Gas cooling system

Abstract

A gas cooling system is used for cooling process gas in a polyethylene reactor and is characterized in that the gas cooling system comprises two coolers arranged in parallel, and each cooler comprises a cooler body, a cooler inlet pipeline connected to the inlet end of the cooler body and a cooler outlet pipeline connected to the outlet end of the cooler body; the air inlet pipeline is connected to the cooler inlet pipeline from the outlet side of the polyethylene reactor through a recycle gas compressor; the air inlet switching device is arranged between the air inlet pipeline and the coolers and is configured to selectively connect the air inlet pipeline to the cooler inlet pipeline of one of the coolers; the air outlet pipeline is connected to the cooler outlet pipeline from the inlet side of the polyethylene reactor; and the air outlet switching device is arranged between the air outlet pipeline and the coolers and is configured to selectively connect the air outlet pipeline to the cooler outlet pipeline of one cooler.

Description

Technical Field

[0001] The present application relates to the field of chemical engineering, and in particular to a gas cooling system in a polyethylene (PE) production process. Specifically, the present application relates to a gas cooling system for cooling process gas in a polyethylene reactor. Background Art

[0002] Polyethylene (PE) production is typically carried out in a reactor via olefin polymerization. This highly exothermic polymerization process requires continuous and effective removal of the generated heat to maintain a stable temperature within the reactor, ensuring safe and stable reaction progress and producing a qualified product. In many PE production processes, the circulating process gas within the reactor serves as the primary heat transfer medium. As it absorbs the heat of reaction, its temperature rises, requiring cooling via an external cooler.

[0003] However, since the process gas usually contains polyethylene powder, this powder will gradually accumulate in the pipe process of the cooler, resulting in a decrease in heat exchange efficiency. Therefore, the cooler needs to be cleaned (such as high-pressure water cleaning) or maintained regularly. The traditional solution is to set up an offline spare cooler, and when the online cooler needs maintenance, production is stopped and replaced with the spare cooler. This method has significant disadvantages, including: the replacement process requires a long downtime, resulting in production losses; maintenance work (such as hoisting and pipe connection / disassembly of large equipment) is complicated and labor-intensive; and the related safety risks are high. Therefore, it is difficult for the existing technology to quickly and conveniently maintain the polyethylene circulating gas cooler while ensuring process requirements and safety. There is an urgent need for a technical solution that can solve the above problems. Utility Model Content

[0004] To solve the above technical problems, the present application proposes a gas cooling system. According to the gas cooling system of the present application, the cooler can be replaced in a relatively short time, which greatly shortens the maintenance time of the cooler, reduces the downtime of the polyethylene reactor, and improves the production efficiency of polyethylene.

[0005] The present application discloses a gas cooling system for cooling process gas in a polyethylene reactor, characterized in that the gas cooling system comprises: two coolers arranged in parallel, the cooler comprising a cooler body, a cooler inlet pipe connected to the inlet end of the cooler body, and a cooler outlet pipe connected to the outlet end of the cooler body; an air inlet pipe, which is connected to the cooler inlet pipe from the outlet side of the polyethylene reactor via a circulating gas compressor; an air inlet switching device, which is arranged between the air inlet pipe and the cooler and is configured to selectively connect the air inlet pipe to the cooler inlet pipe of one of the coolers; an air outlet pipe, which is connected to the cooler outlet pipe from the inlet side of the cooled polyethylene reactor; and an air outlet switching device, which is arranged between the air outlet pipe and the cooler and is configured to selectively connect the air outlet pipe to the cooler outlet pipe of one of the coolers.

[0006] According to an optional embodiment, the air intake switching device and the air outlet switching device are configured to connect the air intake duct and the air outlet duct to the same cooler.

[0007] According to an optional embodiment, the cooler inlet pipe includes a cooler inlet elbow pipe section and a cooler inlet flange arranged at the end of the cooler inlet elbow pipe section; and the cooler outlet pipe includes a cooler outlet elbow pipe section and a cooler outlet flange arranged at the end of the cooler outlet elbow pipe section.

