Method and system for treating process fluid

Abstract

The present invention relates to a method and a system for treating a process fluid and, more specifically, to a method and a system for treating a process fluid, the method and the system having improved operation stability, when recovering waste heat from a process fluid, by employing a condenser designed to respond to the phase of the process fluid, which changes according to whether steam for recovering waste heat is generated.

Description

Process fluid treatment method and system

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority from Korean Patent Application No. 10-2023-0189475, filed December 22, 2023, the entire contents of which are incorporated herein by reference.

[0003] Technology field

[0004] The present invention relates to a process fluid treatment method and system, and more particularly, to a process fluid treatment method and system thereof that improves operational stability by introducing a condenser designed to respond to the phase of a process fluid that varies depending on whether steam is generated for waste heat recovery in a process of recovering waste heat from the process fluid.

[0005] Petrochemical processes consume significant energy to produce products, and this energy is either discarded or reused. Steam, the energy source for these processes, is typically generated using boilers from the combustion heat of hydrocarbon fuels. However, this process is expensive and releases carbon dioxide into the atmosphere through combustion, contributing to global warming. Therefore, waste heat utilization is emerging as a way to reduce steam usage within the process to reduce carbon emissions and lower the manufacturing costs of petrochemical products.

[0006] Typically, petrochemical products are manufactured through processes involving reaction, separation, and refining. When the bottom of the column where these processes are performed is heated using steam, high-temperature process fluids are generated at the top of the column. These high-temperature fluids can serve as waste heat, and a large amount of heat is wasted as they are cooled through heat exchange with cooling water in heat exchangers such as condensers and coolers. The heated cooling water then flows into a cooling tower, where it dissipates heat and is cooled before being fed back to the heat exchanger. The heat released during this cooling process can be considered waste heat within the process.

[0007] To utilize waste heat within the process, boiler feed water is heat-exchanged with high-temperature process fluid to generate steam, which is then utilized. Meanwhile, the process fluid, from which waste heat has been recovered, undergoes a series of processes, either being recycled back to the column or fed into subsequent processes (e.g., reaction or purification processes).

[0008] Specifically, the high-temperature process fluid discharged to the top of the column is converted into a two-phase stream of vapor and liquid due to heat exchange with boiler feedwater during steam generation, and this is condensed through a heat exchanger such as a condenser and then refluxed into the column. However, if steam generation is interrupted during the process due to a failure of the steam generation system for waste heat recovery including the evaporator at the front end of the condenser, there is a problem that the stability risk of the condenser significantly increases as the conditions such as phase change and heat amount of the process fluid stream fed into the condenser change.

[0009] The problem to be solved by the present invention is to provide a process fluid treatment method and system that improves process stability by separating and discharging a process fluid stream discharged from an evaporator according to phase in a process of recovering waste heat from a high-temperature process fluid generated in a petrochemical process in order to solve the problem mentioned in the background technology of the above invention, and introducing a condenser designed to respond to the state of the process fluid that changes depending on whether steam is generated for waste heat recovery.

[0010] However, the problems that the present invention seeks to solve are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the description below.

[0011] According to one embodiment of the present invention for solving the above problem, the present invention provides a method for treating a process fluid, comprising: a step of supplying a vapor phase process fluid stream from a waste heat source to an evaporator, converting the vapor phase process fluid into a two-phase process fluid through heat exchange, and separately discharging the vapor phase first process fluid stream and the liquid phase second process fluid stream from a rear end of the evaporator; a step of supplying the vapor phase first process fluid stream to one region of a condenser having a front-end head having a partition wall to separate the interior into two regions, and supplying the liquid phase second process fluid stream to the other region; and a step of condensing the vapor phase first process fluid stream and cooling the liquid phase second process fluid stream through heat exchange in the condenser.

[0012] In addition, according to one embodiment of the present invention, a process fluid treatment system is provided, including: an evaporator that generates steam using a gaseous process fluid stream supplied from a waste heat source as a heat source; a first line connected to an upper portion of a rear end of the evaporator and transporting a first gaseous process fluid stream discharged from the evaporator; a second line connected to a lower portion of the rear end of the evaporator and transporting a second liquid process fluid stream discharged from the evaporator; a condenser connected to the first line and the second line and exchanging heat with a refrigerant the first gaseous process fluid stream and the second liquid process fluid stream supplied from the evaporator; and a condenser drum connected to the condenser and collecting the heat-exchanged first process fluid stream and the second process fluid stream.

[0013] In addition, the process fluid treatment system may include a front-end head of the condenser having a partition wall to separate the interior into two regions, one region of the condenser front head being connected to the first line, such that a first process fluid stream in a gaseous state supplied from the evaporator is condensed through heat exchange, and the other region of the condenser front head being connected to the second line, such that a second process fluid stream in a liquid state supplied from the evaporator is cooled through heat exchange.

[0014] According to the process fluid treatment method and system of the present invention, in a petrochemical process including a system for recovering waste heat by generating steam through heat exchange from a high-temperature process fluid, which is a waste heat source, excellent process stability can be secured regardless of conditions such as phase change and heat amount of the process fluid stream, which change significantly depending on whether steam is generated.

[0015] Specifically, the two-phase process fluid stream discharged from the evaporator during steam generation is separated into a gaseous stream and a liquid stream, respectively, and these are then injected into two separate areas of a condenser equipped with a baffle at the front head for processing, thereby improving process stability.

[0016] In addition, the process fluid treatment method and system according to the present invention can improve process stability by using a condenser having a baffle in the front head, thereby responding to phase changes and heat amounts of a process fluid stream that vary greatly depending on whether steam is generated, with only one condenser.

[0017] The effects that can be obtained from this invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by those skilled in the art to which the present invention pertains from the description below.

[0018] Figure 1 is a schematic diagram of a process fluid treatment process according to one embodiment of the present invention.

[0019] Figure 2 is a schematic diagram of a process fluid treatment process according to Comparative Example 1.

