CN211043067U - Sewage corrosion evaluation device - Google Patents
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- CN211043067U CN211043067U CN201921784968.2U CN201921784968U CN211043067U CN 211043067 U CN211043067 U CN 211043067U CN 201921784968 U CN201921784968 U CN 201921784968U CN 211043067 U CN211043067 U CN 211043067U
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Abstract
The utility model relates to a sewage corrosion evaluation device in the sewage corrosion monitoring devices technical field, include through the simulation pipeline and the circulation heating bucket that the circulation pipeline connects, be connected with circulating pump and check valve on the export of circulation heating bucket and the circulation pipeline of simulation pipeline import, the heating system of circulation heating bucket is connected with the temperature controller, be connected with at least one dismantled and assembled lacing film seat and probe joint on the pipe wall of simulation pipeline respectively. The utility model discloses a sewage corrosion evaluation device, circulation heating bucket are used for storing the sewage of on-the-spot extraction, and the simulation pipeline passes through circulating line and circulation heating bucket cyclic connection, can simulate on-the-spot sewage on-the-spot parameters such as pressure, velocity of flow and temperature and simulate circulation, and dismantled and assembled lacing film seat and the probe joint that set up on the simulation pipeline wall are used for the average corrosion rate of indoor simulation lacing film weightlessness method to detect and electrochemical method corrodes the short-term test respectively.
Description
Technical Field
The utility model relates to a sewage corrosion monitoring devices technical field, in particular to sewage corrosion evaluation device.
Background
Corrosion is a destructive attack of the metal by chemical or electrochemical reactions with the surrounding environment, and is a delicate phenomenon, particularly during contact between metal and water. The loss and harm caused by corrosion are huge, and in the aspect of direct loss, the cost of the protection technology and the maintenance, replacement and labor cost of the corroded equipment are adopted; in the aspect of indirect loss, shutdown and production stop caused by equipment corrosion, material loss caused by leakage, dripping and leakage, product pollution, quality reduction, equipment efficiency reduction and energy consumption increase caused by corrosion, equipment damage, casualty accidents and the like caused by corrosion. The corrosion can cause great direct or indirect economic loss, and reported that 1 ton of steel and iron are corroded into rust every 90 seconds all over the world, which brings huge waste, and according to incomplete statistics, the loss caused by corrosion of China in the whole industry in 2014 exceeds 2 trillion yuan; catastrophic and serious accidents can be caused, and the life safety is endangered.
The corrosion monitoring and detecting technology is to measure and investigate the corrosion rate and corrosion state of material and equipment by various technical means, determine the corrosion rate of the equipment, adjust the technological parameters and take corresponding precautionary measures, so as to prevent and control the occurrence and development of corrosion and enable the equipment to be in a good controllable running state.
The hanger weight loss method is characterized in that after a hanger is exposed in a corrosion medium for a period of time, the average corrosion rate is measured according to the weight loss or weight gain of the hanger, the method is simple, the uniform corrosion rate can be quantitatively measured, and the monitoring result of the hanger weight loss method is agreed by people, but the method only provides the average corrosion rate, cannot reflect the fluctuation state of the corrosion rate along with the change of anticorrosion measures, has an overlong detection period (generally requires about 7-30 days), and has a slow reaction speed to the change of the corrosion state.
The resistance probe method, the alternating current impedance method, the inductance method, the polarization curve method and the like all belong to electrochemical methods, a constant potential rectifier or an electrochemical testing instrument is adopted, the corrosion rate can be rapidly detected (several minutes to 3 days), data can be automatically collected, processed and stored, the result is visual, visual and accurate, the sensitivity is high, no pollution is caused, and the operation is simple. However, each method has its limitations, such as the need to artificially polish the working electrode off-line after each test by the polarization curve method; resistance probe method in the presence of H2S/CO2In an acidic medium of (2), corrosion products FeS/FeCO3May coat the probe sensor surface and have conductivity, causing the corrosion rate value to change even as opposed to actual. According to long-term sewage corrosion monitoring practices, a system and a device capable of simulating field operation conditions indoors for corrosion monitoring are lacked.
SUMMERY OF THE UTILITY MODEL
The utility model discloses to the drawback that exists in the use of various sewage corrosion monitoring devices among the prior art, provide a sewage corrosion evaluation device for indoor simulation test to comprehensive evaluation sewage corrosion's periodicity and the ageing state of different time.
The utility model aims at realizing like this, a sewage corrosion evaluation device, include through the simulation pipeline and the circulation heating bucket of circulation pipe connection, be connected with circulating pump and check valve on the export of circulation heating bucket and the circulation pipeline of simulation pipeline import, the heating system of circulation heating bucket is connected with the temperature controller, be connected with at least one dismantled and assembled lacing film seat and probe joint on the pipe wall of simulation pipeline respectively.
