Heavy hydrocarbon-rich natural gas debenzolization system
By adopting a combination design of pre-cooling heat exchanger, pre-cooling unit and adsorption tower in the oil field associated gas treatment system, combined with R507 refrigerant and carbon molecular sieve adsorption method, the high energy consumption and complexity of the debenzene method in the prior art are solved. Problem, efficient benzene removal and heavy hydrocarbon recovery are achieved, which is suitable for low benzene high-heavy components.
Patent Information
- Application Number
- CN202420136750.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-01-19
- Publication Date
- 2024-12-31
- Estimated Expiration
- 2034-01-19
AI Technical Summary
In the prior art, when dealing with natural gas rich in heavy hydrocarbons in the associated gas of oil fields, the debenzene method has problems such as high energy consumption, complex process, and is not suitable for low benzene content and high heavy components, making it difficult to achieve effective purification and equipment safety.
A system including pre-cooling heat exchanger, pre-cooling unit, gas-liquid separator and adsorption tower was designed. R507 is used as a refrigerant and combined with carbon molecular sieve adsorption method to achieve low temperature separation of benzene and recovery of heavy hydrocarbons, which simplifies the process reduces energy consumption and equipment complexity.
The effective removal of benzene is achieved, and the benzene content in the purification gas is reduced to below 10ppm. The system is safe and reliable, and is suitable for treating low benzene content and large recombinant content, and the energy consumption and equipment investment are reduced.
Smart Images
Figure CN222274478U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to a system, in particular to a natural gas debenzening system rich in heavy hydrocarbons, which belongs to the field of gas purification and can be used for purifying oil field associated gas and wellhead natural gas rich in heavy hydrocarbons. Background Art
[0002] Oilfield associated gas is a type of natural gas carried along during the oil extraction process. Its main components are hydrocarbons such as methane, ethane, propane, butane, and pentane, and it has a large number of heavy components. Before the natural gas enters the LNG cold box for liquefaction, the heavy hydrocarbons and impurities such as benzene contained in it must be removed to below the required content to avoid freezing at low temperatures and blocking equipment and pipelines. At present, the commonly used methods for removing benzene from natural gas at home and abroad include adsorption, solvent absorption, mixed refrigerant refrigeration and low-temperature separation, etc.
[0003] When using the solvent absorption method, the commonly used solvent is isopentane, which uses the principle of like dissolves like to absorb the benzene in the associated gas. It is necessary to add an absorbent heating and regeneration system so that the absorbent can be recycled. The disadvantages of this method are that the energy consumption of solvent heating and regeneration is high, and the other is that it will dissolve the heavy hydrocarbons contained in the natural gas, and the solvent level will become higher and higher.
[0004] When using the adsorption method to remove benzene, carbon molecular sieves are mostly used. The removal depth of benzene depends on the type of adsorbent and the regeneration form. The disadvantage of this method is that the process is complicated and it is not very suitable for treating natural gas rich in heavy hydrocarbons. The carbon molecular sieve will adsorb heavy hydrocarbons while adsorbing benzene. The carbon molecular sieve is easily saturated and the regeneration energy consumption is very high. The above two methods are not suitable for treating the situation where the benzene content is low and the content of heavy components in the raw gas components is large.
[0005] Traditional low-temperature separation methods mostly use a two-stage throttling method of mixed refrigerant to cool the raw gas step by step to separate benzene from natural gas. The disadvantage is that when the raw gas composition changes, the refrigerant ratio needs to be adjusted in time, which is relatively complicated; the temperature at the separation point is difficult to control. Once the benzene removal fails to meet the standard, the vehicle will freeze in the deep cooling section and the rewarming time is long, which has a great impact on production. Utility Model Content
[0006] The purpose of the utility model is to overcome the above-mentioned deficiencies in the prior art and to provide a system with reasonable system design, safety and reliability, good debenzening effect, and the recovery of mixed hydrocarbon products in natural gas while debenzening, so as to meet the requirements of subsequent entry into the natural gas liquefaction cold box for debenzening a natural gas rich in heavy hydrocarbons.
[0007] The technical solution adopted by the utility model to solve the above-mentioned problem is: the natural gas debenzenization system rich in heavy hydrocarbons includes a pipeline, and is characterized in that it also includes a precooling heat exchanger, a precooling unit, a gas-liquid separator and an adsorption tower, and the precooling heat exchanger, the precooling unit, the gas-liquid separator and the adsorption tower are all connected through pipelines; the precooling heat exchanger includes a heat exchanger channel one, a heat exchanger channel two and a heat exchanger channel three, one end of the precooling unit is connected to the precooling heat exchanger, and the other end of the precooling unit is connected to the gas-liquid separator, the upper end of the gas-liquid separator is connected to the heat exchanger channel one of the precooling heat exchanger, and the lower end of the gas-liquid separator is connected to the heat exchanger channel three of the precooling heat exchanger; the adsorption tower is connected to the precooling heat exchanger.
