Oil removal separator for compressed coal bed gas
By combining a coalescing filter and a double-blade mist eliminator in a separation system, the problem of lubricating oil contamination in the dehydration equipment was solved, achieving efficient oil-water separation, improving coalbed methane quality and extending the lifespan of the dehydration equipment, and reducing operating and maintenance costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SHANXI LANYAN COALBED METHANE GRP CO LTD
- Filing Date
- 2025-05-13
- Publication Date
- 2026-04-21
AI Technical Summary
During the compression and transportation of coalbed methane, lubricating oil contaminates the dehydration equipment, leading to a decrease in dehydration efficiency and affecting the quality of coalbed methane and the efficiency of subsequent processes.
A two-stage filtration and separation system combining a coalescing filter and a double-blade mist eliminator is adopted. The lubricating oil is separated through physical filtration and coalescence, and the micro oil droplets and emulsified oil sludge are removed by dynamic separation.
It significantly reduces the oil content in coalbed methane, extends the lifespan of dehydration equipment, improves gas quality, reduces operating and maintenance costs, adapts to different pressures and flow rates, and ensures the quality of coalbed methane and the smooth operation of subsequent processes.
Smart Images
Figure CN224141793U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of coalbed methane purification technology, specifically relating to a compressed coalbed methane oil separator. Background Technology
[0002] In the compression and transportation of coalbed methane, the compressor, as a crucial piece of equipment, requires a large amount of lubricating oil for adequate lubrication to reduce wear and ensure efficient operation. However, contact between the lubricating oil and the coalbed methane is inevitable during compression, resulting in a small amount of lubricating oil entering the next process stage with the coalbed methane. During repeated replacements of triethylene glycol and molecular sieves in the dehydration equipment, it was found that the surfaces of these dehydrating agents were coated with black lubricating oil, causing the triethylene glycol to become black and viscous, significantly reducing its water absorption effect and even affecting dehydration efficiency. Lubricating oil contamination of the dehydrating agents in the dehydration system reduces its efficiency and degrades the quality of the coalbed methane, making it unable to meet the requirements of subsequent processes.
[0003] Therefore, to prevent lubricating oil from contaminating the dehydration equipment and to improve the dehydration effect, it is necessary to take effective measures to separate the lubricating oil from the coalbed methane after compression. This not only protects the dehydration equipment and extends its service life, but also improves the quality of the coalbed methane and the efficiency of subsequent processes. Utility Model Content
[0004] To solve the above-mentioned technical problems, this utility model provides a compressed coalbed methane oil separator.
[0005] The technical solution adopted by this utility model is a compressed coalbed methane oil separator, including a tank body. A partition is set inside the tank body to divide the upper part of the tank body. A coalescing filter is set in the upper part. A circumferential baffle is set on the inner side wall of the middle part of the tank body. A double-bladed mist eliminator is set in the circumferential baffle. The bottom of the tank body is an oil storage tank. An air inlet is set on the upper outer wall of the tank body. An exhaust port is set on the middle outer wall of the tank body corresponding to the inside of the circumferential baffle. Compressed coalbed methane enters from the air inlet, is filtered by the coalescing filter and the double-bladed mist eliminator, and is discharged from the exhaust port. A coarse filter drain port is set on the upper outer wall of the tank body near the partition. A fine filter drain port connected to the oil storage tank is set on the bottom outer wall of the tank body.
[0006] Furthermore, the coarse filter drain outlet and the fine filter drain outlet are connected to the main drain pipe, and the main drain pipe is equipped with a sampling port.
[0007] Furthermore, a level gauge is installed at the bottom of the tank.
[0008] Furthermore, the circumferential enclosure is a square frame.
[0009] Furthermore, the double-blade fog eliminator is composed of a blade fog eliminator, which has a structure of multiple double-blade fog eliminators arranged side by side. Each blade has a wavy or bent structure, forming a series of concave and convex channels.
[0010] The compressed coalbed methane oil separator of this invention has the following beneficial effects:
[0011] 1. Highly efficient oil-water separation: This device employs a combined two-stage filtration and separation system consisting of a coalescing filter and a double-bladed mist eliminator. Through physical filtration and coalescence, it effectively separates the lubricating oil from the compressed coalbed methane gas stream, significantly reducing the oil content. This not only extends the service life of the dehydration equipment but also reduces the water dew point of the coalbed methane, improving its quality.
[0012] 2. The oil removal effect is remarkable. This device effectively removes tiny oil droplets and emulsified oil contaminants through a combination of coalescence separation and dynamic separation. Even in coalbed methane with high oil content, this device can still efficiently remove oil, ensuring continuous gas quality.
[0013] 3. It can operate at low cost and high efficiency. The coalescing filter element and double-sided blades have a long service life, resulting in low equipment maintenance costs. Compared with other traditional separation devices, this device does not consume additional energy, saving energy consumption. At the same time, due to its simple structure and long-life materials, it further reduces operating and maintenance costs.
