Corrosion risk evaluation method for recycle hydrogen desulfurization system of hydrogenation device

Abstract

The invention provides a hydrogenation device recycle hydrogen desulfurization system corrosion risk evaluation method, and relates to the field of petroleum refining equipment corrosion evaluation, and the method comprises the following steps: S1, selecting a plurality of key process parameters as evaluation indexes, and establishing a quantitative scoring system; s2, determining the weight of each evaluation index based on the corrosion mechanism of the recycle hydrogen desulfurization system of the hydrogenation device; s3, collecting process parameter data in a preset time period; s4, calculating the score of each evaluation index according to the quantitative scoring system; s5, calculating a total evaluation index score in combination with the weight and the material factor of each evaluation index; and S6, performing corrosion risk assessment and early warning according to the score of the total evaluation index. According to the invention, the operation safety and reliability of the hydrogenation device can be improved, and an important basis can be provided for the optimized operation and preventive maintenance of the device, so that the equipment failure rate is obviously reduced, the service life of the device is prolonged, and the economic benefit and the safety are finally improved.

Description

Technical Field

[0001] This invention relates to the field of corrosion assessment of petroleum refining equipment, and more particularly to a method for assessing the corrosion risk of a circulating hydrogen desulfurization system in a hydrogenation unit. Background Technology

[0002] In modern petroleum refining, hydrotreating is a core technology that plays a crucial role in enhancing crude oil processing depth, improving product quality, and increasing production efficiency. During the hydrotreating reaction, sulfur-containing compounds in the feedstock react with hydrogen to produce hydrocarbons and hydrogen sulfide (H2S). However, the H2S gas produced in this process continuously accumulates in the circulating hydrogen system, not only reducing the partial pressure of hydrogen in the circulating hydrogen, thus hindering the hydrotreating reaction, but also significantly accelerating the corrosion rate of equipment and pipelines, posing a serious threat to the safety and reliability of the entire system.

[0003] To maintain high purity of circulating hydrogen and prevent excessive accumulation of H2S, hydrogenation units are typically equipped with a circulating hydrogen desulfurization system. This system generally uses an alkaline alkanolamine solution as the absorbent, achieving efficient removal of H2S from the circulating hydrogen through a countercurrent absorption process. However, the circulating hydrogen desulfurization system itself faces multiple challenges from H2S, amine solutions, and other corrosive media, posing a potential corrosion risk.

[0004] During the actual operation of a hydrotreating unit, fluctuations in various process parameters, such as the properties of the feedstock oil, the characteristics of the amine solution, and the operating temperature, can significantly impact the corrosion behavior of the circulating hydrodesulfurization system. Therefore, real-time monitoring and systematic statistical analysis of various process parameters are crucial for timely detection of corrosion risks and accurate diagnosis of corrosion causes.

[0005] However, the main challenges currently faced are: first, the variety of process parameters and the sheer volume of data; second, the lack of a clear quantitative correlation between various process parameters and corrosion risk; and third, the existing assessment methods are often too simplistic or subjective, making it difficult to quickly and accurately diagnose potential corrosion risks from massive amounts of process parameter statistics. These factors collectively contribute to the complexity and uncertainty of corrosion risk assessment.

[0006] Furthermore, traditional corrosion monitoring methods, such as corrosion pads and electrochemical probes, while providing valuable data, often suffer from latency, making it difficult to provide real-time early warnings of corrosion risks. Additionally, these methods typically only reflect the corrosion status of localized areas, failing to comprehensively assess the corrosion risk of the entire system.

[0007] Therefore, there is an urgent need to develop a new and systematic method for corrosion risk assessment. Summary of the Invention

[0008] In view of this, this invention proposes a corrosion risk assessment method for a circulating hydrogen desulfurization system in a hydrogenation unit. This method comprehensively considers the influence of various process parameters, establishes a quantitative relationship between process parameters and corrosion risk, and enables rapid and accurate risk diagnosis and early warning based on real-time operating data. This not only helps improve the operational safety and reliability of the hydrogenation unit but also provides an important basis for optimized operation and preventative maintenance, thereby significantly reducing equipment failure rates, extending unit lifespan, and ultimately achieving a dual improvement in economic benefits and safety.

[0009] The technical solution of this invention is implemented as follows:

[0010] This invention provides a method for corrosion risk assessment of a circulating hydrogen desulfurization system in a hydrogenation unit, comprising:

[0011] S1 selects multiple key process parameters as evaluation indicators and establishes a quantitative scoring system;

[0012] S2 determines the weight of each evaluation index based on the corrosion mechanism of the circulating hydrogen desulfurization system of the hydrogenation unit;

[0013] S3 collects process parameter data within a preset time period;

[0014] S4 calculates the scores for each evaluation indicator based on the quantitative scoring system;

[0015] S5 combines the weights of each evaluation indicator with the material factor to calculate the total evaluation indicator score;

[0016] S6 conducts corrosion risk assessment and early warning based on the overall evaluation index score.

[0017] Based on the above scheme, the preferred evaluation indicators include the sulfur content of the feed oil, the acid gas absorption of the amine liquid, the content of thermally stable salts in the amine liquid, the pH value of the amine liquid, and the operating temperature of the desulfurization tower.

[0018] Based on the above scheme, preferably, the quantitative scoring system adopts a percentage system, and corresponding scoring standards are formulated for the evaluation parameters of each evaluation indicator. The scoring standards divide the value range of the evaluation parameters into 6 scoring intervals, each interval corresponding to a score range or score. The score S of each evaluation indicator is calculated based on each score range or score and the calculation formula. j .

[0019] Based on the above scheme, preferably, the evaluation parameter for the sulfur content evaluation index of crude oil is the actual sulfur content value C′. s With sulfur content protection value C s The ratio, based on this evaluation parameter, is used to formulate the following scoring criteria:

[0020] When C′s / C s When <a1, it is the first scoring interval, and the score range of this interval is [b1, b2). The score of the sulfur content of the feedstock oil within this scoring range is k1 = (b2 - b1) / a1;

[0021] When a1≤C′ s / C s When <a2, it is the second scoring interval, and the score range of this interval is [b2, b3). The score of the sulfur content of the feedstock oil within this scoring range is k2 = (b3 - b2) / (a2 - a1);

[0022] When a2≤C′ s / C s When <a3, it is the third scoring interval, and the score range of this interval is [b3, b4). The score of the sulfur content of the feedstock oil within this scoring range is k3 = (b4 - b3) / (a3 - a2);

[0023] When a3≤C′ s / C s When <a4, it is the 4th scoring interval, and the score range of this interval is [b4, b5). The score of the sulfur content of the feedstock oil within this scoring range is k4 = (b5 - b4) / (a4 - a3);

[0024] When a4≤C′ s / C s When <a5, it is the 5th scoring interval, and the score range of this interval is [b5, b6). The score of the sulfur content of the feedstock oil within this scoring range is k5 = (b6 - b5) / (a5 - a4);

[0025] When C′ s / C s When ≥a5, it falls within the 6th scoring interval, and the score for the sulfur content of the feedstock oil within this interval is...

