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How to choose filter bags better in different working conditions of iron and steel plants

There are different working conditions in different processes of the iron and steel plant, so there are also differences in the selection of filter materials for the dust bag.

Coking:

The temperature of coking flue gas is around 90 ℃, and the instantaneous temperature can reach 130 ℃. The flue gas contains sulfur and less water.
According to the different parts of the process, the performance requirements of the filter bag are also different. For example, coking and dust removal require anti-static and flame retardant, coke table, and CDQ dust removal require anti-static, and screen coke dust removal require waterproof, oil-proof, and anti-static.
After years of use, it has been proved that the use of PTFE-coated polyester needle felt as the filter bag can meet the requirements of flue gas capture in terms of performance, and the particulate emission concentration is basically controlled at 10mg / m3 ~ 20mg / m3, which can meet the new emission standards Special emission limits.

Sintering:

The flue gas of the sintering machine head is generally equipped with dry, semi-dry and wet desulfurization systems after electric dedusting. Among them, the bag type dust removal needs to be configured after the semi-dry desulfurization system. (About 90 ℃) and composition (a small amount of SO2, NOX, dust) The bag-type dust removal using PTFE-coated polyester needle felt as the filter bag can effectively ensure the discharge according to the standard.
The sintering machine tail, flux, ingredients, and whole-grain dust removal are currently using electric dust collection for flue gas capture. In order to meet the special emission limit of 20mg / m3, electric dust removal can be changed to bag dust removal. Emission concentration analysis, using PTFE-coated polyester needle punched felt as the filter bag, the emission concentration can be maintained at about 10mg / m3.

Blast furnace ironmaking:

According to the characteristics of blast furnace flue gas, all blast furnace flue gas dedusting uses water-proof and oil-proof PTFE coated polyester needle felt to make filter bags, and the particle emission concentration can basically be controlled within 10mg / m3, which can meet the country New air pollutant special emission limit requirements;
The main components of blast furnace gas are CO, CO2, N2, H2, CH4, and the combustible component CO accounts for about 25%. At present, it is purified by dry dust removal. Because its continuous operation flue gas temperature reaches above 200 ℃, high-temperature resistance must be selected the glass fiber or P84 (polyimide) is used as the filter material. However, after actual use, the glass fiber filter material is easy to break and has a short life. It is expected that the service life can reach 3 years under normal conditions, and the particulate matter emission concentration is steadily controlled at about 3 mg / m3, which can fully meet the production needs.

Electric furnace:

At present, the three-stage collection method of four-hole, dog kennel, and roof cover is adopted for the dust removal of an electric furnace. The high-temperature flue gas and the normal temperature flue gas are reasonably mixed, which effectively reduces the temperature of the flue gas at the entrance of the dust collector.
However, considering the unexpected situation, the instantaneous flue gas temperature may reach above 200 ℃. Therefore, the use of PTFE-coated Metas filter material can not only reduce operating costs but also effectively capture flue gas and efficiently filter to ensure that the particulate matter emission concentration is controlled at 10mg / m3 or less.
Of course, in the actual application on-site, there is a short pipeline between the collection hood mouth and the dust collector inlet due to space limitations. The high-temperature flue gas will enter the dust collector in a short time, and a large number of dust bag burns. At this time, the dust collector uses glass fiber filter material, which can effectively avoid such accidents.

Converter:

The secondary flue gas of the converter belongs to the normal temperature range. The PTFE-coated polyester needle felt is used as the filter bag. The emission concentration can be maintained at about 10mg / m3, which can meet the new particle emission concentration requirements.
The AOD refining process belongs to the reduction reaction process. If the furnace body flue gas and the roof hood flue gas are collected separately, the furnace flue gas temperature is high and alkaline, and there are water-cooled flue leaks. The material must have the characteristics of waterproofing and alkali resistance, and the PTFE-coated Metas filter material can be used, which is both waterproof and has the characteristics of alkali resistance and high-temperature resistance.
The dust removal of the roof cover uses PTFE coated polyester needle felt to make the filter bag, which can meet the collection and discharge requirements. If the furnace flue gas and roof flue gas are mixed and then collected into a dust collector, due to the mixing effect of the roof flue gas at normal temperature, the flue gas temperature at the inlet of the dust collector can meet the normal temperature requirements, so PTFE coated polyester needle felt Filter bag is enough.

Dust removal in other environments. Generally, in the case of drying and flue gas temperature below 100 ℃, the filter material of the environmental dust collector should use PTFE coated polyester needle felt as the filter bag.

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