Abstract on Cogeneration System at St. Lucia Distillers
by Richard Gunpat, B.Sc. (Mech. Eng)
This paper is on the addition of a single stage back pressure turbine to an existing distillery that uses low pressure steam, but generates it at a higher pressure. The main concern in this project is matching the electrical demand with the process demand, while not being connected to the electrical grid whatsoever (stand alone system).
A steam turbine was incorporated by retrofitting the steam mains and directing it to the turbine, thereby producing rotational energy resulting in electrical energy being generated. The steam is then transmitted to process (low pressure steam).
This project was attractive as there was an existing source of continuous steam supply; fuel costs are minimal and the cost of electricity is relatively high. This makes cogeneration ideal in this application.
Waste oil from ships was the main fuel used in the boilers. It is obtained at virtually no cost; else the ships would have to pay to dispose of it. It is treated before being burnt in the boiler to remove water content and other impurities that may affect combustion. Here is a classic example where a company is making use of available source of fuel which would otherwise be disposed of and contaminate the earth.