Types of Technology

• Drizgas Tech is leading Wet Scrubber manufacturers in Indiafor Boiler flue gas. We design and manufacture wet scrubber to suit the customer’s requirement.
• Wet Scrubbers are the pollution control devicesusually installed in the path of the flue gases to extract Sulfur compounds or oxides of sulfur such as Sulfur Dioxide (SO₂) and Ash particles. Wet Scrubbers are called so because of the scrubbing action of gases in contact with water to scrub off dirty particulates or gases that cause air pollution.
• The general composition of a fuel is a mixture of Carbon (C), Hydrogen (H), Sulfur (S), Oxygen (O), Nitrogen (N) and other elements. Combustion of fuel with air generates flue gases that contain Sulfur Dioxide (SO₂), Carbon Dioxide (CO₂), Ash, Water vapor (H₂O).

Highlights

• Flue-gas desulfurization(FGD) is a set of technologies used to remove sulfur dioxide (SO from exhaust flue gases of fossil-fuel power plants, and from the emissions of other sulfur oxide emitting processes such as waste incineration.
• Packed-bed scrubbers consist of a chamber containing layers of variously shaped packing material, such as Pall rings, Raschig rings or Berl saddles that provide a large surface area for liquid-gas contact. The packing is held in place by wire mesh retainers and supported by a plate near the bottom of the scrubber. Scrubbing liquid is evenly introduced above the packing and flows down through the bed. The liquid coats the packing and establishes a thin film. The pollutant to be absorbed must be soluble in the fluid. In vertical packed bed scrubber, the gas stream flows up the chamber (countercurrent to the liquid).
• Physical absorption depends on properties of the gas stream and liquid solvent, such as density and viscosity, as well as specific characteristics of the pollutants in the gas (e.g., diffusivity, equilibrium solubility). These properties are temperature dependent, and lower temperatures generally favor absorption of gases by the solvent.
  

Mechanism

• Gas scrubbing plants for process and environ – mental technology. We specialize in jet and Venturi scrubbers which are used with a high success rate in the field of process and environmental technology for cleaning and de-dusting discharge air, absorbing noxious gaseous substances, separating aerosols and cooling gases.
• We offer a series of standard scrubber types, which can also be combined depending on the application: Jet scrubbers types I and II Hot gas scrubbers (Quench) / flue gas scrubbers Packing towers Venturi scrubbers Capacity ranges from 0.05 m3 /h up to approx. 100,000 m3 /h gas throughput with exhaust gas temperatures of up to 1,300 °C.
• Jet scrubbers are particularly suitable for use with ex – plosive gas mixtures and heavily dust-laden and highly corrosive gases. They can also be conveniently installed into existing plants at a later date.
• The quench head is positioned directly in front of the jet scrubber. The hot discharge gas is cooled down to substantially lower temperatures than 100 ºC by spraying in scrubbing liquid before the noxious substances are absorbed in the jet scrubber and rough separation of the dust possibly takes place.
• The gas and the liquid phase are separated in the centrifugal separator which is arranged downstream. Tower packing, which guarantees the cleaning of exhaust gases down to emission limits, is usually incorporated in the separator. A droplet separator prevents the entrainment of scrubbing liquid.
• The plants are designed to reduce halogen and halogen hydrogen and sulphur compositions down to the required exhaust gas limits. In the process a light alkaline scrubbing solvent is circulated. If the hydrochloric acid concentrations in the flue gas are very high, the plant can also be designed to include HCl recovery. These plants can also be easily extended with Venturi scrubbers for fine dust or aerosol separation, catalytic plants for the removal of nitrogen and active carbon adsorbers for the separation of heavy metals.
• Additional packing or trays are installed into the scrubber’s separator as counter-flow columns for fine cleaning. Depending on the particular application, jet scrubbers can also be designed with several effects or combined with Venturi scrubbers or aerosol separators.
• Pure water, diluted acids or caustic solutions are used as scrubbing medium. As a result, the scrubbers are very well suited to the absorption of halogens (F2 , Cl2 , Br2 , J2 ), halogen-hydrogen (HF, HCl, HBr, HJ), sulphur compo – sitions (SO2 , SO3 , H2S), ammonia (NH3) together with low molecular alcohols, carbon acids and amines).
• If the exhaust gas contains a sufficient concentration of only one noxious substance, there is the possibility of recovering this from the exhaust gas: Hydrochloric acid recovery Production of ammonia solution Production of sodium hydrogen sulphite Production of chlorine bleaching Depending on the strength of the chemicals, the plants can be supplied in metallic material, coated steel, thermo – plast or fibre-glass reinforced plastic.

Features

• Can handle air flow rate from 100 to 100,000 CFM
• Removal method is Absorption / Chemisorption
• Material of Construction: PP, FRP, PP+FRP, MS+FRP, SS 304, SS 316
• High efficiency Tellerette^®Tower Packing removes soluble/reactive gases, solid particulate and liquid droplets down to 7 microns
• Lower shell serves as integral sump for recycle of liquid
• Spray nozzles accessible from top of unit
• Entrainment separators prevent liquid carryover
• Special multi-bed packing designs accommodate different scrubbing solutions for removal of multiple contaminants
• Efficiency up to 99 %

Additional accessories

• Continuous pH monitoring system for scrubbing liquid
• Dosing system for adjusting pH
• PLC operated control panel
• SCADA system

Design considerations

• Air flow rate of exhaust gas
• Velocity across the column
• Pollutant concentration in the gas
• Solubility of pollutants in solvent/water
• Reaction rate
• Liquid to Gas (L/G) ratio
• HTU (Height of Transfer Unit)
• Packing material size, shape and type
• Packing depth
• Gas temperature

Advantages of Boiler Wet scrubber

• Reduces pollution and follow the compliance of the Pollution Control Board.
• Easy operation so trained operator is not required.