SY/T 0095-2000 Test method for laboratory evaluation of buried magnesium sacrificial anode specimens
Some standard content:
ICS77.120.20
Registration number: 8178-2001
Petroleum and natural gas industry standard of the People's Republic of China SY/T 0095-2000
Test method for laboratory evaluation of magnesium sacrificial anode test specimens for underground applications2000-12-25 Issued
State Administration of Petroleum and Chemical Industry
200106-01 Implementation
SY/T 0095-2000
Cited standards
3 Method summary
4 Instruments and equipment
5 Reagents
Sample preparation
Test procedures
8 Calculation and report
Precision and deviation
SY/T 0095—2000
This standard is to be formulated to standardize the test method of the performance of magnesium sacrificial anode. This standard is equivalent to ASTM G97-89 "Standard Test Method for Laboratory Evaluation of Magnesium Sacrificial Anode Samples" (confirmed in 1995): This standard is proposed by China National Petroleum Corporation. This standard is approved by the Planning Institute of China National Petroleum Corporation. This standard was drafted by China Shishan Natural Gas Pipeline Engineering Co., Ltd. and Tianjin People's University. The drafters of this standard are Hu Shixin, Li Shuiliang, Xue Zhiyuan, Meng Xianji, and China Petroleum and Natural Gas Pipeline Engineering Co., Ltd. This standard is entrusted to China Petroleum and Natural Gas Pipeline Engineering Co., Ltd. for interpretation: 1 Scope || ... The most typical formula of packing material is: 75% gypsum powder (CaSO2HO), 20% bentonite and 5% sodium sulfate (NA4). This standard uses calcium sulfate and magnesium hydroxide electrolyte to simulate the long-term environmental conditions in gypsum-bentonite-sodium sulfate packing material. 1.2 Anode manufacturers or anode users can use this standard to identify the quality of magnesium cathodes: 2 Reference standards
The provisions contained in the following standards constitute the provisions recommended by this standard through reference in this standard: When this standard is published, the versions shown are valid. All standards will be revised, and parties using this standard should explore the possibility of using the latest version of the following standards. GB/T6682·-92 Specifications and test methods for water used in analytical laboratories CB/T12336-1990 Standard method for statistical analysis of corrosion data GB/T13671—1992 Electrochemical test method for crevice corrosion of stainless steel 3 Method summary
A known direct current is passed through several test units connected in series. Each test unit includes a magnesium anode sample with a pre-weighed mass, a steel tank that also serves as a cathode, and an electrolyte with a known composition. During the 141 test period, the oxidation potential of the sample is measured several times. After the test is completed, the power is turned off for 1 hour and then measured again. The total amount of electricity (Q) passing through the test unit is measured: After the test is completed, each sample is cleaned and weighed, and the amount of electricity (9) consumed per unit sample mass is calculated. 4 Instruments and equipment
4.1 DC power supply, which can provide at least 2mA current and 12V voltage. 4.2 Steel tank, its structure is shown in Figure 1.
4.3 Copper coulometer (its structure is shown in Figure 2) or electronic coulometer4.4 Saturated calomel reference electrode.
4.5 Potentiometer, input impedance greater than or equal to 10Ω4.6 Balance, maximum weighing 100g, sensitivity 0.1mg. 4.7 Oven, working temperature can reach 110.
