We use cookies to improve your online experience. By continuing browsing this website, we assume you agree our use of cookies.

Detailed Explanation Of The Principle Of Garbage Incinerator

Views : 139
Update time : 2024-01-11 11:27:00
The garbage incinerator is a kind of environmental protection equipment that incinerates waste gas, waste liquid, solid waste fuel, medical waste, domestic waste, animal carcasses, etc. at high temperature to reduce or shrink the quantified number. At the same time, it can utilize the heat energy of part of the incineration medium. of a product.
The calorific value, composition and dimensions of domestic waste are the main factors affecting the incineration of domestic waste. The higher the calorific value, the easier the combustion process is and the better the incineration effect will be. The smaller the size of the domestic waste components, the better the unit mass or volume of domestic waste, and the more complete the combustion; on the contrary, the mass transfer and heat transfer effects are poor, and incomplete combustion is prone to occur.
Nature of domestic waste
The calorific value, composition and dimensions of domestic waste are the main factors affecting the incineration of domestic waste. The higher the calorific value, the easier the combustion process is and the better the incineration effect will be. The smaller the size of the domestic waste components, the better the unit mass or volume of domestic waste, and the more complete the combustion; on the contrary, the mass transfer and heat transfer effects are poor, and incomplete combustion is prone to occur. The waste entering the factory stays in the storage pit for a certain period of time. Through natural compression and partial fermentation, the calorific value of the waste entering the furnace is increased and the incineration effect of the waste is improved. It is also the key to the quality of waste incineration. Proper storage allows garbage to fully ferment and dry.
Domestic waste entering the factory is not sent directly to the waste incinerator, but must go through the storage process. Setting up garbage storage pits is, firstly, to store the garbage entering the factory, which plays a role in regulating the quantity of garbage; secondly, it is used to stir, mix, dehydrate and other treatments for the garbage, which plays a role in regulating the nature of the garbage. In addition, the waste entering the factory stays in the storage pit for a certain period of time. Through natural compression and partial fermentation, the moisture content of the waste can be reduced, thereby increasing the calorific value of the waste entering the furnace and improving the incineration effect of the waste. The residence time of domestic waste in the storage pit is 3 to 5 days, which is more suitable. If the temperature is low and the humidity is high, the residence time can be extended appropriately.
residence time
Residence time has two meanings: one is the residence time of domestic waste in the incinerator, which refers to the time required for the slag to be discharged from the furnace from the beginning of entering the furnace to the end of incineration; the second is the flue gas of domestic waste incineration The residence time in the furnace refers to the time required for the flue gas generated by the incineration of domestic waste to escape from the domestic waste to be discharged from the secondary combustion chamber.
During actual operation, the residence time of domestic waste in the furnace must be greater than the theoretical total time required for drying, thermal decomposition and combustion. At the same time, the residence time of the incineration flue gas in the furnace should ensure that the gaseous combustibles in the flue gas achieve complete combustion. When other conditions remain unchanged, the longer the residence time, the better the incineration effect. However, too long a residence time will reduce the processing capacity of the incinerator, and too short a residence time will cause incomplete combustion of garbage. Therefore, the length of stay should be determined by the specific circumstances. Reasonably adjust the residence time of garbage in the furnace. Different types of garbage have different residence times in the furnace. The stoker must reasonably adjust the residence time according to the dryness, type and incineration effect of the garbage to achieve stable combustion and complete incineration of the garbage.
After the garbage enters the boiler, it is first dried on the first-level grate using the heat of the furnace, then burned on the second and third-level grates, and finally burned on the fourth-level grate. The residence time of the grates at all levels is too long and affects the amount of garbage processed. If the residence time is too short, it affects the effect of garbage incineration. After summarizing more than a year of production experience, the author has concluded that in order to allow the garbage to be fully dried in the furnace, the residence time of the garbage on the first-level grate should be between 100 and 110 seconds. For full combustion in the furnace, the residence time of the second and third level grates should generally be between 80 and 100 seconds. In order to completely burn the garbage, the residence time of the fourth level grate should be between 180 and 200 seconds. suitable.
