coal storage silo
- Solid structure & strong resistance to corrosion
- Short construction term
- Lime silo's service life can reach 30 years
- Diameter: 3-28m
- Maximum height: 28m
The technology of storing coal in silos has been used in some power plants and coal mines. Coal storage silo usually use cement silo or steel silo, at present, there are more application of cement silo. However, cement silo take a long construction period and high investment. Lipp steel silo as the leader of steel silo, has been gradually used in grain and oil, brewing, building materials, environmental protection, chemical industry, energy and other industries, such as YIDONG GROUP, Ningbo Kangli Glass Co.,ltd, etc.
Lipp Silo is well-known by the technology invented by Germans named Mr.Xaver.Lipp. In 1960s and 1970s introduced to China. In 1980s start application in the field of cement building materials, now widely used in cement plant, grinding station, hydropower station, thermal power station, cement transfer depot, etc.
Lipp Silo technical performance and features
- Good integrity and long service life. Lipp Silo in the whole process of construction using the special equipment, greatly strengthened the carrying capacity of the silo body, so the silo has high integral strength, good stability and excellent seismic performance.
- High sealing performance, prevent rain and leakage. Lipp Silo due to it’s five layer undercut technology, so it has high sealing performance, can prevent rain and leakage. Can prevent cement, fly ash and other materials caking and hardening.
- Short construction period, low cost.
- Using field construction, Lipp equipment can provide a shaping speed of 3-5m per minute, So the construction period is short. A coal silo with a high of 15m could be constructed within 8-10 days. Cost-effectiveness can be achieved for light sheets are used for the whole silo which made it just as heavy as the concrete silo.
- Covers small area, easy to manage. Lipp Silo’s height and diameter can be arbitrarily selected within a larger range. comparably small coverage that could narrow the two silo separation distance down to 500mm for maximized space utilization.
The construction technology of Lipp Silo is the world's most advanced steel silo construction technology. It’s construction method is unique: When construction, put The 495mm width of the coil from the decoiling machine into forming machine rolled into the desired geometry then through the bending machine. During the rolling process, the silo wall undercut a 30mm-40mm spiral convex strip, which is 5 times thicker of the material (see Figure 1). Install stiffener in the silo,structurally strengthen the strength of the silo.
Explore the use of Lipp Silo coal storage process
Production flow (take coal silo for example)
A complete set of coal silo system includes feeder system, dedusting system, gas path arch breaking device, the silo body, electrical control system, under carriage, guardrail and other components.
On the top of coal silo, there equipped with an electric dedusting device, which can reduce the amount of pollution on the surrounding environment. When dust accumulate to a certain degree on the top of dust catcher, it’s easy to start the vibration motor to shake them off through electrical control.
There also equipped with a level e sensor on the top of the silo, or equipped with a radio-frequency capacitive material level limit switch both on the top and bottom of the coal silo.
When the switch is on, we can be aware of the body height of materials inside the silo through the electrical signals and then analyze the inventory of coal or other powders.
On the cones of silo bottom, there equipped with an air blowing arch breaker. By using small electromagnetic directional valve in the pneumatic box, it’s available to control the release compressed air, which helps to the broken arch of coal powder and avoid accumulated plugging. The air supply can be provided through gas circuit by supporting stirring device, and the start of air blowing arch breaker can be controlled by electrical system according to the supply time of coal powders. Namely, when the material supply time is beyond the set time, the automatic blowing broken arch can also be controlled manually.
Conveying powder material from feeding tube to coal (fly ash) silo, bulk coal or fly ash can be directly sent to the silo by bulk material vehicles.
Coal silo is provided with a coal silo grounding protection device.
Type of silo layout can be set according to the requirements of the factory. In the selection of steel silo should according to the actual needs and circumstances to choose.
Discharge mode of silo
Due to the poor mobility of coal, the discharge mode of the silo usually use inverted cone. Cone wall angle should be greater than 45 degrees, easy for discharge. Discharge port can be used with double feed port, multiple feed port etc. In order to prevent eccentric unloading, to ensure that the main structure of the silo is balanced and the discharge port should be symmetrically arranged.
Problem of coal arch blocking
Application of large capacity Philips silo in the coal storage and transportation, are more prone to arch blocking phenomenon. There has many existing coal bunker arch breaking method. Commonly used Artificial broken arch method, Hydraulic broken arch method, Wind broken arch method, Vibrator broken arch method, Air guns, etc. Should according to the specific circumstances of Lipp Silo choose one or more methods.
