A modular system and method for removing impurities from a desulfurized amine solution
By using a modular system and personalized impurity removal methods, the performance degradation caused by impurities in amine solutions has been solved, achieving efficient and low-cost impurity removal and ensuring the stability of the natural gas purification process.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- PETROCHINA CO LTD
- Filing Date
- 2022-09-21
- Publication Date
- 2026-07-24
AI Technical Summary
Existing technologies are insufficient for targeted and low-cost removal of impurities from amine solutions, leading to decreased desulfurization performance and equipment corrosion, which in turn affects the stability of natural gas purification production.
The system employs a modular design, including a filtration module, a defoaming module, a desalination module, and an amine salt conversion module. Modules can be selectively connected or disconnected based on the type of impurity. Combined with conductivity detection and pH monitoring, personalized impurity removal can be achieved.
It effectively reduces impurity content, saves time and costs, quickly restores the desulfurization performance of amine solutions, and ensures the stable operation of the natural gas purification process.
Smart Images
Figure CN117776422B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of desulfurization of amine solutions in natural gas purification plants and oil refineries, specifically to a modular system and method for removing impurities from desulfurized amine solutions. Background Technology
[0002] The amine process is the primary method for desulfurization and decarbonization of natural gas, refinery gas, and other industrial gases. Natural gas purification plants widely employ this method. Sulfur-containing natural gas must undergo desulfurization and decarbonization purification before it can be delivered to users as a qualified commodity. Therefore, the natural gas purification process is a crucial link in natural gas production and supply. The dominant desulfurization process is the amine process. However, the amine desulfurization and decarbonization solution (referred to as amine solution) is easily contaminated and deteriorated by residues from upstream drilling, cementing, acidizing, and corrosion prevention operations during natural gas purification, leading to decreased performance of the amine solution and problems such as equipment corrosion, foaming, and shutdowns. Since the amine desulfurization solution may be subject to different contamination levels at different times and under different conditions, the types of impurities in the amine solution will vary. Therefore, how to effectively and cost-effectively remove impurities from the amine solution in a targeted manner, while ensuring its desulfurization performance, has become a bottleneck restricting stable production in the natural gas purification process. Summary of the Invention
[0003] The purpose of this invention is to propose a modular system and method for removing impurities from desulfurized amine solutions. This invention modularizes each removal function, allowing for customized selection of removal modules based on the specific types of impurities in the desulfurized amine solution, thus saving time, energy consumption, and material costs during the impurity removal process. Furthermore, it provides operational parameters for impurity removal from desulfurized amine solutions. During each removal cycle, the impurity content in the amine solution decreases to a certain extent, thereby gradually increasing the processing capacity of the amine solution and completing the removal of impurities in the amine solution with maximum efficiency, speed, and optimal time.
[0004] To achieve the above objectives, the present invention adopts the following technical solution:
[0005] The present invention provides a modular system for removing impurities from desulfurized amine liquid, the system comprising: a desulfurized amine liquid pipeline, a regenerated amine liquid pipeline, a filtration module, a defoaming module, a desalination module, and an amine salt conversion module;
[0006] The inlet of the filtration module is connected to the desulfurized amine liquid pipeline, and the outlet is connected to the inlet of the defoaming module and the inlet of the desalination module, respectively. The outlet of the defoaming module is connected to the regenerated amine liquid pipeline and the inlet of the desalination module, respectively. The outlet of the desalination module is connected to the inlet of the amine salt conversion module. The outlet of the amine salt conversion module is connected to the regenerated amine liquid pipeline. The connecting pipelines between the modules can be controlled to be connected or closed.
[0007] The function of the desulfurized amine liquid pipeline is to input the desulfurized amine liquid to be regenerated into the system of the present invention; the function of the regenerated amine liquid pipeline is to output the amine liquid after impurity removal and regeneration.
[0008] The function of the filtration module is to filter and remove suspended solids. Specifically, it can be a polypropylene fiber membrane filter with a filtration accuracy of 1-3μm. If the pressure difference of the filter increases during use, the filter element can be replaced directly.
[0009] The defoaming module removes foaming impurities, such as long-chain carboxylic acids, ethers, and amides, from the desulfurized amine solution, solving the problem of foaming and liquid blockage caused by these impurities. The main body of the defoaming module can be a packed defoaming tower, which uses a defoaming agent with specific pore sizes to physically and selectively adsorb and remove foaming impurities; it also includes corresponding pipelines, pumps, and other equipment.
[0010] The desalination module removes heat-stable salts from the amine solution, solving the problems of equipment corrosion and scale formation caused by the deterioration products of heat-stable salts in the amine solution. The main unit of the desalination module can be a packed desalination tower loaded with ion exchange resin, through which heat-stable salts are adsorbed and removed. It also includes corresponding pipelines, mixers, pumps, and other equipment.