[0026] Among them, a1 <a2<a3<a4<a5,b1> b2>b3>b4>b5>b6, where k1, k2, k3, k4, and k5 are the slope parameters for the sulfur content score of the raw oil.

[0027] Based on the above scheme, preferably, the evaluation parameter for the amine liquid acid gas absorption capacity evaluation index is the actual value of acid gas absorption η. The scoring standard is formulated according to this evaluation parameter as follows:

[0028] When η < c1, it is the first scoring interval, and the score range of this interval is [d1, d2). The score of amine acid gas absorption within this scoring range is... m1 = (d2 - d1) / c1;

[0029] When c1≤η<c2, it is the second scoring interval, and the score range of this interval is [d2, d3). The score of amine acid gas absorption within this scoring range is... m2 = (d3 - d2) / (c2 - c1);

[0030] When c2≤η<c3, it is the third scoring interval, and the score range of this interval is [d3, d4). The score of amine acid gas absorption within this scoring range is... m3 = (d4 - d3) / (c3 - c2);

[0031] When c3≤η<c4, it is the 4th scoring interval, and the score range of this interval is [d4, d5). The score of amine acid gas absorption within this scoring range is... m4 = (d5 - d4) / (c4 - c3);

[0032] When c4≤η<c5, it is the 5th scoring interval, and the score range of this interval is [d5, d6). The score of amine acid gas absorption within this scoring range is... m5 = (d6 - d5) / (c5 - c4);

[0033] When η≥c5, it falls within the 6th scoring interval, and the score for the absorption of amine acid gas within this interval is:

[0034] Where c1 < c2 <c3<c4<c5,d1>d2> d3>d4>d5>d6, m1, m2, m3, m4, and m5 are the slope parameters of the amine liquid acid gas absorption score;

[0035] The scoring range of the amine acid gas absorption evaluation index is determined according to the type of absorbent; that is, different types of absorbents have different values ​​for c1, c2, c3, c4, and c5.

[0036] Based on the above scheme, preferably, the evaluation parameter for the evaluation index of heat-stable salt content in amine solution is the actual value C of heat-stable salt content. h The scoring criteria are formulated based on these evaluation parameters as follows:

[0037] When C h When <e1, it is the first scoring interval, and the score range of this interval is [f1, f2). The score of the thermally stable salt content in the amine solution within this scoring range is z1 = (f2 - f1) / e1;

[0038] When e1≤C hWhen it is less than e2, it is the second scoring interval, and the score range of this interval is [f2, f3). The score of the content of heat-stable salts in the amine solution within this score range is z2 = (f3 - f2) / (e2 - e1);

[0039] When e2 ≤ C h <e3, it is the third scoring interval, and the score range of this interval is [f3, f4). The score of the content of heat-stable salts in the amine solution within this score range is z3 = (f4 - f3) / (e3 - e2);

[0040] When e3 ≤ C h <e4, it is the fourth scoring interval, and the score range of this interval is [f4, f5). The score of the content of heat-stable salts in the amine solution within this score range is z4 = (f5 - f4) / (e4 - e3);

[0041] When e4 ≤ C h <e5, it is the fifth scoring interval, and the score range of this interval is [f5, f6). The score of the content of heat-stable salts in the amine solution within this score range is z5 = (f6 - f5) / (e5 - e4);

[0042] When C h ≥ e5, it is the sixth scoring interval, and the score of the content of heat-stable salts in the amine solution within this interval is

[0043] Among them, e1 < e2 < e3 < e4 < e5, f1 > f2 > f3 > f4 > f5 > f6, and z1, z2, z3, z4, z5 are the slope parameters of the score of the content of heat-stable salts in the amine solution.

[0044] On the basis of the above scheme, preferably, for the evaluation index of the pH value of the amine solution, its evaluation parameter is the actual pH value of the amine solution. The scoring standard is formulated according to this evaluation parameter as follows:

[0045] When pH ≥ g1, it is the first scoring interval, and the score of this interval is

[0046] When g2 ≤ pH < g1, it is the second scoring interval, and the score range of this interval is (h1, h2]. The score of the pH value of the amine solution within this score range is v1 = (h1 - h2) / (g1 - g2);

[0047] When g3 ≤ pH < g2, it is the third scoring interval, and the score range of this interval is (h2, h3]. The score of the pH value of the amine solution within this score range is v2 = (h2 - h3) / (g2 - g3);

[0048] When g4 ≤ pH < g3, it is the 4th scoring interval, and the score range of this interval is (h3, h4], and the score of the amine solution pH within this score range is v3 = (h3 - h4) / (g3 - g4);

[0049] When g5 ≤ pH < g4, it is the 5th scoring interval, and the score range of this interval is (h4, h5], and the score of the amine solution pH within this score range is v4 = (h4 - h5) / (g4 - g5);

[0050] When pH < g5, it is the 6th scoring interval, and the score range of this interval is (h5, h6], and the score of the amine solution pH within this score range is v5 = (h5 - h6) / g5;

[0051] Wherein, g1 > g2 > g3 > g4 > g5, h1 > h2 > h3 > h4 > h5 > h6, and v1, v2, v3, v4, v5 are the slope parameters of the amine solution pH score.

[0052] On the basis of the above solution, preferably, for the evaluation index of the operating temperature of the desulfurization tower, its evaluation parameter is the actual value T of the operating temperature of the desulfurization tower, and the scoring standard is formulated according to this evaluation parameter as follows:

[0053] When T < r1, it is the 1st scoring interval, and the score range of this interval is [w1, w2), and the score of the operating temperature of the desulfurization tower within this score range is u1 = (w2 - w1) / r1;

[0054] When r1 ≤ T < r2, it is the 2nd scoring interval, and the score range of this interval is [w2, w3), and the score of the operating temperature of the desulfurization tower within this score range is u2 = (w3 - w2) / (r2 - r1);

[0055] When r2 ≤ T < r3, it is the 3rd scoring interval, and the score range of this interval is [w3, w4), and the score of the operating temperature of the desulfurization tower within this score range is u3 = (w4 - w3) / (r3 - r2);

[0056] When r3 ≤ T < r4, it is the 4th scoring interval, and the score range of this interval is [w4, w5), and the score of the operating temperature of the desulfurization tower within this score range is u4 = (w5 - w4) / (r4 - r3);

[0057] When r4 ≤ T < r5, it is the 5th scoring interval, and the score range of this interval is [w5, w6), and the score of the operating temperature of the desulfurization tower within this score range is u5 = (w6 - w5) / (r5 - r4);

[0058] When T≥r5, it falls within the 6th scoring interval, and the desulfurization tower operating temperature score within this interval is...

