Example of treatment of a mixture of
pollutants in industry
innovative "One-pot" process consists in capturing gaseous
pollutants in a physicochemical treatment whose liquid
effluents are subsequently digested by the aerobic bio-purification
process in the treatment plant.
process of absorption (capture) and organic chemical
modification of Volatile Organic Compounds (organic
This operation is carried out in a single operation
on a collection installation by physico-chemical washing.
The final destruction of the capture
products after the simultaneous process of absorption
and chemical modification
This ultimate operation (B) is carried out in a biological
The organic compounds present and formed During the
condensation reaction are digested by the process of
natural aerobic bio-purification of the purification
originality of the process resides firstly in the choice
of the reagent which combines with the pollutants to
be treated and secondly in the final natural destruction
in the wastewater treatment plant that does not generate
any new gaseous pollution.
example below describes the treatment of a mixture of
pollutants in a single operation
gas scrubbing column joins the vents of three
"pilot" reactors in chemical industry:
1 - Synthesis of an Acid Chloride
Reactor 2 - Synthesis of methyl ethyl sulfide
3 - Decarboxylation of an Acid
gaseous and volatile pollutants are composed of:
kg SO2 (sulfur dioxide) 50 mol
kg HCl (hydrochloric acid) 52 moles
of dichloroethane (solvent)
of SOCl2 (thionyl chloride)
kg CH3SH (methyl mercaptan) 6.3 moles
kg C2H5SH (ethylmercaptan) 47 moles
kg H2S (hydrogen sulphide) 5.9 moles
2.6 kg CO2 (carbon dioxide) 59 moles
Possible traces of alcohols
amounts of base and reagent are calculated on
the basis of Spreadsheet
and load sheets .
Absorption column 500 liters (column + tank),
Height: 3 m,
base area: 0.28 m2 (diameter 60 cm), plate lining,
mist eliminator at the air outlet.
Fluid circulation pump adjustable from 0 to
25 m3 / H.
Adjustable polluting effluent feed valve From
0 to 500 m3 / H.
load for a batch operation:
potash: 68 kg
reagent: 21 kg or 54 kg of solution at 40%
complementary water determined in the worksheet corresponding
to 20 volumes of the pure reagent and then in order
the calculated quantities of alkaline potassium solution
and the 40% solution of the reagent are charged into
the suction sheet.
The reaction medium displays a pH value of> 11.
The circulation pump is activated and then the gas flow
valve is gradually released and controlled at the desired
The end of reaction is determined and controlled by
The operations took place over a period of 10 hours
with a gas flow rate of 500 m3 / h.
The end of the reaction is controlled by pH-metry (about
8.5-9), and the absence of H2S and mercaptans checked
with lead acetate paper and pH paper.
clear, colorless and odorless reaction medium is then
evacuated to the plant self-neutralization pit before
being discharged to the network to be subjected to the
aerobic bio-purification process in the purification
on the unfiltered reaction medium before rejection:
<30 ° C;
287 mg / L;
670 mg /L.
calculation of the operating costs for evaluating the
economic potential of the process:
flux calculation worksheet to determine the quantities
this test, it is clear that for the destruction of the
sulfur compounds, treatment with bleach would revert
12 times more expensive than treatment with the PTC
Treatments with ClO2 or H2O2 are even more expensive.
example of chemistry treatment includes:
Complete removal of sulfur compounds.
(complete elimination of CO2).
removal of hydrochloric acid.
removal of traces of thionyl chloride.
removal of trace solvents.
also the examples of the DAVID Process - Odors