Model NO.: D001 Usage: Industry Type: HEPA Filter Application Area: >61m² Operating Principle: Active Anion Density: >4000000pcs/m³ Transport Package: Frame Cage Origin: China Structure: Floor Standing Air Volume: >400m³/h Certification: ISO Power Source: Electrical Purifying Technology: Air Ionizer Trademark: hanzheng Specification: 60 Conception Desulphurization operation applies fume desulphurization technology, it is for operating and maintenance of desulphurization equipment, monitoring whether or not the discharging of desulphurization reaches to standard.
Flue gas desulphurization refers to the removal of sulfur oxids from the flue gas of coal or other industrial waste gas after combustion.
Our company uses rotary spray drying method (SDA) technology for fume desulphurization and dust removal.
B. Operation principle
Spray drying desulphurization process regards lime as absorbent.
The lime absorbs the fume and then mixes suitable water to make slaked lime emulsion which is pumped into the atomization device located in the absorption tower. In the absorption tower, the absorbent, which is atomized into small liquid drops, mixes with fume and reacts with SO2 to generate CaSO3. Finally the SO2 in the fume is removed. At the same time, the water in absorbent is dried out and the temperature of fume decreases as the water evaporates. The product of desulphurization reaction and unemployed absorbent, both in dry particulate form, are taken out from the absorption tower with fume and then collected by dust collector. After the wet absorbent is injected into absorption tower, on the one hand, chemical reaction takes place between absorbent and SO2 in fume; On the other hand, the fume transfers its heat to the absorbent to make the absorbent dry. After the completion of the desulphurization reaction, offscum scrap discharges from the cone-shape outlet of absorption tower in the form of dry , so it is called half dry fume desulphurization. After desulphurization and being collected by the dust collector, the fume discharges. In order to improve absorbent utilization, a part of desulphurization ash is recycled in a pulping system .
Including desulphurization slurry preparation system (slurry pump, slurry tank, vibrating screen, stirring paddle, nitrifying pot, electronic screw weigher, lime bin), flue system, dust collector system (filter), desulphurization tower system, booster fan system, public auxiliary facilities.
D. Technological process
The desulphurization slurry preparation → desulphurization slurry atomization→ droplets in contact with the fume→ SO2 absorption and evaporation of moisture→ ash recirculation and removal.
1. Making of desulphurization slurry
Spray drying fume desulphurization system takes lime, which has CaO content as high as possible, as desulfurizing agent . Powdery lime in lime bin is sent to nitrifying pot after being weighed by electronic screw weigher to make high concentration slurry which is then sent to the mixing tank to filter out large-grained impurities. High concentrate slurry is diluted to about 20% by water in slurry tank. The prepared lime slurry is pumped to roof tank as spare for later use.
2. Atomization of desulphurization slurry
Lime slurry flows from roof tank into the rotating centrifugal atomizer automatically, and passes through the distributor to enter the atomization wheel which is high-speed rotating. Slurry is ejected into atomized lime emulsion droplets.
3,contact between fogdrop and fume
Fume in tangent direction of flow goes into volute-shaped distributor which is on the top of spray drying absorber tower, precisely, forming reverse contaction with the absorber.
4. SO2 absorbed and moisture evaporated
Fume contacts with the absorbent in the absorption tower and takes place heat exchange and chemical reaction. SO2 in fume reacts with Ca (OH) 2 to produce CaSO3 and CaSO4 powders.
In the absorption tower, it has two stages for SO2 absorbed and moisture evaporated. First stage is constant speed drying stage. It is mainly free volatilization of water on the surface of slurry. The existence of water on the surface of slurry creates a favourable condition for the reaction of absorbing SO2 . It is the process of gas-liquid reaction. About 50% absorption reaction take place in this stage with its reaction time about 1 to 2 seconds. With the evaporation of water, the solid content in the slurry increases. When there is clear solid substance emerging on the surface of the slurry, it means reaction has entered the second stage. In this stage, SO2 must pass through the solid particle surface to diffuse inwards so that it can react with the inside absorbent. So in this stage, the reaction rate will slow down.
5. Ash recirculation and removal
Some particles are collected in the spray drying absorber tower. Other particles, togethre with flying ash in the fume, enter the bag type dust collector with air current and are separated from each other. To improve the utilization of desulfurizing agent, the ash discharged from desulphurization tower and dust collector is recycled, and the rest is comprehensively utilized. System operation and control The desulphurization equipments are being constantly monitored by computers when in operation. When in operation, the amount of desulphurization slurry can be regulated according to the concentration of SO2 in the fume that enters the equipment and is discharged from the chimney as well as the temperature of fume that enters the drying tower and is discharged from the tower. According to actual amount, regulate the proportion of lime and water to prepare absorbent slurry.
When in operation, both the desulphurization efficiency and desulphurization utilization should be considered. Another parameter is the concentration of slurry.
E. Key technique
SDA desulphurization technology is a kind of half dry fume desulphurization technology. It avoids such defects like low utilization of absorbent, low economical efficiency when used in high-sulphur coal and high control requirement in the process of drying, which exist in traditional dry desulphurization technology.
SDA desulphurization makes use of the principle of spray drying. When the absorbent is injected into the absorption tower, on the one hand, the absorbent will react with SOx that exists in the fume to produce solid product; on the other hand, the fume transfers its heat to the absorbent to make the absorbent drier and drier. The products that are formed by the desulphurization reactions happening in the tower are dry powder. Some is separated in the tower and discharged from the cone-shape outlet; Others enters the electronic dust collector with the fume generated from desulphurization reaction.
F. Core Technology
Lime slurry is atomized by the atomization device located in the desulphurization tower. The atomizing wheels have high rotational speed. The absorbent slurry , under centrifugal force, is sprayed into uniform fog particles whose diameter could be less than 1μm. These dispersive particles, which have large surface areas, when they contact with fume, will take place heat exchange and chemical reaction and evaporate most of the water promptly to form solid ash with low water content.
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Product Categories : Desulphurization Operation Machine