CN111520735A

CN111520735A - Step-by-step decrement coal preparation system

Info

Publication number: CN111520735A
Application number: CN202010394723.XA
Authority: CN
Inventors: 马琳
Original assignee: Sichuan Union Heavy Electrical Equipment Manufacturing Co ltd
Current assignee: Sichuan Union Heavy Electrical Equipment Manufacturing Co ltd
Priority date: 2020-05-12
Filing date: 2020-05-12
Publication date: 2020-08-11

Abstract

The invention discloses a step-by-step reduction coal preparation system, wherein a screening machine is arranged on a belt conveyor right below a coal hopper in a coal yard, and qualified particle sizes of screened undersize products enter a boiler bin through an A/B main belt conveyor. The oversize (unqualified particle size) falls to another belt conveyor, enters a crushing plant, is coarsely crushed, finely sieved and finely crushed to reach the qualified particle size, and is converged with an A/B main belt to enter a boiler bin. The invention solves the problem of repeated crushing of materials, reduces the construction cost and the equipment acquisition cost of one crushing building, and can realize the purposes of energy conservation and consumption reduction for a long time. Is a major technical breakthrough in the industry.

Description

Step-by-step decrement coal preparation system

Technical Field

The invention relates to a step-by-step reduction coal preparation system of materials, in particular to a screening process of a circulating fluidized bed boiler coal conveying system. The method is mainly applied to a coal conveying system in the thermal power industry, and can also be applied to the process and particle size control in the industries of coal, chemical industry, coking, mines and the like.

Background

A circulating fluidized bed boiler of a thermal coal gangue power plant burns coal gangue particles with a certain proportion of particle size. In other words, the heat value of the pulverized coal furnace and the particle size of the fluidized bed boiler are used. The circulating fluidized bed boiler is generally a boiler which carries out high-energy-efficiency power generation by burning coal gangue particles within the range of 0-10mm, and in the preparation process of the coal gangue particle size, under the condition that a screening and crushing device at the front end fails, the coal gangue particle size is out of control, and the requirement of the boiler combustion ratio particle size is not met.

As is known, the percentage of acceptable particle size of 0-10mm in a coal yard is generally 40-85%, and usually about 65%.

The requirement of the correct proportioning of the particle size curve of the coal as fired is as follows: 15% of 0-1 mm; 25% of 1-3 mm; 25% of 3-6 mm; 20% of 6-8 mm; the thickness of the film is 10% by 8-10mm and less than 5% by 10-13 mm. However, each boiler plant and boilers with different tonnages have partial slight deviation on the curve proportion of the coal as fired.

Various enterprises belong to large materials, and purchasing procedures are complex. More ore, silt, coal slime, water injection and impurities doped in the coal provide more rigorous requirements on coal blockage, output and discharge particle size of subsequent crushing and screening equipment.

The particle size of coal as fired of various circulating fluidized bed enterprises at present has the dipolar differentiation phenomenon (the thickness proportion is unreasonable) of different proportions, namely: 0-3mm in proportion of 65%; the proportion of 10-30mm is 25%. The main reasons for this phenomenon are poor quality of coal, serious repeated crushing, and unreasonable screening and crushing equipment and process and type selection.

The boiler is affected by the exceeding of the grain size of the coal as fired: the boiler output is insufficient (coal particles are not fully combusted), and the carbon content of fly ash and slag of the boiler is increased (coal is not completely combusted); the abrasion of the water-cooled wall of the boiler is aggravated to cause frequent pipe explosion accidents, and the production is influenced by blowing out the boiler; the energy consumption is increased by the blast volume of the boiler after the particle size exceeds the standard; the slag discharging is not easy to be smooth after the grain diameter of the slag exceeds the standard, the cooling of the slag cooler is difficult after the grain diameter of the slag exceeds the standard, the overhauling and maintenance amount is increased, and the like. The boiler is better than the stomach of human body, and the coal gangue particles burnt in the boiler are better than food, and a series of symptoms such as abdominal pain, dyspepsia, difficult excretion and the like can be caused after the excessive massive bone and abnormal food enter the stomach.

Currently, a small part of newly built users have realized that important technical nodes of a coal making system are as follows: the system has the core problems of high output, equipment type selection, capital investment, equipment purchasing cost, long-term operation energy-saving cost, fired coal particle size ratio, particle size dipolar differentiation and the like, and needs to be solved.

A small percentage of users currently in operation have realized that important technology nodes of a coal production system are: the problems of output, coal blockage, secondary polarization of particle size and over-standard particle size.

In order to solve the problem that coal gangue and sundries are mixed and burned, a three-stage screening and crushing system is additionally arranged in many enterprises. The problem that most of particle sizes exceed standards is solved, but the particle sizes are not perfect enough.

