Waste heat recovery and application analysis of domestic waste incinerator
In recent years, China's urban domestic waste has increased rapidly. Under this background, how to scientifically treat domestic waste and effectively reduce environmental pollution has become the foc
At the moment of advocating green and sustainable development, China pays more and more attention to domestic waste treatment. Under this situation, strengthening the recovery and application of waste heat of domestic waste incinerator can create the final value of domestic waste, supply energy for people's production and life while meeting people's waste treatment needs, and promote the recycling of waste treatment. Although more attention has been paid to the waste heat recovery and application of domestic waste incinerator in recent years, the equipment and technology involved in waste heat recovery and application of incinerator are still in the state of further research and development. In this case, analyzing the waste heat recovery and application of domestic waste incinerator, promoting the research and development of relevant technologies and equipment, and achieving the purpose of effective utilization of each resource has become a task that relevant professionals must pay attention to.
Analysis of mechanical grate incinerator
Mechanical grate incinerator is a widely used domestic waste incinerator. This type of incinerator can also be divided into rolling rotary grate, forward shaking grate and reverse shaking grate. First of all, when the rolling rotary grate is used to incinerate the domestic waste, it is necessary to put the waste in the appropriate position first, even if the waste is perpendicular to its flow direction in the grate, and then turn the waste in the overturned state with the help of the cylinder rotation force, so as to dehydrate, dry and burn the waste as soon as possible. In addition, effective turning can also improve the problem that the waste is not fully burned out to a certain extent. Secondly, when the forward shaking grate is used to incinerate the domestic waste, the waste needs to be placed on the grate first, and then the waste is stirred and turned over, so as to speed up the drying and combustion rate of the waste, so that the waste can fully contact with the air and burn out. After the waste is burned out, the remaining non combustible substances are discharged from the ash discharge system. Finally, when the reverse shaking inclined grate is used to incinerate the domestic waste, the moving direction of the movable grate is always opposite to the direction of waste flow, so that the waste is stirred and turned, which can not only realize rapid drying and combustion, but also create favorable conditions for the full combustion of waste.
From the above, it can be seen that the working characteristics of mechanical grate incinerator are as follows: when using this kind of incinerator to incinerate garbage, it can fully stir and turn the garbage, accelerate the dehydration, drying and combustion speed of garbage, and burn the garbage out. Comparing the above three types of mechanical grate incinerators, it can be found that different types of mechanical grate incinerators have their own advantages and disadvantages. The details are as follows: the first type of mechanical grate incinerator has low cost of domestic waste incineration, but when it is necessary to treat domestic waste with high water content and low calorific value, combustion supporting agent must be added to promote the effective combustion of domestic waste, The second kind and the third kind of mechanical grate incinerator have slightly higher domestic waste incineration cost, but the second kind of mechanical grate incinerator has obvious advantages in treating domestic waste with low water content but high calorific value. The third kind of mechanical grate incinerator has unique advantages in treating domestic waste with high water content but low calorific value.
Analysis on the key of waste heat recovery and application of domestic waste from the perspective of incinerator
Reduce ash deposition on heating surface
When recovering and utilizing the waste heat of domestic waste incinerator, the heating surface of waste heat boiler needs to be used to absorb heat and produce steam. In the process of heat absorption and steam generation on the heating surface, it is noteworthy that the composition of domestic waste is complex, and a large number of toxic and harmful flue gases will inevitably be produced in the combustion process. These flue gases are often highly corrosive and will cause serious harm to the heating surface. In addition, there are countless fine particles in the flue gas formed by burning domestic waste. These fine particles continue to accumulate on the heating surface and will gradually form a structure similar to the thermal insulation layer, which is extremely unfavorable to the heating surface for absorbing the waste heat of the incinerator. Therefore, in the recovery and application of waste heat from domestic waste incinerator, certain protective measures must be taken for the heating surface to prevent ash from forming blocks on the heating surface. In view of the above problems, the furnace can be expanded as much as possible when designing the furnace, and the way of repeated arrangement can be adopted when designing and arranging the radiant heating surface, so as to protect the heating surface, reduce the accumulation of smoke and dust on the surface area of the heating surface, and make the surface cleaning of the heating surface easier.
