CN107796749B - Corrosion inhibitor optimization and corrosion prevention effect evaluation test device and method - Google Patents
Corrosion inhibitor optimization and corrosion prevention effect evaluation test device and method Download PDFInfo
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Abstract
The invention relates to a corrosion inhibitor optimization and corrosion prevention effect evaluation test device and a corrosion inhibitor optimization and corrosion prevention effect evaluation test method, which belong to the technical field of petroleum and natural gas engineering. Designing a pre-filming system, and coating the pipeline to be pre-filmed in a laboratory through a pre-filming device to ensure that the thickness of the corrosion inhibitor film on the inner wall of the pre-filmed pipeline is uniform; and designing a corrosion rate detection method, and evaluating the corrosion inhibition effect of the corrosion inhibitor by combining a weight loss method and a dichloromethane solution cleaning method. The corrosion inhibitor optimization and corrosion prevention effect evaluation test device and method provided by the invention can evaluate and optimize the corrosion inhibitor and improve the corrosion prevention effect of the corrosion inhibitor.
Description
Technical Field
The invention relates to a corrosion inhibitor optimization and anticorrosion effect evaluation test device and method, and belongs to the technical field of petroleum and natural gas engineering.
Background
High H content in acid gas field of China2S、CO2The corrosion problem in the development process is very prominent. The gas field corrosion protection process technology comprises the steps of adopting a corrosion-resistant material, an anti-corrosion coating, adding a corrosion inhibitor, protecting a cathode and the like. The corrosion control method of the corrosion inhibitor pre-film has the advantages of low investment and good corrosion prevention effect, and is widely applied. The development of high-sulfur gas fields is still a minority of China, corresponding corrosion inhibitor evaluation, optimization methods and standards are lacked, and theoretical research and experimental verification on aspects of corrosion inhibitor optimization, corrosion inhibition effect evaluation and the like are needed in order to improve corrosion inhibitor corrosion inhibition efficiency and corrosion inhibition effect of gas field gathering and transportation pipelines.
The corrosion inhibitor evaluation and optimization experiment performed in the traditional laboratory cannot simulate the real flowing state of the corrosion inhibitor in the pipeline, and the experiment result is not necessarily close to the actual working condition. Patent CN201611224268.9 discloses a method for evaluating corrosion inhibition efficiency of corrosion inhibitor, which designs one or more combinations of experimental parameters of experiment temperature, pressure, partial pressure of corrosion medium, flow rate of corrosion medium, and injection concentration of corrosion inhibitor in a corrosion inhibitor evaluation experiment according to the collected corrosion working condition parameters of the gas well or gas field to which the corrosion inhibitor is to be applied, develops a corrosion inhibitor evaluation experiment, and processes the experiment result to evaluate corrosion inhibition efficiency of the corrosion inhibitor. Patent CN201620832592.8 discloses a novel test device of indoor corrosion inhibitor evaluation, through set up hydrothermal synthesis reation kettle support in the oil bath pot, be equipped with the couple on the support, the oil bath pot is provided with oil bath pot cover outward, and in the corrosion inhibitor evaluation experimentation, the oil bath smell can not spill. Patent CN201710021368.X discloses an evaluation method of a corrosion inhibitor of a crude oil gathering and transportation system, which comprises the steps of measuring a phase transition point from an oil-in-water system to an oil-in-water system in the crude oil gathering and transportation system to obtain the suddenly-reduced water content of the crude oil gathering and transportation system when the crude oil gathering and transportation system is strongly corroded, and carrying out a corrosion inhibitor performance evaluation experiment and using the suddenly-reduced water content of the crude oil gathering and transportation system as an on-site corrosion inhibitor filling index. Patent CN201420453175.3 discloses a corrosion inhibitor evaluation device containing corrosive dissolved gas medium, which can screen and compare multiple types of corrosion inhibitors and evaluate corrosion inhibitors with different dosage simultaneously under the condition of on-site medium. The indoor evaluation has the advantage that the test conditions can be flexibly regulated, but even if sampling is carried out from the site in the experimental process, the corrosive medium is gradually consumed, so that the indoor evaluation is difficult to simulate the same as the actual situation on the site, and particularly the test medium containing the corrosive gas is difficult to simulate.
Therefore, the invention designs a corrosion inhibitor optimization and anticorrosion effect evaluation test device and method, tests and simulates the working condition of an acid gas field gathering and transportation system, establishes the corrosion inhibitor optimization and anticorrosion effect evaluation test device, can perform a corrosion inhibitor optimization test, a corrosion inhibitor film durability evaluation test, a corrosion inhibitor anticorrosion effect evaluation test and a corrosion inhibitor and methanol compatibility research test, has the same test medium and test working condition as the actual working condition on site, and has real and reliable test data.
Disclosure of Invention
The invention aims to provide a corrosion inhibitor optimization and corrosion prevention effect evaluation test device and method, so that corrosion inhibitors can be better evaluated and optimized, the corrosion inhibition rate is increased, and the safe operation of an acid gas field gathering pipeline is ensured.
The invention mainly solves the following problems: 1. by designing a corrosion inhibitor optimization and corrosion prevention effect evaluation test device, carrying out tests such as corrosion inhibitor optimization, corrosion inhibitor film durability evaluation, corrosion inhibitor corrosion prevention effect evaluation, corrosion inhibitor and methanol compatibility research, and carrying out test research on corrosion inhibition efficiency, film durability and methanol compatibility of the corrosion inhibitor; 2. designing a pre-filming system, and pre-filming the pipeline through the system; 3. designing a pre-filming device, and enabling the corrosion inhibitor to be fully contacted with the top of a pipeline to be pre-filmed under the action of external force, so as to avoid the thickness of the corrosion inhibitor on the top from being too low; 4. and designing a corrosion rate detection method, and evaluating the corrosion inhibition effect of the corrosion inhibitor by combining a weight loss method and a dichloromethane solution cleaning method.
In order to achieve the above object, the present invention has the following technical means.
A corrosion inhibitor is preferred and anticorrosive effect evaluation test device includes: an acid natural gas pipeline 1, a fuel gas pipeline 2, a first fuel gas inlet valve 3, an acid gas inlet valve 4, a temperature sensor 5, a pressure sensor 6, a control group test area 7, a corrosion coupon 8, a resistance probe 9, a corrosion inhibitor filling point 10, a methanol filling point 11, a corrosion inhibitor filling pry 12, a methanol filling pry 13, a corrosion test area 14, a flange 15, a first test gas inlet valve 16, a second test gas inlet valve 17, a third test gas inlet valve 18, a first test gas outlet valve 19, a second test gas outlet valve 20, a third test gas outlet valve 21, a first fuel gas purging valve 22, a second fuel gas purging valve 23, a third fuel gas purging valve 24, a fourth fuel gas purging valve 25, a fifth fuel gas purging valve 26, a gas-water separator 27, an acid natural gas outlet valve 28, a liquid taking device 29, a pre-membrane system 30 and a pre-membrane device 315;
the first fuel gas inlet valve 3 and the acid gas inlet valve 4 are connected with the acid natural gas pipeline 1 and the fuel gas pipeline 2, the temperature sensor 5 and the pressure sensor 6 are symmetrically distributed on a test loop, the comparison group test area 7 is arranged at the inlet of the loop, the corrosion hanging sheet 8 and the resistance probe 9 are arranged on the comparison group test area 7 to monitor the corrosion rate of the pipeline, the corrosion inhibitor filling point 10 and the methanol filling point 11 are respectively connected with the corrosion inhibitor filling pry 12 and the methanol filling pry 13, the corrosion test area 14 and the gas-water separator 27 are sequentially connected, and the acid natural gas outlet valve 28 and the liquid taking device 29 are connected with the gas-water separator 27.