5 Reagents
5.1 Test electrolyte: Add 5.0g of CaS04-2HO and 0.1g of Mg(OH)z into 1000mLCB/T66821992 State Administration of Petroleum and Chemical Industry 2000-12-25 Approved 2001 06 - (1 Implement the third-level water specified in
SY/T0095-2000
12.7mm aperture
(for placing reference electrode)
12.7mm aperture
(for placing anode)
Rubber stopper
M8 bolts, nuts
75mmQ-235A3 steel pipe
165m long, capacity about 625ml
Plastic plate poured here, about
3mm thick (commercially available epoxy)
Steel plate welded bottom
Schematic diagram of steel tank structure
Figure 2 Schematic diagram of copper coulometer structurebzxZ.net
￥0.985m multi-strand copper wire
belt Connecting piece
Pre-weighed cathode copper wire,
diameter 0.51mm
Rubber cold
300mL glass
Copper plate
1.54mm (two pieces)
5.2 Coulometer solution: Add 235g CuSO45HO, 27mL98% 1SO4 and 50cm3 anhydrous ethanol to 900mL GB/T6682-1992 specified level 3 water or higher level analysis room water 5.3 Anode cleaning solution: Add 250g CrO to 1000mL GB/T6682-1992 specified level 3 water or higher level analysis room water
Note: Operation using coulometer When using solutions and cleaning solutions, you must protect your eyes and skin, and the cleaning of the samples should be carried out in a fume hood. 6 Sample preparation
SY/T0095—2000
6.1 Select and prepare the sample of the cast anode as shown in Figure 3. The sampling position should be 13mm away from the bottom surface. First, use sawing to obtain a rough piece of 180mm×16mm×16mm, and mark one end face of the rough piece with a permanent number. Then use a lathe to dry process to prepare a 12.7mm formal sample. The lathe operating parameters are: machine speed 800r/min, tool speed 0.5mm/t, cutting depth less than or equal to 1.9mm. The machined sample is cut into a length of 152mm at the non-marked end, and the end face is fine-machined. When supplied If it is difficult to sample the anode for testing according to the provisions of 6.1, the sample can be sampled according to the actual situation. Note: During cutting and turning operations, magnesium chips are in danger of ignition and should be strictly observed. 180m
Typical 7.7kg cast anode
See center cut
Sketch of section
About 16mm×16m×180mm
Machinery sample
Net 12.7mm (±0.2mm) x152m
Figure 3 Sample preparation from cast anode
6.2 Wash each machined sample with distilled water, then with acetone, dry in an oven at 105℃ (see 4.7) for 30min, and weigh to the nearest 0.1mg after cooling.
Note: When handling the sample after acetone cleaning, the operator should wear clean gloves to prevent contamination of the sample. 6.3 Shield the weighed sample with insulating tape, starting from 100 mm above the bottom to 13 mm from the top. The area exposed to the electrolyte (see 5.1) is the bottom plus the side with a length of 100 mm, which is 41.2 cm2. The current of the test circuit is 1.60 mA, and the anode current density is 0.039 mA/cm.
6.4 Wipe the steel can (see 4.2) with a soft plastic brush. If the inner surface of the steel can (see 4.2) is covered with a high-resistance coating, sandblasting, wire brushing, or scraping should be used to remove hard attachments on the surface. 6.5 The copper coulometer (see 4.3) is prepared according to Figure 2. Polish the copper wire used for the coulometer with a fine abrasive (00 fineness or finer), dry it in an oven (see 4.7) at 105°C for 15 min, then cool it and weigh it. The length of the copper wire immersed in the coulometer solution (see 5.2) is 10 to 50 mm: the copper plate anode should be cleaned before being installed in the coulometer (see 4.3), and the purity of the copper wire and copper sheet should be greater than or equal to 99.9%
6.6 Figure 4 is a schematic diagram of the entire test circuit wiring. The insulated multi-strand copper wire with a cross-sectional area of 0.985mm2 is equipped with crocodile SY/T 0095--2000
or terminal lugs at both ends of each wire. The saturated calomel electrode (see 4.4) is only used when measuring the oxidation potential. 7 Test steps
7.1 Fill the anode test electrolyte (see 5.1) into the steel tank (see 4.2) that also serves as the cathode, until it is 15mm from the top. 7.2 Insert the sample into the rubber plug of the steel tank (see 4.2), and then install the rubber plug with the sample on the steel tank (see 4.2) that also serves as the cathode.
7.3 Connect the wires according to Figure 4
Connect the potentiometer
P—current source:—Cuus4 coulombmeter; E—calomel electrode Figure 4 Schematic diagram of test circuit wiring
7.4 Turn on the power supply (see 4.1) and adjust the current to 1.60mA. 7.5 On the 1st day, 7th day and 14th day, use a saturated 20-mercury plate (see 4.4) and a potentiometer (see 4.5) to measure the closed circuit potential of each sample (as shown in Figure 4); according to the provisions of GB/T13671, the tip of the calomel electrode (see 4.4) should be within 10nm from the surface of the sample during the measurement
7.6 During the test, the temperature of the electrolyte (see 5.1) should be 22℃15℃. 7.7 After 14 days, cut off the power supply: 1h after the power is off, measure the open circuit potential of the sample. The measurement method is the same as the measurement of the closed circuit potential (see 7.5).
