Description
Coal powder and slime dryer
Key words: pulverized coal dryer, slime dryer, pulverized coal production line, pulverized coal drying technology, slime drying equipment
Classification: slime engineering industry
Case overview: it is imminent to dry and reuse the slime. The slime dryer designed by our company adopts the new technology of crushing and dispersing the slime first and then drying it by thermal power, so that the treatment of slime can be realized continuously, industrially and automatically. The drying efficiency is very high, which brings new vitality to the slime drying industry.
Online consultation
Prospect of comprehensive utilization of slime and pulverized coal
At present, the global financial crisis and the collapse of energy have led us to vigorously advocate energy conservation and emission reduction. There are slogans encouraging energy conservation and emission reduction everywhere in the street. Whether it is the home appliances encouraged and supported by the government, or the car going to the countryside, we should try our best to make people feel the benefits, and they are willing to spend money to buy new appliances and cars, which is generally said to stimulate consumption. After all, the storm of the financial crisis hit the whole world, the market has been depressed, small enterprises closed down, people are not willing to spend money and investment if they earn less, the market commodities are not in circulation, leading to the overstock of products of businesses, and the unemployment population is gradually increasing, forming a vicious circle. In order to make us get out of the financial crisis more quickly, choosing a good investment direction is the first problem we are facing. The rapid development of coal mining mechanization has created a rich space for us. The remaining slime after coal washing is a kind of accessory product with great economic value. With the improvement of coal mining mechanization, the proportion of pulverized coal and fine coal in raw coal is increasing, which makes the amount of primary slime in power coal washing plant and flotation tail coal in coking coal washing plant greatly increased. As a by-product produced in the process of coal preparation, coal slime has the characteristics of fine particle size, strong water holding capacity, high ash content and more clay, which brings a lot of inconvenience to the comprehensive utilization of coal slime. At present, the vast majority of coal slime in the washing plant is sold to local farmers at a low price, which not only pollutes the environment but also causes the waste of resources. The economic value of coal slime has not been fully exploited. In the face of increasingly depleted coal resources and high coal prices, it is urgent to dry and reuse the slime. Investment in slime drying equipment, turning waste into treasure, energy conservation and emission reduction, is not only supported by national policies, but also has a high profit return, which is your contribution to Fulu.
Technology of slime dryer and pulverized coal dryer
In the past, centrifugal mechanical dehydration was generally used. The equipment was expensive, the production capacity was low, and the dehydration range was small. Generally, only about 10% of the precipitation could be achieved at one time. The remaining water content is 15-20%. The new technology of slime drying treatment is to solve the problem that coal slime cannot be comprehensively utilized due to its high moisture content (20% - 30%). The new technology of crushing and dispersing coal slime first and then drying by thermal power is adopted, which makes the treatment of coal slime continuous, industrialized and automatic. The moisture content of coal slime can be reduced from 25% to 28% to 12% after drying. Due to the introduction of pre crushing, dispersion, dispersion and anti sticking processes in the coal slime drying process, the drying efficiency of coal slime has been greatly improved, which also brings new vitality to the slime drying industry.
There are many sheets in the cylinder, arranged in spiral shape, which are driven by the rotation of the cylinder body to continuously throw and scatter the materials, and the hitting device on the wall of the cylinder breaks the materials again. The lifted materials fully contact with the hot air flow from the induced draft system, carries out heat exchange, evaporates water, completes drying, and is discharged from the material outlet.
Characteristics of slime dryer
1. The dryer has strong overload resistance, large processing capacity, low fuel consumption and low drying cost;
2. Adopting the forward flow drying mode, the flue gas and the wet material enter the dryer from the same side, so the high-temperature flue gas can be used to obtain high evaporation intensity. The outlet temperature of the dryer is low and the thermal efficiency is high;
3. The operation parameters can be changed according to the different material properties, so that the material can form a stable and completely broken fabric curtain in the dryer cylinder, and the mass and heat exchange is more sufficient;
4. The new feeding and discharging device has eliminated the blocking, discontinuity, unevenness and return of feeding materials of the dryer in the past, and reduced the load of the dust removal system;
5. The new internal structure strengthens the cleaning and heat conduction of dispersed materials, eliminates the sticking phenomenon on the inner wall of the cylinder, and is more adaptable to the moisture and viscosity of materials;
Key words: pulverized coal dryer, slime dryer, pulverized coal production line, pulverized coal drying technology, slime drying equipment
Classification: slime engineering industry
Case overview: it is imminent to dry and reuse the slime. The slime dryer designed by our company adopts the new technology of crushing and dispersing the slime first and then drying it by thermal power, so that the treatment of slime can be realized continuously, industrially and automatically. The drying efficiency is very high, which brings new vitality to the slime drying industry.