Further, the corrosion test area 14 includes: a first test module 150, a second test module 151, a third test module 152, a first pre-membrane line 141, a second pre-membrane line 142, a third pre-membrane line 143, a fourth pre-membrane line 144, a fifth pre-membrane line 145, a sixth pre-membrane line 146, a seventh pre-membrane line 147, an eighth pre-membrane line 148, a ninth pre-membrane line 149; the first pre-membrane pipeline 141, the second pre-membrane pipeline 142 and the third pre-membrane pipeline 143 are assembled in a first test module 150, the fourth pre-membrane pipeline 144, the fifth pre-membrane pipeline 145 and the sixth pre-membrane pipeline 146 are assembled in a second test module 151, the seventh pre-membrane pipeline 147, the eighth pre-membrane pipeline 148 and the ninth pre-membrane pipeline 149 are assembled in a third test module 152, 9 pre-membrane pipelines are connected with a test loop through a flange 15, and 9 pre-membrane pipelines are pre-membrane through the pre-membrane system 30.
Furthermore, the tests which can be carried out by the corrosion inhibitor optimization and corrosion prevention effect evaluation test device comprise: the method comprises the following steps of a corrosion inhibitor optimization test, a corrosion inhibitor film durability evaluation test, a corrosion inhibitor anticorrosion effect evaluation test and a corrosion inhibitor and methanol compatibility research test, wherein the specific steps of each test are as follows:
(1) the corrosion inhibitor optimization test comprises the following specific steps:
s1, connecting a testing device, removing sundries in a testing loop, checking the sealing property between pipe sections, ensuring that no leakage exists between a pipeline and a valve, and zeroing the temperature sensor 5 and the pressure sensor 6;
s2, designing and connecting a pre-membrane system 30, weighing 9 pipelines to be pre-membrane to be accurate to 0.1g, pre-membrane the 9 pipelines to be pre-membrane according to the corrosion inhibitor pre-membrane operation steps, wherein the first pre-membrane pipeline 141, the second pre-membrane pipeline 142 and the third pre-membrane pipeline 143 use (A) type corrosion inhibitor pre-membrane, the fourth pre-membrane pipeline 144, the fifth pre-membrane pipeline 145 and the sixth pre-membrane pipeline 146 use (B) type corrosion inhibitor pre-membrane, and the seventh pre-membrane pipeline 147, the eighth pre-membrane pipeline 148 and the ninth pre-membrane pipeline 149 use (C) type corrosion inhibitor pre-membrane;
s3, assembling 9 pre-film pipelines on the corrosion test area 14, wherein each pre-film pipeline is connected with the test loop through a flange 15;
s4, installing a corrosion hanging sheet 8 and a resistance probe 9 on the control group test area 7;
s5, opening the acid gas inlet valve 4, the first test gas inlet valve 16, the second test gas inlet valve 17, the third test gas inlet valve 18, the first test gas outlet valve 19, the second test gas outlet valve 20, the third test gas outlet valve 21 and the acid natural gas outlet valve 28; closing the first fuel gas inlet valve 3, the first fuel gas purging valve 22, the second fuel gas purging valve 23, the third fuel gas purging valve 24, the fourth fuel gas purging valve 25 and the fifth fuel gas purging valve 26;
s6, recording readings of a corrosion hanging sheet 8 and a resistance probe 9 on the control group test area 7 in the test process, and monitoring the corrosion rate of the pipeline on the control group test area 7; taking liquid from the liquid taking device 29 at regular time, and detecting the residual concentration of the corrosion inhibitor by using a corrosion inhibitor residual concentration analysis method;
s7, performing the test for 10-60 d, and closing the acid gas inlet valve 4;
s8, purging the test device according to the first purging process;
s9, after purging for 1h, detecting the concentration and the oxygen content of hydrogen sulfide by using a multifunctional gas monitor at a large-range pressure gauge vent port, closing the first fuel gas inlet valve 3 when the content of hydrogen sulfide is lower than 20ppm and the content of oxygen is lower than 2%, and stopping purging;
s10, disassembling 9 pre-film pipelines assembled on the corrosion test area 14, loading and transporting to a laboratory, and processing according to the corrosion rate detection step;
s11, selecting 9 pre-film pipelines with low corrosion rate and large residual corrosion inhibitor amount, and preferably selecting a corrosion inhibitor with better corrosion inhibition effect;
(2) the corrosion inhibitor film durability evaluation test comprises the following specific steps:
m1, zeroing the temperature sensor 5 and the pressure sensor 6 on the test loop;
m2, weighing 9 pipelines to be pre-coated to the accuracy of 0.1g, and pre-coating the 9 pipelines to be pre-coated according to the corrosion inhibitor pre-coating operation steps;
m3, repeating the steps S3-S6;
m4, after the test is carried out for 10d, purging the first test module 150 according to a second purging process, detaching the first pre-film pipeline 141, the second pre-film pipeline 142 and the third pre-film pipeline 143 after purging is finished, loading and transporting to a laboratory, and processing according to the corrosion rate detection step;
m5, after the test is carried out for 20d, purging the second test module 151 according to a third purging process, detaching the fourth pre-film pipeline 144, the fifth pre-film pipeline 145 and the sixth pre-film pipeline 146 after purging is finished, loading and transporting the products to a laboratory, and processing the products according to the corrosion rate detection step;
m6, after the test is carried out for 30d, purging the third test module 152 according to a fourth purging flow, detaching the seventh pre-film pipeline 147, the eighth pre-film pipeline 148 and the ninth pre-film pipeline 149 after the purging is finished, loading and transporting the materials to a laboratory, and processing the materials according to the corrosion rate detection step;
m7, comparing the residual concentration of the corrosion inhibitor on 9 pre-film pipelines, and evaluating the durability of the corrosion inhibitor;
(3) the corrosion inhibitor corrosion prevention effect evaluation test comprises the following specific steps:
n1, zeroing the temperature sensor 5 and the pressure sensor 6 on the test loop;
n2, weighing 3 pipelines to be pre-coated to the accuracy of 0.1g, and pre-coating the 3 pipelines to be pre-coated according to the corrosion inhibitor pre-coating operation steps;
n3, assembling 3 pre-film pipelines on the second test module 151, wherein each pre-film pipeline is connected with the test loop through a flange 15;
n4, installing a corrosion hanging sheet 8 and a resistance probe 9 on the control group test area 7;
n5, opening the acid gas inlet valve 4, the first test gas inlet valve 16, the first test gas outlet valve 19 and the acid natural gas outlet valve 28; closing the first fuel gas inlet valve 3, the second test gas inlet valve 17, the third test gas inlet valve 18, the second test gas outlet valve 20, the third test gas outlet valve 21, the first fuel gas purging valve 22, the second fuel gas purging valve 23, the third fuel gas purging valve 24, the fourth fuel gas purging valve 25 and the fifth fuel gas purging valve 26;
n6, repeating the steps S6 and S7;
n7, purging the test device according to the third purging flow;
n8, repeating the step S9;
n9, disassembling 3 pre-film pipelines assembled on the second testing module 151, loading and transporting to a laboratory, and processing according to the corrosion rate detection step;
n10, comparing the corrosion rates of the pipelines arranged on the pre-coated pipeline and the control group test area 7, and evaluating the corrosion prevention effect of the corrosion inhibitor;
(4) the research test of the compatibility of the corrosion inhibitor and the methanol comprises the following specific steps:
h1, zeroing the temperature sensor 5 and the pressure sensor 6 on the test loop;
h2, weighing 6 pipelines to be pre-coated to the accuracy of 0.1g, and pre-coating the 6 pipelines to be pre-coated according to the corrosion inhibitor pre-coating operation steps;
h3, assembling 3 pre-film pipelines on the first test module 150, and assembling the other 3 pre-film pipelines on the third test module 152, wherein each pre-film pipeline is connected with the test loop through a flange 15;
h4, installing a corrosion hanging sheet 8 and a resistance probe 9 on the control group test area 7;
h5, opening the acid gas inlet valve 4, the second test gas inlet valve 17, the second test gas outlet valve 20 and the acid natural gas outlet valve 28, closing the first fuel gas inlet valve 3, the first test gas inlet valve 16, the third test gas inlet valve 18, the first test gas outlet valve 19, the third test gas outlet valve 21, the first fuel gas purge valve 22, the second fuel gas purge valve 23, the third fuel gas purge valve 24, the fourth fuel gas purge valve 25 and the fifth fuel gas purge valve 26;
h6, after the test is carried out for 10d, purging the first test module 150 according to a second purging process, detaching the first pre-film pipeline 141, the second pre-film pipeline 142 and the third pre-film pipeline 143 after purging is finished, loading and transporting to a laboratory, and processing according to the corrosion rate detection step;
h7, opening the acid gas inlet valve 4, the third test gas inlet valve 18, the third test gas outlet valve 21 and the acid natural gas outlet valve 28, closing the first fuel gas inlet valve 3, the first test gas inlet valve 16, the second test gas inlet valve 17, the first test gas outlet valve 19, the second test gas outlet valve 20, the first fuel gas purge valve 22, the second fuel gas purge valve 23, the third fuel gas purge valve 24, the fourth fuel gas purge valve 25 and the fifth fuel gas purge valve 26;
h8, using a methanol filling skid 13 to fill a proper amount of methanol into the test loop through a methanol filling point 11;
h9, after the test is carried out for 10d, purging the third test module 152 according to a fourth purging flow, detaching the seventh pre-film pipeline 147, the eighth pre-film pipeline 148 and the ninth pre-film pipeline 149 after the purging is finished, loading and transporting the materials to a laboratory, and processing the materials according to the corrosion rate detection step;
h10, comparing the corrosion rates and the corrosion inhibitor residual amounts of the first pre-film pipeline 141, the second pre-film pipeline 142, the third pre-film pipeline 143, the seventh pre-film pipeline 147, the eighth pre-film pipeline 148 and the ninth pre-film pipeline 149, and evaluating the compatibility of the corrosion inhibitor and the methanol.
