Cold box system arranged in height direction

Abstract

The utility model discloses a cold box system arranged in the height direction, the cold box system is provided with a heat exchanger and a turbo-expander which are arranged from high to low in the vertical direction, a bottom outlet of the heat exchanger is communicated to a top inlet of the turbo-expander through a connecting component, a liquid accumulation basin is used for separating the connecting component from the heat exchanger, and the liquid accumulation basin is communicated with the turbo-expander. The container is used for containing leaked liquid of the cold box system. The lower space of the heat exchanger cold box is fully utilized, so that more occupied area is saved, and the installation cost is saved.

Description

Technical Field

[0001] The present application belongs to the field of air separation, and relates to a layout of a cold box, and in particular to a cold box system arranged in a height direction. Background Art

[0002] Many components of air separation equipment work under low temperature conditions below -50°C or even below -100°C. In order to be thermally isolated from the atmosphere, these components, such as (multiple) distillation columns, (multiple) heat exchangers, (multiple) condenser evaporators, (multiple) phase separators, (multiple) cryogenic pumps / (multiple) expanders and (multiple) interconnecting pipelines, need to be housed in one or more cold boxes. The cold box is an insulating shell that completely surrounds the insulated inner cavity through an outer wall, and the space between the outer wall and the contained components is usually filled with insulating materials such as perlite.

[0003] As disclosed in the Chinese invention patent with publication number CN110662935A, a typical gas production system supplies liquefied gas obtained by rectifying a gas source as a product gas. A first heat exchanger, a turbo expansion, a recycle gas source compressor, a high-pressure rectification column, a low-pressure rectification column, and a pressure device are sequentially arranged from left to right in a cold box. In the first heat exchanger, the compressor, and the high-pressure rectification column, a recycle gas pipeline is formed, and the air flow is recirculated.

[0004] In the usual design, the heat exchanger is close to the tower, which increases the size of the cold box and causes problems related to transportation restrictions or difficulties. In some working conditions, the heat exchanger is required to be set at a higher vertical height to have a sufficient drop in height in order to reduce the use of pumps. If the cold box setting in the prior art is adopted, it will take up more space. Utility Model Content

[0005] In order to make full use of the space below the heat exchanger and reduce the floor space of the cold box area, the present application designs a cold box system arranged along the height direction.

[0006] The purpose of this application is to optimize the arrangement of various components including cold boxes and pipelines in an air separation device, and to integrate the pipelines (pipelines) of a turbo expander into the outer shell at the bottom of the cold box to save construction costs and time, save on-site area, and improve reliability.

[0007] In particular, the present application focuses on the configuration of the cold box. By arranging the heat exchanger above the turbo expander and arranging them in sequence in the vertical space, the floor space is further reduced. The valves of the heat exchanger and various pipelines (pipelines) are arranged at different heights.

[0008] In order to achieve the above-mentioned objectives, the present application discloses a cold box system arranged in the height direction, which is equipped with a heat exchanger and a turbo expander arranged from high to low in the vertical direction, and the bottom outlet of the heat exchanger is connected to the top inlet of the turbo expander through a connecting member, wherein a liquid accumulation basin separates the connecting member and the heat exchanger to accommodate leaked liquid of the cold box system.

[0009] Furthermore, the cold box is a closed square box body formed by welding a steel structure frame and cold box panels on all sides.

[0010] Furthermore, the connecting member is an L-shaped sleeve.

[0011] Furthermore, a temperature detector is installed in the liquid accumulation basin to detect leaked liquid.

[0012] Furthermore, all pipelines passing through the liquid accumulation basin are sealed and welded.

[0013] Furthermore, a filling pipeline is respectively arranged at the top of both sides of the liquid accumulation basin.

[0014] Further, the height of the filling pipeline is greater than the height of the liquid accumulation basin.

[0015] Furthermore, the filling pipeline is a perlite filling pipeline.

[0016] Furthermore, a purge line is provided at the bottom of the heat exchanger.

[0017] Further, the cold box system also includes a stair module, which can be attached to the cold box system on site.

[0018] Further, when the cold box system is shipped in two sections, the method for installing the cold box may include installing the bottom cold box section in a vertical orientation and then lifting the top cold box section and placing the top cold box section on top of the bottom cold box section.

[0019] Compared with the prior art, the technical solution provided by this application has the following advantages:

[0020] By making full use of the lower space of the heat exchanger cold box, more floor space can be saved and installation costs can be saved. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The advantages and spirit of the present application can be further understood through the following detailed description and accompanying drawings.

