Intervento di Ruggero Corazza, Alles SpA Conferenza Finale Progetto GREEN SITE: “Supercritical fluid technologies for river and sea dredge sediment remediation”. LIFE 10 ENV/IT/343. Venezia, 13 dicembre 2013

1. Project GREEN SITE
“Supercritical fluid technologies for
river and sea dredge sediment
remediation”
– LIFE 10 ENV/IT/343 –
Ing. Ruggero Corazza – ALLES S.p.A.

2. What’s a supercritical fluid
Definition:
Super-critical state: in conditions over their
critical temperature and pressure, fluids and
their behaviours become partly like liquids
(p.e. density) and partly like gas (p.e.
propagation).
Water and Carbon dioxide, in supercritical
conditions, are able to dissolve organic
compounds.
Sub-critical state: in conditions of temperature
and/or pressure a little below its critical ones,
only some properties of a supercritical fluid
have been acquired.

3. 1st Phase: Extraction of the pollutants
using supercritical CO2 and subcritical H2O
Inlet: Polluted sediment, H2O, CO2
Outlet: H2O, CO2 , pollutants
cleaned sediment
Process Temperature 250°C
Process Pressure 300 bar
CO2 has Tcritical 31°C, Pcritical71 bar
H2O has Tcritical 374°C, Pcritical220 bar
and

4. 2nd Phase: Supercritical Oxidation of the pollutants
CO2
CO2
Inlet: H2O + Pollutants extracted
in Phase 1, air 300 bar
Outlet: CO2, H2O and salts, heat
Process Temperature 800°C
Process Pressure 300 bar

5. Extraction Reactor (left), Oxidation Reactor (right)

6. Project targets
• Over 90% abatement of organic solvents.
• Over 95% abatement of washing liquor.
• Extraction times for the target compounds: 60’ – 90’ (max 5kg)
Oxidation times of 1 l of the target compounds: 1’ – 5’
• Absence of any residual solvents and micro-organisms in the dredged
sediments.

7. Layout of the plant (Extraction + Oxidation)

8. Green Site’s plant front view

9. Green Site’s plant back and side view

10. Extraction layout during a test

11. Fase di Estrazione:test running
Extraction phase: Esecuzione
During the testing activity 2 kinds of samples have been used with 2 different
concentration levels of contaminants: one with 50mg/kg and one with
100mg/kg.
For each test about 2 kg of sediments have been treated.
Carbon Dioxide, used for extraction, has been re-used every time, while the
liquid phase exiting from the separators has been collected and analized.

12. Oxidation layout during a test

13. Oxidation phase: inlets
Oxidation tests have been carried out introducing, at first, a liquid mixture of
water and isopropyl alcohol to bring the reactor to the optimum process
conditions; then, the first mixture has been replaced by a mixture of water
and hydrocarbons (polluttants)

14. Oxidation phase: test running
For the oxidation tests we’ve used a mixture of water and aboput 7% of
hydrocarbons, in fact we wanted to verify the oxidation reaction using as fule,
only hydrocarbons. So, we needed to concentrate the liquid phase obtained
from the extraction tests separing some cleaned water from the more
concentrated mixture. In case of an industrial scale plant, for this
concentration, we are thinking about a system based on a union of floating
systems and filtration on membrane.
The performed oxidation tests have shown the ignition of an hydrotermal
flame at the expected conditions (400°C and 300 bar) and its stable
maintenance (about at 800°C and 300 bar) both with the water and isopropyl
alcohol mixture and with the water and hydrocarbons mixture.

15. THANK YOU FOR YOUR
KIND ATTENTION
For other informations:
www.green-site.net
www.alles.it
e-mail info@alles.it