An online detection system for circulating gas in an oxalic acid production unit
By designing an online detection system for circulating gas in the oxalic acid production device that integrates collection, transportation, detection and analysis, the problems of long cycles of circulating gas detection and analysis, the problem of long data analysis cycles, data lag and safety hazards in the existing technology is solved, real-time and safe data acquisition is achieved, and the needs of modern industrial production are met.
Patent Information
- Application Number
- CN202420702059.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-07
- Publication Date
- 2025-04-01
- Estimated Expiration
- 2034-04-07
AI Technical Summary
In the prior art, the detection and analysis period of the circulating gas in the oxalic acid production device is too long, resulting in data lag, and accurate data cannot be provided in real time, which poses safety risks.
A oxalic acid production device circulating gas online detection system is designed, integrating acquisition, transportation, detection and analysis, and real-time detection and analysis of circulating gas is achieved through components such as gas-liquid separation tank, membrane filter, precision filter, infrared analyzer, etc.
It greatly shortens the sampling and analysis cycle, makes the data more timely, provides real-time data guarantee for the exploration of process indicators, eliminates the safety hazards brought by external circulation gas, and meets the needs of modern industrial production.
Smart Images
Figure CN222704511U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of gas detection and analysis, in particular to an online detection system for circulating gas of an oxalic acid production device. Background Art
[0002] Oxalic acid, also known as oxalic acid, is an important organic chemical raw material. It is widely used in fine chemicals to prepare various dyes, medicines, important solvents, extractants and various intermediates. At present, the methods for industrial production of oxalic acid mainly include sodium formate method, oxidation method, carbonyl synthesis method, ethylene glycol oxidation method, propylene oxidation method, carbon monoxide coupling method, etc. Among them, methyl nitrite, as one of the intermediate products of carbon monoxide coupling method, is also the raw material for producing the intermediate product dimethyl oxalate. In the oxalic acid production device, the content of methyl nitrite is the key factor to achieve stable operation of the whole process. Therefore, it is necessary to detect and analyze the circulating gas in the oxalic acid production device in real time.
[0003] At present, the traditional sampling and analysis method requires the recycling gas generated in the oxalic acid production device to be collected, and then sent to the laboratory for detection and analysis using chromatography, and the production process indicators are adjusted based on the data obtained. However, the biggest drawback of this method is that the cycle is too long. One detection takes at least half an hour, which makes the data have a large lag, and cannot provide accurate data in real time. It is impossible to provide real-time data guarantee for the exploration of process indicators, and it can no longer meet the needs of modern industrial production. In addition, the frequent collection and transportation of recycled gas also poses certain safety hazards. Utility Model Content
[0004] In order to make up for the deficiencies of the prior art, the utility model provides an online detection system for circulating gas of an oxalic acid production device. The system has a reasonable structural design, is easy to operate, and integrates collection, transportation, detection, and analysis. The detection and analysis of circulating gas can be realized without separately collecting circulating gas, which greatly shortens the sampling and analysis cycle, makes data more timely, and provides real-time data guarantee for the exploration of process indicators. At the same time, the safety hazards brought by external circulating gas are effectively eliminated, the needs of modern industrialized production are met, and the problems existing in the prior art are solved.
[0005] The technical solution adopted by the utility model to solve the above technical problems is:
[0006] An online detection system for circulating gas of an oxalic acid production device comprises a gas-liquid separation tank, which is connected to the oxalic acid production device via a pipeline, an injection shut-off valve and a first pressure reducing valve are sequentially arranged on the pipeline between the oxalic acid production device and the gas-liquid separation tank, a first liquid discharge valve is arranged on the pipeline at the liquid discharge port of the gas-liquid separation tank, an exhaust port at the top of the gas-liquid separation tank is sequentially connected in series with a membrane filter, a precision filter, an injection flow meter, an infrared analyzer, and a buffer tank via a pipeline, the infrared analyzer is connected to a DCS via a line, a second liquid discharge valve is arranged on the pipeline at the liquid discharge port of the buffer tank, the exhaust port at the top of the buffer tank is connected to a venturi pump via a pipeline, the exhaust port of the venturi pump is connected to a recovery device via a pipeline, and a purge mechanism is arranged on the pipeline between the membrane filter and the precision filter.
