阅读说明：本技术 一种原油含水率检测方法 (Method for detecting water content of crude oil ) 是由 孟敏 刘二余 杨雷 张延海 邓旋科 于 2021-08-25 设计创作，主要内容包括：本发明属于检测方法,具体涉及一种原油含水率检测方法。一种原油含水率检测方法,包括下述步骤：步骤1：确定温度修正参数；步骤2：检测原油含水率；步骤3：修正原油含水率。本发明的显著效果是：本申请以微波检测法为主要方法,针对微波检测法实施过程中温度误差和采样频率误差造成的缺陷进行改进,提前使用其他方法对微波检测法使用的设备的温漂进行修正,对于采样频率固定的设备,通过泰勒展开式对采样空白区域进行近似,得到最为接近的估计值。(The invention belongs to a detection method, and particularly relates to a method for detecting the water content of crude oil. A method for detecting the water content of crude oil comprises the following steps: step 1: determining a temperature correction parameter; step 2: detecting the water content of the crude oil; and step 3: and correcting the water content of the crude oil. The invention has the following remarkable effects: the method mainly uses a microwave detection method, improves defects caused by temperature errors and sampling frequency errors in the implementation process of the microwave detection method, corrects the temperature drift of equipment used by the microwave detection method by using other methods in advance, and approximates a sampling blank area by a Taylor expansion mode for equipment with fixed sampling frequency to obtain the closest estimated value.)

1. The method for detecting the water content of the crude oil is characterized by comprising the following steps of:

step 1: determining a temperature correction parameter;

step 2: detecting the water content of the crude oil;

and step 3: and correcting the water content of the crude oil.

2. The method for detecting the water content of crude oil as claimed in claim 1, wherein: the step 1 includes the following steps,

step 1.1: sampling

Sampling is carried out in the range of-30 ℃ to 80 ℃, from-30 ℃, every time the temperature rises to 1 ℃ is taken as a temperature sampling point, until the temperature reaches 80 ℃, two samples are collected at each temperature sampling point, and a two-sample sequence is formed and is marked as A_iSequence and B_iSequence, wherein i ═ 1,2,3 … 111, wherein A_iAnd B_iCorresponding to a sampling at-30 deg.C, A₂And B₂Corresponding to a sampling of-29 deg.C, …, A₁₁₁And B₁₁₁Corresponding to the sampling at the temperature of 80 ℃,

step 1.2: separately detecting water content of crude oil

Detecting the water content of the crude oil by using a microwave detection method and any one of other methods, and respectively recording as P_iAnd Q_i，

Wherein P is_iIndicating the water content, i.e. P, of the crude oil sample as determined by the microwave detection method₁Corresponding to the water content, P, of the sampled sample at-30 DEG C₂Corresponding to the water content of a sample at-29 ℃, …, P₁₁₁Corresponding to the water content of the sample sampled at 80 ℃;

similarly, Q_iIndicating water content, i.e. Q, of crude oil samples determined by non-microwave detection₁Corresponding to the water content, Q, of a sampled sample at-30 DEG C₂Corresponding to the water content of a sample at-29 ℃, …, Q₁₁₁Corresponding to the water content of the sample sampled at 80 ℃,

the temperature error value Δ T_iCan calculate

ΔT_i＝Q_i-P_i

Namely, the error of the water content at each temperature can be obtained,

obtaining a comparison table of the temperature and the water content error.

3. The method for detecting water content of crude oil as claimed in claim 2, wherein: said step 1 further comprises the following steps,

step 1.3: temperature step self-adaptive adjustment

Step 1.3.1: average temperature error value

Mean temperature error valueIs calculated by the following formula

Wherein Δ T_iThe temperature error value in the sequence, which is the sequence obtained in step 1.2 at the time of the first calculation, is used in the subsequent calculations with the sequence value obtained in the previous cycle calculation;

n is the total number of sequences, the value of N is 111 in the first calculation, the value obtained in the previous period calculation is used in the subsequent calculation,