In addition, with the change of seasons, the moisture content, dryness and type of garbage, the reciprocating residence time of the grate must be adjusted. Usually in the rainy season and when the temperature is low, the residence time of the grate needs to be appropriately increased. In short, only by reasonably adjusting the residence time of garbage in the furnace can the garbage be burned stably.
temperature
Due to the large size of the incinerator, the temperature distribution in the furnace is uneven, that is, the temperatures in different parts of the furnace are different. The incineration temperature mentioned here refers to the highest temperature that can be achieved by garbage incineration in a combustion chamber (combustion zone). Generally speaking, the temperature in the area above the garbage layer in the combustion section and close to the combustion flame is the highest, which can reach 850~1100℃. . The higher the calorific value of domestic waste and the higher the incineration temperature that can be achieved, the more conducive it is to the incineration of domestic waste. At the same time, temperature and residence time are a pair of related factors. Appropriately shortening the residence time at higher temperatures can also maintain better incineration effects.
Keep the furnace temperature stable and increase the primary air temperature as much as possible
The primary air required for waste incineration enters the boiler after passing through the steam air heater and flue gas air heater. Because the higher the temperature of the primary air, the faster the garbage dries and the better it burns. Therefore, it is necessary to keep the temperature of the primary air stable. In addition, the furnace temperature and the temperature of the primary air affect each other. The higher the furnace temperature, the better the garbage incineration effect, and the higher the primary temperature. Only when the temperature of the furnace is stable can the stable combustion of garbage and the stable operation of the boiler be ensured, stable steam and flue gas be generated, and the normal operation of the air preheater be ensured, thereby ensuring the temperature of the primary air is stable. When the temperature of the furnace is low, oil must be added in time to support combustion. , to ensure that the temperature of the furnace is stable, a virtuous cycle can be established and the stable combustion of garbage can be ensured.
Turbulence
Turbulence degree is an indicator of the mixing degree of domestic waste and air. The greater the degree of turbulence, the better the mixing degree of domestic waste and air. Organic combustibles can fully obtain the oxygen required for combustion in a timely manner, and the combustion reaction is more complete. Turbulence is affected by many factors. When the incineration reaches a certain level, increasing the air supply can increase the turbulence and improve the mass and heat transfer effects, which is beneficial to incineration.
Excess air coefficient
According to the combustible composition and stoichiometric equation, the amount of air equivalent to the amount of oxygen required to burn unit mass of garbage is called the theoretical air amount. In order to ensure complete combustion of garbage, it is usually necessary to supply more air volume than the theoretical air volume, that is, the actual air volume. The ratio of the actual air volume to the theoretical air volume is the excess air coefficient, also known as the excess air rate or air ratio. The excess air coefficient has a great influence on the combustion conditions of garbage. The supply of appropriate excess air is a necessary condition for the complete combustion of organic matter. Increasing the excess air coefficient can not only provide excess oxygen, but also increase the turbulence in the furnace, which is beneficial to incineration. However, an excessive excess air coefficient may lower the temperature in the furnace, causing side effects to incineration, and will also increase the energy required for air transportation and preheating. If the actual air volume is too low, the waste will be burned incompletely, which will in turn bring a series of adverse consequences to the incineration.
Reasonable air distribution and selection of appropriate excess air coefficient
The air required for incineration in the garbage incinerator is supplied by primary air and secondary air. The primary air is arranged on the same side below the grate and is controlled by a total of eight electric dampers. The secondary air is arranged in the furnace and the front and rear arches directly above it. There are a total of twelve nozzles on the water-cooled wall, each controlled by four electric dampers. Through aerodynamic field testing and summarizing the previous incineration experience, the ratio of primary air to secondary air should be 6:4, which is more appropriate. This can ensure the garbage incineration effect and the full combustion and decomposition of combustibles in the flue gas. At the same time, the primary air distribution The principle of large in the middle and small at both ends should be met, that is, the opening of the middle damper should be increased, and the opening of the dampers at both ends should be adjusted small, because the second and third-level furnace grates are the main combustion area, and the fourth-level grate is the burnout area. Only in this way can the air required for combustion in the furnace of the garbage furnace be met. In addition, reasonable air distribution can also be carried out according to the oxygen content of the boiler horizontal flue gas. Generally, the oxygen content of the flue gas in the horizontal flue should be controlled between 10 and 12%. Therefore, only reasonable air distribution can ensure the stability of the garbage. combustion. To maintain a stable negative pressure in the furnace, the negative pressure in the garbage incinerator furnace should be controlled between -20 and -50Pa. If the negative pressure in the furnace is too small, the furnace will easily spray dust outwards, which not only affects environmental sanitation, but may also endanger the safety of equipment and operators; and if the negative pressure is too small, the amount of air leakage in the furnace will increase, increasing the power consumption and smoke of the induced draft fan. Gas heat loss. Therefore, stabilizing the furnace negative pressure is of great significance to ensure stable combustion of the boiler.
