Accidents and analysis of economizers in circulating fluidized bed boilers

The influencing factors of the desulfurization efficiency of circulating fluidized bed boiler are (dry desulfurization in the furnace).

1. The purity of limestone, the activity of limestone, and the granularity of limestone;

2. The temperature of the bed. The reaction with the s in the coal is actually the calcium oxide decomposed by the limestone at 800-850, if the bed temperature is not enough, the limestone does not decompose, and the desulfurization efficiency is of course low.

3. The level of coal sulfur. Coal has a high sulfur content and low relative efficiency.

Generally: wear, omission, deterioration of the separator effect, coking blockage, etc., I don't know what kind of problem you encounter!

1. Limestone lime-gypsum desulfurization process.

1.The principle of the working friend potato.

Limestone lime-gypsum flue gas desulfurization uses limestone or lime as the desulfurization absorber, limestone is crushed and ground into powder and mixed with water to form an absorption slurry, when lime is used as an absorbent, lime powder.

After digestion, water is added to make the spine into an absorbent slurry. In the absorption tower, the absorption slurry is mixed with the flue gas, and the sulfur dioxide in the flue gas.

with calcium carbonate in the slurry.

and the oxidized air that is blown in to carry out a chemical reaction and be removed, and the final reaction product is gypsum.

2.System composition.

The desulfurization system is mainly composed of flue gas system, absorption and oxidation system, limestone lime slurry preparation system, by-product treatment system, wastewater treatment system, public system (process water, compressed air, accident slurry tank system, etc.), electrical control system and other parts.

3.Process characteristics.

1) High desulfurization efficiency, which can guarantee more than 95%;

2) The most widely used, mature technology, good operation reliability;

Measures to reduce the power consumption per ton of steam for 75 tons of circulating fluidized bed boiler:

1. Large motor realizes frequency conversion control; Such as induced draft fan motors, blowers, water pumps, etc.

2. Adjust the reasonable proportion of wind coal and check the gas leakage point.

3. The drum slag cooler is used for slag discharge, and the temperature of the hot material put down is used to heat the demineralized waterIn addition, the 75-ton circulating fluidized bed boiler also has the following advantages:

1. Wide applicability of boiler fuel: combustible anthracite, bituminous coal, inferior coal, industrial cinder, coal grinding stone, etc.;

2. The boiler has high combustion efficiency: the fuel ember rate is above 98, the separation effect is good, and the fly ash loss is less;

3. High efficiency desulfurization, low nitrogen oxide emissions, good environmental protection effect: the desulfurization rate is greater than 90, and the smoke and dust emission concentration is low;

Resources.

Adjust the reasonable proportion of wind coal, check the leakage point, and use the inverter control cabinet as mentioned downstairs.

If conditions permit, the drum slag cooler is used to heat the demineralized water by using the temperature of the hot material that is put down.

Large motor to achieve frequency conversion control;

Such as induced draft fan motors, blowers, water pumps, etc.

1.After the coal is broken, the oxygen content increases first, the bed temperature decreases rapidly, and the returner cools down at the same time, at this time, the secondary air should be stopped, and the primary air volume should be reduced at the same time.

2.Transformation, the returner is the same as the hearth, it is also a small fluidized bed, which can control its own fluidized air volume, and install a regulating door at the entrance to control the air volume. In addition, if the coal is not good, a vibrating motor can be installed at the coal mouth of the coal bunker.

3.When the operation is adjusted, the coal supply air should be increased appropriately.

4.If the coal quality is not good, you can adjust the particle size of the coal appropriately, not too fine, which requires controlling the crushing fineness of the crusher; If the coal is too wet, you can add some sand and gravel to the coal to facilitate the frictional flow of coal in the coal inlet pipe.

5.If it is an incinerator, you can use a garbage crane to mechanically add coal to the furnace, and at the same time immediately deal with the coal outage.

6.The last trick is to press the fire, which is a normal operation, while fire extinguishing is an operation error, and the performance bonus must be assessed, haha!

Your return system does not have a roots blower, causing the return air to change with the change of primary wind. And in this case, it should be that your return damper should be fully open. After the coal is broken, the pressure in the furnace decreases, the pressure in the air chamber decreases, the primary air volume becomes larger, the inlet air volume of the separator increases, the inlet speed increases, the efficiency of the separator increases, the pressure of the material leg increases, the return material increases under the effect of self-balancing, and the increase in the amount of return material causes the air chamber pressure to increase, and the return air pressure increases, so that the vicious circle and a large number of return materials.

A large amount of reproduced material will inevitably cause a drop in bed temperature and even fire extinguishing.

1. Composition of circulating fluidized bed boiler:

The circulating Youcha fluidized bed boiler is composed of the boiler body and auxiliary equipment

1. Boiler body: mainly including starting burner, air chamber, air distribution device, furnace, gas-solid separator, material return device, as well as steam drum, descending pipe, water wall, superheater, economizer, air preheater, etc.

2. Auxiliary equipment: mainly including blower, induced draft fan, return fan, crusher, coal feeder, cold slag device, dust collector, desulfurization and denitrification equipment, chimney, etc.