[0008] According to an optional embodiment, the air inlet duct is provided with an air inlet duct flange at the end thereof; and the air outlet duct is provided with an air outlet duct flange at the end thereof.

[0009] According to an optional embodiment, the air intake switching device includes an air intake elbow pipe section, an air intake elbow pipe section fastener, and air intake elbow pipe flanges provided at both ends of the air intake elbow pipe section;

[0010] One end of the air intake elbow pipe section is rotatably connected to the air intake pipe through the air intake elbow pipe flange and the air intake pipe flange; the other end of the air intake elbow pipe section is selectively connected to one of the coolers through the air intake elbow pipe flange and the cooler inlet flange; and the air intake elbow pipe section fastener operably fixes the air intake elbow pipe flange and the air intake pipe flange at one end of the air intake elbow pipe section together, and operably fixes the air intake elbow pipe flange and the cooler inlet flange at the other end of the air intake elbow pipe section together.

[0011] According to an optional embodiment, the air outlet switching device includes an air outlet elbow pipe section, an air outlet elbow pipe section fastener and an air outlet elbow pipe flange arranged at both ends of the air outlet elbow pipe section; one end of the air outlet elbow pipe section is rotatably connected to the air outlet pipe through the air outlet elbow pipe flange and the air outlet pipe flange; the other end of the air outlet elbow pipe section is selectively connected to one of the coolers through the air outlet elbow pipe flange and the cooler outlet flange; and the air outlet elbow pipe section fastener operably fixes the air outlet elbow pipe flange and the air outlet pipe flange at one end of the air outlet elbow pipe section, and operably fixes the air outlet elbow pipe flange and the cooler outlet flange at the other end of the air outlet elbow pipe section together.

[0012] According to an optional embodiment, a shut-off valve is provided in the air inlet pipe to selectively cut off the gas flow in the air inlet pipe; and a flow valve is provided in the air outlet pipe to steplessly change the gas flow in the air outlet pipe.

[0013] According to an optional embodiment, the gas cooling system includes a controller; and the controller is connected to the shut-off valve and the flow valve to control the switching state of the shut-off valve and the opening degree of the flow valve.

[0014] According to an optional embodiment, the gas cooling system includes a cooling water pipeline; and the cooling water pipeline is connected to the cooler.

[0015] According to an optional embodiment, the gas cooling system includes an overflow valve and a drain pipe; the overflow valve is provided on the cooler; and the drain pipe is connected to the overflow valve to drain the cooling water in the cooler.

[0016] The gas cooling system according to the present application allows one cooler to be online while another standby cooler is offline. When needed, process gas can be switched to the standby cooler via a quick-connect assembly, allowing maintenance (such as high-pressure water cleaning) on ​​the original online cooler without requiring a long production stoppage. The gas cooling system according to the present application avoids the complex and high-risk heavy lifting and mechanical connection work required in traditional systems, thereby improving operational safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Hereinafter, embodiments of the present invention will be described in more detail with reference to the accompanying drawings, in which:

[0018] Figure 1 is a schematic diagram of a gas cooling system according to the present application.

[0019] Figure 2 yes Figure 1 A partial perspective view of the gas cooling system.

[0020] According to the detailed description carried out below in conjunction with the accompanying drawings, other purposes and features of the embodiments of this invention will become apparent. However, it should be understood that the accompanying drawings are designed for illustration purposes only and are not intended to limit the scope of this application. DETAILED DESCRIPTION

[0021] The following describes exemplary embodiments of the present application in more detail with reference to the accompanying drawings. Although the accompanying drawings illustrate exemplary embodiments of the present application, it should be understood that the present application can be implemented in various forms and is not limited by the embodiments shown in the accompanying drawings. Rather, these embodiments are provided to enable a more thorough understanding of the present application and to fully convey the scope of the present application to those skilled in the art.

