Application of dust collecting equipment in cement factoryDate: 2019-06-21 Views:
Simple analysis of several existing dust collection equipment in cement plant is as follows:
1. Difficulty in smoke and dust control
The main dust source of cement factory is crusher, rotary dryer, vertical dryer, raw material mill, powder separator, cement mill, vertical kiln, packaging machine and so on.
In addition, conveying equipment, storage top and bottom conveying, inlet and outlet are dust sources that generate post dust.
Among them, it is difficult to control the exhaust gas of vertical kiln.
The smoke and dust treatment of vertical kiln is difficult mainly in the special working condition of "wet, corrosion and change" of its smoke, not because of its large smoke volume (much smaller than the exhaust gas volume of rotary kiln tail), nor because of its high dust concentration (vertical grinding and 0-sepa powder separator's emission concentration is dozens or even hundreds of times higher).
"Wet" refers to the smoke containing large amount of moisture (8% ~ 20%), high dew point temperature (40% ~ 55%), and higher acid dew point temperature.
"Corrosion" means that the corrosion of fluoric acid is especially strong after adding compound mineralization agent.
"Variable" refers to the frequency variation and wide range fluctuation of parameters such as exhaust gas volume, dust content (1 ~ 30g/Nm3), temperature (45 ~ 450°C), humidity and dust specific resistance value (109 ~ 1012Qni) with process operating conditions.
2. Several existing dust collecting technologies of vertical kilns in China
Domestic products in various forms, in addition to the settlement chamber, there are a variety of wet dust removal, electric dust removal and bag dust removal.
Wet dust removal: spray, water spray, water film, ultrasonic, swirl, self-excitation, water bath, compound, etc.
Electric dust removal has dry horizontal, vertical, vertical pipe rotary umbrella type, wet vertical, hydropower and other types;
The method of bag division includes the glass fiber bag dust collector (with upper and lower air inlet) which USES the reverse blow to clean the dust, and the low-pressure long bag box pulse dust collector which USES the pulse to clean the dust.
From the point of view of current development, efficient bag and electric dust collection technology is still the mainstream of application.
3. Discussion on several dust collecting technologies
(1) water dust removal
The biggest advantage of water dust removal is to adapt to the dark fire combustion process of modern vertical kilns, and has a strong adaptability to variable working conditions, not afraid of dust adhesion, and desulfurization, defluorination effect.
It is simpler to make and less expensive.
However, it is difficult to reach the standard of water dust removal, and high resistance, large water consumption, easy to cause secondary pollution, mud solution has a strong corrosive, even if the mud M into a ball disc and form potassium, sodium enrichment and affect the quality of clinker, at the same time the discharge of water mist diffuse, smoke vast.
Environmental protection departments in some developed areas have banned it.
(2) settlement chamber dust
The advantages of dust removal are simple structure, the least investment, and no need for special management, the least consumption of electricity.
The disadvantage is that it can only settle coarse particulate dust, which generally accounts for more than 60% of the dust size below 50m is difficult to capture, far from meeting the emission requirements.
(3) water, electricity compound dust
Because the first level of water dust removal caused secondary pollution and other problems still exist, and the second level of electric dust removal to prevent condensation, corrosion and water mist removal task is difficult, if the single electric field is impossible to achieve no smoke emission