As the mainstream dry dust removal equipment in the industrial field, the advantages and disadvantages of bag filters are deeply related to filtration principles, structural design, and application scenarios. The core advantages are concentrated in filtration accuracy, adaptability, and other aspects, while the disadvantages are mostly related to working conditions limitations and operating costs, as follows:

1、 Core advantages (core competitiveness in industrial applications)

1. Extremely high filtration accuracy and strong ability to meet emission standards

Core advantage: With the help of filter bag fiber interception and secondary filtration of dust in the initial layer, it can effectively capture fine dust above 0.1 μ m, with a stable filtration efficiency of over 99.99%, and can easily meet ultra-low emission requirements (such as the dust emission concentration ≤ 10mg/m ³ in Chinas GB 13271-2014 standard, which can achieve ≤ 5mg/m ³ in some scenarios);

Applicable value: Especially suitable for industries with strict emission requirements (such as electricity, metallurgy, chemical industry), or scenarios containing fine dust (such as catalyst recovery, welding fume treatment).

2. Wide adaptability and strong compatibility with working conditions

Dust concentration adaptation: It can handle gases with inlet dust concentrations ranging from 10-1000g/m ³ (high concentration scenarios require pre dust removal with a cyclone dust collector), suitable for both low concentration exhaust gas purification and high concentration dust recovery;

Dust characteristics compatibility: It can handle dry, non sticky or low sticky dust (such as fly ash, cement powder, metal oxides), and some special filter bags (such as PTFE film) can handle slightly sticky dust;

Temperature/corrosion resistance: Conventional filter bags (polyester) can withstand 80-120 ℃, high-temperature filter bags (PPS, Fumes) can withstand 160-260 ℃, and corrosion-resistant filter bags (PTFE) can deal with corrosive flue gas containing acid and alkali (such as chemical tail gas, metallurgical smelting flue gas);

Flexible air volume regulation: Modular design enables customization of air volume from several thousand to several hundred thousand m ³/h, suitable for small workshops to large industrial facilities such as cement kilns and blast furnaces.

3. High dust recycling value, win-win situation for environmental protection and economy

Recyclable valuable dust: such as metal oxide dust from the metallurgical industry, catalyst powder from the chemical industry, flour/feed powder from grain processing, and unattached coatings from powder coating. After recycling, they can be reused as raw materials to reduce losses;

Good dust collection effect: The design of the ash hopper and ash unloading device can efficiently collect dust, avoid secondary pollution, and the collected dust has a low moisture content (dry dust removal), making it easy to store and dispose of.

4. Mature structure and easy maintenance

Modular design: composed of multiple filter bag chambers, it can achieve "offline cleaning" (cleaning of a certain filter bag chamber does not affect the overall operation), or not interrupt the overall dust removal system during single chamber maintenance;

Low maintenance cost: The filter bag replacement operation is simple (disassembled through the inspection door), and the service life of the filter bag is 1-3 years under normal working conditions. The vulnerable parts (pulse valve, unloader) are highly versatile, and procurement and replacement are convenient;

Stable operation: High degree of automation (PLC control for dust cleaning and unloading), no need for dedicated personnel to be on duty in real time, low failure rate.

5. No secondary pollution, environmentally friendly

Dry dust removal does not require water, avoiding the sewage and sludge treatment problems generated by wet dust collectors, especially suitable for water scarce areas or scenarios with high water quality protection requirements;

No wastewater discharge, dust collection can be disposed of in compliance with regulations (such as landfill, incineration, recycling), and will not cause water or soil pollution.

2、 Main drawbacks (application scenario limitations and operating costs)

1. Sensitive to working conditions and subject to application limitations

Not resistant to high temperature and high humidity: exceeding the temperature tolerance of the filter bag (such as regular polyester bags>120 ℃) will cause the filter bag to melt and accelerate aging; Excessive moisture content in flue gas (above dew point) can easily lead to dust condensation and adhesion to the surface of filter bags, causing "bag sticking" (filter bag blockage), requiring additional insulation or heating devices;

Not resistant to high viscosity dust: When dealing with highly viscous and hygroscopic dust (such as cement raw material powder, coal powder+water vapor mixed dust), the dust is prone to adhere to the surface of the filter bag, making it difficult to clean, resulting in a sharp increase in resistance, and even inability to operate normally;

Anti static/explosion-proof design is required: When dealing with flammable and explosive dust (such as coal powder, wood powder, and grain powder), anti-static filter bags, explosion-proof valves, and explosion-proof devices need to be installed to increase initial investment.

2. High pressure loss and high energy consumption

Filtering resistance: During normal operation, the resistance is 1200-1500Pa, but after cleaning, it drops to 800-1000Pa, which is higher than that of cyclone dust collectors (resistance 500-800Pa) and electrostatic dust collectors (resistance 200-300Pa);

Fan energy consumption: To overcome high resistance, it is necessary to configure fans with higher power, which results in higher electricity costs for long-term operation (especially in high air volume scenarios).

3. The equipment has a large volume and occupies a wide area

The filtering wind speed is relatively low (usually 0.8-1.5m/min), and in order to achieve the same processing air volume, a large number of filter bags are required, resulting in a large equipment volume and high steel consumption;

Compared to electrostatic precipitators (compact designs), bag filters typically occupy 30% -50% more space and are not friendly for renovating old factories with limited space.

4. High operating costs and initial investment

Initial investment: The cost of filter bags (especially high-temperature and corrosion-resistant materials) is relatively high (for example, the unit price of PTFE filter bags is 3-5 times that of polyester bags), coupled with the box, dust cleaning system, fan, etc., the overall investment is higher than that of cyclone dust collectors and slightly lower than that of high-end electrostatic precipitators;

Operating costs: The filter bag needs to be replaced regularly (1-3 years/time), plus compressed air (for pulse cleaning), fan electricity fees, and long-term operating costs are higher than those of cyclone dust collectors;

Maintenance workload: Although maintenance is convenient, filter bag replacement, pulse valve maintenance, etc. still need to be carried out regularly, especially in high dust concentration and harsh working conditions, where maintenance frequency will increase.

5. Low temperature environments are prone to condensation

When operating in winter or low-temperature areas, if the flue gas temperature is close to the dew point, it is easy to condense inside the box and ash hopper, causing dust agglomeration and blockage of the ash discharge device (such as star shaped unloader jamming). It is necessary to install a heat tracing device or strengthen insulation to increase additional energy consumption and investment.