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Cannon Bono Energia and A2A have built a solid business relationship, leading to the supply of various energy and water treatment plants in Lombardy, where both Groups are present with the majority of their activities

The historical relationship between Cannon Bono Energia and A2A dates from the 1970’s, when a fire-tube steam generator was supplied to one of the utility companies that later —joining forces with others examples of excellence in the field of energy —became A2A.
The reliability of that boiler in several emergencies convinced the client that this was a good product supplied by good people, and the story begun.
Today, more than 40 years later, both companies have grown significantly: in addition to the above mentioned leading presence in the electricity field, A2A is one of the main players in the environmental sector in Italy: with approximately 3 million tons of waste treated —of which over an half is used for the production of electricity —A2A ranks among the major district heating and gas operators in Italy, with sales to end customers of 2,874 GWht in the district heating segment and over 2 billion cubic meters of gas distributed. In 2011 the group achieved a turnover of Euro 6.2 billion, occupies more than 11,000 employees and is listed on the Italian Stock Exchange.

Energy, serving the communities
Several examples of good cooperation between Cannon Bono Energia and A2A can be men-tioned, all of them realised in Lombardia, where A2A owns several power plants and is leader in the field of district heating. Cannon Bono Energia has experienced several application in this market segment, having developed dedicated heat generation units.
The most popular type is based on a heater solution named CTH, a multi-tubular water tube design; these heat generators can be installed directly on the district heating networks —where network hot water circulates directly in the CTH tubes —or through heat exchangers, depending on water characteristics. Having no practical limitation on the pressure design, that can reach values higher than 40 bar, and on hot water inlet temperature, limited only for flue gas temperature consideration, the CTH has been extensively installed in most of large Italian district heating applications.
A2A installed several CTH units in their plants of Brescia, Bergamo and Sesto San Giovanni, near Milano. The CTH can reach very high efficiency as well as very low flue gas emission levels.

In Brescia, that represents the excellence reference point for all Italian district heating installa-tions, A2A has installed two 40 MW methane-fed CTH hot water heaters that quickly compen-sate the excess heat demand generating during peak hours.

The CTH design grants them a reduced start up time permitting to stop the heater when the network load is on a low demand. These huge machines were assembled in-situ using pre-built modules. A similar plant had already been supplied to the near Bergamo plant.
In both these cases the heater provides super-heated water at about 150°C to a bank of heat exchangers, that keep the water circulating in a long district heating piping at temperatures starting from 130 °C.
A different solution was required by A2A for their Sesto San Giovanni plant near Milan: here the network dimensions and its new construction design allowed the utility company to simplify the project: a significant saving was achieved by directly feeding the hot water from the heater to the circuit, without intermediate heat exchangers.

Here a 40 Mw CTH auxiliary unit works flanking an existing heater, supplying the balance of heat demanded in peak hours and replacing the main unit when it fails temporarily. Designed and built for unattended operation, this heater can be supervised by the operator every 24 hours, allowing him to follow a number of other installations located nearby.

Another important installation was supplied by Cannon Bono Energia to A2A Centrali in Cassano d’Adda, close to Milan. This old power plant was originally burning coal, then it was converted to heavy fuel and more recently installed gas turbine. An auxiliary boiler was demanded to heat-up the turbine seals and provide steam for various ancillary services.

A natural gas firing CTD unit able to produce 53 t/h of steam at 20 bar and 260 °C was installed with a turn-key supply contract. This project turned out to be a very challenging task for Cannon Bono Energia specialists, that devoted a total of 16 months of work to complete the job, with full satisfaction of the client.
Stringent emission levels have always been a “must have” specification from A2A, a utility company facing tough daily exams from the public opinion and environmentalist groups, always keen in keeping them under a strict scrutiny for emissions and pollution.

The law-permitted limits, valid at the time of starting a new plant, are always drastically cut by the client, in order to be safe with their emissions also in the future, when those limits will be more restrictive.
Cannon Bono Energia always complied with the imposed specifications, combining high thermal efficiency and low emissions.

These factors were substantially the reasons for assigning to the company the supply of four thermal oil heaters OMV, providing 14 MW of power each, for the Famagosta plant located in the southern part of Milan.
Similar problems —similar solutions: the same type of oil heaters were installed in other two urban plants of Milano, the A2A Canavese and Tecnocity/Bicocca plants, where totally four OMV units (14 MW each) supply heat for the district heating network of the surrounding quarters.
Another technical solution was used for the A2A Selinunte plant, in Milano, to heat a large number of buildings owned by ALER, the town’ social housing authority.
In this case a SG fire tube boiler was supplied; this steam generator can produce superheated water directly or indirectly through a steam/hot water heat exchanger.
The availability of sophisticated electronic controls has enriched the portfolio of products offered by Cannon Bono Energia and contributed to achieve significant results in the supply of technologies to the A2A during these years.

Water, a precious resource
Northern Italy was once a very water-rich area, but things are changing rapidly: he climate changing has significantly influenced the availability of fresh water in this densely populated area.
A2A that operates in this area, is very sensitive to all water-related issues. Their thermal plants require daily huge quantities of the “blue gold” and the company spends considerable financial and logistic resources to ensure the best exploitation of the available water.
Numerous water treatment plants have been supplied in the past twenty years by Cannon Artes Ingegneria to several A2A plants in Italy. Among them, it is worth mentioning the depuration plants supplied to the two Brescia plants of Lamarmora and Brescia Nord.
The first one handles the well water used to feed the boilers: a total removal of salts is achieved in this case with a 60 m3/h plant composed by activated carbon filter, cationic, anionic and mixed bed columns.
This demineralising system provides nearly pure water: the measured electric conductivity results lower than 0.1 microSiemens/cm, the same of distilled water.
In Brescia Nord a new waste water treatment system has been installed in an existing industri-al building, whose limited space has forced Artes’ designers to draw a real “puzzle plant”.
Two main tasks were managed in this location: the removal of suspended solids and heavy metals, and the de-oiling operations by far exceeding the limits set by current laws.
A 30 m3/h chemical/physical plant handle the first requirement, by treating waste water recovered from various parts of the site with an initial neutralisation, followed by coagulation, flocculation and gravity settling of the hydrated metals obtained with the chemical process.
The use of a lamella pack clarifier has considerably reduced the volume of the treatment basins, making more easy the installation in a rather narrow space. In open air, but still not in a very wide area, is located the de-oiling plant that will treat all waters coming from the periodi-cal washing of tarred surfaces and of occasional spills. This plant will enable discharge all the treated water into the nearby river.
The whole automation system, including the signals coming from existing, still working units, has been integrated under the control of the new plant, done by Cannon Artes Ingegneria with a sophisticated hardware.
A similar plant was supplied a few years before to the Canavese district heating plant in the eastern part of Milano, in combination with the thermal units supplied by the sister company Cannon Bono Energia.
The same joint approach was used to supply the deaerator for the power plant of Cassano d’Adda.

Synergy provides positive effects
The wide range of solutions supplied by the Cannon group, the reliability of the installed equipment, a prompt technical service and a great flexibility in handling unusual requests have contributed to build a solid human relationship between the specialists of A2A and those of Cannon Companies.
A mutual trust has been consolidated in all these years, leading to fast definition of technical specifications and commercial quotes, to the advantage of a short and efficient order pro-cessing time.