Mine road network
National Service Hotline
029-85212477
current location: home » Tech » Secondary resource » text

Analyze how to achieve 900,000 tons of coal slime in the year.

Release date:2018-07-01  source:环球破碎机网  Browse times:737
       Coal slime is a low calorific value fuel produced during the washing process of raw coal. Due to the low cost and price of coal slime, the blended coal slime has always been an important means to improve the profitability of circulating fluidized bed units. In 2014, Inner Mongolia Jingtai Power Generation Co., Ltd. was blended. The coal slurry volume is nearly 900,000 tons, and the fuel cost is more than 80 million yuan. The large proportion of coal-fired coal slurry has played a positive role in coal-electricity joint ventures and comprehensive utilization of resources.

First, the current status of the unit

Inner Mongolia Jingtai Power Generation Co., Ltd. is located in Xuejiawan Town, Zhungeer Banner, Erdos City. It is equipped with two 300MW circulating fluidized bed boiler generator sets. The two units were put into operation in February and March 2010 respectively. , Wellhead Power Station, circular economy project.

Second, the source of slime

The coal-fired boiler is bituminous coal, which comes directly from the Yitai Jingyue Suangou Coal Mine in Inner Mongolia. The coal-burning composition includes raw coal, slime and end coal. The raw coal mined in the underground coal mine is crushed and transported to the raw coal silo (10,000 tons of energy storage) for the factory. The coal quality and particle size control are unstable and the meteorite content is large. The slime comes from the coal mine heavy medium coal washing process, which contains two products of coarse coal slurry and fine coal mud. The fine coal mud often contains a large amount of lost magnetic medium. The final coal is crushed to 13mm or less to be washed raw coal after being selected from the acid spur mine. It is mainly used for emergency use.

Boiler coal combustion is mainly operated in the form of a large proportion of raw coal and slime. Through the analysis of the characteristics of the sour slag mud and the characteristics of the local geological structure (the area is mainly sandy soil), the slime can be blended with the raw coal after being dried in the open air for less than 18%, from 2012 onwards. , gradually implement coal blending with coal slurry.

The coal handling system adopts two-stage screening two-stage crushing mode. The system design conveying capacity is 800 tons/hour, and the conveying distance is about 1200 meters. The coal feeding method of the boiler is to directly feed the coal to the coal feeder before the furnace.

Third, the transformation of the screening system

1. Problems with early equipment

The early screening machine adopts double-rotating fine screening machine. After the large proportion of coal slurry is mixed, the screening efficiency of the fine screening machine is low, and the failure rate is high. A large amount of coal slurry enters the fine crusher, which causes the overload of the fine crusher and the wear of the hammer head to be intensified. Events occur frequently.

The coal conveying smashing equipment is seriously blocked and the failure rate is high; the screening efficiency of the fine screening equipment is low, the hammer of the fine crushing machine is affected by the biasing of the feeding, and the wear of the hammer head is intensified. In order to ensure that the amount of coal has to be increased, the gap between the hammer and the crushing plate of the fine crusher has been increased, resulting in deviation of the particle size of the coal entering the furnace. The two-stage differentiation is serious, which brings a series of problems to the combustion adjustment.

Coal hoppers, guide troughs and other parts of the coal handling system are sticky coal and coal plugs, which affects normal coal mining.

The raw coal bunker of the boiler sticks coal and blocks coal, and the coal feeder frequently breaks coal.

The belt machine slips on the coal feeder and does not contribute.

The coal in the coal feeder exits the coal pipe and burns red.

The boiler has a severe cracking deformation at the coal mouth.

2. Cross screen transformation

In order to ensure the boiler's particle size requirements and the long-term operation of the unit, and improve the safety and reliability of the coal handling system, the double-transfer fine screen machine of the coal handling system is replaced with a cross screen during the single-machine operation.

After the transformation of the fine screening machine, the operation effect is better. The blending ratio of the raw coal and the slime controlled by the mixed coal can be stably operated below 1:3, the equipment works well, and the screening efficiency and particle size control are satisfactory.

The amount of coal can reach more than 700 tons. The failure rate of the screening equipment is reduced, and the service life of the fine crusher hammer is extended to ensure the safe and stable operation of the coal conveying system.

Double screen before transformation (left) and cross screen after transformation (right)

Transformed cross screen

Fourth, the operation of refined management

In order to prevent the coal slurry in the coal hopper and #2 belt to #4 belt guide trough after the coal conveying system is started, the coal plugging phenomenon will be caused to the system in an instant, and the following measures are taken:

The coal slurry in the coal hopper must be pulled out before stopping the coal slurry.

Each time the coal is stopped on the silo 15 minutes before the coal is stopped.

Contact the maintenance unit to clean the #2 belt head tribe coal pipe 20 minutes before stopping the coal blending. The coal slurry in the guide tank must be pulled out when the system stops.

In order to ensure the safe and stable operation of the fine screening machine and the fine crushing machine, contact the maintenance unit in time to stop the coal in the fine screening machine and the fine crushing machine after stopping the coal.

For coal handling equipment, coal plugging and abnormal conditions are prone to occur, and system logic optimization is carried out to ensure the safety of the coal handling system equipment.