step 1.3.2: judgment of

The following two inequalities are judged,

wherein both of the above inequalities are calculated starting from i-2,

if the two inequalities are both true, recording all temperature values and error values corresponding to the temperatures, forming a comparison table of the temperature and the water content error, and executing the step 2; otherwise, a step 1.3.3 is executed,

step 1.3.3: temperature step adjustment

At Δ T_iCorresponding temperature t_iAnd Δ T_i-1Corresponding temperature t_i-1Is increased by a temperatureExecuting step 1.1 and step 1.2 at the temperature point, inserting the new temperature and the corresponding error of the temperature into the original temperature sequence and error sequence, and then executing the stepIn the step 1.3, the step of,

when this step is executed, the calculation is started from i ═ 2 until i ═ N ends, and as one cycle period, three cycle periods are executed at most, and when the three cycle periods are completed, no matter whether the inequalities of step 1.3.2 are all true or not, step 2 is executed,

and obtaining a comparison table of the temperature and the water content error after the temperature step length is adjusted.

4. The method for detecting water content of crude oil as claimed in claim 3, wherein: said step 2 comprises the following steps,

detection of water content f of crude oil by microwave detection_iSimultaneously recording the temperature and time of detection, wherein the temperature is t_iDenotes time by k_iThe index i in the above parameters indicates the number of detections.

5. The method for detecting water content of crude oil as claimed in claim 4, wherein: said step 3 comprises the following steps,

calculating the corrected water content f of the crude oil by the following formula_{Repair i}

f_{Repair i}＝f_i+T_{Repair i}

Wherein f is_iDetecting the water content, T, of the crude oil by using a microwave detection method in the step 2_{Repair i}Obtained by the following method

First using the temperature t_iLooking up the error comparison table of the temperature and the water content in the step 1 if the temperature t is_iFalls within the interval [ t_a，t_b]Then take t_a，t_bCorresponding temperature error value Delta T_aAnd a temperature error value Δ T_bParticipate in subsequent calculations, where t_a，t_bAll are temperature values in the comparison table of the temperature and the water content error obtained in the step 1, and t_bAnd t_aThe difference is 1 ℃,

if the temperature t is_iA certain temperature t just equal to the error between the temperature and the water content in the step 1_aIf the two are completely consistent, t is taken_aCorresponding temperature error value Delta T_aAfter participating inContinuing to calculate;

then, T is calculated by the following formula_{Repair i}

6. The method for detecting water content of crude oil as claimed in claim 5, wherein: the method further comprises the step of,

and 4, step 4: judgment of

If the moisture content change of two adjacent detections exceeds 10%, executing step 5, otherwise, circularly executing step 2 and step 3, namely

If the following is true, step 5 is performed, otherwise steps 2 and 3 are performed in a loop,

and 5: calculating water content between samples

To f_{Repair i-1}And f_{Repair i}Taylor expansions are performed separately, the expansion being kept at 10 orders for the time k_i-1And time k_iAt any time point k in between_aAll can calculate k by the following formula_aWater content f of crude oil at time_k

Technical Field

The invention belongs to a detection method, and particularly relates to a method for detecting the water content of crude oil.

Background

Petroleum, known as "industrial blood", is one of the most important raw materials in modern organic chemical industry. With the continuous and rapid development of the economy of China, the increase of the petroleum yield is far from meeting the dependence of the development of the economy of China on petroleum, and the import of petroleum accounts for 30 percent of the petroleum consumption of China. Therefore, in the processes of crude oil production, storage and transportation, the water content of crude oil is a very important parameter index in the production and development of crude oil, and the quality of the crude oil and the development cost thereof are directly influenced.

In the prior art, methods for measuring the water content of crude oil mainly fall into two categories: (1) an off-line manual measurement method mainly comprises a distillation method, an electric desorption method and a Karl Fischer method; (2) the on-line real-time measuring method mainly comprises an electrical method (a conductivity method, a capacitance method and an electromagnetic method), a radio frequency method, a microwave detection method, a microwave transmission method, a light probe method, an infrared spectroscopy method, a nuclear magnetic resonance method and the like.