[0059] Among them, r1 <r2<r3<r4<r5,w1>w2>w3>w4> w5 > w6, and u1, u2, u3, u4, and u5 are the slope parameters of the desulfurization tower operating temperature score.

[0060] Based on the above scheme, the preferred formula for calculating the overall evaluation index score is as follows:

[0061] S T =f m ×∑W j S j

[0062] In the formula, S T f is the overall evaluation index score; m W is the material factor. j S represents the weight of the j-th individual evaluation indicator; j denoted as the score of the j-th individual evaluation indicator.

[0063] Based on the above scheme, preferably, the material factor is related to the material of the equipment or pipelines in the circulating hydrogen desulfurization system of the hydrogenation unit, for carbon steel f m =0.9; for low alloy steel f m =1.0; for stainless steel f m =1.2.

[0064] The present invention has the following advantages over the prior art:

[0065] (1) By establishing a quantitative relationship between key process parameters and corrosion risk, the system corrosion risk can be assessed in real time and accurately. This not only enables the timely detection of potential corrosion risks, but also provides an important basis for the optimized operation and preventive maintenance of the unit, thereby significantly improving the operational safety and reliability of the hydrogenation unit, extending the service life of the equipment, and ultimately achieving a dual improvement in economic benefits and safety.

[0066] (2) By identifying key process parameters affecting corrosion in the circulating hydrogen desulfurization system, such as the sulfur content of the feed oil, the acid gas absorption of the amine solution, the content of thermally stable salts in the amine solution, the pH value of the amine solution, and the operating temperature of the desulfurization tower, a comprehensive consideration of factors influencing corrosion risk was achieved. This method overcomes the limitations of traditional single-parameter assessment, improves the comprehensiveness and accuracy of the assessment, and makes the corrosion risk assessment more consistent with actual production conditions. (3) A quantitative scoring system for each key process parameter was established, using a percentage system and dividing the value range of each parameter into multiple scoring intervals. This refined scoring method not only improves the accuracy of the assessment but also reflects the impact of different degrees of parameter deviation on corrosion risk, providing more precise guidance for subsequent risk control and parameter optimization. Attached Figure Description

[0067] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0068] Figure 1 This is a flowchart of the method of the present invention. Detailed Implementation

[0069] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0070] like Figure 1 As shown, this invention provides a corrosion risk assessment method for a circulating hydrogen desulfurization system in a hydrogenation unit, comprising:

[0071] S1 selects multiple key process parameters as evaluation indicators and establishes a quantitative scoring system;

[0072] S2 determines the weight of each evaluation index based on the corrosion mechanism of the circulating hydrogen desulfurization system of the hydrogenation unit;

[0073] S3 collects process parameter data within a preset time period;

[0074] S4 calculates the scores for each evaluation indicator based on the quantitative scoring system;

[0075] S5 combines the weights of each evaluation indicator with the material factor to calculate the total evaluation indicator score;

[0076] S6 conducts corrosion risk assessment and early warning based on the overall evaluation index score.

[0077] Specifically, in one embodiment of the present invention, the key process parameters mainly refer to process operation parameters or analysis and detection data that are highly relevant to the corrosion of the circulating hydrogen desulfurization system of the hydrogenation unit, including but not limited to the sulfur content of the feed oil, the acid gas absorption of the amine liquid, the content of thermally stable salts in the amine liquid, the pH value of the amine liquid, and the operating temperature of the desulfurization tower.

[0078] In this embodiment, the quantitative scoring system adopts a percentage system. Corresponding scoring standards are formulated for the evaluation parameters of each evaluation indicator. The scoring standards divide the value range of the evaluation parameters into six scoring intervals, each interval corresponding to a score range or score. The score S for each evaluation indicator is calculated based on each score range or score and the calculation formula. j .

[0079] In one embodiment, the evaluation parameter for the sulfur content evaluation index of crude oil is the actual sulfur content value C′. s With sulfur content protection value C s The ratio, based on this evaluation parameter, is used to formulate the following scoring criteria:

[0080] When C′ s / C s When <a1, it is the first scoring interval, and the score range of this interval is [b1, b2). The score of the sulfur content of the feedstock oil within this scoring range is k1 = (b2 - b1) / a1;

[0081] When a1≤C′ s / C s When <a2, it is the second scoring interval, and the score range of this interval is [b2, b3). The score of the sulfur content of the feedstock oil within this scoring range is k2 = (b3 - b2) / (a2 - a1);

[0082] When a2≤C′ s / C s When <a3, it is the third scoring interval, and the score range of this interval is [b3, b4). The score of the sulfur content of the feedstock oil within this scoring range is k3 = (b4 - b3) / (a3 - a2);

[0083] When a3≤C′ s / C s When <a4, it is the 4th scoring interval, and the score range of this interval is [b4, b5). The score of the sulfur content of the feedstock oil within this scoring range is k4 = (b5 - b4) / (a4 - a3);

[0084] When a4≤C′ s / C s When <a5, it is the 5th scoring interval, and the score range of this interval is [b5, b6). The score of the sulfur content of the feedstock oil within this scoring range is k5 = (b6 - b5) / (a5 - a4);

[0085] When C′ s / C s When ≥a5, it falls within the 6th scoring interval, and the score for the sulfur content of the feedstock oil within this interval is...

[0086] Among them, a1 <a2<a3<a4<a5,b1>b2> b3>b4>b5>b6, where k1, k2, k3, k4, and k5 are the slope parameters for the sulfur content score of the raw oil.

[0087] Specifically, a1 = 0.80, a2 = 0.95, a3 = 1.00, a4 = 1.05, a5 = 1.10; b1 = 100, b2 = 90, b3 = 80, b4 = 60, b5 = 40, b6 = 0.