It is known that four types of crushers, i.e., ring hammer type crushers, toothed roller type crushers, reversible crushers, and screening crushers, are generally used in coal manufacturing systems of power plants at present. Each crusher has the advantages and disadvantages, 1, the ring hammer crusher has small output, is not sticky with wet materials (coal materials), is easy to block, has low equipment price and qualified discharged particle size; 2. the gear roll crusher has small output, avoids sticking wet materials (coal materials), is not easy to block, has moderate equipment price and low qualified rate of discharged particle size; 3. the reversible crusher has large output, avoids sticking wet materials (coal materials), is not easy to block, has high equipment price and higher qualified rate of discharged particle size; 4. the screening crusher has large output, is not sticky with wet materials (coal materials), is not easy to block, and has low qualification rate of discharged particle size in equipment price.

Screening machines are widely available in various types, and can be classified into conveying type screening, vibration type screening and guide type screening. The conveying sieving machine includes roller sieve, sine sieve, cross sieve, sieving distributor, etc. The vibration type screening is provided with a vibration screen and a high-amplitude screen, and the guide type screening is provided with a rotary screen, a double-rotary screen, an impeller screen and the like. The conveying type sieving machine has the two advantages of no material blockage, large output, uniform material distribution and medium sieving efficiency; the vibration type sieving machine has the defects of large pile of blocked coal, small output force, large vibration noise, low sieving efficiency and uneven distribution; the guide type screening has the defects of large pile, coal blockage in output, low screening efficiency, uneven distribution and high motor power.

The core technology of the screening machine is that the screening efficiency is high and low and whether the material distribution on the screen surface is uniform. The screening machine can provide safer and feasible performance guarantee for the follow-up crusher when meeting the two conditions simultaneously.

Therefore, the most core technologies of the coal making system are the screening efficiency of the screening machine and the type selection of the crusher.

In view of the technical performance of the various crushers and screening machines, the industry is configured according to output, and a 4-layer crushing building, namely a fine screening and fine crushing structure, is adopted in a coal making system with the output of 300 t/h. The screening, crushing and shape selection configuration difference is large, the discharging particle size dipolar differentiation is serious, and the operation management is poor.

The coal-making system adopts 4 layers of two crushing buildings, namely a coarse crushing building and a fine crushing building which are arranged in a double-line mode, wherein the output of the coal-making system is 300 plus 800 t/h. The coarse screen is generally a roller screen or a vibrating screen, the ring hammer crusher is used for coarse crushing, the feed particle size is 0-300mm, and the screening crushing particle size is 0-50 mm. The fine crushing building adopts a roller screen or a vibrating screen, and the fine crusher adopts a reversible crusher. The particle size of the crushed materials is 0-13 mm. This system arrangement creates two problems: one is repeated crushing (the proportion of thickness deviation is large), and the second problem is that the reversible crusher can generate crushing escape (crushing is released) in the crushing process. The discharged grain diameter is 8-35% out of standard.

The coal preparation system 800-; the output of the ring hammer type crusher is 800t/h, and the crushing grain diameter is 0-50 mm. The fine crushing building adopts a 40-meter high 6-layer fine crushing building, and a secondary fine screening fine crushing and a third-level fine screening fine crushing are arranged in the crushing building to solve the problem of over standard particle size. A vibrating screen or a roller screen is arranged in the fine crushing building, the output force is 1000t/h, and the screening grain size is 0-13 mm; the output of the reversible crusher (inlet crusher) is 600-. (during crushing, a small part of unqualified particle size is escaped or released due to various reasons such as coal materials)

Therefore, the problem that the large particle size is released when the part of the fine crusher escapes is solved, three-stage screening is needed to be arranged below a discharge port of the fine crusher, the three-stage screening is a vibrating screen or a roller screen, the output force is 600-; the screened escaping excessive grain size is crushed to qualified grain size by a reversible crusher below, and the reversible crusher outputs 300 t/h; the crushed particle size is 0-13 mm.

The output of various coal conveying and producing systems of various circulating fluidized bed enterprises at present is more than 300t/h, and two crushing buildings with a two-sieve two-crushing structure, namely a coarse crushing building and a fine crushing building are adopted. The output is over 800t/h, so that a three-sieve three-crushing design scheme is adopted for ensuring both the output and the particle size. In the aspects of equipment type selection and process, too, because purchasing procedures are complicated and exist in many unreasonable places, the equipment output is insufficient, and the particle size exceeds the standard.

The high-end crusher technology with the crushing grain size of 8-10mm is almost all products of America and Germany factories when the output of coal conveying and producing systems of thermal power plants in China is more than 500t/h, and the existing factories break through the bottleneck of the high-end screening technology in China. The combination of the screening and the crushing can achieve the effect of getting twice the result with half the effort.

