Grid supply is pasta its best

Pastas Doria, a large Colombian manufacturer of pasta products located in the city of Mosquera (near Bogotá), had been experiencing lost production time owing to frequent utility voltage instability and power failures. The factory was also suffering high electricity and fuel oil costs. In order to keep the plant’s production line up and running and at the same time save money on energy expenditure, Pastas Doria decided to install a combined heat and power system. They chose a cogeneration system based on the 1750 kW gas engine genset by Cummins Power Generation with the intention of gaining a more reliable electricity source and at the same time meeting its needs for heat to use in pasta drying.

Pastas Doria has been producing a wide variety of pasta products in Colombia for over 53 years and makes more than 50 000 metric tons annually – about 40 % of all the pasta consumed in the country. By getting both electricity and heat from the natural gas it purchases, the company benefits from savings on both forms of energy while solving its voltage stability problems and reducing total emissions. The company estimates that it has reduced its electricity purchases by 60% and its fossil fuel purchases by 70%, resulting in savings of approximately 50 000 USD per month on its energy bills.

The heart of the cogeneration system is a 1750 kW gas engine generator set from Cummins.

Approximately 3.4 million Btu/h of heat is recovered from the generator set’s exhaust system to be used for food processing and pasta drying.

Lean burn

The CHP system consists of a natural-gas-powered reciprocating engine generator set, an exhaust gas heat exchanger, switchgear and controls. The key component is a lean-burn 1750 kW Cummins natural gas fired generator set. The genset operates 24 hours a day in parallel with the local utility in order to stabilise the voltage of the utility power coming into the facility and to replace a significant portion of the power the company purchases. Should the utility fail for any reason, the CHP system would continue to operate, providing up to 1750 kWe to run various plant operations.

Compact in size for its power output, the generator set installed at Pastas Doria has proven to be very durable, fuel efficient and clean burning in numerous installations around the world. Since fuel costs make up the major cost of ownership over the CHP system’s useful life, the engine’s efficiency plays a large role in reducing operating costs. The Cummins engine is also, says its maker, one of the cleanest natural gas engines available, with extremely low emissions of nitrogen oxides and carbon monoxide.

“Pastas Doria selected Cummins Power Generation based on our technical knowledge and a long history of working together,” says Luz Patricia Ochoa, managing director of Ingenergia, the energy solutions business partner for this contract. “Other businesses within Pastas Doria’s corporate group have installed a number of our standby power systems. We were able to offer the highest quality of heat energy for their processes.”

Waste heat from the genset’s exhaust is used to provide 3.4 million Btu/h of heat energy to the plant’s boilers, pasta-drying operations and space heating, which offsets fuel oil purchases. The 91 litre, 18 cylinder, spark-ignited lean-burn natural gas engine has proved to be very suitable for CHP applications owing to the high specific heat of the engine’s exhaust gas. The heat exchanger can be designed to produce low-pressure steam, hot water or hot air as the application demands.

Other advantages

Pastas Doria has found that the CHP system offers other advantages besides cost savings. “The system offers novel technology that allows industrialists new competitive advantages,” says Guillermo Botero Oviedo, supply chain manager for Pastas Doria. “In our case, the results have been good and have met our expectations for reliability, savings and efficiency.”

In addition, the company’s experience with support from Cummins during the implementation of the CHP system was very positive. “The supplier’s technical support was critical – from preliminary engineering and systems design through to system implementation. Meeting the quality standards for layout and subsequent installation are key requirements for a food manufacturing plant” Oviedo says.

Co-ordinated maintenance

Since both the production facility and the CHP system run 24 hours a day, Pastas Doria has been able to schedule generator set maintenance at the same time the plant is shut down for routine maintenance. Once a month, the generator is taken offline for about four hours. During that time, plant personnel inspect the generator set and do routine cleaning and maintenance. After every 1500 hours of operation, or two months, they adjust the valves, change the oil and replace the spark plugs, oil filters and air filters. Since plant maintenance and generator set maintenance occur at the same time every month, there is no disruption in production, with the result that Pastas Doria can manufacture its food products with higher productivity and lower cost than in the past.