7.8 Remove the connecting wires from the sample, remove the rubber plug from the steel can (see 4.1), and take out the sample from the plug and remove the tape on the sample.
7.9 Place a blank sample in a cleaning solution (see 5.3) preheated to 60~80℃, place it for 10 minutes, rinse it with tap water and dry it in a 105℃ oven (see 4.7) for 30 minutes. If the weight loss of the blank sample is less than 5 mg, pour out the cleaning solution (see 5.3). If the weight loss of the blank sample is less than 5g, place the sample and the sample in a cleaning solution (see 5.3) at 60~80℃, place it for 10 minutes, rinse it with tap water, and dry it in a 105℃ oven (see 4.7) for 3 hours. If the weight loss of the blank sample is greater than 5 mg, repeat the above test.
7.10 Another optional cleaning method is to place the blank sample in the cleaning solution (see 5.3) at 6080℃ for 10 minutes instead of soaking it in the cleaning solution (see 5.3) at room temperature for 30 minutes. 0095—2000
Juice: Used chemical waste liquid should be handled in accordance with the relevant provisions of national environmental protection laws and regulations. 7,11 If a copper bed coulometer (see 4.3) is used, the copper wire removed from the copper coulometer (see 4.3) should be rinsed with tap water and dried in a 105t oven (see 4.7) for 30ri7.12 Take out the sample, blank sample, and copper wire of the coulometer (see 4.3) from the oven (see 4.7), cool to room temperature, and weigh to an accuracy of 0.1mgs
Note: To avoid contamination of the sample and the copper wire of the copper coulometer (see 4.3), wear clean gloves when weighing. 8 Calculation and Report
8.1: Calculate and report the value of the charge (Q) of the test unit during the 14d test period. 8.1.1 If a copper coulometer (see 4.3) is used, the value of the charge (Q) is calculated as shown in formula (1): Q = R(M2 - Mo)
Formula: Q - the amount of electricity passing through the test unit, A·h: K--electrochemical equivalent, U.8433A-h/g; M2 - the mass of the copper wire of the coulombmeter after the test, g: M, - the mass of the copper wire of the coulombmeter before the test, ge8.1.2 If an electronic coulombmeter is used, the value of the quantity of electricity (Q) can be read directly from the electronic coulombmeter: 8.2 Calculate and report the quantity of electricity (4) produced by each unit mass of the consumed sample according to formula (2): q = Q/(MmR) -Mm2)
Where: 9——Amount of electricity generated per unit mass, A·h/g; Mmgl—initial mass of magnesium anode sample, g; Mmz—mass of magnesium anode sample after test, g8.3 Report the open circuit and closed circuit potential measurement values of each sample. 9 Precision and deviation
9.1 According to the provisions of GF/T123.36, evaluate whether the results are within the 5% confidence range according to the following data. (1)
9.1.1 Repeatability: The difference between the average value of 5 samples (the samples are completely identical) obtained by the same operator and the average value of another 5 parallel samples is greater than the following value , the measurement result should be considered unreliable: 9 value
Final closed-circuit potential
Open-circuit potential
9.1.2 Reproducibility: If the difference between the average value of 5 samples submitted by a certain laboratory (the samples are completely identical) and the average value of 5 samples from another laboratory is greater than the following values, the measurement result should be considered unreliable: 4 value
Final closed-circuit potential
Open-circuit potential
0.15A·h/g
9.1.3 Due to the unevenness of the casting itself, several samples taken from the same casting may not be completely identical. One way to ensure that the samples being evaluated are completely equivalent is to repeat the test of the same sample. Before repeating the test, use machining to re-level the surface of the sample: measure the new diameter value and adjust the test current density to 0.039mA/cm29.2 The median value and the amount of electricity consumed by the mass obtained according to this standard may not be consistent with the results obtained in the field application. The results on site are generally less than the measured values of this standard.3), then the calculation of the value of charge (Q) is as follows: Q = R(M2 - Mo)