[0011] The amine salt conversion module converts inorganic heat-stable salts into heat-stable amine salts. The main unit of the module can be a packed conversion tower loaded with adsorbent, which converts the inorganic heat-stable salts into heat-stable amine salts, solving the problem of decreased desulfurization performance of regenerated amine solutions. It also includes corresponding pipelines, storage tanks, pumps, and other equipment.
[0012] The adsorbent comprises a polymer with electrophilic groups, which adsorbs and protonates alkanolamine molecules, then reacts with an inorganic heat-stable salt to directionally convert them into a heat-stable amine salt. The heat-stable amine salt is then converted to alkanolamine and water via ion exchange, avoiding the formation of inorganic bases (OH- ions are exchanged out during the adsorption and removal of heat-stable salts by ion exchange resins). — After the amine solution is regenerated, the desulfurization performance is restored to the level of fresh amine solution.
[0013] The heat-stable salts in amine solutions are divided into inorganic heat-stable salts and organic heat-stable salts (i.e., heat-stable amine salts). The desalination module uses ion exchange resin to remove heat-stable salts from the amine solution, which can be divided into: 1) the process of removing inorganic heat-stable salts, where the inorganic heat-stable salts react with OH groups on the ion exchange resin. — Exchange, cations are adsorbed, OH — 1) The amine solution is displaced, causing the pH value of the amine solution to increase and the desulfurization performance of the amine solution to deteriorate; 2) During the removal of organic heat-stable salts, the amines displaced after exchanging with the ion exchange resin are free amines, which will not affect the pH value of the amine solution. At the same time, during the removal of organic heat-stable salts, the H in the adsorbent is also removed.+ The OH groups that are exchanged out during the removal of inorganic heat-stable salts are also exchanged out. - Neutralization restores the pH value of the amine desulfurization solution. Therefore, after using the desalting module, the removal of inorganic thermally stable salts leads to an increase in the pH value of the amine solution. This invention incorporates an amine salt conversion module after the desalting module. This module adsorbs and protonates amine molecules, then reacts with the inorganic thermally stable salts to directionally convert them into thermally stable amine salts, thus restoring the pH value of the amine solution. This solves the problem of decreased performance of the desulfurized amine solution caused by the commonly used ion exchange resin for removing thermally stable salts.
[0014] The system of this invention can select the appropriate removal module based on the specific types of impurities in the desulfurized amine solution, saving time, energy consumption, and material costs during the impurity removal process. Specifically, in practical applications, the system of this invention can selectively employ three schemes based on the specific impurities in the desulfurized amine solution: a complete removal scheme, a scheme for removing only heat-stable salt impurities, and a scheme for removing only foaming impurities.
[0015] When the complete removal scheme is adopted, the desulfurized amine solution passes through the filtration module, defoaming module, desalting module and amine salt conversion module in sequence.
[0016] When using a scheme that only removes heat-stable salt impurities, the desulfurized amine solution is passed sequentially through a filtration module, a desalination module, and an amine salt conversion module.
[0017] When using a method that only removes foaming impurities, the desulfurized amine solution is passed sequentially through a filtration module and a defoaming module.
[0018] Corresponding to the system of the present invention, the removal system selectively employs three interconnection schemes based on the specific impurities in the desulfurized amine solution:
[0019] Complete removal scheme: The connecting pipelines between the filtration module, defoaming module, desalination module and amine salt conversion module are connected in sequence;
[0020] Solution for removing heat-stable salt impurities only: The connecting pipelines between the filtration module, desalination module, and amine salt conversion module are connected in sequence; the connecting pipelines between the defoaming module and the filtration module and desalination module are closed.
[0021] Solution for removing only foaming impurities: The connecting pipeline between the filtration module and the defoaming module is connected; the connecting pipeline between the desalination module and the defoaming module is closed.
[0022] According to the system of the present invention, preferably, a conductivity meter and a pH monitor are connected to the outlet of the amine salt conversion module. The conductivity meter detects the removal effect of heat-stable salts in the amine solution, and the pH monitor assists in monitoring the removal of impurities and the cleaning of the regenerated solution in the adsorbent, such as the pH change when demineralized water is used to remove alkaline regenerated solution, or the pH change when amine solution is used to remove demineralized water.
[0023] According to the system of the present invention, preferably, the degassing module is provided with a first regeneration unit; when the degassing module reaches saturation, the degassing module is regenerated through the first regeneration unit. The desalination module is provided with a second regeneration unit; when the desalination module reaches saturation, the desalination module is regenerated through the second regeneration unit. The amine salt conversion module is provided with a third regeneration unit; when the amine salt conversion module reaches saturation, the amine salt conversion module is regenerated through the third regeneration unit.
