Application of Venturi wet dust collector in the ceramic industry

With the continuous improvement of environmental protection requirements, the dust control issues generated in the ceramic industry during raw material crushing, batching, ball milling, spray drying, firing and post-processing have received more and more attention. The Venturi wet dust collector can capture and purify dusty waste gas by utilizing the joint action of high-speed airflow and spray liquid. It is one of the common wet dust removal equipment used in ceramic production waste gas treatment.

This equipment is suitable for processing exhaust gas conditions with high dust concentration and fine particles or where cooling and humidification are required at the same time. Whether it is suitable for specific use should also be selected based on dust properties, exhaust gas temperature, moisture content and emission requirements.

1. Working principle of Venturi wet dust collector

After dust-containing gas enters the Venturi tube, it is accelerated in the throat. The spray liquid is broken into fine droplets under the action of high-speed airflow, and collides, intercepts and condenses with dust particles.

Smaller dust particles combine with liquid droplets to form larger dust-containing liquid droplets, which then enter the gas-liquid separation device. Under the action of centrifugal force, gravity or mist removal structure, dust-containing droplets are separated from the air flow, and the purified gas is discharged from the outlet.

The collected liquid enters the circulating water tank or sedimentation area, and can continue to be recycled after sedimentation, filtration, sewage discharge and water replenishment. For waste gas containing acidic, alkaline or water-soluble gases, corresponding absorbing agents can also be added according to the nature of the pollutants.

2. Main application links in the ceramic industry

1. Raw material crushing and transportation: processing of particle dust generated during the crushing, screening and transportation of mineral raw materials.

2. Batching and mixing: Collect the dust generated during the feeding, weighing and mixing process of powder.

3. Spray drying: used for cooling, humidifying and particulate matter pretreatment of some high-temperature dusty exhaust gases.

4. Pretreatment of sintering waste gas: preliminary purification of dust and some water-soluble components in the kiln waste gas.

5. Grinding and post-processing: dealing with the fine dust generated during the cutting, grinding and trimming of ceramic products.

3. Main features of the Venturi wet dust collector

1. Strong collection ability for fine particles: high-speed airflow can increase the probability of collision between droplets and dust, and is suitable for processing some fine particles.

2. Can cool down and humidify at the same time: After the spray liquid comes into contact with high-temperature exhaust gas, it can reduce the gas temperature and increase the humidity.

3. Reduce secondary dust: after dust enters the liquid phase, it is not easy to fly again, which facilitates centralized treatment.

4. Adapt to high-concentration dust: With reasonable design and smooth sewage discharge, exhaust gas with high dust concentration can be processed.

5. Can be combined with the absorption process: By adjusting the circulating fluid formula, some acidic, alkaline or water-soluble pollutants can be treated at the same time.

4. Effect on ceramic production

The Venturi wet dust collector can reduce the concentration of particulate matter in the production area and exhaust gas, help improve the workshop environment, and reduce the impact of dust on equipment, pipelines and subsequent processing units.

For some high-temperature exhaust gases that need to be cooled, wet treatment can also reduce the heat load of subsequent equipment. After pretreatment, the gas can enter demisting, absorption, filtration or other subsequent purification equipment according to emission requirements.

It should be noted that whether the equipment can reduce the overall operating cost should be comprehensively evaluated based on system resistance, circulating water volume, sewage treatment and maintenance costs. Venturi dust collectors generally have a higher pressure drop, so the fan energy consumption is not necessarily lower than that of ordinary wet or dry dust collection equipment.

5. Regarding the treatment of harmful gases and VOCs

The main advantage of the Venturi wet dust collector is to capture particulate matter. Gases that are easily soluble in water or can react with chemicals can be removed to a certain extent by absorbing liquid.

For most VOCs that are poorly soluble in water, it is usually difficult to achieve ideal treatment results by relying solely on ordinary water spray. It is necessary to combine activated carbon adsorption, catalytic combustion, condensation recovery or other special organic waste gas treatment processes.

6. Main factors affecting the dust removal effect

1. The air flow velocity at the venturi throat and the system pressure difference.

2. Spray liquid volume, droplet size and nozzle arrangement.

3. Dust particle size, concentration, density and hydrophilicity.

4. Exhaust gas temperature, humidity and corrosiveness.

5. The operating status of the gas-liquid separator and mist removal device.

6. The concentration of suspended solids, sludge and chemicals in the circulating fluid.

7. Parameters that need attention when selecting equipment

When ceramic companies select Venturi wet dust collectors, they should provide complete working condition parameters based on the production process and emission requirements.

1. Actual processing air volume and equipment operating time.

2. Dust type, particle size, concentration and abrasiveness.

3. Exhaust gas inlet temperature and moisture content.

4. Whether it contains acidic, alkaline or organic pollutants.

5. Allowable system resistance and fan power.

6. Circulating water treatment, sewage discharge and sludge disposal conditions.

7. On-site installation space, interface direction and material requirements.

8. Precautions for operation and maintenance

1. Check the nozzle and throat regularly to prevent clogging and wear.

2. Clean the circulating water tank, sedimentation tank and sewage pipes regularly.

3. Check whether the gas-liquid separator and mist eliminator are blocked.

4. Monitor system pressure difference, air volume and circulating fluid level.

5. Timely replenish water, add medicine and discharge sewage according to the status of circulating fluid.

6. Regularly inspect and promptly repair parts with strong corrosion and wear.

9. Equipment application suggestions

The Venturi wet dust collector is suitable for high-concentration dust, fine particle pretreatment and high-temperature exhaust gas cooling in the ceramic industry, but not all working conditions are suitable for wet treatment.

For production lines that are not allowed to produce waste water, where dust tends to agglomerate when exposed to water, or where dry powder materials need to be recovered, priority can be given to bag dust collectors, cartridge dust collectors or other dry purification equipment.

The actual treatment effect and energy consumption of the Venturi wet dust collector are closely related to the throat speed, system pressure difference, spray volume, gas-liquid separation efficiency and sewage treatment method. Before equipment selection, calculation and design should be carried out based on the complete working conditions.