Formula: Q - the amount of electricity passing through the test unit, A·h: K--electrochemical equivalent, U.8433A-h/g; M2 - the mass of the copper wire of the coulombmeter after the test, g: M, - the mass of the copper wire of the coulombmeter before the test, ge8.1.2 If an electronic coulombmeter is used, the value of charge (Q) can be read directly from the electronic coulombmeter: 8.2 Calculate and report the amount of electricity produced by each unit mass of consumed sample according to formula (2): q = Q/(MmR) -Mm2)
Where: 9 - the amount of electricity produced per unit mass, A·h/g; Mmgl - the initial mass of the magnesium anode sample, g; Mmz - the mass of the magnesium anode sample after the test, g8.3 Report the open circuit and closed circuit potential measurement values of each sample. 9 Precision and deviation
9.1 According to the provisions of GF/T123.36, use the following data to evaluate whether the results are within the 5% confidence range. (1)
9.1.1 Repeatability: If the difference between the average value of 5 samples (completely identical) obtained by the same operator and the average value of another 5 parallel samples is greater than the following value, the measurement result should be considered unreliable: 9 value
Final closed-circuit potential
Open-circuit potential
9.1.2 Reproducibility: If the difference between the average value of 5 samples (completely identical) submitted by a certain laboratory and the average value of 5 samples from another laboratory is greater than the following value, the measurement result should be considered unreliable: 4 value
Final closed-circuit potential
Open-circuit potential
0.15A·h/g
9.1.3 Due to the unevenness of the casting itself, several samples taken from the same casting may not be completely identical. One way to ensure that the samples being evaluated are completely equivalent is to repeat the test of the same sample. Before repeating the test, use machining to re-level the surface of the sample: measure the new diameter value and adjust the test current density to 0.039mA/cm29.2 The median value and the amount of electricity consumed by the mass obtained according to this standard may not be consistent with the results obtained in the field application. The results on site are generally less than the measured values of this standard.3), then the calculation of the value of charge (Q) is as follows: Q = R(M2 - Mo)
Formula: Q - the amount of electricity passing through the test unit, A·h: K--electrochemical equivalent, U.8433A-h/g; M2 - the mass of the copper wire of the coulombmeter after the test, g: M, - the mass of the copper wire of the coulombmeter before the test, ge8.1.2 If an electronic coulombmeter is used, the value of charge (Q) can be read directly from the electronic coulombmeter: 8.2 Calculate and report the amount of electricity produced by each unit mass of consumed sample according to formula (2): q = Q/(MmR) -Mm2)
Where: 9 - the amount of electricity produced per unit mass, A·h/g; Mmgl - the initial mass of the magnesium anode sample, g; Mmz - the mass of the magnesium anode sample after the test, g8.3 Report the open circuit and closed circuit potential measurement values of each sample. 9 Precision and deviation
9.1 According to the provisions of GF/T123.36, use the following data to evaluate whether the results are within the 5% confidence range. (1)
9.1.1 Repeatability: If the difference between the average value of 5 samples (completely identical) obtained by the same operator and the average value of another 5 parallel samples is greater than the following value, the measurement result should be considered unreliable: 9 value
Final closed-circuit potential
Open-circuit potential
9.1.2 Reproducibility: If the difference between the average value of 5 samples (completely identical) submitted by a certain laboratory and the average value of 5 samples from another laboratory is greater than the following value, the measurement result should be considered unreliable: 4 value
Final closed-circuit potential
Open-circuit potential
0.15A·h/g
9.1.3 Due to the unevenness of the casting itself, several samples taken from the same casting may not be completely identical. One way to ensure that the samples being evaluated are completely equivalent is to repeat the test of the same sample. Before repeating the test, use machining to re-level the surface of the sample: measure the new diameter value and adjust the test current density to 0.039mA/cm29.2 The median value and the amount of electricity consumed by the mass obtained according to this standard may not be consistent with the results obtained in the field application. The results on site are generally less than the measured values of this standard.
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