Low NOx incinerator and low NOx incinerator refer to the incinerator with low NOx emission in the fuel incineration process. The adoption of low NOx incinerator can probably reduce the NOx emission in the incineration process.
No and NO2 are the most important oxides of nitrogen in the incineration process, which are generally called NOx. According to the results of a large number of tests, no is the most important nitrogen oxide discharged by incineration assembly, accounting for 95% on average, while NO2 only accounts for 5% of the total.
No produced by general fuel incineration mainly comes from two aspects: one is the oxidation of nitrogen in the combustion atmosphere (combustion supporting atmosphere); the other is the thermal decomposition and reoxidation of nitrogen compounds in the combustion process. In numerous incineration assemblies, the former is the key source of No. we call such no "thermal feedback no", the latter "fuel no", and the other "instantaneous no".
The NO produced during incineration can be approximately recovered to NO2 by feedback with the products of the nitrogen atom center. In fact, in addition to these feedbacks, no can also produce NO2 with various nitrogen-containing compounds. In the actual incineration assembly, when the feedback reaches the chemical average, the proportion of [NO2] / [no] is very small, that is, the change of no to NO2 is very little, which can be roughly generalized.
Incineration technology of low NOx
NOx is generated by incineration, and the incineration techniques and premise have a great impact on the production of NOx. The main way to reduce NOx is to be able to experience the improvement of incineration technology, as follows:
The fuel with lower N content is selected, including denitrification of fuel and conversion to low nitrogen fuel;
The excess coefficient of low atmosphere and the structure of over dense incineration can reduce the oxygen concentration around the fuel;
In the environment of less excess atmosphere, the peak temperature is lowered to reduce the "thermal feedback no";
Under the condition of low oxygen concentration, the time for the combustibles to stop in the front peak and feedback zone of the flame is increased.
The detailed techniques of NOx reduction and emission are classified incineration, re incineration, low oxygen incineration, error incineration and flue gas recycling.
Brief introduction of low nitrogen oxide incinerator for general use
The incinerator is a tense building of industrial furnace, which guarantees the process of fuel consolidation, burning and thorough burning. Therefore, to control the production of NOx, it is necessary to start from the incinerator. For the incineration technology of low NOx, the low NOx incinerator can be divided into the following categories:
1. Stage incinerator
In the stage incinerator of the principle plan of left classification incineration, the fuel and atmosphere are burned in sections. Because the incineration deviates from the surface equivalent ratio, the production of NOx can be reduced.
2. I will recycle the incinerator
One is to use the pressure head of combustion supporting atmosphere to suck back the one-sided combustion flue gas into the incinerator and burn it with the atmosphere. Because the flue gas is recycled, the heat capacity of the incineration flue gas is large, the incineration temperature is low, and NOx is reduced.
Another kind of self recycling incinerator is to simply recycle one-sided flue gas in the incinerator, and then come into the incineration process. This kind of incinerator has dual consequences of nitrogen oxide suppression and energy saving.
3. Dense lean incinerator
The reason is that one side of the fuel is burned too intensively and the other is burned too thinly, but the atmosphere is fixed as a whole. Because both sides are burned with deviation from the chemical equivalent ratio, NOx is very low. This kind of incineration is also called deviation incineration or non chemical equivalent incineration.
4. Disc flame type incinerator
The principle is to divide a flame into several small flames, because the small flame has large heat dissipation area and low flame temperature, which makes the "thermal feedback no" drop. In addition, the flame slightly shrinks the pause time of oxygen, nitrogen and other gases in the flame, which has an obvious inhibitory effect on "thermal feedback no" and "fuel no".
5. Mixed excited incinerator
The pause time of flue gas in the high temperature area is one of the important components affecting the NOx production. Improving the mixture of incineration and atmosphere can roughly reduce the thickness of the flame surface. In the environment with fixed incineration load, the pause time of flue gas in the flame surface, i.e. the high temperature area, shrinks, thus reducing the NOx production. Mixed with the excited incinerator is to prove this truth plan.
6. Low NOx precombustion chamber incinerator
The precombustion chamber is a high compliance and low NOx staged combustion technology developed and researched in China in the past 10 years. The precombustion chamber is generally composed of primary air (or secondary air) and fuel radiation system. The fuel and primary air are mixed rapidly, resulting in fuel rich inclusions in the primary combustion area of the precombustion chamber. Because of lack of oxygen, only one-sided fuel is burned, and the fuel is in the one with low oxygen and flame temperature In order to reduce the production of NOx, volatiles are separated out in the sub flame area.
——Author：ebico