2 330,000 circulating fluidized bed boiler thermal power operation, inspection is good to change job

The scope of this problem is large, and it can only be explained simply: 1. The boiler is the main equipment of the thermal power plant, and the common boilers are pulverized coal furnace, circulating fluidized bed boiler, as well as chain furnace, coal throwing furnace and other types, steam temperature, steam pressure, and evaporation are the main parameters of the boiler. Through the combustion of coal, the water in the pot is heated, and superheated steam at a certain pressure and temperature is formed to propel the steam turbine to rotate.

The boiler itself is equipped with auxiliary machinery, which is mainly for coal, pulverization and ventilation. 2. The steam turbine is the second main equipment of the power plant, and the common steam turbines are condensing, condensing, and back pressure. The steam parameters of the steam turbine are matched with the boiler, and the power and speed are matched with the generator.

The steam turbine uses a valve to control the amount of steam intake, the steam impulse impeller rotates, and the speed control system can maintain a stable speed. The auxiliary equipment of the steam turbine is mainly the oil pump for lubricating the bearing, the oil cooler, the condenser, the condensate pump, etc. 3. The generator is the third main equipment of the power plant.

Generators have voltage, current, power, and other parameters. The generator is equipped with an excitation system, and generally with a coaxial exciter. The steam turbine drives the generator and the exciter to rotate, and the exciter supplies the generator rotor magnetic field, and the rotor magnetic field cuts the stator coil, and the generator forms an induced electric potential.

Once connected to the grid, active and reactive power can be transmitted to the grid. The outlet voltage of the generator is generally only 6--20kv, in order to transmit power over long distances, the outlet of the generator should be connected to the power grid through the step-up transformer, and the step-up transformer is called the main transformer. 4. Chemical water is the meaning of chemical water treatment, which is divided into different processes and processes.

Firstly, the raw water (circulating water) is extracted from the river, the domestic fire water is obtained by precipitation filtration, the industrial water is obtained by further dosing, and the demineralized water is obtained by chemical treatment. Demineralized water is the working fluid that is sent to the boiler to turn into steam. Okay, that's probably it, don't understand and ask again.

During the operation of the circulating fluidized bed boiler, the coal feed should be adjusted smoothly, and the principle of "small number and frequent adjustment should be achieved" should be achieved as far as possible to prevent coking or flameout caused by large changes in bed temperature. During operation, the coal feeding system should be checked frequently to see if it is operating normally, and if there is any abnormality, it should be dealt with in time. During operation, the coal volume and air volume are adjusted in time according to the load, bed temperature and coal quality change, so as to maintain the stability of bed temperature, steam temperature, steam pressure and load.

Controlling the amount of material circulating is what makes the operation of a circulating fluidized bed boiler different from that of a conventional boiler. According to the combustion and heat transfer characteristics of circulating fluidized bed boiler, the amount of material circulation plays a pivotal role in the operation of circulating fluidized bed boiler, because the temperature field in the furnace is evenly distributed in the upper part of the furnace in the bright state, and it is exchanged with the water wall through a variety of heat transfer methods, so it has a high heat transfer coefficient. By adjusting the amount of circulating material, the temperature of the material bed and the differential pressure of the furnace can be controlled, and the boiler load can be further adjusted.

The increase in the amount of material circulation can make the temperature distribution of the whole combustion chamber tend to be uniform, and can increase the residence time of the fuel in the furnace, thereby improving the combustion efficiency. The amount of circulating material is directly related to the separation efficiency of the boiler separator. The higher the separation efficiency of the separator, the greater the amount of return separated from the flue gas, so that the boiler can adjust the load to the greater the enrichment, which will be conducive to improving the boiler efficiency and calcium oxide utilization rate, reducing the Ca-S ratio and improving the desulfurization efficiency.

The development of circulating fluidized bed boiler is of special significance in China. Most of the fuel required for China's power and industrial and civil heating comes from coal. China has a vast territory and a wide variety of coal types, and in order to consume local low-quality coal and obtain lower pollution emissions at a smaller cost, circulating fluidized bed combustion technology is urgently needed.

The application and development of circulating fluidized bed boiler in China has comprehensive social benefits. Fluidized bed boilers are known for burning low-quality coal, which has a calorific value between 18,000 kJ kg --- 23,000 kJ kg. Knowing these, the coal consumption of a 15-ton boiler can be passed by the formula:

Boiler coal consumption = boiler power * 3600 coal combustion heat boiler efficiency to calculate. We know that the heat required for 1 ton of coal-fired boiler is 600,000 kcal hours, the fluidized bed boiler burns inferior coal, the calorific value of coal is about 4000kcal kg, and the boiler thermal hole efficiency is generally about 85%, so 1 ton of fluidized bed (fluidized bed boiler does not have 1 ton For example, just to say that it is easy to understand) The coal consumption per hour is: 600000kcal h 4000kcal kg 85%=.

