About the principle of the instrument (tester)

The principle of sulfur analyzer: According to the Coulomb titration principle, the coal sample is burned in the purified air stream under the high temperature conditions of 1150°C and the catalyst. Various forms of sulfur in the coal are burned and decomposed into SO2. With a small amount of SO3 gas, the purified air stream is brought into the electrolytic cell to generate H2SO3 or a small amount of H2SO4. H2SO3 is immediately oxidized by I2 (Br2) in the electrolyte to H2SO4. As a result, I2 (Br2) in the solution is reduced and I ( Br) increases, destroys the equilibrium state of the electrolyte, indicates that the potential between the electrodes rises, the instrument automatically judges to start the electrolysis, and controls the size and time of the corresponding electrolysis current according to the potential level on the indication electrode, so that the electrolysis electrode The amount of I2 (Br2) generated on the reaction with H2SO3 is equalized, so that the electrolyte is returned to equilibrium and the process is repeated until the end of the test. Finally, the instrument calculates the total sulfur content in the sample according to the Faraday's law of electrolysis based on the integral of electricity consumed by the electrolytic production of I2 (Br2).

Sulphur analyzer configuration Sulphur analyzer component structure and function Sulphur analyzer includes high temperature pyrolysis furnace, sample delivery mechanism, electrolytic cell and agitator, air purification system, control system and so on.

Structure and function of each component 1. Control system:

SCM control and general-purpose computer control are two kinds, mainly used to run the sulfur measurement program, provide man-machine interface; and deal with the acquisition of data; Coulomb electricity, integration and sulfur content calculation; results of the display, print and save; and issued Various control commands control the normal operation of the entire system.

2, pyrolysis furnace:

Furnace body and enclosure: Insulated silicon carbon tube: (double thread) Heating element Corundum tube: Isolated, trapped gas, sample feeding channel Thermocouple: Temperature sensor Quartz boat: Sample carrier 3, Sample delivery mechanism:

The sample delivery mechanism is composed of a reversible motor, a rack, a sample delivery rod, and a limit switch. Its role is to send (retreat) the sample to the high-temperature furnace.

4. Electrolytic cell:

(1) The electrolysis cell is mainly used for the Coulomb titration in the determination of total sulfur. The electrolysis cell is made of organic glass with a volume of 400 ml. It is sealed with rubber between the cover and the shell and fixed with four screws. A pair of Pt22 (platinum) indicator electrodes (15 mm) and a pair of Pt (platinum) electrode (150 mm) were placed on the cover; each pair of electrodes was parallel to each other, and the two pairs of electrodes were aligned.

(2) There is a stirrer in the electrolytic cell, which is rotated by the magnetic block on the stirrer to rotate the rotor, so that the electrolyte is rotated to achieve stirring.

(3) Gas filter: Disperse the gas into many small bubbles, increase the contact area between the gas and the electrolyte, and fully absorb the gas.

5. Magnetic stirrer: The magnetic stirrer is composed of a motor, a control circuit and a counterpart magnet. The rotating magnetic force drives the stirrer in the electrolytic cell to rotate. On the one hand, the SO2 gas is fully absorbed, and on the other hand, the anode is precipitated. Iodine and bromine diffuse rapidly.

6, the air purification system This part consists of electromagnetic pumps, flow meters (0 ~ 1000ml/min), dryers, two-way valves and other components, its role is to enter the air in the high temperature furnace and the air into the electromagnetic pump purification treatment: A dry and pure air atmosphere is formed.

(1) Electromagnetic pump: The electromagnetic pump is composed of a transformer, a vibrating plate, a magnet and a cup. The working principle is to use electromagnetic force to make the vibrating plate vibrate back and forth to compress the crust and generate compressed gas to achieve suction and exhaust. The pump has Two airways, which can be inhaled and vented separately. The role of the electromagnetic pump is as follows: First, the gas containing SO2 in the high temperature furnace is pumped into the electrolytic cell for electrolysis. The second is the treatment of dry, pure air supplied to a high temperature furnace as a carrier for SO2 gas.

