abstract: this paper describes the components of the discharge system, the common types of faults, the causes and solutions of the failure of the large-scale storage equipment.
key words: large - scale storage equipment, discharge system, fault, cause, method
introduction: large-scale storage equipment with the development of market economy, the state on the implementation of low-carbon environmental protection, energy saving policies and building materials, raw materials, finished product storage and waste disposal of the power industry has a serious waste of land resources, environmental pollution can not control the emergence of the malpractice should be born. its production scale from the initial storage capacity of less than 5000t to the current single-storey storage more than 10,000t, not only save a lot of land resources, but also because of the reduction of dust emissions greatly improved the environmental protection, therefore, is the current industry storage equipment choose the preferred.
warehousing equipment, the effect of the system is the successful use of large-scale storage signs, and large-scale storage equipment, discharge methods are gas-assisted gravity discharge. but in use will be due to various factors caused by the material is not smooth or not expected. this article from the large-scale storage equipment, the composition of the system and the impact of factors to do common sense analysis to help the majority of users targeted prevention and improvement.
1 large-scale storage equipment is a single storage capacity of more than 10000t (including 10000t) or more than 18m in diameter (including 18m) storage materials for cement and other bulk material bulk steel warehouse. the discharge system is a critical component of the entire large storage equipment, is the key to achieving large-scale storage functions. the main contents include warehouse guide system, fluidized system, conveying system, bulk system and control system.
the structure and equipment of the discharge system mainly include the structural floor, the guide cone, the decompression chamber (or the mixing chamber); the wind source (air compressor, fixed capacity blower), the air supply pipe and the valve pipe ; fluidized units of the inflatable box and fluidized rods; conveying system and lifting systems, bulk systems and control systems and so on.
2 the main factors affecting the discharge system
1) guide system, including storage floor and guide cone and other components, tilt angle design. should be based on the storage material of the angle of repose, the angle of the selection is generally greater than the material angle of repairs 5 ° ~ 10 °.
2) fluidization system, including the warehouse to determine the choice of cutting point and the choice of fluidized layout, should be based on the production side of the production layout and requirements, from the economy and rationality as the starting point, give the best way to cut.
3) the fineness of materials, moisture content and storage time of the length of the local outdoor air moisture, groundwater also has a certain impact.
4) conveying system, including the complexity of the pipeline, the length of the transmission distance.
5) skill of technical operators and the mastery and understanding of the system, the material variability requires the operator to be flexible and good at summing up and the ability to innovate.
3 discharge system common faults
discharge system is not expected or poor discharge of the main reasons after several years of exploration and summary, the following points:
1) control system failure: mainly including the solenoid valve failure, discharge control box failure and failure of the valve and so on.
2) fan supply air volume instability, wind pressure instability;
3) the supply pipe back to the ash, the pipeline was blocked;
4) the discharge system suddenly a lot of ash or beyond the design standards;
4 causes the failure of the discharge system
1) control system failure, the main reason:
a solenoid valve: the internal component function failure, or coil short circuit or open circuit;
b the switch button or electronic component in the control box fails, or the connection line is disconnected or connected due to vibration.
c control valve failure mainly realized as turning parts off, spool wear serious, threaded parts slip wire, sealing function of the valve core seal function failure.
2) the air supply and wind pressure instability of the fan is mainly due to: in addition to improper selection of fans, there are roots blower their own reasons such as: ① blade wear gap increases, ② transmission belt is not up to the rated speed , ③ seal or air leakage, ④ pipe valve blue leakage. in addition, the voltage is low and the speed is slow, the pipeline is too long lead to the power of the waste generated by resistance.