[0022] Figure 1 is a schematic diagram of a gas cooling system 100 according to the present application. It should be understood that Figure 1 The diagram only schematically illustrates the connection relationship between the components, and does not illustrate the actual size, shape or position of the components. Figure 1 As shown, the gas cooling system 100 is used to cool the process gas in the polyethylene reactor 1. The gas cooling system 100 includes two coolers 110 arranged in parallel. The cooler 110 includes a cooler body 111, a cooler inlet pipe 112 connected to the inlet end of the cooler body 111, and a cooler outlet pipe 113 connected to the outlet end of the cooler body 111.

[0023] The gas cooling system 100 further includes an inlet pipe 120, an inlet switching device 130, an outlet pipe 140, and an outlet switching device 150. The inlet pipe 120 is connected to the cooler 110 from the outlet side 2 of the polyethylene reactor 1 via a circulating gas compressor (not shown) and via the inlet switching device 130. The inlet switching device 130 is disposed between the inlet pipe 120 and the cooler 110 and is configured to selectively connect the inlet pipe 120 to the cooler inlet pipe 112 of one of the coolers 110. The outlet pipe 140 is connected to the cooler 110 from the inlet side 3 of the polyethylene reactor 1 via the outlet switching device 150. The outlet switching device 150 is disposed between the outlet pipe 140 and the cooler 110 and is configured to selectively connect the outlet pipe 140 to the cooler outlet pipe 113 of one of the coolers 110. Importantly, according to one embodiment of the present application, the inlet switching device 130 and the outlet switching device 150 are connected to the same cooler 110. This means that at any one operating moment, the process gas stream passes through one and only one cooler 110 .

[0024] The inlet pipe 120 is connected to the exhaust port 2 of the polyethylene reactor 1 for receiving the high-temperature process gas from the reactor. The outlet pipe 140 is connected to the inlet port 3 of the polyethylene reactor for returning the cooled process gas to the reactor.

[0025] The inlet pipe 120 is provided with a shut-off valve 122 to selectively cut off the flow of gas in the inlet pipe 120 . The outlet pipe 140 is provided with a flow valve 142 to steplessly change the flow of gas in the outlet pipe 140 .

[0026] Gas cooling system 100 includes a controller 160. Controller 160 is connected to shutoff valve 122 and flow valve 142 to control the on / off state of shutoff valve 122 and the opening degree of flow valve 142. Controller 160 can be a programmable logic controller (PLC) or other automated control device. By receiving operating instructions or pre-set programs, it enables remote or automatic control of the valves, thereby simplifying switching operations.

[0027] The air inlet switching device 130 and the air outlet switching device 150 both include a fast switching mechanism. Figure 1 and Figure 2 As shown, the cooler inlet pipe 112 of the cooler 110 includes a cooler inlet elbow pipe section 114 and a cooler inlet flange 115 provided at the end of the cooler inlet elbow pipe section 114. The cooler outlet pipe 113 includes a cooler outlet elbow pipe section 116 and a cooler outlet flange 117 provided at the end of the cooler outlet elbow pipe section 116. The inlet pipe 120 is provided with an inlet pipe flange 121 at its end, and the outlet pipe 140 is provided with an outlet pipe flange 141 at its end.

[0028] The intake switching device 130 includes an intake elbow pipe segment 131, an intake elbow pipe segment fastener 132 (e.g., a bolt, nut, stud, locking pin, etc.), and intake elbow pipe flanges 133 provided at both ends of the intake elbow pipe segment 131. One end of the intake elbow pipe segment 131 is rotatably connected to the intake pipe 120 via the intake elbow pipe flange 133 and the intake pipe flange 121. The other end of the intake elbow pipe segment 131 is selectively connected to one of the coolers 110 via the intake elbow pipe flange 133 and the cooler inlet flange 115. The intake elbow pipe segment fastener 132 operably secures the intake elbow pipe flange 133 and the intake pipe flange 121 at one end of the intake elbow pipe segment 131, and operably secures the intake elbow pipe flange 133 and the cooler inlet flange 115 at the other end of the intake elbow pipe segment 131.