The utility model discloses a sewage corrosion evaluation device, circulation heating bucket are used for storing the sewage of on-the-spot extraction, and the simulation pipeline passes through circulating line and circulation heating bucket cyclic connection, can simulate on-the-spot sewage on-the-spot parameters such as pressure, velocity of flow and temperature and simulate circulation, and dismantled and assembled lacing film seat and the probe joint that set up on the simulation pipeline wall are used for the average corrosion rate of indoor simulation lacing film weightlessness method to detect and electrochemical method corrodes the short-term test respectively. Therefore, the utility model discloses a sewage corrosion evaluation device has following beneficial effect:
firstly, directly sampling a field corrosion medium as an experimental medium, and simulating parameters such as flow velocity, temperature and pressure of the field corrosion medium and the like influencing the field corrosion rate indoors, so that the method has more practical guiding significance for guiding field establishment of anticorrosion measures;
secondly, the electrochemical test method to be evaluated and the weightless hanging piece method run in the same simulation pipeline, parameters such as corrosion medium, temperature, flow rate and the like are consistent, and the evaluation result is more reasonable;
thirdly, in the simulation experiment process, the electrochemical method to be evaluated is tested on line, and is not required to be taken out for off-line testing, so that sampling test errors are eliminated, and the data is closer to the field pipeline corrosion data;
fourth, different electrochemical test probes can be mounted on the electrochemical probe mount, thereby enabling a variety of electrochemical corrosion tests to be performed.
In order to realize the quick replacement and installation of the hanging piece, the hanging piece seat comprises a joint seat connected with the pipe wall of the simulation pipeline, a through step hole is formed in the center of the joint seat, a hanging piece mechanism is inserted into the step hole in a sealed mode, and a pressing cap is connected between the hanging piece mechanism and the step hole in a threaded mode.
In order to ensure the sealing installation and connection of the hanging pieces, an upper hole section, a middle hole section and a lower hole section which gradually shrink from the outside of the barrel to the inside of the barrel are arranged in the step hole of the joint seat, internal threads matched with the periphery of the pressing cap are arranged in the upper hole section, and the inner periphery of the middle hole section is in sealing fit with the hanging piece mechanism; the center of the pressing cap is provided with a center hole, the hanging piece mechanism comprises an ejector rod in sliding fit with the center hole of the pressing cap, the lower side of the ejector rod is provided with a sealing section in sliding seal fit with the center hole section of the joint seat, the sealing section is provided with an annular sealing groove, and a sealing ring is arranged in the sealing groove; the lower side of the sealing section is provided with a hanging piece connecting rod, the lower portion of the hanging piece connecting rod is provided with a hanging piece mounting hole which is axially vertical to the hanging piece connecting rod, and the lateral sides of the hanging piece connecting rods on the two sides of the hanging piece mounting hole are provided with mounting planes which are convenient for hanging piece lamination.
Furthermore, the hanging piece mechanism is a double-hanging piece connecting mechanism, and the double-hanging pieces are respectively connected to two sides of the hanging piece mounting hole of the hanging piece connecting rod and fixed through pins.
In order to control the installation direction of the hanging pieces relative to the liquid flow, an indication line for indicating the installation direction of the hanging pieces is arranged on the top end face of the ejector rod of the hanging piece mechanism and passes through the central axis of the ejector rod.
The probe joint is a pipe joint fixedly connected with the circulating heating barrel, the lower end of the joint is connected with the wall of the circulating heating barrel, and an upper pipe orifice of the pipe joint is provided with an internal thread matched with the thread of the detection probe.
In order to ensure the stability of the temperature of the circulating system, the peripheries of the circulating heating barrel and the simulated pipeline are wrapped with heat-insulating layers; meanwhile, in order to facilitate the monitoring of the temperature and the pressure in the circulating system, a pressure gauge is connected to a circulating water pipe connected with the water outlet of the simulation pipeline; and a temperature sensor is arranged in the circulating heating barrel.
A drain outlet is arranged at the bottom of the circulating heating barrel for facilitating the periodic cleaning of circulating water.
Make anticorrosive medicine measure of adding for being convenient for according to corrosion monitoring result, it adds the medicine branch road to go back the branch connection on the circulation road pipe between circulation heating bucket export and the simulation pipeline import, it includes that the pipeline connects gradually buffer tank, check valve, dosing pump and adds the explosive barrel to add the medicine branch road.
In order to add circulating water, the inlet of the circulating heating barrel is also connected with a water adding pipeline in a branching manner.
Drawings
FIG. 1 is a schematic diagram of the sewage corrosion evaluating apparatus of the present invention.
Fig. 2 is a schematic structural view of the circulation heating barrel (end covers at two ends are omitted).