[0022] Figure 1 It is a schematic diagram of the cold box system arranged along the height direction provided in this application.

[0023] In the figure: 101-heat exchanger; 102-liquid accumulation basin; 103-L-type casing, 104-turbo expander. DETAILED DESCRIPTION

[0024] The specific embodiments of the present application are described in detail below in conjunction with the accompanying drawings. However, the present application should be understood as not being limited to the implementation described below, and the technical concept of the present application can be implemented in combination with other known technologies or other technologies with the same functions as those known technologies.

[0025] In the description of the following specific embodiments, in order to clearly demonstrate the structure and working method of the present application, many directional words will be used for description, but words such as "front", "rear", "left", "right", "outside", "inside", "outward", "inward", "axial", and "radial" should be understood as convenient terms and should not be understood as restrictive terms.

[0026] In the description of the following specific embodiments, it should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and are therefore not to be construed as a limitation on the present application.

[0027] A component or device is "below" another component or device when its top edge is located at a lower geodesic level than the bottom edge of the other component.

[0028] In addition, the terms "first" and "second" are only used for descriptive purposes, and do not refer to the limitation of time sequence, quantity, or importance. They cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features, but are only for distinguishing one technical feature from another technical feature in the technical solution. Thus, the features defined as "first" and "second" can explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically specified. Similarly, the qualifiers similar to "one" appearing in this article do not refer to the limitation of quantity, but describe technical features that have not appeared in the previous text. Similarly, unless it is a noun modified by a specific quantitative quantifier, it should be regarded as including both singular and plural forms in this article, and the technical solution can include both singular and plural technical features. Similarly, modifiers similar to "approximately" and "approximately" appearing before the numerals in this article usually include the number itself, and their specific meanings should be understood in conjunction with the context.

[0029] It should be understood that in the present application, "at least one (item)" means one or more, and "plurality" means two or more. "And / or" is used to describe the association relationship of associated objects, indicating that three relationships may exist. For example, "A and / or B" can mean: only A exists, only B exists, and A and B exist at the same time, where A and B can be singular or plural. The character " / " generally indicates that the objects associated before and after are in an "or" relationship. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b or c can mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, c can be single or multiple.

[0030] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be fixedly connected, detachably connected, or integrated; it can be mechanically connected or electrically connected; it can be directly connected, or indirectly connected through an intermediate medium, it can be the internal communication of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances. "Fixedly connected" or "fixedly connected" or "non-movably connected" is understood to mean that the connection between two or more structural members is not constructed to provide relative movement. An example of a fixed connection is a welded connection or a bolted connection, and in some cases a weld and a bolted connection. "Moveably connected" or "movable" or "movable connection" is understood to mean a connection between two or more structural members that allows horizontal and / or vertical relative movement between the members under extreme dynamic loads. Such a connection generally does not allow movement under static loads or general dynamic loads (for example, as applied by light / moderate wind).

[0031] The terms “unit”, “item”, “thing”, and “module” described in the present specification mean a unit for processing at least one function and operation, and may be implemented by a hardware component or a software component and a combination thereof.

[0032] The term "sealed connection" or "sealable connection" denotes the following feature: two component containers are connected or connectable by welding, adhesive bonding, threading or other means, so that when pressure is built up to empty the multi-chamber mixing container, no contents can leak out of the multi-chamber mixing container through the sealed connection.

[0033] In the terms used herein, a "heat exchanger" is a device designed to indirectly transfer heat between at least two fluid flows, for example, directed to countercurrent relative to each other. The heat exchanger used within the scope of the present application can be formed by parts of one or more heat exchangers connected in parallel and / or in series, for example, by one or more plate heat exchanger blocks. However, the present application is also applicable to other types of heat exchangers in principle and is not limited to plate heat exchangers. The heat exchanger has "channels" that are configured to conduct fluids and are separated from other channels by separation plates or connected only on the inlet and outlet sides via corresponding headers. The channels are separated from the outside by side strips. The channels are referred to as "heat exchanger channels" hereinafter. According to conventional terminology, the terms "heat exchanger", "heat transfer device", and "heat exchange device" are used synonymously hereinafter. This also applies to the terms "heat exchange" and "heat transfer". In a typical air separation unit, the main heat exchanger is used to cool multiple feed air flows by indirect heat exchange with the return flow from the separation tower. In its construction, the side where the higher temperature stream, such as the feed air stream, is fed is called the hot end; the side where the lower temperature stream, such as the return stream from the separation column, is fed is called the cold end. Usually, the hot end and the cold end are located oppositely on the main heat exchanger. For example, the heat exchanger is installed vertically, with the hot end facing up and the cold end facing down.

