Defrosting structure at tail end of low-temperature pressure relief pipe
By designing a specific pipeline structure at the end of the cryogenic pressure relief pipeline in the air separation unit, and using ambient dry air or nitrogen to accelerate the gas flow rate, the problem of icing in the cryogenic pressure relief pipeline was solved, thus improving both safety and economy.
Patent Information
- Application Number
- CN202420604613.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-03-27
- Publication Date
- 2025-01-07
- Estimated Expiration
- 2034-03-27
AI Technical Summary
The cryogenic pressure relief pipelines of existing air separation units are prone to icing at the end, leading to difficulties in pressure relief and safety hazards. Furthermore, they rely on manual cleaning on a regular basis, which requires high levels of management and maintenance expertise.
Design a defrosting structure at the end of a low-temperature pressure relief pipe. Use room temperature dry air or nitrogen to accelerate the gas flow rate through a specific pipe structure to avoid condensation and ice formation. The structure includes a first straight pipe, a 45° elbow, and a second straight pipe connection. The gas supply structure is connected to the gas source.
It effectively increases gas flow rate, prevents condensation and icing, simplifies management, reduces safety hazards, lowers manufacturing costs, and minimizes human intervention.
Smart Images
Figure CN222316700U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of air separation cold boxes, in particular to a defrosting structure at the end of a low-temperature pressure relief pipe. Background Art
[0002] Air separation units and storage tanks use safety valves or bursting discs as pressure relief devices in a closed system. However, safety valves and bursting discs will greatly affect the pressure stability of the system after activation. Safety valve setting or bursting disc replacement is very complicated. Therefore, under normal operating conditions, the design unit usually designs a separate relief pipeline. The relief valve on the relief pipeline is connected to the DCS to relieve pressure in time under slight overpressure.
[0003] Although pressure relief through a control valve can effectively solve the problem of system overpressure and maintain system pressure balance, since the control valve will open to release pressure under a slight overpressure, the pressure relief pressure is usually very low, and the gas flow rate behind the pressure relief valve is usually very low. In some special working conditions, the pressure relief valve will work for a long time and the pressure relief will continue for a long time.
[0004] Because the pressure relief pipe takes a long time to release pressure, the pressure is low, the gas flow rate in the pipeline is slow, and the pressure relief gas comes from a cold box or a low-temperature storage tank, the gas is usually low temperature. When the low-temperature gas with a slow flow rate comes into contact with water vapor in the air, the water vapor will condense and freeze at the end of the pressure relief pipe. As time is long enough, it will form an ice block at the end of the pipe, blocking the discharge pipe, making it difficult to release pressure and creating a danger. And because the pressure relief pipe is usually located at the top of the cold box or the top of the storage tank, the ice block will fall, forming a safety hazard of falling objects from high altitude.
[0005] The existing air separation plant's solution to the above situation mainly relies on regular manual cleaning by maintenance personnel. Such a solution is highly dependent on the air separation plant's management capabilities, has high requirements for maintenance personnel, and is very inconvenient. Utility Model Content
[0006] 1. Technical problems to be solved by the utility model
[0007] The utility model aims to solve the technical problems existing in the prior art and provides a defrosting structure at the end of a low-temperature pressure relief pipe, which can utilize the amount of gas introduced to increase the gas flow rate in the pressure relief pipe at the end of the pressure relief pipe, and the dry air or nitrogen introduced makes the normal temperature gas heat the end of the pressure relief pipe cooled by the gas in the cold box, thereby largely eliminating the possibility of condensation and ice.
[0008] 2. Technical solution
[0009] In order to solve the above problems, the technical solution provided by the utility model is:
[0010] A defrosting structure for the end of a low-temperature pressure relief pipe comprises a first straight pipe, a 45° elbow and a second straight pipe, wherein the first straight pipe and the second straight pipe are both horizontally arranged and connected by the 45° elbow, an air supply structure is connected to the first straight pipe, and a bottom height of the first straight pipe is higher than a top height of the second straight pipe.