[0088] That is, for the evaluation index of sulfur content in crude oil, it is based on the actual value of sulfur content C′. s With sulfur content protection value C s The ratio is used to divide the rating into 6 intervals, as follows:

[0089] C′ s / C s The first scoring interval is <0.80, with a score range of [100, 90). The slope parameter k1 for this scoring interval is calculated as (90-100) / 0.80 = -12.5. Based on the slope parameter, the sulfur content score of the crude oil within this scoring range is calculated. For example, C′ s / C s =0.7, then C′ s / C s =0.6, then C′ s / C s The smaller the value, the higher the score.

[0090] 0.80≤C′ s / C s The second scoring interval is <0.95, with a score range of [90, 80). The slope parameter k2 for this scoring interval is calculated as (80-90) / (0.95-0.80) = -66.67. Based on the slope parameter, the score for the sulfur content of the crude oil within this scoring range is calculated. For example, C′ s / Cs =0.9, then C′ s / C s =0.85, then

[0091] 0.95≤C′ s / C s <1.00 represents the third scoring interval, with a score range of [80, 60). The slope parameter k3 for this interval is calculated as (60-80) / (1.00-0.95) = -400. Based on this slope parameter, the sulfur content score of the crude oil within this scoring range is calculated. For example, C′ s / C s =0.98, then

[0092] 1.00≤C′ s / C s <1.05 is the fourth scoring interval, with a score range of [60, 40). The slope parameter k4 for this scoring interval is calculated as (40-60) / (1.05-1.00) = -400. Based on the slope parameter, the sulfur content score of the crude oil within this scoring range is calculated. For example, C′ s / C s =1.03, then

[0093] 1.05≤C′ s / C s <1.10 represents the 5th scoring interval, with a score range of [40, 0). The slope parameter k5 for this interval is calculated as (0-40) / (1.10-1.05) = -800. Based on this slope parameter, the sulfur content score of the crude oil within this scoring range is calculated. For example, C′ s / C s =1.08, then

[0094] C′ s / C s ≥1.10 is the sixth scoring interval, representing the score for the sulfur content of the feedstock oil.

[0095] In another embodiment, to simplify the scoring system, the scores corresponding to the scoring intervals can be designed as fixed scores, as follows:

[0096] The scoring standard for sulfur content in crude oil is based on the actual value of sulfur content (C). s ') and sulfur content protection value (C s The ratio of ) is used to divide the score into six intervals. C s' / C s <0.80 is the first scoring interval, and the score for the sulfur content of the crude oil is within this interval. 0.80≤C s ' / C s The second scoring range is <0.95, which represents the score for the sulfur content of the crude oil. 0.95≤C s ' / C s <1.00 is the third scoring interval, representing the score for the sulfur content of the crude oil. 1.00≤C s ' / C s <1.05 is the fourth scoring interval, representing the score for the sulfur content of the crude oil. 1.05≤C s ' / C s <1.10 is the fifth scoring interval, representing the score for the sulfur content of the crude oil. C s ' / C s ≥1.10 is the sixth scoring interval, representing the score for the sulfur content of the crude oil.

[0097] In one embodiment, the evaluation parameter for the amine liquid acid gas absorption capacity is the actual value η of the acid gas absorption capacity. Based on this evaluation parameter, the scoring criteria are as follows:

[0098] When η < c1, it is the first scoring interval, and the score range of this interval is [d1, d2). The score of amine acid gas absorption within this scoring range is... m1 = (d2 - d1) / c1;

[0099] When c1≤η<c2, it is the second scoring interval, and the score range of this interval is [d2, d3). The score of amine acid gas absorption within this scoring range is... m2 = (d3 - d2) / (c2 - c1);

[0100] When c2≤η<c3, it is the third scoring interval, and the score range of this interval is [d3, d4). The score of amine acid gas absorption within this scoring range is... m3 = (d4 - d3) / (c3 - c2);

[0101] When c3≤η<c4, it is the 4th scoring interval, and the score range of this interval is [d4, d5). The score of amine acid gas absorption within this scoring range is... m4 = (d5 - d4) / (c4 - c3);

[0102] When c4≤η<c5, it is the 5th scoring interval, and the score range of this interval is [d5, d6). The score of amine acid gas absorption within this scoring range is... m5 = (d6 - d5) / (c5 - c4);

[0103] When η≥c5, it falls within the 6th scoring interval, and the score for the absorption of amine acid gas within this interval is:

[0104] Where c1 < c2 <c3<c4<c5,d1> d2>d3>d4>d5>d6, m1, m2, m3, m4, m5 are slope parameters;

[0105] The scoring range of the amine acid gas absorption evaluation index is determined according to the type of absorbent; that is, different types of absorbents have different values ​​for c1, c2, c3, c4, and c5.

[0106] In this embodiment, the absorbent is N-methyldiethanolamine, ethanolamine, or diethanolamine. Specifically, when the absorbent is N-methyldiethanolamine, c1 = 0.30, c2 = 0.35, c3 = 0.40, c4 = 0.45, and c5 = 0.50; when the absorbent is ethanolamine or diethanolamine, c1 = 0.20, c2 = 0.25, c3 = 0.30, c4 = 0.35, and c5 = 0.40.

[0107] In this embodiment, d1 = 100, d2 = 90, d3 = 80, d4 = 60, d5 = 40, and d6 = 0.

[0108] Based on the set parameter values, the following calculations were performed: When the absorbent is N-methyldiethanolamine, m1 = -33.3, m2 = -200, m3 = -400, m4 = -400, m5 = -800; when the absorbent is ethanolamine or diethanolamine, m1 = -50, m2 = -200, m3 = -400, m4 = -400, m5 = -800. The scores were then calculated using the formulas for each scoring interval, similar to the evaluation of sulfur content in crude oil, and will not be elaborated upon here.