FIG. 3 is a schematic view of the film hanger.
Fig. 4 is a schematic structural diagram of the hanging piece mechanism.
Fig. 5 is a projection view of direction a in fig. 4.
Fig. 6 is a projection view in the direction B in fig. 4 (with the hanging pieces on both sides removed).
FIG. 7 is a graph comparing the correlation between the weight loss by hanging piece and the corrosion rate by AC impedance in example 2.
FIG. 8 is a graph comparing the correlation between the weight loss by hanging piece and the corrosion rate by resistance probe in example 3.
Wherein, 1 simulates a pipeline; 2, circulating the heating cylinder; 3, a circulating pump; 4, a one-way valve; 5 simulating a water inlet pipeline of the pipeline; 6 simulating a water outlet pipeline of the pipeline; 7, hanging a film seat; 701 a joint seat; 702a film hanging mechanism; 702A, a top rod; 702B a seal section; 702C connecting rod; 703 pressing a cap; 704 a sealing ring; 705 hanging piece mounting holes; 706 a mounting plane; 707 to indicate a line; 8, probe joints; 9, a buffer barrel; 10 a dosing pump; 11 a one-way valve; 12 a medicine adding barrel; 13 hanging the slices; 14 pins.
Detailed Description
Example 1
As shown in fig. 1-6, for the utility model discloses a sewage corrosion evaluation device, include through the simulation pipeline 1 and the circulation heating bucket 2 that circulation pipeline connects, circulation heating bucket 2's export is connected with the water inlet pipe 5 of simulation pipeline through circulating pump 3 and check valve 4, and circulation heating bucket 2's play import is connected with the outlet pipe 6 of simulation pipeline, and circulation heating bucket 2's heating system is connected with the temperature controller, is connected with at least one dismantled and assembled lacing film seat 7 and probe joint 8 on the pipe wall of simulation pipeline 1 respectively. In this embodiment, as shown in fig. 2, the simulation pipeline is a circular pipeline, and the pipeline both ends are sealed through the lid end to set up inlet and liquid outlet respectively, set up two lacing film seats 7 and two probe joints 8 on the pipe wall of simulation pipeline 1 respectively, nevertheless the utility model discloses an in the simulation pipeline, the quantity that sets up of lacing film seat and probe joint is not limited to the quantity of this embodiment, can set up more as required. The two ends of the simulation pipeline are respectively connected with the end covers in a sealing way, the end cover on each side is respectively provided with a water inlet and a water outlet, and the water inlet pipeline 5 of the simulation pipeline and the water outlet pipeline 6 of the simulation pipeline are respectively connected.
As shown in fig. 3, in order to facilitate quick replacement and installation of the hanging piece, the hanging piece seat 7 includes a connector seat 701 connected to the pipe wall of the simulation pipeline 1, a through stepped hole is formed in the center of the connector seat 701, a hanging piece mechanism 702 is hermetically inserted into the stepped hole, and a pressing cap 703 is connected between the hanging piece mechanism 702 and the stepped hole in a threaded manner. In order to ensure the sealing installation connection of the hanging piece mechanism 702 and the joint seat 701, an upper hole section, a middle hole section and a lower hole section which gradually shrink from the outside of the barrel to the inside of the barrel are arranged in a step hole of the joint seat 701, an internal thread matched with the outer periphery of the pressing cap 703 is arranged in the upper hole section, and the inner periphery of the middle hole section is in sealing fit with the hanging piece mechanism 702; the center of the pressing cap 703 is provided with a central hole; as shown in fig. 4, the film hanging mechanism 702 includes a top rod 702A slidably engaged with the central hole of the pressing cap 703, a sealing section 702B slidably engaged with the central hole section of the joint base 701 in a sealing manner is disposed on the lower side of the top rod 702A, the sealing section 702B is provided with an annular sealing groove, and a sealing ring 704 is disposed in the sealing groove; the downside of sealed section 702B is equipped with lacing film connecting rod 702C, lacing film connecting rod 702C lower part is equipped with lacing film connecting rod 702C axial vertically lacing film mounting hole 705, the side direction of lacing film connecting rod 702C of lacing film mounting hole 705 both sides is equipped with the mounting plane 706 of the lacing film laminating of being convenient for, as shown in fig. 5, this lacing film mounting hole 705's both sides all are provided with mounting plane 706, can realize that two side lacing films are connected, during the connection, two lacing films laminate respectively and connect on the mounting plane 706 of lacing film mounting hole 705 both sides, the rethread a pin 14 that runs through is fixed. In order to facilitate the accurate adjustment of the direction of the hanging piece 13 relative to the circulating liquid flow in the simulation pipeline 1 after the hanging piece is installed, an indication line 706 for indicating the installation direction of the hanging piece is arranged on the top end face of the ejector rod 702A of the hanging piece mechanism, the indication line passes through the central axis of the ejector rod, and the surfaces of the hanging pieces are parallel or vertical, so that the direction of the hanging piece 13 can be adjusted conveniently when the pressing cap 703 is screwed. Generally, according to the test requirements, the mounting direction of the hanging pieces relative to the liquid flow can be mounted downstream, and also can be mounted facing the liquid flow direction, or is mounted at a certain angle with the liquid flow direction, so as to measure the corrosion rate relative to different angle orientations.