[0011] Optionally, the gas supply structure includes a branch pipe platform and a gas supply pipe, the gas supply pipe is connected to the first straight pipe through the branch pipe platform, and the gas supply pipe is connected to a gas source.
[0012] Optionally, the gas source is dry air or nitrogen at room temperature.
[0013] Optionally, the branch pipe is connected to the top of the first straight pipe.
[0014] Optionally, a shut-off valve is provided on the air supply pipe.
[0015] Optionally, a rainproof structure is provided at the end of the second straight pipe.
[0016] Optionally, the end of the second straight pipe is beveled to form the rainproof structure.
[0017] Optionally, the length of the first straight tube is not less than 300 mm, and the length of the second straight tube is not less than 100 mm.
[0018] 3. Beneficial effects
[0019] Compared with the prior art, the technical solution provided by the utility model has the following beneficial effects:
[0020] The defrosting structure at the end of the low-temperature pressure relief pipe uses the amount of gas introduced to increase the gas flow rate in the pressure relief pipe at the end of the pressure relief pipe, and the dry air or nitrogen introduced makes the normal temperature gas, which can heat the end of the pressure relief pipe cooled by the gas in the cold box to largely eliminate the possibility of condensation and icing. Because the normal temperature dry air or nitrogen in the air separation plant is very easy to obtain, there is no economic pressure to use dry air or nitrogen to purge the end of the pressure relief pipe, which can be regarded as zero cost. And because the defrosting structure at the end of the low-temperature pressure relief pipe is extremely simple, the manufacturing cost is basically negligible. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Figure 1 A schematic diagram of a defrosting structure at the end of a low-temperature pressure relief pipe proposed in an embodiment of the utility model;
[0022] 1. First straight pipe; 2. 45° elbow; 3. Second straight pipe; 4. Branch pipe platform; 5. Air supply pipe; 6. Shut-off valve; 7. Rainproof structure. DETAILED DESCRIPTION
[0023] In order to make the purpose, technical solution and advantages of the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. It should be understood that the specific implementation methods described here are only used to explain the utility model and do not limit the protection scope of the utility model.
[0024] It should be noted that when an element is referred to as being "fixed to", "disposed on", "fixed on" or "installed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. Further, when an element is considered to be "fixedly connected to" another element, the two may be fixed in a detachable connection manner or in a non-detachable connection manner, such as socketing, snap-on, one-piece fixation, welding, etc., which can be achieved in the prior art and will not be repeated here. When an element is perpendicular or approximately perpendicular to another element, it means that the ideal state of the two is vertical, but due to the influence of manufacturing and assembly, there may be a certain vertical error. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only implementation method.
[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art in the technical field of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.
[0026] The “first” and “second” involved in the present invention do not represent specific quantities and orders, but are merely used to distinguish names.
[0027] Combined with Figure 1 A defrosting structure at the end of a low-temperature pressure relief pipe in this embodiment comprises a first straight pipe 1, a 45° elbow 2 and a second straight pipe 3. The first straight pipe 1 and the second straight pipe 3 are both horizontally arranged and connected by the 45° elbow 2. An air supply structure is connected to the first straight pipe 1. The air supply structure is used to introduce dry air or nitrogen at room temperature into the first straight pipe 1. The bottom height of the first straight pipe 1 is higher than the top height of the second straight pipe 3 to ensure that condensed water vapor does not enter the air separation device or storage tank. A 45° elbow plus a straight pipe section is used for connection, so that the finished elbow can be simplified in manufacturing, and the straight pipe between the two elbows can flexibly coordinate the height difference between the two straight pipe sections.
[0028] like Figure 1 As shown, the first straight pipe 1 of the defrosting structure at the end of the low-temperature pressure relief pipe is connected behind the pressure relief control valve.
