<H1>CLOROFILI</H1>

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EMISSIONS OF THE AGAC INCINERATOR AT REGGIO EMILIA (ITALY)

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DRY PROCESS TO CLEAN THE GAS WITH SODIUM BICARBONATE AND RECUPERATION OF THE SALT RESIDUES

Results of the analitical tests from the ENEL DCO LP laboratory of the AGAC Reggio Emilia incinerator.

Photo of the AGAC incinerator at Reggio Emilia

Photo of the AGAC incinerator
at Reggio Emilia (Italy)

Target

The analytical campaign realised by the ENEL DCO LP laboratory was done to measure the performance of the bicarbonate process at an incinerator, equipped with modern gas cleaning apparatus.

The scope was to see if it was possible to reach the severest environmental limits (in this case the German normations) with a relative simple process.

Description of the incinerator

The incinerator of municipal and hospital waste has two incinerating lines, each for 100 tonnes/day. Both are equipped with bicarbonate process apparatus.

The total annual capacity of the incinerators is around 51,000 tonnes of waste.

Constructed in 1968, the incinerator has been upgraded several times:

For each incinerator line, behind the afterburners, the combustion gases are cooled in a steam generator to 200-250 °C. After that, they are cleaned from fine dust (fly ash) by an electrical precipitator (EP) with two chambers.

The dustfree fumes thereafter are thoroughly mixed with fine milled sodium bicarbonate and active carbon, direct in the gas line.

The sodium residues (NaCl + Na2SO4 + Na2CO3), resulting from the neutralisation of the acid contents of the gas are separated in a second filtration system, realised by bag filters.

Caracteristics of the gas cleaning process

Date of first start of the new bicarbonate process (with double filtration): January 1995 (line 2), October 1995 (line 1).

Description of the analitical campaign

The analitical campaign was executed in two phases:
The first phase from January 22 to February 2, 1996, the second from July 8 to 12, 1996. The interval between the two sampling periods was used to tune the active carbon dosing system.

The activities mainly were based on taking samples and succesive analyses of the main components. The sampling was effectuated at three points in the gas line. The following figure gives a general scheme of the incinerator and the location of the sampling points.

General scheme of the incinerator and location of the sampling points

processo AGAC Reggio Emilia

The analyses of gas composition for the determination of HCl, SOx, NOx, O2 and CO content at the points P2 and P3 was performed by online IR emission spectrophotometers type MIR 9000.

To analyse other elements and compositions, ad hoc sampling was performed, followed by analyses at the DCO/LP laboratory.

The sampling apparatus was made for the sampling of the three phases, solids, condensables and non-condensable gases. To determine the total contents of micro-elements, it is necessary to examine all three phases separately. The sampling time was app. 10 hours, to allow the collection of a sufficient amount for the following analyses. For the organic microcontaminants, 24 hours of sampling time were necessary.

For the dioxin analyses, a massa spectrometer was coupled with the gas chromatograph (GCMS), For the analyses of inorganic micropolluants was used a plasma mass spectrometer (ICP-MS) was used, a plasma mass spectrometer with atomic emissions (ICPAES), an atomic absorption spectrometer with hydrogen generation (FIHGAAS) and an ion chromatograph (IC).

The detection limits of the analytical techniques used were:

Be, Cd, Co, Cr,
Cu, Mn, Ni,
Pb, Hg, Sb		 0.003 µg/Nm3

As, Se, Sn
 		 0.03 µg/Nm3
dioxins
and furans		 0.08 ng/Nm3

The results of the analyses are exposed in following table:

Results obtained with the sodium bicarbonate process
for the cleaning of gas from the incineration of municipal and hospital waste

Polluent 
mg/Nm3 11%O2		 At the entrance
of the cleaning
system		 Emissions after
the bicarbonate
process		 German
normation 17a
BIm Sch V
of 1990		 D.M. 12/7/90
(Italian
legislation)
Particulates   2-7 10 30
HCl 1070 < 5 10 50
HF 4 < 0,02 1 2
HBr < 0,04 < 0,04   5
HCN 0,002 < 0,001   not normated
SOx 150 ± 20 1-18 50 300
NOx 140 ± 20 130 ± 20 200 not normated
Substances
Class 1.1 		   49x10^-6 0,1 0,1
As+Co+Ni 0,036 0,009 1 1
Se + Te 7x10^-3 0,1x10^-3   1
Cd + Tl 0,211 0,5x10^-3 0,05 (+Hg) 0,2
Hg 0,54 0,009 0,05  
Sb +Cr +Mn +Pb
+Cu +Sn +V		 7,05 0,0029 1 5
PCDD/F
mg/Nm3 11%O2
ng/Nm3 (TE NATO)
11% O2		 0,3 x 10^-4
0,95		 0,6 x 10^-6 
0,085
0,1		 0,004

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Conclusion

The analyses demonstrate that the Italian and German laws are respected at all required levels.

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You are at level three of the Chlorophiles pages.

Created: May 3, 1997.
Last update: September 8, 2001.

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