In order to facilitate the replacement and installation of various chemical probes, the probe joint 8 is a pipe joint fixedly connected with the circulating heating barrel 2, the lower end of the pipe joint is connected with the wall of the circulating heating barrel, and an upper pipe orifice of the pipe joint is provided with an internal thread matched with the thread of the detection probe. The screw thread that this probe connects 8 and the screw-thread fit of testing chemical probe can realize the high-speed joint of different testing chemical probes, and when carrying out the chemical corrosion test, the chemical probe passes through the measured data line and is connected with chemical corrosion test instrument to realize the electrochemistry high-speed test.
In addition, in order to ensure the stability of the temperature of the circulating system, the circulating heating barrel 2 and the simulation pipeline are wrapped with heat-insulating layers; meanwhile, in order to facilitate the monitoring of the temperature and the pressure in the circulating system, a pressure gauge is connected to a circulating water pipe connected with the water outlet of the simulation pipeline; a temperature sensor is arranged in the circulating heating barrel.
A sewage draining outlet is arranged at the bottom of the circulating water circulating heating barrel 2 for facilitating the periodic cleaning.
In order to make an anti-corrosion dosing measure according to a corrosion monitoring result, a buffering barrel 9 is connected between the outlet of the circulating heating barrel 2 and a water inlet pipeline of the simulation pipeline in a branching mode, and a water inlet pipeline of the buffering barrel 9 is connected with a dosing barrel 12 through a one-way valve 11 and a dosing pump 10. In order to add circulating water, the inlet of the circulating heating barrel 2 is also connected with a water adding pipeline in a branching way.
The utility model discloses a sewage corrosion evaluation device, circulation heating bucket are used for storing the sewage of on-the-spot extraction, and simulation pipeline 1 passes through circulation pipeline and 2 circulation connections of circulation heating bucket, can simulate on-the-spot parameters such as pressure, velocity of flow and temperature of sewage and simulate the circulation operation, and a plurality of dismantled and assembled lacing film seats 7 and probe joint 8 that set up on the 1 wall of simulation pipeline are used for the average corrosion rate of indoor simulation lacing film weightlessness method to detect and electrochemical corrosion short-term test respectively. Meanwhile, the anti-corrosion dosing measures can be formulated by simulating field operation parameters through the dosing operation of the buffer barrel and the dosing barrel, and certain guiding significance is provided for field anti-corrosion monitoring and anti-corrosion measure formulation. Therefore, the utility model discloses a sewage corrosion evaluation device has following beneficial effect:
firstly, directly sampling a field corrosion medium as an experimental medium, and simulating parameters such as flow velocity, temperature and pressure of the field corrosion medium and the like influencing the field corrosion rate indoors, so that the method has more practical guiding significance for guiding field establishment of anticorrosion measures;
secondly, the electrochemical test method to be evaluated and the weightless hanging piece method run in the same simulation pipeline, parameters such as corrosion medium, temperature, flow rate and the like are consistent, and the evaluation result is more reasonable;
thirdly, in the simulation experiment process, the electrochemical method to be evaluated is tested on line, and is not required to be taken out for off-line testing, so that sampling test errors are eliminated, and the data is closer to the field pipeline corrosion data;
fourth, different electrochemical test probes can be mounted on the electrochemical probe mount, thereby enabling a variety of electrochemical corrosion tests to be performed.
Example 2:
in this example, the device for evaluating corrosion of wastewater in example 1 was used as a measuring device to perform comparative evaluation between the coupon weight loss method and the ac impedance method EIS.
