1. What are the dust prevention measures for refractory plants?During the production of refractory materials, a large amount of dust is generated. In order to minimize the generation of dust and avoid workers' contact with dust, the following comprehensive measures can be taken:
1) Reduce dust concentration with reasonable production processes;2) Realize operation mechanization and automation to improve working conditions;
3) Strengthen organization and management and improve the dust protection system.
The specific measures for dust prevention are as follows:1) Humidification of materials can significantly reduce dust generation. Materials that can be humidified are silica, hard clay, high alumina, clinker, waste bricks, and so on. The amount of humidification allowed for various materials is different, mainly depending on the following factors: the maximum moisture content of the material; the initial moisture content of the raw materials; the production capacity of the equipment during operation; the evaporation of moisture in each step of the processing process; the formation of various bricks Moisture.
2) Sealing of equipment The sealing of equipment is to limit the dust to a local area and create conditions for suction and dust removal. The closed forms of equipment often used in the production of refractory materials can be divided into the following types:(1) Partially closed hood: the part of the equipment that dusts is enclosed in the hood, which is suitable for dust sources that are concentrated and continuously dusted and that are not pressurized at an instant. The characteristic of the local closed cover is that the entire sealing cover needs to be removed when servicing the equipment, so it is generally used in places where the equipment is not frequently repaired, such as the inlet of a barrel mill.
(2) Semi-closed hood: All equipment is enclosed in the hood except the transmission part, with observation holes and operation doors left. This kind of airtight cover is suitable for the equipment that is full of dust, such as dry mill. Its characteristic is that the product processing is carried out completely in the closed hood, the operator operates outside the hood, the workers can enter the hood for maintenance when the vehicle is stopped, and the closed hood must be removed when the equipment is overhauled.(3) Integral airtight cover or small airtight room: All dusting equipment is enclosed in the cover. For dusting equipment with frequent maintenance and inconvenient use of semi-closed cover, this type of closed type can be adopted, such as vibrating screen. Its characteristic is that the product processing is performed inside the hood, and the operator can enter the hood for maintenance at any time, and there is no need to remove the closed hood when the equipment is overhauled.
2. What are the requirements for the equipment's closed cover structure?
The equipment enclosure structure should meet the following requirements:
1) The structure should be solid and tight, and the joints of the closed enclosure should not lose its tightness due to equipment vibration and block collision.2) Do not affect the normal operation of workers, and should keep operating doors.
3) Fully consider the convenience of the equipment during maintenance, and leave necessary inspection holes.4) The size of the holes and doors on the airtight cover should meet the minimum requirements.
3. What parts does the dust removal device include?Dust removal devices include dust suction devices (suction hoods or dust suction nozzles), dust-containing gas transportation pipes, dust and gas separation equipment (various types of dust collectors), and exhaust gas purification devices ( Exhaust fan) and other parts.
4. What are the basic matters to consider when selecting dust removal equipment?
The following points should be considered when selecting dust removal equipment:
1) Dust properties: the origin and status of the dust, the amount of dust and its concentration; the properties of the dust (chemical composition, particle size, density, temperature, moisture absorption, charged status, dust characteristics (harmful gases, radioactivity) Wait);2) dust recovery method or treatment method;
3) The degree of dust removal that is expected, that is, the concentration of imported dust and the concentration of outlet dust;4) Cost, that is, the investment amount of the dust removal equipment, the occupied space, the necessary power costs, maintenance, and management costs required for operation. For example, when selecting a wet dust collector, the water consumption and the subsequent disposal and recovery of mud should be considered.
In practice, the dust collector should be selected according to the following conditions:
1) Cyclone dust collectors can be used for ordinary occasions. If the dust cannot be separated sufficiently, a bag dust collector can be used in the rear section.
2) The cyclone dust collector is most suitable for coarse granular dust. The fine powder generated by abrasion can be separated by attaching a bag filter afterward.