Further, the first purging process comprises: and opening a first fuel gas inlet valve 3, a second test gas inlet valve 17, a third test gas inlet valve 18, a second test gas outlet valve 20 and a third test gas outlet valve 21, and allowing pilot fuel gas to enter the test loop from the fuel gas pipeline 2.
Further, the second purging process comprises: and opening the third fuel gas purge valve 24 and the first fuel gas purge valve 22, and closing the second fuel gas purge valve 23, the fourth fuel gas purge valve 25 and the fifth fuel gas purge valve 26.
Further, the third purging process comprises: the fourth fuel gas purge valve 25 is opened, the first fuel gas purge valve 22 is closed, and the second fuel gas purge valve 23, the third fuel gas purge valve 24, and the fifth fuel gas purge valve 26 are closed.
Further, the fourth purging process comprises: and opening the second fuel gas purge valve 23 and the fifth fuel gas purge valve 26, and closing the first fuel gas purge valve 22, the third fuel gas purge valve 24 and the fourth fuel gas purge valve 25.
Further, the method for analyzing the residual concentration of the corrosion inhibitor comprises the following steps: rapid detection equipment, ultraviolet spectrophotometer, visible spectrophotometer.
Further, the corrosion rate detection step is as follows:
(1) washing the inner wall of the pre-membrane pipeline after the test by using dichloromethane solution;
(2) collecting the dichloromethane solution after cleaning by using a collecting cylinder;
(3) putting the collecting cylinder containing the dichloromethane solution into a rotary evaporator to remove the dichloromethane in the solution;
(4) putting the solution without the dichloromethane on an aluminum tray weighed in advance, putting the aluminum tray into a vacuum oven at 55 ℃, drying, and weighing the aluminum tray again to obtain the weight difference which is the residual corrosion inhibitor amount after the pre-filming pipeline inner wall test;
(5) the dried pre-coated line was weighed to the nearest 0.1g and the corrosion rate was calculated.
Further, the prefilming system 30 includes: the corrosion inhibitor pre-filming device comprises a receiving device 301, a cable 302, a fixed pulley 303, a residual corrosion inhibitor discharging valve 304, a residual corrosion inhibitor discharging port 305, a residual corrosion inhibitor collector 306, a rear valve 307, a connecting flange 308, a first pre-filming region 309, a second pre-filming region 310, a third pre-filming region 311, a front valve 312, a control system 313, a sending device 314, a pre-filming device 315, an air outlet 316, a corrosion inhibitor filling port 317, a corrosion inhibitor overflow port 318 and a pipeline to be pre-filmed 319; the device comprises a receiving device 301, a rear valve 307, a first pre-film area 309, a second pre-film area 310, a third pre-film area 311, a front valve 312 and a sending device 314 which are sequentially connected, wherein 3 pre-film areas are connected through a connecting flange 308, a discharge valve 304 is connected with the receiving device 301 and a residual corrosion inhibitor collector 306, a fixed pulley 303 is arranged at the tail parts of the receiving device 301 and the sending device 314, a control system 313 bypasses the fixed pulley 303 through a cable 302 to be connected with the pre-film device 315, and an air outlet 316, a corrosion inhibitor filling port 317 and a corrosion inhibitor overflow port 318 are arranged on the sending device 314.
Further, the prefilming device 315 is disposed in the sending device 314, and includes: the corrosion inhibitor is characterized by comprising a fixed shaft 320, a spring 321, a permanent strong magnet 322, a corrosion inhibitor 323, a guide ball 324, a sliding ball 325 and a fixed ball 326, wherein the guide ball 324 and the fixed ball 326 are installed at two ends of 3 fixed shafts 320, the spring 321 is wound on the 3 fixed shafts 320, the right end of the spring 321 is fixed on the fixed ball 326, the left end of the spring 321 is in a free state and is not fixed on the sliding ball 325, the sliding ball 325 can slide on the 3 fixed shafts 320, the corrosion inhibitor 323 is added between the guide ball 324 and the sliding ball 325, the permanent strong magnet 322 is installed on the guide ball 324, the sliding ball 325 and the fixed ball 326, the N pole of the permanent strong magnet 322 installed on the guide ball 324 is towards the left, the S pole is towards the right, the N pole of the permanent strong magnet 322 installed on the sliding ball 325 is towards the left, the S pole is towards the right, and the S pole of. The corrosion inhibitor pre-film operation steps are as follows:
(1) designing and connecting a pre-film system 30;
(2) installing 3 pipelines to be pre-filmed in a first pre-film area 309, a second pre-film area 310 and a third pre-film area 311;
(3) placing the prefilming device 315 inside the sending device 314;
(4) opening a corrosion inhibitor filling port 317, and filling a corrosion inhibitor between a guide ball 324 and a sliding ball 325 of the pre-filming device 315;
(5) slowly opening the corrosion inhibitor overflow port 318, discharging air between the corrosion inhibitor and the sending device 314 in the pre-filming device 315, and compressing the spring 321;
(6) opening the front valve 312 and the rear valve 307;
(7) pulling the cable 302 through a control system 313 to enable the pre-filming device 315 to move in the pipeline 319 to be pre-filmed, and controlling the speed of the pre-filming device 315 to be 1-2 m/s;
(8) under the action of the attractive force of the permanent strong magnet 322 arranged on the guide ball 324 and the sliding ball 325, the repulsive force of the permanent strong magnet 322 arranged on the sliding ball 325 and the fixed ball 326, the elastic force of the spring 321 and the pulling force of the cable 302, the corrosion inhibitor between the guide ball 324 and the sliding ball 325 is maintained in a state of fully contacting with the pipeline 319 to be pre-coated, so as to ensure the film forming thickness of the corrosion inhibitor on the top of the pipeline 319 to be pre-coated;
(9) receiving the prefilming device 315 using the receiving device 301;
(10) opening the residual corrosion inhibitor drain valve 304 to allow the residual corrosion inhibitor to flow into the residual corrosion inhibitor collector 306 through the residual corrosion inhibitor drain 305;
(11) the pipeline 319 to be pre-coated, which is installed in the first pre-membrane area 309, the second pre-membrane area 310 and the third pre-membrane area 311, is detached and is ready to be assembled in the corrosion test area 14 for testing.