1. Pre-treating hanging pieces and working electrodes:
taking four experimental hanging pieces made of 20 # steel, measuring the size by using a vernier caliper, recording length, width and height data, and calculating the surface area S according to the length, the width and the height data; then selecting a working electrode made of 20 # steel, sequentially polishing the working electrode on a polishing machine by using 200-mesh, 400-mesh, 600-mesh, 800-mesh and 1200-mesh water-polishing abrasive paper, putting the hanging piece with a measured size and the polished working electrode into a beaker filled with petroleum ether, cleaning the beaker with absorbent cotton to remove surface grease, soaking the beaker and the working electrode in absolute ethyl alcohol for 5 minutes to remove water, putting the dehydrated hanging piece and the working electrode on filter paper, placing the filter paper and the working electrode in a ventilation kitchen to be wrapped by the filter paper after the ethanol is completely volatilized, placing the filter paper in a drying tower to be dried for 24 hours, weighing the hanging piece and recording the weighed mass m to be accurate to 0.1 mg; then placing the pretreated hanging piece and the working electrode in a drying tower for drying for later use;
2. the device is connected, the sewage corrosion evaluation device is characterized in that a pretreated hanging piece 13 is installed on a hanging piece seat 7 of the sewage corrosion evaluation device and is inserted into a simulation pipeline 1, a working electrode is installed on an L RP electrochemical probe, then a L RP electrochemical probe is installed on a probe connector 8 and is inserted into the simulation pipeline 1, oilfield sewage in an oil field and an oil well field in Jiangsu is installed into a circulating heating barrel 2, a heating system is started to a set temperature, the set temperature is the same as the underground environment temperature of the oilfield sewage in the field, a circulating pump 3 is started, the opening pressure of a one-way valve 4 is adjusted, the sewage circularly flows through the simulation pipeline 1, the flow rate and the pressure of the sewage circulation are the same as the field circulation operation parameters, and a dosing branch is closed in the implementation process of the embodiment;
3. setting the cycle operation period of the hanging piece weight loss method as 7 days, in the cycle operation period, connecting the L RP electrochemical probe to the AC impedance meter host, sampling and recording 10 hours every day, testing and recording a group of corrosion rate data every 2 hours, recording related cycle operation parameters, timely adjusting to a set value, continuously sampling and testing for 7 days, and calculating the arithmetic average value r of the corrosion rateERn1At the end of each batch of test, connecting an L RP electrochemical probe with an electrochemical workstation, and measuring the data of a primary polarization curve;
4. and (3) corrosion rate calculation by a hanging piece weight loss method:
after 7 days of the circulating operation period, stopping the circulating pump, turning off the heating system, taking down the hanging piece from the hanging piece mechanism, flushing the hanging piece with clear water to remove residual oilfield sewage, putting the hanging piece into a beaker filled with petroleum ether, removing surface oil stains with absorbent cotton, putting the hanging piece into the beaker filled with pickling solution (consisting of 100m L hydrochloric acid, 10g hexamethylenetetramine and 900m L distilled water) to be soaked for 5 minutes, simultaneously slightly wiping the corrosion products with tweezers to clamp the absorbent cotton, taking out the test piece, flushing the test piece with clear water to remove the residual pickling solution on the surface, putting the test piece into the beaker filled with sodium hydroxide solution (60 g/L), taking out and flushing after 30 seconds, then putting the test piece into the beaker filled with sewage ethanol to be dehydrated for 2 times, taking out and putting the test piece on a ventilation kitchen, putting the test piece into a drying tower after the ethanol solution is completely volatilized, weighing the test piece for 24 hours and recording as m1To the accuracy of 0.1 mg/L according to the formula
Calculating the uniform corrosion rate rc1（rcThe uniform corrosion rate of the test piece is mm/a; m is a test piecePre-weighing, g; m is1Weighing the test piece after the test, g 8.7 × 104For calculation of the constant, S is the surface area of the test piece, cm2(ii) a t is experimental time, h; rho is the density of the material of a No. 20 steel test piece in g/cm3) The calculation results in rc1=559mm/a；
5. Repeating the steps 1-4 twice, and respectively measuring the corrosion rate r of the alternating current impedance detection method againERn2=0.774mm/a and rERn3=0.665 mm/a; corrosion rate r of weight loss method for hanging piecec2=0.684 mm/a、rc3=0.724mm/a；
6. And (3) analyzing experimental data:
and (3) by utilizing the data obtained in the steps 3-5, respectively drawing a broken line graph and a trend line for comparison according to the three test data of the hanging piece Weight loss method, which are respectively 0.559mm/a, 0.684mm/a and 0.724mm/a, and the average corrosion rate measured by the alternating current impedance method, which is respectively 0.740mm/a, 0.774mm/a and 0.665 mm/a), as shown in fig. 3, it can be seen from fig. 3 that the absolute value and the trend of the corrosion rate measured by the alternating current impedance method (EIS) are basically consistent with the absolute value and the trend of the corrosion rate measured by the Weight loss hanging piece method (Weight), which shows that the correlation between the absolute value and the trend is good, and the method can be used as a field rapid detection method for the corrosion rate of the sewage.