Coal (limestone) is sent into the furnace for combustion, the material is brought into the upper part of the furnace by a wind for combustion, and the large particles (not fully combusted) fall into the lower part of the furnace along the inner wall of the furnace through their own gravity, and so on, which is called internal circulation. The fine particles are sucked and entrained by the flue gas into the cyclone separator, falling into the returner through centrifugal force and gravity, and being sent to the furnace through the return air and loose air. constitutes the outer circulation.

The fine ash is sucked into the dust removal grinder by the induced draft fan, and enters the flue after the dust removal is completed. First of all, the amount of coal consumption depends on the type of coal burned, and the effect achieved by burning different types of coal is also different, and the natural coal consumption is also different, so it is not blindly calculated according to the standard coal, which will have a big error. The coal consumption of a fluidized bed boiler can be calculated by a formula that is as follows:

Boiler coal consumption = boiler power 3600 coal combustion heat boiler efficiency. Each boiler is designed in a different amount.

1. Operation technology. 2. Device status. 3. Excellent coal quality. 4. The external gas consumption is unstable.

Burning inferior coal, desulfurization in the furnace, energy saving and environmental protection.

Circulating fluidized bed boiler is the most industrialized clean coal combustion technology. The circulating fluidized bed boiler adopts fluidized combustion, and the main structure includes two parts: combustion chamber (including dense phase zone and dilute phase zone) and circulating return furnace (including high-temperature gas-solid separator and return system). The biggest difference with bubbling fluidized bed combustion technology is that the operating wind speed is high, which strengthens the heterogeneous reaction process such as combustion and desulfurization, and the boiler capacity can be expanded to a large capacity (600MW or above) acceptable to the power industry.

For a bed composed of particles of uniform particle size, when the gas flow rate through the fixed bed is very low, with the increase of wind speed, the bed pressure drop increases proportionally, and when the wind speed reaches a certain value, the bed pressure drop reaches the maximum, which is slightly greater than the bed static pressure, if the wind speed continues to increase, the fixed bed will suddenly unlock, and the bed pressure drop will drop to the bed static pressure. If the bed is composed of wide sieving particles, its characteristics are: before the large particles move, the small particles in the bed have been partially fluidized, and the unlocking phenomenon of the bed from fixed bed to fluidized bed is not obvious, but often the phenomenon of stratified fluidization occurs.

The minimum velocity required for a particle bed to transition from a stationary state to fluidization is called the critical fluidization velocity. As the wind speed increases further, the bed pressure drop is almost constant. The general fluidized wind speed of circulating fluidized bed boiler is 2 3 times the critical fluidization velocity.

Factors influencing the critical fluidization velocity:

The thickness of the material layer has little effect on the critical flow velocity.

The increase of the equivalent average diameter of the material layer increases the critical flow velocity.

The critical flow velocity increases as the density of solid particles increases.

Circulating fluidized bed combustion technology is one of the most commercialized clean coal combustion technologies, which has been rapidly developed in the past 20 years and has begun to be widely used in industrial boilers, power plant boilers and waste incineration. China's research and development of this technology started late, but the progress is very fast, and the circulating fluidized bed boiler with a capacity of 220t h and below has been promoted in a large area of industry in China and has been commercialized; The 480t h circulating fluidized bed boiler has been put into commercial operation. Demonstration projects for 200MWE and 300MWE circulating fluidized bed boilers are also being actively planned.

This book is written by the front-line technicians who have been engaged in the theoretical research, technology development, product design, operation and debugging of circulating fluidized bed combustion technology for many years. This book is a monograph on the principle, operation and maintenance of circulating fluidized bed boilers. This paper summarizes the basic theory of circulating fluidized bed combustion technology, corrects some popular wrong concepts, and introduces the typical structure, characteristics, installation requirements, operation technology, commissioning experience, performance test methods, key points of overhaul and maintenance, and handling of operation accidents of circulating fluidized bed boilers.

This book has both basic theories and practical experience, which is simple to understand, relatively close to reality, and easy to understand. This book is suitable for professional and technical personnel and management personnel engaged in the design, manufacture, operation, installation, commissioning, maintenance and design of circulating fluidized bed boilers, as well as scientific researchers and power engineering students who are engaged in the basic theory research of circulating fluidized bed boilers. The excess air coefficient is the ratio of the air quality actually supplied by burning 1kg of fuel to the air quality required to completely burn 1kg of fuel in theory.

Excess Air Coefficient = Actual Air Quality Supplied by Burning 1kg of Fuel Theoretical Air Quality Required to Completely Burn 1kg of Fuel.

If the oxygen content is too high, the exhaust heat loss is too large, and the oxygen content is too low, it cannot be completely combusted, which causes excessive costs and affects the efficiency of the plant. In relation to desulfurization, high oxygen content increases sulphur dioxide.

In order to maintain good combustion, attention should be paid to controlling the excess air coefficient of the furnace to ensure a suitable air-to-coal ratio in combustion. During operation, the excess air coefficient at the furnace outlet is controlled by measuring the amount of oxygen at the tail flue outlet. At the rated output, the corresponding oxygen value is approximately controlled at the volume ratio, which is based on dry flue gas).