At present, a small part of domestic circulating fluidized bed boiler power plants realizes that the worse the heating value of gangue, the more strict the particle size requirement, the more doped impurities and the more strict the particle size requirement. The output of the crusher for crushing the coal gangue in the prior art at home at present is 500t/h, the grain diameter is 0-10mm, three enterprises already enter the edge of the broken product, and more than 500t/h are huge monopolies abroad.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provides a step-by-step decrement coal preparation system. The system solves the problem of repeated crushing of materials, reduces the construction cost and equipment acquisition cost of a crushing building, can realize the purpose of energy conservation and efficiency improvement for a long time, and solves the problems of excessive grain size and output of coal as fired for a coal conveying and making system of a boiler.

The purpose of the invention is realized by the following technical scheme:

the step-by-step reduction coal preparation system comprises an A-line main belt conveyor, a B-line main belt conveyor and a C-line belt conveyor, wherein the A-line main belt conveyor and the B-line main belt conveyor are respectively arranged right below a coal outlet of a coal yard, screening machines are respectively arranged on the A-line main belt conveyor and the B-line main belt conveyor, undersize qualified particle size materials of the screening machines are respectively conveyed to a boiler bin through the A-line main belt conveyor and the B-line main belt conveyor, and oversize unqualified particle size materials of the screening machines are conveyed to the top of a fine crushing building through the C-line belt conveyor;

the fine crushing building in be equipped with two sets of broken devices of sieve, be provided with the coal plough that is used for switching two sets of broken devices of sieve on the C line belt feeder, every broken device top-down of group includes coarse crusher, second grade screening machine and fine crusher, unqualified particle diameter material falls to the coarse crusher by the belt feeder of C line conveying to the top floor layer of fine crushing building layer, fall to second grade screening machine after the coarse crusher is broken, qualified particle diameter material correspondence that the second grade screening machine sieved drops to A line owner belt feeder, B line owner belt feeder, carry to boiler feed bin after meeting, unqualified particle diameter material that the second grade screening machine sieved the thing falls to the fine crusher, qualified particle diameter material after the fine crushing drops to A line owner belt feeder, B line owner belt feeder, carry to boiler feed bin after meeting.

And the upper end of the C-line belt conveyor is provided with a standby coal outlet, and when the screening machines on the A-line main belt conveyor and the B-line main belt conveyor fail, coal is fed on the C-line belt conveyor.

The coal plough is arranged on the C-line belt conveyor above the feeding port of the coarse crusher of the previous group of screening and crushing devices.

The screening machine and the secondary screening machine include but are not limited to: roller screens, cross screens, sinusoidal screens, screening distributors, vane screens, cascade screens, vibrating screens, high-amplitude screens, comb tooth swinging screens, toothed roller screens, double-rotary screens or spiral screens.

The C-line belt conveyor is arranged between the A-line main belt conveyor and the B-line main belt conveyor.

And materials with unqualified oversize grain diameters of the screening machine are conveyed to a C-line belt conveyor through a coal dropping pipe, a vibrating feeder, a belt conveyor, a scraper conveyor or a chain bucket conveyor.

The coal dropping pipe is provided with a vibration beater.

The technology of the invention is a coal preparation system with output of 300-1500 t/h: the 18-meter 5-layer crushing building is adopted, the fine screen is arranged in the space between the coal hopper and the belt conveyor in the coal yard, and the screening efficiency of the fine screen can be adjusted to 75-99%. The process flow is as follows: the output of a coal preparation system is set to be 1000t/h, and the qualified particle size in the incoming material accounts for 65 percent. 1000t/h of coal material enters from the A/B line coal grate, a screening machine with the output of 1000t/h is arranged on a belt conveyor right below the coal grate, 65 percent of qualified particle size in 1000t/h is screened out by the screening machine, namely the qualified particle size is 650 t/h; the qualified particle size of the 650t/h undersize product is directly conveyed to a boiler bin by an A/B line belt conveyor; and the unqualified grain diameter of 350t/h oversize products larger than 10mm is conveyed to a belt incoming layer of a fine crushing roof layer by a C-line belt conveyor and falls to a coarse crusher, the output of the coarse crusher is 400t/h, the crushed grain diameter is 30-35mm, and the qualified grain diameter of 0-10mm accounts for 60 percent after being crushed by the coarse crusher, namely the qualified grain diameter of 210 t/h. And secondary screening equipment is arranged below the coarse crusher layer, the coal after coarse crushing at 350t/h enters a secondary screening machine, the output of the secondary screening machine is 400t/h, and the screening particle size is 0-10 mm. The coal materials with qualified particle size of 210t/h screened by the secondary screening machine directly fall onto a corresponding main belt conveyor of the A/B line through a coal dropping pipe and are conveyed to a boiler in a gathering way. And (3) dropping 10-35mm of oversize products screened by the secondary screening machine into an anti-escape ring hammer machine of a fine crushing layer through a coal dropping pipe, and finely crushing the oversize products to 0-10mm of particle size. The force of the anti-escape ring hammer type fine crusher is 200t/h, the crushed particle size is 0-10mm, the anti-escape ring hammer type fine crusher finely crushes the coal to be 0-10mm qualified particle size, the coal is directly dropped to a main leather machine corresponding to an A/B line of a 0m layer through a coal dropping pipe, and the coal is conveyed to a boiler to complete a 1000t/h step-by-step decrement coal preparation process.