[0007] Optionally, the purge mechanism includes a nitrogen gas supply device, the exhaust port pipeline of the nitrogen gas supply device is connected to the pipeline between the membrane filter and the precision filter, and a nitrogen shut-off valve, a second pressure reducing valve and a nitrogen purge valve are sequentially connected in series on the pipeline.
[0008] Optionally, a pipeline connected to the Venturi pump is provided on the pipeline between the nitrogen cut-off valve and the second pressure reducing valve, and a third pressure reducing valve is provided on the pipeline.
[0009] Optionally, a first three-way ball valve is provided on the pipeline between the membrane filter and the precision filter, another outlet of the first three-way ball valve is connected to the second three-way ball valve via a pipeline, and the other two outlets of the second three-way ball valve are connected to the standard gas cylinder via pipelines respectively.
[0010] Optionally, steam heating is provided on the pipeline between the oxalic acid production device and the infrared analyzer, electric heating is coated on the pipeline between the sampling flow meter and the infrared analyzer, and a thermal insulation layer is wrapped around the outside of the electric heating.
[0011] Optionally, the infrared analyzer is arranged in an analysis room, and a carbon monoxide alarm, a toxic gas alarm and an explosion-proof fan are arranged in the analysis room.
[0012] The utility model adopts the above technical scheme, and has the advantages of reasonable structural design, simple operation, integration of collection, transportation, detection and analysis, and can realize detection and analysis of circulating gas without separately collecting circulating gas, which greatly shortens the sampling and analysis cycle, makes data more timely, and provides real-time data guarantee for the exploration of process indicators. At the same time, it effectively eliminates the safety hazards brought by external circulating gas and meets the needs of modern industrialized production. BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Figure 1 It is a schematic diagram of the structure of the utility model;
[0014] In the figure, 1. gas-liquid separation tank; 2. injection shut-off valve; 3. first pressure reducing valve; 4. first drain valve; 5. membrane filter; 6. precision filter; 7. injection flow meter; 8. infrared analyzer; 9. buffer tank; 10. second drain valve; 11. venturi pump; 12. nitrogen shut-off valve; 13. second pressure reducing valve; 14. nitrogen purge valve; 15. third pressure reducing valve; 16. first three-way ball valve; 17. second three-way ball valve; 18. calibration gas cylinder; 19. steam heating; 20. electric heating. DETAILED DESCRIPTION
[0015] In order to clearly illustrate the technical features of the present solution, the present invention is described in detail below through specific implementation methods and in conjunction with the accompanying drawings. In the following description, many specific details are described to facilitate a full understanding of the present application. However, the present application can also be implemented in other ways different from those described herein. Therefore, the protection scope of the present application is not limited by the specific embodiments disclosed below.
[0016] In addition, in the description of the present application, it should be understood that the terms "center", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first" and "second" are used only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.
[0017] 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, they can be fixedly connected, detachably connected, or integrated. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to the specific circumstances. In the description of this specification, the descriptions with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" and the like mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.
[0018] As shown in the figure, in this embodiment, an online detection system for circulating gas of an oxalic acid production device includes a gas-liquid separation tank 1, which is connected to the oxalic acid production device via a pipeline, and an injection shut-off valve 2 and a first pressure reducing valve 3 are sequentially provided on the pipeline between the oxalic acid production device and the gas-liquid separation tank 1, and a first liquid discharge valve 4 is provided on the pipeline at the liquid discharge port position of the gas-liquid separation tank 1, and the exhaust port at the top of the gas-liquid separation tank 1 is sequentially connected in series with a membrane filter 5, a precision filter 6, an injection flow meter 7, an infrared analyzer 8, and a buffer tank 9 via a pipeline, and the infrared analyzer 8 is connected to a DCS via a line, and a second liquid discharge valve 10 is provided on the pipeline at the liquid discharge port position of the buffer tank 9, and the exhaust port at the top of the buffer tank 9 is connected to a venturi pump 11 via a pipeline, and the exhaust port of the venturi pump 11 is connected to a recovery device via a pipeline, and a purge mechanism is provided on the pipeline between the membrane filter 5 and the precision filter 6.