Online consultation
Prospect of comprehensive utilization of slime and pulverized coal
At present, the global financial crisis and the collapse of energy have led us to vigorously advocate energy conservation and emission reduction. There are slogans encouraging energy conservation and emission reduction everywhere in the street. Whether it is the home appliances encouraged and supported by the government, or the car going to the countryside, we should try our best to make people feel the benefits, and they are willing to spend money to buy new appliances and cars, which is generally said to stimulate consumption. After all, the storm of the financial crisis hit the whole world, the market has been depressed, small enterprises closed down, people are not willing to spend money and investment if they earn less, the market commodities are not in circulation, leading to the overstock of products of businesses, and the unemployment population is gradually increasing, forming a vicious circle. In order to make us get out of the financial crisis more quickly, choosing a good investment direction is the first problem we are facing. The rapid development of coal mining mechanization has created a rich space for us. The remaining slime after coal washing is a kind of accessory product with great economic value. With the improvement of coal mining mechanization, the proportion of pulverized coal and fine coal in raw coal is increasing, which makes the amount of primary slime in power coal washing plant and flotation tail coal in coking coal washing plant greatly increased. As a by-product produced in the process of coal preparation, coal slime has the characteristics of fine particle size, strong water holding capacity, high ash content and more clay, which brings a lot of inconvenience to the comprehensive utilization of coal slime. At present, the vast majority of coal slime in the washing plant is sold to local farmers at a low price, which not only pollutes the environment but also causes the waste of resources. The economic value of coal slime has not been fully exploited. In the face of increasingly depleted coal resources and high coal prices, it is urgent to dry and reuse the slime. Investment in slime drying equipment, turning waste into treasure, energy conservation and emission reduction, is not only supported by national policies, but also has a high profit return, which is your contribution to Fulu.
Technology of slime dryer and pulverized coal dryer
In the past, centrifugal mechanical dehydration was generally used. The equipment was expensive, the production capacity was low, and the dehydration range was small. Generally, only about 10% of the precipitation could be achieved at one time. The remaining water content is 15-20%. The new technology of slime drying treatment is to solve the problem that coal slime cannot be comprehensively utilized due to its high moisture content (20% - 30%). The new technology of crushing and dispersing coal slime first and then drying by thermal power is adopted, which makes the treatment of coal slime continuous, industrialized and automatic. The moisture content of coal slime can be reduced from 25% to 28% to 12% after drying. Due to the introduction of pre crushing, dispersion, dispersion and anti sticking processes in the coal slime drying process, the drying efficiency of coal slime has been greatly improved, which also brings new vitality to the slime drying industry.
There are many sheets in the cylinder, arranged in spiral shape, which are driven by the rotation of the cylinder body to continuously throw and scatter the materials, and the hitting device on the wall of the cylinder breaks the materials again. The lifted materials fully contact with the hot air flow from the induced draft system, carries out heat exchange, evaporates water, completes drying, and is discharged from the material outlet.
Characteristics of slime dryer
1. The dryer has strong overload resistance, large processing capacity, low fuel consumption and low drying cost;
2. Adopting the forward flow drying mode, the flue gas and the wet material enter the dryer from the same side, so the high-temperature flue gas can be used to obtain high evaporation intensity. The outlet temperature of the dryer is low and the thermal efficiency is high;
3. The operation parameters can be changed according to the different material properties, so that the material can form a stable and completely broken fabric curtain in the dryer cylinder, and the mass and heat exchange is more sufficient;
4. The new feeding and discharging device has eliminated the blocking, discontinuity, unevenness and return of feeding materials of the dryer in the past, and reduced the load of the dust removal system;
5. The new internal structure strengthens the cleaning and heat conduction of dispersed materials, eliminates the sticking phenomenon on the inner wall of the cylinder, and is more adaptable to the moisture and viscosity of materials;
6. The dryer realizes "zero horizontal thrust", greatly reduces the wear of the supporting wheel, and the cylinder runs stably and reliably;
7. The dryer adopts the "self-aligning supporting roller device", which makes the matching of supporting wheel and rolling ring present linear contact, thus greatly reducing wear and power loss;
8. The product granularity and moisture can be controlled according to the user's requirements. When the coal slime is dried, the moisture content of the product can be less than 8%, and the particle size can be controlled below 8mm.