A screening machine is arranged on a belt conveyor right below a coal bucket coal grate in a coal yard, and the qualified particle size of screened undersize materials enters a boiler bin through an A/B main belt. The oversize (unqualified particle size) falls to another belt conveyor, enters a crushing plant, is coarsely crushed, finely sieved and finely crushed to reach the qualified particle size, and is converged with an A/B main belt to enter a boiler bin.

It is well known that: the proportion of qualified 0-10mm particle size in a coal yard is generally 40-85%, and is usually about 65%.

The core process route of the step-by-step coal reduction process is as follows: the qualified particle size is screened and crushed step by step, the subsequent output force of equipment is reduced step by step, the system structure is simplified, and the excessive particle size of fine powder generated by repeated crushing is reduced.

Example (c): the qualified grain diameter of 0-10mm in the coal yard accounts for 65 percent, and the output of the belt conveyor equipment is 1000 t/h.

The step-by-step decrement coal preparation process flow comprises the following steps: 1000t/h coal material enters from an A/B line coal grate, a screening machine with the output of 1000t/h is arranged on a belt conveyor right below the coal grate, a discharge port of the screening machine is divided into two paths, and one path is 0-10mm qualified particle size of undersize materials and is directly conveyed to a boiler by an A/B main belt conveyor; and the unqualified grain diameter of 10-300mm of the other path of oversize products is conveyed to a fine crushing building by a C-line belt conveyor, and the qualified grain diameter is obtained after crushing and screening until the corresponding A/B-line main belt conveyor is converged to a boiler bin to complete the whole process.

Namely: 1000t/h of coal material enters from the A/B line coal grate, a screening machine with the output of 1000t/h is arranged on a belt conveyor right below the coal grate, 65 percent of qualified particle size in 1000t/h is screened out by the screening machine, namely the qualified particle size is 650 t/h; the qualified particle size of the 650t/h undersize product is directly conveyed to a boiler bin by an A/B line belt conveyor; and the unqualified grain diameter of 350t/h oversize products larger than 10mm is conveyed to a belt incoming layer of a fine crushing roof layer by a C-line belt conveyor and falls to a coarse crusher, the output of the coarse crusher is 400t/h, the crushed grain diameter is 30-35mm, and the qualified grain diameter of 0-10mm accounts for 60 percent after being crushed by the coarse crusher, namely the qualified grain diameter of 210 t/h. And secondary screening equipment is arranged below the coarse crusher layer, the coal after coarse crushing at 350t/h enters a secondary screening machine, the output of the secondary screening machine is 400t/h, and the screening particle size is 0-10 mm. The coal materials with qualified particle size of 210t/h screened by the secondary screening machine directly fall onto a corresponding main belt conveyor of the A/B line through a coal dropping pipe and are conveyed to a boiler in a gathering way. And (3) dropping 10-35mm of oversize products screened by the secondary screening machine into a ring hammer type fine crusher in a fine crushing layer through a coal dropping pipe, and finely crushing the oversize products to 0-10mm of particle size. The output of the ring hammer type fine crusher is 200t/h, the crushed particle size is 0-10mm, the ring hammer type fine crusher is used for fine crushing to reach the qualified particle size of 0-10mm, and the crushed particles are directly dropped to the main leather machine corresponding to the A/B line of the 0m layer through the coal dropping pipe and are conveyed to the boiler to complete the 1000t/h step-by-step decrement coal preparation process.

As a preference: a screening machine is arranged right above the A/B line belt conveyor below the underground coal hopper and is a fine screen, and the output of a single machine is 5-5000 t/h.

As a preference: a screening machine is arranged right above the A/B line belt conveyor below the underground coal hopper and is a fine screen.

The screening machine is preferably arranged right above the A/B line belt conveyor below the coal hopper, and the screening machine is not limited to 1-4.

The oversize material refers to: unqualified particle size; the undersize means the acceptable particle size. The fine material refers to a qualified particle size. Coarse material refers to an unqualified particle size.

