CN202935946U - Efficient positive-pressure pneumatic conveying system of pebble coal - Google Patents

Abstract

The utility model relates to a high-efficiency pebble coal positive pressure pneumatic conveying system used for pebble coal discharge from a medium-speed coal mill in a thermal power plant. The high-efficiency pebble coal positive pressure pneumatic conveying system includes a pebble coal bunker whose upper end is connected to the pebble coal outlet of the medium-speed coal mill, the lower end of the pebble coal bunker is connected to a feeding device, and the front inlet of the feeding device is connected to a compressed air pipeline , the rear outlet of the feeding device is connected to the pebble coal hopper through the conveying pipeline, and the gas outlet of the pebble coal hopper is exhausted through the dust collector. The utility model solves the shortcomings of the original negative pressure pneumatic conveying system. The whole system has low energy consumption, low noise, high reliability and strong conveying capacity; the use of loose air ducts can strengthen the conveying capacity of the system, and at the same time ensure that the system is safe when failure occurs. Solution: The gravel coal bunker vibrating screen can effectively remove materials that are not suitable for pneumatic conveying and ensure that the system does not jam.

Description

High-efficiency pebble coal positive pressure pneumatic conveying system

technical field

The utility model relates to a high-efficiency pebble coal positive pressure pneumatic conveying system used for pebble coal discharge from a medium-speed coal mill in a thermal power plant. the

Background technique

Medium-speed coal mills are widely used in power plant boiler units due to their low investment and good economy. The medium-speed coal mill will produce pebble coal during operation. The pebble coal mainly comes from gangue, pyrite, etc., which are dense and difficult to grind in the raw coal. When the coal mill is running, it falls below the wind ring, is sent into the pebble coal hopper by the scraper, and is discharged from the pebble coal discharge port at the lower part. . If the pebble coal is not discharged in time, it will accumulate in a large amount in the coal mill, which will easily cause the coal mill to fail and shut down. the

Pebble coal is mainly composed of gangue, crushed coal, stones, coal powder and other sundries, the particle size is generally not greater than 50mm, the bulk density is 1.0~1.5 t/m3, and the temperature is generally around 150°C. Due to the characteristics of high density, large particles, high hardness, high temperature, and dust content, pebble coal has certain difficulties in handling and transportation. There are three types of common pebble coal discharge: manual discharge, hydraulic discharge, and mechanical conveyance discharge. At present, due to the variety of coal types in power plants, the quality of raw coal generally deteriorates. The amount of stones, gangue, ore and other sundries in raw coal has increased compared with before, and the discharge of pebble coal has greatly increased, which seriously affects the safe operation of thermal power plants. Conventional pebble coal discharge methods It is difficult to solve the problem that the amount of pebbles and coal increases greatly at present. the

Recently, a small number of power plants in China have transformed the treatment of pebble coal into a negative pressure pneumatic conveying system. Using moving air as the medium to convey materials is a transportation method that has long been used in industry, and is called pneumatic conveying. Pneumatic conveying system is divided into positive pressure conveying and negative pressure conveying according to the working pressure of the medium used. Negative pressure pneumatic conveying has obvious advantages compared with conventional pebble coal discharge methods. The actual application results also show that it can basically meet the requirements of power plant pebble coal Coal emission requirements. the

However, the negative pressure pneumatic conveying system also has obvious shortcomings, the main problems are as follows:

1. The negative pressure pneumatic conveying system needs a high-power Roots blower as the power source, which has high energy consumption;

2. The air velocity at the end of the system is high, which is very easy to cause wear and tear on the pipeline and equipment, resulting in the failure of the system to work normally;

3. Most of the screw feeders still use the screw feeder as the pebble coal feeding tool, which cannot be transported for large-size pebble coal. As the rotating part, the screw feeder is very prone to failure and wear when conveying the pebble coal;

4. The effective dynamic pressure difference of the negative pressure system is at most one atmospheric pressure, which limits the conveying capacity of the pneumatic conveying system;