Avoid sulfide corrosion
Sulfide will be produced in the process of domestic waste incineration, which will also cause corrosion to the heating surface. However, combined with the sulfide reaction principle, the corrosion of sulfide on the heating surface is very slight under high temperature, and the heating surface will be subject to obvious corrosion only when sulfuric acid is formed under low temperature. Therefore, when recovering the waste heat of domestic waste incinerator, in order to avoid the corrosion of sulfide on the heating surface, the temperature needs to be effectively controlled to avoid too low temperature. Specific control measures include: when designing the incinerator, ensure that the temperature of the incinerator when treating domestic waste can exceed the dew point temperature of sulfide; In addition, the open circuit valve can be designed between the heating surfaces to ensure that the temperature is always above the sulfide dew point temperature.
Avoid chloride corrosion
A large number of harmful substances will be produced in the working process of domestic waste incinerator. The chloride in the harmful substances has strong corrosivity to the heating surface of waste heat boiler. Coupled with the high-temperature catalysis in the process of domestic waste incineration, the corrosivity of chloride will be further highlighted and cause irreversible damage to the heating surface. Therefore, in the recovery and application of waste heat from domestic waste incinerator, targeted measures must be taken based on the problem that chloride will seriously corrode the heating surface. When taking measures, it is first necessary to understand the influencing factors when chloride corrodes the heating surface. According to the relevant research data and practical experience, there are two main influencing factors, one is the temperature and the other is the material of the heating surface. Generally speaking, when the temperature is lower than 300 ℃, chloride has less corrosion on the heating surface; When the temperature reaches 300 ℃, chloride corrodes the heating surface seriously; When the temperature reaches 450 ℃, chloride can severely corrode the heating surface. When the heating surface is made of high-grade materials, it is less vulnerable to chloride corrosion, while when the heating surface is made of low-grade materials, it is more vulnerable to chloride corrosion. Therefore, in order to avoid chloride corrosion and protect the heating surface, we can control the temperature around the heating surface and optimize the materials of the heating surface to form effective protection for the heating surface.
Application of waste heat in domestic waste incinerator
The waste heat of domestic waste incinerator is often used for power generation and heating, such as converting it into electric energy as the domestic electricity of nearby residents, using the waste heat of incinerator for heating in winter and so on. In the process of practical application, in order to improve the utilization efficiency of waste heat and save the application cost, it is necessary to make scientific planning for the incineration plant. When planning, first, we need to pay attention to the utilization efficiency of waste heat of domestic waste incinerator. For example, there are cases in foreign countries where the incinerator is built near the amusement park and the normal operation of the amusement park is maintained by recycling and applying the waste heat of domestic waste incinerator. Because the incinerator is close to the amusement park, it can effectively reduce the loss in the process of energy transmission and improve the utilization efficiency of waste heat; The second is to ensure the harmlessness in the process of waste heat recovery and application of domestic waste incinerator, that is, while recovering and applying waste heat, we should effectively deal with the toxic and harmful substances produced in the process of domestic waste incineration, so as to avoid the harm of these substances to the environment and the health of nearby residents. In short, with a huge amount of domestic waste, the heat generated by domestic waste incineration is quite huge. Collecting these heat and making scientific use of them can reduce China's dependence on other energy, especially non renewable energy, and is of great significance to China's long-term development.
It can be seen from the above that in order to promote the effective recovery and application of waste heat from domestic waste incinerators, it is necessary to first understand the commonly used domestic waste incinerators in practice, grasp the key of waste heat recovery and application technology of incinerators, and pay attention to the planning and construction of incineration plants, so as to promote the improvement of the conversion rate of domestic waste resources. With the continuous increase of domestic waste in China, continuously promoting the research and development of waste heat recovery and application technology of domestic waste incinerator, transforming domestic waste into valuable resources and reducing the pollution caused by incineration of domestic waste can promote the improvement of waste treatment technology and provide a solid foundation for sustainable green development in China.