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Diesel Engine Technology: Capturing reliability

The Ramco Group, with an annual turnover of over $200 million, is one of the leading industrial groups in southern India with activities in cement, textiles, IT software and a number of other sectors. In Rajapalayam, the group runs its textile operation where good quality as well as reliable and economical power is of critical importance.

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The group therefore decided to embark on a captive power project, installing diesel genset units at its textile mills in the area to provide reliable baseload power. Ramco awarded the turnkey contract to execute the project to MAN B&W of Holeby, Denmark, which will supply 16 generating sets through Powerica Ltd., its authorized and exclusive dealer in India.

The project involves the installation of ten MAN B&W type 6L23/30H and six MAN B&W type 7L23/30H Holeby gensets operating on heavy fuel oil (HFO) at six Ramco textile mills in Rajapalayam. The project originally called for six power plants to be installed, one at each site with a 2.5 MW engine. The rating and plant configuration of the HFO gensets, which will operate at 750 r/min, 50 Hz, 415 V, are shown in Table 1.

The market for these units is growing in India, particularly in medium scale industries such as textiles which need good quality, reliable and economical baseload power with a minimum dependence on standby sources of power. Although the oil price in international markets has also had an influence on the demand for such units, the increasing cost, deteriorating quality and reliability of grid power in India has been an overriding factor. MAN B&W says that it is receiving an increasing number of enquiries from markets like India for generating sets based on HFO-burning medium speed engines in the 500-2000 kW range.

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Through this project, Ramco’s dependence on a standby source of power has been greatly reduced due to the flexibility provided by the configuration of HFO gensets in the mills. If any of the MAN B&W generating sets installed at the six sites becomes unavailable, then standby gensets running on diesel oil will be used, providing up to 50 per cent plant capacity. In the event that these units are also unavailable, Ramco will be able to import power from the grid.

Cost reduction

These HFO sets for captive base load are being installed in place of standby diesel gensets in existing powerhouse buildings in order to minimize the expenditure on civil works. The power will be generated at 415 V, and this has also enabled the use of the existing 415 V power evacuation and distribution system of the mills by the project, ensuring use of existing facilities and bringing down overall project costs.

Figure 1. MAN B&W will install 16 L23/30H generating sets running on heavy fuel oil at the Ramco sites in southern India
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The plants will be equipped with highly reliable and advanced PLC and Scada systems for on-line central monitoring and recording of all critical and important parameters, along with on-line alarm systems. These baseload HFO gensets will run in synchronizing mode and will be equipped with automatic digital synchronizing systems with total power monitoring.

The auxiliaries and control systems for all the six plants have been engineered, manufactured and supplied by Powerica Ltd., using state-of-the-art technology. The control systems include genset monitoring and protection panels complete with auto-synchronizing modules with active and reactive load sharers, power monitoring controls and fault diagnostic capabilities. The PLC-based Scada system will include data logging features, screen pictures and energy generation/consumption profiles.

Modular as well as advanced HFO treatment and handling systems will be used to help ensure high reliability and plant availability. The treatment of the HFO will take place on-site and with proper sludge disposal arrangements. The HFO fuel will be passed from the preheated storage tanks to the buffer tanks by a set of electrically driven transfer pumps. The fuel is then passed to the service tanks via fuel centrifuges, and then on to the engines. Each engine will have its own HFO supply unit and will also be equipped with a diesel oil feed from the existing diesel storage facilities on-site.

The operation and maintenance (O&M) services will be provided by Powerica, which has already established its infrastructure at the sites to look after all 16 HFO gensets.

Proven efficiency

The L23/30H is a well proven engine that has been in service with the world merchant fleet and power plants for a number of years. It has a history of reliable performance which confirms that it is a durable genset with high availability under a wide range of operating conditions.

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The L23/30H series of engines has an in-line configuration and a power range of 525-1280 kW. The engine models have between five and eight cylinders and operate at either 720, 750 or 900 r/min. The engines have a bore of 225 mm and a stroke of 300 mm. The ten 6L23/30H gensets, which will be delivered to four different Ramco sites, are rated at 770 kW, while the six 7L23/30H units are rated at 900 kW.

MAN B&W has produced more than 4400 gensets of the 23 series type. Around 98 per cent of all MAN B&W Diesel Holeby’s gensets are delivered for operation on HFO, and Holeby has a market share of 40 per cent for marine gensets delivered in the power range 500-5000 kW. In the stationary market, it has a market share of 27 per cent for gensets in the power range 500-5000 kW operating on HFO.

Reliability has been engineered into the L23/30H. It has a very rigid base frame, an underslung crankshaft that keeps combustion and inertia forces in the same component and connecting rods with a high tensile strength.

And, as with other Holeby engines, quality in every component and comprehensive factory testing mean daily maintenance requirements are kept to a minimum and that there are long intervals between overhauls.

The L23/30H is synonymous with reliable power supply and economical operation, even in extreme conditions. Unlimited low-load/no load operation on HFO is combined with conformity to today’s rigorous environmental requirements. Among the features of the L23/30H are:

Lambda controller: A built-in lambda controller greatly increases the units load-response capababilities and limits the fuel oil index during the start-up procedure; it reduces smoke formation, giving a cleaner exhaust.

Tailor-made solutions: The modular engineering concept and the wide range of optional equipment mean that the L23/30H can be matched to the specific requirements of the operator.

Constant-pressure turbocharger: The constant-pressure turbocharger system consists of an exhaust-gas receiver, turbocharger, charge-air cooler with water-mist catcher and charge-air receiver, the last two incorporated in the frame. The turbocharger is a high-efficiency design, with radial-flow gas turbine and radial-flow compressor.

Easy installation: Installation is easy, as the engine and the alternator are mounted on a single base frame and connection to external systems is problem-free. The genset is delivered in a ready-to-start state, speeding up the installation and commissioning process.

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Established design: The L23/30H has been built in large numbers since its introduction. Its monoblock engine-frame incorporates cylinder block, crankcase, charge-air receiver, cooling water jacket, camshaft and camshaft drive. The under-slung crankshaft keeps combustion and inertia forces within the same component, enhancing the L23/30H’s reliability, durability and availability.

Environmentally friendly: As well as low fuel oil and lubrication oil consumption, the L23/30H meets current and adopted future environmental requirements.

The commissioning of the six plants was due to start on 20 August 2000 and will be completed by September 15. The power plants will start commercial operation immediately after commissioning.