Application of pulse jet bag filter on dryer (1)

Clay, iron powder, coal, ore (steel) slag are materials that are often required to be dried in cement production. The characteristics of exhaust gases generated during the drying of different materials are different, but generally have the following characteristics:

1 The exhaust gas contains a large amount of moisture, and has a large fluctuation range. The water content is above 15%. Higher moisture content leads to strong adhesion of dust particles and is not easy to remove dust.

2 High dew point temperature, up to about 60°C. Condensation can easily occur under the intermittent operating conditions of the cement plant drying system.

3 The dryer has a high concentration of dust gas at the outlet, more than 50g/m3, and often exceeds 100g/Nm3 when baking clay. Dust particles such as mine (steel) slag have strong abrasion to the filter body and filter bag.

4 The exhaust gas tends to be corrosive, not only harmful to the dust collector but also damaging the filter bag.

5 Under normal conditions, the exhaust gas temperature is between 100°C and 120°C. Under abnormal conditions, the temperature is much higher than 120°C and even 160°C to 200°C.

Dryer Bag Dust Collector Status
The blowback dust bag filter developed in 1990 is the most commonly used dryer dust remover in cement plants. The glass fiber material treated with hydrophobic water is used as the filter material and the internal filter method is adopted. The working principle is as follows: dusty flue gas enters the air intake chamber from the upper part of the dust collector, part of the coarse particles falls into the ash bucket due to inertia, and other dust particles enter the air intake chamber through the air intake branch through the flue gas, and evenly pass through the upper flower board. Chung filter bags, a large number of dust stuck in the filter bag, part of the dust directly through the lower plate into the ash bucket. The purified gas is discharged through the exhaust valve. When the dust layer adhered to the inner surface of the filter bag is thickened to a certain degree, the operating resistance of the dust collector increases to a certain value. The control system activates the reverse blower to perform the chamber cleaning process, and the air blowing changes the pressure difference inside and outside the filter bag. The filter bag expands to deflate, removes the dust layer attached to the inner surface of the filter bag, so that the dust remover returns to normal operation, and the dropped dust is discharged into the conveyor through the lock air discharge valve.

The design performance indicators of the back-flush dryer dust collector are: the filter wind speed ≤ 0.5m/min, the outlet discharge concentration ≤ 100mg/Nm3, and the equipment resistance ≤ 1700Pa.

After the implementation of the "Emission Standard of Air Pollutants for the Cement Industry" (GB4915-2004) on January 1, 2005, the dust emission concentration of the cement plant is limited to ≤ 50mg/Nm3. In addition to the discharge concentration of the dust collector of the reverse-blowing dryer, which cannot meet the standard, other insufficiency specifically shows:

1 The lack of kinetic energy to clean the ash, which limits the use of many high-quality filter materials, can only be selected with glass fiber cloth filter material, which has low filtration speed, large volume, and high steel consumption.

2 The restriction of the air intake method and the filtering method makes it difficult to evenly distribute the exhaust gas load to each bag room, and cannot treat exhaust gas with high concentration of dust. The kinetic energy distribution of the cleaning dust is uneven, resulting in large equipment resistance and short filter bag life.

3 Blowback dedusting brings in a large amount of cold air, which intensifies the condensation of the equipment.

4 The filter bag is bundled and installed. The filter bag is prone to wear, and the dust is easy to pass through in the banding installation area.

5 The inner filter method causes the dust particles with high hardness to cause serious wear on the bag mouth, which reduces the life of the filter bag.

Features of GMC Pulse Jet Bag Dust Collector

GMC pulse jet bag filter is divided into two types: off-line cleaning and on-line deashing. Its working principle is as follows: dust-containing gas is pre-dedusted by pre-dust collection device, and then passed through dust collector hopper (inline cleaning type directly into hopper , The off-line deashing type of the compartment enters the bag room from the butterfly valve and the inlet pipe into the dust collector hopper. The dust stays on the outer surface of the filter bag (external filtration type). The filtered clean gas is discharged from the bag mouth to the purging chamber and discharged. . Whenever the dust collector reaches a certain value at a certain time or when the resistance of the dust collector reaches a certain value, the dust gas is pulsed by the pulse valve, so that the compressed air in the air packet is sprayed from the blowhole (or nozzle) in the net chamber to generate the dust gas. Source, clean air source induced clean air in the clean air room to generate clean air (secondary air flow) which is several times the clean air source (primary air flow) into the filter bag, making the filter bag expand rapidly in the instant, When the "star shape" of the filtration process expands to the extreme position of a circle, a strong shock is generated due to the great tension, and the filter bag obtains the maximum reverse acceleration during the deformation movement and then starts inward. Contraction returns to a free, normal state. During this process, the filter bag exterior finishes the dust stripping. After the cleaning process is completed, the filter bag continues to be put into the next filtration cycle.

Hydraulic reversing valve

Hydraulic Reversing Valve,Directional Valve,Manual Directional Direction Valve,Directional Valve Solenoid

Huai'an Aide Hydraulic Machinery Co.Ltd , https://www.aidepump.com