[0109] In another embodiment, the scores corresponding to the scoring intervals can still be designed as fixed values, as follows:

[0110] The scoring criteria for amine liquid acid gas absorption capacity are divided into six scoring intervals based on the type of absorbent and the actual value of acid gas absorption (η). When N-methyldiethanolamine is used as the absorbent, η < 0.30 is the first scoring interval, and the score for amine liquid acid gas absorption capacity in this interval is... The second scoring interval is 0.30 ≤ η < 0.35, and the score for the absorption of amine acid gas is calculated within this interval. The third scoring interval is 0.35 ≤ η < 0.40, and the score for the absorption of amine acid gas is calculated within this interval. 0.40 ≤ η < 0.45 is the 4th scoring range, and the score for the amine solution's hydrogen sulfide absorption volume in this range 0.45 ≤ η < 0.50 is the 5th scoring range, and the score for the amine solution's hydrogen sulfide absorption volume in this range η ≥ 0.50 is the 6th scoring range, and the score for the amine solution's hydrogen sulfide absorption volume in this range When using monoethanolamine or diethanolamine as absorbents, η < 0.20 is the 1st scoring range, and the score for the amine solution's hydrogen sulfide absorption volume in this range 0.20 ≤ η < 0.25 is the 2nd scoring range, and the score for the amine solution's hydrogen sulfide absorption volume in this range 0.25 ≤ η < 0.30 is the 3rd scoring range, and the score for the amine solution's hydrogen sulfide absorption volume in this range 0.30 ≤ η < 0.35 is the 4th scoring range, and the score for the amine solution's hydrogen sulfide absorption volume in this range 0.35 ≤ η < 0.40 is the 5th scoring range, and the score for the amine solution's hydrogen sulfide absorption volume in this range η ≥ 0.40 is the 6th scoring range, and the score for the amine solution's hydrogen sulfide absorption volume in this range

[0111] In one embodiment, for the evaluation index of the content of thermally stable salts in the amine solution, the evaluation parameter is the actual value C of the thermally stable salt content h , and the scoring criteria are formulated according to this evaluation parameter as follows:

[0112] When C h <e1, it is the 1st scoring range, and the score range for this range is [f1, f2), and the score for the content of thermally stable salts in the amine solution within this score range is z1 = (f2 - f1) / e1;

[0113] When e1 ≤ C h <e2, it is the 2nd scoring range, and the score range for this range is [f2, f3), and the score for the content of thermally stable salts in the amine solution within this score range is z2 = (f3 - f2) / (e2 - e1);

[0114] When e2 ≤ C h <e3, it is the 3rd scoring range, and the score range for this range is [f3, f4), and the score for the content of thermally stable salts in the amine solution within this score range is z3 = (f4 - f3) / (e3 - e2);

[0115] When e3 ≤ C h <e4, it is the 4th scoring range, and the score range for this range is [f4, f5), and the score for the content of thermally stable salts in the amine solution within this score range is z4 = (f5 - f4) / (e4 - e3);

[0116] When e4 ≤ C h < e5, it is the 5th scoring interval, and the score range of this interval is [f5, f6), and the score of the content of heat-stable salts in the amine solution within this score range is z5 = (f6 - f5) / (e5 - e4);

[0117] When C h ≥ e5, it is the 6th scoring interval, and the score of the content of heat-stable salts in the amine solution within this interval is

[0118] Among them, e1 < e2 < e3 < e4 < e5, f1 > f2 > f3 > f4 > f5 > f6, and z1, z2, z3, z4, z5 are slope parameters.

[0119] Specifically, e1 = 0.5%, e2 = 1.0%, e3 = 2.0%, e4 = 2.5%, e5 = 3.0%; f1 = 100, f2 = 90, f3 = 80, f4 = 60, f5 = 40, f6 = 0. At this time, for the convenience of calculation, the unit is not considered, and numerically calculated, z1 = -20, z2 = -20, z3 = -20, z4 = -40, z5 = -80. Then, the scores are calculated according to the respective score calculation formulas of the scoring intervals, and the specific method is similar to the evaluation index of the sulfur content of the feedstock oil, which will not be elaborated here.

[0120] In another embodiment, the scores of each scoring interval are designed as fixed scores, specifically as follows:

[0121] The scoring standard for the content of heat-stable salts in the amine solution divides six scoring intervals according to the actual value of the content of heat-stable salts (C h ). C h < O.5% is the 1st scoring interval, and the score of the content of heat-stable salts in the amine solution in this interval ≤ C h < 1.0% is the 2nd scoring interval, and the score of the content of heat-stable salts in the amine solution in this interval 1.0% ≤ C h < 2.0% is the 3rd scoring interval, and the score of the content of heat-stable salts in the amine solution in this interval 2.0% ≤ C h < 2.5% is the 4th scoring interval, and the score of the content of heat-stable salts in the amine solution in this interval 2.5% ≤ C h < 3.0% is the 5th scoring interval, and the score of the content of heat-stable salts in the amine solution in this interval C h ≥ 3.0% is the 6th scoring interval, and the score of the content of heat-stable salts in the amine solution in this interval

[0122] In one embodiment, for the evaluation index of the pH value of amine solution, the evaluation parameter is the actual pH value of the amine solution. The scoring criteria are formulated based on this evaluation parameter as follows:

[0123] When pH ≥ g1, it is the first scoring interval, and the score for this interval is

[0124] When g2 ≤ pH < g1, it is the second scoring interval, and the score range for this interval is (h1, h2], and the score of the amine solution pH within this score range is v1 = (h1 - h2) / (g1 - g2);

[0125] When g3 ≤ pH < g2, it is the third scoring interval, and the score range for this interval is (h2, h3], and the score of the amine solution pH within this score range is v2 = (h2 - h3) / (g2 - g3);

[0126] When g4 ≤ pH < g3, it is the fourth scoring interval, and the score range for this interval is (h3, h4], and the score of the amine solution pH within this score range is v3 = (h3 - h4) / (g3 - g4);

[0127] When g5 ≤ pH < g4, it is the fifth scoring interval, and the score range for this interval is (h4, h5], and the score of the amine solution pH within this score range is v4 = (h4 - h5) / (g4 - g5);

[0128] When pH < g5, it is the sixth scoring interval, and the score range for this interval is (h5, h6], and the score of the amine solution pH within this score range is v5 = (h5 - h6) / g5;

[0129] Among them, g1 > g2 > g3 > g4 > g5, h1 > h2 > h3 > h4 > h5 > h6, and v1, v2, v3, v4, v5 are the slope parameters of the amine solution pH score.

[0130] Specifically, g1 = 11.0, g2 = 10.5, g3 = 10.0, g4 = 9.5, g5 = 9.0; h1 = 100, h2 = 90, h3 = 80, h4 = 60, h5 = 40, h6 = 0. It is calculated that v1 = 20, v2 = 20, v3 = 40, v4 = 40, v5 = 4.44. Then, the scores are calculated according to the calculation formulas of each score range. It should be noted that the higher the pH value of the amine solution, the higher the score. The specific calculation process is similar to the evaluation index of the sulfur content of the feedstock oil and will not be elaborated here.