[0029] The outlet switching device 150 includes an outlet elbow pipe segment 151, an outlet elbow pipe segment fastener 152, and outlet elbow pipe flanges 153 provided at both ends of the outlet elbow pipe segment 151. One end of the outlet elbow pipe segment 151 is rotatably connected to the outlet pipe 140 via the outlet elbow pipe flange 153 and the outlet pipe flange 141. The other end of the outlet elbow pipe segment 151 is selectively connected to one of the coolers 110 via the outlet elbow pipe flange 153 and the cooler outlet flange 117. The outlet elbow pipe segment fastener 152 operably secures the outlet elbow pipe flange 153 and the outlet pipe flange 141 at one end of the outlet elbow pipe segment 151, and operably secures the outlet elbow pipe flange 153 and the cooler outlet flange 117 at the other end of the outlet elbow pipe segment 151.

[0030] return Figure 1 The gas cooling system 100 includes a cooling water pipe 170 . The cooling water pipe 170 is connected to the coolers 110 and provides a cooling medium (eg, water) to the two coolers 110 .

[0031] The gas cooling system 100 includes a relief valve 181 and a drain pipe 182. The relief valve 181 is provided on the cooler 110 to drain excess coolant from the cooler 110 (e.g., during a hydrostatic test or cleaning). The drain pipe 182 is connected to the relief valve 181 to receive excess coolant and direct it to a safe area.

[0032] Through the above structure, the gas cooling system 100 of the present application realizes the parallel setting and fast switching function of the cooler 110. When one of the coolers 110 is online, the other cooler 110 is in standby state and can be maintained offline (such as cleaning). When the online cooler 110 needs maintenance, the controller 160 is used to control the shut-off valve 122 to cut off the gas flow in the intake pipe 120 and close the flow valve 142. Next, the operator can pull out the intake elbow pipe segment fastener 132 on the intake switching device 130 and the outlet elbow pipe segment fastener 152 on the outlet switching device 150, rotate the intake elbow pipe segment 131 and the outlet elbow pipe segment 151 to the appropriate position, and then reinsert the intake elbow pipe segment fastener 132 and the outlet elbow pipe segment fastener 152 to lock them to switch the process gas flow to the other cooler 110. Finally, the controller 160 opens the stop valve 122 and slowly increases the gas flow in the gas outlet pipe 140 through the flow valve 142, so as to gradually restore the gas supply to the polyethylene reactor 1 after the switch is completed. In this way, the downtime can be greatly shortened, and the maintenance difficulty and safety risks can be reduced.

[0033] As used herein, the singular forms "a," "an," and "the" should be interpreted as meaning "at least one," and therefore, unless expressly stated otherwise, may also include a plurality of entities of the same kind. It should also be understood that the terms "comprise," "include," "includes," and / or "includes" specify the presence of stated features, actions, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, actions, integers, steps, operations, elements, components, and / or groups thereof.

[0034] The specific embodiments described above are only for the purpose of more clearly describing the principles of the present application, wherein each component is clearly shown or described to make the principles of the present application easier to understand. Without departing from the scope of the present application, those skilled in the art can easily make various modifications or changes to the present application, and such modifications or changes should all be included in the scope of patent protection of the present application.

Claims

1. A gas cooling system (100) for cooling process gas in a polyethylene reactor (1), characterized in that: The gas cooling system (100) comprises: Two coolers (110) are arranged in parallel, the coolers (110) comprising a cooler body (111), a cooler inlet pipe (112) connected to an inlet end of the cooler body (111), and a cooler outlet pipe (113) connected to an outlet end of the cooler body (111); an air inlet pipe (120) connected from the outlet side (2) of the polyethylene reactor (1) to the cooler inlet pipe (112) via a recycle gas compressor; an intake switching device (130) disposed between the intake duct (120) and the cooler (110) and configured to selectively connect the intake duct (120) to the cooler inlet duct (112) of one of the coolers (110); an outlet pipe (140) connected from the inlet side (3) of the polyethylene reactor (1) to the cooler outlet pipe (113); and An air outlet switching device (150) is provided between the air outlet pipe (140) and the cooler (110) and is configured to selectively connect the air outlet pipe (140) to the cooler outlet pipe (113) of one of the coolers (110).

