System and method for preventing leaks from industrial equipment operating in corrosive environments

Abstract

This invention relates to the field of industrial treatment of high-temperature corrosive liquids originating from gas-liquid contactors in the chemical industry. The invention provides a treatment unit for preventing leakage of such liquids from equipment downstream of a gas-liquid contactor, and related methods for preventing leakage.

Description

[Technical Field]

[0001] This invention relates to the field of industrial processing of high-temperature corrosive liquids originating from gas-liquid contactors such as drip-membrane towers. In particular, this invention relates to a system and method for reducing the risk of leakage of high-temperature liquids and / or corrosive liquids downstream of a gas-liquid contactor. [Background technology]

[0002] In the chemical industry, many processes utilize aggressive, acidic, caustic, or other corrosive agents as catalysts, solutions, or working fluids to drive chemical reactions. Since chemical reactions generally proceed better or have higher conversion rates at higher temperatures, reagents coming from gas-liquid contactors, such as drip-filled membrane towers, are often at high temperatures. If these reagents are aggressive and / or corrosive, they can damage downstream processing units by attacking the components that make up those processing units.

[0003] In conventional technology, heat exchangers are often used in the chemical industry for the purpose of transferring heat between different media (e.g., corrosive liquids and air, or coolants). With regard to heat exchangers, the thermal conductivity of the materials from which they are composed is a crucial factor. Many materials, such as graphite, SiC, and glass, are corrosion-resistant and have good thermal conductivity (except glass), but they have the disadvantage of being inherently brittle; that is, they are not suitable for withstanding high pressure, and a greater pressure drop increases the rate and therefore heat transfer, resulting in mostly low allowable forces around the gaskets and / or being unsuitable for withstanding rapid pressure changes, such as those caused by starting and stopping. When exposed to these conditions, these materials crack, which contributes to the leakage of the high-temperature corrosive liquids for which they are designed to exchange heat. Leaks within these devices, which pose a high safety risk to operators, must be avoided. [Overview of the project] [Problems that the invention aims to solve]

[0004] Therefore, there is an industrial need to prevent leakage in systems with one or more heat exchangers, particularly those with gas-liquid contactors that operate at lower pressures and allow for smooth and gradual changes in operating conditions, in high-temperature and / or corrosive environments. The present invention provides a solution to the aforementioned problems. [Means for solving the problem]

[0005] According to a first aspect, the present invention relates to a processing unit for processing corrosive media such as corrosive liquid streams, basic liquid streams, or acidic liquid streams, which may be at high temperatures, wherein the processing unit It is adapted to bring the liquid from input stream A into contact with a gas such as air or water vapor, and to discharge the liquid stream B, with a height H r A gas-liquid contactor such as a flow-through membrane tower is arranged, A gas trap is positioned to receive liquid stream B and discharge liquid stream C, and is provided with a headspace for capturing gas volume to allow for bubble removal and attenuation of pressure surges in stream B. It is arranged to receive liquid stream C and discharge liquid stream D, and is equipped with a heat exchange means, at a height H c A heat exchanger is positioned, A first vacuum line L1 is fitted to supply negative gauge pressure to the headspace, thereby causing the liquid stream B to be drawn into the gas trap, It is equipped with, The pressure difference is supplied as driving force through the heat exchanger. r >H c That is the case.

[0006] This aspect of the invention offers several advantages. In particular, a processing unit configured according to this aspect minimizes the risk of leakage of the processed liquid from the heat exchanger, thereby enabling the use of materials for heat exchange means that would otherwise not be able to withstand prior art pressure processing units and / or pressure vibration processing units. According to this aspect of the invention, the pressure upstream of the heat exchanger can be easily maintained within a preferred pressure range. Due to a specific height difference between the gas-liquid contactor and the heat exchanger, it is also possible to keep the pressure within the preferred pressure range without the need to use a pump.

[0007] According to an embodiment of the invention, the processing unit is arranged to receive a liquid stream D from a heat exchanger, and has a height H of the heat exchanger to enable the static pressure in the liquid stream D in order to avoid its liquid-gas transition c higher than height H s and further comprises a gas-liquid separator arranged at that height.

[0008] According to an embodiment of the invention, the processing unit is connected to a gas-liquid contactor and further comprises a second vacuum line L2 adapted to supply a negative gauge pressure to the gas-liquid contactor, thereby causing suction of the input stream A into the gas-liquid contactor.

[0009] According to an embodiment of the invention, the first vacuum line L1 and / or the second vacuum line L2 is connected to the gas-liquid separator.

[0010] According to an embodiment of the invention, the processing unit comprises one or more pipes that are at least partially traced.

[0011] According to an embodiment of the invention, the heat exchange means of the heat exchanger comprises a material selected from graphite (C), silicon carbide (SiC), and silicon dioxide (SiO2).

[0012] According to an embodiment of the invention, the heat exchange means comprises graphite.

[0013] According to one embodiment of the present invention, the heat exchange means is selected from a tube or a tube bundle, and one or more plates.

[0014] According to one embodiment of the present invention, the gas trap is arranged at a height H L and H r > H c > H L is.

[0015] According to one embodiment of the present invention, the gas-liquid contactor is a falling film column.

[0016] According to one embodiment of the present invention, the liquid stream B and / or the liquid stream C has a pH lower than 2 or higher than 12.

[0017] According to one embodiment of the present invention, the liquid stream B and / or the liquid stream C has a temperature of 100 ° C to 300 ° C, preferably 120 ° C to 250 ° C.

[0018] According to one embodiment of the present invention, the gas-liquid contactor is a reactor configured to receive a reaction reagent that is preferably an inorganic oxo acid and / or a salt thereof, more preferably polyphosphoric acid (PPA), and to contact the reaction reagent with water.

