The effect of oxygen content on electrostatic defocusers

The oxygen content cannot be high; high levels can easily lead to explosions

Excessive oxygen levels pose a risk of explosion; alarm interlock devices can be installed as a precaution!

2.1.3.11 Electrostatic precipitators a. A separation device should be installed at the inlet of the electrostatic precipitator and after the scrubber tower； b. The electrostatic precipitator should be equipped with an explosion vent valve ； c. The electrostatic tar catcher shall be equipped with a device that can cut off the power supply when either of the following situations occurs ； The oxygen content in the gas reaches 1% ； The gas pressure is below 50 Pa (5.1 mmH2O) ； The temperature of the steam-insulated insulated box is below the specified value (generally not lower than the gas inlet temperature plus 25°C). d. The electrostatic tar catcher shall be equipped with a vent pipe and a steam pipe ； e. Insulation or heating devices should be installed at the bottom of the electrostatic tar catcher ； f. Connection pipes with valves should be installed between the sedimentation tubes of the electrostatic tar catcher ； The above content is taken from the \"Regulations on Gas Safety in Industrial Enterprises\" =N420031986002. The following information is for reference only: In actual use, the maintenance and operation of online oxygen concentration detectors for electric coke capture are rather complicated. When using conventional online detectors and placing the sampling tube at the entrance of the electrostatic precipitator, the sampling tube is prone to being clogged by residues such as tar. The vast majority of users place the sampling tube after the electrostatic precipitator outlet (many papers indicate that specific measures can be taken to address this issue, such as automatic purging). Personally, I don’t think it’s reliable; I’ve worked with many instrument manufacturers, and none are confident that such a device can be installed in front of the furnace. There are non-contact laser oxygen meters that can be placed directly in front of the electrostatic precipitator, with nitrogen used for protection. It is very suitable for users with nitrogen needs; if a matching molecular sieve nitrogen generator is used, the part most likely to encounter problems during operation is the nitrogen generator itself. It is essential to maintain a positive pressure during the operation of the electrostatic precipitator (the same applies to the gas transmission system)! In a positive-pressure environment, even if an explosion occurs, it is relatively mild; once the blast passes through the explosion-proof membrane (blast vent), serious accidents to equipment or personnel generally do not occur. (In some companies, oxygen meters are merely for show, used to meet inspection requirements, and they still dare to use them in a positive pressure environment.)

What is the reason why high oxygen content causes explosions?

When the oxygen content in semi-water gas is high, an explosive gas is formed; two of the three elements necessary for an explosion are already present； Electrostatic defouling removes tar from the electrode wires through discharge; sparks are generated during this discharge, and these sparks can cause explosions when in contact with gas containing high levels of oxygen. 5# waiwailuo

What percentage of O2 gas is required to form a mixed explosive gas with approximately 70% CO+H2 in semi-water gas? Which sea friend can give an introduction?

If the oxygen content is too high, an explosion will occur. Non-contact oxygen meters, such as laser oxygen meters, are, from what I know in practice, hardly usable before the electrostatic dust removal of semi-water gas. We have used it. The oxygen meter can be put into operation before the semi-water gas is passed through the electrostatic precipitator. The sampling tube of the oxygen meter must be inserted halfway into the process pipeline, and certain measures must be taken for this tube; we cut a 45° bevel at the front end of the sampling tube in the direction opposite to the flow of air. The pretreatment device must also be properly equipped with desulfurizing agents to prevent poisoning by silica gel. Filters must also be configured, preferably with two levels of filtering. Now, I replace the silicone in the oxygen gauge of my device every week or so. The maintenance volume is not large.

There is a risk of explosion; it’s best to install an interlock device set at 1%. In my experience, the value is usually below 0.2% in normal situations.

A high oxygen content can easily lead to explosion accidents. Our factory’s practice is to immediately shut down the electrostatic decanter when the oxygen content exceeds 0.5%, and restart it once the oxygen level drops. If the oxygen content exceeds 0.8%, the entire plant must be shut down for treatment.