What are the basic parameters that the roller press can adjust?

Product introduction:https://www.lvssn.com/mill/Roller-Press.html

Jiangsu LVSSN company core cement epc

The roll press is like the roll crusher, but its function is different, there are essential differences.Roller mill in cement powder has occupied a dominant position, what are the basic parameters of roller mill can be adjusted?
 

1. Working principle of roller press

 

The roller press consists of two rollers (namely moving roller and fixed roller), frame, reducer, torque support, motor, pressure system and feeding device.When the two rollers run in opposite directions under the power, the material from the upper part is pulled into the gap between the two rollers. Then the hydraulic cylinder installed on the back side of the moving roller starts to pressurize, driving the piston forward and pushing the moving roller to put pressure on the material.With the two rollers continue to pull the material into the gap of the roller and compacted and crushed, into the cake unloading, the cake after the finished products into the mill or storage, unqualified products return to continue rolling, until the final complete grinding.
 

2. Parameters of roller press

 

2.1 pressure of roller press

The pressure of the roller press is a key parameter of work efficiency.The yield of ground powder is almost determined by pressure.When the pressure is 60MPa, the passing rate of 32 micron fine powder is about 20%. If the content of fine powder increases to 30%, the pressure should reach 100-300mpa.At the same time, the experiment shows that when the pressure is very high, the increase of fine powder production rate is not obvious, but the power consumption is doubled. At the same time, because of the pressure increase, the material cake is not easy to break, the power consumption of tube mill will also increase.The conclusion of the experiment on a small roller press is that when the passage rate of 45 microns is 36.1%, the required working pressure is 205MPa, from which it can be seen that the passage rate of 80 microns will be higher.Domestic data show that the average roll pressure in 120- 150MPa, 0.08 fine powder production rate can reach 50%.

Combined with the actual situation, the average roller pressure should be more than 60MPa, if it can reach more than 100MPa is the best, so not only the fine powder production rate is high, high work efficiency of the roller press, but also reduce the cycle load, transmission equipment energy consumption will be reduced, is conducive to reducing the system power consumption.
 

2.2 control of feed size

The feed particle size of the roller press, can be determined by 3.5% of the roller diameter, under the appropriate pressure, stable operation, should not be too large, the data shows that when the diameter of 7.0% of the roller diameter, the current fluctuation of the roller press will increase several times, not conducive to stable operation.
 

2.3 selection of roller seam

Roller gap is also one of the important parameters of roller press, generally 2.0% of roller diameter.The original roller gap is generally about 10mm. It needs to be reminded that, before setting the original roller gap, the radial runout of the roller should be tested radial, the most prominent position of the two rollers should be transferred to the horizontal position of the opposite direction, and then the limit block should be fixed so that the gap is about 10mm, and the two axes should be parallel.

 

2.4 installed power of roller press

When the average roll pressure is at 60MPa, the power consumption of tons of materials is 2.4kw, but the actual pressure at ordinary times will be about 1.5 standby. A large number of experimental data show that rolling a ton of clinker requires 3.5kwh, a ton of limestone requires 3.0kwh, and a ton of slag requires 6.0kwh, so the installed power should be greater than this value.
 

2.5 selection of roll seam displacement

Roller press roll gap to stabilize the best, but in actual operation, due to the change of particle size, the influence of oil compressibility, vibration, etc, is bound to change, but I did not allow unlimited expansion, roll gap must set a reasonable displacement, if the displacement is too large, will surpass the self-aligning bearing Angle, bearing damage, so must limit, generally offset control in 3 to 5 mm, but the best through the allowed Angle calculated bearing, both to ensure the safety of bearing, also ensure the extrusion effect.
 

2.6 roller linear speed

The linear velocity of roller is closely related to the production, but the experiment shows that the linear velocity is linearly related to the production when the linear velocity is 0.2-1.5 m/s.When the linear velocity is 1.5-1.8m /s, the relationship between output and velocity decreases, indicating that the ability of roller to bite the material is decreasing.Therefore, the linear speed of the roller press should be below 1.8m/s.
 