[0019] According to one embodiment of the present invention, the treatment unit a first pumping means adapted to receive the liquid stream C and pump the liquid stream C in the direction of the heat exchanger (3); pressure measuring means provided for measuring the pressure of the liquid stream C pumped downstream of the control valve in the direction of the heat exchanger; a pressure control valve provided downstream of the first pumping means and the pressure measuring means and provided for adjusting the flow of the liquid stream C to the heat exchanger; A pressure control means adapted to maintain the pressure of liquid stream C within a predetermined pressure range by communicating with a first pumping means, a pressure measuring means, and a pressure control valve, and by activating the pressure control valve and / or the first pumping means based on the pressure measuring means, It also has the following features.

[0020] According to one embodiment of the present invention, the first pumping means comprises a motor connected to a variable frequency drive (VFD) adapted to be actuated by a pressure control means. The advantage of this embodiment is that the flow in the heat exchanger can be finely controlled and pressure spikes are reduced.

[0021] According to one embodiment of the present invention, the heat exchanger is part of an economizer adapted to bring a liquid stream E to be supplied to a gas-liquid contactor into thermal contact with a liquid stream C.

[0022] In a further embodiment, the present invention relates to the use of a gas trap positioned upstream of a heat exchanger having heat exchange means, wherein the gas trap is used to protect the heat exchange means from pressure changes.

[0023] In a further embodiment, the present invention provides a height H greater than the height of the heat exchanger, which is positioned downstream of the heat exchanger and generates static pressure at the heat exchanger's discharge. s Regarding the use of gas-liquid separators installed.

[0024] In a further embodiment, the present invention relates to a method for operating a processing unit described in any one embodiment of the processing unit of the present invention for processing a corrosive liquid, wherein the method is a) Supplying negative gauge pressure to the headspace of the gas trap, b) In a gas-liquid contactor, a liquid is brought into contact with a gas, thereby generating a reaction product. c) Discharging the above reaction product through liquid stream B, d) Enabling the flow of liquid stream B through the gas trap and discharging that flow from the gas trap through liquid stream C, wherein the liquid flow is able to flow under the influence of gravity. e) Driving the liquid stream C through the heat exchanger by the driving force generated by the influence of gravity, Includes.

[0025] The following will refer specifically to the drawings, but it is emphasized that the items shown are illustrative and intended solely for the purpose of providing a descriptive overview of various embodiments of the present invention. These drawings are presented to provide what is considered to be the most useful and simplest explanation of the principles and conceptual aspects of the present invention. In this regard, no further structural details of the present invention beyond those necessary for a basic understanding of the present invention are to be shown. This explanation, together with the drawings, will make to those skilled in the art how some embodiments of the present invention can be actually implemented. [Brief explanation of the drawing]

[0026] [Figure 1] This is a schematic diagram of a processing unit according to one embodiment of the present invention, showing that a gas-liquid contactor 1 is connected to a gas trap 2, and the gas trap 2 is further connected to a heat exchanger 3. The gas-liquid contactor 1 and the heat exchanger 3 are positioned at different heights so that the liquid flow can flow from the gas-liquid contactor 1 to the heat exchanger under the influence of gravity, and therefore Hr > Hc. In other words, the heat exchanger 3 is positioned at a lower height than the gas-liquid contactor 1. [Figure 2] This is a schematic diagram of a processing unit according to one embodiment of the present invention, in which a gas-liquid contactor 1, a gas trap, and an economizer are arranged such that the gas trap 2 is at a lower height than both the heat exchanger 3 and the gas-liquid contactor 1, and the heat exchanger 3 is at a lower height than the gas-liquid contactor 1, i.e., Hr > Hc > HL, and the processing unit further comprises a gas-liquid separator 4 connected downstream of the economizer. [Figure 3]This is a schematic diagram of a processing unit according to one embodiment of the present invention, which is provided with a series of means to further reduce the risk of leakage upstream of the economizer. [Figure 4] This is a schematic diagram of a processing unit according to one embodiment of the present invention, the processing unit comprising a gas-liquid separator equipped with a series of safety measures located downstream of the economizer. [Modes for carrying out the invention]

[0027] Herein, the present invention will be described further. The following sections will specify different embodiments of the present invention in more detail. Each of the embodiments described herein may be combined with any other one or more embodiments unless otherwise explicitly indicated. In particular, any feature indicated as preferred or advantageous may be combined with any other one or more features indicated as preferred or advantageous. When describing the compounds of the present invention, the terms used shall be interpreted in accordance with the following provisions unless the context indicates otherwise.

[0028] As used herein, the terms “about” or “approximately” refer to measurable values ​​such as parameters, quantities, or durations, and mean to include variations of + / -10%, preferably + / -5%, more preferably + / -1%, and even more preferably + / -0.1% or less of the expressed value, insofar as it is appropriate for implementation in the disclosed invention. It should be understood that the values ​​referred to by the modifying phrases “about” or “approximately” are themselves specifically and preferably disclosed.

[0029] According to a first aspect, the present invention relates to a processing unit for processing corrosive media such as corrosive liquid streams, basic liquid streams, or acidic liquid streams, which may be at high temperatures, wherein the processing unit It is adapted to bring the liquid from input stream A into contact with a gas such as air or water vapor, and to discharge the liquid stream B, with a height H rA gas-liquid contactor such as a flow-through membrane tower is arranged, A gas trap is positioned to receive liquid stream B and discharge liquid stream C, and is provided with a headspace for capturing gas volume to allow for bubble removal and attenuation of pressure surges in stream B. It is arranged to receive liquid stream C and discharge liquid stream D, and is equipped with a heat exchange means, at a height H c A heat exchanger is positioned, A first vacuum line L1 is fitted to supply negative gauge pressure to the headspace, thereby causing the liquid stream B to be drawn into the gas trap, It is equipped with, The pressure difference is supplied as driving force through the heat exchanger. r >H c That is the case.

