Small biomass steam generator low nitrogen

2. Specific transformation plan:
(1) Increase the secondary wind. In order to achieve the deep and graded combustion of the furnace air, a considerable combustion space and recovery space are left. One secondary air nozzle is set up on each of the four corners of the furnace body (it can swing up and down, and the secondary air is placed in a high position to ensure sufficient recovery height). The secondary air duct is equipped with a sliding door. The secondary air nozzles are equipped with seals. The transformation of secondary air is the main means of controlling fuel-type and thermal-type NOx.
(2) Turn off the third wind. The tertiary air nozzle is closed, and the original tertiary air pipe is equipped with a separator. After passing through the air separated by thick and thin, the thick side enters the upper secondary air, and the light side is used as the secondary air. Bringing the tertiary air into the secondary air can reduce the secondary air volume of the original main burner range. In addition, part of the pulverized coal in the tertiary air can be sent into the furnace body in advance (compared with the original high position), because The reduction of the position is also equivalent to prolonging the combustion time of pulverized coal in the furnace in the tertiary air, which is beneficial to reducing the content of fly ash combustibles in the steam generator.
(3) Transformation of the secondary air nozzle. According to the specific plan for the change of the secondary wind shear circle in the furnace, as shown in Figure 1, three areas with completely different field characteristics and the distribution of the near-wall area are formed on the furnace body section. It can ensure that there is sufficient oxygen on the wall to avoid slagging and high-temperature corrosion without changing the direction of the main jet.

This combustion method can improve the permeability of the primary air pulverized coal flow in the furnace and keep it away from the water wall below, reducing slagging, high-temperature corrosion and ash deposition in the furnace. In addition, because the direction of the primary and secondary wind tangent circles is opposite, the mixing link of pulverized coal and air is delayed, thereby reducing the emission of NOx. In addition, the secondary air is placed tangentially, so that the primary air flow reversely rushes into the high-temperature air from the upstream, so that the pulverized coal is sluggishly concentrated in this area. Under the condition of oxygen deficiency, volatile matter is precipitated as soon as possible and ignites and burns, which is very important for stable combustion and combustion. There are benefits.
(4) Modification of micro-oil ignition. For small steam generators, replace the 2 burners in the lower layer of the original steam generator with low NOX burners with micro-oil ignition function. The device can make the pulverized coal ignite and burn quickly. After the transformation, it is not necessary to use a large oil gun when the steam generator is in operation, which saves a lot of fuel for the power plant.