[0019] Optionally, the purging mechanism includes a nitrogen gas supply device, the exhaust port pipeline of the nitrogen gas supply device is connected to the pipeline between the membrane filter 5 and the precision filter 6, and a nitrogen shut-off valve 12, a second pressure reducing valve 13 and a nitrogen purge valve 14 are sequentially arranged in series on the pipeline.
[0020] Optionally, a pipeline connected to the venturi pump 11 is provided on the pipeline between the nitrogen cut-off valve 12 and the second pressure reducing valve 13, and a third pressure reducing valve 15 is provided on the pipeline. The nitrogen cut-off valve 12 and the third pressure reducing valve 15 are first opened, and the second pressure reducing valve 13 is closed, and nitrogen is blown into the pipeline behind the venturi pump 11 through the venturi pump 11, so as to remove the circulating gas. This process is mainly used for repairing the venturi pump 11.
[0021] Optionally, a first three-way ball valve 16 is provided on the pipeline between the membrane filter 5 and the precision filter 6, and the other outlet of the first three-way ball valve 16 is connected to the second three-way ball valve 17 via a pipeline, and the other two outlets of the second three-way ball valve are respectively connected to the standard gas cylinder 18 via pipelines. The two standard gas cylinders 18 contain zero gas and span gas respectively, and the zero gas or span gas enters through the second three-way ball valve 17 and the first three-way ball valve 16 in turn. The standard gas is introduced regularly to calibrate the analyzer, so that the zero drift of the infrared analyzer 8 can be corrected in time.
[0022] Optionally, steam heating 19 is provided on the pipeline between the oxalic acid production device and the infrared analyzer 8, electric heating 20 is coated on the pipeline between the injection flowmeter 7 and the infrared analyzer 8, and a thermal insulation layer is wrapped around the outside of the electric heating 20.
[0023] Optionally, the infrared analyzer 8 is arranged in an analysis room, and a carbon monoxide alarm, a toxic gas alarm, and an explosion-proof fan are arranged in the analysis room. When there is a gas leak in the pipeline, the carbon monoxide alarm and the toxic gas alarm will sound an alarm and upload it to the DCS to remind the operator to handle it in time.
[0024] When the system is in operation, the oxalic acid circulating gas produced by the oxalic acid production device enters the gas-liquid separation tank 1 through the injection shut-off valve 2 and the first pressure reducing valve 3 in turn. The water in the circulating gas is discharged outward through the first drain valve 4 through the gas-liquid separation tank 1, and the dehydrated circulating gas passes through the membrane filter 5 (the mode filter 5 is mainly to further remove the water in the circulating gas), the precision filter 6 (the precision filter 6 is mainly to remove impurities in the circulating gas, such as the crystal particles and the fine droplets contained), and the injection flow meter 7 in turn, and enters the infrared analyzer 8. The infrared analyzer 8 analyzes and measures the content of each component in the circulating gas, and transmits the result to the DCS (distributed control system is referred to as DCS, which adopts the design principle of decentralized control functions, centralized display operations, and taking into account the design principles of division and autonomy and comprehensive coordination). The circulating gas after the analysis enters the buffer tank 9, which not only realizes the secondary gas-liquid separation of the circulating gas, but also stabilizes the gas flow of the sample. The moisture in the circulating gas is discharged to the outside through the second liquid discharge valve 10, and the gas is sent to the recovery equipment for storage through the Venturi pump 11.