[0024] The determination of whether each module has reached saturation is based on the removal characteristics of the removal agent in each module and the impurity content in the desulfurized amine solution. The removal capacity is determined, and the removal time for one cycle is specified. Under a certain capacity, when the impurity removal time reaches the specified time, the impurity removal operation is suspended, and the system enters the regeneration mode to complete the regeneration of the modules that need to be regenerated.
[0025] This invention controls the operation of the entire system by controlling the processing volume and processing time; and uses a conductivity meter and a pH monitor as auxiliary monitoring.
[0026] Another aspect of the present invention provides a method for removing impurities from a modular desulfurized amine solution. The method uses the above system and, depending on the specific impurities in the desulfurized amine solution, selectively employs three schemes: a complete removal scheme, a scheme for removing only heat-stable salt impurities, and a scheme for removing only foaming impurities.
[0027] Complete removal scheme: The desulfurized amine solution is passed sequentially through the filtration module, defoaming module, desalting module, and amine salt conversion module;
[0028] A scheme for removing only heat-stable salt impurities involves passing the desulfurized amine solution sequentially through the filtration module, desalination module, and amine salt conversion module.
[0029] Solution for removing only foaming impurities: The desulfurized amine solution is passed sequentially through the filtration module and the defoaming module.
[0030] After each removal cycle is completed, the impurity removal operation is paused, and the system enters regeneration mode to complete the regeneration of the defoaming module, desalting module, and amine salt conversion module.
[0031] In the complete removal scheme, as each removal cycle is completed, the impurity content in the desulfurized amine solution continuously decreases. The removal of impurities in the desulfurized amine solution involves the following operating parameters: the total volume of desulfurized amine solution in the desulfurization system is represented by Q, the desulfurized amine solution processing capacity is represented by p, and the impurity content is represented by i. Then:
[0032] The amount of desulfurized amine solution processed in the nth (n≥2) cycle, p n (unit: m) 3 ):
[0033]
[0034] The impurity content i in the desulfurization solution during the nth (n≥2) cycle n (unit%):
[0035]
[0036] The total time t for impurity removal from the desulfurized amine solution up to the nth (n≥2) cycle n (unit: h):
[0037]
[0038] Because the regeneration frequencies of the desalination module, defoaming module, and amine salt conversion module are inconsistent, [n / 4] is included in this formula, where square brackets indicate taking the integer part, i.e.:
[0039] The first cycle [1 / 4] = 0
[0040] ...
[0041] The 4th cycle [4 / 4] = 1
[0042] The 5th cycle [5 / 4] = 1
[0043] ...
[0044] The 8th cycle [8 / 4] = 2
[0045] In the formula, 3 includes the regeneration time of the degassing module (1.6 h) and the regeneration time of the amine salt conversion module (1.4 h).
[0046] The total volume of desulfurized amine solution processed up to the nth (n≥2) cycle is P:
[0047]
[0048] i1 is the initial impurity content in the desulfurized amine solution measured experimentally; p1 is the initial amine solution reactivation treatment capacity obtained based on i1 and the adsorption capacity of the adsorbent; the adsorbent here refers to the adsorbent in each of the defoaming module, desalination module and amine salt conversion module in the removal scheme.
[0049] The adsorbent in the degassing module can be, for example, one or a mixture of any of the non-polar or weakly polar adsorbent resins.
[0050] The adsorbent for the desalination module can be, for example, a gel-type strong basic anion exchange resin.
[0051] An example of an adsorbent for an amine salt conversion module may be a cation exchange resin.
[0052] The amine solution in a desulfurization system typically ranges from tens to hundreds of cubic meters. The system of this invention processes approximately ten cubic meters of amine solution per cycle. If the impurity content in the amine solution is high, the amount of amine solution reactivated in one cycle may be even less. Only a small amount of desulfurized amine solution in the desulfurization system can be reactivated per cycle. After reactivation, the amine solution returns to the desulfurization system, where it mixes with unreactivated amine solution and is recycled. Therefore, the impurity content of the amine solution in the desulfurization system normally decreases continuously with each cycle of amine reactivation. This allows for rapid calculation of the impurity content of the amine solution in different cycles, facilitating operation. Based on the calculation, it can be estimated which cycle of reactivation will reduce the impurity content of the amine solution to the desired value, allowing for analysis at that cycle. This also saves labor costs.
[0053] For example, the total desulfurization amine liquid volume in the desulfurization system is Q = 160m³. 3 i1 = 1%, p1 = 4m 3 ;
[0054] Period 1: i1 = 1%, p1 = 4m 3 ;
[0055] After the first cycle of revival, the impurity content in the desulfurized amine solution is i2 = ((160-4)×1%) / 160 = 0.975%; in cycle 2: i2 = 0.975%, p2 = (1%×4) / 0.975% = 4.103m 3
[0056] After the second cycle of revival, the impurity content in the desulfurized amine solution is i3 = (160 - 4.103) × 0.975% / 160 = 0.95%.