2.7 output of roller press

The output of the roller press is measured by the passing quantity, which is related to the speed of the roller, the volume and weight of the cake, the thickness of the cake and the width of the roller.namely

G = 3600 BVSP (t/h)

Where: t/h for table G, width meter for B roller, linear velocity meter/S for V roller, thickness meter for S cake, about 2.25% of the straight diameter of the roller., the bulk weight of p cake is about 2.4 tons/m3.

In fact, after the installation and use of the roller press, the structure parameters can not be changed, only the size of the pressure, the size of the roller gap offset, the size of the size of the material size and the number of recycling materials.Pressure is the most critical data, which directly affects the work efficiency, fine powder production rate;The difference of roller gap not only affects the bearing installation, but also affects the roller pressure effect.Granularity involves operational stability;The amount of circulation also involves the density of incoming materials, too much fine powder or granular material too much will cause the entry of excess air, not conducive to stability and so on.

The page source:https://www.lvssn.com/Product/What-are-the-basic-parameters-that-the-roller-press-can-adjust.html

The reasons and solutions of grate gap clogging in grate cooler

Product introduction:https://www.cementepc.net/burning/Grate-cooler.html

Jiangsu LVSSN company core cement epc

Grate cooler is an important equipment in the rotary kiln system. On the one hand, it cools the hot clinker out of the kiln to a suitable temperature. During the cooling process, it displaces the heat energy in the clinker and contains it in the hot air.On the other hand, through the grate bed advance, the clinker will be transported to the appropriate location, broken into storage.Therefore, the role of grate cooler can be for cooling clinker, convenient transportation, convenient storage;Replacement of heat energy, effective saving of coal.

Grate for grate cooler is very critical, is the passage of the wind, the size of its section area is related to the wind resistance and through the amount, but this has been determined in the design and manufacturing, the use of units is to find a way to maintain this parameter, prevent the grate plug.The reasons and solutions of grate gap clogging in grate cooler

1. Reasons for grate blockage

 

1.1 improper material cushion of pu before kiln opening

For example, the cushion powder has more particles and less, the cushion clinker is moist, small particles and powder will be trapped in the grate, at this time the fan of the grate cooler cannot be opened, but the temperature rises with the temperature of the kiln, clinker condensation will occur, so when the fan is opened, in fact, part of the grate has been blocked.
 

1.2 wet bottom of grate bed

Some enterprises in order to reduce the temperature of the residual air, often in the grate cooler to add atomized water, once the wind temperature low atomized water, will cause wet bottom, sometimes even stop the water, the result of the grate is firmly paste.
 

1.3 the clinker with liquid phase enters the grate cooler

For example, due to improper ingredients, adjustment on the kiln did not follow up, viscous belt liquid clinker into the grate cooler, if the adjustment is improper at this time, not only cause a snowman, but also cause grate plug.In addition, improper operation of the burner causes pulverized coal to fall into the grate cooler for combustion, and the clinker becomes sticky and blocks the grate cooler.
 

1.4 improper operation

Mainly refers to the operation does not adapt to or do not follow the grate bed of the wind change, such as the material layer changed, the wind pressure did not increase, sometimes even shut down the press;For example, improper shutdown, improper shutdown sequence, belt material stop wind, and so on, easy to cause plug grate.

2. Solution to plug the grate

 

2.1 block prevention before starting up

Before starting up the system, it is generally necessary to lay the clinker cushion at the hot end of the grate bed to prevent the burning of the hot clinker and the damage of the grate plate by the impact of large clinker.In the early stage of kiln ignition, the grate bed does not operate and the fan does not open. If the clinker cushion is moist and pink, it is easy to plug the grate seam of the grate cooler. Therefore, the clinker cushion should choose dry granular clinker.
 

