DESCRIPTION

Technical Description

As well as its great importance for the chemical and foodstuffs industries, ethanol (alcohol) is increasingly used as a fuel. The CE 640 can be used to conduct realistic experiments for the production of ethanol from starch-based raw materials such as potatoes. The experimental plant consists of three main components: a mash tank, a fermentation tank and a distillation unit.

A mixture of water, finely chopped potatoes and alpha-amylase (enzyme) is filled into the mash tank. To dissolve the tightly packed starch chains in the potatoes, heating steam is injected into the mixture via a nozzle (gelatinisation). This increases the flow resistance of the mash, which would prevent further processes. The alpha-amylase breaks up the starch chains (liquefying) thereby reducing the flow resistance. Gluco-amylase is used to convert the starch into sugar (saccharification). This enzyme requires lower temperatures and pH values. The temperature is reduced using the water cooling jacket around the mash tank, the pH value is adjusted by the addition of acid and caustic. After saccharification the mash is pumped into the fermentation tank. During the fermentation process in this tank, ethanol is produced. A water cooling system controls the temperature. After the fermentation process, the mash is pumped into the distillation unit. This is equipped with a bubble cap tray column for separation of the ethanol. Two tanks are available, one for the spent mash, the other for the distilled ethanol.

The experimental plant has comprehensive measurement, control and operating functions, which are controlled via a PLC. A touch screen displays measured values and permits the operation of the system.The steam supply occurs via laboratory network or an optionally available electrical steam generator (CE 715.01).

The well-structured instructional material sets out the fundamentals and provides a step-by-step guide through the experiments.

Learning Objectives / Experiments

- familiarization with the necessary individual steps and system components for production of ethanol:
  * gelatinisation by steam injection
  * liquefaction by use of alpha-amylase
  * saccharification by use of gluco-amylase
  * fermentation: conversion of sugar into ethanol by yeast cultures under anaerobic conditions
  * distillation: separation of ethanol from the mash