SY/T 0528-1993 Determination of trace arsenic content in crude oil Atomic absorption spectrometry SY/T0528-1993 standard download decompression password: www.bzxz.net

Petroleum and Natural Gas Industry Standard of the People's Republic of China SY/T 0528—93
Determination of trace arsenic content in crude oil
Atomic absorption spectrometry
Published on January 6, 1994
China National Petroleum Corporation
Implementation on June 1, 1994wwW.bzxz.Net
1 Subject content and applicable scope
Petroleum and Natural Gas Industry Standard of the People's Republic of China Determination of trace arsenic content in crude oil
Atomic absorption spectrometry
SY/T 0528—93
This standard specifies the method for determining the arsenic content in crude oil after wet digestion pretreatment by atomic absorption spectrometry. This standard is applicable to the determination of arsenic content in crude oil, and the determination range is arsenic content 0.13ug/g. 2 Reference Standards
SH/T0167 Determination of Arsenic Content in Reforming Raw Oil (Spectrophotometry) 3 Method Overview
Add acid to the sample and heat to extract the indole in the crude oil, add potassium iodide and tin dichloride to reduce it to trivalent indole. Then add excess zinc powder to the solution, and the zinc powder reacts with the acid to generate new hydrogen. Due to the presence of these new hydrogen, arsenic is quantitatively converted into gaseous indole hydrogen. Arsine hydrogen has a relatively low bond energy and is easily decomposed at high temperatures to produce arsenic atoms. Taking advantage of this characteristic, use argon as a carrier, input arsenic hydrogen gas into an atomic absorption spectrophotometer, and select hydrogen-argon flame combustion to determine the arsenic content in the sample. 4 Materials and Reagents
a. High-purity hydrogen:
b. High-purity argon:
Arsenic trioxide: spectral grade
Potassium iodide: analytical grade
Lead acetate: analytical grade
Sulfuric acid: premium grade
9. Hydrochloric acid, premium grade,
h. Zinc powder: premium grade.
i. "Stannic nitride, analytical grade.
j. Hydrogen peroxide, analytical grade.
5.1 Atomic absorption spectrophotometer with hydride generator: See Figure 1 for a schematic diagram of the hydride generator.
5.3 Analytical balance, sensitivity 0.1 mg.
Approved by China National Petroleum and Natural Gas Corporation on January 6, 1994 and implemented on June 1, 1994
6 Solution preparation
6.1 Arsenic standard solution
Prepare according to Article 4.3 of SH/T0167.
6.2 Potassium iodide solution (15%)
SY/T 0528—93
Reactor
Magnetic stirrer
Figure 1 Schematic diagram of hydride generator
Weigh 15g of analytically pure potassium iodide and dissolve it in 100ml of deionized water. 6.3 Fluoride dioxide pot connection (20%)
B-type tube
Weigh 20g of analytically pure tin dioxide and dissolve it in 50ml of hydrochloric acid. Heat slowly. When the solution becomes transparent, cool the solution and dilute it to 100ml with deionized water.
6.4 Lead acyl chloride solution (10%)
Dissolve 10g analytically pure lead acetate in 100ml deionized water. 6.51±1 Sulfuric Acid
Measure 500ml of high-grade pure sulfuric acid, slowly add it to 500ml of deionized water under constant stirring, and place it to cool to room temperature for later use.
7 Test Steps
1According to the content of crude oil, accurately weigh a certain amount of dehydrated crude oil into a beaker or a conical flask, add 40ml of 1+1 sulfuric acid, and slowly heat until a large amount of trioxide white powder emerges from the beaker. Stop heating when smoke appears, add 1020ml hydrogen peroxide after cooling, continue heating until a large amount of trioxide white smoke emerges, then stop heating. After standing and stratifying, transfer the lower layer of acid solution into a volumetric flask. Add deionized water to the residual oil, slowly heat and stir until the crude oil is dissolved. Continue heating to 70~80℃ and then stop heating. After standing and stratifying, transfer the deionized water into a volumetric flask, and repeat this operation 3~5 times. Dilute the solution to the scale. 7.2 Accurately measure the above solution according to different arsenic contents and the optimal measurement range of the atomic absorption spectrophotometer. Several milliliters are placed in the reaction bottle of the hydride generator, and deionized water is added to make the solution volume reach 25-50 ml. Add 1+1 salt to adjust the acidity to pH <3, add 5 ml potassium iodide solution and 2 ml dichloride solution, put in a magnetic bar, and stir thoroughly with a magnetic stirrer for 10 minutes at room temperature for later use.
7.3 Put the absorbent cotton soaked in lead acetate solution into a U-shaped tube, one end of which is connected to the atomic absorption spectrophotometer and the other end is connected to the hydride generator.
SY/T 0528--93
7.4 Operate according to the operating procedures of the hydride generator. 8. Determination of the results
Measure the absorbance of arsenic on an atomic absorption spectrophotometer. According to the content of arsenic in the sample, at least 5 standard solutions (excluding the zero point) are prepared to make the concentration of the sample to be tested within the range of the calibration curve. Under the same conditions as the determination of the arsenic content in crude oil, measure its absorbance respectively. Draw a calibration curve with the concentration of the standard solution as the horizontal axis and the corresponding absorbance as the vertical axis. Find the concentration of the arsenic to be tested in the sample solution on the calibration curve (see Figure 2). The concentration can also be calculated by the regression equation method based on the measured absorbance. 20.00
9 Precision
9.1 Repeatability
Sample absorbance
Measured element density
Standard solution liquid C, ug/ml
Figure 2 Calibration curve
The same test method is used for the same sample, and the same operator uses the same equipment in the same laboratory and independently tests them within a short period of time.
Repeatability, r=0.07
9.2 Reproducibility
The same test method is used for the same sample, and different equipment is used to test it in different laboratories. Reproducibility, R=0.13
Additional remarks:
This standard is proposed by the Science and Technology Development Bureau of China National Petroleum Corporation. This standard is under the jurisdiction of the Petroleum Planning and Design Institute of China National Petroleum Corporation. This standard is drafted by the Oilfield Construction Design Institute of Daqing Petroleum Administration Bureau. The main drafters of this standard are An Yanbin and Shao Jianmei.
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