The screening machine is not limited to: roller screens, cross screens, sinusoidal screens, screening distributors, vane screens, cascade screens, vibrating screens, spiral screens and the like.

The C-line coal conveying belt conveyor is preferably positioned in the middle of the A/B-line belt conveyor. Nor on both sides of the a/B line belt machine.

The A/B belt conveyor can also be called an A/B line belt coal conveyor or an A/B line coal conveying system and an A/B line coal conveying and making system.

As a preference: the particle size of the coal fed into the boiler is generally 0-10mm, but is not limited to the fluctuation of the particle size of the discharged material of a screening or crushing device in the range of 6-50 mm.

The step-by-step coal reduction process is provided with on-site and remote interlocking start-stop control.

The screening and crushing system is characterized by comprising: the crushing building, the screening machine, the belt conveyor and the coal dropping pipe are combined.

The screening and crushing equipment is characterized in that: screening machine, breaker.

The coarse grain size screened by the ground coal hopper fine screening machine can adopt a coal chute (coal dropping pipe) and can also adopt other modes to convey coal materials, such as a vibrating feeder, a belt conveyor, a scraper, a chain bucket machine and the like.

The screening and crushing equipment refers to screening and crushing equipment and is also called screening and crushing equipment, and the screening and crushing equipment is not limited to a combination of the screening equipment and the crushing equipment: screening and crushing integrated machine.

The coarse screening means screening particles with the particle size of 20-150 mm, and similarly, the crushing particle size of coarse crushing equipment is 20-150 mm; the particle size range of the fine screening and fine crushing equipment is 0-20 mm.

The screening machine is not limited to screening distributors, rotary screens, roller screens, impeller cascade screens, vibrating screens, high-amplitude screens, sine screens, comb tooth swing screens, cross screens, toothed roller screens, spiral screens, double-rotary screens and other types of screening equipment.

The crusher is not limited to ring hammer crushers, escape-proof crushers, non-clogging crushers, toothed roll crushers, impact hammer crushers and other crusher types.

The materials are not limited to coal, chemical raw materials, metallurgical ores, coke, grains and the like.

The belt conveyor is not limited to common belt conveyors, pipe belt conveyors, corrugated flange belt conveyors and the like.

The coal yard is a dry coal shed of a power plant and is not limited to a coal silo and an open coal yard.

The preferred coal grate is arranged in a coal yard, the shape of the coal grate is square, round and bar, and the size of the coal grate is between 100 and 1000 mm.

The preferable C-line belt conveyor is not limited to one belt conveyor, and is used for conveying unqualified particle sizes screened by an A/B screening machine below a coal hopper in a conveying way, and conveying coal to a fine crushing building by a spare line.

As an optimized technology, the high-efficiency and energy-saving screening shaft type screening distributor is adopted as fine screening equipment. The screening efficiency of the equipment is 5-12 times of that of the same equipment under the condition that the volume, the power and other parameters of the equipment are equal to those of the same equipment, and the screening efficiency is adjustable.

As a preferred mode of the technology, the escape-proof ring hammer crusher is a fine crushing device.

The device is preferably provided with a vibration beater for preventing coal blockage on the coal dropping pipe, and the vibration beater is not arranged on the coal dropping pipe if the coal blockage is not caused.

1 to 10 spare coal hoppers can be arranged as a preferable C line according to the needs of users. The coal falling from the standby coal hopper is directly conveyed to a crushing building for crushing.

The preferred coal plough is an electric coal plough or a hydraulic coal plough, and is not limited to other types of scraping plates.

The process as a preferred coal bunker section is: the coal bin is connected below the coal grate, the fine screen is connected below the coal bin, an A/B line qualified particle size belt conveyor is arranged below the fine screen, a C line belt conveyor is arranged between the A/B line belt conveyors, undersize of the screening machine is conveyed in two ways, the qualified undersize falls to the A/B line qualified particle size belt conveyor to convey coal to a boiler, and the unqualified undersize falls to the C line belt conveyor to enter a fine crushing building to be crushed.

The process as a preferred fine building part is as follows: after the C-line belt conveyor conveys coal materials to the top layer of the fine crusher, the coal plough arranged on the C line is put down and is lifted to switch an A/B line device to screen and crush unqualified and thick coal blocks, and the screened and crushed coal materials with qualified particle sizes fall to the A/B line and are converged to a boiler bin.

Preferably, a coal plough is arranged on the conveyor on the line C, the coal plough is positioned on the belt conveyor on the line C above the feeding hole of the coarse crusher, and the coal plough is used for the related operation on the line A when the coal plough is put down (the coarse unqualified particle size coal enters the coarse crusher on the line A), and the coal plough is used for the related operation on the line B when the coal plough is lifted.

