There are various methods for determining the sulfur content of paraffin oil, and the following are some common methods:
Lamp burning method
Principle: The paraffin oil sample is burned in a lamp, and the generated sulfur dioxide is absorbed by excess sodium carbonate solution. Then, the remaining sodium carbonate is titrated with a standard acid solution, and the sulfur content is calculated based on the amount of acid consumed.
Scope of application: Suitable for paraffin oil samples with low sulfur content, generally measured within the range of 0.05% -0.5%.
Operation points: Accurately weigh the sample, control the combustion conditions, ensure complete combustion of the sample, and pay attention to the amount of absorbent and the accuracy of titration operation.
Tube furnace method
Principle: The paraffin oil sample is burned at high temperature in a tube furnace to convert sulfur into sulfur dioxide, which is then absorbed and titrated with potassium iodate potassium iodide solution. The sulfur content is calculated based on the amount of potassium iodate standard solution consumed.
Scope of application: Can be used to determine paraffin oil samples with sulfur content ranging from 0.1% to 10%.
Operation points: It is necessary to strictly control the temperature and combustion time of the tube furnace to ensure that the sample is fully burned. At the same time, it is necessary to accurately prepare and use potassium iodate potassium iodide absorption solution and standard titration solution.
Oxygen bomb combustion method
Principle: Place the sample in an oxygen bomb, fill it with oxygen, ignite it, and burn the sulfur in the sample to produce sulfur dioxide and sulfur trioxide. Then, absorb them with an alkaline solution and determine the sulfur content using acid-base titration or colorimetric methods.
Scope of application: Suitable for paraffin oil samples with various sulfur contents, especially for accurate determination of high sulfur content samples.
Operation points: The sealing of the oxygen bomb should be good, the oxygen filling pressure should meet the requirements, the combustion should be complete, the absorption process should be sufficient, and accurate operation should be carried out according to different subsequent measurement methods.
Microcoulometric method
Principle: The sample is mixed and burned with oxygen in a cracking tube, and sulfur is converted into sulfur dioxide. It enters the titration cell and reacts with silver ions. The sulfur content is calculated by measuring the amount of electricity consumed to produce silver ions through electrolysis.
Scope of application: Suitable for paraffin oil samples with sulfur content ranging from 0.1mg/L to 1000mg/L, with high sensitivity and accuracy.
Operation points: Ensure stable temperature of the cracking tube, accurate gas flow rate, good electrode performance of the titration cell, and accurate calibration and blank testing of the instrument.
Energy dispersive X-ray fluorescence spectroscopy (EDXRF)
Principle: By irradiating the sample with X-rays, the sulfur element in the sample emits characteristic X-ray fluorescence, and the sulfur content is quantitatively analyzed by detecting the intensity of the fluorescence.
Scope of application: Suitable for paraffin oil samples with sulfur content ranging from 0.01% to 10%, it can achieve rapid and non-destructive testing.
Operation points: The preparation of the sample should be uniform, avoiding the influence of factors such as particle size and thickness on the measurement results. At the same time, the instrument should be calibrated and maintained regularly to ensure the accuracy of the measurement.