[0020] Figure 3 is a schematic diagram of a process fluid treatment process according to Comparative Example 2.

[0021] The terms or words used in the description and claims of the present invention should not be interpreted as limited to their usual or dictionary meanings, but should be interpreted as meanings and concepts that conform to the technical idea of ​​the present invention, based on the principle that the inventor can appropriately define the concept of the term to explain his or her own invention in the best way.

[0022] In connection with the description of the drawings, similar reference numerals may be used for similar or related components.

[0023] The singular form of a noun corresponding to an item may include one or more of said items, unless the relevant context clearly indicates otherwise.

[0024] In this disclosure, each of the phrases "A or B", "at least one of A and B", "at least one of A or B", "A, B, or C", "at least one of A, B, and C", and "at least one of A, B, or C" may include any one of the items listed together in the corresponding phrase, or all possible combinations thereof.

[0025] The term “and / or” includes any combination of a plurality of related described elements or any one of a plurality of related described elements.

[0026] Terms such as "first," "second," or "first" or "second" may be used simply to distinguish one component from another and do not qualify the components in any other respect (e.g., importance or order).

[0027] In addition, terms such as 'front', 'rear', 'top', 'bottom', 'side', 'left', 'right', 'upper', and 'lower' used in this application are defined based on the drawings, and the shape and position of each component are not limited by these terms.

[0028] The terms “include” or “have” are intended to specify the presence of a feature, number, step, operation, component, part or combination thereof described in the present disclosure, but do not preclude the presence or addition of one or more other features, numbers, steps, operations, components, parts or combinations thereof.

[0029] When a component is said to be “connected,” “coupled,” “supported,” or “in contact with” another component, this includes not only cases where the components are directly connected, coupled, supported, or in contact, but also cases where the components are indirectly connected, coupled, supported, or in contact through a third component.

[0030] When we say that a component is “on” another component, this includes not only cases where the component is in contact with the other component, but also cases where there is another component between the two components.

[0031] In addition, the terms "about", "substantially", etc. used herein are used in the sense of or close to the numerical value when manufacturing and material tolerances inherent to the meanings mentioned are presented, and are used to prevent unscrupulous infringers from unfairly using the disclosure contents in which exact or absolute numerical values ​​are mentioned to aid understanding of the present invention.

[0032] The term "stream" as used herein may refer to the flow of fluid within a process, or may refer to the fluid itself flowing within a pipe. Specifically, the stream may refer to both the fluid itself flowing within the pipe connecting each device and the flow of the fluid. Furthermore, the fluid may include one or more components of gas, liquid, and solid.

[0033] The term "upper" as used herein, unless otherwise specified, refers to a point 0% to 20% in height downward from the top of the device, and may specifically refer to the top (top). In addition, the term "lower" refers to a point 80% to 100% in height downward from the top of the device, and may specifically refer to the bottom (bottom).

[0034] Additionally, “pressure” as referred to herein means gauge pressure measured based on atmospheric pressure.

[0035] Referring to FIG. 1, the process fluid treatment method according to the present invention can be performed using a process fluid treatment system including a plurality of heat exchangers for the process fluid after waste heat recovery.

[0036] A process fluid treatment method according to one embodiment of the present invention includes the steps of: supplying a gaseous process fluid stream (10) from a waste heat source to an evaporator (200), converting the gaseous process fluid into a two-phase process fluid through heat exchange, and separately discharging the gaseous first process fluid stream (11) and the liquid second process fluid stream (12) from the rear end of the evaporator (200); supplying the gaseous first process fluid stream (11) to one region of a condenser (300) having a front-end head with a partition (A) to separate the interior into two regions, and supplying the liquid second process fluid stream (12) to the other region; and condensing the gaseous first process fluid stream and cooling the liquid second process fluid stream through heat exchange in the condenser (300).

[0037] In general, in order to recycle waste heat generated in a petrochemical process, as illustrated in FIG. 2, instead of directly condensing the top discharge stream (10) of a column (100) in a condenser (300), an evaporator (200) is installed in front of the condenser to recover a portion of the waste heat of the column top discharge stream (10). In such a waste heat recovery system, boiler feed water (BFW) having a lower temperature than the column top discharge stream (10) is injected into the evaporator (200) to receive the heat source of the column top discharge stream (10), thereby partially vaporizing the boiler feed water to generate steam (20), and the steam (20) generated in the evaporator (200) ultimately generates steam at a desired pressure through a pressurization system (250).

[0038] However, in a process fluid treatment system including a waste heat recovery process, the waste heat of the column top discharge stream (10) may not be recovered through the evaporator (200) in some cases. For example, if the steam balance between the process fluid treatment system according to the present invention (i.e., the steam source) and an external system (i.e., the steam user) changes, the required steam production amount may change or steam production may be stopped, and at this time, the supply of boiler feedwater (BFW) to the evaporator may be stopped. In addition, if the pressurization system (250) fails to produce steam, the supply of boiler feedwater (BFW) may be temporarily stopped.

[0039] Meanwhile, in a process including a waste heat recovery system, the process fluid from which waste heat has been recovered is supplied to a condenser (300), condensed, and then refluxed back to the column (100). At this time, the condenser (300) and the condenser drum (350) require temperature control to an optimal temperature suitable for the process characteristics, and the temperature control can be controlled by the flow rate of cooling water (CW) introduced into the condenser. In addition, the temperature of the stream discharged from the condenser and the temperature inside the condenser drum can be the same. More specifically, when operating as a partial condenser, the process fluid stream with the same vapor fraction can be discharged regardless of the change in the stream introduced into the condenser by controlling the temperature. On the other hand, when operating as a full condenser, if the temperature range suitable for the process characteristics is exceeded, problems in the stability of the process operation, such as corrosion, precipitation, and polymerization, may occur.

