of the first gaseous flow and the second gaseous flow is directed from the outlet of the ejector to the scrubber, or the third gaseous flow is combined with the first portion of the second gaseous flow and the combined gaseous flow is directed to the scrubber.

[0108] In another aspect, this disclosure provides the use of an injector for injecting a first gaseous stream containing ammonia at a pressure of up to atmospheric pressure into a scrubber, said injection using a portion of a second gaseous stream containing ammonia at a pressure above atmospheric pressure as a motive fluid.

[0109] In particular, this disclosure provides the use of an injector for injecting a first gaseous stream containing ammonia at a pressure of at most atmospheric pressure into a scrubber located within a urea production facility, the injection being used as a motive fluid by generating a third gaseous stream having a pressure above atmospheric pressure and containing a portion of the first gaseous stream and a second gaseous stream containing ammonia at a pressure above atmospheric pressure, and directing the third gaseous stream to the scrubber.

[0110] Figure 1 An embodiment of a system according to this disclosure is shown. The system includes a first device 1 (e.g., an absorber) that discharges a first gaseous stream containing ammonia at atmospheric pressure during operation. The absorber may be in fluid communication with a container configured to contain an aqueous solution containing ammonia (e.g., process condensate). The system also includes a second device 2, which may also be an absorber and is configured to generate a second gaseous stream containing ammonia at a pressure above atmospheric pressure (e.g., between 300 and 400 kPa). The second device 2 is in fluid communication via a conduit 6 with an acid scrubber 3 configured to remove ammonia from the gaseous stream using an acidic aqueous solution. The system includes an ejector 4, which is in fluid communication with the first device 1 via a conduit 5 and with the second device 2 via a conduit 7. The ejector 4 is configured to receive a portion of the second gaseous stream generated by the second device 2 and utilize that stream as a driving fluid to increase the pressure of the first gaseous stream discharged from the first device 1. The outlet of the ejector 4 is in fluid communication with the conduit 6 via a conduit 8, such that a third gaseous stream generated by the ejector 4 is directed to the scrubber 3. The scrubber 3 includes a gas inlet (for receiving a mixture of a second gaseous stream and a third gaseous stream), a liquid inlet 10 (for receiving an acidic aqueous solution), a liquid outlet 9 (for removing an aqueous solution containing ammonium ions from the scrubber), and a gas outlet 11 (for removing a fourth gaseous stream that has been depleted of ammonia from the scrubber 3).

Claims

1. A system comprising: (i) A first device, the first device being capable of discharging a first gaseous stream containing ammonia at a pressure of at most atmospheric pressure; (ii) A second device configured to generate a second gaseous stream containing ammonia at a pressure above atmospheric pressure, wherein the second gaseous stream is split into a first portion and a second portion downstream of the second device; (iii) A scrubber in fluid communication with the second device, the scrubber being configured to receive at least the first portion of the second gaseous flow and remove ammonia therefrom; The system is characterized in that it further includes (iv) an injector, the injector comprising a first inlet for the first gaseous flow, a second inlet for the second portion of the second gaseous flow as a motive fluid, and an outlet for a third gaseous flow comprising the first gaseous flow and the second portion of the second gaseous flow; The system is further configured to inject the third gaseous flow directly into the washer via a conduit between the ejector outlet and the washer; or to inject the third gaseous flow, which is combined with the first portion of the second gaseous flow, into the washer via a conduit between the second device and the washer.

2. The system of claim 1, wherein the system is contained within a urea production facility.

3. The system according to claim 1 or 2, wherein the second device is configured to generate a second gaseous flow containing ammonia at a pressure of at least 0.2 MPa.

4. The system according to any one of claims 1 to 3, wherein the second device is an absorber.

5. The system according to any one of claims 1 to 4, wherein the first device is an absorber configured to operate at atmospheric pressure, a pressure relief valve, or a container configured to contain an aqueous solution, particularly a container configured to contain an aqueous solution comprising ammonia and / or urea.

