Desulfurization nozzles are generally arranged in the desulfurization tower to remove sulfur dioxide and some polluting gases in the flue gas. At the same time, the desulfurization nozzle can also achieve the function of dust removal. The basic principle of dust removal by the desulfurization nozzle is to wet the dust particles with water mist to increase the particle and specific gravity, and then separate them from the atmosphere or flue gas. To make the desulfurization effect meet the standard, we must rationally arrange the desulfurization nozzles in the tower, and pay attention to six points in the design of the desulfurization nozzles in the tower. First of all, let’s first understand the application of desulfurization nozzles in the desulfurization and dust removal industry.
Application of desulfurization nozzle in desulfurization and dust removal industry
The basic principle of desulphurization nozzle dust removal is to wet the dust particles with water spray to increase the particle size and specific gravity, and then separate them from the atmosphere or flue gas. Different desulfurization processes use different nozzle forms. The material conveyed in the dry desulfurization process is desulfurization agent powder, generally using air flow nozzles. In the semi-dry desulfurization process, the limestone slurry is transported with high concentration and high viscosity. Generally, airflow nozzles are also used. The research shows that the air mass ratio and concentration are the main parameters affecting the average droplet size. The increase of the gas-liquid mass ratio leads to a decrease in the average SMD of the droplet: as the concentration increases, the SMD increases. In the wet desulfurization process, the nozzles are generally used for scrubbing the flue gas of the desulfurization scrubber, cleaning the blades of the demister, etc. The diameter of the spray droplets required by the process is generally 1300-3000pm. Considering factors such as energy consumption and nozzle friction, it is often used. Pressure nozzle.
For the pressure nozzle used in the wet flue gas desulfurization process, it is required that the components that make the liquid obtain rotary motion are as simple as possible, and because the required atomization particle size is large, a rotary pressure nozzle is generally used. On the basis of comprehensive economy and characteristics, the commonly used pressure nozzles in the desulfurization process mainly include solid cone swirl nozzles, hollow cone swirl nozzles, air cone spiral nozzles and solid cone spiral nozzles. Among them, the application of hollow cone swirl nozzle is the most common.
Because the position of the nozzle in the wet desulfurization process determines the importance of the research on the desulfurization nozzle, with the progress of the process research, the research on the nozzle is gradually deepened. At present, the application research of the pressure nozzle with limestone slurry as the medium is still less, and the research is generally carried out with water as the medium. The research on the flow field structure inside and outside the nozzle and the arrangement of the nozzle inside the spray tower is also rarely involved.
In short, as far as the pressure nozzle is concerned, its research has been carried out for more than 100 years, and a relatively complete theoretical system has been formed. However, there are relatively few studies on nozzles combined with desulfurization processes.
Six key points of layout design of desulfurization nozzle tower
Desulfurization nozzles are generally arranged in the desulfurization tower to remove sulfur dioxide and some polluting gases in the flue gas. To make the desulfurization effect meet the standard, first of all, we must arrange the desulfurization nozzle reasonably in the tower. The layout design of the desulfurization nozzle in the tower should pay attention to the following matters:
(1) Select a reasonable nozzle coverage height, which is usually determined according to the characteristics of the nozzle and the distance between the two layers of spray.
(2) Select a reasonable number of single-layer nozzles. Generally speaking, the number of nozzles is determined according to the process calculation.
(3) After the nozzle coverage height is determined, the coverage area of a single nozzle can be calculated, A0=πH2tg2{ɡ/2} (ɡ is the spray angle).
(4) When arranging the nozzles in the desulfurization tower, select the appropriate distance between the nozzles. Usually, the nozzle spacing is selected according to the number of nozzles and the diameter of the desulfurization tower, and it should be considered as a whole with the nozzle arrangement plan connecting the nozzles.
(5) Select a reasonable economic flow rate, and determine the diameter of the limestone slurry parent pipe and branch pipe according to the standard of the nozzle product.
(6) When checking the coverage of the spray layer in the desulfurization tower, not only the influence of the collision of the nozzle liquid flow with the parent pipe, branch pipe and support on the coverage, but also the coverage uniformity of all nozzles in the desulfurization tower should be considered. Only by reasonably arranging the position of the desulfurization nozzle in the tower, can the desulfurization effect be better guaranteed.