[0040] However, depending on whether the evaporator (200) is in operation, the operating range of the condenser (300) varies greatly. For example, when the total heat amount of the column top discharge stream (10) is condensed is 100%, in a system where the evaporator (200) condenses about 30% to 80% of the heat amount and the condenser (300) condenses the remaining 20% ​​to 70% of the heat amount, when the operation of the evaporator (200) is stopped, the condenser (300) must respond to a wide range of heat amounts between 20% and 100% with the same device for condensing the column top discharge stream (10). In this way, even though the phase change and required heat amount of the process fluid stream flowing into the condenser vary greatly depending on whether the evaporator is in operation, when a conventional condenser responds to a wide range of operating conditions as shown in FIG. 2, the thermal / mechanical stability of the condenser may be problematic.

[0041] Therefore, a process fluid treatment method and system that enables stable operation regardless of the evaporator's operation in a process fluid treatment system including a waste heat recovery process is needed. More specifically, a method and system that enables stable operation of the condenser even when the evaporator is interrupted is required. Therefore, the present invention provides a process fluid treatment method and system that address the aforementioned issues.

[0042] The above waste heat source may be a high-temperature process fluid (10) generated in a column (100) where various processes such as reaction, separation, and purification are performed during the manufacture of petrochemical products. The temperature of this high-temperature process fluid (10) may vary depending on the conditions of each process, and may be in the range of approximately 50°C to 250°C, and specifically 70°C to 200°C.

[0043] Meanwhile, since processing the process fluid without separate heat recovery is not desirable from an energy perspective, recovering the heat of the waste heat source, i.e., the high-temperature process fluid, and utilizing the recovered heat in other processes requiring heat is essential for reducing the energy consumption of the entire process.

[0044] To this end, first, the high-temperature process fluid stream (10) and boiler feed water (BFW) for steam generation can be supplied to the evaporator (200). The process fluid stream (10) is heat-exchanged with the boiler feed water (BFW) in the evaporator (200), so that the heat of the process fluid can be transferred to the boiler feed water. In addition, the boiler feed water (BFW) can be a feed for steam generation for waste heat utilization. Specifically, the boiler feed water vaporized by the heat transferred from the process fluid in the evaporator (200) can be converted into steam (20).

[0045] The steam (20) discharged from the above evaporator (200) can be post-processed using a pressurization system (250) to compress it to high temperature and high pressure, and such high temperature and high pressure steam can be used as an energy source for various petrochemical processes. Here, the pressurization system (250) may be a mechanical vapor recompression (MVR) system equipped with a device such as one or more stages of a compressor (CP) and / or a blower, or a thermal vapor recompression (TVR) system equipped with a device such as an ejector. The pressurization system (250) may be, for example, an assembly in which two or more compressors are combined, or a compression unit including one or more compressors, but is not limited thereto.

[0046] According to one embodiment of the present invention, waste heat can be recovered by supplying water, which is boiler feed water (BFW), to the evaporator (200) to generate steam (20) through heat exchange with the process fluid stream (10). The evaporator (200) is a device that is connected to a column (100) from which a waste heat source is discharged and transfers waste heat from the process fluid to the boiler feed water to discharge steam.

[0047] The above evaporator (200) is a type of heat exchanger commonly used in petrochemical processes, and the heat exchanger applicable to the present invention may be a shell and tube type, and a plate type or falling film evaporator type may also be used to increase heat exchange efficiency, but is not limited thereto.

[0048] Specifically, since the process fluid may have different fluid properties such as its composition and temperature, the temperature and pressure conditions of the boiler feedwater may be different accordingly. In the evaporator (200), liquid boiler feedwater (BFW), for example, refrigerant having a temperature of 40°C to 150°C, specifically 60°C to 120°C, may be supplied and circulated under conditions of a pressure of 1 to 20 bar, specifically 2 to 10 bar, and a flow rate of 1 ton / hr to 10,000 ton / hr, specifically 10 ton / hr to 1,000 ton / hr. In addition, a high-temperature process fluid stream (10) supplied from a waste heat source is introduced into the evaporator (200) through which the boiler feedwater (BFW) flows, thereby vaporizing the boiler feedwater (BFW) through heat exchange.

[0049] Specifically, the initial temperature of the process fluid stream (10) flowing into the evaporator (200) (i.e., the temperature of the waste heat source) may be 50°C to 250°C, specifically 70°C to 200°C. When a high-temperature gaseous process fluid stream (10) supplied from a waste heat source flows into the evaporator (200), the boiler feedwater (BFW) may absorb heat from the process fluid stream and be vaporized through mutual heat exchange. At this time, in order to generate steam while maintaining the temperature difference with the process waste heat within an appropriate range, it is preferable to control the temperature difference between the boiler feedwater (BFW) and the waste heat source to 5°C to 30°C, specifically 5°C to 20°C.

[0050] The flow rate of the process fluid stream (10) flowing into the evaporator (200) is not particularly limited, but may be, for example, 1 Ton / hr to 10,000 Ton / hr, specifically 10 Ton / hr to 5,000 Ton / hr, and more specifically 20 Ton / hr to 1,000 Ton / hr. The process fluid that has exchanged heat with boiler feed water (BFW) in the evaporator (200) may flow out of the evaporator (200) at a temperature lower than the initial temperature, for example, in the range of 50°C to 200°C. At this time, the process fluid that has been converted into a vapor-liquid two-phase as the temperature is lowered due to the heat exchange is separated and discharged as a first process fluid stream (11) in a gaseous state and a second process fluid stream (12) in a liquid state from the upper and lower portions of the rear end of the evaporator (200), respectively. Meanwhile, in the case where the supply of boiler feedwater to the evaporator (200) is interrupted, only the first process fluid stream (11) in the gas phase may be discharged through the upper portion of the rear end of the evaporator (200). In addition, the temperatures of the first process fluid stream (11) in the gas phase and the second process fluid stream (12) in the liquid phase discharged from the evaporator (200) are the same, and may be, for example, 50°C to 200°C, specifically 50°C to 180°C.

