A method for detecting properties of mixed crude oil fractions with component tracking

Abstract

The present invention discloses a method for detecting the properties of mixed crude oil fractions with component tracking. This method addresses the problem of a large number of combinations and the potential for multiple combined solutions in crude oil property detection methods based on optimized solutions using near-infrared spectra of mixed crude oil and its component crudes. By using component tracking technology, the method optimizes the process of determining the types and proportions of the component crudes in the mixed crude oil. Compared to existing methods, this method effectively reduces the number of component crude oil types to be determined, determines the initial proportions of the component crudes, shortens calculation time, and improves detection accuracy. This is of great value in improving the speed and accuracy of mixed crude oil property detection, thereby enhancing the economic benefits of enterprises.

Description

Technical Field

[0001] The present invention relates to the field of crude oil processing in refining and chemical enterprises, and in particular to a method for detecting properties of mixed crude oil fractions with component tracking. Background Art

[0002] my country imports crude oil from diverse sources. While detailed laboratory data on the properties of crude oil from different sources is available, limited tank capacity at refineries means that crude oils with varying properties are often mixed and stored together. Consequently, the properties of these mixed crude oils in tanks can differ significantly from laboratory test results at the time of purchase. Currently, rapid testing of mixed crude oil properties is based on their NIR spectra, often using partial least squares or topological modeling techniques. While this method is accurate and effective for measuring overall properties of mixed crude oils, such as density and sulfur content, it struggles with determining the properties of a broad range of crude oil fractions, such as fraction yield and distillation temperature.

[0003] Earlier, we proposed "A method for detecting the fraction properties of mixed crude oil (202211462750.1)". This method is based on the near-infrared spectra of mixed crude oil and component crude oils. By optimizing the types and proportions of the component crude oils, the properties of the mixed crude oil can be detected more accurately. However, in the actual production of some refineries, if all crude oil purchased by the company is optimized as possible component crude oils, there are a large number of combinations, the solution space is too large, and the solution time is long. In addition, for a mixed crude oil, there are sometimes multiple combination solutions, and the solution is not robust enough, which means that similar mixed oil spectra may be the synthesis of different oil types and proportions. How to reduce the number of combinations, increase the solution speed, accurately locate the types of component crude oils, and further improve the detection accuracy will be an important task for refineries before conducting mixed crude oil property detection. Summary of the Invention

[0004] To address the problems in the prior art, this paper proposes a method for detecting the properties of mixed crude oil fractions with component tracking. This method tracks the components of crude oil from the moment it enters the enterprise, measures and records the types and quantities of crude oil in the storage tank, and thereby compresses and optimizes the solution scope, saving solution time and improving the robustness of the solution, thereby improving the accuracy of mixed crude oil property detection. The method includes the following steps:

[0005] 1. The crude oil purchased by the enterprise enters a storage tank in the tank area. u , the enterprise dispatching system provides the new crude oil type c v The amount of new crude oil can be obtained by recording the changes in the tank level sensor value before and after oil is added and consulting the tank capacity table. Real-time update of crude oil in storage tanks v Tank inventory Similarly, storage tank g uWhen the mixed crude oil is sent to the subsequent device, the oil output is obtained by recording the changes in the tank level sensor value before and after the oil is discharged and consulting the tank capacity table. At the same time, the tank inventory is updated in real time The storage tank after oil discharge g u Crude Oil v Tank inventory Updated by:

[0006]

[0007] 2. According to the tank g u Medium tank inventory Put the possible component crude oil types of the mixed crude oil into the component crude oil type dataset C possi ={c 1,possi ,c 2,possi ...c n,possi}, n is the number of crude oil types in the component crude oil type data set, and the initial proportion of each is K init =[k 1,init ,k 2,init ...k n,init ] T It is obtained from the following formula:

[0008]

[0009] in is the crude oil tank inventory of the i-th component of the mixed crude oil;

[0010] 3. Collect the near infrared spectra of the component crude oils and the mixed crude oils, and select 4000-4800 cm -1 The wavelength band is taken as the characteristic wavelength region spectrum, and the characteristic region spectrum is preprocessed by vector normalization and SG convolution smoothing to obtain the component crude oil preprocessed spectrum a i =[a 1i ,a 2i ,…,a mi ], i = 1, 2, ..., n, and the spectrum of the mixed crude oil after pretreatment A = [A1, A2, ..., A m ], m is the number of characteristic wavelength points of mixed crude oil;

[0011] 4. Use the following formula to optimize and solve the types and proportions of each component crude oil in the mixed crude oil:

[0012]

[0013] The constraints are:

[0014]

