A solution containing sulfuric acid (H2SO4) in water is recirculated in a loop
process. The chemical reagent is introduced at the top of the vertical tower through
a distribution system designed by Drizgas Tech and travels down through and across
the media bed. The random packed mediais typically made from polypropylene material
and is resistant to the low pH of the solution.
The media bed is supported by a false bottom that separates the media bed from the
solution tank below. Then the air travels upward it meets the acidic solution and a
reaction occurs to neutralize the ammonia gas.
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).
The most common acid used in air scrubbers is Sulfuric Acid, due to its
availability, low cost, and non-volatility. The product formed when Ammonia is
scrubbed with Sulfuric Acid is Ammonium Sulfate, which is a common fertilizer
ingredient.
Caustic can be used to adjust the pH of the waste stream prior to disposal.
The resulting byproduct, a form of salt, is collected and removed through the
wastewater blow-down, as the treated air stream is exhausted through the stack.
Due to its toxicity, ammonia gas is a regulated compound that needs to be treated
below established limits before it is released into the atmosphere.
Depending on the quantity of NH3 being scrubbed, the Ammonium Sulfate by-product may
be utilized as an additional revenue stream. Ammonia air scrubbers incorporate a
variety of gas-liquid contacting techniques, including packed beds, spray chambers,
and water jets.
Explanation
Ammonia occurs as the by-product of a number of industrial and chemical processes.
It can be highly corrosive to certain metals and other materials.
Drizgas Tech is one of the leading manufacturer of Ammonia gas scrubber in India. We
offer complete packages for our dry, wet or packed scrubber systems, including
instrumentation and controls, skid-mounting of equipment, acid storage tanks,
metering pumps, and installation.
The ammonia scrubber uses a packed bed absorber to remove ammonia from a gas stream.
Sulfuric acid is used as the scrubbing solution. The ammonia scrubber can handle
high inlet concentrations of ammonia.
Ammonia is a colorless gas made of nitrogen and hydrogen with a strong and
distinguishable odor that occurs naturally in air, soil, and water and is also a
by-product of the normal biological processes of humans and animals.
Ammonia is poisonous if inhaled in great quantities and irritates the eyes, nose,
and throat in lesser amounts.
Exposure limit of ammonia
OSHA: Permissible Exposure Limit: 50 parts per million (ppm) averaged over an eight
hour work day. This is the standard that must be met in every work place.
NIOSH: Recommended Exposure Limit (REL): 25 ppm averaged over an eight-hour work
day. NIOSH also says that there should be a Short Term Exposure Limit (STEL) of 35
ppm during any 15 minute period in the day. No worker should be exposed to more than
that amount over any 15 minute period.
Chemistry of Ammonia with H2SO4
This is often by reacting the sulfuric acid with ammonia, or ammonium hydroxide
solution, to make ammonium sulfate, (NH4)2SO4.
2NH3 + H2SO4 —-> (NH4)2SO4
Ammonia + sulfuric acid → Ammonium sulfate
Features
Can handle air flow rate from 100 to 30,000 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 %
Advantages
Can handle high temperature streams
Versatile
Processes high moisture streams
Smaller space requirements
Can be retrofitted into current equipment (in some cases)
Provides cooling of heated gases
Higher removal capabilities than other equipment
Lower cost of purchase
Can remove gases and particulates, in a single unit
Able to neutralize highly corrosive gases and dusts
No secondary dust source
No temperature limits
Can handle highly flammable dusts, with very little risk of
explosion
Several customizable options, based on specific output and
applications, often allowing for a reduction in cost.
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
Applications
Storage room exhaust scrubbing
Emergency ammonia scrubbing
Storage tank vent scrubbing
Process vent scrubbing
Textile industries ammonia scrubbing
Fertilizer industries ammonia scrubbing
Phone Number
+91 842 823 1593 | +91 995 287 7991
Email Address
sales@drizgas.com | info@drizgas.com
Office Address
No. 50, Villianur Main Road, Odiyampet, Puducherry - 605 110, INDIA