[0051] Typically, petrochemical plants operate multiple heat exchangers to cool or condense high-temperature process fluids generated in various process columns, while simultaneously recovering heat. During this process, some or all of the recovered process fluid is condensed and then refluxed back into the columns for reuse within the process. However, the heat recovery process presents a risk of increased process stability depending on the phase change conditions of the process fluid entering the heat exchanger, such as the condenser.

[0052] Specifically, as shown in FIG. 2, when a two-phase stream (11+12) of vapor and liquid is introduced in a mixed state into a condenser (300) connected to the rear end of an evaporator, mechanical damage may occur to the front-end head of the condenser into which the process fluid stream is introduced, liquid may accumulate in the front head of the condenser, and damage to the tube sheet may occur, thereby lowering process stability.

[0053] Accordingly, the process fluid treatment method and system according to the present invention connects an evaporator to a waste heat source to vaporize boiler feedwater through a high-temperature process fluid to recover heat, and separates and discharges the process fluid converted into a two-phase vapor-liquid due to the heat recovery and processes each by injecting it into a condenser having an individually separated space in the front head, thereby ensuring excellent process stability regardless of whether steam is generated, even with only one condenser.

[0054] The first process fluid stream (11) in the gas phase and the second process fluid stream (12) in the liquid phase separated and discharged from the above evaporator (200) are each independently supplied to the condenser (300).

[0055] According to one embodiment of the present invention, the condenser (300) may have a structure in which a partition wall (A) is provided on the front-end head, thereby dividing the interior into two regions. A vapor-state process fluid stream (11) may be introduced into one region of the front head divided into two regions by the partition wall (A), and a liquid-state process fluid stream (12) may be introduced into the other region.

[0056] In addition, when vapor and liquid are separated in a two-phase stream, since the mass fraction of the liquid is about 70% or more but the volume fraction is less than about 5%, it may be preferable that the partition wall (A) be provided so that one region into which the vapor stream flows (i.e., the vapor region) has a larger volume than the other region into which the liquid stream flows (i.e., the liquid region). For example, the volume ratio of the vapor region and the liquid region may be 2:1 to 20:1, specifically 3:1 to 10:1, and more specifically 5:1 to 10:1.

[0057] Specifically, as shown in FIG. 1, by using a condenser (300) having a partition wall (A) at the front-end head, the first process fluid stream (11) in the gas phase can be supplied to one area of ​​the front head of the condenser (300) and condensed through heat exchange, and the second process fluid stream (12) in the liquid phase can be supplied to another area of ​​the front head of the condenser (300) and cooled through heat exchange.

[0058] For example, the condenser may be provided with a first tube in one region and a second tube in another region, and may perform heat exchange between the first process fluid stream (11) in the gas phase supplied to the first tube and the refrigerant (CW) supplied to the shell, and heat exchange between the second process fluid stream (12) in the liquid phase supplied to the second tube and the refrigerant (CW), in separate regions, respectively.

[0059] In this way, by providing a partition (A) at the front-end head of the condenser (300), the space into which vapor and liquid are injected within the condenser can be separated, so that process fluids of different phases can be injected into each space, and thus, stable operation is possible without mixing vapor and liquid with only one condenser. In addition, there is an advantage in that condensation of gaseous process fluid and cooling of liquid process fluid can be performed simultaneously. Furthermore, the temperature control of the condenser drum (350) described later can be made easier.

[0060] In addition, the temperature of the first process fluid stream (11) in the gas phase flowing into the condenser (300) having a baffle in the front head may be 50°C to 200°C, specifically 50°C to 180°C, and the temperature of the second process fluid stream (12) in the liquid phase may be 50°C to 200°C, specifically 50°C to 180°C. In addition, the temperature of the process fluid stream (13) discharged from the condenser (300) may be 20°C to 150°C, specifically 20°C to 100°C.

[0061] In addition, as the refrigerant (CW) of the condenser (300), cooling water of, for example, 10°C to 50°C, specifically 20°C to 40°C, can be supplied and circulated under the conditions of a pressure of 1 bar to 20 bar, specifically 2 bar to 10 bar, and a flow rate of 1 Ton / hr to 1,000,000 Ton / hr, specifically 1 Ton / hr to 100,000 Ton / hr.

[0062] The condenser (300) provided at the rear end of the above evaporator (200) may include a condenser commonly used in petrochemical processes. The condenser applicable to the present invention may be a shell and tube type, and a plate type or falling film evaporator type may also be used to increase heat exchange efficiency, but is not limited thereto.

[0063] Meanwhile, the mass flow rate ratio of the first process fluid stream (11) in the gas phase and the second process fluid stream (12) in the liquid phase, which are separated and discharged from the rear end of the evaporator, may be, for example, 1:9 to 10:0, specifically 2:8 to 8:2, and more specifically 3:7 to 6:4, but is not limited thereto. If the amount of waste heat recovery in the evaporator (200) is large, the mass flow rate ratio of the liquid stream supplied to the condenser (300) also increases. This means that as the amount of steam generated through waste heat recovery increases, the change in the stream fed into the condenser becomes large, and thus the risk of the operational stability of the condenser may further increase. However, if a condenser equipped with a partition (A) according to the present invention is introduced, such an operational stability problem can be solved.

[0064] In addition, referring to FIG. 1, by using a condenser (300) equipped with a partition wall (A), heat exchange between a first process fluid stream (11) and a second liquid process fluid stream (12) is performed inside the condenser (300), and then the condensed first process fluid stream and the cooled second process fluid stream are combined at the rear end of the condenser, and the combined process fluid stream (13) is supplied to a condenser drum (350) so that the liquid process fluid can be collected.

[0065] The internal temperature of the condenser drum (350) may vary depending on the characteristics of the process, and may be maintained at, for example, 20°C to 150°C, specifically 30°C to 100°C, and more specifically 40°C to 80°C, but is not limited thereto. Since the inside of the condenser drum is in a normal state, the temperature is the same at any location under the same operating conditions.