Example 3: the device for evaluating the corrosion rate of the sewage corrosion in the embodiment 1 is adopted to carry out the detection, comparison and evaluation of the weight loss of the hanging piece method and the corrosion rate of the resistance probe method
1. Preparation of the experiment:
taking 4 rectangular hanging pieces made of 20 # steel, measuring and recording the length, width and height dimensions by using a vernier caliper, calculating the surface area S of the hanging pieces according to the length, width and height dimensions, putting the hanging pieces with the measured dimensions into a beaker filled with petroleum ether, cleaning the hanging pieces by using absorbent cotton to remove surface grease, soaking the hanging pieces in absolute ethyl alcohol for 5 minutes to remove moisture, putting the dehydrated hanging pieces and resistance test pieces for electrochemical measurement on filter paper, putting the filter paper in a ventilation kitchen, packing the filter paper after the ethanol is completely volatilized, drying the filter paper in a drying tower for 24 hours, respectively weighing and marking the hanging pieces, recording the weighing mass m, accurately weighing the weighing mass m to 0.1mg, and then putting the hanging pieces in the drying tower for drying and storage for later use; placing a new resistance probe (resistance is No. 20 steel) into a beaker filled with petroleum ether, cleaning absorbent cotton to remove surface grease, soaking in absolute ethyl alcohol for 5 minutes to remove water, placing in a ventilation kitchen, wrapping with filter paper after the ethanol is completely volatilized, and drying in a drying tower for later use;
2. the device is connected:
connecting the sewage corrosion evaluation device shown in fig. 1, installing a pretreated hanging piece 13 on a hanging piece seat 7 of the sewage corrosion evaluation device, inserting the hanging piece into a simulation pipeline 1, installing an ER resistance probe on a probe joint 8, inserting the ER resistance probe into the simulation pipeline 1, sampling the oilfield sewage same as the embodiment, installing the oilfield sewage into a circulating heating barrel 2, starting a heating system to a set temperature which is the same as the underground environment temperature of the field oilfield sewage, starting a circulating pump 3, adjusting the opening pressure of a one-way valve 4, enabling the sewage to circularly flow through the simulation pipeline 1, enabling the flow rate and the pressure of the sewage circulation to be the same as the field circulation operation parameters, and closing a dosing branch in the implementation process of the embodiment;
3. detecting the corrosion rate by a resistance probe method:
setting the cycle operation period of the hanging piece weight loss method as 7 days, in the cycle operation period, connecting the ER resistance probe to a resistance probe tester host, testing and recording a group of corrosion rate data every 2 hours every day in 10 hours every day, recording related sewage cycle operation parameters, continuously recording the measurement data of 7 days, calculating the corrosion rate of the resistance probe method, and taking the arithmetic mean value rERn1=0.0048mm/a；
4. Detecting the corrosion rate of the hanging piece by a weight loss method:
after 7 days of the experimental period, the circulating pump is stopped, the heating system is turned off, the hanging piece is taken down from the hanging piece mechanism, clean water is used for washing and removing residual oil field sewage, the test piece is placed into a beaker filled with petroleum ether, degreased cotton is used for removing surface oil stain, the test piece is placed into the beaker filled with pickling solution (consisting of 100m L hydrochloric acid, 10g hexamethylenetetramine and 900m L distilled water) for soaking for 5 minutes, meanwhile, tweezers are used for slightly wiping and removing corrosion products by clamping the degreased cotton, the test piece is taken out and washed with clean water to remove the residual pickling solution on the surface, the test piece is placed into the beaker filled with sodium hydroxide solution (60 g/L), the test piece is taken out and washed after 30 seconds, the test piece is placed into the beaker filled with sewage ethanol for dewatering for 2 timesPutting the filter paper on a ventilation kitchen, putting the filter paper into a drying tower after the ethanol solution is completely volatilized, weighing the filter paper after 24 hours and recording the weight as m1To the accuracy of 0.1 mg/L according to the formula
Calculating the uniform corrosion rate and recording as rc1Wherein r iscThe uniform corrosion rate of the test piece is mm/a; m is the weight of the test piece before test, g; m is1Weighing the test piece after the test, g 8.7 × 104For calculation of the constant, S is the surface area of the test piece, cm2(ii) a t is experimental time, h; rho is the density of the material of a No. 20 steel test piece in g/cm3R obtained by this calculationc1=0.619mm/a；
5. Repeating the step 1-4 times, and measuring the corrosion rate r of the alternating current impedance detection methodERn2=0.0314 mm/a；rERn3Corrosion rate r of =0.0604mm/a and weightless hanging piece methodc2=0.335mm/a、rc3=0.220mm /a；
6. And (3) analyzing experimental data:
and (3) drawing a line graph and a trend line by using the data obtained in the steps (the distribution of the three-time test data of the Weight loss method of the hanging piece is 0.619mm/a, 0.335mm/a and 0.220mm/a, and the average corrosion rate measured by the resistance probe method is 0.0048mm/a, 0.0314 mm/a and 0.0604mm/a respectively) to compare with the graph shown in FIG. 4. As can be seen from FIG. 4, the absolute value and the trend of the corrosion rate measured by the resistance probe method (ER) basically have larger difference with the absolute value of the corrosion rate measured by the Weight loss hanging piece method (Weight), and the trend lines are opposite, which indicates that the two are not well associated and cannot be used as a field rapid detection method for the corrosion rate of a corrosion medium.