[0030] In the context of the present invention, the term “gas-liquid contactor” refers to industrial equipment in which gas and liquid are supplied in contact with each other. Suitable gas-liquid contactors for carrying out the present invention include differential gas-liquid contactors in which mass transfer occurs along the entire length of the contactor and gas-liquid equilibrium is not reached at any point in the equipment, and stepped gas-liquid contactors in which gas-liquid equilibrium is reached at each stage of the equipment and mass transfer occurs only in a portion of the volume of each stage. Examples of differential gas-liquid contactors include drip-film towers, packed towers, bubble towers, spray towers, and gas-liquid agitated tanks. Examples of stepped gas-liquid contactors include tray towers, rotary disc contactors, and Venturi tubes. According to one embodiment of the present invention, the processing unit of any one of the preceding claims is wherein the gas-liquid contactor 1 is a drip-film tower. In a further embodiment of the present invention, the drip-film tower is provided to carry out a chemical reaction, for example, an exothermic hydrolysis / solvation reaction of polyphosphate (PPA), or an endothermic oligomerization / condensation reaction of orthophosphate / pyrophosphate (PA). In a falling membrane tower, PPA or PA is supplied in close contact with the air and / or water vapor present in the tower, which can cause turbulence downstream of the tower, which is harmful to downstream industrial equipment, such as heat exchangers, and can cause leaks. The present invention solves this problem. According to one embodiment of the present invention, a gas-liquid contactor 1 is a reactor configured to receive a reaction reagent, preferably an inorganic oxo acid and / or a salt thereof, more preferably polyphosphate (PPA), and to bring the reaction reagent into contact with water. The present invention significantly reduces the pressure in the heat exchanger 3, and the effects of the presence of gas in the piping are also minimized at the location of the heat exchanger 3.

[0031] By providing a gas trap 2, the pressure in the heat exchanger 3 is typically reduced to 2 to 3 bar, eliminating the need for a pressurized means to move the liquid between the gas-liquid contactor 1 and the heat exchanger 3. Heat exchangers with relatively low operating pressures, such as those made of graphite, benefit most from this invention. Graphite heat exchangers have a maximum operating pressure of approximately 6 to 8 bar (gauge pressure). This invention allows the pressure reaching these heat exchangers to be consistently maintained at less than 50% of the maximum operating pressure (i.e., with minimum to zero pressure spikes). According to this invention, the pressure drop in the heat exchanger 3 can be reduced to less than 3 bar, less than 2 bar, and advantageously, even better, to the range of 0.5 to 1 bar. This dramatically reduces the possibility of leakage and will increase the average time between leaks to several years of normal operation.

[0032] According to the present invention, the gas-liquid contactor 1 is provided to bring a liquid from an input stream A into contact with a gas and discharge a liquid stream B. Depending on the type of liquid stream A that has come into contact with the gas in the gas-liquid contactor, the discharged liquid stream B may be discharged from the gas-liquid contactor at a high temperature. The gas-liquid contactor 1 is provided with a height H according to the present invention. r It is located there.

[0033] According to the present invention, the processing unit further comprises a gas trap 2 arranged to receive a liquid stream B coming from a gas-liquid contactor and discharge a liquid stream C.

[0034] In the context of the present invention, the term “gas trap” refers to an industrial device that, when filled with liquid, is capable of forming a headspace, thereby designed to trap a volume of gas inside. This has been found to provide a means for enabling the attenuation of pressure surges and maintaining the pressure downstream of the gas trap within a predetermined preferred range. A gas trap 2 according to the present invention can take various shapes and configurations, but is not limited to, a siphon, an expansion chamber, a large-diameter tube with a minimum diameter for releasing bubbles, a limiting orifice that creates a lower pressure for generating bubbles, etc. According to one embodiment of the present invention, the gas trap 2 is provided with a headspace for trapping a volume of gas that enables the attenuation of pressure surges in stream B. In the context of the present invention, the headspace can be any assembly adapted to prevent bubbles from advancing further along the unit. For example, if the gas trap 2 is a siphon, the headspace can be a calculated tube to ensure that bubbles advance along the unit without being trapped in the siphon. In this example, the headspace can be provided with a minimum diameter to ensure that the descent rate of the liquid is sufficiently low compared to the rising rate of the bubbles.

[0035] According to a further embodiment of the present invention, the processing unit further comprises one or more tubes that are traced at least partially. In other words, according to this embodiment, one or more components of the unit, for example, one or more tubes connecting the gas-liquid contactor 1 and the gas trap 2, are provided with tracing along their length or at least a portion of their circumference. The tracing is advantageous in simplifying operation by preventing the liquid in the unit from cooling and increasing in viscosity, thereby preventing the line from becoming blocked, for example, by (partial) crystallization of the liquid. This may occur during a sudden shutdown or blockage of the unit. The tracing makes it possible to maintain the temperature of the liquid blocked inside within a specific preferred range until operation can be resumed. The tracing of the tubes can be achieved by means of heating the tubes or a portion thereof with, for example, a conductor, steam or any other heating medium.

[0036] Furthermore, according to the present invention, the processing unit includes a heat exchanger 3 equipped with heat exchange means, which is arranged to receive a liquid stream C and discharge a liquid stream D.

[0037] According to the present invention, the term "heat exchanger" refers to an industrial component provided to facilitate the exchange of heat between, for example, two liquids, two gases, or a gas and a liquid. In particular, according to the present invention, the heat exchanger 3 is provided to exchange heat with the liquid stream C by heat exchange means. Various heat exchange means can be used according to the present invention. In particular, the present invention makes it possible to use heat exchange means including, but is not limited to, graphite carbon, silicon carbide (SiC), silicon dioxide (SiO2), and metals (steel, e.g., stainless steel, copper, aluminum, etc.).