[0066] In addition, the inside of the condenser drum (350) can maintain a temperature difference of 5°C or less, specifically 3°C or less, and more specifically 2°C or less. Here, the temperature difference inside the condenser drum refers to the temperature difference inside the condenser drum that changes depending on whether steam is generated in the evaporator. By maintaining a small temperature difference in the condenser drum (350) within the above temperature range, the process can be operated under optimal operating conditions while maintaining process stability. Furthermore, if the internal temperature difference of the condenser drum increases, the reflux ratio of the process fluid may decrease, the separation and purification efficiency in the column and the purity of the product may deteriorate, and the change in the vapor mass fraction of the process fluid may affect the subsequent process.

[0067] Meanwhile, the lower discharge stream (14) of the condenser drum (350) may be refluxed to the column (100) or fed into a subsequent process such as a reaction process or a purification process, but is not limited thereto. Specifically, the liquid process fluid collected in the condenser drum (350) may be refluxed to the column (100) where the waste heat source is generated in order to reuse the process fluid. In addition, the upper discharge stream (15) of the condenser drum (350) may be fed into a subsequent process such as a reaction process or a purification process, or fed into the outside, but is not limited thereto.

[0068] The process fluid treatment system according to the present invention includes a plurality of heat exchangers (evaporators and condensers).

[0069] Specifically, a process fluid treatment system according to one embodiment of the present invention includes an evaporator (200) that generates steam by using a gaseous process fluid stream (10) supplied from a waste heat source as a heat source.

[0070] Boiler feedwater (BFW) flowing into the above evaporator (200) can be converted into steam (20) through heat exchange with the process fluid stream (10). Liquid boiler feedwater (BFW), for example, refrigerant having a temperature of 40°C to 150°C, specifically 60°C to 120°C, can be supplied and circulated to the above evaporator (200) under conditions of pressure of 1 to 20 bar, specifically 2 to 10 bar, and flow rate of 1 ton / hr to 10,000 ton / hr, specifically 10 ton / hr to 1,000 ton / hr. Meanwhile, the evaporator (200) can receive the process fluid stream (10) at a temperature range of, for example, 50°C to 250°C, specifically 40°C to 200°C, exchange heat with it, and then separate and discharge it into a first process fluid stream (11) in a gaseous state of 50°C to 200°C, specifically 50°C to 180°C, and a second process fluid stream (12) in a liquid state of 50°C to 200°C, specifically 50°C to 180°C. At this time, the temperatures of the first process fluid stream (11) in a gaseous state and the second process fluid stream (12) in a liquid state are the same.

[0071] A process fluid treatment system according to one embodiment of the present invention comprises: a first line connected to the upper portion of the rear end of the evaporator and transporting a first process fluid stream (11) in a gas phase discharged from the evaporator; a second line connected to the lower portion of the rear end of the evaporator and transporting a second process fluid stream (12) in a liquid phase discharged from the evaporator; and a condenser (300) connected to the first line and the second line and exchanging heat between the first process fluid stream (11) in a gas phase supplied from the evaporator and the second process fluid stream (12) in a liquid phase with a refrigerant (CW).

[0072] According to one embodiment of the present invention, as shown in FIG. 1, a partition wall (A) may be provided on the front head of the condenser (300) so that the interior may be separated into two regions. At this time, one region of the front head of the condenser is connected to the first line, so that the first process fluid stream (11) in a gaseous state supplied from the evaporator is condensed through heat exchange with the refrigerant (CW), and the other region of the front head of the condenser is connected to the second line, so that the second process fluid stream in a liquid state supplied from the evaporator may be cooled through heat exchange with the refrigerant (CW).

[0073] In addition, when vapor and liquid are separated in a two-phase stream, since the mass fraction of the liquid is about 70% or more but the volume fraction is less than about 5%, it may be preferable that the partition wall (A) be provided so that one region into which the vapor stream flows (i.e., the vapor region) has a larger volume than the other region into which the liquid stream flows (i.e., the liquid region). For example, the volume ratio of the vapor region and the liquid region may be 2:1 to 20:1, specifically 3:1 to 10:1, and more specifically 5:1 to 10:1.

[0074] A process fluid treatment system according to one embodiment of the present invention includes a condenser drum (350) connected to the condenser and collecting the heat-exchanged first process fluid stream and second process fluid stream (13).

[0075] The internal temperature of the condenser drum (350) may vary depending on the process, and may be maintained at, for example, 20°C to 150°C, specifically 30°C to 100°C, and more specifically 40°C to 80°C. In addition, the interior of the condenser drum (350) may maintain a temperature deviation of 5°C or less, specifically 3°C or less, and more specifically 2°C or less. By maintaining a small temperature deviation in the condenser drum (350) within the above temperature range, the process can be operated under optimal operating conditions while maintaining process stability.

[0076] In addition, the lower part of the condenser drum (350) is connected to the column (100) where the waste heat source is generated, so that the liquid process fluid collected in the condenser drum can be refluxed as a lower discharge stream (14).

[0077] According to one embodiment of the present invention, when necessary for waste heat fluid treatment, additional devices necessary for waste heat fluid treatment, such as valves, condensers, reboilers, pumps, separators, compressors, and mixers, may be additionally installed.

[0078] Above, the waste heat fluid treatment method according to the present invention has been described and illustrated in the drawings, but the description and illustration in the drawings describe and illustrate only the core components for understanding the present invention, and in addition to the processes and devices described and illustrated in the drawings, processes and devices not described and illustrated separately can be appropriately applied and utilized to implement the waste heat fluid treatment method according to the present invention.

[0079] Hereinafter, the present invention will be described in more detail through examples. However, the following examples are intended to further illustrate the present invention, and the scope of the present invention is not limited by the following examples.