When the belt conveyor is used as a preferable A/B/C line belt conveyor to convey to a ground level zero meter layer, two paths of coal conveying are carried out, wherein one path is that A/B coal conveying is carried to the bottom of a fine crushing building along the ground level, and the other path is that C line is carried to the top of the fine crushing building along a certain angle (1-90 degrees).

The C-line belt conveyor has two functions: the coal on the A/B sieve is conveyed to the fine crushing building under normal conditions, and the coal in the spare coal hopper is conveyed to the fine crushing building for sieving and crushing under abnormal conditions.

Preferably, AB line coal feeding is adopted, when coal feeding is carried out on the coal A line in a coal yard, coal is discharged from a coal grate on the A line, qualified particle sizes smaller than 10mm after being screened by a fine screen on the A line are directly conveyed to a boiler bin on the A line from the A line, unqualified coal particles larger than 10mm are crushed to qualified particle sizes from a coal conveying line on a fine crushing building on a C line, and then the unqualified coal particles fall on the A line through an outlet material of a screening and crushing device and are conveyed to a boiler together with the qualified particle sizes after primary screening.

And the line C is a spare line, and when the AB sieving machines below the coal hopper break down, coal is fed on the line C. The output of the coal feeding on the C line is reduced by half compared with the output of the coal feeding on the original AB line. The boiler is ensured to be free from coal breakage, and wider time is provided for rush repair of AB line fine screens.

The traditional 1000-ton output coal output system needs: two crushing buildings, 6 belt conveyors, 12 sets of screening and crushing equipment and 6 sets of auxiliary hoisting and dust removing equipment. The technology is adopted as follows: a crushing building comprises 3 belt conveyors, 8 sets of screening and crushing equipment and 4 sets of attached hoisting and dust removing equipment. The following table tabulates and compares a conventional coal conveying and producing system with the coal conveying and producing system of the present invention.

The present invention solves the following four problems:

(1) solves the problem of repeated crushing of coal as fired.

(2) The problem of repeated investment of the capital construction crushing building is solved.

(3) The problem of the configuration structure of the traditional equipment for model selection is solved.

(4) The problems of high energy consumption, detection and maintenance and the like of equipment in long-term operation are solved.

Drawings

FIG. 1 is a front view of the position relationship of a coal hopper screening belt conveyor of the present invention;

FIG. 2 is a left side view of the position relationship of the coal hopper screening belt conveyor of the present invention;

FIG. 3 is a schematic view of the step-by-step coal reduction process of the present invention

FIG. 4 is a front view of a fine crushing building process arrangement of the present invention

FIG. 5 is a left side view of a fine crushing building process arrangement of the present invention

In the figure, 1-a coal yard, 2-a coal grate, 3-a coal bunker, 4-a sieving machine, 5-a/B line main belt conveyer, 6-C line belt conveyer, 7-a shaking beater, 8-C line spare coal dropping hopper, 9-a coal plough, 10-a coarse crusher, 11-a secondary sieving machine and 12-a fine crusher.

Detailed Description

The process of the present arrangement is further described below with reference to the accompanying drawings and examples:

as shown in figures 1 and 2, a screening machine is arranged on a coal hopper A/B belt conveyor and mainly has the function of screening qualified-particle-size coal to the greatest extent so as to provide necessary conditions for reducing and saving energy of subsequent equipment. The position relationship is as follows: a ground coal hopper is arranged in the coal yard, the ground coal hopper is divided into two types, one type is an A/B line common ground coal hopper, and the other type is a C line standby coal supply ground coal hopper. The upper part of the underground coal hopper and the ground level are provided with coal grates, the lower part of the underground coal hopper is connected with a screening machine (fine screen), qualified particle sizes of undersize materials drop to an A/B belt conveyor respectively, and unqualified particle sizes of oversize materials drop to a C-line belt conveyor through a coal chute to be crushed in a fine crushing building. The vibrator is arranged on the coal chute to prevent the coal chute from blocking coal to affect production.

As shown in the figures 3 and 4, a coal plough is arranged on the conveyor on the line C, the coal plough is positioned on the belt conveyor on the line C above the feeding hole of the coarse crusher, and the coal plough is used for putting down the equipment on the line A for operation (the coarse unqualified-particle-size coal enters the coarse crusher on the line A), and the coal plough lifts up the equipment on the line B for operation.

When the belt conveyor with the line A/B/C shown in FIG. 3 conveys coal to the ground level and the zero meter layer, two paths of coal are conveyed, wherein one path is the coal conveyed from the line A/B to the bottom of the fine crushing building and the boiler bin along the ground level, and the other path is the coal conveyed from the line C to the top of the fine crushing building along a certain angle (1-90 degrees).