The invention has the beneficial effects that:
(1) by designing the corrosion inhibitor optimization and corrosion prevention effect evaluation test device, tests such as corrosion inhibitor optimization, corrosion inhibitor film durability evaluation, corrosion inhibitor corrosion prevention effect evaluation, corrosion inhibitor and methanol compatibility research can be carried out, corrosion inhibition efficiency, film durability and methanol compatibility of the corrosion inhibitor can be researched through tests, the corrosion inhibitor is optimized, and pipeline corrosion prevention effect is improved.
(2) A pre-film system is designed, so that a pre-film pipeline can be provided for a corrosion test area through the system, and a means is provided for experimental research on the durability of the corrosion inhibitor film and the corrosion prevention effect of the corrosion inhibitor.
(3) The pre-filming device is designed to enable the corrosion inhibitor to be in full contact with the top of the pipeline to be pre-filmed under the action of the permanent strong magnet, the spring elasticity and the cable tension, so that the thickness of the corrosion inhibitor film on the top is prevented from being too low, and the uniformity of the corrosion inhibitor film on the inner surface of the pre-filmed pipeline is ensured.
(4) And designing a corrosion rate detection method, and evaluating the corrosion inhibition effect of the corrosion inhibitor by combining a weight loss method and a dichloromethane solution cleaning method.
Drawings
FIG. 1 is a schematic view of a loop test apparatus according to an embodiment of the present invention.
FIG. 2 is a schematic diagram of a prefilming system in accordance with an embodiment of the present invention.
FIG. 3 is a schematic view of the start of coating by the prefilming device in accordance with one embodiment of the invention.
FIG. 4 is a schematic diagram of a film coating process of the prefilming device in accordance with the present invention.
FIG. 5 is a schematic view of a prefilming device A-A according to an embodiment of the invention.
The following description of specific embodiments of the present invention is provided in order to better understand the present invention with reference to the accompanying drawings.
Examples
As shown in fig. 1, a test apparatus for optimizing corrosion inhibitor and evaluating corrosion protection effect includes: an acid natural gas pipeline 1, a fuel gas pipeline 2, a first fuel gas inlet valve 3, an acid gas inlet valve 4, a temperature sensor 5, a pressure sensor 6, a control group test area 7, a corrosion coupon 8, a resistance probe 9, a corrosion inhibitor filling point 10, a methanol filling point 11, a corrosion inhibitor filling pry 12, a methanol filling pry 13, a corrosion test area 14, a flange 15, a first test gas inlet valve 16, a second test gas inlet valve 17, a third test gas inlet valve 18, a first test gas outlet valve 19, a second test gas outlet valve 20, a third test gas outlet valve 21, a first fuel gas purging valve 22, a second fuel gas purging valve 23, a third fuel gas purging valve 24, a fourth fuel gas purging valve 25, a fifth fuel gas purging valve 26, a gas-water separator 27, an acid natural gas outlet valve 28, a liquid taking device 29, a pre-membrane system 30 and a pre-membrane device 315;
the first fuel gas inlet valve 3 and the acid gas inlet valve 4 are connected with the acid natural gas pipeline 1 and the fuel gas pipeline 2, the temperature sensor 5 and the pressure sensor 6 are symmetrically distributed on a test loop, the comparison group test area 7 is arranged at the inlet of the loop, the corrosion hanging sheet 8 and the resistance probe 9 are arranged on the comparison group test area 7 to monitor the corrosion rate of the pipeline, the corrosion inhibitor filling point 10 and the methanol filling point 11 are respectively connected with the corrosion inhibitor filling pry 12 and the methanol filling pry 13, the corrosion test area 14 and the gas-water separator 27 are sequentially connected, and the acid natural gas outlet valve 28 and the liquid taking device 29 are connected with the gas-water separator 27.
The corrosion test zone 14 includes: a first test module 150, a second test module 151, a third test module 152, a first pre-membrane line 141, a second pre-membrane line 142, a third pre-membrane line 143, a fourth pre-membrane line 144, a fifth pre-membrane line 145, a sixth pre-membrane line 146, a seventh pre-membrane line 147, an eighth pre-membrane line 148, a ninth pre-membrane line 149; the first pre-membrane pipeline 141, the second pre-membrane pipeline 142 and the third pre-membrane pipeline 143 are assembled in a first test module 150, the fourth pre-membrane pipeline 144, the fifth pre-membrane pipeline 145 and the sixth pre-membrane pipeline 146 are assembled in a second test module 151, the seventh pre-membrane pipeline 147, the eighth pre-membrane pipeline 148 and the ninth pre-membrane pipeline 149 are assembled in a third test module 152, 9 pre-membrane pipelines are connected with a test loop through a flange 15, and 9 pre-membrane pipelines are pre-membrane through the pre-membrane system 30.
The tests which can be carried out by the corrosion inhibitor optimization and corrosion prevention effect evaluation test device comprise: the corrosion inhibitor optimizing test, the corrosion inhibitor film durability evaluation test, the corrosion inhibitor anticorrosion effect evaluation test and the corrosion inhibitor and methanol compatibility research test are characterized in that the specific steps of the tests are respectively as follows:
(1) the corrosion inhibitor optimization test comprises the following specific steps:
s1, connecting a testing device, removing sundries in a testing loop, checking the sealing property between pipe sections, ensuring that no leakage exists between a pipeline and a valve, and zeroing the temperature sensor 5 and the pressure sensor 6;
s2, designing and connecting a pre-membrane system 30, weighing 9 pipelines to be pre-membrane to be accurate to 0.1g, pre-membrane the 9 pipelines to be pre-membrane according to the corrosion inhibitor pre-membrane operation steps, wherein the first pre-membrane pipeline 141, the second pre-membrane pipeline 142 and the third pre-membrane pipeline 143 use (A) type corrosion inhibitor pre-membrane, the fourth pre-membrane pipeline 144, the fifth pre-membrane pipeline 145 and the sixth pre-membrane pipeline 146 use (B) type corrosion inhibitor pre-membrane, and the seventh pre-membrane pipeline 147, the eighth pre-membrane pipeline 148 and the ninth pre-membrane pipeline 149 use (C) type corrosion inhibitor pre-membrane;
s3, assembling 9 pre-film pipelines on the corrosion test area 14, wherein each pre-film pipeline is connected with the test loop through a flange 15;
s4, installing a corrosion hanging sheet 8 and a resistance probe 9 on the control group test area 7;
s5, opening the acid gas inlet valve 4, the first test gas inlet valve 16, the second test gas inlet valve 17, the third test gas inlet valve 18, the first test gas outlet valve 19, the second test gas outlet valve 20, the third test gas outlet valve 21 and the acid natural gas outlet valve 28; closing the first fuel gas inlet valve 3, the first fuel gas purging valve 22, the second fuel gas purging valve 23, the third fuel gas purging valve 24, the fourth fuel gas purging valve 25 and the fifth fuel gas purging valve 26;
s6, recording readings of a corrosion hanging sheet 8 and a resistance probe 9 on the control group test area 7 in the test process, and monitoring the corrosion rate of the pipeline on the control group test area 7; taking liquid from the liquid taking device 29 at regular time, and detecting the residual concentration of the corrosion inhibitor by using a corrosion inhibitor residual concentration analysis method;
s7, performing the test for 10-60 d, and closing the acid gas inlet valve 4;
s8, purging the test device according to the first purging process;
s9, after purging for 1h, detecting the concentration and the oxygen content of hydrogen sulfide by using a multifunctional gas monitor at a large-range pressure gauge vent port, closing the first fuel gas inlet valve 3 when the content of hydrogen sulfide is lower than 20ppm and the content of oxygen is lower than 2%, and stopping purging;
s10, disassembling 9 pre-film pipelines assembled on the corrosion test area 14, loading and transporting to a laboratory, and processing according to the corrosion rate detection step;