[0080] [Example]

[0081] (1) Example 1

[0082] Example 1-1

[0083] As illustrated in Fig. 1, waste heat recovery and process fluid treatment were performed using a system in which a column (100), an evaporator (200), a condenser (300), and a condenser drum (350) were connected. Specifically, the front head of the condenser (300) was divided into one area and another area by a partition wall (A), such that the upper part of the rear end of the evaporator (200) was connected to one area of ​​the condenser (300), and the lower part of the rear end of the evaporator (200) was connected to another area of ​​the condenser (300).

[0084] First, a gaseous (110°C and 1.5 bar) process fluid stream (10) discharged from the top of the column (100) as a heat source was supplied to the evaporator (200) at a flow rate of 150 ton / hr, and also, boiler feed water (BFW) at 90°C was supplied under a pressure condition of 5 bar to exchange heat with the process fluid stream (10) to generate steam.

[0085] A portion (11) of the heat-exchanged process fluid stream was discharged in a vapor state at 102°C and 1.45 bar from the upper portion of the rear end of the evaporator (200) and supplied to a first tube of one region of the condenser (300), and the remainder (12) was discharged in a liquid state at 102°C and 1.45 bar from the lower portion of the rear end of the evaporator (200) and supplied to a second tube of another region of the condenser. At this time, the mass fraction of the gaseous process fluid stream (11) among the entire process fluid stream discharged from the evaporator was 0.2 (i.e., 20 wt% of the total 100 wt%), and the volume fraction was 0.99 (i.e., 99 vol% of the total 100 vol%).

[0086] Thereafter, refrigerant (32°C and 5 bar) was supplied to the shell of the condenser (300) at a flow rate of 500 ton / hr, and heat exchange was performed with the gaseous process fluid stream (11) supplied to the first tube and the liquid process fluid stream (12) supplied to the second tube, respectively. Accordingly, the gaseous process fluid stream was condensed, the liquid process fluid stream was cooled, and these were combined at the rear end of the condenser and discharged at 70°C.

[0087] Next, the 70°C process fluid stream (13) discharged from the condenser (300) was supplied to the condenser drum (350). At this time, the inside of the condenser drum (350) was 70°C and 1.3 bar, and the mass fraction of vapor among the entire process fluid collected inside the condenser drum (350) was 0.05 (i.e., 5 wt% of vapor among the total 100 wt%).

[0088] Thereafter, the gaseous process fluid collected inside the condenser drum (350) was discharged to the upper discharge stream (15) of the condenser drum and supplied as feed to the subsequent reaction process, and the liquid process fluid was discharged to the lower discharge stream (14) of the condenser drum and refluxed to the column (100).

[0089] Example 1-2

[0090] The same process as in Example 1-1 was performed, but boiler feed water (BFW) was not supplied to the evaporator (200), so that no steam was generated, and the process fluid was also discharged from the evaporator (200) in a 100 wt% vapor state (110°C and 1.5 bar) and supplied to the tubes of the condenser (300). In addition, refrigerant (32°C and 5 bar) was supplied to the shell of the condenser (300) at a flow rate of 1,750 ton / hr to perform heat exchange, and then a 70°C process fluid stream was supplied to the condenser drum (350). At this time, the inside of the condenser drum (350) was 70°C and 1.3 bar, and the mass fraction of the vapor among the entire process fluid collected inside the condenser drum (350) was 0.05 (i.e., 5 wt% of the total 100 wt% of the vapor).

[0091] Thereafter, the gaseous process fluid collected inside the condenser drum (350) was discharged to the upper discharge stream (15) of the condenser drum and supplied as feed to the subsequent reaction process, and the liquid process fluid was discharged to the lower discharge stream (14) of the condenser drum and refluxed to the column (100).

[0092] (2) Comparative Example 1

[0093] Comparative Example 1-1

[0094] As illustrated in Fig. 2, waste heat recovery and process fluid treatment were performed using a system in which a column (100), an evaporator (200), a condenser (300), and a condenser drum (350) were connected. Here, the condenser was a general condenser having the same heat exchange capacity as the condenser used in Example 1, but without a baffle at the front head.

[0095] First, a gaseous (110°C and 1.5 bar) process fluid stream (10) discharged from the top of the column (100) as a heat source was supplied to the evaporator (200) at a flow rate of 150 ton / hr, and also, boiler feed water (BFW) at 90°C was supplied under a pressure condition of 3 bar to exchange heat with the process fluid stream (10) to generate steam.

[0096] The heat-exchanged process fluid stream was discharged in a mixed vapor and liquid state (102°C and 1.45 bar; 11+12) without being separated by phase and was supplied entirely to the tubes of the condenser (300). At this time, the mass fraction of the gaseous process fluid stream among the entire process fluid stream discharged from the evaporator was 0.2 (i.e., 20 wt% of the total 100 wt%), and the volume fraction was 0.99 (i.e., 99 vol% of the total 100 vol%).

[0097] Thereafter, refrigerant (32°C and 5 bar) was supplied to the shell of the condenser (300) at a flow rate of 500 ton / hr, and heat exchange was performed with the two-phase process fluid stream (11+12) of vapor and liquid supplied to the tube. Accordingly, the process fluid stream was condensed and cooled and discharged at 70°C.

[0098] Next, the 70°C process fluid stream (13') discharged from the condenser (300) was supplied to the condenser drum (350). At this time, the inside of the condenser drum (350) was 70°C and 1.3 bar, and the mass fraction of vapor among the entire process fluid collected inside the condenser drum (350) was 0.05 (i.e., 5 wt% of vapor among the total 100 wt%).

[0099] Thereafter, the gaseous process fluid collected inside the condenser drum (350) was discharged to the upper discharge stream (15) of the condenser drum and supplied as feed to the subsequent reaction process, and the liquid process fluid was discharged to the lower discharge stream (14) of the condenser drum and refluxed to the column (100).