5. The noise of the Roots blower is very loud, which becomes a new noise source of the power plant.

Traditional positive pressure pneumatic conveying systems generally use bin pumps or screw feeders as feeding equipment. Due to the special physical characteristics of pebble coal, it is difficult for bin pumps and screw feeders to achieve normal feeding of pebble coal. the

Contents of the invention

The technical problem to be solved by the utility model is to provide a high-efficiency pebble coal positive pressure pneumatic conveying system with low energy consumption, low noise and good conveying stability. the

The high-efficiency pebble coal positive pressure pneumatic conveying system of the utility model includes a pebble coal bunker whose upper end is connected to the pebble coal outlet of the medium-speed coal mill, and a feeding device connected to the outlet of the lower end of the pebble coal bunker, and the front end inlet of the feeding device is connected The compressed air pipeline and the rear outlet of the feeding device are connected to the pebble coal hopper through the conveying pipeline, and the gas outlet of the pebble coal hopper is exhausted through the dust collector. the

A section of communicating pipe is connected between the compressed air pipeline and the upper space of the gravel coal bunker to maintain positive pressure in the gravel coal bunker. the

A vibrating screen is arranged between the upper inlet and the lower outlet of the pebble coal bunker to separate large pebble coal that is not suitable for pneumatic conveying. the

Different conveying sections of the conveying pipeline are provided with several loose air ducts equipped with valves, which are used to introduce loose airflow when necessary to prevent material deposition. the

An openable and closable access door is provided on the lower wall of the gravel coal bunker for cleaning and maintenance. the

The feeding device includes a feed bin, the top of the front section of the feed bin is provided with a feed inlet, and a horizontal partition plate is arranged in the middle of the front section of the feed bin; The upper air inlet is connected to the compressed air pipe through a section of feeding air pipe, and the lower air inlet is connected to the compressed air pipe through a section of conveying air pipe. Both the feeding air pipe and the conveying air pipe are equipped with flow rate Adjusting device; the rear end of the feed bin is provided with a discharge port connected to the pebble coal conveying pipeline. A receiving hopper is arranged on the feed inlet, and a pulse loosening pipe which can lead to a pulse air flow is connected to the side wall of the receiving hopper. The rear section of the feed bin is provided with a horizontal springboard located at the rear and lower part of the partition plate. the

The high-efficiency pebble coal positive pressure pneumatic conveying system of the utility model solves the shortcomings of the original negative pressure pneumatic conveying system. The whole system has low energy consumption, low noise, high reliability and strong conveying capacity; the use of loose air ducts can strengthen the system conveying ability, and at the same time ensure that the system has a solution in case of failure; the gravel coal bunker vibrating screen can effectively remove materials that are not suitable for pneumatic conveying, and ensure that the system does not jam. The feeding device does not use any rotating parts, and has high reliability; the feeding speed of pebble coal can be controlled by adjusting the compressed air flow in the feeding air pipe, and the amount of conveying medium can be controlled by adjusting the compressed air flow of the conveying air pipe, so that the system can Fully adapt to the discharge requirements of various rates of pebble coal, and at the same time configure the economical amount of conveying medium, so as to minimize the energy consumption of the entire system; Coal has an initial velocity and is in the area with the highest airflow velocity, which is conducive to the smooth transportation of pebble coal. the

Description of drawings

Fig. 1 is the front structural representation of the utility model embodiment;

Fig. 2 is a top view structural schematic diagram of Fig. 1;

Fig. 3 is the partially enlarged structural schematic diagram of the gravel coal bunker part of the utility model embodiment;

Fig. 4 is a schematic structural view of the feeding device of the present invention.