The microwave detection method is a method of irradiating a specific region with microwaves, collecting data signals of transmitting-end and receiving-end microwaves, and estimating the water content of crude oil by comparing the attenuation of the microwaves. The method can realize on-line detection, and the detection efficiency is higher.

The defects of the existing microwave detection method are concentrated and shown as follows: (1) the generation of the microwave depends on radioactive isotopes, so that the microwave can hurt the health of a working human body; (2) the difference between the attenuation parameters of the pure water and the pure oil is smaller, so that the precision is sometimes poorer; (3) the precision of the equipment is greatly influenced by the environmental temperature; (4) once the water content of the crude oil is changed drastically, the detection frequency of the equipment may not meet the detection requirement.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a method for detecting the water content of crude oil.

The invention is realized by the following steps: a method for detecting the water content of crude oil comprises the following steps:

step 1: determining a temperature correction parameter;

step 2: detecting the water content of the crude oil;

and step 3: and correcting the water content of the crude oil.

The method for detecting the water content of the crude oil comprises the following steps of 1,

step 1.1: sampling

Sampling is carried out in the range of-30 ℃ to 80 ℃, from-30 ℃, every time the temperature rises to 1 ℃ is taken as a temperature sampling point, until the temperature reaches 80 ℃, two samples are collected at each temperature sampling point, and a two-sample sequence is formed and is marked as A_iSequence and B_iA sequence wherein i ═ 1,2,3 … 111, whereinA_iAnd B_iCorresponding to a sampling at-30 deg.C, A₂And B₂Corresponding to a sampling of-29 deg.C, …, A₁₁₁And B₁₁₁Corresponding to the sampling at the temperature of 80 ℃,

step 1.2: separately detecting water content of crude oil

Detecting the water content of the crude oil by using a microwave detection method and any one of other methods, and respectively recording as P_iAnd Q_i，

Wherein P is_iIndicating the water content, i.e. P, of the crude oil sample as determined by the microwave detection method₁Corresponding to the water content, P, of the sampled sample at-30 DEG C₂Corresponding to the water content of a sample at-29 ℃, …, P₁₁₁Corresponding to the water content of the sample sampled at 80 ℃;

similarly, Q_iIndicating water content, i.e. Q, of crude oil samples determined by non-microwave detection₁Corresponding to the water content, Q, of a sampled sample at-30 DEG C₂Corresponding to the water content of a sample at-29 ℃, …, Q₁₁₁Corresponding to the water content of the sample sampled at 80 ℃,

the temperature error value Δ T_iCan calculate

ΔT_i＝Q_i-P_i

Namely, the error of the water content at each temperature can be obtained,

obtaining a comparison table of the temperature and the water content error.

The method for detecting the water content of the crude oil comprises the following steps of 1,

step 1.3: temperature step self-adaptive adjustment

Step 1.3.1: average temperature error value

Mean temperature error valueIs calculated by the following formula

Wherein Δ T_iIs the temperature in the sequenceAn error value, which is the sequence obtained in step 1.2 during the first calculation, and which is the sequence value obtained in the previous cycle calculation used in the subsequent calculation;

n is the total number of sequences, the value of N is 111 in the first calculation, the value obtained in the previous period calculation is used in the subsequent calculation,

step 1.3.2: judgment of

The following two inequalities are judged,

wherein both of the above inequalities are calculated starting from i-2,

if the two inequalities are both true, recording all temperature values and error values corresponding to the temperatures, forming a comparison table of the temperature and the water content error, and executing the step 2; otherwise, a step 1.3.3 is executed,

step 1.3.3: temperature step adjustment

At Δ T_iCorresponding temperature t_iAnd Δ T_i-1Corresponding temperature t_i-1Is increased by a temperatureStep 1.1 and step 1.2 are executed at the temperature point, the new temperature and the corresponding error of the temperature are inserted into the original temperature sequence and the error sequence, then step 1.3 is executed,

when this step is executed, the calculation is started from i ═ 2 until i ═ N ends, and as one cycle period, three cycle periods are executed at most, and when the three cycle periods are completed, no matter whether the inequalities of step 1.3.2 are all true or not, step 2 is executed,

and obtaining a comparison table of the temperature and the water content error after the temperature step length is adjusted.