[0008] Preferably, the utility model further comprises an adsorption tower heating inlet valve and an adsorption tower heating outlet valve, and the adsorption tower heating inlet valve and the adsorption tower heating outlet valve are respectively arranged at the bottom and the top of the adsorption tower.
[0009] Preferably, the pipelines of the utility model include pipeline 1, pipeline 2, pipeline 3, pipeline 4, pipeline 5, pipeline 6, pipeline 7, pipeline 8, pipeline 9 and pipeline 10. Pipeline 1 enters the heat exchanger channel 1 of the precooling heat exchanger; pipeline 2 enters the precooling unit, and the gas-liquid two phases enter the gas-liquid separator through pipeline 3; pipeline 4 and pipeline 5 enter the heat exchanger channel 3 of the precooling heat exchanger, and then enter pipeline 6; pipeline 7 enters the heat exchanger channel 1 of the precooling heat exchanger, and then enters pipeline 8; the gas phase of pipeline 8 enters the subsequent device through pipeline 10 and pipeline 9.
[0010] Compared with the prior art, the utility model has the following advantages and effects: the overall system design is reasonable, safe and reliable, the oil field associated gas debenzening process is simplified, the device energy consumption is reduced, the equipment is miniaturized and convenient for skid installation, the debenzening effect is good, the benzene content in the purified gas can be reduced to below 10ppm, and the mixed hydrocarbon products in the natural gas can be recovered while debenzening, meeting the requirements of subsequent entry into the natural gas liquefaction cold box. It is particularly suitable for processing such a situation where the benzene content is low and the heavy component content in the raw gas components is large. BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Figure 1 It is a schematic diagram of the system structure of an embodiment of the utility model.
[0012] In the figure: precooling heat exchanger 1, precooling unit 2, gas-liquid separator 3, adsorption tower 4; pipeline L, pipeline one 5, pipeline two 6, pipeline three 7, pipeline four 8, pipeline five 9, pipeline six 10, pipeline seven 11, pipeline eight 12, pipeline nine 13, pipeline ten 14; adsorption tower heating inlet valve 15, adsorption tower heating outlet valve 16; heat exchanger channel one 101, heat exchanger channel two 102, heat exchanger channel three 103. DETAILED DESCRIPTION
[0013] The present invention will be further described in detail below with reference to the accompanying drawings and through examples. The following examples are provided to explain the present invention, but the present invention is not limited to the following examples.
[0014] Example
[0015] See also Figure 1 The heavy hydrocarbon-rich natural gas debenzening system of this embodiment includes a pipeline L, a precooling heat exchanger 1, a precooling unit 2, a gas-liquid separator 3 and an adsorption tower 4, and the precooling heat exchanger 1, the precooling unit 2, the gas-liquid separator 3 and the adsorption tower 4 are all connected by the pipeline L.
[0016] The precooling heat exchanger 1 in this embodiment includes a heat exchanger channel 1 101, a heat exchanger channel 2 102 and a heat exchanger channel 3 103. One end of the precooling unit 2 is connected to the precooling heat exchanger 1, and the other end of the precooling unit 2 is connected to the gas-liquid separator 3. The upper end of the gas-liquid separator 3 is connected to the heat exchanger channel 1 101 of the precooling heat exchanger 1, and the lower end of the gas-liquid separator 3 is connected to the heat exchanger channel 3 103 of the precooling heat exchanger 1; the adsorption tower 4 is connected to the precooling heat exchanger 1.
[0017] The adsorption tower heating inlet valve 15 and the adsorption tower heating outlet valve 16 in this embodiment are respectively arranged at the bottom and the top of the adsorption tower 4 .
[0018] The pipeline L in this embodiment includes pipeline 1 5, pipeline 2 6, pipeline 3 7, pipeline 4 8, pipeline 5 9, pipeline 6 10, pipeline 7 11, pipeline 8 12, pipeline 9 13 and pipeline 14.
[0019] The specific steps of the natural gas debenzenization system rich in heavy hydrocarbons in this embodiment are as follows: the benzene-containing associated gas enters the heat exchanger channel 2 102 of the precooling heat exchanger 1 through the pipeline 1 5, exchanges heat with the cold flow in the heat exchanger channel 1 101 and the heat exchanger channel 3 103 in the precooling heat exchanger 1, and is cooled to a certain temperature; enters the precooling unit 2 through the pipeline 2 6, and is cooled to a set temperature; the gas-liquid two-phase enters the gas-liquid separator 3 through the pipeline 3 7, and is separated into gas-liquid two-phase by gravity in the gas-liquid separator 3; the liquid phase passes through the regulating valve through the pipeline 4 8, and is reduced in pressure to the storage tank pressure, The gas enters the heat exchanger channel three 103 of the precooling heat exchanger 1 through the pipeline five 9, and enters the pipeline six 10 after being reheated to room temperature; the gas phase enters the heat exchanger channel one 101 of the precooling heat exchanger 1 through the pipeline seven 11, and enters the pipeline eight 12 after being reheated to room temperature. Under normal circumstances or when the adsorption tower 4 is regenerated, the gas phase exiting the pipeline eight 12 enters the subsequent device through the pipeline ten 14 and the pipeline nine 13; when the precooling unit 2 fails or the refrigeration effect is not good, the gas phase exiting the pipeline eight 12 enters the adsorption tower 4, removes the benzene in the associated gas, and then enters the subsequent device through the pipeline nine 13.