Working process of slime dryer
The drying process of slime is as follows: due to its viscosity, the wet slime is divided into the following working areas after entering the dryer during the drying process: the first is the material guiding area, where the wet slime contacts with high-temperature hot air to quickly evaporate water, and the material is led into the next working area if it fails to form a bond under the action of a large guiding angle sheet; The second is the cleaning area, in which the wet coal slime is picked up by the board to form a material curtain state. When the materials fall down, it is easy to form the phenomenon of sticking drum wall. In this area, due to the cleaning device designed for the equipment, the cleaning device can reasonably clean the materials adhered to the inner wall. In this process, the cleaning device is suitable for the materials Pellet agglomeration also plays a role in crushing, thus increasing the heat exchange area and increasing the drying rate; third, in the inclined lifting plate area, the wet coal slime has been in a low moisture loose state, and the material has no bonding phenomenon in this area. After heat exchange, the material reaches the required moisture state, and enters the ^ ^ The fourth is the discharge area, in which the drum is not provided with a copy board, and the materials roll and slide to the discharge port to complete the whole drying process.
Selection of dust collector for slime dryer
For the unified dust collection of slime drying and pulverized coal drying, it is generally equipped with cyclone dust collector, bag filter, etc.
Cyclone dust collector is also called centrifugal force separator. It uses the centrifugal force generated by the rotating movement of the airflow containing fine powder to separate the fine powder from the gas. It is widely used in convection drying system and is the main equipment to collect products from gas. As long as the design is reasonable and the manufacture is appropriate, high separation efficiency can be obtained. It is possible to capture and collect the large particles in the wet gas discharged from the induced draft system. However, when the particles in the gas are very fine, the effect of cyclone dust removal is not good due to its light specific gravity.
Bag filter (bag filter or bag filter) is often used as the next stage gas-solid separation equipment for separating powder products from dry tail gas, and it is the back line of defense to intercept the powder in tail gas. Bag filter is characterized by high efficiency. It can be said that in many gas-solid separation equipment, its capture efficiency is better than other equipment, especially when it is used to capture particles less than 20 μ m, and the efficiency is more than 99%. The coal slime dryer is equipped with bag filter, which can recycle the fine powder and fine powder not captured by cyclone dust collector, so as to prevent the waste of resources and environmental pollution caused by dust discharged into the atmosphere.
The dehydration and drying of coal slime with high moisture content is used as fuel coal, turning waste into treasure, energy saving and emission reduction. It has the support of national policies and high profit returns, which is your contribution to the prosperity of the road. According to the characteristics of slime, such as fine particle size, strong water holding capacity, high ash content and more clay, a special coal slime dryer was developed. The equipment has advanced technology, compact structure, fast water evaporation, high output, small occupation area, stable and reliable operation, convenient installation and testing. The treated slime can be directly supplied to the coal yard of power plant or blended raw coal for sale.
Cyclone single drum dust collector
The cyclone separator is simple in structure and convenient in manufacture. High separation efficiency can be obtained as long as the design is reasonable and the manufacture is appropriate. Gas with high dust content can also be directly separated, and the pressure loss is relatively small, there is no moving parts, so it is durable. In addition to abrasive materials on the inner wall of cyclone separator wear or fine powder adhesion, there are no other shortcomings. Under normal conditions, the cyclone separator can capture more than 5 μ m powder, and the separation efficiency can reach more than 90%. However, in the actual production and operation, the separation efficiency of rotary kiln is often reduced due to poor manufacturing, improper installation and operation management. Generally, it is only 50% - 80%, sometimes even lower. Cyclone separator is also known as centrifugal separator, slime dryer, it is the use of fine powder air flow for rotary movement of centrifugal force, the fine powder separated from the gas. Strictly speaking, the movement of air flow in cyclone separator is quite complicated. Because of the agglomeration and dispersion of the fine powder, the rebound effect of the wall on the fine powder and the friction between the particles, the separation mechanism is very complex, and the theoretical research has never stopped. After entering the cyclone separator, the airflow with fine powder rotates along the inner wall and descends on the other side. Due to the decrease of the rotation radius after reaching the conical part, according to the law of conservation of momentum, the rotating speed increases gradually, and the particles in the gas flow are subjected to greater centrifugal force. Because the separation velocity produced by centrifugal force is hundreds or even thousands of times higher than that by gravity, the fine powder is separated from the rotating gas flow and separated by falling along the wall of the cyclone separator. When the air flow reaches the lower end of the cone, it begins to reverse, and gradually rotates and rises in the central part, and then it is discharged from the riser.
