Italy’s power market took a huge step forward in July 2008, when the country’s power utility, Enel, opened the first of three units at the refurbished Torrevaldaliga Nord coal power plant in Civitavecchia, north of Rome.

The unit was converted from oil to coal power, aiming to help reduce Italy’s heavy dependence on oil. As a result of the high oil concentration in the energy mix, Italian consumers’ energy bills are 30 percent higher than the European average.

Torrevaldaliga Nord sees the future of power generation in Italy being driven through the utilization of coal power. The company has employed the most advanced technologies available and as a result, the coal power plant will be the most efficient in its class and one of the cleanest worldwide.

The problem

Sulfur dioxide is a severe pollutant and when released into the atmosphere, it causes acid rain to occur. At the Torrevaldaliga Nord site, the sulfur dioxide is removed from the coal combustion flue gas in the absorber towers (desox towers). Here the acid is scrubbed off with calcium carbonate which acts as a neutralizing agent.

The process environment in absorber towers is extremely harsh because of high acidity and the presence of chlorides.

The solution

To counter these harsh conditions at the Torrevaldaliga Nord coal power plant, Enel selected Outokumpu’s super-austenitic 1.4565 steel.  The grade has been specifically developed for these working conditions. The core of the absorber towers is built entirely out of 1.4565 plate from Outokumpu.

Enel decided to use Outokumpu based on a previous positive experience of using the grade for a similar application at two Enel plants in Italy; La Specia in 2001 and Brindisi in 2002.

The results

As a result of the new absorber towers, sulfur dioxide and particulate emissions are both down by 88 percent. And nitrogen oxide emissions are down by 61 percent from the previous oil-fired operations. Overall, emissions will be an impressive 50 percent below the limits set down by the EU legislation.

Torrevaldaliga Nord’s remaining two units are under construction with similar absorber towers, being built using the same Outokumpu material. At the same time, a similar but smaller coal power facility is under construction by Enel in Fusine near Venice, employing the same material.

Enel’s plans for clean coal technology are ongoing. The company is working towards zero-emission from coal power generation, developing methods for the capture and safe containment of carbon dioxide.

Outokumpu will continue to help effect improvements in the global environment offering products that take advantage of cleaner energy sources like coal power, that fight the toughest industrial conditions.

The first of Torrevaldaliga Nord’s three absorber towers under construction: the core of the tower (the rectangular structure on the left) is built entirely out of Outokumpu’s super-austenitic 1.4565 plate. Courtesy of MHI

Torrevaldaliga Nord in Civitavecchia. Courtesy of MHI