s11, selecting 9 pre-film pipelines with low corrosion rate and large residual corrosion inhibitor amount, and preferably selecting a corrosion inhibitor with better corrosion inhibition effect;
(2) the corrosion inhibitor film durability evaluation test comprises the following specific steps:
m1, zeroing the temperature sensor 5 and the pressure sensor 6 on the test loop;
m2, weighing 9 pipelines to be pre-coated to the accuracy of 0.1g, and pre-coating the 9 pipelines to be pre-coated according to the corrosion inhibitor pre-coating operation steps;
m3, repeating the steps S3-S6;
m4, after the test is carried out for 10d, purging the first test module 150 according to a second purging process, detaching the first pre-film pipeline 141, the second pre-film pipeline 142 and the third pre-film pipeline 143 after purging is finished, loading and transporting to a laboratory, and processing according to the corrosion rate detection step;
m5, after the test is carried out for 20d, purging the second test module 151 according to a third purging process, detaching the fourth pre-film pipeline 144, the fifth pre-film pipeline 145 and the sixth pre-film pipeline 146 after purging is finished, loading and transporting the products to a laboratory, and processing the products according to the corrosion rate detection step;
m6, after the test is carried out for 30d, purging the third test module 152 according to a fourth purging flow, detaching the seventh pre-film pipeline 147, the eighth pre-film pipeline 148 and the ninth pre-film pipeline 149 after the purging is finished, loading and transporting the materials to a laboratory, and processing the materials according to the corrosion rate detection step;
m7, comparing the residual concentration of the corrosion inhibitor on 9 pre-film pipelines, and evaluating the durability of the corrosion inhibitor;
(3) the corrosion inhibitor corrosion prevention effect evaluation test comprises the following specific steps:
n1, zeroing the temperature sensor 5 and the pressure sensor 6 on the test loop;
n2, weighing 3 pipelines to be pre-coated to the accuracy of 0.1g, and pre-coating the 3 pipelines to be pre-coated according to the corrosion inhibitor pre-coating operation steps;
n3, assembling 3 pre-film pipelines on the second test module 151, wherein each pre-film pipeline is connected with the test loop through a flange 15;
n4, installing a corrosion hanging sheet 8 and a resistance probe 9 on the control group test area 7;
n5, opening the acid gas inlet valve 4, the first test gas inlet valve 16, the first test gas outlet valve 19 and the acid natural gas outlet valve 28; closing the first fuel gas inlet valve 3, the second test gas inlet valve 17, the third test gas inlet valve 18, the second test gas outlet valve 20, the third test gas outlet valve 21, the first fuel gas purging valve 22, the second fuel gas purging valve 23, the third fuel gas purging valve 24, the fourth fuel gas purging valve 25 and the fifth fuel gas purging valve 26;
n6, repeating the steps S6 and S7;
n7, purging the test device according to the third purging flow;
n8, repeating the step S9;
n9, disassembling 3 pre-film pipelines assembled on the second testing module 151, loading and transporting to a laboratory, and processing according to the corrosion rate detection step;
n10, comparing the corrosion rates of the pipelines arranged on the pre-coated pipeline and the control group test area 7, and evaluating the corrosion prevention effect of the corrosion inhibitor;
(4) the research test of the compatibility of the corrosion inhibitor and the methanol comprises the following specific steps:
h1, zeroing the temperature sensor 5 and the pressure sensor 6 on the test loop;
h2, weighing 6 pipelines to be pre-coated to the accuracy of 0.1g, and pre-coating the 6 pipelines to be pre-coated according to the corrosion inhibitor pre-coating operation steps;
h3, assembling 3 pre-film pipelines on the first test module 150, and assembling the other 3 pre-film pipelines on the third test module 152, wherein each pre-film pipeline is connected with the test loop through a flange 15;
h4, installing a corrosion hanging sheet 8 and a resistance probe 9 on the control group test area 7;
h5, opening the acid gas inlet valve 4, the second test gas inlet valve 17, the second test gas outlet valve 20 and the acid natural gas outlet valve 28, closing the first fuel gas inlet valve 3, the first test gas inlet valve 16, the third test gas inlet valve 18, the first test gas outlet valve 19, the third test gas outlet valve 21, the first fuel gas purge valve 22, the second fuel gas purge valve 23, the third fuel gas purge valve 24, the fourth fuel gas purge valve 25 and the fifth fuel gas purge valve 26;
h6, after the test is carried out for 10d, purging the first test module 150 according to a second purging process, detaching the first pre-film pipeline 141, the second pre-film pipeline 142 and the third pre-film pipeline 143 after purging is finished, loading and transporting to a laboratory, and processing according to the corrosion rate detection step;
h7, opening the acid gas inlet valve 4, the third test gas inlet valve 18, the third test gas outlet valve 21 and the acid natural gas outlet valve 28, closing the first fuel gas inlet valve 3, the first test gas inlet valve 16, the second test gas inlet valve 17, the first test gas outlet valve 19, the second test gas outlet valve 20, the first fuel gas purge valve 22, the second fuel gas purge valve 23, the third fuel gas purge valve 24, the fourth fuel gas purge valve 25 and the fifth fuel gas purge valve 26;
h8, using a methanol filling skid 13 to fill a proper amount of methanol into the test loop through a methanol filling point 11;
h9, after the test is carried out for 10d, purging the third test module 152 according to a fourth purging flow, detaching the seventh pre-film pipeline 147, the eighth pre-film pipeline 148 and the ninth pre-film pipeline 149 after the purging is finished, loading and transporting the materials to a laboratory, and processing the materials according to the corrosion rate detection step;
h10, comparing the corrosion rates and the corrosion inhibitor residual amounts of the first pre-film pipeline 141, the second pre-film pipeline 142, the third pre-film pipeline 143, the seventh pre-film pipeline 147, the eighth pre-film pipeline 148 and the ninth pre-film pipeline 149, and evaluating the compatibility of the corrosion inhibitor and the methanol.
The first purging process comprises the following steps: opening a first fuel gas inlet valve 3, a second test gas inlet valve 17, a third test gas inlet valve 18, a second test gas outlet valve 20 and a third test gas outlet valve 21, and introducing pilot fuel gas into a test loop from a fuel gas pipeline 2; the second purging process comprises the following steps: opening a third fuel gas purging valve 24 and a first fuel gas purging valve 22, and closing a second fuel gas purging valve 23, a fourth fuel gas purging valve 25 and a fifth fuel gas purging valve 26; the third purging process comprises the following steps: opening a fourth fuel gas purge valve 25, closing the first fuel gas purge valve 22, and closing the second fuel gas purge valve 23, the third fuel gas purge valve 24, and the fifth fuel gas purge valve 26; the fourth purging process comprises the following steps: and opening the second fuel gas purge valve 23 and the fifth fuel gas purge valve 26, and closing the first fuel gas purge valve 22, the third fuel gas purge valve 24 and the fourth fuel gas purge valve 25.
The method for analyzing the residual concentration of the corrosion inhibitor comprises the following steps: rapid detection equipment, ultraviolet spectrophotometer, visible spectrophotometer.
The corrosion rate detection step comprises:
(1) washing the inner wall of the pre-membrane pipeline after the test by using dichloromethane solution;
(2) collecting the dichloromethane solution after cleaning by using a collecting cylinder;
(3) putting the collecting cylinder containing the dichloromethane solution into a rotary evaporator to remove the dichloromethane in the solution;
(4) putting the solution without the dichloromethane on an aluminum tray weighed in advance, putting the aluminum tray into a vacuum oven at 55 ℃, drying, and weighing the aluminum tray again to obtain the weight difference which is the residual corrosion inhibitor amount after the pre-filming pipeline inner wall test;
(5) the dried pre-coated line was weighed to the nearest 0.1g and the corrosion rate was calculated.