[0131] In another embodiment, the scores of each scoring interval are designed as fixed scores, specifically as follows:

[0132] The amine solution pH scoring standard divides six scoring intervals according to the actual value of the amine solution pH. When pH ≥ 11.0, it is the 1st scoring interval, and the score of the amine solution pH in this interval is When 10.5 ≤ pH < 11.0, it is the 2nd scoring interval, and the score of the amine solution pH in this interval is When 10.0 ≤ pH < 10.5, it is the 3rd scoring interval, and the score of the amine solution pH in this interval is When 9.5 ≤ pH < 10.0, it is the 4th scoring interval, and the score of the amine solution pH in this interval is When 9.0 ≤ pH < 9.5, it is the 5th scoring interval, and the score of the amine solution pH in this interval is When pH < 9.0, it is the 6th scoring interval, and the score of the amine solution pH in this interval is

[0133] In one embodiment, for the evaluation index of the operating temperature of the desulfurization tower, its evaluation parameter is the actual value T of the operating temperature of the desulfurization tower. The scoring standard is formulated according to this evaluation parameter as follows:

[0134] When T < r1, it is the first scoring interval, and the score range of this interval is [w1, w2). The score of the operating temperature of the desulfurization tower within this score range is u1 = (w2 - w1) / r1;

[0135] When r1 ≤ T < r2, it is the second scoring interval, and the score range of this interval is [w2, w3). The score of the operating temperature of the desulfurization tower within this score range is u2 = (w3 - w2) / (r2 - r1);

[0136] When r2 ≤ T < r3, it is the third scoring interval, and the score range of this interval is [w3, w4). The score of the operating temperature of the desulfurization tower within this score range is u3 = (w4 - w3) / (r3 - r2);

[0137] When r3 ≤ T < r4, it is the fourth scoring interval, and the score range of this interval is [w4, w5). The score of the operating temperature of the desulfurization tower within this score range is u4 = (w5 - w4) / (r4 - r3);

[0138] When r4 ≤ T < r5, it is the fifth scoring interval, and the score range of this interval is [w5, w6). The score of the operating temperature of the desulfurization tower within this score range is u5 = (w6 - w5) / (r5 - r4);

[0139] When T ≥ r5, it is the sixth scoring interval, and the score of the operating temperature of the desulfurization tower within this interval is

[0140] Among them, r1 <r2<r3<r4<r5,w1>w2>w3>w4> w5 > w6, and u1, u2, u3, u4, and u5 are slope parameters.

[0141] Specifically, r1 = 50℃, r2 = 55℃, r3 = 60℃, r4 = 65℃, r5 = 70℃; w1 = 100, w2 = 90, w3 = 80, w4 = 60, w5 = 40, w6 = 0. The calculated values ​​are u1 = -0.2, u2 = -2, u3 = -4, u4 = -4, u5 = -8. The scores are then calculated using the formulas for each score range. The specific calculation process is similar to that for the evaluation of sulfur content in raw oil, and will not be elaborated here.

[0142] In another embodiment, the scores for each scoring interval are designed to be fixed scores, as follows:

[0143] The desulfurization tower operating temperature scoring standard is divided into six scoring intervals based on the actual operating temperature (T) of the desulfurization tower. T < 50℃ is the first scoring interval, and the desulfurization tower operating temperature score in this interval is... The second scoring interval is 50℃≤T<55℃, and the desulfurization tower operating temperature score is based on this interval. The third scoring interval is 55℃≤T<60℃, and the desulfurization tower operating temperature score is based on this interval. The fourth scoring range is 60℃≤T<65℃, and the desulfurization tower operating temperature score is based on this range. The fifth scoring range is 65℃≤T<70℃, and the desulfurization tower operating temperature score is based on this range. The sixth scoring interval is T≥70℃, and the desulfurization tower operating temperature score is based on this interval.

[0144] In one embodiment of the present invention, process parameter data within a preset time period is collected. This data can be real-time monitored process parameter data, process parameter data at a specific time, or historical process parameter data for a specific time period. After collecting the process parameter data, the scores for each scoring interval of the five evaluation indicators are calculated according to the aforementioned quantitative scoring system. Then, the total score for each individual evaluation indicator is calculated. The present invention does not specifically limit the calculation method for the total score of each individual evaluation indicator, and there are multiple implementation methods:

[0145]

[0146] In the formula, S j This represents the total score for a single evaluation indicator. ω represents the score within the i-th scoring interval, n represents the number of times the single evaluation indicator is collected within the preset time period, and ω represents the score within the i-th scoring interval. i It can represent the number of times the score of this single evaluation indicator is in the i-th interval within a preset time period.

[0147] If the process parameter data is historical process parameter data for a certain period of time, the time-weighted average method can be used to calculate the total score of a single evaluation indicator, for example:

[0148]

[0149] In the formula, T i T represents the cumulative time during which the process parameters fall within the i-th scoring interval within a preset time period. total This refers to the total time span of historical process parameter data.

[0150] Specifically, the overall evaluation index score is calculated based on the total score of each individual evaluation index, the weight of each individual evaluation index, and the material factor, as shown in the following formula:

[0151] S T =f m ×ΣW j S j (j = s, a, h, pH, t)

[0152] S T The overall evaluation index score; f m W is the material factor. j S represents the weight of a single evaluation indicator. j This represents the total score for a single evaluation indicator.

[0153] In this embodiment, the weight of each evaluation index is assessed based on the impact of fluctuations in key process parameters during the unit's production on the circulating hydrogen desulfurization system of the hydrogenation unit. Among these, the weight of the feedstock oil sulfur content is W. s =0.15; Weight W for amine acid gas absorption a =0.40; Weight W of heat-stable salt content in amine solution h =0.3; pH weight of amine solution W pH =0.05; Desulfurization tower operating temperature weight W t =0.1. The material factor is related to the material of the equipment or pipelines in the circulating hydrogen desulfurization system of the hydrogenation unit. For carbon steel f m =0.9; for low alloy steel f m =1.0; for stainless steel f m =1.2.

[0154] In this embodiment, corrosion risk assessment and early warning are based on the overall evaluation index score or the total score of individual evaluation indicators. Early warning values ​​and risk ratings can be set based on expert evaluation and the company's risk tolerance. For example, assessment and early warning can be based on the overall evaluation index score: when S... T When the risk level is above 80, no warning is needed; when it is above 70... T When the risk level is ≤80, it is considered medium risk, and a Level 1 warning is issued; when the risk level is ≤60, it is considered medium risk. T ​​When the risk level is ≤70, it is considered medium to high risk, and a level-two warning is issued; when the risk level T A score ≤60 indicates high risk, triggering a Level 3 warning. Assessment and warning are based on the total score of each individual evaluation indicator: when S... j >80 indicates low risk, no warning required; when 70... j When the value is ≤80, it is considered medium risk, and a Level 1 warning is issued for the single evaluation indicator; when it is 60... j When S ≤ 70, it is considered medium to high risk, with a level-two warning for the single evaluation indicator; when S j When the value is ≤60, it indicates high risk, and a Level 3 warning is issued for the single evaluation indicator.