[0038] According to a first aspect of the present invention, the processing unit comprises a first vacuum line L1 adapted to supply negative gauge pressure to the headspace of the gas trap 2, thereby causing the liquid stream B to be drawn into the gas trap 2. In accordance with the present invention, the vacuum line is a tube capable of withstanding negative pressure, connected to a negative pressure supply means such as a vacuum pump. Without such a vacuum line, gas and / or air passing through without the gas trap may cause liquid hammer, potentially resulting in serious damage to the integrity of fragile equipment.

[0039] According to one embodiment of the present invention, the heat exchange means of the heat exchanger includes a material selected from graphite (C), silicon carbide (SiC), and silicon dioxide (SiO2). According to a preferred embodiment of the present invention, the heat exchange means includes graphite. The processing unit according to the present invention makes it possible to use a heat exchanger that includes heat exchange means, such as heat exchange means made of a material selected from graphite (C), silicon carbide (SiC), and silicon dioxide (SiO2), which are particularly susceptible to damage.

[0040] According to the present invention, the heat exchanger has a height H cThe height H of the gas-liquid contactor is positioned such that the pressure difference is supplied as driving force through the heat exchanger. r The height H of the heat exchanger c It is larger than that. In other words, the gas-liquid contactor and heat exchanger are positioned at a height that allows the liquid introduced into the gas-liquid contactor to flow into the heat exchanger under the influence of gravity.

[0041] According to one embodiment of the present invention, the heat exchange means is selected from a tube or tube bundle, one or more plates, disks, or blocks.

[0042] According to the present invention, the liquid stream B discharged from the gas-liquid contactor can be at a temperature higher than the temperature at which the downstream processing unit is designed to operate. Thus, according to the present invention, the reaction can be carried out at a temperature higher than that possible without the present invention. By increasing the temperature of the liquid discharged from the reaction receptor, and conversely, the temperature of the reaction itself, several advantages that are obvious to those skilled in the art become possible, such as the use of cheaper and less reactive chemical species, reduced reagent usage, higher conversion rates, faster reaction times, etc. According to one embodiment of the present invention, liquid stream B and / or liquid stream C have a pH lower than 2 or higher than 12. According to one embodiment of the present invention, liquid stream B and / or liquid stream C have a temperature of 100°C to 300°C, preferably 120°C to 250°C.

[0043] In chemistry, highly reactive species (e.g., acids and bases) such as H2SO4, HNO3, HCl, Cl2, Br2, HBr, F2, and HF are often used to drive organic reactions, mostly at temperatures above 150°C to above 200°C, in the presence of water (e.g., in hydrolysis reactions). Under these conditions, corrosion of the processing unit downstream of the gas-liquid contactor must be avoided, which is a major challenge for the chemical industry. If the processing unit is designed to operate under pressure, i.e., if the processed liquid is supplied at a pressure other than atmospheric pressure, failure of one or more components within the processing unit can have catastrophic consequences. According to one embodiment of the present invention, liquid stream B and / or liquid stream C have a pH lower than 2 or higher than 12.

[0044] According to one embodiment of the present invention, liquid stream B and / or liquid stream C have a temperature of 100°C to 300°C, preferably 120°C to 250°C.

[0045] One aspect of the present invention relates to the use of a gas trap 2 located upstream of a heat exchanger 3 having heat exchange means, wherein the gas trap is used to protect the heat exchange means from pressure changes.

[0046] In a further embodiment, the present invention relates to a method for operating a processing unit described in any one embodiment of the processing unit of the present invention for processing a corrosive liquid, wherein the method is a) Supplying negative gauge pressure to the headspace of the gas trap, b) In a gas-liquid contactor, a liquid is brought into contact with a gas, thereby generating a reaction product. c) Discharging the above reaction product through liquid stream B, d) Enabling the flow of liquid stream B through the gas trap and discharging that flow from the gas trap through liquid stream C, wherein the liquid flow is able to flow under the influence of gravity. e) Driving the liquid stream C through the heat exchanger by the driving force generated by the influence of gravity, Includes.

[0047] In this embodiment, it has been found that it is advantageous to operate the processing unit of the present invention starting from a negative gauge pressure already established in the headspace of the gas trap. In other words, it has been found that it is advantageous to perform processing with the processing unit of the present invention when at least one vacuum line is functioning at the start of operation, i.e., when negative pressure (vacuum) is realized at the location of the gas trap.

[0048] Figure 1 illustrates how the present invention can be carried out, disclosing an embodiment of the present invention in which a gas-liquid contactor 1 is provided to receive a liquid (see input stream A, e.g., the upper position of the contactor), and the liquid is brought into contact with a gas in a drip-membrane tower or the like. Since chemical reactions are either exothermic (requiring cooling) or endothermic (requiring heating), gas-liquid contactors typically include heat exchange means. This is also true when using corrosive, basic, or acidic media in industry, which often need to be diluted with water or a solvent. This dilution is often exothermic, requiring cooling by, for example, vapor generation. In other applications, these media need to be increased in concentration. This is often endothermic, requiring heating by, for example, vapor condensation. In a gas-liquid contactor, chemical reactions may occur between the liquid and the gas, either by bringing the liquid and the gas into contact so as to react in that manner, or by bringing a first liquid into contact with another liquid so as to react in that manner. In either case, in the gas-liquid contactor 1, the liquid is brought into contact with the gas, and the gas and the liquid may react. The gas-liquid contactor 1 is located at a height H from the base on which the processing unit is erected. r It is located at a height H from the base. A gas trap 2 is provided, connected to a gas-liquid contactor 1. The gas trap is connected to the gas-liquid contactor 1 and receives the discharged liquid stream B from the gas-liquid contactor 1. The gas trap 2 is then connected to a heat exchanger 3, which is provided to receive the liquid from the gas trap 2. cIt is located there. Next, the heat exchanger 3 is provided with means for discharging the liquid stream after heat transfer has occurred, thereby discharging the liquid stream D. The heat exchanger 3 and the gas-liquid contactor 1 are adapted, i.e., arranged, so that a liquid stream can flow between these two equipment components under the influence of gravity, i.e., the heat exchanger is gravity-fed. This is so that the pressure difference is supplied as a driving force through the heat exchanger. r >H c This would be possible. Figure 1 also shows a first vacuum line L1 and a second vacuum line L2 connected to a negative pressure supply means, for example, a vacuum pump (not shown). The vacuum lines, in particular the first vacuum line L1, facilitate the suction of liquid into the gas trap 2. The first vacuum line L1 and / or the second vacuum line L2 can be connected to various locations in the processing unit according to the present invention, but are adapted to supply negative pressure to the headspace of the gas trap 2. The first vacuum line L1 and / or the second vacuum line L2 can be connected directly or indirectly to either the gas trap 2 and / or the gas-liquid contactor 1, so as to facilitate the suction of liquid into the gas trap 2 by removing gas and / or air before starting. One or more vacuum lines assist gravity as a driving force for the movement of liquid from the gas-liquid contactor 1 to the heat exchanger 3.