Therefore, the ac impedance method is preferentially adopted as the on-site rapid evaluation method of the corrosion rate and the corrosion inhibition measure of the corrosion medium according to the comparison result between the above example 2 and example 3.
Example 4
In this embodiment, a suitable corrosion inhibitor for sewage in an oil field is rapidly screened by an ac impedance method through the sewage corrosion evaluation apparatus shown in fig. 1 and 2.
1. Preparation of the experiment
Will NAnd the No. 80 steel is taken as a working electrode and is sequentially polished on a polishing machine by 200-mesh, 400-mesh, 600-mesh, 800-mesh and 1200-mesh water-mill abrasive paper, the polished working electrode is put into a beaker filled with petroleum ether, absorbent cotton is used for cleaning and removing surface grease, absolute ethyl alcohol is used for soaking for 5 minutes to remove moisture, the electrode is put on filter paper after dehydration, the filter paper is put in a ventilation kitchen to be wrapped after the ethanol is completely volatilized, and the electrode is put in a drying tower to be dried for later use. Respectively preparing enough CO with the mass concentration of 10%2Corrosion inhibitor-1, CO2Corrosion inhibitor-2, CO2Corrosion inhibitor-3 CO2Corrosion inhibitor-4 solution for standby;
2. the experiment starts:
connecting the sewage corrosion evaluation device shown in figure 1, installing the processed working electrode on an L RP electrochemical probe, installing a L RP electrochemical probe on a corresponding probe joint 8 on a simulation pipeline 1, loading the oilfield sewage taken from a certain well site of a Jiangsu oilfield into a circulating heating barrel 2, and performing corrosion evaluation on the oilfield sewage by using N2The gas cylinder is filled with N into the circulating heating barrel 22To remove oxygen from the plant and then remove CO2Introducing CO into corrosive medium in the circulating heating barrel 2 by the gas cylinder2When the sewage is saturated, simulating parameters such as the site operation temperature, flow velocity, pressure and the like of the sewage, and adjusting parameters of a heating system and operation parameters of a circulating pump 3 to ensure that the sampled sewage circularly operates in the sewage corrosion evaluation device;
3. raw water corrosion rate test
Connecting L RP electrochemical probe with AC impedance electrochemical tester, testing a group of corrosion rate data every 10min, recording related parameters, continuously taking four groups of data, and taking the average value of corrosion rate as the corrosion rate r of raw sewage0；
4、CO2Screening evaluation of Corrosion inhibitors
The prepared CO2In a corrosion inhibitor-1 dosing barrel 12, a pump is started, a dosing pump 10 and a one-way valve 11 are started to carry out dosing circulation according to the dosing concentration of 150 mg/L relative to the total circulating water quantity, a treated new working electrode is replaced on a L RP electrochemical probe, and CO is continuously saturated2The sewage is circulated in the sewage circulating system, a group of corrosion rate data is tested every 10min, andrecording related parameters, continuously taking four groups of data, and taking the arithmetic mean value of corrosion rate after corrosion inhibition treatment as the added CO2Corrosion rate r of sewage after corrosion inhibitor-11；
Changing the sewage, working electrode and corrosion inhibitor of the circulating system, and respectively testing the addition of CO by the same method2Corrosion inhibitor-2, CO2Corrosion inhibitor-3, CO2Corrosion rate r of corrosion inhibitor-4 for sewage2、r3、r4At the end of each batch of test, connecting the L RP electrochemical probe with an electrochemical workstation, and measuring the data of a primary polarization curve;
5. analysis of Experimental data
Using the data obtained in the steps 3-4 according to the slow release rate = (r)0-r)/ r0×% calculation method for calculating 4 kinds of CO respectively2The slow release rate of the corrosion inhibitor is calculated as follows:
| corrosion inhibitor | CO2Corrosion inhibitor-1 | CO2Corrosion inhibitor-2 | CO2Sustained-release agent-3 | CO2Corrosion inhibitor-4 |
| The slow release rate% | 81.5 | 92.3 | 73.8 | 72.4 |
From the results of the slow release rate comparison in the above table, four CO species can be determined2In the corrosion inhibitor, CO2The slow release effect of-2 in the corrosion inhibitor is best. Finally determining that the corrosion inhibitor used in the well site is CO2Corrosion inhibitor-2.
