Cogeneration potential in Colombian sugar factories

Abstract

Nowadays, the Colombian sugar industry is involved in an expansion process, mainly related to the diversification of final products. In this way, since 2005 five ethanol distilleries have been running, covering just 65% of total ethanol demand. The distilleries were designed coupled with a composting plant, based on vinasses and carbonatation sludge from the sugar factory. Both distilleries and composting plants show many features which make them a special case in the ethanol market, so they produce a maximum of 3 L vinasse/L ethanol. Besides, in all cases, the thermal and electrical power requirements in the ethanol plant are supplied by the sugar factory. In this paper, a brief description of technological features of the typical process configuration followed by the Colombian sugar industry is shown. It comprises the steam consumption distribution by sections, the common configuration of the heat exchanger network (HEN) developed for bleed vapor usage and the role of energy self-sufficiency of the factory played by the bagasse quality. A set of possible scenarios for improving energy efficiency in a selected sugar factory which comprises a modified HEN can be formulated, including a revamping of the existing boiler and finally a new boiler operating at higher pressure. Based on the previous information, the state of the main Colombian cogeneration projects based on sugarcane and its potential impact on the national energy supply is shown. Finally, the paper describes how Colombian governmental requirements for cogeneration plants are trying to establish a legal framework for this novel industrial activity in the country.