[0034] The equipment used to deliver / introduce these flows includes the necessary piping, pressure relief or expansion devices, and connection ports.

[0035] As used herein, a "cold box" is understood to be an insulating housing which completely encloses an insulating interior in an outer wall; in the interior the plant components to be insulated are arranged, for example one or more separation towers and / or heat exchangers. The insulation effect can be achieved by a suitable design of the outer wall and / or by filling the gaps between the plant components and the outer wall with insulating material. The latter preferably uses a powdered material, for example perlite. Not only the towers and heat exchangers are enclosed in the cold box, but also other cold plant components are enclosed by one or more cold boxes, which at the same time makes the volume of the cold box quite large.

[0036] In the case of prefabricated installations, the external dimensions of the cold box determine the transport dimensions of the package. The "height" of the cold box is understood to mean the dimension in the vertical direction based on the orientation of the cold box during operation of the installation; the "cross section" is the area perpendicular to it (horizontally). The longitudinal axis of the cold box and the tower is the axis parallel to the height. In transportation, the cold box is shipped in a horizontal manner, therefore, the height of the cold box determines the length in transportation, while the cross section determines the height and width in transportation.

[0037] Unless clearly indicated to the contrary, each aspect or embodiment defined herein may be combined with any other aspect or embodiments. In particular, any feature indicated as preferred or advantageous may be combined with any other feature indicated as preferred or advantageous.

[0038] The specific embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0039] Example 1

[0040] A typical cryogenic refrigeration device is arranged in a cold box and comprises a working circuit, which forms a loop and is filled with a working fluid, and the working circuit forms a cycle, which comprises in series: a component for compressing the working fluid, a component for cooling the working fluid, a component for expanding the working fluid, and a component for heating the working fluid.

[0041] The cryogenic refrigeration device comprises a heat exchanger intended to extract heat at at least one component by exchanging heat with the working fluid circulating in the working circuit, while the component for expanding the working fluid comprises at least one turboexpander.

[0042] When the cryogenic refrigeration unit is in operation, the temperature of the heat exchanger is equalized along the longitudinal gradient between the cold end and the hot end. The inlet of the turboexpander receives the working fluid from the heat exchanger.

[0043] Exemplarily, the heat exchanger cold box is a closed square box formed by welding a steel structure frame and cold box plates on all sides, with an aluminum plate heat exchanger and the expansion end of a turbo expander built in, and the interior is filled with pearlescent sand and other insulation materials.

[0044] The components are connected by pipes (pipelines). The pipes connected to the cold box are low-temperature pipes, and it is necessary to consider the cold insulation measures of the pipes. The pipes in the cold box are in a low-temperature state. In addition to considering the low-temperature resistance of the pipes, it is also necessary to consider the stress of the low-temperature pipes.

[0045] Figure 1 A schematic diagram of the cold box area in this embodiment is shown.

[0046] In the vertical direction, the heat exchanger 101 is arranged at a high position, and the turbo expander 104 is arranged at a low position. A vertical L-shaped casing 103 connects the heat exchanger 101 and the turbo expander 104 .

[0047] For example, liquid leaking within a cold box near the top may contact the insulation (thermal insulation) material (e.g., perlite), causing the perlite to freeze, which reduces the contraction and expansion of these pipes penetrating the top and / or potentially increases the weight of these pipes and pipes or instrumentation pipes near or below the ice layer. Embodiments of the present application reduce and / or eliminate these problems.

[0048] A liquid accumulation basin 102 for accommodating possible leaked liquid separates the L-shaped sleeve 103 and the heat exchanger 101. All pipelines passing through the liquid accumulation basin 102 are required to be sealed and welded. This effectively avoids the risk of liquid leakage from the heat exchanger damaging surrounding equipment.

[0049] The liquid accumulation basin 102 is used as a leakage discharge detection device to detect whether there is liquid (cold liquid) leakage. For example, a temperature detector can be used to detect cold liquid leakage. When the ultra-low temperature liquid in the cold box leaks, the leaked cold liquid flows downward into the liquid accumulation basin 102. The temperature detector can detect the temperature change at the bottom of the liquid accumulation basin 102 in a timely manner, so as to quickly detect the leakage and reduce the risk of the cold box collapsing due to the cold liquid and brittle steel structure. At the same time, the leakage signal can be transmitted to the corresponding controller to trigger an alarm.