Claims (10)
1. The utility model provides a sewage corrosion evaluation device, its characterized in that includes simulation pipeline and circulation heating bucket through the circulation pipeline connection, is connected with circulating pump and check valve on the export of circulation heating bucket and the circulation pipeline of simulation pipeline import, the heating system of circulation heating bucket is connected with the temperature controller, be connected with at least one dismantled and assembled lacing film seat and probe joint on the pipe wall of simulation pipeline respectively.
2. The sewage corrosion evaluation device according to claim 1, wherein the hanging piece seat comprises a joint seat connected with the pipe wall of the simulation pipeline, a through stepped hole is formed in the center of the joint seat, a hanging piece mechanism is inserted into the stepped hole in a sealing mode, and a pressing cap is connected between the hanging piece mechanism and the stepped hole in a threaded mode.
3. The sewage corrosion evaluation device according to claim 2, wherein the stepped hole of the joint seat is provided with an upper hole section, a middle hole section and a lower hole section which are gradually contracted from the outside of the barrel to the inside of the barrel, an internal thread matched with the outer periphery of the pressing cap is arranged in the upper hole section, and the inner periphery of the middle hole section is in sealing fit with the hanging piece mechanism; the center of the pressing cap is provided with a center hole, the hanging piece mechanism comprises an ejector rod in sliding fit with the center hole of the pressing cap, the lower side of the ejector rod is provided with a sealing section in sliding seal fit with the center hole section of the joint seat, the sealing section is provided with an annular sealing groove, and a sealing ring is arranged in the sealing groove; the lower side of the sealing section is provided with a hanging piece connecting rod, the lower portion of the hanging piece connecting rod is provided with a hanging piece mounting hole which is axially vertical to the hanging piece connecting rod, and the hanging piece connecting rods on the two sides of the hanging piece mounting hole are laterally provided with planes which are convenient for the hanging piece to be attached and mounted.
4. The sewage corrosion evaluation device of claim 3, wherein the hanging piece mechanism is a double-hanging piece connecting mechanism, and the double-hanging piece is respectively connected to two sides of the hanging piece mounting hole of the hanging piece connecting rod and fixed through a pin.
5. The sewage corrosion evaluating apparatus according to claim 3, wherein an indication line for indicating a mounting direction of the hanging piece is provided on a top end surface of the ejector rod of the hanging piece mechanism, the indication line passing through a central axis of the ejector rod.
6. The sewage corrosion evaluating apparatus according to claim 1, wherein the probe connector is a pipe connector fixedly connected to the circulation heating barrel, a lower end of the pipe connector is connected to a wall of the circulation heating barrel, and an upper pipe opening of the pipe connector is provided with an internal thread matched with the thread of the detection probe.
7. The sewage corrosion evaluating apparatus according to claim 1, wherein the circulating heating tank and the simulation pipeline are wrapped with heat insulating layers at the periphery; a pressure gauge is connected to the circulating water pipe connected with the water outlet of the simulation pipeline; and a temperature sensor is arranged in the circulating heating barrel.
8. The sewage corrosion evaluating apparatus according to claim 1, wherein a drain outlet is provided at a bottom of the circulation heating tank.
9. The sewage corrosion evaluation device according to claim 1, wherein a dosing branch is further connected to a circulation path pipe between the outlet of the circulation heating barrel and the inlet of the simulation pipeline in a branched manner, and the dosing branch comprises a buffer barrel, a one-way valve, a dosing pump and a dosing barrel which are sequentially connected through a pipeline.
10. The apparatus for evaluating corrosion of wastewater according to claim 1, wherein the inlet of the circulation heating tank is further branched and connected with a water supply pipeline.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921784968.2U CN211043067U (en) | 2019-10-23 | 2019-10-23 | Sewage corrosion evaluation device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921784968.2U CN211043067U (en) | 2019-10-23 | 2019-10-23 | Sewage corrosion evaluation device |
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| CN211043067U true CN211043067U (en) | 2020-07-17 |
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| CN201921784968.2U Active CN211043067U (en) | 2019-10-23 | 2019-10-23 | Sewage corrosion evaluation device |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114486712A (en) * | 2021-12-31 | 2022-05-13 | 武汉理工大学 | Device and method for simulating dynamic metal corrosion in deep geological disposal environment |
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2019
- 2019-10-23 CN CN201921784968.2U patent/CN211043067U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114486712A (en) * | 2021-12-31 | 2022-05-13 | 武汉理工大学 | Device and method for simulating dynamic metal corrosion in deep geological disposal environment |
| CN114486712B (en) * | 2021-12-31 | 2023-12-15 | 武汉理工大学 | Device and method for simulating dynamic corrosion of metal in deep geological treatment environment |
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