6. The system according to any one of claims 1 to 5, wherein the scrubber is configured to remove ammonia from the second gaseous stream by contacting the second gaseous stream with an aqueous solution containing an acid, particularly wherein the aqueous solution contains nitric acid, phosphoric acid, or sulfuric acid.

7. The system according to any one of claims 1 to 6, wherein the scrubber is configured to release a fourth gaseous stream of depleted ammonia via a gas outlet, wherein the fourth gaseous stream is at atmospheric pressure.

8. A method for removing ammonia from a first gaseous stream generated by a first device, the first gaseous stream containing ammonia and having a pressure of at most atmospheric pressure, the method comprising the steps of: a. Directing the first gaseous flow to an injector, the injector being in fluid communication with a scrubber, wherein the scrubber is in fluid communication with a second device and is configured to receive at least a first portion of the second gaseous flow from the second device and to remove ammonia therefrom; b. Directing a second portion of the second gaseous flow from the second device to the ejector, such that the second portion of the second gaseous flow is used as a motive fluid by the ejector, thereby generating a third gaseous flow comprising the first gaseous flow and the second portion of the second gaseous flow, the third gaseous flow having a pressure higher than atmospheric pressure, and directing the first portion of the second gaseous flow to the washer; c. Direct the third gaseous stream to the washer; d. Provide the scrubber with an acidic aqueous solution and remove ammonia from a first portion of the second gaseous stream and from the third gaseous stream.

9. The method according to claim 8, further comprising the following step: e. Recover a fourth gaseous stream of depleted ammonia from the gas outlet of the scrubber, wherein the fourth gaseous stream is at atmospheric pressure.

10. The method according to claim 8 or 9, wherein the pressure of the first gaseous flow is in the range of 1 kPa to 101 kPa.

11. The method according to any one of claims 8 to 10, wherein the pressure of the second gaseous flow is in the range of 105 kPa to 400 kPa.

12. The method according to any one of claims 8 to 11, wherein the pressure of the third gaseous flow is in the range of 105 kPa to 400 kPa.

13. The method according to any one of claims 8 to 12, wherein the ammonia concentration of the first gaseous stream, the second gaseous stream, and the third gaseous stream is in the range of 1 to 10,000 ppm.

14. A method for converting an existing system into a system according to any one of claims 1 to 7, wherein the existing system comprises: (i) A first device, the first device being capable of discharging a first gaseous stream containing ammonia at a pressure of at most atmospheric pressure; (ii) A second device, the second device being configured to generate a second gaseous flow containing ammonia at a pressure higher than atmospheric pressure; and (iii) A scrubber in fluid communication with the second device, the scrubber being configured to receive the second gaseous stream and remove ammonia from the second gaseous stream; The modification includes the following steps: (a) Install an injector and split the second gaseous flow into a first portion and a second portion, wherein the first portion of the second gaseous flow is directed to the scrubber; (b) The injector is fluidly connected to the first device to direct the first gaseous flow to the injector, and the injector is fluidly connected to the second device to direct the second portion of the second gaseous flow as a motive fluid to the injector; (c) A third gaseous flow generated by the ejector and comprising the second portion of the first gaseous flow and the second gaseous flow is directed from the outlet of the ejector to the scrubber, or the third gaseous flow is combined with the first portion of the second gaseous flow and the combined gaseous flow is directed to the scrubber.

15. The method of claim 14, wherein the facility is a urea production facility.

16. An injector for injecting a first gaseous stream containing ammonia at a pressure of at most atmospheric pressure into a scrubber located within a urea production facility, the injection being used as a motive fluid by generating a third gaseous stream having a pressure above atmospheric pressure and containing a portion of the first gaseous stream and a second gaseous stream containing ammonia at a pressure above atmospheric pressure, and directing the third gaseous stream to the scrubber.

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