As part of an energy rationalisation project, a major global pharmaceutical company is benefiting from a new combined heat and power plant that generates electrical power and process cooling for its site operations.

Combined heat and power (CHP) systems offer an environmentally friendly option for the provision of power and energy through the simultaneous generation of usable thermal energy and electricity. Heat can be delivered as hot water, hot air or steam, or in any combination of the three forms.

Dresser-Rand has manufactured, installed and commissioned its own cogeneration project for a major pharmaceutical company. The resulting heat energy will be used to produce chilled water via an absorption chilling plant. This cogeneration system consists of two natural gas-fuelled cogeneration units. Each unit is rated at 1.475MW electrical output and generates power at 10.4kV, three-phase, 50Hz for direct use at the facility.

Heat is recovered from the engines’ cooling and exhaust systems in the form of hot water and is fed directly to close-coupled, single-effect, lithium bromide absorption chillers, each of which produce 1.025MW of chilled water to serve cooling loads.

Efficiency and savings

The Dresser-Rand cogeneration system is designed to achieve an operational availability in excess of 92% at full load and deliver an annual electrical output of 24.2GWh with an annual cooling output of 16.8GWh. Anticipated CO2 savings, compared with conventional forms of supply, are 6,300t per year.

"This project demonstrates how the correct application of cogeneration can assist companies in delivering their energy-saving and carbon-reduction commitments, while improving their competitiveness," said Ian Hopkins, director of worldwide business development for the Dresser- Rand CHP business unit based in Peterborough, UK.

The CHP process displaces a large percentage of the electricity previously supplied by the grid. Currently, the facility operates at 65% efficiency for electricity and chilled water delivery, with an overall thermal efficiency of 77% on a gross fuel input basis (85% on a net fuel input basis).This compares favourably with importing grid power that can be generated at an efficiency level as low as 35% at the generation point, with an additional efficiency loss of 7-9% in the transmission and distribution system (and in producing chill from a conventional vapour compression chilling plant).

"The cogeneration system offers potential CO2 savings of 6,300t per year compared with conventional forms of supply."

The chillers have been assembled with all necessary pumps, heat exchangers and controls into engineered packages of the same construction as the matched gas, engine-driven generator sets and heat recovery units.

Cooling of the absorption chiller packages and engine systems is carried out by a separate cooling tower system controlled by the integrated overall scheme control system.

About Dresser-Rand

Dresser-Rand is among the largest suppliers of rotating equipment solutions to the worldwide oil, gas, petrochemical and process industries. The company operates manufacturing facilities in the US, France, UK, Germany, Norway, India, and China, and maintains a network of 39 service and support centres covering more than 140 countries.

Dresser-Rand has principal offices in Paris and Houston and reported revenues of approximately $2 billion in 2010.