Fig. 4 and 5 show a fine crushing building process arrangement structure, a C-line belt conveyor is used for feeding coal, a coal plough is arranged on the C-line belt conveyor, the coal plough can switch an A/B line screening and crushing system in a crushing building, when the A-line screening and crushing system is used, the coal plough is put down, coal enters an A-line coarse crusher, the coal is crushed by the coarse crusher and then is screened by a screening machine (fine screen) and then is divided into two paths, one path is qualified particle size and falls onto the A-line belt conveyor, the other path is unqualified coarse coal blocks and falls onto a fine crusher to be crushed again to be qualified particle size, and the qualified particle size after fine crushing falls onto the A-line belt conveyor to be converged and conveyed to a boiler bin.

The working principle and process of the embodiment of the invention are as follows:

as shown in fig. 1, 2, 3, 4, and 5: setting incoming materials at 1000 t/h; a fine screen is arranged right below a coal hopper (right above an A/B belt conveyor) with the grain diameter of less than 10mm accounting for 60% of the supplied materials, qualified grain diameters of undersize materials fall to the corresponding A/B belt conveyor, and the qualified coal materials are conveyed to a boiler bin through the belt conveyor. The method comprises the following steps that unqualified coal materials on a screen of a screening machine fall onto a C-line belt conveyor from a coal chute, a vibrator is arranged on the coal chute, the coal materials with unqualified particle sizes are conveyed to a fine crushing building from the C-line belt conveyor, a coal plough is arranged on the C-line belt conveyor, two groups (sets) of screening crushing equipment of an A/B line is arranged in the fine crushing building, when the coal plough of the C line is put down, the coal materials fall into an A-line coarse crusher, the particle sizes of most of the coal materials are qualified after being crushed by the coarse crusher, a fine screening machine is arranged below the coarse crusher, the qualified particle sizes screened out by the fine screening machine fall onto a corresponding A-line main belt conveyor and are conveyed to a boiler coal bin, a small part of the coal materials with unqualified particle sizes screened out by the fine screening machine is crushed by a fine crusher below the fine screening machine, the fine screening machine is crushed to the qualified particle sizes and then falls.

Line A of the first process: as shown in fig. 1, 2, 3, 4, and 5: setting incoming materials at 1000 t/h; the grain diameter of less than 10mm in the supplied materials accounts for 60 percent.

A screening machine (fine screen) is arranged under the coal hopper on the line A, the screening particle size is 0-10mm, and the screening machine screens qualified coal materials smaller than 10mm to the full extent: 600t/h, the qualified particle size of the undersize product 600t/h falls onto a 1# A line main belt conveyor, and the 1# A line belt conveyor directly conveys the coal material with the qualified particle size of 600t/h to a boiler bin through a bottom layer of a fine crushing floor. 400t/h unqualified coal materials with the particle size larger than 10mm on a sieving machine are dropped onto a No. 1C line of another belt conveyer through a coal chute, the unqualified coal materials are conveyed to a fine crushing top floor layer by a C line belt conveyer, a coal plough is arranged on the C line belt conveyer, the coal plough is put down, the coal materials are dropped into an A line coarse crusher to be crushed, 60% qualified coal materials with the particle size, namely 240t/h qualified coal materials, can be generated after being crushed by the coarse crusher, a fine sieving machine is arranged below the coarse crusher, the fine sieving machine sieves 240t/h qualified coal materials out of undersize materials, the sieved qualified coal materials drop onto a corresponding A line main belt conveyer through a coal chute below the fine sieving machine and are conveyed to a boiler bin together with the first-sieved qualified coal materials with the particle size of 600 t/h; oversize materials 160t/h screened out by the fine screening machine fall into a fine crusher below through a coal dropping pipe to be crushed, the fine crusher crushes the 160t/h coal materials to qualified particle sizes (0-10 mm), and then falls onto a No. 1A belt conveyor to be converged and conveyed into a boiler bin, so that the A line step-by-step coal reduction process is completed.

And (2) a second process line B: as shown in fig. 1, 2, 3, 4, and 5: setting incoming materials at 1000 t/h; the grain diameter of less than 10mm in the supplied materials accounts for 60 percent.