[0057] The defoaming module, desalination module, and amine salt conversion module stop impurity removal and enter regeneration mode when the impurity content in the desulfurized amine solution or the amount of co-treated desulfurized amine solution reaches the required level. However, the regeneration frequency of these three modules is different. For example, the defoaming module only needs to be regenerated once every 3 or 4 regenerations of the desalination module. That is, when the desalination module is regenerated for the 3rd or 4th time, the defoaming module and the amine salt conversion module begin their first regeneration. In this invention, one regeneration of the desalination module constitutes one cycle; taking complete removal as an example:
[0058] Cycle 1: The amine solution is reactivated through all modules. When the impurity content in the desulfurized amine solution or the amount of desulfurized amine solution co-treated reaches the required level, the desalination module begins to regenerate.
[0059] Cycle 2: The amine solution is reactivated through all modules. When the impurity content in the desulfurized amine solution or the amount of desulfurized amine solution co-treated reaches the required level, the desalination module begins to regenerate.
[0060] Cycle 3: The amine solution is reactivated through all modules. When the impurity content in the desulfurized amine solution or the amount of desulfurized amine solution co-treated reaches the required level, the desalination module begins to regenerate.
[0061] Cycle 4: The amine solution is regenerated through all modules. When the impurity content in the desulfurized amine solution or the amount of desulfurized amine solution co-treated reaches the required level, the desalination, defoaming, and conversion modules are regenerated in sequence.
[0062] Cycle 5: The amine solution is reactivated through all modules. When the impurity content in the desulfurized amine solution or the amount of desulfurized amine solution co-treated reaches the required level, the desalination module begins to regenerate.
[0063] ...
[0064] In the heat-stable salt removal scheme, the impurity content in the desulfurized amine solution continuously decreases with the completion of each removal cycle. The impurity removal in the desulfurized amine solution involves the following operating parameters: the total desulfurized amine solution volume in the desulfurization system is represented by Q, the desulfurized amine solution processing capacity is represented by p, and the heat-stable salt impurity content is represented by i. Then:
[0065] The amount of desulfurized amine solution processed in the nth (n≥2) cycle, p n (unit: m) 3 ):
[0066]
[0067] The impurity content i in the desulfurization solution during the nth (n≥2) cycle n (unit%):
[0068]
[0069] The total time t for impurity removal from the alcohol desulfurization amine solution to the nth (n≥2) cycle n (unit: h):
[0070]
[0071] The total volume of desulfurized amine solution processed up to the nth (n≥2) cycle is P (unit: m³). 3 ):
[0072]
[0073] In the defoaming impurity removal scheme, the impurity content in the desulfurized amine solution continuously decreases with the completion of each removal cycle. The removal of impurities from the desulfurized amine solution involves the following operating parameters: the total desulfurized amine solution volume in the desulfurization system is represented by Q, the desulfurized amine solution treatment capacity is represented by p, and the foaming impurity content is represented by i. Then:
[0074] The amount of desulfurized amine solution processed in the nth (n≥2) cycle, p n (unit: m) 3 ):
[0075]
[0076] The impurity content i in the desulfurization solution during the nth (n≥2) cycle n (unit%):
[0077]
[0078] The total time t for impurity removal from the desulfurized amine solution up to the nth (n≥2) cycle n (unit: h):
[0079] t n = n × 1.6 -------------------(11)
[0080] The total volume of desulfurized amine solution processed up to the nth (n≥2) cycle is P (unit: m³). 3 ):
[0081]
[0082] During the impurity removal process, the impurity content in the amine solution decreases with each removal cycle. This allows for a gradual increase in the amount of impurities removed from the desulfurized amine solution per cycle, maximizing efficiency and speed in impurity removal. Furthermore, it provides a direct and simple way to monitor the impurity content and the amount of amine solution with removed impurities after a certain removal time. The impurity removal operation can be stopped when the required levels of impurities or the amount of amine solution removed are reached. A conductivity meter and pH monitor are used as auxiliary monitoring methods throughout the process.
[0083] According to the removal method of the present invention, after each cycle is completed, the impurity removal operation is paused and the system enters the regeneration mode. According to the regeneration cycle of each module, the defoaming module, the desalting module and the amine salt conversion module are regenerated through the first regeneration unit, the second regeneration unit and the third regeneration unit, respectively.
[0084] Preferably, after each cycle is completed, the desalination module is regenerated, and the defoaming module and the amine salt conversion module are regenerated once every 3-4 regenerations of the desalination template.