[0050] When partially connected to the heat exchanger 101, due to the presence of the liquid accumulation basin 102, all pipelines passing through the liquid accumulation basin 102 are sealed and welded. At this time, the top of the pipeline passing through the liquid accumulation basin 102 needs to be separated from the top cold box, and it is difficult to fill the insulation material such as perlite from the top of the heat exchanger cold box according to the conventional operation in the field. In order to solve the perlite filling problem, a dedicated perlite filling pipeline is added in this embodiment.

[0051] For example, perlite filling pipelines can be provided at the top of both sides of the liquid accumulation basin 102, and corresponding openings can be provided on the liquid accumulation basin 102 according to the size of the perlite filling pipelines. The perlite filling pipelines are welded to these openings and pass through the heat exchanger 101, and flanges and blind plates are provided at the ends thereof. In addition, for safety reasons, a purge pipeline is provided at the bottom of the heat exchanger 101, and the purge pipeline can be used for perlite filling during the construction stage. Purging after filling can also ensure that the perlite can pass through the L-shaped casing 103 densely and evenly.

[0052] Preferably, the perlite filling pipelines are stainless steel pipelines, and their height is higher than the height of the sump basin 102 .

[0053] The stainless steel pipeline is sealed and welded to the opening on the effluent basin 102. This design allows the perlite to pass through and continue to fill the lower low-position pipeline while avoiding the risk of cryogenic liquid leaking from the opening to the lower pipeline.

[0054] The two stainless steel pipelines are vertically arranged and can be externally mounted on one side of the cold box system so that operators can fill perlite in large quantities and save time. Alternatively, they can be built inside the cold box so that perlite can be moved more easily from the top to the bottom. The perlite filling pipeline can make the physically isolated cold box at the bottom densely and evenly filled with perlite, thereby ensuring good insulation of the lower parts.

[0055] In this embodiment, the cold box system may further include a stair module, which may be attached to the cold box system on site.

[0056] In this embodiment, the method for installing the cold box when it is shipped in two sections may include installing the bottom cold box section in a vertical orientation, then lifting the top cold box section and placing the top cold box section on top of the bottom cold box section. In one embodiment, instead of welding the two sections together, the two sections may be bolted together. Bolting the two cold box sections together instead of welding greatly reduces on-site time and necessary equipment.

[0057] In this embodiment, the cold box system may include pre-installed platforms that are positioned to be operable to allow a user to access the pre-assembled pipes. In the case of two cold boxes placed side by side, this advantageously provides access and workspace for workers to connect pipes from one cold box to another without the expense and time of constructing temporary scaffolding as is traditionally done.

[0058] In this embodiment, it is also possible to bolt the top cold box assembly to the bottom cold box assembly at the installation site while still in the horizontal position, and then raise the entire cold box assembly in one piece to the vertical position.

[0059] The present specification only describes the preferred specific embodiments of the present application, and the above embodiments are only used to illustrate the technical solutions of the present application rather than to limit the present application. Any technical solutions that can be obtained by those skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present application should be within the scope of the present application.

Claims

1. A cold box system arranged in the height direction, characterized in that: The cold box system is configured with a heat exchanger and a turbo expander arranged vertically from high to low, wherein the bottom outlet of the heat exchanger is connected to the top inlet of the turbo expander via a connecting member, wherein a liquid accumulation basin separates the connecting member and the heat exchanger for accommodating leaked liquid of the cold box system.

2. The cold box system according to claim 1, characterized in that: The cold box system is a closed square box formed by welding a steel structure frame and cold box panels on all sides.

3. The cold box system according to claim 1, characterized in that: The connecting member is an L-shaped sleeve.

4. The cold box system according to claim 1, characterized in that: A temperature detector is installed in the liquid accumulation basin to detect leaked liquid.

5. The cold box system according to claim 1, characterized in that: All pipelines passing through the liquid accumulation basin are sealed and welded.

6. The cold box system according to claim 1, characterized in that: A filling pipeline is respectively arranged on the top of both sides of the liquid accumulation basin.

7. The cold box system according to claim 6, characterized in that: The height of the filling line is greater than the height of the sump basin.

8. The cold box system according to claim 6, characterized in that: The filling pipeline is a perlite filling pipeline.

9. The cold box system according to claim 1, characterized in that: A purge line is provided at the bottom of the heat exchanger.

10. The cold box system according to claim 1, characterized in that: The cold box system also includes a stair module that can be attached to the cold box system in the field.

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