A screening machine (fine screen) is arranged under the coal hopper on the line B, the screening particle size is 0-10mm, and the screening machine screens qualified coal materials smaller than 10mm to the full extent: 600t/h, the qualified particle size of the undersize product 600t/h falls onto a 1# B line main belt conveyor, and the 1# B line belt conveyor directly conveys the coal material with the qualified particle size of 600t/h to a boiler bin through a bottom layer of a fine crushing floor. 400t/h unqualified coal material with the particle size larger than 10mm on a screen of the screening machine falls onto a No. 1C line of another belt conveyor through a coal chute, the unqualified coal material is conveyed to a fine crushing top floor layer by a C line belt conveyor, a coal plough is arranged on the C line belt conveyor and lifted, the coal material falls into a B line coarse crusher to be crushed, 60% qualified coal material with the particle size, namely 240t/h qualified coal material, is generated after being crushed by the coarse crusher, a fine screening machine is arranged below the coarse crusher, the fine screening machine screens out the 240t/h qualified coal material with the particle size from the undersize material, falls onto a corresponding A line main belt conveyor through a coal chute below, and is conveyed to a boiler bin together with the first screened 600t/h qualified coal material; the oversize material 160t/h of the fine sieve falls into a fine crusher below through a coal dropping pipe to be crushed, the fine crusher crushes the 160t/h coal material to a qualified particle size (0-10 mm), and then falls onto a No. 1B belt conveyor to be converged and conveyed into a boiler bin, so that the B-line step-by-step decrement coal preparation process is completed.

And a third process: the C line process is a spare line, coal conveying and production protection are needed when an A/B line fine screening machine below a local coal hopper is overhauled and maintained at the same time, and coal on the C line can be started. The coal feeding amount can be reduced by half. Namely the coal feeding amount is 500 t/h. As shown in fig. 1, 2, 3, 4, and 5: the coal material of 500t/h is discharged from a coal hopper on the C line and falls onto a belt conveyor on the C line, the belt conveyor on the C line conveys the coal material of 500t/h to a fine crushing building for crushing, an A/B line screening and crushing process is selected by switching a coal plough on the C line, the A line screening and crushing process is carried out when the coal plough is put down, and the B line coal feeding process is carried out when the coal plough is lifted. The coal material of 500t/h enters the A line, the coal material of 500t/h generates 80 percent of qualified particle size after coarse crushing, namely 400t/h qualified particle size, the fine screen machine with 500t/h output is arranged below the coarse crusher, the fine screen completely screens 400t/h qualified particle size of undersize products, then the undersize products drop to the belt conveyor of the A line through the coal dropping pipe to convey coal to a boiler bin, the coal material of 100t/h unqualified particle size drops to the fine crusher through the coal dropping pipe to be finely crushed to qualified particle size, and the qualified particle size after fine crushing drops to the belt conveyor of the A line through the coal dropping pipe to be conveyed to the boiler bin together.

Although the present invention has been described in detail with reference to the preferred embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the spirit and scope of the present invention as defined in the appended claims.

Claims

1. Decrement system coal system step by step, its characterized in that: the screening machine comprises an A-line main belt machine, a B-line main belt machine and a C-line belt machine, wherein the A-line main belt machine and the B-line main belt machine are respectively arranged under a coal outlet of a coal yard, screening machines are respectively arranged on the A-line main belt machine and the B-line main belt machine, qualified particle size materials below a screen of the screening machines are respectively conveyed to a boiler bin through the A-line main belt machine and the B-line main belt machine, and unqualified particle size materials above the screen of the screening machines are conveyed to the top of a fine crushing building through the C-line belt machine;

2. The system for progressive de-weighting coal as claimed in claim 1, wherein: and the upper end of the C-line belt conveyor is provided with a standby coal outlet, and when the screening machines on the A-line main belt conveyor and the B-line main belt conveyor fail, coal is fed on the C-line belt conveyor.

3. The system for progressive de-weighting coal as claimed in claim 1, wherein: the coal plough is arranged on the C-line belt conveyor above the feeding port of the coarse crusher of the previous group of screening and crushing devices.

4. The system for progressive incremental reduction of coal as claimed in claim 1, wherein: the screening machine and the secondary screening machine include but are not limited to: roller screens, cross screens, sinusoidal screens, screening distributors, vane screens, cascade screens, vibrating screens, high-amplitude screens, comb tooth swinging screens, toothed roller screens, double-rotary screens or spiral screens.

5. The system for progressive de-weighting coal as claimed in claim 1, wherein: the C-line belt conveyor is arranged between the A-line main belt conveyor and the B-line main belt conveyor.

6. The system for progressive de-weighting coal as claimed in claim 1, wherein: materials with unqualified particle sizes on the screen of the screening machine are conveyed to the C-line belt conveyor through a coal dropping pipe, a vibrating feeder, a belt conveyor, a scraper conveyor or a chain bucket conveyor.

7. The system for progressive de-weighting coal as claimed in claim 1, wherein: the coal dropping pipe is provided with a vibration beater.

8. The system for progressive de-weighting coal as claimed in claim 1, wherein: and when the A/B/C line belt conveyor conveys the coal to a zero-meter floor on the ground level, two paths of coal conveying are carried out, wherein one path is to convey the A/B with qualified particle size to the bottom of a fine crushing building along the ground level, and the other path is to convey the C line with unqualified particle size to the top of the fine crushing building along a certain angle (1-90 degrees).