Reasonably adjust the residence time of the feeder and select the appropriate stroke
Garbage enters the boiler through the reciprocating movement of the feeder. Therefore, the movement time and mode of the feeder directly affect the amount of garbage entering the furnace. Selecting the appropriate residence time of the feeder can ensure uniform feeding. According to experience, the residence time of the feeder is about 400s. However, it should be adjusted according to different types of garbage. It is also very important to flexibly choose the appropriate stroke. If the stroke is too large, too much garbage will enter the furnace at one time, causing large fluctuations in furnace temperature and affecting the incineration effect; if the stroke is too small, it will cause Material is unavailable or insufficient. According to experience, the feeder stroke is about 500mm.
Reasonably adjust the thickness of the material layer
The thickness of different garbage in the furnace is also inconsistent. The stove must reasonably adjust the thickness of the material layer according to the incineration effect of the garbage in the furnace to ensure stable combustion of the garbage. If the thickness is too large, it may lead to incomplete combustion and unstable combustion. If the thickness is too thin, the processing capacity of the incinerator will be reduced. The author believes that the thickness of the first-level grate layer is between 0.8 and 1 meter, the thickness of the second and third-level grate layers is between 0.6 and 0.8 meters, and the thickness of the fourth-level grate layer is between 0.8 and 1 meter. Between 0.2 and 0.4 meters is more suitable. However, the thickness of the garbage layer of different grate structures is also different, which must be determined according to different types of grates.
in conclusion
1. Waste incineration and power generation can achieve the purpose of harmlessness, volume reduction and resource utilization of waste treatment. It should be actively promoted in China to change the current single landfill treatment method and achieve the sustainable development of domestic waste treatment.
2. For the incineration of domestic waste with low calorific value, high moisture, complex composition and which has not been sorted, government departments should take corresponding encouraging measures to ensure the healthy development of the domestic waste incineration power generation industry.
3. The application of waste incineration technology has just begun in our country. In the promotion of waste incineration technology, we should make full use of foreign advanced technology and domestic existing technology to achieve advanced technology and reasonable investment.
In summary, during the incineration process of domestic waste, various related influencing factors should be reasonably controlled where possible, so that the comprehensive effect develops in a direction conducive to the complete combustion of domestic waste. But at the same time, it should be recognized that these influencing factors are not isolated. They are interdependent and mutually restrictive. The positive effect of one factor may lead to the negative effect of another factor, so it should be viewed from the perspective of comprehensive effect. question.
Related News
Read More >>
Hematology Doctor - Blood Cell Analyzer Hematology Doctor - Blood Cell Analyzer
Dec .31.2024
A blood cell analyzer refers to a conventional testing instrument that automatically analyzes the heterogeneity of blood cells within a certain volume of whole blood. It usually consists of a blood cell detection module, a hemoglobin determination module, a mechanical module, an electronic module, a computer system, etc. The principles are generally electrical impedance method, colorimetry, flow laser scattering technology, etc.
What should you pay attention to when setting up an operating room? What should you pay attention to when setting up an operating room?
Dec .29.2024
Setting up an operating room requires meticulous attention to detail to ensure a safe, sterile, and efficient environment for surgical procedures. Here are key considerations when setting up an operating room:
Operating procedures for common laboratory instruments and equipment Operating procedures for common laboratory instruments and equipment
Dec .27.2024
Precision and meticulousness are crucial in operating laboratory instruments. Following proper procedures not only ensures accurate results but also prolongs the lifespan of the equipment. Regular maintenance, calibration, and adherence to operating guidelines are fundamental to achieving reliable and consistent outcomes in laboratory analyses.
Operating points and daily maintenance of commonly used pathological equipment Operating points and daily maintenance of commonly used pathological equipment
Dec .25.2024
Regular maintenance and adherence to proper operating procedures are paramount to ensure the accuracy and reliability of pathology equipment. Compliance with manufacturer guidelines, routine inspections, and a proactive maintenance schedule contribute significantly to the longevity and efficacy of these crucial diagnostic tools.