[0049] The term "gravity supply" refers to a system adapted to provide a flow of liquid stream from the gas-liquid contactor 1 to the heat exchanger 3, even in the absence of a first pumping means. According to the present invention, the pumping means may be located downstream of the heat exchanger 3. Pumping means may also be provided at various locations along this path to pump the liquid stream from the gas-liquid contactor 1 to the heat exchanger 3, although the presence of such pumping means would not be necessary to produce the above flow from the gas-liquid contactor 1 to the heat exchanger 3.

[0050] The term “pumping means” refers to means adapted for moving a liquid. Useful pumping means in the context of the present invention are centrifugal pumps, positive displacement pumps, or any other type of fluid pump. The pumps may be driven electrically or via a vapor expander. In preferred embodiments, the pumps used in the context of the present invention are centrifugal pumps, more specifically centrifugal pumps made of metallic materials, and even more specifically centrifugal pumps made of carbon steel or stainless steel lined with PTFE, PFA. Pumping means equipped with a motor connected to a variable frequency drive (VFD) are particularly advantageous.

[0051] The processing of corrosive, basic, and acidic liquid streams in conventional processing equipment, particularly at temperatures above 100°C, is often limited by the design temperature and pressure of one or more pumping means or heat exchangers. If the liquid stream is at a temperature higher than the design temperature of the pumping means, the pump may not function properly and / or may be damaged by the liquid stream. If the pressure of the liquid stream is higher than the design pressure of the heat exchanger, the walls of the heat exchanger may break, allowing the liquid to leak. According to the present invention, by providing a height difference between the gas-liquid separator 1 and the heat exchanger 3, the use of pumping means can be avoided and the heat exchanger can be protected from rapid pressure fluctuations, i.e., pressure spikes, which may be higher than the heat exchanger's design pressure. Gravity feeding systems, such as those according to the present invention, in which the liquid is in contact with the gas, nevertheless have the disadvantage that air intake and air lock can easily occur, and the effects of these can be difficult to mitigate.

[0052] One possible cause of pressure spikes is the intake of air and / or gas, which is minimized here by the presence of a gas trap 2 between the gas-liquid contactor 1 and the heat exchanger 3. That is, the gas trap 2 is provided to allow the intake air to be exhausted. The use of the gas trap 2 and the gravity supply configuration has the synergistic effect of minimizing both overpressure and pressure spikes, thereby making it possible to maintain the pressure in the heat exchanger 3 within a favorable pressure range. Another effect of the gas trap 2 is that if bubbles may form after 1, these bubbles cannot pass through the gas trap 2 toward the equipment 3 and can easily return to equipment 1.

[0053] Therefore, an object of the present invention is to address these drawbacks in industrial units for processing high-temperature liquids and / or corrosive liquids under pressure.

[0054] In the context of this invention, corrosive, basic, or acidic media refer to media capable of damaging industrial equipment based on their chemical properties, such as corrosiveness, basicity, or acidity. Since the reactivity of these media increases with temperature, corrosive, basic, or acidic media at high temperatures are a greater cause of damage to industrial equipment. Damage to industrial equipment includes, for example, loosening / cracking of gaskets and O-rings, perforation of equipment, and failure of moving parts. Damage to heat exchangers due to overpressure of high-temperature and / or corrosive liquids is a particular problem, which is addressed by this invention. Large heat exchange surfaces are preferred in heat exchanger designs, which results in thin heat exchange means, leading to reduced mechanical rigidity and propension to leakage. Furthermore, various materials, while highly advantageous during heat exchange, may not be suitable for manufacturing heat exchange means for heat exchangers. When operating conditions involve high temperature and high pressure, finding suitable heat exchange materials to perform the job becomes a challenge. The present invention provides industrial equipment that enables the processing of high-temperature liquids and / or corrosive liquids in a processing unit equipped with a heat exchanger, which may be made of materials known to be leaky, such as graphite, glass, and SiC.

[0055] In other words, the processing unit according to the present invention provides means for favorably maintaining the pressure within the unit at a pressure lower than the maximum operating pressure of the heat exchanger. In the context of the present invention, the maximum operating pressure of a heat exchanger, or the design pressure of a heat exchanger, is the maximum pressure of the fluid that the heat exchanger can process without damage. The maximum operating pressure of a heat exchanger is set by the manufacturer of the heat exchanger. With respect to a particular type of heat exchanger, the maximum operating pressure is due to the designed pressure limits relating to the components of the heat exchanger and / or the materials from which they are composed.