[0100] Comparative Example 1-2

[0101] The same process as in Comparative Example 1-1 was performed, but boiler feed water (BFW) was not supplied to the evaporator (200), so steam was not generated, and the process fluid was also discharged from the evaporator (200) in a 100 wt% vapor state (110°C and 1.5 bar) and supplied to the tubes of the condenser (300). In addition, after heat exchange was performed by supplying refrigerant (32°C and 5 bar) at a flow rate of 1,750 ton / hr to the condenser (300), a 70°C process fluid stream was supplied to the condenser drum (350). At this time, the inside of the condenser drum (350) was 70°C and 1.3 bar, and the mass fraction of the vapor among the entire process fluid collected inside the condenser drum (350) was 0.05 (i.e., 5 wt% of the total 100 wt% of the vapor).

[0102] Thereafter, the gaseous process fluid collected inside the condenser drum (350) was discharged to the upper discharge stream (15) of the condenser drum and supplied as feed to the subsequent reaction process, and the liquid process fluid was discharged to the lower discharge stream (14) of the condenser drum and refluxed to the column (100).

[0103] (3) Comparative Example 2

[0104] Comparative Example 2-1

[0105] As illustrated in Fig. 3, waste heat recovery and process fluid treatment were performed using a system in which a column (100), an evaporator (200), a condenser (300), and a condenser drum (350) were connected. Specifically, the upper rear end of the evaporator (200) was connected to a condenser (300), and the lower rear end of the evaporator (200) was connected to a condenser drum (350). Here, the condenser was a general condenser having the same heat exchange capacity as the condenser used in Example 1, but without a baffle on the front head.

[0106] First, a gaseous (110°C and 1.5 bar) process fluid stream (10) discharged from the top of the column (100) as a heat source was supplied to the evaporator (200) at a flow rate of 150 ton / hr, and also, boiler feed water (BFW) at 90°C was supplied under a pressure condition of 3 bar to exchange heat with the process fluid stream (10) to generate steam.

[0107] A portion (11) of the heat-exchanged process fluid stream was discharged from the upper portion of the rear end of the evaporator (200) in a vapor state at 102°C and 1.45 bar and supplied to the tube of the condenser (300), and the remainder (12) was discharged from the lower portion of the rear end of the evaporator (200) in a liquid state at 102°C and 1.45 bar and supplied to the condenser drum (350). At this time, the mass fraction of the gaseous process fluid stream (11) among the entire process fluid stream discharged from the evaporator was 0.2 (i.e., 20 wt% of the total 100 wt%), and the volume fraction was 0.99 (i.e., 99 vol% of the total 100 vol%).

[0108] Thereafter, refrigerant (32°C and 5 bar) was supplied to the shell of the condenser (300) at a flow rate of 420 ton / hr, and heat exchange was performed with the gaseous process fluid stream (11) supplied to the tube. Accordingly, the process fluid stream was condensed and cooled and discharged at 70°C.

[0109] Next, the 70°C process fluid stream (11') discharged from the condenser (300) was supplied to the condenser drum (350). At this time, the inside of the condenser drum (350) was 76°C and 1.3 bar, and the mass fraction of vapor among the entire process fluid collected inside the condenser drum (350) was 0.13 (i.e., 13 wt% of vapor among the total 100 wt%).

[0110] Thereafter, the gaseous process fluid collected inside the condenser drum (350) was discharged to the upper discharge stream (15) of the condenser drum and supplied as feed to the subsequent reaction process, and the liquid process fluid was discharged to the lower discharge stream (14) of the condenser drum and refluxed to the column (100).

[0111] Comparative Example 2-2

[0112] The same process as in Comparative Example 2-1 was performed, but boiler feed water (BFW) was not supplied to the evaporator (200), so steam was not generated, and the process fluid was also discharged from the evaporator (200) in a 100 wt% vapor state (110°C and 1.5 bar) and supplied to the tubes of the condenser (300). In addition, after heat exchange was performed by supplying refrigerant (32°C and 5 bar) at a flow rate of 1,750 ton / hr to the condenser (300), a 70°C process fluid stream was supplied to the condenser drum (350). At this time, the inside of the condenser drum (350) was 70°C and 1.3 bar, and the mass fraction of the vapor among the entire process fluid collected inside the condenser drum (350) was 0.05 (i.e., 5 wt% of the total 100 wt% of the vapor).

[0113] Thereafter, the gaseous process fluid collected inside the condenser drum (350) was discharged to the upper discharge stream (15) of the condenser drum and supplied as feed to the subsequent reaction process, and the liquid process fluid was discharged to the lower discharge stream (14) of the condenser drum and refluxed to the column (100).

[0114] (4) Experimental example

[0115] Table 1 below shows the phase of the process fluid stream discharged from the evaporator (200), the amount of heat used in the condenser (300), the operating stability of the condenser (300), the temperature (℃) inside the condenser drum (350), the vapor mass fraction, and whether the temperature was controlled, depending on whether steam was generated in Example 1, Comparative Examples 1 and 2.

[0116] Specifically, the heat utilization rate of the condenser (300) was compared with the heat utilization rate of the condenser for the gaseous process fluid stream as 100% when steam was not generated, i.e., when boiler feedwater was not supplied to the evaporator, as in Example 1-2 and Comparative Examples 1-2 and 2-2. For example, in Table 1 below, a condenser heat utilization rate of 30% means that 70% of the heat was used in the evaporator and 30% of the heat was used in the condenser.

[0117] In addition, the operating stability of the condenser is determined by the “ρv” of the process fluid flowing into the condenser (300) depending on whether steam is generated in each of the examples and comparative examples. 2 ” (ρ = density of process fluid, v = velocity of process fluid) was calculated and judged. Specifically, “ρv”, which is one of the variables that generally judges the stability of a heat exchanger 2 ” value depends on the design of the heat exchanger, “ρv 2 The maximum allowable value of ρv is determined based on the fluid properties and operating conditions supplied to the condenser in each process. 2 The value can be calculated. Therefore, ρv of the condenser 2 Based on the maximum allowable value, the maximum ρv calculated in each process 2 If the value is within the above maximum allowable value, the operating stability is judged to be excellent and “O” is recorded. If the value exceeds the above maximum allowable value, the operating stability of the condenser is judged to be poor and “X” is recorded.