The method for detecting the water content of the crude oil is characterized in that the step 2 comprises the following steps,

detection of water content f of crude oil by microwave detection_iSimultaneously recording the temperature and time of detection, wherein the temperature is t_iDenotes time by k_iThe index i in the above parameters indicates the number of detections.

The method for detecting the water content of the crude oil, wherein the step 3 comprises the following steps,

calculating the corrected water content f of the crude oil by the following formula_{Repair i}

f_{Repair i}＝f_i+T_{Repair i}

Wherein f is_iDetecting the water content, T, of the crude oil by using a microwave detection method in the step 2_{Repair i}Obtained by the following method

First using the temperature t_iLooking up the error comparison table of the temperature and the water content in the step 1 if the temperature t is_iFalls within the interval [ t_a，t_b]Then take t_a，t_bCorresponding temperature error value Delta T_aAnd a temperature error value Δ T_bParticipate in subsequent calculations, where t_a，t_bAll are temperature values in the comparison table of the temperature and the water content error obtained in the step 1, and t_bAnd t_aThe difference is 1 ℃,

if the temperature t is_iA certain temperature t just equal to the error between the temperature and the water content in the step 1_aIf the two are completely consistent, t is taken_aCorresponding temperature error value Delta T_aParticipating in subsequent calculation;

then, T is calculated by the following formula_{Repair i}

The method for detecting the water content of the crude oil further comprises the following steps,

and 4, step 4: judgment of

If the moisture content change of two adjacent detections exceeds 10%, executing step 5, otherwise, circularly executing step 2 and step 3, namely

If the following is true, step 5 is performed, otherwise steps 2 and 3 are performed in a loop,

and 5: calculating water content between samples

To f_{Repair i-1}And f_{Repair i}Taylor expansions are performed separately, the expansion being kept at 10 orders for the time k_i-1And time k_iAt any time point k in between_aAll can calculate k by the following formula_aWater content f of crude oil at time_k

The invention has the following remarkable effects: the method mainly uses a microwave detection method, improves defects caused by temperature errors and sampling frequency errors in the implementation process of the microwave detection method, corrects the temperature drift of equipment used by the microwave detection method by using other methods in advance, and approximates a sampling blank area by a Taylor expansion mode for equipment with fixed sampling frequency to obtain the closest estimated value.

Detailed Description

A method for detecting the water content of crude oil comprises the following steps:

step 1: determining temperature correction parameters

Step 1.1: sampling

Sampling is carried out in the range of-30 ℃ to 80 ℃, and from-30 ℃, every time the temperature rises by 1 ℃ is taken as a temperature sampling point until the temperature reaches 80 ℃. Two samples were collected at each temperature sampling point to form a two sample sequence, denoted A_iSequence and B_iSequence of i wherein1,2,3 … 111, wherein a_iAnd B_iCorresponding to a sampling at-30 deg.C, A₂And B₂Corresponding to a sampling of-29 deg.C, …, A₁₁₁And B₁₁₁Corresponding to a sample at 80 deg.c.

Step 1.2: separately detecting water content of crude oil

Detecting the water content of the crude oil by using a microwave detection method and any one of other methods, and respectively recording as P_iAnd Q_i。

Wherein P is_iIndicating the water content, i.e. P, of the crude oil sample as determined by the microwave detection method₁Corresponding to the water content, P, of the sampled sample at-30 DEG C₂Corresponding to the water content of a sample at-29 ℃, …, P₁₁₁Corresponding to the water content of the sample sampled at 80 ℃;

similarly, Q_iIndicating water content, i.e. Q, of crude oil samples determined by non-microwave detection₁Corresponding to the water content, Q, of a sampled sample at-30 DEG C₂Corresponding to the water content of a sample at-29 ℃, …, Q₁₁₁Corresponding to the water content of the sample sampled at 80 ℃.