[0056] Corrosive media, basic media, and acidic media that can be treated by a processing unit as described in accordance with the present invention include any type of ionic liquid containing any type of solvent, for example, inorganic oxoacids (e.g., HNO3, H2SO4, H3PO4) and / or salts thereof and water, metal halogen salts (e.g., LiBr / LiCl...) and water, ammonium salts and water, in particular inorganic oxoacids and / or salts thereof and water, and more specifically, orthophosphate / pyrophosphate (PA) and water in endothermic oligomerization / condensation reactions, or polyphosphate (PPA) and water in exothermic hydrolysis / solvation reactions.

[0057] Figure 2 shows one or more embodiments of the present invention, illustrating a processing unit comprising an economizer 9 and a gas-liquid separator 4. According to the embodiment of the present invention shown in Figure 2, the processing unit comprises a gas-liquid separator 4 positioned to receive a liquid stream D from a heat exchanger, the gas-liquid separator 4 being positioned at the height H of the heat exchanger to allow static pressure in the liquid stream D to avoid its liquid-gas transition. c A height higher than H s It is located at a height H. In this particular exemplary embodiment, the gas trap 2 is at a height H L It is located at H r >H s >H c >H L The height is H. L The gas trap 2 positioned at the gas-liquid separator 4 has been found to be advantageous in combination with any other embodiment of the present invention. r >H s >H c >H L By providing a gas trap 2 positioned in such a manner, it was found that having the gas trap 2 at the lowest point of the unit is advantageous in preventing gas from entering the heat exchanger 3.

[0058] The gas-liquid contactor 1 according to the present invention should be understood as having a number of inlets or outlets necessary for carrying out the present invention. As schematically shown in Figure 2, the gas-liquid contactor receives or can receive multiple input streams of material (e.g., solid or liquid). For example, the gas-liquid contactor 1 can receive an input stream F of preheated material coming from an economizer 9, which has been cooled or preheated by a heat exchange means within the economizer. In other situations, the gas-liquid contactor 1 may be provided with an exhaust port that can be provided to release gases such as water vapor from the gas-liquid contactor.

[0059] In the case of exothermic reactions, the gas-liquid contactor 1 may require cooling. According to one embodiment of the present invention, in order to cool the gas-liquid contactor, a stream of cooling liquid may be supplied to a heat exchanger at the location of the gas-liquid contactor 1 and come into thermal contact with it. The cooling effect can be achieved, for example, by generating steam. In this case, the hot water entering the heat exchanger will be heated by the generation of steam. In other applications, the corrosive, basic, or acidic medium in the gas-liquid contactor 1 may need to be concentrated. This can be done by evaporation of a liquid, such as water or a solvent. Evaporation is often an endothermic reaction that needs to be heated, for example, by condensation of steam. In this case, the steam entering the heat exchanger will be cooled and condensed.

[0060] In Figure 2, the economizer is designed so that the high-temperature liquid discharged from the gas-liquid contactor 1 preheats the liquid to be supplied to the gas-liquid contactor 1, while simultaneously cooling this lower-temperature liquid to be supplied to the gas-liquid contactor 1 and discharging the stream from the gas-liquid contactor 1. That is, according to one embodiment of the present invention, the processing unit includes a heat exchanger 3 being part of an economizer 9 adapted to thermally contact the liquid stream E to be supplied to the gas-liquid contactor 1 with the liquid stream C. The advantage of this embodiment is that heat can be efficiently reused, thereby providing a more efficient processing unit.

[0061] In a particular embodiment disclosed in Figure 2, a gas-liquid separator 4, also known as a flash drum, is further added to evaporate the steam stream, such as water vapor, from the gas-liquid separator from the economizer 9, thereby lowering the temperature of the economizer discharge stream D by evaporative cooling and obtaining a lower temperature gas-liquid separator discharge stream. In the gas-liquid separator 4, the pressure of the economizer discharge stream 5 expands to a lower pressure, resulting in, for example, water evaporating and the liquid remaining behind. The stream D is cooled by the evaporation of the solvent. More specifically, the gas-liquid separator 4 provides an additional cooling effect to cool the corrosive stream, basic stream, or acidic liquid stream originating from the gas-liquid contactor 1 before it reaches further processing stages.

[0062] In one embodiment of the present invention, as also shown in Figure 2, the use of a gas-liquid separator is provided downstream of the heat exchanger 3 and at a height H higher than the height of the heat exchanger to generate static pressure at the discharge of the heat exchanger 3. s It is positioned as follows. An advantage of this embodiment is that if the temperature of stream D is too high, the fixed height supplies a pressure exceeding the vapor pressure of the liquid in liquid stream D, thus avoiding a flushing effect on the liquid stream. Since graphite is very sensitive to all kinds of evaporation on its surface, evaporation of the liquid in the graphite equipment is also avoided. In other words, this configuration provides a sustainable design that is suitable for all process conditions, such as excessively high temperatures and excessively low pressures in different operating modes.

[0063] Therefore, one embodiment of the present invention provides the use of a gas-liquid separator 4 in a processing unit for processing a corrosive medium, the processing unit is It is adapted to bring the liquid from input stream A into contact with the gas and discharge the liquid stream B, at a height H r A gas-liquid contactor 1 is positioned, It is arranged to receive liquid stream C and discharge liquid stream D, and is equipped with a heat exchange means, at a height H c A heat exchanger 3 is positioned, It is equipped with, The pressure difference is supplied as driving force through the heat exchanger. r >H c The gas-liquid separator 4 is located downstream of the heat exchanger 3 and is positioned at a height H higher than the height of the heat exchanger to generate static pressure at the heat exchanger discharge in the liquid stream D in order to avoid the liquid-gas transition. s It is located there.