[0029] The defrosting structure at the end of the low-temperature pressure relief pipe uses the amount of gas introduced to increase the gas flow rate in the pressure relief pipe at the end of the pressure relief pipe, and the dry air or nitrogen introduced makes the normal temperature gas, which can heat the end of the pressure relief pipe cooled by the gas in the cold box to largely eliminate the possibility of condensation and icing. Because the normal temperature dry air or nitrogen in the air separation plant is very easy to obtain, there is no economic pressure to use dry air or nitrogen to purge the end of the pressure relief pipe, which can be regarded as zero cost. And because the defrosting structure at the end of the low-temperature pressure relief pipe is extremely simple, the manufacturing cost is basically negligible.
[0030] As a preferred solution of the utility model, the air supply structure includes a branch pipe platform 4 and an air supply pipe 5. The branch pipe platform 4 is connected to one end of the air supply pipe 5. The air supply pipe 5 is connected to the first straight pipe 1 through the branch pipe platform 4. The air supply pipe 5 is connected to the air source. The branch pipe platform 4 is connected to the top of the first straight pipe 1 to facilitate the smooth blowing out of water vapor and avoid moisture backflow.
[0031] As a preferred solution of the utility model, a cut-off valve 6 is provided on the gas supply pipe 5, and the cut-off valve 6 is a manual cut-off valve, so that the air separation device can cut off the gas source under the parking condition.
[0032] As a preferred embodiment of the present invention, a rainproof structure 7 is provided at the end of the second straight tube 3. The end of the second straight tube 3 is beveled at 45° to form the rainproof structure 7. As shown in the figure, the upper end of the end of the second straight tube 3 extends relative to the lower end, and the upper end relative to the extending portion plays a rainproof role.
[0033] As a preferred embodiment of the utility model, the length of the first straight tube 1 is not less than 300 mm, the length of the second straight tube 3 is not less than 100 mm, and the sum of the lengths of the first straight tube 1 and the second straight tube 3 is greater than 400 mm, ensuring that the gas has sufficient time for defrosting and improving gas utilization. In addition, the length of the second straight tube 3 is designed to be relatively short, which facilitates the rapid discharge of condensed gas or condensed liquid.
[0034] The above schematically describes the present invention and its implementation methods, which are not restrictive. The drawings show only one implementation method of the present invention, and the actual structure is not limited thereto. Therefore, if ordinary technicians in this field are inspired by it and design structural methods and embodiments similar to the technical solution without creativity without departing from the purpose of the present invention, they should all fall within the protection scope of the present invention.
Claims
1. A defrosting structure at the end of a low-temperature pressure relief pipe, characterized in that: It includes a first straight pipe, a 45° elbow and a second straight pipe. The first straight pipe and the second straight pipe are both horizontally arranged and connected by the 45° elbow. The first straight pipe is connected to an air supply structure. The bottom height of the first straight pipe is higher than the top height of the second straight pipe.
2. A low-temperature pressure relief pipe end defrosting structure according to claim 1, characterized in that: The air supply structure includes a branch pipe platform and an air supply pipe. The air supply pipe is connected to the first straight pipe through the branch pipe platform, and the air supply pipe is connected to an air source.
3. A low-temperature pressure relief pipe end defrosting structure according to claim 2, characterized in that: The gas source is dry air or nitrogen at room temperature.
4. A low-temperature pressure relief pipe end defrosting structure according to claim 2, characterized in that: The branch pipe platform is connected to the top of the first straight pipe.
5. A low-temperature pressure relief pipe end defrosting structure according to claim 2, characterized in that: A cut-off valve is provided on the air supply pipe.
6. A low-temperature pressure relief pipe end defrosting structure according to claim 1, characterized in that: A rainproof structure is provided at the end of the second straight pipe.
7. A low-temperature pressure relief pipe end defrosting structure according to claim 6, characterized in that: The end of the second straight pipe is beveled to form the rainproof structure.
8. A low-temperature pressure relief pipe end defrosting structure according to any one of claims 1 to 7, characterized in that: The length of the first straight tube is not less than 300 mm, and the length of the second straight tube is not less than 100 mm.