[0155] Example 1

[0156] This invention provides a specific embodiment to illustrate a simplified calculation method:

[0157] In the first quarter, a total of 90 data points were collected for the process parameters of a certain residue oil hydrotreating unit, including feedstock sulfur content, 20 data points for amine acid gas absorption, 12 data points for thermally stable salt content in amine solution, 12 data points for amine solution pH value, and 90 data points for desulfurization tower operating temperature. The collected data were statistically analyzed based on the quantitative scoring system and scoring criteria established in this method. The distribution of scoring intervals for each process parameter statistical data is shown in the table below.

[0158]

[0159] The total score for each individual evaluation indicator is calculated based on the statistical data.

[0160] Total score for sulfur content in crude oil:

[0161]

[0162] Total score for amine acid gas absorption:

[0163]

[0164] Total score for heat-stable salt content in amine solution:

[0165]

[0166] Total pH score of amine solution:

[0167]

[0168] Total score for desulfurization tower operating temperature:

[0169]

[0170] The circulating hydrogen desulfurization system of this device is made of Q345R, a low-alloy steel. m =1.0, and the total evaluation index score is calculated by combining the weights of each individual evaluation index:​​

[0171] S T =1.0×(0.15×78.56+0.4×64.50+0.3×82.50+0.05×81.67+0.1×80.78)=74.49

[0172] Based on the set warning values ​​and risk ratings, the overall evaluation score of the circulating hydrogen desulfurization system of this unit is 74.49, which is considered medium risk, and a Level 1 warning is issued. The total scores for the thermally stable salt content in the amine liquid, the pH value of the amine liquid, and the operating temperature of the desulfurization tower are 82.50, 81.67, and 80.78, respectively, which are considered low risk, and no warning is issued. The total score for the sulfur content in the feed oil is 78.56, which is considered medium risk, and a Level 1 warning is issued for the sulfur content in the feed oil. The total score for the acid gas absorption of the amine liquid is 64.50, which is considered medium to high risk, and a Level 2 warning is issued for the acid gas absorption of the amine liquid.

[0173] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for assessing the corrosion risk of a circulating hydrogen desulfurization system in a hydrogenation unit, characterized in that, include: S1 selects multiple key process parameters as evaluation indicators and establishes a quantitative scoring system; S2 determines the weight of each evaluation index based on the corrosion mechanism of the circulating hydrogen desulfurization system of the hydrogenation unit; S3 collects process parameter data within a preset time period; S4 calculates the scores for each evaluation indicator based on the quantitative scoring system; S5 combines the weights of each evaluation indicator with the material factor to calculate the total evaluation indicator score; S6 conducts corrosion risk assessment and early warning based on the overall evaluation index score.

2. The corrosion risk assessment method for a circulating hydrogen desulfurization system in a hydrogenation unit as described in claim 1, characterized in that, Evaluation indicators include the sulfur content of the feed oil, the amount of acid gas absorbed by the amine solution, the content of thermally stable salts in the amine solution, the pH value of the amine solution, and the operating temperature of the desulfurization tower.

3. The corrosion risk assessment method for a circulating hydrogen desulfurization system in a hydrogenation unit as described in claim 2, characterized in that, The quantitative scoring system adopts a 100-point scale, and corresponding scoring standards are formulated for the evaluation parameters of each evaluation indicator. The scoring standards divide the value range of the evaluation parameters into six scoring intervals, each corresponding to a score range or score. The score S for each evaluation indicator is calculated based on each score range or score and the calculation formula. j .

4. The corrosion risk assessment method for a circulating hydrogen desulfurization system in a hydrogenation unit as described in claim 3, characterized in that, For the evaluation index of sulfur content in crude oil, the evaluation parameter is the actual value of sulfur content C′. s With sulfur content protection value C s The ratio, based on this evaluation parameter, is used to formulate the following scoring criteria: When C′ s / C s When <a1, it is the first scoring interval, and the score range of this interval is [b1, b2). The score of the sulfur content of the feedstock oil within this scoring range is k1 = (b2 - b1) / a1; When a1≤C′ s / C s When <a2, it is the second scoring interval, and the score range of this interval is [b2, b3). The score of the sulfur content of the feedstock oil within this scoring range is k2 = (b3 - b2) / (a2 - a1); When a2≤C′ s / C s When <a3, it is the third scoring interval, and the score range of this interval is [b3, b4). The score of the sulfur content of the feedstock oil within this scoring range is k3 = (b4 - b3) / (a3 - a2); When a3≤C′ s / C s When <a4, it is the 4th scoring interval, and the score range of this interval is [b4, b5). The score of the sulfur content of the feedstock oil within this scoring range is k4 = (b5 - b4) / (a4 - a3); When a4≤C′ s / C s When <a5, it is the 5th scoring interval, and the score range of this interval is [b5, b6). The score of the sulfur content of the feedstock oil within this scoring range is k5 = (b6 - b5) / (a5 - a4); When C′ s / C s When ≥a5, it falls within the 6th scoring interval, and the score for the sulfur content of the feedstock oil within this interval is... Among them, a1 <a2<a3<a4<a5,b1> b2>b3>b4>b5>b6, where k1, k2, k3, k4, and k5 are the slope parameters for the sulfur content score of the raw oil.

