By Siàƒ¢n Green
When it comes to industrial power, reliability and environmental performance are key. Italian telecomms giant Olivetti, as well as others, have chosen gas engine technology to meet these needs.
In the industrial heartland of northern Italy sits the headquarters of Olivetti, the Italian industrial holding that has evolved over the years from an electronic and office equipment manufacturer into a telecomms company. With core operations in fixed and mobile telephony as well as internet services, reliable power is key to Olivetti’s operations.
In 2001, Olivetti therefore made the decision to refurbish the cogeneration system that supplies power, heat and air conditioning to its offices in Ivrea, an industrial region north-east of the city of Turin. It selected Rolls-Royce to supply two cogeneration units to replace the existing plant.
Rolls-Royce will supply two natural gas reciprocating engines and a heat recovery system to provide power and heat to Olivetti’s offices
Under its €2.9 million contract, Rolls-Royce will supply two natural gas reciprocating engines and a heat recovery system to provide power and heat to Olivetti’s offices. The plant will also be connected to the national power grid, allowing the export of surplus electricity.
At the heart of the cogeneration island will be two 3 MWe Bergen KVGS-16G3 reciprocating natural gas engines. These will replace the existing cogeneration plant – consisting of two natural gas fired boilers and a steam turbine – which was commissioned some 40 years ago. The €8.2 million project will be overseen by Olivetti Multiservices (OMS), Olivetti’s energy services and property management subsidiary.
OMS manages the cogeneration plant and internal electricity network and heating and air condition systems that supply Olivetti’s headquarter offices in Ivrea, and will operate the new cogeneration plant when it is commissioned in November 2002.
According to Guido Baroncini of Rolls-Royce Italy, Olivetti has a long history in Italy, starting out as a typewriter manufacturer in 1908. It eventually evolved into a producer of mechanical office equipment and then into the manufacture of electronic equipment, computers, and IT systems and services.
“Eventually Olivetti exited the computer business and went into telecommunications industry,” said Baroncini. “When the telecommunication liberalization occurred in Italy, Olivetti created its own telecommunications companies, Infostrada and Omnitel. Then the company sold these businesses, and used the revenues to buy Telecom Italia.”
Telecom Italia was acquired as a result of a voluntary public tender offering by the Italian state in 1999. At its time, the €31.5 billion share launch was one of the largest in the world. Through Telecom Italia, Olivetti now has business units in fixed wire telecomms, wireless telecomms, internet services, information technology, and satellite services.
As a result of Olivetti’s past and present activities in telecomms, Ivrea has become the ‘telecomms capital’ of Italy. Infostrada – now owned by Enel subsidiary Wind – and Omnitel – now owned by Vodafone – still reside in Ivrea.
Baroncini notes that the environmental performance of the new power plant is important to Olivetti and OMS. The design of the engines and the use of natural gas as a fuel will ensure that the plant meets and exceeds Italian standards for noise and emissions. This will ensure that Olivetti’s neighbours will be happy, says Baroncini: “The office of the Italian environmental authority is right across the road!”
As the lead contractor to the project, Rolls-Royce will be responsible for completion of the entire cogeneration units from design and manufacture through to the installation, commissioning and entry into service of the power plant. The company will supply the entire range of expertise and equipment that the power plant will require, including the cogeneration module, heat recovery boiler for hot water and steam production, engine room accessories, boiler pumps, switchgear, ventilation system and auxiliary items.
The two Bergen engines will, between them, produce 6 MWe, and 6 MWth as steam and hot water to feed the Olivetti medium voltage power and heating/air conditioning networks. The two engines will meet all of the Olivetti complex’s needs for electricity, heating in winter, and air conditioning in summer during normal load periods. The average baseload of the office complex is around 4 MWe.
During times of peak load – usually a maximum of around 7 MWe – two 5 MWth gas boilers will be used and electricity will be imported from the grid. As the power plant operates in parallel with the national grid, it will be able to export power to the grid during periods of low demand.
The engine exhausts are connected to waste heat recovery boilers which produce 6 bar saturated steam and hot water at 95à‚°C. In winter, this is used for heating and in the summer months, absorption chillers produce chilled water to provide air conditioning.
A popular choice
According to Baroncini, there are now just under 70 Bergen gas engines operating in Italy, all of which are in cogeneration applications. The engine’s efficiency and environmental performance make it a popular choice with industrial companies requiring power and heat. Apart from the Olivetti project, one of the most recent projects in Italy is in Avezzano, near Rome, where nine KVGS-18G generator sets form the heart of a cogeneration plant.
The KV-G3 family of gas engines is ideally suited to cogeneration applications, says Rolls-Royce, and has undergone progressive technical development since it was first launched in 1991. It is based on the same frame as the Bergen K-type diesel and heavy fuel oil engine, and share many of the same mechanical components There are now over 240 KV-G3 engines in operation around the world, and reference plants with over 55 000 running hours.