2.2 during maintenance, the grate shall be cleaned carefully

During maintenance must be based on the usual situation, to the grate carefully cleaned, one by one inspection, cleaning, if not clear, must be replaced, otherwise inevitably affect the cooling effect.
 

2.3 strictly control atomized water

If some enterprises set atomized water on the top of the grate bed of the grate cooler, the atomized water amount and atomization effect should be strictly controlled to ensure that atomized water droplets vaporize before falling on the clinker. Meanwhile, the operation must match with the system, otherwise the wet bottom may occur at any time, and water should be stopped before the shutdown.
 

2.4 timely adjustment and reasonable operation

No matter from the aspect of technology, or from the aspect of equipment, reasonable operation and timely adjustment are needed. However, there are too many contents involved, and only a few items can be highlighted. For example, if there are multiple layers of incoming materials, the grate speed should be accelerated, and the wind pressure and air volume should be adjusted.The material layer is thin to drop the grate speed, reduce the air volume and stop the machine.If the fan fails, it should be opened in time. If the shutdown time is long, it must stop the grate cooler or other corresponding measures.Otherwise it is easy to plug the grate.And so on.

For the cold machine, the grate is very important, if you encounter other reasons for congestion or have a better solution can leave a message with us.

The page source:https://www.cementepc.net/company/The-reasons-and-solutions-of-grate-gap-clogging-in-grate-cooler.html

A new method of wind lock for vertical mill feed

Product introduction:https://www.lvssn.com/mill/Raw-material-vertical-mill.html

The vertical mill, as a windswept mill, must work under the condition of negative pressure.The system air leakage must be reduced as much as possible to realize the function of air lock while ensuring the normal feeding amount of the vertical mill.A new method of wind lock for vertical mill feed
 

 

As shown in the photo, the wind lock function is completed by the variable diameter screw conveyor, that is, in the process of conveying incoming materials, the screw conveyor compacts the materials and fills the housing by changing the diameter to realize the wind lock.
 

1. The principle of wind lock is

The incoming material will be sent to the diameter change through the front spiral blade to become densified and fill the shell into the storage area, forming a tight seal area. Through the continuous push of the screw and extrusion of the material, the material will continuously enter the discharge pipe of the vertical mill center.

 

This type of air lock has obvious advantages over other types of seal.Because the design capacity of rotary feeder is far greater than the capacity of the vertical mill, more cold air is fed into the feed at the same time, and the surrounding clearance will also enter a lot of cold air under the high negative pressure of the vertical mill, the main reason is that the shape is not reliable seal.Compared with the current improved feeding air lock system of silo + positive displacement feeder + weighing scale, this new type of air lock has the characteristics of simple equipment, easy arrangement and few fault points.
 

2. Advantages of screw conveyor for vertical mill feeding

 

Screw feeding has obvious advantages.

Theoretically speaking, it can be considered that the material seal completely isolates the contact between the mill and the outside world and can completely block the cold air from entering the mill.

 

(1) variable screw conveying can pass the gradual compaction and hoarding of materials, which can eliminate the leakage of materials into the vertical mill.

(2) compared with more precise volumetric feeding, the failure rate and clogging probability are reduced, and the maintenance is relatively simple.Variable screw conveyor, one machine more, convenient layout, simple transformation.

(3) compared with the bin + volume feeder + scale, the failure rate is low, the investment is small and the control is simple.

(4) compared with other forms of feeder, central feeding can be realized and local impact wear of feeding tube in the opposite grinding center can be avoided.

(5) good air lock is achieved, which effectively improves the utilization rate of hot air, reduces the load of the system dust collector, and provides favorable conditions for extending the life of the filter bag and realizing ultra-low discharge.

(6) even if the vertical mill is shut down, there is always material seal at the end of the conveyor, which still plays a good sealing role.

