Promoting clean technology Nuova Solmine

pRoMoting clean technology

Italy’s Nuova Solmine is at the forefront of the drive to reduce emissions and minimise environmental impact in the European chemicals sector.

Nuova Solmine is a leader in the production of sulphuric acid in Italy and the Mediterranean basin. It operates a double absorption sulphuric acid plant with a capacity of approximately 1,700 mt/d in Casone di Scarlino, Tuscany.

Central to the company’s concern for minimising the environmental impact of its processes is its continuous investment in clean technology. A key part of its operation involves the use of demineralised water.

Its demineralised water production plants are fed with river and well water that has first been sterilised, filtered, and softened. The Scarlino plant, (with a production capacity of 100 cubic metres per hour, and stocking capacity of 1200 cubic metres) uses a part of the water to produce steam. The remaining water is sold to neighbouring industries for use both internally and for bottling. The steam from the heat produced from the combustion of sulphur and methane, in the sulphuric acid exothermic process, is then used to produce electric energy which is used in the plant or transformed (130KV) in the sub-station so that it can be put into the national grid. Approximately half of the normal production of energy is sold and the remaining part is for consumption by the Scarlino plant.

New FAT

In late 2019 Nuova Solmine took another major step in meeting its low emissions goals with the bringing into service of a new Final Absorption Tower (FAT) at the Scarlino plant.

“We wanted to replace our old final absorption tower with a highly efficient new tower that would guarantee constant reliable emissions control and not require as much maintenance as the last one did,” said Gabriele Pazzagli, Scarlino Site Manager, Nuova Solmine.

DuPont Clean Technologies was awarded the turnkey contract to design, execute, supply, and erect a replacement tower made of lightweight and corrosion resistant MECS® ZeCor® alloy in July 2017.

From start to finish, the project took 11 months to complete with the replacement of the old brick-lined tower taking place during a planned plant turnaround in August 2018.

To date, the new MECS ZeCor FAT is performing well, achieving a pressure drop that is under the contractual target, as well as Sulphur Trioxide acid mist emissions well below the environmental limits.

The design of the MECS ZeCor alloy FAT tower at Nuova Solmine is the result of several years of research, during which DuPont Clean Technologies developed alloy towers with improved absorption efficiency and acid distribution. The new towers also bring a reduced pressure drop, a decrease in packing height and lower operating costs. These qualities have provided Nuova Solmine with a very effective and timely way to meet its emissions, maintenance, and installation goals.

Zero emissions

Nuova Solmine’s Casone plant covers around 140 hectares of land and has an annual capacity of approximately 600,0000 tonnes. Sulphuric acid is produced at the plant using the ‘contact process’. This process has significant advantages for both energy use and the environment given that sulphur combustion and its successive oxidation do not produce any carbon dioxide gas emissions. It eliminates the waste from the original procedure of baking the pyrite and significant heat production is generated that allows a large quantity of energy to be produced with zero carbon emissions.

Because of its purity, the sulphuric acid produced by Nuova Solmine has many uses in industrial processes, including water purification, synthetic fibres, explosives, pharmaceuticals, pigments, batteries, paper, detergents, tanneries, plant protection products, fertilisers, plastic materials, foodstuffs, and in the iron and steel industry.

Acid from waste

Nuova Solmine’s Serravalle Scrivia plant, near Genoa, produces approximately 75,000 tonnes of sulphuric acid and oleum a year through the treatment of waste containing sulphur and by regenerating spent acid. As a result of its use of advanced technology and the highly specialised skills of the personnel, the sulphuric acid is guaranteed a high grade of quality and purity comparable to that produced from sulphur, while at the same time contributing to the protection of and respect for the environment through the recovery of waste that would otherwise be disposed of.

The plant works in a continuous cycle, thus guaranteeing that clients can deliver their waste products all year round and avoid the typical problems associated with such deliveries to other recycling organisms. The ample stocking facilities available for various types of waste are an added advantage.

mediterranean markets

Nuova Solmine’s market is both domestically in Italy, where it is the leading company for the sulphuric acid and oleum, and several other countries, with particular focus in the Mediterranean - Spain, Morocco, Algeria, Tunisia, Israel, Turkey and Greece. Significant sales are also made to Portugal and South America where sulphuric acid plays a major part in the production of metals and fertilisers. Foreign sales are made directly to clients or through international trade. Nuova Solmine sells not only its own sulphuric acid but also sulphuric acid from various production sites abroad.

The most important, and closest, foreign market is Spain (notably the Barcelona area) where, in 2012, Nuova Solmine founded its own company, Nuova Solmine Iberia, with its own storage for local distribution. Nuova Solmine distributes its products through tanker trucks and other important facilities. The Scarlino site has a direct pipeline connected to a pier for charging vessels. It has also a railway junction that allows acid and oleum to be moved by train in special containers to its clients.

Nuova Solmine plants work on a continuous production cycle, 365 days per year to produce 670,000 tonnes of sulphuric acid per year, using about 210,000 tonnes of sulphur purchased from the main Italian refineries. Acid and oleum are stored in dedicated tanks of 76,000 tonnes of volume. Storage tanks charged on vessels are also used for national distribution. In 2013, Nuova Solmine invested in a logistics platform in the port of Vasto from which it supplies clients in the centre and the south of Italy.