[0015] (1-α)ki,init ≤k i ≤min{1,(1+α)k 1,init},i=1,2,...,n

[0016] In the formula, α is usually set to 0.3~0.5, J(K) is the objective function, K is the proportion of each component crude oil, K=[k1,k2...k n ] T ,K≥0,a ji is the i-th component crude oil c i,possi The absorbance at the jth characteristic wavelength, c i,possi ∈C possi , A j is the absorbance of the mixed crude oil at the jth characteristic wavelength;

[0017] 5. Based on the obtained component crude oil types and proportions, estimate the properties of the mixed crude oil:

[0018]

[0019] Where L q is the property of the qth fraction of the mixed crude oil, k i is the i-th component crude oil c i,possi The proportion in the mixed crude oil, k i ∈K,l iq is the i-th component crude oil c i,possi The qth fraction property has been obtained by laboratory testing, and Q is the number of fraction properties tested.

[0020] Beneficial effects:

[0021] The present invention discloses a method for detecting the properties of mixed crude oil fractions with component tracking. This method addresses the problems of a large number of combinations in the optimization and solution process of current mixed crude oil property detection methods, as well as the possibility of multiple combination solutions for a single mixed crude oil. By using component tracking technology, the method optimizes the process of solving the types and proportions of the component crude oils of the mixed crude oil. Unlike existing methods, this method effectively reduces the number of component crude oil types to be solved by tracking and managing the components of the crude oil, and determines the initial proportions of the component crude oils, significantly shortening the calculation time. This is of great value in improving the speed and accuracy of mixed crude oil property detection, thereby improving the economic benefits of enterprises. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a flow chart of the mixed crude oil process in an embodiment of the present invention;

[0023] Figure 2 This is a flow chart of a method for detecting properties of mixed crude oil in a refinery with component tracking according to the present invention;

[0024] Figure 3 This is the near infrared spectrum of the mixed crude oil and its component crude oils after pretreatment in the embodiment of the present invention;

[0025] Figure 4 It is the compliance rate of the detection of properties of various mixed crude oils in the embodiment of the present invention. DETAILED DESCRIPTION

[0026] The present invention is further described below with reference to the accompanying drawings and specific examples. A specific operational process illustrates the effectiveness of this method in detecting the properties of mixed crude oil. This example is based on the technical solution of the present invention, but the scope of protection of the present invention is not limited to the following examples.

[0027] A certain refinery purchases more than 20 types of crude oil. When crude oil enters the company's storage tanks, it is often necessary to mix crude oils of different properties due to the limited number of tanks. Then, it is transported to the atmospheric and vacuum unit (CDU) for distillation. The process flow is as follows: Figure 1 As shown. Since there are many types of crude oil purchased by enterprises and a large number of combinations, the existing optimization solution method has the problems of long calculation time and insufficient detection accuracy. The present invention provides a mixed crude oil fraction property detection method with component tracking to solve the above problems. The method steps are as follows: Figure 2 Taking the property detection of mixed crude oil JZZ#05_220208 as an example, the specific process is as follows:

[0028] 1. Track and manage the components of the crude oil of the refinery and determine the inventory of crude oil storage tanks. u , record the crude oil type c v and new crude oil imports And update the crude oil in the tank in real time v Tank inventory Similarly, storage tank g u When the mixed crude oil is sent to the subsequent device, the oil output is obtained by recording the changes in the tank level sensor value before and after the oil is discharged and consulting the tank capacity table. gu , while updating the tank inventory in real time The storage tank after oil discharge g u Crude Oil v Tank inventory Updated by:

[0029]

[0030] For example, a company purchases crude oil crude 4 and stores it in tank G2. By recording the changes in the tank level sensor before and after the oil is added and consulting the tank capacity table, the company determines the amount of newly added crude oil. The inventory of crude oil crude 4 in tank G2 is updated in real time. The inventory of crude oil in tanks G1, G2, and G3 at a given moment is shown in Table 1. G1 holds three types of crude oil: crude 1, crude 2, and crude 3; G2 holds four types of crude oil: crude 4, crude 5, crude 6, and crude 7; and G3 holds two types of crude oil: crude 8 and crude 9.

[0031] Table 1 Inventory of storage tanks g1, g2 and g3 of a refinery

[0032]

[0033] 2. A storage tank in the tank area g u The inventory of the component crude oil tanks of the mixed crude oil JZZ#05_220208 is shown in Table 2. The possible component crude oil types of the mixed crude oil are put into the component crude oil type data set to obtain C possi ={c 1,possi ,c 2, possi ...c 8,possi}={crude4,crude6,crude3,crude8,crude 10 ,crude9,crude 11 ,crude 12}.