[0025] When the system stops working, first close the injection shut-off valve 2, then open the nitrogen shut-off valve 12, the second pressure reducing valve 13, and the nitrogen purge valve 14. The nitrogen generated by the nitrogen supply device passes through the nitrogen shut-off valve 12, the second pressure reducing valve 13, and the nitrogen purge valve 14 in turn, and enters the pipeline between the membrane filter 5 and the infrared analyzer 8. The nitrogen purge is used to prevent residual circulating gas from remaining in the infrared analyzer 8. It should be noted that the purge time is not less than 15 minutes. After the purge is completed, the gas in the pipeline needs to be recalibrated. First, close the injection shut-off valve 2, and turn the first three-way ball valve 16 to connect the calibration gas cylinder 18 to the pipeline. The second three-way ball valve 17 can be turned to choose to calibrate the pipeline with zero gas or range gas. It has a reasonable structural design and is easy to operate. It integrates collection, transportation, detection and analysis. It can detect and analyze circulating gas without collecting circulating gas separately, which greatly shortens the sampling and analysis cycle, makes the data more timely, and provides real-time data guarantee for the exploration of process indicators. At the same time, it effectively eliminates the safety hazards brought by external circulating gas, meets the needs of modern industrial production, and solves the problems existing in the existing technology.
[0026] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions described in the above embodiments can still be modified, or some or all of the technical features can be replaced by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and description of the present invention. For those skilled in the art, any replacement improvements or changes made to the implementation methods of the present invention are within the protection scope of the present invention.
[0027] The matters not described in detail in the present invention are all known technologies to those skilled in the art.
Claims
1. An online detection system for circulating gas of an oxalic acid production device, characterized in that: The invention comprises a gas-liquid separation tank, which is connected with an oxalic acid production device via a pipeline. An injection shut-off valve and a first pressure reducing valve are sequentially arranged on the pipeline between the oxalic acid production device and the gas-liquid separation tank. A first liquid discharge valve is arranged on the pipeline at the liquid discharge port of the gas-liquid separation tank. An exhaust port on the top of the gas-liquid separation tank is sequentially connected in series with a membrane filter, a precision filter, an injection flow meter, an infrared analyzer and a buffer tank via a pipeline. The infrared analyzer is connected with a DCS via a line. A second liquid discharge valve is arranged on the pipeline at the liquid discharge port of the buffer tank. The exhaust port on the top of the buffer tank is connected with a venturi pump via a pipeline. The exhaust port of the venturi pump is connected with a recovery device via a pipeline. A purge mechanism is arranged on the pipeline between the membrane filter and the precision filter.
2. The online detection system for circulating gas of an oxalic acid production device according to claim 1 is characterized in that The purging mechanism includes a nitrogen gas supply device, the exhaust port pipeline of the nitrogen gas supply device is connected to the pipeline between the membrane filter and the precision filter, and a nitrogen cut-off valve, a second pressure reducing valve and a nitrogen purge valve are sequentially connected in series on the pipeline.
3. The online detection system for circulating gas of an oxalic acid production device according to claim 2 is characterized in that: A pipeline connected to the Venturi pump is provided on the pipeline between the nitrogen cut-off valve and the second pressure reducing valve, and a third pressure reducing valve is provided on the pipeline.
4. The online detection system for circulating gas of an oxalic acid production device according to claim 2, characterized in that: A first three-way ball valve is provided on the pipeline between the membrane filter and the precision filter, another outlet of the first three-way ball valve is connected to the second three-way ball valve via a pipeline, and the other two outlets of the second three-way ball valve are connected to the standard gas cylinder via pipelines respectively.
5. The online detection system for circulating gas of an oxalic acid production device according to claim 1 is characterized in that: Steam heating is provided on the pipeline between the oxalic acid production device and the infrared analyzer, electric heating is provided on the pipeline between the sampling flow meter and the infrared analyzer, and a thermal insulation layer is provided on the outside of the electric heating.
6. The online detection system for circulating gas of an oxalic acid production device according to claim 5, characterized in that: The infrared analyzer is arranged in an analysis room, and a carbon monoxide alarm, a toxic gas alarm and an explosion-proof fan are arranged in the analysis room.