3) When the particle size of the dust is mostly less than 3 / um, it is difficult to catch with a cyclone dust collector. A bag dust collector or a wet dust collector can be selected.4) In the case of dust slurry recycling or disposal, various wet dust collectors can be used.
5. What are the reasons for the clogging of the dust removal pipe?
The reasons for the clogging of the dust removal pipeline are as follows:
1) The material generates heat during processing to evaporate the moisture contained in the material. Water vapor is sucked into the dust removal pipe and is cooled and condensed into water, which is attached to the pipe wall to adhere to the dust and gradually block the pipe.
2) When the inclination angle of the pipeline is lower than the repose angle of the dust (25 ° ~ 50 °), the dust in the pipeline will not slide off by itself and cause a blockage.3) The air velocity in the pipe is too small so that the dust cannot stay in the horizontal pipe with the airflow and cause the pipe to be blocked.
6. What types of dust removal equipment can be divided into?
Dust removal equipment can be divided into four types according to the nature of the force:
1) Dust reduction chamber: Dust is settled due to gravity.
2) Cyclone dust collector: The dust is settled by using the centrifugal force generated by the dust-containing airflow during the rotary motion.3) Filter type dust collector (bag type dust collector): The dust-containing airflow is purified by filtering, and the dust particles are trapped because they are blocked and stuck.
4) Electrostatic precipitator: The dust is charged under the action of a high-voltage electric field and moves to the electrode carrying the same charge, and then is neutralized and lost the charge and is captured.
According to the working principle, the dust collector can be divided into two types: dry dust collector and wet dust collector.According to the degree of purification can be divided into three categories:
1) Coarse purification: Capable of capturing dust particles above 100 / um, and its efficiency is above 90%. For multi-stage purification of high-dust-concentration gases, rough purification can only meet the first-stage purification requirements.
2) Medium purification: Capable of capturing dust particles of more than 10um, and its efficiency is more than 90%. When the dust in the gas is mainly composed of coarser particles and the dust concentration is not greater than 2g / m3, the requirements can be met by a first-stage purification dust removal equipment.3) Fine purification: Capable of trapping dust particles above lum, its efficiency is above 90%. When the dust in the gas is mainly composed of coarse particles, fine purification equipment can be used when the dust removal efficiency is required to be above 98%.
The dust removal principle of the cyclone dust remover is: the dust-containing gas enters the cyclone dust remover and rotates to generate centrifugal force. Due to the difference in the density of dust and gas, the two are separated. Therefore, the centrifugal force is large, the particle size of the dust is large, and the concentration is large, and it is easy to separate.The advantages of cyclone dust collectors are simple structure, easy manufacture, cheap price, small floor area, and high dust removal efficiency. The disadvantage is that it has low purification efficiency for fine particles below 5 ~ 10um.
8. What are the characteristics of a bag filter?Baghouse is purification equipment that uses organic fiber or inorganic fiber cloth to filter out the dust in the gas. It is suitable for handling non-adhesive and non-fiber dry industrial dust. Its advantage is that the dust removal efficiency is high, the dust below 5um can reach more than 99%, compared with the wet type dust collector, the dust is easy to recycle and does not need winter antifreeze. The disadvantage is that the filter cloth consumes more, and the cost is higher than that of wet dust removal equipment. When the gas contains water vapor and handles hydrophilic dust that easily absorbs water, the dust adhered to the filter cloth can easily cause blockage, and it is not suitable for processing high-temperature dust-containing gas.
9. What is the dust removal principle of the electric dust collector? What are the advantages and disadvantages?
The dust removal principle of the electric precipitator is to use the corona discharge to charge the dust particles, and the charged dust particles are collected on the dust collecting pole under the action of static electricity.The advantages of the dust collector are: high dust removal efficiency, in principle, all dust in the gas can be removed; less energy consumption, processing 1000m3 gas consumes about 0.1 ~ 0.8kW / h; can handle high temperature and corrosive gas; operation process Can be fully automated. Its disadvantages are that it is expensive to manufacture and requires special devices that supply very high DC voltages (35,000 to 70,000 V) and a high level of technical management.
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