(2) Flowmeter: The flowmeter is also called a glass flowmeter and is equipped with a needle opening valve to regulate the air flow. A metal float is inside to indicate the flow of gas. During the test, the flow rate of air is adjusted to about 1000ml/min. The role of the flow meter is to regulate and indicate the gas flow.

(3) Desiccator: The desiccator consists of three plexiglass tubes, two of which are equipped with color-changing silica gel, which is mainly used to absorb 5 parts of water in a sulfur-contained sulfur training material, and the other is filled with sodium hydroxide (grain or flakes). It mainly absorbs acid gases from the air.

(4) Filters: It is mainly to prevent the ash from entering the electrolytic cell in the high-temperature furnace, and the glass melting plate that blocks the electrolytic cell cup will affect the normal test.

The performance characteristics of the sulfur analyzer use an integrated structural design, eliminating general-purpose computers and printers, greatly reducing the volume and footprint, and also reducing the failure rate.

Using the latest 16-bit microcontroller control. With a large-screen graphic LCD display, all information and menus are displayed in Chinese characters, which is easy to see at a glance.

The overall structural design is reasonable, the appearance is beautiful, exquisite, the performance is stable, the result is accurate and reliable.

With the self-diagnosis function of the power-on, some key hardware is self-checked, and the possible faults are reported immediately, so that the instrument is in the best working condition.

With a communication interface, the data and test results of the test process can be sent to the computer for display, saving and printing in real time.

The air pump and the stirring are automatically turned on to avoid human error, and it is extremely convenient to replace the desiccant.

The requirements of the use of sulfur analyzer 1. Turn on the power: press the power switch, the instrument will conduct self-test after power on, and automatically increase the temperature after the self-test passes.

2. When the furnace temperature rises to 1100°C, start the carrier gas system and check the air tightness. The method is as follows: The hemostatic clip is used to clamp the air inlet and the discharge tube of the electrolytic cell. At this time, the float of the gas flow meter should be seen to slowly decrease. If it falls below 500 ml/min, it means that it is qualified; otherwise, the problem should be checked and solved before continuing. Do experiments.

3, then open the liquid discharge tube and hemostatic clip, the electrolyte into the electrolysis cell, the electrolyte into the electrolysis cell, the electrolyte generally does not exceed 2 cm above the electrode plate. Adjust the stirring speed (in the case of the mixer without losing the step, the stirring speed is faster and better), and it is not allowed to change the stirring speed during the experiment, otherwise the experiment is invalid. Finally adjust the flow meter so that the airflow is about 1000ml/min. During the experiment, you should always observe the air flow. If it is too low, you should adjust it.

4, when the furnace temperature rose to 1150 °C, you can start experimenting. 1-3 waste samples must be made before testing official samples. If the electrolyte is not used for a long time and the color is very dark, it is better to use coal with high sulfur content as waste sample until the result is not zero and the electrolyte color becomes light. The purpose of the waste sample is to make the electrolyte meet the requirements of the instrument. Balanced state. A batch of samples is best done continuously, such as the middle break for a relatively long time (more than half an hour), in order to ensure accuracy, it is best to add a waste sample before continuing the experiment.

5. After the experiment is completed, turn off the carrier gas system, and finally discharge the electrolyte, and clean the electrolytic cell with distilled water.

6. Return to the main menu. The instrument with automatic shutdown function uses automatic shutdown. The other models of sulfur analyzer turn off the power switch and turn off the main power before off duty.

The total sulfur content of coal is one of the important indicators for evaluating coal quality, and it is also one of the main components of atmospheric pollution. Therefore, the coal production sector and the coal sectors such as chemical fertilizers, power generation, civil use, coking, and building materials all attach great importance to the analysis of total sulfur in coal.