[0085] When the impurity content in the desulfurized amine solution or the amount of desulfurized amine solution co-treated reaches the required level, the operation of removing impurities from the desulfurized amine solution shall be stopped.
[0086] According to the removal method of the present invention, a conductivity meter and a pH meter are used as auxiliary monitoring means.
[0087] The positive effects of this invention include:
[0088] For all natural gas purification plants and refineries' desulfurization amine solutions, modular functions enable customized impurity removal. This saves time, energy, and material costs during the impurity removal process. Furthermore, based on the operating parameters for impurity removal in the amine solution, the processing capacity of each cycle of amine solution can be gradually increased to complete the removal of impurities in the amine solution with maximum efficiency, speed, and optimal time. Attached Figure Description
[0089] Figure 1 This is a schematic diagram of a modular desulfurization amine solution impurity removal system and method according to an embodiment of the present invention.
[0090] Explanation of reference numerals in the attached figures:
[0091] 1-Filtering module, 2-Defoaming module, 3-Desalination module, 4-Amine salt conversion module, 5-First regeneration unit, 6-Second regeneration unit, 7-Third regeneration unit, 8-Conductivity detector, 9-pH monitor, 10-Desulfurized amine liquid pipeline, 11-Regenerated amine liquid pipeline. Detailed Implementation
[0092] To more clearly illustrate the present invention, the following description, in conjunction with preferred embodiments, further clarifies the invention. Those skilled in the art should understand that the specific descriptions below are illustrative rather than restrictive, and should not be construed as limiting the scope of protection of the present invention.
[0093] The modular desulfurization amine solution impurity removal system of the present invention is as follows: Figure 1 As shown, the system includes: a desulfurized amine liquid pipeline 10, a regenerated amine liquid pipeline 11, a filtration module 1, a defoaming module 2, a desalination module 3, and an amine salt conversion module 4.
[0094] The inlet of the filtration module 1 is connected to the desulfurized amine liquid pipeline 10, and the outlet is connected to the inlet of the defoaming module 2 and the inlet of the desalination module 3, respectively; the outlet of the defoaming module 2 is connected to the regenerated amine liquid pipeline 11 and the inlet of the desalination module 3, respectively; the outlet of the desalination module 3 is connected to the inlet of the amine salt conversion module 4; and the outlet of the amine salt conversion module 4 is connected to the regenerated amine liquid pipeline 11.
[0095] The desulfurized amine solution to be regenerated is input into the system through the desulfurized amine solution pipeline 10; the amine solution after processing and impurity removal and regeneration is output through the regenerated amine solution pipeline 11.
[0096] Filter module 1 is used to filter and remove suspended solids. Specifically, it can be a polypropylene fiber membrane filter with a filtration accuracy of 1-3μm.
[0097] Defoaming module 2 is used to remove foaming impurities, such as long-chain carboxylic acids, ethers, and amides, from the desulfurized amine solution, solving the problem of foaming and liquid blockage caused by foaming impurities. The main unit of defoaming module 2 can be a packed defoaming tower, which can physically and selectively adsorb and remove foaming impurities through defoaming agents with specific pore sizes; it also includes corresponding pipelines, pumps, and other equipment.
[0098] Furthermore, the degassing module 2 is also provided with a first regeneration unit 5; when the degassing module 2 reaches saturation, it is regenerated through the first regeneration unit 5. Specifically, the degassing module 2 can be regenerated by rinsing it with an organic regeneration liquid through the first regeneration unit 5. An exemplary organic regeneration liquid is an organic solvent, such as methanol, ethanol, isopropanol, acetone, etc., which exchanges the foaming impurities adsorbed in the degassing agent through a high-concentration organic solution.
[0099] Desalination module 3 is used to remove heat-stable salts from amine solutions, solving the problems of equipment corrosion and scale formation caused by the deterioration products of heat-stable salts in amine solutions. Its main unit can be a packed desalination tower loaded with ion exchange resin, through which heat-stable salts are adsorbed and removed. It also includes corresponding pipelines, mixers, pumps, and other equipment.
[0100] Furthermore, the desalination module 3 is also equipped with a second regeneration unit 6; when the desalination module 3 reaches saturation, it is regenerated through the second regeneration unit 6. Specifically, the desalination module 3 can be regenerated by rinsing it with an alkaline regeneration solution through the second regeneration unit 6. The alkaline regeneration solution can be, for example, an aqueous solution of NaOH or KOH.
[0101] The amine salt conversion module 4 is used to convert inorganic heat-stable salts into heat-stable amine salts. Its main unit can be a packed conversion tower loaded with adsorbent, which converts the inorganic heat-stable salts into heat-stable amine salts, solving the problem of decreased desulfurization performance of regenerated amine solution. It also includes corresponding pipelines, storage tanks, pumps, and other equipment.