[0034] Table 2 Inventory of crude oil components in mixed crude oil JZZ#05_220208

[0035]

[0036] At the same time, the initial proportion of each is K init =[k 1,init ,k 2,init ...k 8,init ] T It is obtained from the following formula:

[0037]

[0038] in is the crude oil tank inventory of the i-th component of the mixed crude oil, where n is the component crude oil type dataset C possi The number of crude oil types in the component, for this embodiment, n = 8. Calculate the initial proportion of each crude oil component K init=[0.0427,0.1878,0.2134,0.1408,0.1664,0.1152,0.0764,0.0573] T .

[0039] 3. Collect C possi The near infrared spectrum of the crude oil with medium components was collected by near infrared spectrometer. The near infrared spectrum of the mixed crude oil JZZ#05_220208 was selected from 4000 to 4800 cm -1 The band is taken as the characteristic wavelength region spectrum, and the characteristic region spectrum is preprocessed by vector normalization and SG convolution smoothing.

[0040] Perform vector normalization preprocessing on the characteristic region spectrum of JZZ#05_220208:

[0041]

[0042] Where a (1×m) is the near-infrared spectrum of the mixed crude oil obtained by sampling, a=[a1,a2,...,a m ], a normalized is the near-infrared spectrum after vector normalization, and m is the number of characteristic wavelength points of the mixed crude oil. For this embodiment,

[0043] m=416

[0044]

[0045] Based on vector normalization, the SG convolution smoothing algorithm is used to reduce spectral noise and improve the signal-to-noise ratio. The SG convolution smoothing algorithm is used for each wavelength point on the near-infrared spectrum:

[0046]

[0047] In the formula, a p+d,normalizld is the absorbance at wavelength point p+d after vector normalization, a p,smooth is the absorbance at wavelength p after convolution smoothing, p = ω, ω + 1, ..., m - ω, ω is the half width of the smoothing window. When the window width is 15, ω = 7, and the cubic polynomial SG smoothing coefficient h d for

[0048] h=[-78,-13,42,87,122,147,162,167,162,147,122,87,42,-13,-78]

[0049] H is the normalization factor,

[0050]

[0051] The wave number of JZZ#05_220208 is 4588.3202cm -1 For example, the window width is selected as 15, and the spectral data near the wave number point is [0.08446233, 0.08468003, 0.08486874, 0.08515111,

[0052] 0.08555492,0.08594202,0.08614682,0.08612005,0.08598048,0.08587267,

[0053] 0.08584018,0.08586293,0.08591548,0.0859377,0.08587203], calculated wave number point 4588.3202 cm -1 The absorbance at a smooth =0.08595537.

[0054] Similarly, all wavenumber points of the JZZ#05_220208 characteristic region spectrum are calculated to obtain the spectrum a of the mixed crude oil near-infrared spectrum after vector normalization and SG convolution smoothing algorithm processing. s理计计th =[a 1,smooth ,a 2,smooth ,…,a m,smooth ], recorded as A=[A1,A2,...,A m ],like Figure 3 As shown, the figure also includes C possi The near infrared spectrum of the middle component crude oil obtained after the same pretreatment is a i =[a 1i ,a 2i ,...,a mi ], i=1,2,...,n.

[0055] 4. Calculate the types and proportions of each component crude oil in the mixed crude oil through optimization solution:

[0056]

[0057] The constraints are:

[0058]

[0059] (1-α)k i,init ≤k i ≤min{1,(1+α)k 1,init},i=1,2,...,n

[0060] α is usually set to 0.3-0.5, and for this embodiment, α=0.4. Where J(K) is the objective function, K is the proportion of each component crude oil, K=[l1,l2...k n ] T ,K≥0,a ji is the i-th component crude oil c i,possi The absorbance at the jth characteristic wavelength, c i,possi ∈C possi , A j is the absorbance of the mixed crude oil at the jth characteristic wavelength.

[0061] Solving the above objective function, we can get the proportions of the crude oil components K = [0.05, 0.22, 0.25, 0.11, 0.13, 0.09, 0.08, 0.06] T , that is, crude4 accounts for 0.05, crude6 accounts for 0.22, crude3 accounts for 0.25, crude8 accounts for 0.11, crude 10 Accounting for 0.13, crude9 accounts for 0.09, crude 11 0.08%, crude 12 It accounts for 0.06%.

[0062] 5. Based on the obtained component crude oil types and proportions, estimate the crude oil properties of the mixed crude oil JZZ#05_220208:

[0063]

[0064] Where L q is the property of the qth fraction of the mixed crude oil, k i is the proportion of the i-th component crude oil in the mixed crude oil, k i ∈K,l iq is the qth fraction property of the i-th component crude oil, which has been obtained by laboratory testing, and Q is the number of fraction properties tested.

