If you have some problems in the process of using biomass boilers in peacetime, you must solve them in time. If these problems are not answered for a long time, you should have a lot of influence on everyone’s work, so I hope everyone will not ignore them. It is. How should we go for desulfurization and denitrification of biomass boilers?
1. Does the biomass boiler need desulfurization and off-selling?
The characteristics of the biomass boiler flue gas. After investigation, testing and analysis of the biomass boiler flue gas, the biomass boiler flue gas has the following characteristics:
2. Technical scheme for desulfurization and denitrification for biomass boilers
Low nitrogen combustion technology
Low-nitrogen combustion technology belongs to control combustion technology. By adjusting the oxygen content in the combustion air and reducing the production of nitrogen oxides, all low-nitrogen combustion technologies must enable the boiler to have a stable combustion process, otherwise the transformation effect will not be obvious or the combustion will not occur. Stable problem. For biomass boilers, common flue gas recycling technology.
There are two processes for flue gas recycling technology:
Flue gas recirculation technology will also increase the concentration of sulfur dioxide pollutants in the flue gas and increase the water content, but reduce the total amount of flue gas emissions. The process flow of flue gas recycling technology is shown in Figure 1. Scheme 1 Scheme 2 Figure 1 Flue Gas Recycling Technology Process
SNCR is a selective non-catalytic reduction technology. SNCR technology is suitable for boilers with a flue gas outlet temperature of 800?1100 °C. Below this temperature, the denitration efficiency is low, and the mixing effect of ammonia and flue gas has a great influence on the denitration efficiency. (such as the cyclone inlet area mixing effect is better).
If the mixing is insufficient and the reaction time is not enough, to achieve the same denitration efficiency, the operating cost will increase, and the ammonia escape of the exhaust gas will also exceed the standard. In addition, the S03 content in biomass boiler flue gas is often high, and in the low temperature zone below 280 °C, there are problems such as clogging and corrosion of sulfate. The SNCR denitration efficiency is also related to the initial concentration of nitrogen oxides in the flue gas. The SNCR denitration efficiency of the biomass boiler is 20% to 50%.
〇3 oxidation technology
NO% oxidation is oxidized by a strong oxidant and finally converted into nitric acid or nitrate. The commonly used oxidants are hydroxyl radicals H0_, 03, H202, Mn04_, C102, Cl2; among them, 03 is a commonly used oxidant, and the reaction rate is fast, in the case of flue gas. When fully mixed, the oxidation rate is over 90%, and the operation is stable, and the industrial application performance is high. 03 Oxidative denitration suitable temperature is 50 ~ 180 ° C, and no requirement for S02 concentration, can be installed in the low temperature flue gas section, after NO% oxidation, it is necessary to increase the alkaline substance absorption system to absorb the oxidized nitrogen oxides.
The technical options for different emission indicators, the original pollutant concentration, and the smoke emission index requirements, can choose technical solutions with feasible technology and low operating costs. Biomass boiler users can choose the appropriate desulfurization according to this table according to the characteristics of biomass boiler flue gas, combined with biomass fuel to choose the appropriate denitrification scheme.
The above contents are all detailed introductions on the desulfurization and denitrification of biomass boiler. I believe that everyone has received a lot of help after reading them, hoping to use it better.