[0020] After a period of time, when the adsorption tower 4 is saturated with adsorption, the regenerated gas heated by the front-end dehydration system enters from the bottom of the adsorption tower through the adsorption tower heating inlet valve 15, exits the device through the adsorption tower heating outlet valve 16 at the top of the adsorption tower, and goes to the regenerated gas cooler of the front-end dehydration system. After regeneration is completed, it can be put into use again.
[0021] In this embodiment, taking into account the characteristics that natural gas has a large content of heavy components and benzene is easily soluble in organic solvents, a low-temperature separation process using R507 as a refrigerant is combined with a carbon molecular sieve adsorption method to remove trace benzene from natural gas rich in heavy hydrocarbons, while also recovering C3+ in natural gas.
[0022] In this embodiment, the carbon molecular sieve is used as a backup measure and is only used when the temperature of the preceding low-temperature separation device fluctuates, and is heated and regenerated depending on the adsorption saturation situation; this method has a simple process, low energy consumption, small equipment investment, strong adaptability to fluctuations in the content of heavy components, fast freezing and reheating, and high removal accuracy.
[0023] This embodiment is only applicable to oilfield associated gas and wellhead natural gas rich in heavy hydrocarbons, and the natural gas by-products can be recovered while removing benzene. This system is not applicable when the heavy hydrocarbon content in the natural gas is low.
[0024] Through the above description, those skilled in the art can already implement it.
[0025] In addition, it should be noted that the shapes and names of the parts and components of the specific embodiments described in this specification may be different, and the above content described in this specification is only an example of the structure of the utility model. All equivalent changes or simple changes made based on the structure, features and principles described in the patent concept of the utility model are included in the protection scope of the utility model patent. Technicians in the technical field of the utility model can make various modifications or supplements to the specific embodiments described or replace them in a similar manner, as long as they do not deviate from the structure of the utility model or exceed the scope defined by the claims, they should all fall within the protection scope of the utility model.
Claims
1. A system for removing benzene from a natural gas rich in heavy hydrocarbons, comprising a pipeline (L), characterized in that: The invention also comprises a precooling heat exchanger (1), a precooling unit (2), a gas-liquid separator (3) and an adsorption tower (4); the precooling heat exchanger (1), the precooling unit (2), the gas-liquid separator (3) and the adsorption tower (4) are all connected via a pipeline (L); the precooling heat exchanger (1) comprises a heat exchanger channel 1 (101), a heat exchanger channel 2 (102) and a heat exchanger channel 3 (103); one end of the precooling unit (2) is connected to the precooling heat exchanger (1); the other end of the precooling unit (2) is connected to the gas-liquid separator (3); the upper end of the gas-liquid separator (3) is connected to the heat exchanger channel 1 (101) of the precooling heat exchanger (1); and the lower end of the gas-liquid separator (3) is connected to the heat exchanger channel 3 (103) of the precooling heat exchanger (1); and the adsorption tower (4) is connected to the precooling heat exchanger (1).
2. The system for removing benzene from a natural gas rich in heavy hydrocarbons according to claim 1, characterized in that: It also comprises an adsorption tower heating inlet valve (15) and an adsorption tower heating outlet valve (16), wherein the adsorption tower heating inlet valve (15) and the adsorption tower heating outlet valve (16) are respectively arranged at the bottom and the top of the adsorption tower (4).
3. The system for removing benzene from a natural gas rich in heavy hydrocarbons according to claim 1, characterized in that: The pipeline (L) comprises pipeline 1 (5), pipeline 2 (6), pipeline 3 (7), pipeline 4 (8), pipeline 5 (9), pipeline 6 (10), pipeline 7 (11), pipeline 8 (12), pipeline 9 (13) and pipeline 10 (14). Pipeline 1 (5) enters the heat exchanger channel 1 (101) of the precooling heat exchanger (1); pipeline 2 (6) enters the precooling unit (2), and the gas-liquid two-phase enters the gas-liquid separator (3) through pipeline 3 (7); pipeline 4 (8) and pipeline 5 (9) enter the heat exchanger channel 3 (103) of the precooling heat exchanger (1), and then enter pipeline 6 (10); pipeline 7 (11) enters the heat exchanger channel 1 (101) of the precooling heat exchanger (1), and then enters pipeline 8 (12); the gas phase of pipeline 8 (12) enters the subsequent device through pipeline 10 (14) and pipeline 9 (13).