[0064] According to one embodiment, a processing unit for processing a corrosive medium is provided, and the processing unit is It is adapted to bring the liquid from input stream A into contact with the gas and discharge the liquid stream B, at a height H r A gas-liquid contactor 1 is positioned, It is arranged to receive liquid stream C and discharge liquid stream D, and is equipped with a heat exchange means, at a height H c A heat exchanger 3 is positioned, It is equipped with, The pressure difference is supplied as driving force through the heat exchanger. r >H c The gas-liquid separator 4 is located downstream of the heat exchanger 3 and is positioned at a height H higher than the height of the heat exchanger to generate static pressure at the heat exchanger discharge in the liquid stream D in order to avoid the liquid-gas transition. s It is located there.

[0065] According to another embodiment of the above-described embodiment, the processing unit further comprises a vacuum line L2 connected to a gas-liquid contactor 1 and adapted to supply negative gauge pressure to the gas-liquid contactor 1, thereby resulting in the suction of input stream A to the gas-liquid contactor 1. In certain embodiments, this vacuum line is connected to a gas-liquid separator 4.

[0066] According to another embodiment of the present invention, the processing unit is A first pumping means 5 is adapted to receive the liquid stream C and pump the liquid stream C toward the heat exchanger 3, A pressure measuring means 6 is provided to measure the pressure of the liquid stream C that is pumped downstream of the control valve 7, in the direction of the heat exchanger 3, A pressure control valve 7 is located downstream of the first pumping means 5 and pressure measuring means 6, and is provided to regulate the flow of liquid stream C to the heat exchanger 3. A pressure control means 8 is configured to maintain the pressure of the liquid stream C within a predetermined pressure range by communicating with the first pumping means 5, the pressure measuring means 6, and the pressure control valve 7, and by activating the pressure control valve 7 and / or the first pumping means 5 based on the pressure measuring means 6. It is equipped with.

[0067] This embodiment has been found to be advantageous in that it provides further control over the pressure reaching the heat exchanger 3, thereby further minimizing the risk of leakage within the heat exchanger. The presence of the first pumping means 5 and the gas trap 2 reduces the intake of air in the liquid and minimizes the amount of bubbles reaching the heat exchanger 3. Various pumps can be used according to embodiments of the present invention, but nevertheless, according to a preferred further embodiment of the present invention, the first pumping means 5 comprises a motor connected to a variable frequency drive (VFD) adapted to be actuated by a pressure control means 8. The first pumping means according to this embodiment allows for fine adjustment of the motor, thereby providing a method for gradually increasing or decreasing the motor RPM for the first pumping means. In this way, pressure spikes are reduced and the pressure within the heat exchanger is further maintained within its operating pressure.

[0068] Figure 3 shows one or more embodiments of the present invention, in which a series of means are provided to further reduce the risk of leakage upstream of the economizer. In particular, Figure 3 shows an embodiment disclosed in Figure 2, in which the processing unit is A first pumping means 5 is adapted to receive the liquid stream C and pump the liquid stream C toward the heat exchanger 3 (in this case, the economizer 9), Regarding the direction of the heat exchanger 3, there is a pressure measuring means 6 (also referred to as PIC) provided to measure the pressure of the liquid stream C that is pumped downstream of the control valve 7, A pressure control valve 7 is located downstream of the first pumping means 5 and pressure measuring means 6, and is provided to regulate the flow of liquid stream C to the heat exchanger 3. A pressure control means 8 is configured to communicate with the first pumping means 5, the pressure measuring means 6, and the pressure control valve 7, and to operate the pressure control valve 7 and / or the first pumping means 5 based on the pressure measuring means 6, thereby maintaining the pressure of the liquid stream C within a predetermined pressure range. It also has the following features.

[0069] Figure 4 shows one embodiment of the present invention, in which the processing unit comprises a gas-liquid separator equipped with a series of safety measures located downstream of the economizer. In particular, according to one embodiment of the present invention, the gas-liquid separator 4 is further supplemented with a control system, also called safety measures, for monitoring and opening / closing the streams entering and leaving the gas-liquid separator 4. Referring again to Figure 4, such safety measures are: A pressure device, also known as a PIC, for measuring the pressure of the gas-liquid separator 4, A valve unit, also known as a PCV, is used for the steam G to the steam condenser between the gas-liquid separator 4 and the steam condenser 12. It is equipped with.

[0070] If the vacuum in the gas-liquid separator 4 is insufficient due to insufficient solvent evaporation and therefore insufficient cooling, the valve unit opens to control the pressure in the gas-liquid separator 4 accordingly and thus stimulate the evaporation of the solvent. This evaporative cooling causes the solvent to cool. The resulting solvent vapor moves from the gas-liquid separator to the vapor condenser 12 via the vapor stream G. This ultimately prevents the medium from being supplied to the suction line 10, also known as the supply line, of the second pumping means 11, which is too hot and / or too high in pressure. The safety measures may optionally further include a temperature device, also known as a TIC, for measuring the temperature of the vapor stream G. If the temperature of the medium is too high, for example, above the design temperature of the second pumping means 11, the valve unit closes. This additional safety measure now protects the second pumping means from operating above its design temperature under any circumstances. [Examples]

[0071] Example 1 - Production of hydrochloric acid One example is the absorption of HCl into water to produce hydrochloric acid. Cooling of the absorbed medium is carried out using a graphite plate heat exchanger, and since leakage of HCl must always be avoided for environmental and passerby safety reasons, a vapor-generating absorber is placed below the graphite plate / disk heat exchanger so that the generated hydrochloric acid (typically 30-50% HCl in water) is cooled without a pump, thus avoiding high pressure on the graphite plate / disk heat exchanger. [Explanation of Symbols]