2. Structural characteristics of circulating fluidized bed pot state sales furnace:

The most important structural feature of the fluidized bed boiler is the material circulation system, which is composed of air distribution device, combustion chamber, gas-solid separator, material return device, ignition device and other equipment.

The combustion chamber, separator and material return device are known as the three core components of the circulating fluidized bed boiler, and constitute the particle circulation circuit of the circulating fluidized bed boiler, which is the obvious feature of its structure that distinguishes it from other boilers, and is the unique system of the circulating fluidized bed boiler.

3. The working principle of circulating fluidized bed boiler.

After the fuel is crushed to a suitable particle size by the crusher, it is fed from the upper part of the air distribution plate of the combustion chamber by the coal feeder, mixed with the hot boiling material of the combustion chamber, and is rapidly heated, and the fuel is quickly ignited and burned, under the action of higher air velocity, it fills the furnace, and a large number of solid particles are carried out of the combustion chamber, and after being separated by the gas-solid separator, the separated material returns to the furnace through the material return device to continue to participate in the combustion. The high-temperature flue gas exported by the separator is discharged from the chimney through the dust collector after the heat exchange between the tail flue and the convection heating surface.

The coal, wind, and smoke systems mentioned above are called boiler combustion systems, which are generally referred to as "furnaces".

On the other hand, the boiler feed water is sent to the economizer for preheating by the water pump, and then enters the steam drum, and then enters the descending pipe, the water wall is heated and evaporated and then returns to the steam drum, and the steam enters the superheater after the steam and water are separated and heated, and then sent to the user through the main steam pipeline.

Boiler operation. Boiler Operation" is a book published by China Electric Power Press in 2006. [1]

Title. Boiler operation.

Author. Yu Linjiao.

Publishing house. China Electric Power Press.

Publication date. 1 April 2006.

Pages. 424 pages.

Fast. Navigation.

Directory. Introduction.

In the past 10 years, a large number of 6 1OOMW thermal power generating units of local power plants, enterprise-owned power plants and thermal power plants have been put into operation one after another, and the number of new employees and production personnel in operation positions has increased rapidly. In order to do a good job in the post technical training and skill appraisal of operation and production personnel, in accordance with the requirements of the Ministry of the Ministry of "National Occupational Skill Appraisal Specifications for the Electric Power Industry", "Technical Grade Standards for Electric Power Workers" and "Specifications for the Operation of Thermal Power Plants" and operation regulations, highlight the key points of the post, pay attention to operational skills, and facilitate assessment and training, etc., the experts were organized to comprehensively revise the content of the first edition published in 1995 and published the "Training Materials for the Operation of Local Power Plant Posts" (the second edition), which is divided into boiler operation, 5 volumes of steam turbine operation, electrical operation, thermal control and operation, and power plant chemistry.

Directory. Preface.

Part 1: General Basic Knowledge.

Chapter 1: Fundamentals of Boiler Profession.

Section 1: Basic Knowledge of Fluid Mechanics.

Section 2: Basic knowledge of thermodynamics.

Section 3: Basic Concepts of Heat Transfer.

Section 4: Thermal Measuring Instruments and Automatic Adjustment.

Chapter 2: Introduction to Boilers for Small and Medium-sized Power Stations.

Section 1: Boiler composition and working process.

Section 2: Typical Combustion Patterns.

Section 3: Boiler Classification and Model.

Chapter 3: Fuel.

Section 1: Overview.

Section 2: Coal Composition and Its Properties.

Section 3: Main Characteristics of Coal.

Error correcting. Resources.

1. The gas content of the outlet of the water-cooled wall pipe with strong heating becomes larger, which may lead to the deterioration of boiling heat transfer, which may cause the water-cooled wall pipe to over-temperature burst, and the creep will accelerate under the action of high temperature, reducing the service life of the water-cooled wall.

2. The flue gas temperature at the outlet of the furnace is high during overload operation, the temperature of the outer wall of the superheater is high, the temperature difference between the inner and outer walls increases, and the stress increases. Under the action of high temperature and stress, the creep of the pipe accelerates, resulting in frequent bursts or reduced service life of the superheater.

3. The total air volume of overload operation increases, the flue gas velocity accelerates, and the wear of the heating surface intensifies. The primary air volume is large, the fly ash concentration is large, and the heating surface is worn large. The primary air volume is small, the combustion chamber temperature is high, and the risk of coking increases.

4. Overload operation, if the total air volume is small, (in fact, as long as the overload operation is carried out, regardless of the total air volume, the carbon content of fly ash and slag will increase), the carbon content of fly ash increases, which may cause coking in the separator and recycler. The slag has a high carbon content, which may cause coking in the slag cooler. The loss of incomplete combustion of boiler machinery increases.

particle size and medium of the coal entering the furnace; Adjustment of the ratio of primary and secondary winds; Reasonable internal and external circulation and differential pressure of the material layer; the cleanliness of the heating surface; feed water temperature, etc.