[0118] Furthermore, whether the temperature of the condenser drum was controlled was determined to be successful if the temperature deviation inside the condenser drum was 5℃ or less depending on whether steam was generated, and “O” was recorded. If the temperature deviation inside the condenser drum was more than 5℃, the temperature control was determined to be unsuccessful, and “X” was recorded.

[0119] Device Type Item Example 1 (Fig. 1) Comparative Example 1 (Fig. 2) Comparative Example 2 (Fig. 3) 1-11-21-11-22-12-2 Evaporator (200) Steam generation OXOXOX Discharge process fluid stream above / liquid device / liquid device / liquid device Condenser (300) Heat utilization rate 30% 100% 30% 100% 30% 100% Maximum ρv 2 2492,95250,8372,9522352,952ρv 2 Maximum allowable standard 5,9535,9535,9535,9535,9535,953 Operational stability OOXOOO Condenser drum (350) Internal temperature 70℃70℃70℃70℃76℃70℃ Vapor mass fraction 0.050.050.050.050.130.05 Temperature control OOOOXO

[0120] As can be seen in Table 1 above, when processing a process fluid with the method and system according to the present invention, not only can the operating stability of the condenser (300) be ensured regardless of whether steam is generated in the evaporator (200), but also the internal temperature in the condenser drum (350) can be controlled, so that the mass fraction of the steam can also be controlled.

[0121] On the other hand, as in Comparative Example 1, when the two-phase process fluid stream generated in the evaporator (200) was processed into the condenser at once without being separated, a problem occurred in the operating stability of the condenser.

[0122] In addition, as in Comparative Example 2, even if the two-phase process fluid stream generated in the evaporator (200) is separately discharged, if only the gaseous process fluid stream (11) is condensed, the internal temperature of the condenser drum (350) cannot be controlled, so the mass fraction of the vapor increases. Through this, it was confirmed that if the internal temperature of the condenser drum (350) is not controlled, the upper discharge stream (15) of the condenser drum cannot be supplied consistently to the subsequent process, so the stability of the subsequent process is deteriorated.

[0123] Although exemplary embodiments of the present invention have been described above, the present invention is not limited thereto, and those skilled in the art will understand that various changes and modifications are possible within the scope and spirit of the claims set forth below.

[0124] [Explanation of symbols]

[0125] 100: Column

[0126] 200: Evaporator

[0127] 250: Pressurization system

[0128] 300: Condenser

[0129] 350: Condenser drum

[0130] 10, 11, 11', 12, 13, 13' 14, 15: Process fluid

[0131] 20: Steam

[0132] BFW: Boiler feedwater

[0133] CW: Refrigerant

Claims

1. A step of supplying a gaseous process fluid stream from a waste heat source to an evaporator, converting it into a two-phase process fluid through heat exchange, and separately discharging it as a first gaseous process fluid stream and a second liquid process fluid stream from the rear end of the evaporator; A step of supplying the first process fluid stream in the gas phase to one region of a condenser having a front-end head and having the interior divided into two regions, and supplying the second process fluid stream in the liquid phase to the other region; and A process fluid treatment method, comprising the step of condensing the first process fluid stream in the gas phase and cooling the second process fluid stream in the liquid phase through heat exchange in the condenser.

2. In paragraph 1, A method of treating waste heat fluid, comprising recovering waste heat by supplying water to the evaporator to generate steam through heat exchange with the process fluid stream of the gas phase.

3. In paragraph 1, A process fluid treatment method, wherein the initial temperature of the process fluid stream flowing into the above evaporator is 50°C to 250°C.

4. In paragraph 1, A process fluid treatment method comprising supplying the first process fluid stream and the second process fluid stream condensed in the condenser to a condenser drum to collect the process fluid.

5. In paragraph 4, A process fluid treatment method wherein the internal temperature of the condenser drum is maintained at a temperature difference of 5℃ or less.

6. In paragraph 4, A process fluid treatment method comprising refluxing the process fluid collected in the condenser drum to the waste heat source.

7. In paragraph 1, A process fluid treatment method, wherein the volume ratio of one region to which the first process fluid stream of the above-mentioned gas phase is supplied and another region to which the second process fluid stream of the above-mentioned liquid phase is supplied is 2:1 to 20:

1.

8. An evaporator that generates steam using a gaseous process fluid stream supplied from a waste heat source as a heat source; A first line connected to the upper portion of the rear end of the evaporator and transporting a first process fluid stream of gaseous phase discharged from the evaporator; A second line connected to the lower portion of the rear end of the evaporator and transporting a second process fluid stream in liquid form discharged from the evaporator; A condenser connected to the first line and the second line, which exchanges heat between the first process fluid stream in the gas phase and the second process fluid stream in the liquid phase supplied from the evaporator and the refrigerant; and A condenser drum connected to the condenser and collecting the heat-exchanged first process fluid stream and the second process fluid stream; A baffle is provided on the front head of the above condenser, dividing the interior into two areas. A region of the front head of the above condenser is connected to the first line, so that a first process fluid stream of gaseous phase supplied from the evaporator is condensed through heat exchange, A process fluid treatment system, wherein the other area of ​​the front head of the condenser is connected to the second line, and a second process fluid stream in liquid form supplied from the evaporator is cooled through heat exchange.

9. In paragraph 8, A process fluid treatment system wherein a boiler feedwater stream is introduced into the evaporator and heat-exchanged with the process fluid stream to generate steam.

10. In paragraph 8, A process fluid treatment system in which the internal temperature of the above condenser drum is maintained with a temperature difference of 5℃ or less.

11. In paragraph 8, A process fluid treatment system, wherein the lower portion of the condenser drum is connected to the waste heat source, and the liquid process fluid collected in the condenser drum is refluxed.

12. In paragraph 8, A process fluid treatment system, wherein the volume ratio of one area of ​​the front head of the condenser to another area is 2:1 to 20:1.

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