3) the influence of the structure of the guide;
the main body of the large-scale storage is a certain function of the material, the design of the floor of the tilt angle of the material to meet the requirements of the angle of the material to determine whether the material can be successfully discharged the key; construction quality is consistent with the design requirements (including the floor surface roughness, flatness and other factors).
the material cone in the warehouse also plays a large role in the unloading of the material, and its influencing factors include the angle of the cone, the design of the length of the cone, and the construction quality of the cone.
as a large storage equipment are used floor type, the floor is located in the ground. for areas with high water levels, the effects of waterproof construction and construction quality on the material are also very important factors.
inflatable different ways also affect the discharge of materials, including the two kinds of inflatable box and fluidized bar, inflatable box and material contact surface is large, the wind through the pipeline and then inflated box within the speed and pressure to reduce the flow of materials the effect is reduced; the fluidized rod and the material contact surface is small, the wind speed and the wind pressure of the compressed wind are not reduced, the general will increase, the material fluidization effect. inflatable bar layout of the floor angle is generally small, is a simple fluidization discharge; fluidized bar layout of the floor angle is larger, generally than the material angle of repairs 5-10 degrees, and a cone to do the auxiliary cone, combined with gravity.
4) the characteristics of the material itself;
as the surface area of the powder material is large, it has a good moisture absorption, so the material batches of different positions or different conditions of the air caused by the formation of different air moisture. the proportion will change with time, the external conditions of the change gradually increased; different batches of material particle size is also a big difference.
5) the impact of storage time.
for fly ash and cement and other powder materials, with the storage time, the material appears compaction or compaction phenomenon, if not timely activation also affected the material discharge. in general, the material storage for a half months to be activated once, especially the fly ash, cement materials.
5 solution:
1) personnel involved in the operation requirements:
a secondary school or above, and in the professional work has a wealth of operation, maintenance and maintenance experience;
b familiar with the industry's production process;
c have a certain degree of mechanical equipment and electrical basic knowledge and operational capacity;
d should have the spirit of love and dedication and serious and responsible attitude.
2) uneven material in the warehouse
a control of the warehouse material moisture or feed when trying to choose dry weather; the original material as much as possible to unload the warehouse, while increasing the dry material to neutralize the operation of the warehouse to restore the state.
b material due to self-weight and moisture reasons for compaction, can be used high pressure air (0.6mpa above) for loosening; warehouse bottom plate tilt angle should be completed after the completion of strict inspection review to ensure that meet the design requirements of the drawings; warehouse bottom material as much as possible friction coefficient of small materials, while the construction should control the floor of the flatness and smoothness.
3) determination of mechanical electrical equipment failure
the failure of the mechanical and electrical equipment of the discharge system mainly includes the failure of the air supply equipment, the control system of the electric control system, the control valve of the pipeline, the failure of the fluidizing device and the obstruction of the pipeline.
for the wind equipment measures: to adjust the voltage to solve the problem of insufficient voltage; try to avoid the pipeline bending the pipe to reduce the resistance to check the seal to avoid air leakage phenomenon.
electrical control operating system main measures to check all the control box components and lines, found the problem after the corresponding connection and repair.
fluidization and delivery piping failure: general pneumatic discharge at the end of the pipeline with a special ash valve or ash hole. after the failure, should stop the discharge, open the ash valve or ash hole access to high pressure air, clear the pipeline; serious, removable pipe flange; fluidized device will have to be replaced after the clear library, library, you should determine which area is a root of a problem, find out after the manual valve can be turned off.
pipeline valve failure solution: open the valve, replace the corresponding spool or spring parts or the corresponding electronic components.
4) for a large number of ash and beyond the design flow of the phenomenon, the general is to check the valve opening and the parameters of the wind is changing, make the appropriate adjustments. if the phenomenon of ash, then check the dust collector, the operation of the safety valve and the transmission pipe seal is damaged.
6 conclusion
the discharge effect of the discharge system involves a variety of factors, only to fully understand and master the nature of the material, the characteristics of storage equipment and the principle of the material system to ensure that large-scale storage equipment, the normal work of the system, better to achieve its due value.
7 reference:
1, welded bulk cement steel silo sb / t10743-2012 china standardization press;
2, the design specifications of the cement plant gb / t50295-2008 china planning press published in december 2008;
3, li cheng powder silo under the reasons for poor and the solution of chemical equipment and pipelines in 2002 the third period
4, fan operation failure analysis
(editor in chief: wang chaohan)
article source: http://www.ccement.com/