The smaller the diameter of cyclone, the larger the inlet velocity and the more rotation times, the smaller the separation particle size. For the actual cyclone separator, the critical particle size of the separator is not so accurate due to the disturbance of airflow and wall friction, uneven distribution of particles, rebound effect of particles and wall surface, and the influence of shape. Some fine particles will be mixed into the separated materials in the slime dryer. The pressure drop of cyclone separator is also an important performance index, which is generally proportional to the square of gas inlet velocity.
The separation efficiency of cyclone separator is a very important technical index. The particles in the gas containing fine powder are usually composed of particles with uneven size. In the separation technology, dispersion is often used to reflect the particle size distribution. Dispersion is the mass percentage of various particle size in fine powder. It has been proved that the separation efficiency is not only related to the structure and operating conditions of the separator, but also varies with the particle size distribution. Under the same operating conditions, the total efficiency of the same equipment is also different due to different particle size distribution. Therefore, in the separation technology, the particle size distribution is used to determine the separation efficiency of the separator, which is the classification efficiency. It shows the separation efficiency of the separator for a certain particle size powder. When the treatment capacity is large, the size of one cyclone separator is too large, and the efficiency tends to decline. Several small diameter cyclone separators can be used in parallel to form a cyclone group. Reducing the diameter of the cyclone separator will increase the centrifugal force and the settling velocity of the particles, thus improving the dust removal efficiency.
As an important coal dust removal system in slime drying equipment, bag filter is more efficient and stable in the operation of the equipment. However, as a high-end product structure, it is bound to encounter a variety of problems in the operation. Today, Hongtong drying will give you a detailed explanation of several common problems and solutions.
Dust blocking in ash hopper: as the bag filter adopts water flushing ash discharge, that is, the ash falling into the ash hopper is discharged into the ash flushing water tank through the electric air lock and then discharged by the trench. In winter, the ash hopper is blocked when the boiler is just put into operation or shut down for a long time. The analysis shows that this is caused by the condensation of ash hopper and the loose sealing of electric air lock. The outdoor temperature is low in winter. After the dust collector is started, the hot flue gas will condense in the cold ash hopper wall, which belongs to the stagnant area of flue gas The rapid heating of flue gas makes the ash falling into the ash hopper stick to the wall of the ash hopper, resulting in ash blockage; at the same time, if the electric air lock is not tightly closed, the "water vapor" in the ash flushing water tank will be sucked into the ash hopper, which will agglomerate at the lower ash mouth of the ash hopper and cause ash blockage easily. In addition, the low power of the ash hopper heating device and the unfair installation position are also the causes of ash blockage. Therefore, in the design of the ash hopper, the power and installation position of the ash hopper heating device should be calculated on the basis of fully considering the local air temperature and ash discharging form, and the ash hopper preheating program should be added in the bag starting control; at the same time, the safe and reliable air lock with good sealing performance should be selected, and the heat preservation of the ash hopper should be strengthened.
2. Faults of back blowing and cleaning system: the main causes are: no action of back blowing solenoid valve, water accumulation in compressed air pipeline and jamming of rotary mechanism. The quality problem of back blowing electromagnetic pulse valve is the main reason for its non action; in addition, the quality of back blowing compressed air (mainly containing water and dust) and the stability of power supply will affect the normal operation of the solenoid valve. In winter, the outdoor temperature in the north is lower, so the compressed air pipeline arranged outdoors is easy to accumulate water or freeze. Therefore, when designing the outdoor compressed air pipeline, the water discharge point and thermal insulation measures should be designed, and heat tracing should be added in especially cold areas. As one part of the rotary mechanism operates in the high temperature flue gas, the other part operates under the ambient temperature. The temperature difference between the two parts is large, which easily causes deformation and jamming. Therefore, the temperature factor should be fully considered in the design.
3. Control mode of back blowing: the frequency and strength of back blowing and cleaning is one of the main factors affecting the service life of bag filter. Due to the large fluctuation of boiler load and coal quality in power plant, the flue gas volume and dust concentration of flue gas have great fluctuation. Therefore, in the design of control mode of back blowing, several back blowing modes should be set as much as possible according to the pressure difference between the upper and lower chambers of the precipitator (air purification chamber and bag chamber), so as to adapt to the change of coal-fired boiler working conditions and prolong the service life of dust remover.
