Plants of Polygeneration Based on Sugar Cane
Publicación:
Revista Palmas; Vol. 31 Núm. especial, (2010); 88-101
0121-2923
Revista Palmas; Vol. 31 Núm. especial, (2010); 88-101
0121-2923
Abstract
Over the last 500 years, the Brazilian sugarcane industry has evolved from a single product supplier (sugar producer) to an energy production enterprise (sugar, alcohol and electricity). Different technological paths were developed in order to improve the energy conversion processes inside the mill. Those improvements led mills to, first become self-sufficient in energy, and then, sell electricity to the grid. The engineers designed typical steambased cogeneration systems using bagasse to produce the steam and electricity required by the sugar and alcohol production processes. Today, the sugar mill is a polygeneration plant that uses sugarcane to produce sugar, alcohol and electricity and, additionally, generates many by-products (wastes, vinasse, fiber, cakes, etc.), which in most cases are discarded or used inefficiently. This paper presents the technologies currently used by sugar mills, and compares them with the new ones that use energy sources and process by-products in a more rational manner. The purpose of these technologies is to convert these low-value by-products into new value-added ones. Most notable among these technologies are: more efficient steam cycles (like high pressure systems and supercritical pressure steam systems) and combined biomass cycles based on gasification. Furthermore, it addresses the renewability of processes based on an exergy index of renewability En los últimos 500 años la industria azucarera de Brasil ha evolucionado pasó de la simple producción de azúcar a convertirse en una empresa de producción de energía (azúcar, alcohol y electricidad). Para mejorar los procesos de conversión de energía dentro del ingenio se desarrollaron diferentes caminos tecnológicos. Esta transformación llevó a los ingenios, en primer lugar, a llegar a ser autosuficientes en energía, y luego, a vender electricidad a la red. Los ingenieros diseñaron sistemas de generación típicos, utilizando bagazo para producir el vapor y la electricidad requeridos para los procesos de producción de azúcar y alcohol. El ingenio es hoy una planta de cogeneración que utiliza caña para producir azúcar, alcohol y electricidad y, además, da origen a muchos subproductos (desechos, vinazas, fibra, torta, etc.), que, en la mayoría de los casos se eliminan o se usan en forma ineficiente. Este documento presenta las tecnologías que emplean actualmente los ingenios azucareros y las compara con las nuevas que utilizan en forma más racional tanto las fuentes de energía como los subproductos de los procesos. El objetivo de este conjunto de técnicas es convertir subproductos de bajo valor en nuevos productos con valor agregado. Las más conocidas son ciclos de vapor más eficientes (como sistemas de alta presión y presión supercrítica de sistemas de compresión de vapor) y ciclos combinados de biomasa basados en gasificación. Adicionalmente, se aborda el tema de la renovabilidad de los procesos con base en un índice de energía de renovabilidad.
Over the last 500 years, the Brazilian sugarcane industry has evolved from a single product supplier (sugar producer) to an energy production enterprise (sugar, alcohol and electricity). Different technological paths were developed in order to improve the energy conversion processes inside the mill. Those improvements led mills to, first become self-sufficient in energy, and then, sell electricity to the grid. The engineers designed typical steambased cogeneration systems using bagasse to produce the steam and electricity required by the sugar and alcohol production processes. Today, the sugar mill is a polygeneration plant that uses sugarcane to produce sugar, alcohol and electricity and, additionally, generates many by-products (wastes, vinasse, fiber, cakes, etc.), which in most cases are discarded or used inefficiently. This paper presents the technologies currently used by sugar mills, and compares them with the new ones that use energy sources and process by-products in a more rational manner. The purpose of these technologies is to convert these low-value by-products into new value-added ones. Most notable among these technologies are: more efficient steam cycles (like high pressure systems and supercritical pressure steam systems) and combined biomass cycles based on gasification. Furthermore, it addresses the renewability of processes based on an exergy index of renewability
Palabras clave:
caña de azúcar
productos vegetales procesados
industria de la caña de azúcar
caña de azúcar
productos vegetales procesados
industria de la caña de azúcar