HCL Gas Generation Sulphuric Acid Route
Commercial hydrochloric acid is available in the market as 30% aqueous solution and is widely used in industry in large quantities. But for certain application e.g. in bulk drug/ pharmaceutical industry HCL gas is required in anhydrous state for critical reactions where moisture cannot be tolerated. Such users generate anhydrous HCL from commercial grade for their captive consumption. Several methods have been adopted but generation through SULPHURIC ACID ROUTE is the most reliable and handy technique.
1. Operational reliability – the unit can be started/stopped in seconds.
2. Compact and continuous unit – all operations viz. drying, mixing, gas generation and cooling achieved in same unit.
3. Available in wide range capacities – from ± 5kg to 200kg/hr of dry HCL.
4. Except cooling water no other utility e.g. Steam, chilled water etc. are required.
5. Anhydrous gas.
6. Ease of installation.
7. Capable of operating from 25-120%.
8. Negligible pressure drop.
9. High efficiency – 99%
HCL Gas Genration Azeotropic Boiling Route
Commercial hydrochloric acid is available in the market as 30% aqueous solution and is widely used in industry in large quantities. But for certain applications e.g. in bulk drug/pharmaceutical industry HCL gas is required in gaseous form. Such users generate anhydrous HCL from commerical grade for their captive consumption. Several methods have been adopted and genertion through BOILING ROUTE is also a reliable technique.
1. Operational reliability
2. Available in wide range capacities – from 10kg to 200kg/hr of dry HCL.
3. Except commercial hydrochloric acid, no other raw-material is required.
4. The spent acid about 21% HCL usually finds use for captive consumption.
5. Capable of operating from 25-100% .
6. Easy of installation.
7. Negligible pressure drop.
HCL Gas Absorber Falling Film Type
The Falling Film Absorbers are typical Heat Exchangers with weir tube arrangement at the top – which is always vertically mounted.
In Falling Film Absorbers gas to beabsorbed enters atthe top of FFA and flows co currently with absorbent liquid coming from storage tank by pump.Heat of solution released as a result of the absorption process is removed by the cooling water flowing in the shell – side of the falling film unit. Thus noxious gas absorption is effected at lower temperatures enablinga higher absorption rate than adiabatic absorption towers.
The absorbed gas leaves at the bottom of FFA at a very low temperature for storage and disposal.
The un – absorbed gas and any inert gases also leave via vent at the bottom of FFA and enter the venturi scrubber or bottom of tail gas tower scrubber as is shown in the figure.
Falling film absorbers can be used for absorption of gases like HCl /Cl2 / So2/ NOX / HBr – where higher efficiencies of absorption are required.
1. No moving parts
2.Ease of operation
3. No maintenance
4. Can handle very large gas flow rates as well variable gas flow rates
5. Very less area required for installation
HCL Gas Absorber Tower Adiabatic Type
HCL absorption columns are used for absorption of Hydrochloric gas, which statutorily are not permitted to vent into the atmosphere, and to produce the HCI acid.
The column is constructed with a series of packed sections, a gas introduction point below that, a condenser on the top, and a cooler at the bottom. Make water is sprayed from the top and acid is collected from the bottom.
HCL absorption columns are available in 80DN to 300DN diameter (for the gas rate 10 Kgs/hr to 300 Kgs /hr approx).
Bromine Recovery Plant
The feed is acidifide with 30% HCI acid and acidified feed is fed to the scrubber by pump to Scrub uncondensed chlorine from Vent Condenser and return back to the reaction column. In some cases the part feed is preheated using effluent from the reaction column prior to the entry of reaction column and part feed is fed to the scrubber to conserve energy. Chlorine and Steam are also fed to the reaction column.
In the reaction column the feed is reacted with chlorine gas & bromine is liberated Instantly. This liberated bromine is stripped out of the solution by live steam . The bromine and water vapor stream leaves the top of the column and enters the condenser. Condensate falls into the Phase Separator where it forms two phases, the light aqueous phase (Water) being returned to the Column, while the heavy phase (Bromine) being feed the purification column. Cooling Water & Chilled Water is used as cooling media in heat exchanger provided at the top of the column to condense water vapor & Bromine.
Purification of the Bromine is achieved by distillation. Heat being introduced into the column through the reboiler. Bromine and Chlorine vapor leave the top of the Column and enter the Condenser. The Bromine gets condensed in the Condenser and falls back into the column while uncondensed chlorine vapor along with traces of Bromine escapes from the Condenser and enter into the Vent Condenser, where remaining Bromine gets condensed and back to the crude Bromine receiver. Pure bromine is cooled in a product cooler and goes to Product receivers. Guard condenser is also provided at the top of the receiver to prevent escape of bromine. Bromine is then collected in glass bottles.
From Industrial Effluents (NaBr/KBr/HBr) From Sea-Bittern. Available up to 600mm Dia.