V. Optimized management of coal feeding system

(1) Optimization and transformation of the original coal bunker air cannon

Before the coal slime is mixed, the raw coal has low water content, there is no coal plugging phenomenon in the original coal bunker, and the coal feeding system is stable in operation; after the coal slime is mixed, due to the high water holding capacity and high viscosity of the slime, frequent coal bunker shed Coal and export coal plugs, the coal feeder operation is extremely unstable, and sometimes even four coal feeders on one side are broken at the same time, which seriously affects the stable operation of the unit.

Through the understanding of coal plugging in the original coal bunker, the main problems are:

1. The original coal bunker installed air cannon has a dead angle, especially the cone section is difficult to effectively cover.

2. The order of the coal cannon air cannon is inconsistent.

3. Failure to achieve automatic control of the air cannon.

Take measures:

1. Install an air cannon on the inlet gate of the coal feeder on the cone section of the original coal bunk which is prone to shed coal.

2. Re-combine the original coal bunker air gun wiring to ensure that the action sequence is consistent from bottom to top, achieving effective dredging.

3. Collect the coal flow signal to the coal machine to realize the automatic control of the air cannon.

Strengthen production management:

1. Pay great attention to the defects of the coal supply system, equate the defects such as the original coal bunker air cannon with the main auxiliary machine defects, and timely find out the timely treatment to ensure the quality of defect processing.

2. It was found that there was a slight shed coal situation, and the coal level operation of the coal bunker was reduced during the low load period, and the coal slurry mixing was stopped, and the air gun was purged.

3. In the April and May of each year, the original coal bunker will be thoroughly cleaned to prevent the bad coal from affecting the summer heavy load operation.

4. Regularly test the original coal bunker air cannon, on the one hand, loosen the corner area of ​​the upper coal seam; in addition, it will facilitate the timely detection of defects and eliminate them.

(2) Coal mining by falling coal pipe

Due to the high cohesiveness of the slime, it gradually accumulates at the turning point of the falling coal pipe. As time increases, it will become bigger and bigger like a snowball until the coal pipe is blocked. The coal is baked by high temperature gas and is hardened. It is difficult to clean up.

The coal slurry is easily burned after being heated by the high-temperature flue gas, and the coal tube is burned red several times.

Before coal accumulation

After accumulating coal

Coal falling point, turning coal, burning red

For the problem of frequent blockage or even red burning at the turning point of the coal feeding pipe at the exit of the coal feeder, two air cannons are added at the turning point of each coal pipe, and the air is controlled by the PLC time according to the dryness and humidity of the mixed coal slurry. The action cycle of the gun ensures that the short-term accumulation of coal in the falling coal pipe can be evacuated in time, effectively avoiding the burning of red coal in the falling coal pipe.


(3) Deformation control of coal mouth
The size of the coal slime is fine, and the coal entering the coal is burned at the coal feeding port. The coal inlet is not cooled due to the unconstrained air volume, the operating temperature is increased, and the coal is disturbed by the coal feeder. The temperature field in this area is extremely unstable. The crack is severely deformed to the coal mouth, causing the nearby wear-resistant plastic to crack or even fall off.

After the integral casting of heat-resistant steel to the coal mouth, the expansion deformation problem has not been effectively solved


.

Cracking deformation of coal mouth

Take measures:
1. Through on-site understanding, the main problem is to solve the combustion advancement, followed by the control of a relatively stable temperature field.
2. In combination with the actual situation, two high-pressure cooling winds are added to the root of each falling coal pipe for on-line purging. The wind source is taken from the high-pressure fluidized wind turbine. After 5 months of retrofitting operation, the furnace was inspected and the coal mouth was kept as it was, and the cracking deformation problem was well controlled.

(4) Slip control of coal feeder belt

After the coal feeder belt is slipped, the surface of the operation table shows that the amount of coal supplied is constant. The parameter indicates that the temperature of the bed on the coal side is decreased, and the oxygen content of the flue gas is increased. If the pressure is reduced before the machine is found, the total coal supply is continuously increased. Big.

The conventional treatment method is to directly adjust the belt by the maintenance personnel; thus, the coal feeder is not accurately metered.

Take the glue to the coal feeder drive wheel to solve the belt slip problem.
Summary

The slime has fine particle size and high content of particles; it has strong water holding capacity and high moisture content; high ash content, low calorific value and high viscosity. Due to these characteristics, it is difficult to stack, store and transport slime. Especially in the case of stockpiling, its shape is extremely unstable, it is lost when it is in contact with water, and the air is dry. The result is not only wasted precious coal resources, but also caused serious environmental pollution.

Rational use of slime to promote strengths and avoid weaknesses. Firstly, it is necessary to make corresponding transformation and optimization on the system equipment. Secondly, it is more important to carry out refined management in combination with the operating characteristics of the system. In this way, the slime will turn waste into treasure, which will bring good economic benefits to the enterprise.

 
 
[ Techsearch ]  [ Join in collection ]  [ Tell your friends ]  [ Print this article ]  [ Illegal reporting ]  [ close window ]

 

 
Recommend Tech
Click rank
cancel

Thank you for your support, I will continue to work hard.!

Sweep code support
Say as much as you like.

openAlipayIf you sweep, you can get a reward for sweeping yards.

Website Homepage

About Us

Contact

Use Agreement

Copyright privacy

Sitemap

Service Items

Member Service

Advertising Services

Website Message

Four Privileges

Payment Method

Apple APP Download
Android App Download
Mining Club
Contact Us

029-85212477

We are always waiting for your visit!

| ICP business license: Shaanxi ICP No. 15507745