|Fluid bed dryer, basic fluidized bed works based on, the material of the drying process is based on boiling powders. In the exhaust under the fine powder within the container trap bag filter back row to the outside, the trapping process there are a large number of ultra-fine powder to produce, whether it is boiling in the flow or trap run the whole process of boiling dry with ultra-fine powder movement. However, the process of powder movement is often accompanied by two problems with static electricity and dust explosion under the guidance of some of the factors to cause an explosion phenomenon.
At present, when dealing with such issues as long as the placement of the explosion-proof motor can be OK, it is considered defective. Theory of boiling from the powder electrostatic and dust explosion, explosion-proof security for the fluid bed dryer to put forward their point of view, the purpose of such equipment manufacture and application of more complete, more reliable and safer.
A fluid bed dryer powder boiling of static electricity generated by factors of
Intense friction materials, due to the drying gas and the surface of the material particles in a fluid bed dryer boiling dry of dry solid particles also have a dramatic impact and friction between solid particles and the cylinder wall, trapping bags and tubes violent collision and friction of the road wall, making the solid particle surface with a lot of static electricity; the other hand, with continuous refinement of the solid particles, generated a lot of freshmen surface, the surface charge of the original particle equilibrium is destroyed, so that The new particle surface to bring a lot of charge. Aggregation, adhesion to the wall as soon as the machine ground state is bad, allows the accumulation of electrostatic charge to the formation of a very high voltage, under certain conditions, will lead to electrostatic discharge resulting spark. Has been dry material is flammable and explosive materials, such a static spark can easily cause a sudden fire or explosion of the dry material.
The powder in the fluid bed dryer boiling caused safety problems, the literature powder easy to produce two types of hidden prevention made certain described as a fluid bed dryer can be used for the following reference.
Boiling dryer anti-static measures
Powder boiling fluid bed dryer to prevent static electricity can learn the following measures:
1) the trap bag anti-static fiber material in a timely manner to eliminate the static on the powder into the bag, to avoid stripping from the electric powder Poly Manifold off.
2) conductor material for the air supply pipe and the connecting parts to connect the entire system and carefully connected electricity, electrostatic powder on a timely guide to go.
3) other methods, such as increasing the diameter of the pipe to reduce the elbow, regular cleaning and discharging operations workers wear anti-static clothing operation, etc., electrostatic suppression, reduction and elimination of powder boiling process is also effective.
(2) factors of dust explosion in the fluid bed dryer
The dust explosion is defined as the dust particles suspended in the air is full contact with the oxygen in the air, to complete the oxidation reaction under certain conditions, instantaneous reactions release a lot of heat, resulting in high temperature, high pressure phenomenon. In general, the combustible solid in the air when burned, release energy and produce large amounts of gas, releasing the energy of the speed of burning speed and the size of the area exposed to the air of solids (dust). Therefore, the powder of the same kind of solid material, the smaller the particle size than the larger the area, the faster flame spread. Solid particle size is very small, as well as can be suspended up, once the ignition source ignited a lot of energy can be released within a very short time, the energy was too late dissipation into the surrounding environment, resulting in the space the gas by heating and expansion of the absolute, while on the other hand, the powder burning large amounts of gas, the system will form a local high pressure, as well as to produce an explosion and dissemination.
Of boiling dry powder of insecurity
Because regardless of the flow boiling or in the trap run, the material in the fluid bed dryer boiling can easily produce large amounts of dust, dust boiling can easily result in the above-mentioned static spark that could cause an ignition source elements. For the "dust cloud", as the literature described in the "combustible powder particles greater than 400μm, the formation of dust cloud is no longer can be explosive." And when the powder particle size less than 10μm, have a greater risk of "capture fluid bed dryer bags and the discharge pipe between the particle size of fine, most likely the" dust cloud ". Therefore, the general material on the very likely the existence of the factors of dust explosion with combustible powder components, it means to have the three elements of the dust explosion, such as material if the possibility of dust explosion.
If only in a fluid bed dryer equipped with explosion-proof motor, to prevent ignition sources on the basis of its such a device must be configured. The above, static electricity and dust explosion explosion-proof security of such equipment, its often forgotten, while the actual drug production to ensure the safety of production equipment, reliable and in accordance with the requirements of the corresponding process. It is not just by the past of such an accident, this need not be too serious, "the concept to manufacture such equipment should be scientific and security to consider.
Boiling dryer anti-dust explosion, measures
Powder in the boiling dryer boiling to prevent anti-dust explosion can learn the following measures:
1) removal of ignition sources, the possible sources of ignition equipment and devices should be installed in explosion suppression system, explosion-proof membrane or pressure relief valve set in dust or Lvchen equipment and pipe.
2) often remove the pipe and trap dust bag, no dust accumulation.
3) electrical equipment, explosion-proof device, such as explosion-proof motor, installation of ground.
4) plant designed to meet the requirements to prevent dust explosions, according to antiknock design, and have adequate explosion relief area.