The temperature error value Δ T_iCan calculate

ΔT_i＝Q_i-P_i

That is, the moisture content error at each temperature can be obtained.

Any other method is a method for detecting the water content of the crude oil, which is not a microwave detection method. The method should meet the principle of high detection accuracy. As an example, other processes in the present application use distillation. Of course, one skilled in the art could choose any of the other existing methods.

As an extension of this step, when other methods (comparison methods) are used, more than one method may be used, for example, when sampling, multiple samples are taken at each temperature point, and the moisture content is determined for each sample by different methods, such as distillation and density methods, at which time multiple sets of detection data are obtained, and when calculating the moisture content error at each temperature, the moisture contents determined by the other comparison methods are first unified and then compared with the moisture content determined by the microwave detection method. This approach is also possible, but with each additional approach, the detection time and cost would be correspondingly increased.

Step 1.3: temperature step self-adaptive adjustment

Step 1.3.1: average temperature error value

Mean temperature error valueIs calculated by the following formula

Wherein Δ T_iThe temperature error value in the sequence, which is the sequence obtained in step 1.2 at the time of the first calculation, is used in the subsequent calculations with the sequence value obtained in the previous cycle calculation;

n is the total number of sequences, and in the first calculation, the value of N is 111, and in the subsequent calculation, the value obtained in the previous cycle calculation is used.

Step 1.3.2: judgment of

The following two inequalities are judged,

wherein both inequalities are calculated starting from i-2.

If the two inequalities are both true, recording all temperature values and error values corresponding to the temperatures, forming a comparison table of the temperature and the water content error, and executing the step 2; otherwise, step 1.3.3 is executed.

Step 1.3.3: temperature step adjustment

At Δ T_iCorresponding temperature t_iAnd Δ T_i-1Corresponding temperature t_i-1Is increased by a temperatureAnd (3) executing the step 1.1 and the step 1.2 at the temperature point, inserting the new temperature and the error corresponding to the temperature into the original temperature sequence and the error sequence, and then executing the step 1.3.

When this step is executed, the calculation is started from i ═ 2 until i ═ N ends, and as one cycle period, three cycle periods are executed at most, and when the three cycle periods are completed, step 2 is executed regardless of whether the inequalities of step 1.3.2 are all true or not.

Finally, a comparison table of the temperature and the water content error is obtained in the step.

Step 2: detecting water content of crude oil

Detection of water content f of crude oil by microwave detection_iSimultaneously recording the temperature and time of detection, wherein the temperature is t_iDenotes time by k_iThe index i in the above parameters indicates the number of detections.

And step 3: correction of crude oil Water content

Calculating the corrected water content f of the crude oil by the following formula_{Repair i}

f_{Repair i}＝f_i+T_{Repair i}

Wherein f is_iDetecting the water content, T, of the crude oil by using a microwave detection method in the step 2_{Repair i}Obtained by the following method

First using the temperature t_iLooking up the error comparison table of the temperature and the water content in the step 1 if the temperature t is_iFalls within the interval [ t_a，t_b]Then take t_a，t_bCorresponding temperature error value Delta T_aAnd a temperature error value Δ T_bParticipate in subsequent calculations, where t_a，t_bAll are temperature values in the comparison table of the temperature and the water content error obtained in the step 1, and t_bAnd t_aThe difference is 1 ℃.

If the temperature t is_iA certain temperature t just equal to the error between the temperature and the water content in the step 1_aIf the two are completely consistent, t is taken_aCorresponding temperature error value Delta T_aParticipating in subsequent calculation;

then, T is calculated by the following formula_{Repair i}

And 4, step 4: judgment of

If the moisture content change of two adjacent detections exceeds 10%, executing step 5, otherwise, circularly executing step 2 and step 3, namely

If the following is true, step 5 is performed, otherwise steps 2 and 3 are performed in a loop,

and 5: calculating water content between samples

To f_{Repair i-1}And f_{Repair i}Taylor expansions are performed separately, the expansion being kept at 10 orders for the time k_i-1And time k_iAt any time point k in between_aAll can calculate k by the following formula_aWater content f of crude oil at time_k