CN-121988145-A - Dehydration control method for acid gas

Abstract

The invention provides a dehydration control method of acid gas. The method comprises the steps of determining the composition of the acid gas, simulating a saturated water content change curve of a combination of CO 2 and different impurity gas components at set content, determining the combination of the components with the greatest influence as an acid gas dehydration experiment component, determining saturated water contents of the combination of CO 2 and the acid gas dehydration experiment component at different temperatures and different pressures, obtaining a saturated water content change curve of the combination of CO 2 and the acid gas dehydration experiment component based on the saturated water contents, fitting the lowest point of each curve in the saturated water content change curve to obtain a saturated water content model of the acid gas, and substituting the temperature and the pressure of the acid gas with the saturated water content to be determined into the model to obtain the corresponding saturated water content of the acid gas at the temperature and the pressure. The method can conveniently and accurately determine the saturated water content of the acid gas at a certain temperature and pressure.

Inventors

• Chen Siding
• ZENG LUXUAN
• ZHANG ZHE
• HUANG JIAN
• WANG CHUNYAN

Assignees

• 中国石油天然气股份有限公司

Dates

Publication Date

20260508

Application Date

20241104

Claims (16)

1. 1. A method for controlling dehydration of acid gas, comprising the steps of: Determining the composition of acid gas, wherein the acid gas contains CO 2 and impurity gas components, simulating a saturated water content change curve of the combination of CO 2 and different impurity gas components in the acid gas at a set content, and determining the combination of the components with the greatest influence on the saturated water content change curve as an acid gas dehydration experimental component; step 2, taking the acid gas dehydration experimental component as an object, and determining the saturated water content of the combination of the CO 2 and the acid gas dehydration experimental component at different temperatures and different pressures; step 3, obtaining a saturated water content change curve chart of the combination of the CO 2 and the acid gas dehydration experimental component based on the saturated water content obtained in the step 2; step 4, fitting to obtain a saturated water content model of the acid gas based on the lowest point of each curve in the saturated water content change curve graph; and 5, substituting the temperature and the pressure of the acid gas with the saturation water content to be determined into a saturation water content model of the acid gas to obtain the corresponding saturation water content of the acid gas at the temperature and the pressure.
2. 2. The method for controlling dehydration of an acid gas according to claim 1, wherein in step 1, the impurity gas component is selected from one or a combination of two or more of N 2 、Ar、H 2 、CH 4 、O 2 、H 2 S.
3. 3. The dehydration control method for an acid gas according to claim 1 or 2, wherein a CO 2 content in the acid gas is 90 to 99.8% by volume; At the same time, the composition of the acid gas also satisfies one or a combination of more than two of the following requirements: The content of N 2 is less than or equal to 7v%, the content of Ar is 0.01v% to 4v%, the content of H 2 is less than or equal to 4v%, the content of CH 4 is 0.01v% to 4v%, the content of O 2 is 0.001v% to 4v%, and the content of H 2 S is 0.002v% to 1.3v%.
4. 4. The method for controlling dehydration of acid gas according to claim 1, wherein in step 1, the process of simulating the saturated water content variation curve of the combination of CO 2 and different impurity gas components in acid gas at a set content specifically comprises: Obtaining saturated water content values of the combination of CO 2 and certain impurity gas components under the set content, the set temperature and different pressures; Normalizing the saturated water content value to obtain a saturated water content change curve of the combination of the CO 2 and the impurity gas component at the set content and the set temperature; And repeating the process to obtain a saturated water content change curve of the combination of the CO 2 and each impurity gas component at the set content and the set temperature, thereby obtaining a saturated water content change curve corresponding to different impurity gas components in the simulated acid gas.
5. 5. The method for controlling dehydration of an acid gas according to claim 1 or 4, wherein in step 1, the combination of components having the greatest influence on the saturated water content change curve contains 2 or more impurity gas components.
6. 6. The method according to claim 1 or 5, wherein in step 1, the saturated water content change curve is a saturated water content versus pressure curve.
7. 7. The method for controlling dehydration of an acid gas according to claim 1, wherein in step 2, the process of determining the saturated water content of the combination of CO 2 and the acid gas dehydration experimental component at different temperatures and different pressures comprises: step 21, obtaining saturated water content of the combination of CO 2 and the acid gas dehydration experimental component at a certain temperature and a certain pressure; Step 22, changing the temperature and the pressure, and repeating the step 21 until the saturated water content of the combination of the CO 2 and the acid gas dehydration experimental component is obtained at a plurality of temperatures in a preset temperature range and a plurality of pressures in a preset pressure range.
8. 8. The method for controlling the dehydration of an acid gas according to claim 7, wherein said predetermined temperature range is-10 ℃ to 20 ℃.
9. 9. The method for controlling dehydration of an acid gas according to claim 7 or 8, wherein the change value upon changing the temperature is 2.0 ℃ to 3.0 ℃.
10. 10. The method for controlling dehydration of acid gas according to claim 7, wherein said predetermined pressure is in the range of 0.1MPa to 20MPa.
11. 11. The method for controlling dehydration of an acid gas according to claim 7 or 10, wherein the variation value when the pressure is changed is 0.1MPa to 3.0MPa.
12. 12. The method for controlling the dehydration of an acid gas according to claim 1, wherein in step 3, the graph of the saturated water content of the acid gas dehydration test component contains a graph of the saturated water content of the acid gas dehydration test component at different temperatures with pressure.
13. 13. The method for controlling the dehydration of an acid gas according to claim 1, wherein in step 3, the process of obtaining a saturated water content variation graph of the combination of CO 2 and the acid gas dehydration experimental component based on the saturated water content obtained in step 2 comprises: Normalizing the saturated water content values of the combination of the CO 2 and the acid gas dehydration experimental component at a certain temperature and different pressures to obtain a saturated water content change curve of the combination of the CO 2 and the acid gas dehydration experimental component at the temperature; Repeating the above process to obtain a saturated water content change curve of the combination of the CO 2 and the acid gas dehydration experimental component at different temperatures within a preset temperature range; and placing all saturated water content change curves in the same coordinate system to obtain a saturated water content change curve chart of the combination of the CO 2 and the acid gas dehydration experimental component.
14. 14. The method for controlling dehydration of an acid gas according to claim 1, wherein in step 4, R 2 of the saturated water content model of the acid gas is required to be 95% or more.
15. 15. The acid gas dehydration control method according to claim 1, wherein the acid gas dehydration control method further comprises the steps of: And (3) dehydrating the acid gas according to the saturated water content of the acid gas obtained in the step (5) at the temperature and the pressure.
16. 16. The method for controlling dehydration of an acid gas according to claim 15, wherein said dehydration treatment is dehydration to a water content of 200ppm or less.