2. The gas cooling system (100) according to claim 1, characterized in that The air intake switching device (130) and the air outlet switching device (150) are configured to connect the air intake pipe (120) and the air outlet pipe (140) to the same cooler (110).

3. The gas cooling system (100) according to claim 1, characterized in that The cooler inlet pipe (112) includes a cooler inlet elbow pipe section (114) and a cooler inlet flange (115) provided at an end of the cooler inlet elbow pipe section (114); and The cooler outlet pipe (113) includes a cooler outlet elbow pipe section (116) and a cooler outlet flange (117) arranged at the end of the cooler outlet elbow pipe section (116).

4. The gas cooling system (100) according to claim 3, characterized in that The air intake duct (120) is provided with an air intake duct flange (121) at the end thereof; and The air outlet pipe (140) is provided with an air outlet pipe flange (141) at the end thereof.

5. The gas cooling system (100) according to claim 4, characterized in that The air intake switching device (130) comprises an air intake elbow pipe section (131), an air intake elbow pipe section fastener (132), and air intake elbow pipe flanges (133) arranged at both ends of the air intake elbow pipe section (131); One end of the air intake elbow pipe section (131) is rotatably connected to the air intake pipe (120) via the air intake elbow pipe flange (133) and the air intake pipe flange (121); The other end of the air intake elbow pipe section (131) is selectively connected to one of the coolers (110) through the air intake elbow pipe flange (133) and the cooler inlet flange (115); and The air intake elbow pipe section fastener (132) operably fixes the air intake elbow pipe flange (133) and the air intake pipe flange (121) at one end of the air intake elbow pipe section (131) together, and operably fixes the air intake elbow pipe flange (133) and the cooler inlet flange (115) at the other end of the air intake elbow pipe section (131) together.

6. The gas cooling system (100) according to claim 4, characterized in that The gas outlet switching device (150) comprises a gas outlet elbow pipe section (151), a gas outlet elbow pipe section fastener (152), and gas outlet elbow pipe flanges (153) arranged at both ends of the gas outlet elbow pipe section (151); One end of the gas outlet elbow pipe section (151) is rotatably connected to the gas outlet pipe (140) via the gas outlet elbow pipe flange (153) and the gas outlet pipe flange (141); The other end of the outlet elbow pipe section (151) is selectively connected to one of the coolers (110) through the outlet elbow pipe flange (153) and the cooler outlet flange (117); and The outlet elbow pipe section fastener (152) operably fixes the outlet elbow pipe flange (153) and the outlet pipe flange (141) at one end of the outlet elbow pipe section (151) together, and operably fixes the outlet elbow pipe flange (153) and the cooler outlet flange (117) at the other end of the outlet elbow pipe section (151) together.

7. The gas cooling system (100) according to claim 1, characterized in that A shut-off valve (122) is provided in the air intake pipe (120) to selectively cut off the flow of gas in the air intake pipe (120); and A flow valve (142) is provided in the gas outlet pipeline (140) to steplessly change the gas flow in the gas outlet pipeline (140).

8. The gas cooling system (100) according to claim 7, characterized in that The gas cooling system (100) includes a controller (160); and The controller (160) is connected to the stop valve (122) and the flow valve (142) to control the on / off state of the stop valve (122) and the opening degree of the flow valve (142).

9. The gas cooling system (100) according to claim 1, characterized in that The gas cooling system (100) includes a cooling water pipeline (170); and The cooling water pipe (170) is connected to the cooler (110) to supply cooling water to the cooler (110).

10. The gas cooling system (100) according to claim 1, characterized in that The gas cooling system (100) includes an overflow valve (181) and a drainage pipe (182); The overflow valve (181) is provided on the cooler (110); and The drain pipe (182) is connected to the overflow valve (181) to discharge the cooling water in the cooler (110).

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