[0102] Furthermore, the amine salt conversion module 4 is also equipped with a third regeneration unit 7; when the amine salt conversion module 4 reaches saturation, it is regenerated through the third regeneration unit 7. Specifically, regeneration is achieved by flushing the amine salt conversion module 4 with an acidic regeneration solution through the third regeneration unit 7, using a relatively high concentration of H₂O₂. +Ions are used to regenerate the adsorbent through displacement. An example of an acidic regeneration solution is hydrochloric acid.
[0103] This invention incorporates an amine salt conversion module 4 after the desalination module 3. This module adsorbs and protonates alcohol amine molecules, then reacts them with inorganic, heat-stable salts to directionally convert them into heat-stable amine salts, restoring the pH value of the amine solution. This solves the problem of decreased performance of desulfurized amine solutions caused by the commonly used ion exchange resins for removing heat-stable salts.
[0104] Furthermore, a conductivity meter 8 is connected to the outlet of the amine salt conversion module 4 to monitor the removal effect of thermally stable salt impurities in the amine solution. A pH meter 9 is also connected to the outlet of the amine salt conversion module 4 to assist in monitoring the impurity removal effect and the cleaning status of the regenerated liquid, ensuring that the regenerated liquid is not introduced into the desulfurization system.
[0105] The connecting pipelines between the various modules can be controlled to be connected or closed, thereby achieving different connection paths. This allows for the personalized selection of removal modules based on the specific types of impurities in the desulfurized amine solution, saving time, energy consumption, and material costs during the impurity removal process.
[0106] Specifically, in practical applications, the system of the present invention can selectively adopt three schemes according to the specific impurities in the desulfurized amine solution: a complete removal scheme, a scheme for removing only heat-stable salt impurities, and a scheme for removing only foaming impurities.
[0107] When using the full removal scheme, the desulfurized amine solution is sequentially passed through the filtration module 1, the defoaming module 2, the desalting module 3, and the amine salt conversion module 4.
[0108] When using a scheme that only removes heat-stable salt impurities, the desulfurized amine solution is sequentially passed through filtration module 1, desalination module 3, and amine salt conversion module 4.
[0109] When using a method that only removes foaming impurities, the desulfurized amine solution is passed sequentially through filter module 1 and defoaming module 2.
[0110] Example 1
[0111] This embodiment uses the above system to perform a complete removal scheme, including the following steps:
[0112] The desulfurized amine solution passes through the following modules in sequence: filtration module 1, defoaming module 2, desalination module 3, and amine salt conversion module 4.
[0113] The initial operation is carried out according to the set desulfurization amine solution treatment volume and single cycle removal time.
[0114] After a removal cycle reaches saturation, the defoaming module 2, desalting module 3, and amine salt conversion module 4 are regenerated sequentially.
[0115] The desulfurized amine solution throughput is denoted by p, the impurity content by i, and the total desulfurized amine solution volume in the desulfurization system by Q. During the complete removal process, the throughput p is changed sequentially for each cycle according to the operating parameters. n And based on the impurity content i in the nth period n Alternatively, if the required amount of amine desulfurization solution P is processed in the nth cycle, the entire impurity removal system operation will be terminated. The specific calculation formula is as follows:
[0116] The impurity content i1 in the desulfurization amine solution during the first cycle was determined experimentally, and the treatment capacity p1 of the desulfurization amine solution during the first cycle was obtained based on i1 and the adsorption capacity of the adsorbent. Taking the desulfurization solution of a natural gas purification plant as an example, the amine solution volume Q in its desulfurization system is 160 m³. 3 i1 = 1%, p1 = 4m 3 ;
[0117] Impurity content i2 in the second cycle of desulfurization system:
[0118]
[0119] The second cycle's desulfurized amine solution processing capacity p2:
[0120]
[0121] The total time t for impurity removal from the desulfurized amine solution in the second cycle n :
[0122]
[0123] The total volume of desulfurized amine solution processed in the second cycle is P:
[0124]
[0125] The calculations for the nth cycle follow the same pattern, based on the impurity content i in the nth cycle. n Alternatively, if the required amount of amine desulfurization solution P is processed in the nth cycle, the entire impurity removal system operation is terminated.
[0126] In this process, the desalination module 3 is regenerated after each cycle, and the defoaming module 2 and the amine salt conversion module 4 are regenerated together with the desalination module 3 after the fourth cycle; and so on.
[0127] The entire process is monitored using a conductivity meter and a pH meter. The conductivity meter can monitor the total thermally stable salts. When the conductivity begins to rise during the regeneration of the desulfurized amine solution, it indicates that the adsorbent is gradually becoming saturated, and the system needs to enter regeneration mode.