5. The corrosion risk assessment method for a circulating hydrogen desulfurization system in a hydrogenation unit as described in claim 3, characterized in that, For the evaluation index of amine liquid acid gas absorption, the evaluation parameter is the actual value of acid gas absorption, η. The scoring standard is formulated based on this evaluation parameter as follows: When η < c1, it is the first scoring interval, and the score range of this interval is [d1, d2). The score of amine acid gas absorption within this scoring range is... m1 = (d2 - d1) / c1; When c1≤η<c2, it is the second scoring interval, and the score range of this interval is [d2, d3). The score of amine acid gas absorption within this scoring range is... m2 = (d3 - d2) / (c2 - c1); When c2≤η<c3, it is the third scoring interval, and the score range of this interval is [d3, d4). The score of amine acid gas absorption within this scoring range is... m3 = (d4 - d3) / (c3 - c2); When c3≤η<c4, it is the 4th scoring interval, and the score range of this interval is [d4, d5). The score of amine acid gas absorption within this scoring range is... m4 = (d5 - d4) / (c4 - c3); When c4≤η<c5, it is the 5th scoring interval, and the score range of this interval is [d5, d6). The score of amine acid gas absorption within this scoring range is... m5 = (d6 - d5) / (c5 - c4); When η≥c5, it falls within the 6th scoring interval, and the score for the absorption of amine acid gas within this interval is: Among them, c1 <c2<c3<c4<c5,d1>d2> d3>d4>d5>d6, m1, m2, m3, m4, and m5 are the slope parameters of the amine liquid acid gas absorption score; The scoring range of the amine acid gas absorption evaluation index is determined according to the type of absorbent; that is, different types of absorbents have different values ​​for c1, c2, c3, c4, and c5.

6. The corrosion risk assessment method for a circulating hydrogen desulfurization system in a hydrogenation unit as described in claim 3, characterized in that, For the evaluation index of heat-stable salt content in amine solution, the evaluation parameter is the actual value C of the heat-stable salt content. h The scoring criteria are formulated based on these evaluation parameters as follows: When C h <is less than e1, it is the first scoring interval, and the score range of this interval is [f1, f2). The score of the content of heat-stable salts in the amine solution within this score range is z1 = (f2 - f1) / e1; When e1 ≤ C h <When e2, it is the second scoring interval, and the score range of this interval is [f2, f3). The score of the content of heat stable salts in the amine solution within this score range is z2 = (f3 - f2) / (e2 - e1); When e2≤C h When <e3, it is the third scoring interval, and the score range of this interval is [f3, f4). The score of the thermally stable salt content in the amine solution within this scoring range is z3 = (f4 - f3) / (e3 - e2); When e3≤C h When <e4, it is the 4th scoring interval, and the score range of this interval is [f4, f5). The score of the thermally stable salt content in the amine solution within this scoring range is z4 = (f5 - f4) / (e4 - e3); When e4 ≤ C h <and e5, it is the 5th scoring interval, and the score range of this interval is [f5, f6), and the score of the content of heat-stable salts in the amine solution within this score range is z5 = (f6 - f5) / (e5 - e4); When C h When e5 is ≥, it falls within the 6th scoring interval, where the score for the thermally stable salt content in the amine solution is... Among them, e1 <e2<e3<e4<e5,f1> f2>f3>f4>f5>f6, z1, z2, z3, z4, and z5 are the slope parameters of the scores for the thermally stable salt content in the amine solution.

7. The corrosion risk assessment method for a circulating hydrogen desulfurization system in a hydrogenation unit as described in claim 3, characterized in that, For the evaluation index of amine solution pH value, the evaluation parameter is the actual pH value of the amine solution, and the scoring criteria are formulated based on this evaluation parameter as follows: When pH ≥ g1, it falls within the first scoring interval, and the score for this interval is... When g2 ≤ pH < g1, it is the second scoring interval, and the score range of this interval is (h1, h2]. Within this scoring range, the pH score of the amine solution is... v1 = (h1 - h2) / (g1 - g2); When g3 ≤ pH < g2, it falls within the third scoring interval, with a score range of (h2, h3). Within this interval, the pH score of the amine solution is... v2 = (h2 - h3) / (g2 - g3); When g4 ≤ pH < g3, it is the 4th scoring interval, and the score range of this interval is (h3, h4]. Within this scoring range, the pH score of the amine solution is... v3 = (h3 - h4) / (g3 - g4); When g5 ≤ pH < g4, it is the 5th scoring interval, and the score range of this interval is (h4, h5]. Within this scoring range, the pH score of the amine solution is... v4 = (h4 - h5) / (g4 - g5); When pH < g5, it falls within the 6th scoring interval, with a score range of (h5, h6). Within this range, the pH score of the amine solution is... v5 = (h5 - h6) / g5; Where g1>g2>g3>g4>g5, h1>h2>h3>h4>h5>h6, and v1, v2, v3, v4, and v5 are the slope parameters of the pH score of the amine solution.

8. The corrosion risk assessment method for a circulating hydrogen desulfurization system in a hydrogenation unit as described in claim 3, characterized in that, The evaluation parameter for the desulfurization tower operating temperature is the actual operating temperature T of the desulfurization tower. The scoring criteria based on this parameter are as follows: When T < r1, it is the first scoring interval, and the score range of this interval is [w1, w2). The score of the desulfurization tower operating temperature within this score range is u1 = (w2 - w1) / r1; When r1 ≤ T < r2, it is the second scoring interval, and the score range of this interval is [w2, w3). The score of the desulfurization tower operating temperature within this score range is u2 = (w3 - w2) / (r2 - r1); When r2 ≤ T < r3, it is the third scoring interval, and the score range of this interval is [w3, w4). The score of the operating temperature of the desulfurization tower within this score range is u3 = (w4 - w3) / (r3 - r2); When r3 ≤ T < r4, it is the fourth scoring interval, and the score range of this interval is [w4, w5). The score of the desulfurization tower operating temperature within this score range is u4 = (w5 - w4) / (r4 - r3); When r4 ≤ T < r5, it is the 5th scoring interval, and the score range of this interval is [w5, w6). The score of the operating temperature of the desulfurization tower within this score range is u5 = (w6 - w5) / (r5 - r4); When T≥r5, it falls within the 6th scoring interval, and the desulfurization tower operating temperature score within this interval is... Among them, r1 <r2<r3<r4<r5,w1>w2>w3>w4> w5 > w6, and u1, u2, u3, u4, and u5 are the slope parameters of the desulfurization tower operating temperature score.

9. The corrosion risk assessment method for a circulating hydrogen desulfurization system in a hydrogenation unit as described in claim 3, characterized in that, The formula for calculating the overall evaluation index score is as follows: S T =f m ×∑W j S j In the formula, S T The overall evaluation index score; f m W is the material factor. j S represents the weight of the j-th individual evaluation indicator; j denoted as the score of the j-th individual evaluation indicator.

10. The corrosion risk assessment method for a circulating hydrogen desulfurization system in a hydrogenation unit as described in claim 9, characterized in that, Material factors are related to the material of the equipment or pipelines in the circulating hydrogen desulfurization system of the hydrogenation unit. For carbon steel f m =0.9; for low alloy steel f m =1.0; for stainless steel f m =1.2.

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