Modern chemical technology is associated with grinding, crushing, transportation of various materials. Part of them is converted into an aerosol form during processing, the dust formed together with ventilation and process gases enters the atmosphere. Consider the basics of chemical technology currently used in production.
Devices for cleaning dust from gaseous substances
Dust particles have a high total surface; as a result, they exhibit increased biological and chemical activity. Part of the substances in the aerodispersed form, new properties appear, for example, they are able to spontaneously explode. There are various chemical technology apparatuses used to clean the gaseous substances formed in the production of dust particles of various sizes and shapes.
Despite significant differences in design, the principle of their action is based on the delay of the suspended phase.
Cyclone and dust collectors
Analyzing the various processes and apparatuses of chemical technology, we dwell on the group of dust collectors, which include:
- rotary dust collectors;
- cyclones;
- louvre models;
- dust precipitation chambers.
Among the advantages of such devices, we note the simplicity of their design, so that they are produced in non-specialized enterprises.
As a minus of such devices, professionals note a lack of effectiveness, the need for repeated cleaning. All types of dust collectors operate on the basis of centrifugal forces, differ in power and speed of deposition of dust particles.
For example, the classical chemical technology for the production of sulfuric acid involves the use of a cyclone for purification of impurities from the furnace gas generated during the burning of pyrite. The gas, in which there are particles of cinder (mixed iron oxide), enters the cyclone through a special tangential nozzle, then rotates along the inner walls of the apparatus. The accumulation and deposition of dust is carried out in a dust hopper, and the purified gas rises, goes into the next apparatus through a central pipe.
Chemical technology is associated with the use of cyclone in cases where high demands are not made on the resulting gaseous substance.
Wet cleaners
The wet method in modern production is considered one of the most productive and simple types of purification of industrial gases from a variety of suspended particles. The processes and apparatuses of chemical technology associated with the wet purification of gases are currently in demand not only in domestic but also in foreign industry. In addition to suspended particles, they are able to capture gaseous and vaporous components that reduce the quality of the products.
There is a division of such devices into packed hollow, foam and bubbler, turbulent and centrifugal types.
The disintegrator consists of a rotor and a stator equipped with special guide vanes. The fluid is supplied to the rotating rotor through nozzles. Due to the gas flow moving between the rings of the stator and rotor, it is crushed into separate drops, as a result of which the contact of the gases with the trapped particles of liquid increases. Thanks to centrifugal forces, the dust is thrown to the walls of the apparatus, then removed from it, and the purified gaseous substances enter the next apparatus or are released into the atmosphere.
Porous filters
Often, chemical technology involves filtering substances through special porous septa. This method involves a high degree of purification from a variety of suspended particles, therefore porous filters are in demand in chemical production.
Their main drawbacks are the need for a systematic replacement of filter components, as well as the large dimensions of the apparatus.
Industrial filters are divided into granular and fabric classes. They are intended for the purification of industrial gaseous substances having a high concentration of the dispersed phase. For the periodic removal of accumulating particles, special regenerating devices are installed in the apparatuses.
Oil refining features
Subtle chemical technologies associated with the purification of oil products from mechanical impurities and high humidity are based on filtration processes.
Among those processes and apparatuses that are currently used in the petrochemical industry, filtering through coalescing baffles and ultrasound are distinguished. With the help of centrifugal separators, coalescence filters, sedimentation systems, a preliminary cleaning stage is carried out.
In order to carry out complex refining of petroleum products, porous polymer compositions are currently used as filter material.
They have proven their effectiveness, strength, reliability, so they are increasingly using common chemical technology.
Electric filters
Chemical processes in the production technology of sulfuric acid suggest the use of this particular device. The cleaning efficiency in them is from 90 to 99.9 percent. Electrofilters are capable of capturing liquid and solid particles of different sizes, devices operate in the temperature range of 400-5000 degrees Celsius.
Due to the insignificant operating costs, these devices have become essential in modern chemical production. Among the main disadvantages characteristic of such equipment, we highlight the significant initial costs for their construction, as well as the need to allocate large space for installation.
From an economic point of view, it is advisable to use them when cleaning significant volumes, otherwise the use of electrostatic precipitators will be a costly undertaking.
Contact device
Chemistry and chemical technology involves the use of a variety of apparatuses and devices. Such an invention as a contact apparatus is intended for catalytic processes. An example is the oxidation reaction of sulfur oxide (4) into sulfur dioxide, which is one of the stages of the technological production of sulfuric acid.
Thanks to the radial-spiral year, gas passes through a layer with a catalyst located on special partitions. Thanks to the contact device, the efficiency of catalytic oxidations is significantly increased, and the maintenance of the device is simplified.
A special removable basket with a protective catalyst layer allows its replacement without any problems.
Kiln
This apparatus is used in the production of sulfuric acid from iron pyrites. The chemical reaction proceeds at a temperature of 700 ° C. Thanks to the counterflow principle, which assumes the supply of oxygen of air and pyrite in opposite directions, a so-called fluidized bed is formed. The bottom line is that the particles of the mineral are evenly distributed over the volume of oxygen, which guarantees a high-quality oxidation process.
After completion of the oxidation process, the resulting cinder (iron oxide) enters a special hopper, from which it is periodically removed. The resulting furnace gas (sulfur oxide 4) is sent to clean from dust, then dried.
Modern kilns used in chemical production can significantly reduce the loss of reaction products, while simultaneously increasing the quality of the produced furnace gas.
In order to accelerate the oxidation of pyrite in the kiln, in the production of sulfuric acid, the feedstock is pre-crushed.
Shaft furnaces
These reactors include blast furnaces, which form the basis of ferrous metallurgy. The mixture enters the furnace, is in contact with the oxygen supplied through special holes, then the resulting cast iron is cooled.
A variety of modifications of such devices have found their application in the processing of not only iron but also copper ores, and the processing of calcium compounds.
Conclusion
It is difficult to imagine the full-fledged life of a modern person without using a product of chemical production. The chemical industry, in turn, cannot fully work without the use of automated and mechanical technologies, and the use of special equipment. Currently, chemical production is a complex set of equipment and machines that are designed for chemical-physical and chemical processes, automated equipment for packaging and transportation of finished products.
Among the main machines and apparatuses that are in demand in such production, there are those that allow you to increase the working surface of the process, carry out high-quality filtration, complete heat transfer, increase the yield of reaction products, and reduce energy costs.