[0128] Example 2
[0129] This embodiment uses the above system to perform a scheme that removes only stable salt impurities, including the following steps:
[0130] The desulfurized amine solution passes through the following modules in sequence: filtration module 1, desalination module 3, and amine salt conversion module 4.
[0131] Initial operation is performed based on the set desulfurization amine solution processing capacity and single-cycle removal time. After one removal cycle reaches saturation, desalination module 3 and amine salt conversion module 4 are regenerated sequentially.
[0132] The desulfurized amine solution throughput is represented by p, and the impurity content is represented by i. During the process of removing only stable salt impurities, the throughput p is changed sequentially for each cycle according to the operating parameters. n And based on the impurity content i in the nth period n Alternatively, the total amount of amine desulfurization solution P processed in the nth cycle may be sufficient. If the requirements are met, the entire impurity removal system operation is terminated. The entire process utilizes a conductivity meter and pH monitor as auxiliary monitoring methods. The specific calculation formula is as follows:
[0133] The impurity content i1 in the desulfurization amine solution during the first cycle was determined experimentally, and the treatment capacity p1 of the desulfurization amine solution during the first cycle was obtained based on i1 and the adsorption capacity of the adsorbent. Taking the desulfurization solution of a natural gas purification plant as an example, the amine solution volume Q in its desulfurization system is 160 m³. 3 i1 = 1%, p1 = 4m 3 ;
[0134] Impurity content i2 in the second cycle of desulfurization system:
[0135]
[0136] The second cycle's desulfurized amine solution processing capacity p2:
[0137]
[0138] The total time t for impurity removal from the desulfurized amine solution in the second cycle n :
[0139]
[0140] The total volume of desulfurized amine solution processed in the second cycle is P:
[0141]
[0142] The calculations for the nth cycle follow the same pattern, based on the impurity content i in the nth cycle. n Alternatively, if the required amount of amine desulfurization solution P is processed in the nth cycle, the entire impurity removal system operation is terminated.
[0143] In this process, the desalination module 3 is regenerated after each cycle, and the amine salt conversion module 4 is regenerated together with the desalination module 3 after the fourth cycle; and so on.
[0144] The entire process is monitored using a conductivity meter and a pH meter. The conductivity meter can monitor the total thermally stable salts. When the conductivity begins to rise during the regeneration of the desulfurized amine solution, it indicates that the adsorbent is gradually becoming saturated, and the system needs to enter regeneration mode.
[0145] Example 3
[0146] This embodiment uses the above system to perform a defoaming-only impurity removal scheme, including the following steps:
[0147] The desulfurized amine solution passes through the following modules in sequence: filtration module 1 and defoaming module 2.
[0148] The initial operation is performed based on the set amine solution processing capacity and single-cycle removal time. After reaching saturation in one removal cycle, the degassing module 2 is regenerated.
[0149] The throughput of the amine desulfurization solution is represented by p, and the impurity content is represented by i. In the process of removing only foaming impurities, the throughput p for each cycle is changed sequentially according to the operating parameters. n And based on the impurity content i in the nth period n Alternatively, the total amount of amine desulfurization solution P processed in the nth cycle may be sufficient. If the requirements are met, the entire impurity removal system operation is terminated. The entire process utilizes a conductivity meter and pH monitor as auxiliary monitoring methods. The specific calculation formula is as follows:
[0150] The impurity content i1 in the desulfurization amine solution during the first cycle was determined experimentally, and the treatment capacity p1 of the desulfurization amine solution during the first cycle was obtained based on i1 and the adsorption capacity of the adsorbent. Taking the desulfurization solution of a natural gas purification plant as an example, the amine solution volume Q in its desulfurization system is 160 m³. 3 i1 = 1%, p1 = 4m 3 ;
[0151] Impurity content i2 in the second cycle of desulfurization system:
[0152]
[0153] The second cycle's desulfurized amine solution processing capacity p2:
[0154]
[0155] The total time t for impurity removal from the desulfurized amine solution in the second cycle n :
[0156] t n =n × 1.6 = 2 × 1.6 = 3.2h
[0157] The total volume of desulfurized amine solution processed in the second cycle is P:
[0158]
[0159] The calculations for the nth cycle follow the same pattern, based on the impurity content i in the nth cycle. n Alternatively, if the required amount of amine desulfurization solution P is processed in the nth cycle, the entire impurity removal system operation is terminated.
[0160] Among them, the degassing module 2 is regenerated after every 4 cycles.
[0161] The above three embodiments propose three different impurity removal schemes based on the specific impurities in the desulfurized amine solution, thereby achieving three functions of impurity removal in the desulfurized amine solution.
[0162] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. For those skilled in the art, other variations or modifications can be made based on the above description. It is impossible to exhaustively list all the implementation methods here. All obvious variations or modifications derived from the technical solutions of the present invention are still within the protection scope of the present invention.