This new method can meet the requirement of water content less than 20%.The machine head and tail are equipped with external support devices and grease pipelines, which can be directly transferred to the grease lubrication station during the transformation to ensure the bearing life.At the same time, the blade has high - quality wear - resistant material, greatly increased the use cycle of the product.

The page source:https://www.lvssn.com/company/A-new-method-of-wind-lock-for-vertical-mill-feed.html

Rotary kiln with refractory materials most afraid of what?

Product introduction:https://www.lvssn.com/bruning/Rotary-kiln.html

One of the main features of the rotary kiln is that the refractory materials masonry in the kiln rotate with the shell at high temperature.Refractory bricks not only have to be subjected to thermal shock, erosion and wear of kiln gas and materials, but also have to bear the pressure of squeezing each other and the shell during vibration and rotation.Rotary kiln with refractory materials most afraid of what?
 

1. For refractory materials used in rotary kiln, the most feared is the frequent stopping and opening of kiln.

The service life of rotary kiln is directly affected by the number of kilns stopping.In the production of rotary kiln, the frequent opening and stopping of kiln will cause the hot surface of firebrick to cool down quickly and shrink too fast. The structure inside firebrick will be seriously damaged.When the kiln is opened again, the hot surface layer of refractory brick often falls off with the kiln skin, which also distorts the brick position inside the kiln lining and reduces the service life of the kiln lining.

 

2. Control the opening and stopping times of rotary kiln

Firstly, the stable operation of rotary kiln equipment should be ensured. Secondly, the stable quality of all fuels should be ensured. Meanwhile, the stable quantity of coal and materials should be controlled.
 

Each kiln opening time should be carefully considered and deployed for the best:

1. 2 hours before the rotary kiln is scheduled to turn off, the decomposition furnace shall gradually reduce fuel, and then gradually reduce raw material, so that the temperature of the preheater system cannot be super high.

2. Open the cold air valve slowly so that the inlet temperature of the high-temperature fan does not exceed 400℃.

3. When the temperature at the outlet of the decomposition furnace drops to 600 ~ 650℃, the material is completely stopped and the kiln speed is reduced to 0.5r/min to control the fuel

4, reduce high temperature fan draft.

 

5, with the reduction of wind, reduce the rotary kiln kiln head feeding fuel, do not make the raw material out of the kiln.

6. Stop spraying water on the humidifier, and then continue to reduce wind.

7. When the tail temperature drops below 800℃, stop the kiln head to feed fuel, then stop the high-temperature fan, open the cold air valve, and control the air volume with the inlet valve of the kiln tail exhaust fan.Note that after the fuel is stopped at the kiln head, maintain the necessary primary air volume to prevent deformation of the coal injection pipe.

8. Stop the cylinder cooling air unit and kiln mouth sealing ring cooling fan according to the situation.

9. Stop the big cloth bag at the end of the kiln, return to the conveying system and the raw material feeding system.

10. When the temperature of rotary kiln barrel reaches below 250℃, the auxiliary transfer kiln shall be changed.

11. After the kiln head is turned off, pay attention to the negative pressure control of the kiln head, reduce the gas flow of the grate cooler and let the kiln head exhaust fan exhaust the air.

12, in the kiln discharge is not much, the grate cooler stopped for a period of time, from six to one room each fan stop.

13. Stop kiln head electric dust collector, clinker conveying, primary fan, kiln head electric dust collector exhaust fan, control kiln negative pressure with kiln tail dust collector and exhaust fan.

14. Stop feeding the raw material fan according to the situation and gradually pull out the coal jet pipe.

The above ten strict control words, will be able to reduce the number of kilns, kilns, so that the rotary kiln refractory brick service life increased.