The two Bergen engines will produce 6MWe and 6 MWth
Rolls-Royce acquired the Bergen engine family in 1999 through its acquisition of Vickers Ulstein Bergen, designers and manufacturers of four-stroke medium speed engines for power generation and marine propulsion. Engine production is based in Bergen, Norway.
The KV-G3 gas engines use lean combustion technology and pre-chamber ignition to produce an output of 185 kWe per cylinder at an efficiency of nearly 43 per cent. The engines are more efficient than earlier spark-ignited gas engines, and also have lower NOx emission levels.
The KVGS-16G3 engine is a 16-cylinder medium speed unit producing 3000 kWe and around 2800 kWth of exhaust heat. It has a common skid, engine and alternator unit and its advanced control system allows individual adjustment of ignition energy and timing for each cylinder.
Air is drawn in by the turbocharger, through the intercooler and into the cylinder. A timed mechanical gas valve injects gas under slight overpressure into the air inlet stream to ensure a homogenous and lean mixture of air and gas.
Energy available from the Bergen KV-G3 lean-burn gas engine range, which is ideally suited to cogeneration applications
Air pressure is controlled by the variable turbine geometry while gas flow is controlled by mechanical valves before each cylinder. The gas pressure is set electronically by the pressure regulating valve on the gas supply module ahead of the engine. An air flap for each cylinder restricts the air supply during start up and low load operation.
As the pressure in the cylinder is low, gas is admitted into the small pre-chambers – one in each cylinder head, electronically controlled by the same pre-chamber pressure unit. During compression, the lean charge in the cylinder is partially pushed into the pre-chamber, where it mixes with the pure gas to form a rich mixture that easily ignites by the spark plug. Fast and complete combustion of the main charge in the cylinder is ensured by powerful ignition discharge from the pre-chamber.
Advanced electronic engine management ensures the operating parameters of the engine are adjusted and optimized in relation to each other. The system sets the optimum main and pre-chamber gas pressures, the air-fuel ratio, the fuel rack position, the ignition timing and the air throttle position.
The alarm and monitoring part of the system includes a number of built-in safety functions in order to ensure safe operation and high availability. It is designed to protect the engine and signal any fault that arises. It includes a misfiring detection system based on analysing different operational parameters and a knock detection system with individual knocking sensors in each cylinder.
The KV-G3 gas engines use lean combustion technology and pre-chamber ignition to produce an output of 185 kWe per cylinder at an efficiency of nearly 43 per cent
The complete engine management, control and monitoring system sits in a cabinet next to the engine and communicates with plant control through a single cable.
The cogeneration power plant will operate unmanned and will be remotely controlled by OMS from its main offices. The control and instrumentation system for the plant is based on a PLC system – one PLC for each engine and for the heat recovery system – connected by a common bus to a DCS system supplied by Invensys.
OMS will source natural gas supplies for the power plant from the wholesale market.
Maintenance of the power plant will be carried out by Rolls-Royce under a service agreement. During periods of maintenance, electricity supplies will come from the national grid, while the two 5 MWth gas boilers on site will provide the necessary steam and hot water for the complex. In addition, the two Bergen gas engines are able to operate independently of each other, providing OMS with additional flexibility.
Avezzano – An expanding operation
In Avezzano, a town in the mountains to the east of Rome, nine Rolls-Royce Bergen KVGS-18G powered generator sets form the heart of a cogeneration plant operated by Micron Technology Italy S.r.l. The plant is one of the largest of its kind in Europe, and provides 27 MWe and 33 MWth to Micron’s industrial facility.
Situated close to the Abruzzo National Park, the cogeneration plant meets strict Italian requirements for exhaust emissions. The NOx and CO emissions at five per cent O2 and 75 per cent load are 350 mg/Nm3 and 500 mg/Nm3 respectively. These levels are achieved by using oxidizing catalyzers for CO.
The industrial processes at Micron, which manufactures high quality memory devices for personal computers, cell phones, digital cameras and other products, requires a continuous supply of electric power with a narrow frequency band every day of the year. Power supply reliability is therefore crucial.
The nine generator sets on site are powered by Bergen spark-ignited KVGS-18G lean-burn gas engines driving Leroy Somer electrical generators. Six units were installed in 1995, a seventh was added in 1996, an eighth in 1999 and engine number nine was installed in 2001. The engine is robust and reliable and is able to operate for long periods between overhauls.
Heat from the lubricating oil, the high temperature charge air and jacket water is used for hot water production at 85à‚°C. For steam production, the exhaust gas is cooled from 420à‚°C to 166à‚°C in 12 bar exhaust gas steam boilers.