Description

Dehydration control method for acid gas Technical Field The invention relates to a dehydration control method of acid gas, and belongs to the technical field of gas dehydration control. Background Carbon Capture and Sequestration (CCS), and carbon capture, utilization and sequestration (CCUS) technologies have become a focus of attention. These techniques are significant in reducing greenhouse gas emissions and driving energy conversion. However, both the product gas (high purity CO 2 containing impurities) of the carbon capture unit in CCS/CCUS systems and the feed gas (H 2 S and CO 2) of the acid gas reinjection system are typical acid gases, which under water containing conditions can form corrosive acid or hydrates, which pose a serious threat to critical equipment in oil and gas extraction and handling, leading to equipment corrosion, plugging, and thus affecting the stability and safety of the overall process system. The traditional acid gas dehydration method mainly comprises a molecular sieve solid adsorption method and a triethylene glycol solvent absorption method, the two methods are based on the principle of physical adsorption or chemical absorption to realize effective removal of moisture in the acid gas, the industrial requirement is met to a certain extent, and certain limitations exist in some cases. Therefore, it is desirable to devise an optimal dehydration control method for acid gas that combines temperature and pressure and considers the parameters of the acid gas phase. Disclosure of Invention In order to solve the technical problems, the invention aims to provide a dehydration control method for acid gas, which combines temperature and pressure and comprehensively considers the phase parameters of the acid gas, can conveniently and accurately determine the saturated water content of the acid gas, and further determine the dehydration treatment degree. In order to achieve the above object, the present invention provides a dehydration control method for acid gas, comprising the steps of: Determining the composition of acid gas, wherein the acid gas contains CO 2 and impurity gas components, simulating a saturated water content change curve of the combination of CO 2 and different impurity gas components in the acid gas at a set content, and determining the combination of the components with the greatest influence on the saturated water content change curve as an acid gas dehydration experimental component; step 2, taking the acid gas dehydration experimental component as an object, and determining the saturated water content of the combination of the CO 2 and the acid gas dehydration experimental component at different temperatures and different pressures; Step 3, obtaining a saturated water content change curve chart of the acid gas dehydration experimental component based on the saturated water content obtained in the step 2; step 4, fitting to obtain a saturated water content model of the acid gas based on the lowest point of each curve in the saturated water content change curve graph; and 5, substituting the temperature and the pressure of the acid gas with the saturation water content to be determined into a saturation water content model of the acid gas to obtain the corresponding saturation water content of the acid gas at the temperature and the pressure. According to a specific embodiment of the present invention, preferably, in step 1, the process of determining the composition of the acid gas (i.e. the component composition and component content of the acid gas) is performed by gas composition analysis (e.g. gas chromatography) or is determined according to prior art data. According to the embodiment of the present invention, preferably, the acid gas in the step 1 is the acid gas involved in "carbon capture and sequestration" (CCS) and "carbon capture, utilization and sequestration" (CCUS), and the acid gas is mainly composed of CO 2 and contains several other impurity gases. More preferably, in step 1, the impurity gas component is selected from one or a combination of two or more of N 2、Ar、H2、CH4、O2、H2 S. According to a specific embodiment of the present invention, preferably, in step 1, the CO 2 content is 90v% to 99.8v% based on 100v% of the total content of the components of the acid gas (v% represents volume percentage, the same applies hereinafter); meanwhile, the impurity gas component content in the acid gas also satisfies one or a combination of more than two of the following requirements: The content of N 2 is less than or equal to 7v%, the content of Ar is 0.01v% to 4v%, the content of H 2 is less than or equal to 4v%, the content of CH 4 is 0.01v% to 4v%, the content of O 2 is 0.001v% to 4v%, and the content of H 2 S is 0.002v% to 1.3v%. According to a specific embodiment of the present invention, preferably, in step 1, the process of simulating the saturated water content variation curve of the combination of CO 2 and different impurity gas components in the a