As shown in fig. 2, 3, 4, and 5, the prefilming system 30 includes: the corrosion inhibitor pre-filming device comprises a receiving device 301, a cable 302, a fixed pulley 303, a residual corrosion inhibitor discharging valve 304, a residual corrosion inhibitor discharging port 305, a residual corrosion inhibitor collector 306, a rear valve 307, a connecting flange 308, a first pre-filming region 309, a second pre-filming region 310, a third pre-filming region 311, a front valve 312, a control system 313, a sending device 314, a pre-filming device 315, an air outlet 316, a corrosion inhibitor filling port 317, a corrosion inhibitor overflow port 318 and a pipeline to be pre-filmed 319; the device comprises a receiving device 301, a rear valve 307, a first pre-film area 309, a second pre-film area 310, a third pre-film area 311, a front valve 312 and a sending device 314 which are sequentially connected, wherein 3 pre-film areas are connected through a connecting flange 308, a discharge valve 304 is connected with the receiving device 301 and a residual corrosion inhibitor collector 306, a fixed pulley 303 is arranged at the tail parts of the receiving device 301 and the sending device 314, a control system 313 bypasses the fixed pulley 303 through a cable 302 to be connected with the pre-film device 315, and an air outlet 316, a corrosion inhibitor filling port 317 and a corrosion inhibitor overflow port 318 are arranged on the sending device 314.
The prefilming device 315 is placed inside the sending device 314, and is characterized in that it comprises: the corrosion inhibitor is characterized by comprising a fixed shaft 320, a spring 321, a permanent strong magnet 322, a corrosion inhibitor 323, a guide ball 324, a sliding ball 325 and a fixed ball 326, wherein the guide ball 324 and the fixed ball 326 are installed at two ends of 3 fixed shafts 320, the spring 321 is wound on the 3 fixed shafts 320, the right end of the spring 321 is fixed on the fixed ball 326, the left end of the spring 321 is in a free state and is not fixed on the sliding ball 325, the sliding ball 325 can slide on the 3 fixed shafts 320, the corrosion inhibitor 323 is added between the guide ball 324 and the sliding ball 325, the permanent strong magnet 322 is installed on the guide ball 324, the sliding ball 325 and the fixed ball 326, the N pole of the permanent strong magnet 322 installed on the guide ball 324 is towards the left, the S pole is towards the right, the N pole of the permanent strong magnet 322 installed on the sliding ball 325 is towards the left, the S pole is towards the right, and the S pole of. The corrosion inhibitor pre-film operation steps are as follows:
(1) designing and connecting a pre-film system 30;
(2) installing 3 pipelines to be pre-filmed in a first pre-film area 309, a second pre-film area 310 and a third pre-film area 311;
(3) placing the prefilming device 315 inside the sending device 314;
(4) opening a corrosion inhibitor filling port 317, and filling a corrosion inhibitor between a guide ball 324 and a sliding ball 325 of the pre-filming device 315;
(5) slowly opening the corrosion inhibitor overflow port 318, discharging air between the corrosion inhibitor and the sending device 314 in the pre-filming device 315, and compressing the spring 321;
(6) opening the front valve 312 and the rear valve 307;
(7) pulling the cable 302 through a control system 313 to enable the pre-filming device 315 to move in the pipeline 319 to be pre-filmed, and controlling the speed of the pre-filming device 315 to be 1-2 m/s;
(8) under the action of the attractive force of the permanent strong magnet 322 arranged on the guide ball 324 and the sliding ball 325, the repulsive force of the permanent strong magnet 322 arranged on the sliding ball 325 and the fixed ball 326, the elastic force of the spring 321 and the pulling force of the cable 302, the corrosion inhibitor between the guide ball 324 and the sliding ball 325 is maintained in a state of fully contacting with the pipeline 319 to be pre-coated, so as to ensure the film forming thickness of the corrosion inhibitor on the top of the pipeline 319 to be pre-coated;
(9) receiving the prefilming device 315 using the receiving device 301;
(10) opening the residual corrosion inhibitor drain valve 304 to allow the residual corrosion inhibitor to flow into the residual corrosion inhibitor collector 306 through the residual corrosion inhibitor drain 305;
(11) the pipeline 319 to be pre-coated, which is installed in the first pre-membrane area 309, the second pre-membrane area 310 and the third pre-membrane area 311, is detached and is ready to be assembled in the corrosion test area 14 for testing.
The foregoing is a preferred embodiment of the present invention, and it should be noted that it would be apparent to those skilled in the art that various modifications and enhancements can be made without departing from the principles of the invention, and such modifications and enhancements are also considered to be within the scope of the invention.
Claims (4)
1. A corrosion inhibitor optimization and corrosion prevention effect evaluation test method adopts a test device which comprises the following steps: the corrosion testing device comprises an acidic natural gas pipeline (1), a fuel gas pipeline (2), a first fuel gas inlet valve (3), an acid gas inlet valve (4), a temperature sensor (5), a pressure sensor (6), a control group testing area (7), a corrosion hanging sheet (8), a resistance probe (9), a corrosion inhibitor filling point (10), a methanol filling point (11), a corrosion inhibitor filling pry (12), a methanol filling pry (13), a corrosion testing area (14), a flange (15), a first test gas inlet valve (16), a second test gas inlet valve (17), a third test gas inlet valve (18), a first test gas outlet valve (19), a second test gas outlet valve (20), a third test gas outlet valve (21), a first fuel gas purging valve (22), a second fuel gas purging valve (23), a third fuel gas purging valve (24), a fourth fuel gas purging valve (25), A fifth fuel gas purge valve (26), a gas-water separator (27), an acid natural gas outlet valve (28), a liquid taking device (29), a pre-membrane system (30) and a pre-membrane device (315);
the corrosion testing device is characterized in that the first fuel gas inlet valve (3) is connected with a fuel gas pipeline (2), the acid gas inlet valve (4) is connected with the acid natural gas pipeline (1), the temperature sensor (5) and the pressure sensor (6) are symmetrically distributed on a testing loop, the comparison group testing area (7) is arranged at the inlet of the loop, the corrosion hanging sheet (8) and the resistance probe (9) are installed on the comparison group testing area (7) to monitor the corrosion rate of the pipeline, the corrosion inhibitor filling point (10) and the methanol filling point (11) are respectively connected with the corrosion inhibitor filling pry (12) and the methanol filling pry (13), the corrosion testing area (14) and the gas-water separator (27) are sequentially connected, and the acid natural gas outlet valve (28) and the liquid taking device (29) are connected with the gas-water separator (27);
the corrosion test zone (14) comprises: a first test module (150), a second test module (151), a third test module (152), a first pre-membrane pipeline (141), a second pre-membrane pipeline (142), a third pre-membrane pipeline (143), a fourth pre-membrane pipeline (144), a fifth pre-membrane pipeline (145), a sixth pre-membrane pipeline (146), a seventh pre-membrane pipeline (147), an eighth pre-membrane pipeline (148) and a ninth pre-membrane pipeline (149); the first pre-membrane pipeline (141), the second pre-membrane pipeline (142) and the third pre-membrane pipeline (143) are assembled in a first test module (150), the fourth pre-membrane pipeline (144), the fifth pre-membrane pipeline (145) and the sixth pre-membrane pipeline (146) are assembled in a second test module (151), the seventh pre-membrane pipeline (147), the eighth pre-membrane pipeline (148) and the ninth pre-membrane pipeline (149) are assembled in a third test module (152), the 9 pre-membrane pipelines are connected with a test loop through the flange (15), and the 9 pre-membrane pipelines are pre-membrane by the pre-membrane device (315) through the pre-membrane system (30);
the tests that can be carried out by the test circuit include: the corrosion inhibitor optimizing test, the corrosion inhibitor film durability evaluation test, the corrosion inhibitor anticorrosion effect evaluation test and the corrosion inhibitor and methanol compatibility research test are characterized in that the test comprises the following concrete steps:
(1) the corrosion inhibitor optimization test comprises the following specific steps:
s1, connecting a test device, removing sundries in a test loop, checking the sealing property between pipe sections, ensuring that no leakage exists between a pipeline and a valve, and zeroing a temperature sensor (5) and a pressure sensor (6);
s2, designing and connecting a pre-membrane system (30), weighing 9 pipelines to be pre-membrane to be accurate to 0.1g, pre-membrane the 9 pipelines to be pre-membrane according to the corrosion inhibitor pre-membrane operation steps, wherein a type (A) corrosion inhibitor pre-membrane is used for a first pre-membrane pipeline (141), a second pre-membrane pipeline (142) and a third pre-membrane pipeline (143), a type (B) corrosion inhibitor pre-membrane is used for a fourth pre-membrane pipeline (144), a fifth pre-membrane pipeline (145) and a sixth pre-membrane pipeline (146), and a type (C) corrosion inhibitor pre-membrane is used for a seventh pre-membrane pipeline (147), an eighth pre-membrane pipeline (148) and a ninth pre-membrane pipeline (149);
s3, assembling 9 pre-film pipelines on a corrosion test area (14), wherein each pre-film pipeline is connected with a test loop through a flange (15);
s4, installing a corrosion hanging sheet (8) and a resistance probe (9) on the control group test area (7);
s5, opening the acid gas inlet valve (4), the first test gas inlet valve (16), the second test gas inlet valve (17), the third test gas inlet valve (18), the first test gas outlet valve (19), the second test gas outlet valve (20), the third test gas outlet valve (21) and the acid natural gas outlet valve (28); closing a first fuel gas inlet valve (3), a first fuel gas purging valve (22), a second fuel gas purging valve (23), a third fuel gas purging valve (24), a fourth fuel gas purging valve (25) and a fifth fuel gas purging valve (26);
s6, recording readings of a corrosion hanging sheet (8) and a resistance probe (9) on the control group test area (7) in the test process, and monitoring the corrosion rate of the pipeline on the control group test area (7); taking liquid from a liquid taking device (29) at regular time, and detecting the residual concentration of the corrosion inhibitor by using a corrosion inhibitor residual concentration analysis method;
s7, carrying out the test for 10-60 d, and closing the acid gas inlet valve (4);
s8, purging the test device according to the first purging process;
s9, after purging for 1h, detecting the concentration and the oxygen content of hydrogen sulfide by using a multifunctional gas monitor at a large-range pressure gauge vent port, closing a first fuel gas inlet valve (3) when the content of hydrogen sulfide is lower than 20ppm and the content of oxygen is lower than 2%, and stopping purging;
s10, disassembling 9 pre-film pipelines assembled on the corrosion test area (14), loading and transporting to a laboratory, and processing according to the corrosion rate detection step;
s11, selecting 9 pre-film pipelines with low corrosion rate and large residual corrosion inhibitor amount, and preferably selecting a corrosion inhibitor with better corrosion inhibition effect; (2) the corrosion inhibitor film durability evaluation test comprises the following specific steps:
m1, zero setting of a temperature sensor (5) and a pressure sensor (6) on the test loop;
m2, weighing 9 pipelines to be pre-coated to the accuracy of 0.1g, and pre-coating the 9 pipelines to be pre-coated according to the corrosion inhibitor pre-coating operation steps;
m3, repeating the steps S3-S6;
m4, after the test is carried out for 10d, purging the first test module (150) according to a second purging process, detaching the first pre-membrane pipeline (141), the second pre-membrane pipeline (142) and the third pre-membrane pipeline (143) after purging is finished, loading and transporting the pre-membrane pipeline to a laboratory, and processing according to the corrosion rate detection step;
m5, after the test is carried out for 20d, purging the second testing module (151) according to a third purging process, detaching the fourth pre-film pipeline (144), the fifth pre-film pipeline (145) and the sixth pre-film pipeline (146) after purging is finished, loading and transporting the fourth pre-film pipeline, the fifth pre-film pipeline and the sixth pre-film pipeline to a laboratory, and processing according to the corrosion rate detection step;
m6, after the test is carried out for 30d, purging the third testing module (152) according to a fourth purging process, detaching a seventh pre-film pipeline (147), an eighth pre-film pipeline (148) and a ninth pre-film pipeline (149) after purging is finished, loading and transporting the materials to a laboratory, and processing according to the corrosion rate detection step;
m7, comparing the residual concentration of the corrosion inhibitor on 9 pre-film pipelines, and evaluating the durability of the corrosion inhibitor;
(3) the corrosion inhibitor corrosion prevention effect evaluation test comprises the following specific steps:
n1, zero setting of a temperature sensor (5) and a pressure sensor (6) on the test loop;
n2, weighing 3 pipelines to be pre-coated to the accuracy of 0.1g, and pre-coating the 3 pipelines to be pre-coated according to the corrosion inhibitor pre-coating operation steps;
n3, assembling 3 pre-film pipelines on a second test module (151), wherein each pre-film pipeline is connected with the test loop through a flange (15);
n4, installing a corrosion hanging sheet (8) and a resistance probe (9) on the control group test area (7);
n5, opening an acid gas inlet valve (4), a first test gas inlet valve (16), a first test gas outlet valve (19) and an acid natural gas outlet valve (28); closing a first fuel gas inlet valve (3), a second test gas inlet valve (17), a third test gas inlet valve (18), a second test gas outlet valve (20), a third test gas outlet valve (21), a first fuel gas purging valve (22), a second fuel gas purging valve (23), a third fuel gas purging valve (24), a fourth fuel gas purging valve (25) and a fifth fuel gas purging valve (26);
n6, repeating the steps S6 and S7;
n7, purging the test device according to the third purging flow;
n8, repeating the step S9;
n9, disassembling 3 pre-film pipelines assembled on the second testing module (151), loading and transporting to a laboratory, and processing according to the corrosion rate detection step;
n10, comparing the corrosion rates of pipelines arranged on the pre-coated pipeline and the control group test area (7) to evaluate the corrosion prevention effect of the corrosion inhibitor;
(4) the research test of the compatibility of the corrosion inhibitor and the methanol comprises the following specific steps:
h1, zero setting of a temperature sensor (5) and a pressure sensor (6) on the test loop;
h2, weighing 6 pipelines to be pre-coated to the accuracy of 0.1g, and pre-coating the 6 pipelines to be pre-coated according to the corrosion inhibitor pre-coating operation steps;
h3, assembling 3 pre-film pipelines on the first test module (150), and assembling the other 3 pre-film pipelines on the third test module (152), wherein each pre-film pipeline is connected with the test loop through a flange (15);
h4, installing a corrosion hanging sheet (8) and a resistance probe (9) on the control group test area (7);
h5, opening an acid gas inlet valve (4), a second test gas inlet valve (17), a second test gas outlet valve (20) and an acid natural gas outlet valve (28), closing a first fuel gas inlet valve (3), a first test gas inlet valve (16), a third test gas inlet valve (18), a first test gas outlet valve (19), a third test gas outlet valve (21), a first fuel gas purging valve (22), a second fuel gas purging valve (23), a third fuel gas purging valve (24), a fourth fuel gas purging valve (25) and a fifth fuel gas purging valve (26);
h6, after the test is carried out for 10d, purging the first test module (150) according to a second purging process, detaching the first pre-membrane pipeline (141), the second pre-membrane pipeline (142) and the third pre-membrane pipeline (143) after purging is finished, loading and transporting the pre-membrane pipeline to a laboratory, and processing according to the corrosion rate detection step;