The page source:https://www.lvssn.com/Product/Rotary-kiln-with-refractory-materials-most-afraid-of-what.html

Characteristics of cooperative disposal of solid waste by cement kilns

Product introduction:https://www.cementepc.net/burning/Cement-rotary-kiln.html

Cement kiln collaborative disposal of solid waste is also the use of high temperature treatment of waste.But different from waste incineration, the collaborative disposal of cement kiln directly utilizes the high temperature of cement production line kiln, and the temperature is much higher than that of waste incineration plant.Characteristics of cooperative disposal of solid waste by cement kilns.
 

(1) high incineration temperature.

The temperature of materials in cement kilns is generally higher than 1450℃, and the temperature of gas is higher than 1750℃ or so, even higher than 1500℃ and 2200℃.Under this high temperature, the organic matter in waste will produce thorough decomposition, general incineration removal rate of 99.99% above, for the waste of toxic and harmful components will be thoroughly "destroyed" and "detoxification".

(2) long stay.

Cement rotary kiln tube body long, waste in the cement kiln high temperature state for a long time.According to the general

According to the statistical data, the total residence time of materials from kiln head to kiln tail is about 4omin.The residence time of the gas above 950℃ is more than 8s, and the residence time above 1300℃ is more than 38, which can make the waste under high temperature for a long time

Good for waste combustion and thorough decomposition.
 

(3) stable burning state.

The rotary kiln of cement industry has a very stable combustion system with high thermal inertia.It is composed of rotating dense metal cylinder, brick masonry in kiln, crust formed in the firing zone and materials to be fired. It not only has a huge mass, but also increases the thermal inertia of the system due to the thermal insulation performance of refractory materials, and will not cause large temperature fluctuation due to the change of waste input and nature.
 

(4) good turbulence.

The flow direction of high-temperature gas and material in cement kiln is opposite, and the turbulence is strong, which is conducive to the mixing, heat transfer, mass transfer, decomposition, combination and diffusion of gas-solid phase

(5) alkaline environmental atmosphere.

The raw material composition used in the production of cement determines that there is an alkaline atmosphere inside the rotating density. The alkaline material inside the cement density can be neutralized with the acidic material in the waste as stable salts, which can effectively inhibit the discharge of acidic material and facilitate the purification of its tail gas. Moreover, it can be carried out together with the cement process.
 

(6) no waste residue is discharged.

In the process of cement production, there are only raw materials and clinker produced by calcining process, and there is no problem of slag produced by incineration in general incinerator
 

(7) solidify heavy metal ions.

The most heavy metal ions in the waste can be solidified in the clinker and finally into the cement product, avoiding the re-diffusion
 

(8) reduce overall emissions.

The substitution of combustible wastes for mineral fuels reduces the demand of the cement industry for mineral fuels (coal, natural gas, heavy oil, etc.).Overall, the emission of waste gas (CO2, SO2, CI, etc.) from cement production and incineration alone is greatly reduced.

(9) chu burning disposal points, strong adaptability.

The firing system of different process in cement industry, no matter it is wet kiln, semi-dry kiln, preheating kiln and cyclone preheating kiln with decomposition furnace, the whole system has different high temperature feeding points, which can adapt to different kinds of wastes of different properties and forms.
 

(10) good waste gas treatment effect.

Cement industry firing system and waste gas treatment system make the waste gas after combustion go through a long path and good cooling and dust collecting equipment, and have a high adsorption, sedimentation and dust collecting effect. The collected dust can be reused through the conveying system and returned to the raw material preparation system.
 

(11) the construction investment is small and the operation cost is low.

The use of cement compact-cement for waste disposal, despite the need for necessary modifications in process equipment and feeding facilities, and the need for new waste storage and treatment facilities, has greatly reduced investment compared with the construction of new dedicated incinerators.In terms of operating cost, although the depreciation of equipment, consumption of electricity and raw materials, labor costs and other costs increase, burning combustible waste can save fuel and reduce fuel costs. The higher the proportion of fuel replacement, the more obvious the economic benefits.

The page source:https://www.cementepc.net/productknowledge/Characteristics-of-cooperative-disposal-of-solid-waste-by-cement-kilns.html