Detailed ways

As shown in Figure 1-3, the high-efficiency pebble coal positive pressure pneumatic conveying system includes a pebble coal bunker 1 whose upper end is connected to the pebble coal outlet of the medium-speed coal mill, and a feeding device 2 connected to the lower end of the pebble coal bunker outlet. The inlet of the front end of the feeding device 2 is connected to the compressed air pipeline 3, the outlet of the rear end of the feeding device 2 is connected to the pebble coal hopper 5 through the conveying pipe 4, and the gas outlet of the pebble coal hopper is exhausted through the dust collector 6. A section of connecting pipe 7 is connected between the compressed air pipeline 3 and the upper space of the gravel coal bunker 1 to keep positive pressure in the gravel coal bunker. A vibrating screen 11 is arranged between the upper end inlet and the lower end outlet of the stone coal bunker 1 to separate large pieces of stone coal that are not suitable for pneumatic conveying. Different conveying sections of the conveying pipeline 4 are provided with several loose air ducts 41 equipped with valves, which are used to introduce loose airflow when necessary to prevent material deposition. The lower wall of the gravel coal bunker 1 is provided with an openable and closable access door 12 for cleaning and maintenance. the

As shown in Figure 4, the feeding device 2 includes a feed bin 21, the top of the front section of the feed bin is provided with a feed port 22, and a horizontal partition plate 23 is provided at the middle of the front section of the feed bin; the front end of the feed bin is provided with The two air inlets are respectively located above and below the partition plate. The upper air inlet is connected to the compressed air pipeline P through a section of feeding air duct 24, and the lower air inlet is connected to the compressed air pipeline P through a section of conveying air duct 25. Both the material air pipe and the conveying air pipe are provided with a flow regulating device; the rear end of the feed bin is provided with a discharge port 26 connected with a pebble coal conveying pipe. A receiving hopper 27 is arranged on the feeding port 22, and a pulse loosening pipe 28 which can lead to a pulse air flow is connected to the side wall of the receiving hopper. The rear section of the feeding bin is provided with a horizontal springboard 29 positioned at the rear and lower part of the dividing plate 23 . the

Claims (7)

1. The high-efficiency positive pressure pneumatic conveying system for pebble coal is characterized in that it includes a pebble coal bunker (1) whose upper end is connected to the pebble coal outlet of the medium-speed coal mill, and the lower end of the pebble coal bunker is connected with a feeding device (2 ), the front end inlet of the feeding device (2) is connected to the compressed air pipeline (3), and the rear end outlet of the feeding device (2) is connected to the pebble coal hopper (5) through the conveying pipeline (4), and the gas in the pebble coal hopper The outlet is exhausted through the dust collector (6); A section of connecting pipe (7) is connected between the compressed air pipeline (3) and the upper space of the pebble coal bunker (1), so that positive pressure is maintained in the pebble coal bunker. 2. The high-efficiency pebble coal positive pressure pneumatic conveying system according to claim 1, characterized in that: a vibrating screen (11) is set between the upper entrance and the lower exit of the pebble coal bunker (1). 3. The high-efficiency pebble coal positive pressure pneumatic conveying system according to claim 1, characterized in that: several loose air pipes (41) equipped with valves are provided in different conveying sections of the conveying pipeline (4). 4. The high-efficiency positive pressure pneumatic conveying system for pebble coal according to claim 1, characterized in that: the lower wall of the pebble coal bunker (1) is provided with an inspection door (12) that can be opened and closed. 5. The high-efficiency pebble coal positive pressure pneumatic conveying system according to claim 1, characterized in that: the feeding device (2) includes a feeding bin (21), and the top of the front section of the feeding bin is provided with a feeding port ( 22), there is a horizontal partition plate (23) in the middle of the front section of the feed bin; the front end of the feed bin is provided with two air inlets located above and below the partition board respectively, and the upper air inlet passes through a section of feeding air duct (24) It is connected with the compressed air pipe (P), and the air inlet below is connected with the compressed air pipe (P) through a section of conveying air pipe (25). Both the feeding air pipe and the conveying air pipe are equipped with flow adjustment devices; The rear end of the silo is provided with a discharge port (26) connected to the pebble coal conveying pipeline. 6. The high-efficiency pebble coal positive pressure pneumatic conveying system according to claim 5, characterized in that: a receiving hopper (27) is arranged on the feeding port (22), and the side wall of the receiving hopper is connected with a pulse that can be passed through Pulse loose tube (28) for air flow. 7. The high-efficiency pebble coal positive pressure pneumatic conveying system according to claim 5, characterized in that: the rear section of the feeding bin is provided with a horizontal springboard (29) located behind and below the partition plate (23).

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