h7, opening the acid gas inlet valve (4), the third test gas inlet valve (18), the third test gas outlet valve (21) and the acid natural gas outlet valve (28), closing the first fuel gas inlet valve (3), the first test gas inlet valve (16), the second test gas inlet valve (17), the first test gas outlet valve (19) and the second test gas outlet valve (19)4A gas outlet valve (20), a first fuel gas purging valve (22), a second fuel gas purging valve (23), a third fuel gas purging valve (24), a fourth fuel gas purging valve (25) and a fifth fuel gas purging valve (26);
h8, using a methanol filling skid (13) to fill a proper amount of methanol into the test loop through a methanol filling point (11);
h9, after the test is carried out for 10d, purging the third testing module (152) according to a fourth purging flow, detaching the seventh pre-film pipeline (147), the eighth pre-film pipeline (148) and the ninth pre-film pipeline (149) after purging is finished, loading and transporting the materials to a laboratory, and processing the materials according to the corrosion rate detection step;
h10, comparing the corrosion rates and the corrosion inhibitor residual amounts of the first pre-film pipeline (141), the second pre-film pipeline (142), the third pre-film pipeline (143), the seventh pre-film pipeline (147), the eighth pre-film pipeline (148) and the ninth pre-film pipeline (149), and evaluating the compatibility of the corrosion inhibitor and methanol;
the first purging process comprises the following steps: opening a first fuel gas inlet valve (3), a second test gas inlet valve (17), a third test gas inlet valve (18), a second test gas outlet valve (20) and a third test gas outlet valve (21), and allowing pilot fuel gas to enter a test loop from a fuel gas pipeline (2); the second purging process comprises the following steps: opening a third fuel gas purging valve (24) and a first fuel gas purging valve (22), and closing a second fuel gas purging valve (23), a fourth fuel gas purging valve (25) and a fifth fuel gas purging valve (26); the third purging process comprises the following steps: opening a fourth fuel gas purging valve (25), closing the first fuel gas purging valve (22), closing the second fuel gas purging valve (23), the third fuel gas purging valve (24) and the fifth fuel gas purging valve (26); the fourth purging process comprises the following steps: and opening the second fuel gas purging valve (23) and the fifth fuel gas purging valve (26), and closing the first fuel gas purging valve (22), the third fuel gas purging valve (24) and the fourth fuel gas purging valve (25).
2. The test method for optimizing corrosion inhibitor and evaluating corrosion prevention effect according to claim 1, wherein the corrosion inhibitor pre-filming operation comprises the following steps:
(1) designing, connecting a prefilming system (30), the prefilming system (30) comprising: the corrosion inhibitor automatic control device comprises a receiving device (301), a cable (302), a fixed pulley (303), a residual corrosion inhibitor discharge valve (304), a residual corrosion inhibitor discharge port (305), a residual corrosion inhibitor collector (306), a rear valve (307), a connecting flange (308), a first pre-membrane area (309), a second pre-membrane area (310), a third pre-membrane area (311), a front valve (312) and a control systemThe system (313), a sending device (314), a pre-filming device (315), an air outlet (316), a corrosion inhibitor filling port (317), a corrosion inhibitor overflow port (318) and a pipeline (319) to be pre-filmed; the receiving device (301), the rear valve (307), the first pre-membrane region (309), the second pre-membrane region (310), the third pre-membrane region (311), the front valve (312) and the sending device (314) are sequentially connected, the 3 pre-membrane regions are connected through a connecting flange (308), and the discharge valve (304)1The control system (313) bypasses the fixed pulley (303) through a cable (302) to be connected with a pre-filming device (315), and the air outlet (316), the corrosion inhibitor filling port (317) and the corrosion inhibitor overflow port (318) are arranged on the sending device (314);
(2) installing 3 pipelines to be pre-filmed on a first pre-film area (309), a second pre-film area (310) and a third pre-film area (311);
(3) placing a prefilming device (315) within a delivery device (314); the prefilming device (315) comprises: the corrosion inhibitor comprises a fixed shaft (320), a spring (321), a permanent strong magnet (322), a corrosion inhibitor (323), a guide ball (324), a sliding ball (325) and a fixed ball (326), wherein the guide ball (324) and the fixed ball (326) are installed at two ends of the 3 fixed shafts (320), the spring (321) is wound on the 3 fixed shafts (320), the right end of the spring (321) is fixed on the fixed ball (326), the left end of the spring is in a free state and is not fixed on the sliding ball (325), the sliding ball (325) can slide on the 3 fixed shafts (320), the corrosion inhibitor (323) is added between the guide ball (324) and the sliding ball (325), the permanent strong magnet (322) is installed on the guide ball (324), the sliding ball (325) and the fixed ball (326), the N pole of the permanent strong magnet (322) installed on the guide ball (324) faces left and the S pole faces right, the N pole of the permanent strong magnet (322) arranged on the sliding ball (325) is towards the left and the S pole is towards the right, and the S pole of the permanent strong magnet (322) arranged on the fixed ball (326) is towards the left and the N pole is towards the right;
(4) opening a corrosion inhibitor filling port (317), and filling a corrosion inhibitor between a guide ball (324) and a sliding ball (325) of a pre-filming device (315);
(5) slowly opening the corrosion inhibitor overflow port (318) to discharge air between the corrosion inhibitor and the sending device (314) in the pre-filming device (315), wherein the spring (321) is in a compressed state;
(6) opening a front valve (312) and a rear valve (307);
(7) pulling the cable (302) through a control system (313) to enable the pre-filming device (315) to move in the pipeline (319) to be pre-filmed, and controlling the speed of the pre-filming device (315) to be 1-2 m/s;
(8) under the action of attractive force of a permanent strong magnet (322) arranged on a guide ball (324) and a sliding ball (325), the action of repulsive force of the permanent strong magnet (322) arranged on the sliding ball (325) and a fixed ball (326), the elastic force of a spring (321) and the pulling force of a cable (302), the corrosion inhibitor between the guide ball (324) and the sliding ball (325) is maintained in a state of fully contacting with a pipeline (319) to be pre-coated, and the film forming thickness of the corrosion inhibitor on the top of the pipeline (319) to be pre-coated is ensured;
(9) receiving a prefilming device (315) using a receiving device (301);
(10) opening the residual corrosion inhibitor discharge valve (304) to allow the residual corrosion inhibitor to flow into the residual corrosion inhibitor collector (306) through the residual corrosion inhibitor discharge port (305);
(11) and (3) detaching the pipeline (319) to be pre-coated, which is arranged on the first pre-membrane area (309), the second pre-membrane area (310) and the third pre-membrane area (311), and preparing to be assembled in a corrosion test area (14) for testing.
3. The method for testing the optimization of the corrosion inhibitor and the evaluation of the corrosion protection effect according to claim 1, wherein the analysis method of the residual concentration of the corrosion inhibitor comprises the analysis of the residual concentration of the corrosion inhibitor by using an ultraviolet spectrophotometer or a visible spectrophotometer.
4. The corrosion inhibitor optimization and corrosion prevention effect evaluation test method according to claim 1, wherein the corrosion rate detection step comprises:
(1) cleaning the inner wall of the pre-membrane pipeline after the test by using a dichloromethane solution;
(2) collecting the dichloromethane solution after cleaning by using a collecting cylinder;
(3) putting the collecting cylinder containing the dichloromethane solution into a rotary evaporator to remove the dichloromethane in the solution;
(4) putting the solution without the dichloromethane on an aluminum tray weighed in advance, putting the aluminum tray into a vacuum oven at 55 ℃, drying, and weighing the aluminum tray again to obtain the weight difference which is the residual corrosion inhibitor amount after the pre-filming pipeline inner wall test;
(5) the dried pre-coated line was weighed to the nearest 0.1g and the corrosion rate was calculated.
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