Problem of dust explosion in silo
Coal in the long-term storage of steel silo prone to spontaneous combustion. In the process of spontaneous combustion, it not only releases heat, but also releases combustible gas with different content. When the temperature, the concentration of combustible gas and dust concentration reaches a certain value, the steel silo is very easy to explode, and the measures to prevent explosion should be taken.
- Enter the inert gas in the steel silo, to reduce mixture of dust and combustible gas. Destroy the combustion condition of coal dust and flammable gas, to avoid explosion.
- Build ventilation system, using thermal insulation system to shorten the coal storage cycle.
- Establish GD2000 combustible gas detector matching use with combustible gas alarm controller, composition of Lipp Silo safety inspection system, timely and accurately find abnormal situation. When there is a combustible gas in the silo, the detector can immediately send out the electrical signal which is proportional to the content of the combustible gas in the air. Signal transmitted to the alarm controller can display (or record) the concentration of combustible gas in the air, at the same time sent out sound, light alarm and control signal, so as to ensure the safety of production, to avoid the occurrence of malignant events.
Lipp silo try to choose galvanized plate
Choose galvanized plate can effectively prevent the coal silo wall corrosion. For other parts of the inner wall of the silo, such as stiffener need to brush paint for anti-corrosion and regular inspection.
Problem of coal spontaneous combustion
Due to the special nature of coal, it is very prone to spontaneous combustion, the following measures can be used to prevent.
- Adding insulation layer outside the silo wall. In northern China, the winter is very cold, the insulation layer out of the silo wall can prevent the coal from freezing and agglomeration. Also can prevent steel silo in the southern region because of the high temperature out side the silo caused coal in the silo heating up too fast caused spontaneous combustion of coal. Heat insulating material usually use rock wool attached with color steel plate outside.
- Steel silo has complete ventilation system. To prevent coal spontaneous combustion, must reduce the temperature inside the silo, so the construction of ventilation system is the necessary condition of the silo. At the bottom of the steel silo set the ventilator, through the Ventilating duct leading-in the outside dry cold air to the ventilation geosyncline vent pipe, using the diffusion of gas continuous heat exchange with coal in silo, timely discharge the hot gas in silo to achieve the purpose of reducing the temperature. The roof of Lipp Silo all installation explosion proof vent, AQZZ series steel silo pressure release device, can achieve some ventilation explosion-proof effect.
- Using temperature measuring cable to detect the temperature of coal in silo. When the temperature reaches the set value, the alarm signal is sent out.
- Enter the inert gas in the silo to prevent coal spontaneous combustion or dust explosion.
Economic and technical comparison between Lipp Silo and Concrete Silo
Technical performance comparison with Concrete Silo
Technical performance comparison between Lipp Silo and Concrete Silo are shown in table 1.
|No.||Item||Lipp Silo||Concrete Silo|
|1||Sealing Property||Good air tightness, can store liquid||Good air tightness|
|2||Service Life||More than 20Years||More than 50 Years|
|3||Construction Method||Imported equipment, mechanical operation||Sliding mode construction|
|4||Maintenance Work||Regular maintenance, small amount of maintenance||No need to maintain|
|6||Meteorological requirement||Construction is not affected by the weather||Construction affected by the weather|
|7||Environmental requirements for construction||Less||More|
Economic comparison with Concrete Silo
Mengyuan coal Co.,ltd, used Lipp Silo in their lignite project. The economic comparison with the same type of concrete silo are shown in table 2.
|No.||structural style||Lipp Silo and Concrete||Complete Concrete Silo|
|1||Quantity of coal silo||1||1|
|2||Coal silo specification/m||Φ15×H18||Φ15×H18|
|4||Silo wall thickness/mm||4.0||4.0|
|5||Heat preservation||Rock wool, Choi metal||-|
Conclusion:Lipp Silo compared with Concrete Silo, the former is more economical and practical, it also has the characteristics of beautiful appearance, excellent construction, short construction period and so on. Especially introduce the important problem that coal storage in Lipp Silo should avoid and notice. We are sure that Lipp silo will be widely used in the coal industry with it’s unique advantages, and play a greater role in the energy sector.