[0014] 4. High adaptability and stability: This device has wide adaptability and can be applied to coalbed methane with different pressures, flow rates, and oil content. It can operate stably during both coalbed methane extraction and gathering processes, ensuring the quality of the coalbed methane and the smooth progress of subsequent processes.
[0015] 5. Energy-free and environmentally friendly: This device uses mechanical and physical separation technology, requiring no external energy support. It avoids the high energy consumption problem common in traditional oil-water separation devices, reduces the environmental burden, and is a highly efficient and environmentally friendly separation device. Attached Figure Description
[0016] Figure 1 This is a schematic diagram of the structure of this utility model;
[0017] Figure 2 This is an installation diagram of this utility model.
[0018] In the diagram: 1. Tank body; 11. Air inlet; 12. Exhaust outlet; 13. Coarse filter drain outlet; 14. Fine filter drain outlet; 2. Baffle; 3. Coalescing filter; 4. Peripheral enclosure; 5. Double-bladed mist eliminator; 6. Oil storage tank; 7. Main drain pipe; 71. Sampling port; 8. Level gauge. Detailed Implementation
[0019] To better understand the purpose, structure, and function of this utility model, a compressed coalbed methane oil separator of this utility model will be described in further detail below with reference to the accompanying drawings.
[0020] like Figure 1 As shown, a compressed coalbed methane oil separator includes a tank 1. A partition 2 is installed inside the tank 1 to divide the upper part of the tank 1. A coalescing filter 3 is installed in the upper part. A square frame-shaped circumferential enclosure 4 is installed on the inner side wall of the middle part of the tank 1. A double-bladed mist eliminator 5 is installed in the circumferential enclosure 4. The bottom of the tank 1 is an oil storage tank 6. An air inlet 11 is provided on the upper outer wall of the tank 1. An exhaust port 12 is provided on the middle outer wall of the tank 1 corresponding to the interior of the circumferential enclosure 4. Compressed coalbed methane enters from the air inlet 11, is filtered by the coalescing filter 3 and the double-bladed mist eliminator 5, and is discharged from the exhaust port 12. A coarse filter drain port 13 is provided on the upper outer wall of the tank 1 near the partition. A fine filter drain port 14 connected to the oil storage tank 6 is provided on the bottom outer wall of the tank 1.
[0021] In this embodiment, the filter element of the coalescing filter 3 is an integrated spiral-formed thick filter element with a high internal density, made of oleophilic and hydrophobic fiber material. This allows for better coalescence of lubricating oil in the coalbed methane and the filtration of some of the lubricating oil, thus initially reducing the oil content of the coalbed methane.
[0022] The double-blade mist eliminator 5 consists of aerodynamically efficient blade mist eliminators with high structural strength. Its structure comprises multiple parallel double-blade designs, each blade featuring a wavy or zigzag structure, forming a series of concave and convex channels. This increases the tortuosity of the coalbed methane flow path while providing a larger surface area to capture droplets. It utilizes physical processes such as changes in coalbed methane flow direction, adsorption, coalescence, and gravity within the stainless steel blades to achieve the separation of oil droplets and coalbed methane.
[0023] The specific separation principle is as follows: Coalbed methane entrained with droplets enters the blade channel of the double-loop blades at a certain flow rate. Due to the bending design of the blades, the coalbed methane is forced to change direction multiple times. The droplet density is greater than that of the coalbed methane. When the airflow direction changes abruptly, the droplets cannot change direction quickly with the coalbed methane due to inertia and directly impact the blade surface. The double-loop structure (concave-convex design) on the blade surface can effectively trap the impacting droplets, preventing them from being entrained by the airflow again, thus achieving oil-gas separation. The captured droplets gather into larger droplets on the blade surface and eventually flow along the blade wall to the oil storage tank under the action of gravity.
[0024] Compared to large-area filter cartridges, the double-blade system is more suitable for situations where the coalbed methane volume is large and the installation space is limited. It works perfectly with the upper coalescing filter 3 to effectively remove 99% of lubricating oil droplets of 1μm and above from the coalbed methane.
[0025] This invention utilizes a two-stage filtration and separation system combining a coalescing filter element and double-blade composite to effectively separate and discharge the lubricating oil contained in coalbed methane. This extends the service life of the dehydrating agent in subsequent dehydration equipment, reduces the water dew point of the coalbed methane by 3°C to 5°C, and improves the quality of the coalbed methane. This invention features high efficiency, low energy consumption, and good adaptability, significantly improving the quality of coalbed methane, ensuring the stable operation of the coalbed methane gathering and transportation system, reducing the maintenance frequency of the dehydration system, and lowering overall operating costs.