Claims
1. A method for removing impurities from a modular desulfurized amine solution, characterized in that, The removal method is performed using the following system; The system includes: a desulfurized amine liquid pipeline, a regenerated amine liquid pipeline, a filtration module, a defoaming module, a desalination module, and an amine salt conversion module; The inlet of the filtration module is connected to the desulfurized amine liquid pipeline, and the outlet is connected to the inlet of the defoaming module and the inlet of the desalination module, respectively; the outlet of the defoaming module is connected to the regenerated amine liquid pipeline and the inlet of the desalination module, respectively; the outlet of the desalination module is connected to the inlet of the amine salt conversion module; the outlet of the amine salt conversion module is connected to the regenerated amine liquid pipeline; the connecting pipelines between the modules can be controlled to be connected or closed; Depending on the specific impurities in the desulfurized amine solution, three schemes are selectively adopted, including: a complete removal scheme, a scheme that removes only heat-stable salt impurities, and a scheme that removes only foaming impurities. Complete removal scheme: The desulfurized amine solution is passed sequentially through the filtration module, defoaming module, desalting module, and amine salt conversion module; A scheme for removing only heat-stable salt impurities involves passing the desulfurized amine solution sequentially through the filtration module, desalination module, and amine salt conversion module. Solution for removing only foaming impurities: The desulfurized amine solution is passed sequentially through the filtration module and the defoaming module; In the complete removal scheme, as each removal cycle is completed, the impurity content in the desulfurized amine solution continuously decreases. The removal of impurities in the desulfurized amine solution involves the following operating parameters: the total volume of desulfurized amine solution in the desulfurization system is represented by Q, the desulfurized amine solution processing capacity is represented by p, and the impurity content is represented by i. Then: The nth cycle of desulfurization amine solution treatment ,unit , n≥2; Impurity content in the desulfurized ammonium solution during the nth cycle Unit: %, n≥2; Total time for impurity removal from desulfurized amine solution up to the nth cycle Unit: h, n≥2; The total volume of desulfurized amine solution processed up to the nth cycle is P, in units of , n≥2; ； In the heat-stable salt removal scheme, the impurity content in the desulfurized amine solution continuously decreases with the completion of each removal cycle. The impurity removal in the desulfurized amine solution involves the following operating parameters: the total desulfurized amine solution volume in the desulfurization system is represented by Q, the desulfurized amine solution processing capacity is represented by p, and the heat-stable salt impurity content is represented by i. Then: The nth cycle of desulfurization amine solution treatment ,unit , n≥2; Impurity content in the desulfurized ammonium solution during the nth cycle Unit: %, n≥2; Total time for impurity removal from desulfurized amine solution up to the nth cycle Unit: h, n≥2; The total volume of desulfurized amine solution processed up to the nth cycle is P, in units of , n≥2; ； In the defoaming impurity removal scheme, the impurity content in the desulfurized amine solution continuously decreases with the completion of each removal cycle. The removal of impurities from the desulfurized amine solution involves the following operating parameters: the total desulfurized amine solution volume in the desulfurization system is represented by Q, the desulfurized amine solution treatment capacity is represented by p, and the foaming impurity content is represented by i. Then: The nth cycle of desulfurization amine solution treatment ,unit , n≥2; Impurity content in the desulfurized amine solution during the nth cycle Unit: %, n≥2; Total time for impurity removal from desulfurized amine solution up to the nth cycle Unit: h, n≥2; The total volume of desulfurized amine solution processed up to the nth cycle is P, in units of , n≥2; 。 2. The method for removing impurities from modular desulfurized amine solution according to claim 1, characterized in that, The defoaming module is equipped with a first regeneration unit; the desalting module is equipped with a second regeneration unit; and the amine salt conversion module is equipped with a third regeneration unit. After each cycle is completed, the impurity removal operation is paused, and the system enters the regeneration mode. According to the regeneration cycle of each module, the defoaming module, desalting module and amine salt conversion module are regenerated through the first regeneration unit, the second regeneration unit and the third regeneration unit, respectively.
3. The method for removing impurities from modular desulfurized amine solution according to claim 2, characterized in that, After each cycle is completed, the desalination module is regenerated. Every 3-4 regenerations of the desalination module, the defoaming module and the amine salt conversion module are regenerated once.
4. The method for removing impurities from modular desulfurized amine solution according to claim 1, characterized in that, When the impurity content in the desulfurized amine solution or the amount of desulfurized amine solution co-treated reaches the required level, the operation of removing impurities from the desulfurized amine solution shall be stopped.
5. The method for removing impurities from modular desulfurized amine solution according to claim 1, characterized in that, A conductivity meter and a pH meter are connected to the outlet of the amine salt conversion module; in the removal method, the conductivity meter and pH meter are used as auxiliary monitoring means.