[0072] 1. Gas-liquid contactor 2 gas traps 3 Heat exchanger 4 Gas-liquid separator 5. First pumping means 6. Pressure measuring means 7 Control valve 8. Pressure control means 9 Economizer 10 Pump suction lines 11 Second pumping means 12. Steam condenser A Input stream to gas-liquid contactor B. Discharge liquid stream from gas-liquid contactor C. Exhaust liquid stream from gas trap D. Exhaust liquid stream from heat exchanger Liquid stream to E Economizer Liquid stream from economizer to gas-liquid contactor G Steam to the steam condenser X Liquid from gas-liquid separator L1 First Vacuum Line L2 Second Vacuum Line H c Height of the heat exchanger H r Height of gas-liquid contactor H s Height of the gas-liquid separator H L gas trap height

Claims

1. A processing unit for processing a corrosive medium, wherein the processing unit comprises, It is adapted to bring the liquid from input stream A into contact with the gas and discharge the liquid stream B, at a height H r A gas-liquid contactor (1) is positioned at, A gas trap (2) is positioned to receive the liquid stream B and discharge the liquid stream C, and is provided with a headspace for capturing the volume of gas that allows for the removal of bubbles and the attenuation of pressure surges in stream B. It is arranged to receive the liquid stream C and discharge the liquid stream D, and is equipped with a heat exchange means, with a height H c A heat exchanger (3) is positioned, A first vacuum line L is adapted to supply negative gauge pressure to the headspace, thereby causing the liquid stream B to be drawn into the gas trap (2). 1 and, It is equipped with, The pressure difference is supplied as driving force through the heat exchanger. r >The aforementioned H c That is, Processing unit.

2. The heat exchanger is positioned to receive the liquid stream D from the heat exchanger, and the height H of the heat exchanger is positioned to allow static pressure in the liquid stream D in order to avoid the liquid-gas transition. c A height higher than H s The processing unit according to claim 1, further comprising a gas-liquid separator (4) positioned at [location].

3. The heat exchange means of the heat exchanger comprises graphite (C), silicon carbide (SiC), and silicon dioxide (SiO 2 The processing unit according to claim 1 or 2, comprising a material selected from ).

4. The processing unit according to any one of claims 1 to 3, wherein the heat exchange means includes graphite.

5. A second vacuum line L connected to the gas-liquid contactor (1) and adapted to supply a negative gauge pressure to the gas-liquid contactor (1), thereby effecting suction of the input stream A into the gas-liquid contactor (1). 2 The processing unit according to any one of claims 1 to 4, further comprising this. 2

6. The first vacuum line L 1 and / or the second vacuum line L 2 The processing unit according to any one of claims 1 to 5, which is connected to the gas-liquid separator (4).

7. The processing unit according to any one of claims 1 to 6, further comprising one or more tubes that are at least partially traced.

8. The processing unit according to any one of claims 1 to 7, wherein the heat exchange means is selected from a tube or tube bundle, or one or more plates.

9. The gas trap (2) has a height H L It is located at H r >H c >H L The processing unit according to any one of claims 1 to 8.

10. The processing unit according to any one of claims 1 to 9, wherein the gas-liquid contactor (1) is a flow-through membrane tower.

11. The processing unit according to any one of claims 1 to 10, wherein the gas-liquid contactor is a reactor configured to receive a reaction reagent, preferably an inorganic oxoacid and / or a salt thereof, more preferably polyphosphate (PPA), and to bring the reaction reagent into contact with water.

12. A first pumping means (5) is provided, which is configured to receive the liquid stream C and pump the liquid stream C toward the heat exchanger (3), A pressure measuring means (6) is provided to measure the pressure of the liquid stream C which is pumped downstream of the control valve (7) in the direction of the heat exchanger (3), A pressure control valve (7) is located downstream of the first pumping means (5) and the pressure measuring means (6) and is provided to adjust the flow of the liquid stream C to the heat exchanger (3), A pressure control means (8) is configured to communicate with the first pumping means (5), the pressure measuring means (6), and the pressure control valve (7), and to operate the pressure control valve (7) and / or the first pumping means (5) based on the pressure measuring means (6), thereby maintaining the pressure of the liquid stream C within a predetermined pressure range. The processing unit according to any one of claims 1 to 11, further comprising:

13. The processing unit according to claim 12, wherein the first pumping means (5) comprises a motor connected to a variable frequency drive (VFD) adapted to be actuated by the pressure control means (8).

14. The processing unit according to any one of claims 1 to 13, wherein the heat exchanger (3) is part of an economizer (9) adapted to bring a liquid stream E to be supplied to the gas-liquid contactor (1) into thermal contact with the liquid stream C.

15. Use of a gas trap (2) positioned upstream of a heat exchanger (3) having heat exchange means, wherein the gas trap (2) is used to protect the heat exchange means from pressure changes.

16. The use of a gas-liquid separator (4) in a processing unit for processing a corrosive medium, wherein the processing unit is It is adapted to bring the liquid from input stream A into contact with the gas and discharge the liquid stream B, at a height H r A gas-liquid contactor (1) is positioned at, It is arranged to receive the liquid stream C and discharge the liquid stream D, and is equipped with a heat exchange means, with a height H c A heat exchanger (3) is positioned, It is equipped with, The pressure difference is supplied as driving force through the heat exchanger. r >The aforementioned H c The gas-liquid separator (4) is located downstream of the heat exchanger (3), and is positioned at a height H higher than the height of the heat exchanger to generate static pressure in the liquid stream D in order to avoid the liquid-gas transition. s Located in, use.

17. A method for operating a processing unit according to any one of claims 1 to 14 for processing a corrosive liquid, wherein the method is: a) Supplying negative gauge pressure to the headspace of the gas trap (2), b) In a gas-liquid contactor (1), a liquid is brought into contact with a gas, thereby generating a reaction product. c) Discharging the reaction product through liquid stream B, d) enabling the flow of liquid stream B through the gas trap (2) and discharging the flow from the gas trap through liquid stream C, wherein the liquid flow is able to flow under the influence of gravity, e) Driving the liquid stream C through the heat exchanger by the driving force generated by the influence of gravity, including, method.

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