[0065] For the mixed crude oil JZZ#05_220208 in this example, the test results of properties of some of its fractions are shown in Table 3, where the true values ​​are the laboratory test results.

[0066] Table 3 JZZ#05_220208 mixed crude oil property test results (taking distillate naphtha properties as an example)

[0067]

[0068]

[0069] In this example, 49 fraction properties of mixed crude oil JZZ#05_220208 were tested, and the compliance rate of the test results was 89.80%.

[0070] This method was used to detect the properties of mixed crude oil in multiple storage tanks in the tank area of ​​the refinery. The test results are as follows: Figure 4 As shown. Figure 4 The average compliance rate of the detection of the properties of the mixed crude oil in Zhong 14 was 86.14%, which is an improvement in accuracy compared with the existing methods.

[0071] In addition, tracking crude oil components can effectively reduce the number of component crude oil types during the optimization process, and provide the initial proportions of each component crude oil as constraints, significantly shortening the calculation time and meeting the real-time application needs of enterprises.

Claims

1. A method for detecting properties of mixed crude oil fractions with component tracking, characterized in that Tracking the components of crude oil from the moment it enters the enterprise, measuring and recording the types and quantities of crude oil in the storage tanks, and thus improving the accuracy of mixed crude oil property detection, involves the following steps: 1) The crude oil purchased by the enterprise enters a storage tank in the tank area u , record the crude oil type c v and new crude oil imports And update the crude oil in the tank in real time v Tank inventory Similarly, storage tank g u Record the oil output when the mixed crude oil is sent to the subsequent device And update the tank inventory in real time Oil storage tank g u Crude Oil v Tank inventory Updated by: 2) According to the tank g u Medium tank inventory Put the possible components of the mixed crude oil into the component crude oil type dataset C possi ={c 1,possi ,c 2,possi …c n,possi }, and get the initial proportion K init =[k 1,init ,k 2,init …k n,init ] T , n is the number of crude oil types in the component crude oil type data set; storage tank g u The initial proportion of crude oil components is k i,init It is obtained from the following formula: i=1,2,…,nwhere is the crude oil tank inventory of the i-th component of the mixed crude oil, and the initial proportion of each component crude oil K is obtained init =[k 1,init ,k 2,init …k n,init ] T ; 3) Collect the near infrared spectrum of the component crude oil, collect the near infrared spectrum of the mixed crude oil, and perform the same spectrum preprocessing on the component crude oil and the mixed crude oil to obtain the spectrum a after preprocessing of the component crude oil i =[a 1i ,a 2i ,…,a mi ], i = 1, 2, ..., n, and the spectrum of the mixed crude oil after pretreatment A = [A1, A2, ..., A m ], m is the number of characteristic wavelength points of mixed crude oil; 4) Use the following formula to optimize and solve the types and proportions of each component crude oil in the mixed crude oil: The constraints are: (1-a)k i,init ≤k i ≤min{1,(1+α)k 1,init },i=1,2,…,n Where J(K) is the objective function, K is the proportion of each component crude oil, K=[k1,k2…k n ] T ,K≥0,a ji is the i-th component crude oil c i,possi The absorbance at the jth characteristic wavelength, c i,possi ∈C possi , A j is the absorbance of the mixed crude oil at the jth characteristic wavelength, and α is the coefficient; 5) Based on the obtained component crude oil types and proportions, the following formula is used to estimate the properties of the mixed crude oil: Where L q is the property of the qth fraction of the mixed crude oil, k i is the i-th component crude oil c i,possi The proportion in the mixed crude oil, k i ∈K,l iq is the i-th component crude oil c i,possi The qth fraction property has been obtained by laboratory testing, and Q is the number of fraction properties tested.

2. A method for detecting properties of mixed crude oil fractions with component tracking according to claim 1, characterized in that The type of new crude oil is given by the enterprise scheduling system.

3. A method for detecting properties of mixed crude oil fractions with component tracking according to claim 1, characterized in that New crude oil volume and oil output from the tank Measured by the tank level sensor: record the tank level changes before and after oil is added, and obtain the tank capacity table by consulting the tank capacity table and 4. A method for detecting properties of mixed crude oil fractions with component tracking according to claim 1, characterized in that The same spectral preprocessing was performed on the component crude oils and the mixed crude oils, including spectral range selection, vector normalization and SG convolution smoothing and denoising.

5. The method for detecting properties of mixed crude oil fractions with component tracking according to claim 1, characterized in that The near-infrared spectrum of crude oil ranges from 4000 to 4800 cm -1 band.

6. A method for detecting properties of mixed crude oil fractions with component tracking according to claim 1, characterized in that In the optimization solution constraint conditions, α is usually taken as 0.3 to 0.5.

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