In the integrated oil combustion process, the generation of nitrogen oxides (NOx) mainly comes from thermal NOx, fuel NOx and rapid NOx. Thermal NOx is generated by the reaction of nitrogen and oxygen in the air at high temperature. When the combustion temperature exceeds 1500℃, its generation increases exponentially with the increase of temperature; fuel NOx comes from the oxidative decomposition of nitrogen-containing compounds in the fuel; rapid NOx is generated by the reaction of hydrocarbon free radicals and nitrogen under rich combustion conditions. A deep understanding of these generation mechanisms is the premise for the targeted implementation of low-nitrogen emission control technology.
Staged combustion technology is a basic means to reduce nitrogen oxide emissions. It sends the air required for combustion into the integrated oil burner in stages. The primary air first burns with the fuel in an oxygen-poor combustion to reduce the peak combustion temperature; the secondary air is supplemented in the later stage of combustion to ensure complete combustion of the fuel. In this way, the generation of thermal NOx is reduced. At the same time, staged combustion can also change the oxygen concentration distribution in the combustion area and inhibit the generation of fuel NOx. For example, the design of two layers of air channels inside and outside is adopted. A small amount of air is introduced into the inner layer to form a rich combustion zone, and the outer layer is supplemented with air to achieve complete combustion, which can effectively reduce NOx emissions by 30% - 50%.
The flue gas recirculation technology reduces the generation of NOx by introducing part of the flue gas after combustion into the combustion zone, diluting the oxygen concentration and reducing the combustion temperature. The mixing of low-temperature flue gas reduces the peak flame temperature and weakens the generation conditions of thermal NOx. In practical applications, optimizing the flue gas recirculation rate is the key. Too high a recirculation rate may lead to unstable combustion, which is generally controlled between 10% - 25%. At the same time, an advanced flue gas mixing device is used to ensure that the flue gas is evenly mixed with air and fuel, further improving the low nitrogen emission effect.
The structural innovation of the low-nitrogen integrated oil burner is the core of achieving emission control. Improve the nozzle design of the integrated oil burner, adopt a swirl blade or venturi tube structure, enhance the mixing effect of fuel and air, make the combustion more uniform and slow, and avoid local high temperature. A special flame stabilizer is designed to control the flame shape and length and reduce the residence time in the high temperature area. In addition, the premixed combustion technology is used to fully mix the fuel and air before combustion to achieve lean combustion and suppress NOx generation from the root. Some advanced low-nitrogen integrated oil burners can reduce NOx emissions to below 30mg/m³.
Selective catalytic reduction technology is an effective means to deeply reduce NOx emissions. An SCR reactor is installed in the tail flue of the integrated oil burner, and ammonia or urea solution is used as a reducing agent. Under the action of the catalyst, NOx is reduced to nitrogen and water. The commonly used catalyst is a vanadium-titanium catalyst, which has a high catalytic activity in the temperature range of 250℃ - 450℃. By accurately controlling the injection amount of the reducing agent and the reaction temperature, the NOx removal rate can reach 80% - 90%, meeting the strict environmental emission standards.
Build an intelligent monitoring system to monitor the operating parameters of the integrated oil burner in real time, such as temperature, pressure, oxygen content and NOx emission concentration. The combustion process is optimized and controlled by using big data analysis and artificial intelligence algorithms. When NOx emissions exceed the standard, the system automatically adjusts the air-fuel ratio, flue gas recirculation rate and other parameters of the integrated oil burner to ensure that the combustion process is always in a low nitrogen emission state. At the same time, through the predictive maintenance function, abnormal wear or failure of the integrated oil burner components can be discovered in time to avoid increased NOx emissions due to equipment problems.
Implement environmental protection management of the integrated oil burner throughout its life cycle, from equipment selection, installation and commissioning to operation and maintenance and decommissioning, and implement environmental protection concepts throughout the entire process. In the selection stage, integrated oil burner products with low nitrogen emissions are preferred; during installation and commissioning, operations are strictly carried out in accordance with standards to ensure that equipment performance meets standards; during operation, a complete environmental management system is established, and emission testing and equipment maintenance are carried out regularly; after the equipment is retired, it is harmlessly treated, and usable resources are recovered to reduce the impact on the environment, so as to achieve all-round environmental protection control from source to end.