[0026] like Figure 2 As shown, an oil separator is installed after the coalbed methane compressor and before the dehydration equipment. The processing flow of the compressed coalbed methane after the oil separator is as follows: ① The coalbed methane compressed by the compressor enters the coalescing filter 3 at the top of the oil separator, where small particles of lubricating oil are coalesced and some large particles of lubricating oil are filtered out. ② After passing through the coalescing filter 3, it enters the double-blade demister 5 at the bottom of the oil separator, where oil droplets in the coalbed methane are separated and discharged. ③ Coalbed methane dehydration: The oil-removed coalbed methane is dehydrated, generally using triethylene glycol dehydration or molecular sieve dehydration, to adsorb the moisture in the coalbed methane, so that the water dew point of the coalbed methane reaches the national Class I gas standard, that is, under the pressure and temperature conditions at the natural gas junction, there should be no liquid substances.
[0027] Specifically, the coalbed methane compressed by the compressor first enters the coalescing filter 3. The gas carrying lubricating oil enters the interior from the outside of the coalescing filter element. During this process, the lubricating oil in the coalbed methane coalesces and grows. The larger particles of lubricating oil that are filtered out are discharged through the coarse filter drain pipe 13.
[0028] After coalescence, the coalbed methane enters the aerodynamic double-blade mist eliminator 5 through the filter element support tube of the coalescence filter element. In this system, the oil droplets in the coalbed methane are separated by the blade mist eliminator. The liquid collection tank at the bottom of the mist eliminator assembly flows to the oil storage tank 6 at the bottom of the tank body 1 through the downcomer. The lubricating oil in the oil storage tank 6 is discharged through the fine filter drain pipe 14.
[0029] The lubricating oil separated by the coalescing filter 3 and the double-blade mist eliminator 5 is discharged through the coarse filter drain port 13 and the fine filter drain port 14, respectively, and collected into the main drain pipe 7. A sampling port 71 is made on the main drain pipe 7 to periodically sample and analyze the composition of the discharged liquid and to analyze the oil removal effect of the oil separator.
[0030] A level gauge 8 is installed at the bottom of the tank 1 to check the liquid level in the oil storage tank 6 and determine whether the drain pipe is working properly.
[0031] After installing the oil separator, 99% of lubricating oil droplets of 1μm and above in compressed coalbed methane are effectively removed, improving the quality of the coalbed methane. It has already been applied in four plants. Taking one plant processing approximately 1.5 million cubic meters of coalbed methane per day as an example, about 8-10 liters of lubricating oil are discharged daily. Before the upgrade, all of this lubricating oil went into the dehydration equipment. The upgrade significantly improves the dehydration effect of the subsequent dehydration equipment, making it easier for the water dew point of the coalbed methane leaving the plant to meet the national Class I gas standard.
[0032] Furthermore, it reduces the contamination of the dehydrating agents (triethylene glycol and molecular sieves) by the lubricating oil carried by the coalbed methane. Before installing the oil separator, a certain plant needed to replace the triethylene glycol annually to ensure dehydration efficiency. After installing the oil separator, the triethylene glycol only needs to be replaced every two years, which also reduces the pressure on the filter elements of the dehydration system. The extended service life of the triethylene glycol, molecular sieves, and dehydration filter elements has generated certain economic benefits.
[0033] It is understood that this utility model has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of this utility model. Furthermore, under the teachings of this utility model, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of this utility model. Therefore, this utility model is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the protection scope of this utility model.
Claims
1. A compressed coal bed gas oil removal separator characterized by, The tank includes a tank body (1), which is divided into an upper part by a partition (2). A coalescing filter (3) is installed in the upper part. A circumferential enclosure (4) is installed on the inner side wall of the middle part of the tank body (1). A double-bladed mist eliminator (5) is installed in the circumferential enclosure (4). The bottom of the tank body (1) is an oil storage tank (6). An air inlet (11) is provided on the upper outer wall of the tank body (1). An exhaust port (12) is provided on the inner side of the circumferential enclosure (4) of the middle outer wall of the tank body (1). Compressed coalbed methane enters from the air inlet (11), is filtered by the coalescing filter (3) and the double-bladed mist eliminator (5), and is discharged from the exhaust port (12). A coarse filter drain port (13) is provided on the upper outer wall of the tank body (1) near the partition (2). A fine filter drain port (14) is provided on the bottom outer wall of the tank body (1) and connects to the oil storage tank (6).
2. The compressed coal bed gas oil removal separator of claim 1, wherein, The coarse filter drain outlet (13) and the fine filter drain outlet (14) are connected to the main drain pipe (7), and the main drain pipe (7) is equipped with a sampling port (71).
3. The compressed coal bed gas oil removal separator of claim 1, wherein, A level gauge (8) is installed at the bottom of the tank (1).
4. The compressed coal bed gas oil removal separator of claim 1, wherein, The circumferential enclosure (4) is a square frame.
5. The compressed coal bed gas oil separator according to any one of claims 1 to 4, characterized in that, The double-blade fog eliminator (5) consists of a blade fog eliminator with a structure of multiple double-blade fog eliminators arranged side by side. Each blade has a wavy or bent structure, forming a series of concave and convex channels.