Alcohol Distillation

E-117

Purdue University
Cooperative Extension Service
West Lafayette, IN 47907

ALCOHOL DISTILLATION: BASIC PRINCIPLES, EQUIPMENT, PERFORMANCE RELATIONSHIPS, AND SAFETY

Eric Kvaalen, Doctoral Student in Chemical Engineering
Philip C. Wankat, Professor of Chemical Engineering
Bruce A. McKenzie, Extension Agricultural Engineer,
Purdue University

The purpose of this publication is to help you understand the distillation of ethyl alcohol.

It first presents the basic principles involved in distillation and how the process works.

The types of distillation equipment and systems that might be involved in a small fuel alcohol plant are then discussed, as are the performance and control criteria needed for a general evaluation of each.

The publication concludes with a discussion of safety, along with some general selection, operation and management criteria useful in evaluating alternatives.

The information presented here hopefully will help you decide if you want to get into alcohol production, and if so, will help you evaluate the different options that are available to you.

We will only cover those distillation processes and equipment capable of producing alcohol concentrations up to about 95.6 weight percent (wet basis).

Remember, this publication is not a design manual.

Rather its goal is to give a general understanding of distillation processes and the performance of various equipment options in order to aid you in evaluating alcohol production proposals and give a basis for more detailed self-study.

We will not discuss fermentation processes and equipment, or uses of the finished alcohol concentrate.

Ethyl Alcohol

ETHYL ALCOHOL - A VIABLE ALTERNATIVE FUEL

The idea of ethyl alcohol as a liquid fuel is not new. It received considerable discussion and publicity in the 1920's and 1930's as a motor fuel.
It was used as a fuel in several countries during World War II.
Interest surfaced again in the U.S. in the mid 1970's, with the advent of the oil embargo and cartel and the rapidly escalating oil prices that resulted.
At the time of these rapid oil price increases, many people, particularly in the farming community, began to look seriously at ethyl alcohol and gasoline/alcohol blends as alternative fuels. However, by the early 1980's, increased U.S. oil production plus a significant drop in oil consumption due to high prices brought a corresponding world oversupply of oil and a marked drop in oil and gasoline prices.
As a result, interest in alcohol fuels diminished sharply. Interestingly, the increased use of unleaded fuels and subsidies for fuels using 10 percent alcohol caused many oil companies to add ethyl alcohol to their gasoline as a non-lead octane improvement additive.
- Such fuels are not normally advertised as gasoline/alcohol blends.
If one accepts, however, that the long range price of oil and energy will continue to increase, then ethyl alcohol as a liquid fuel, especially for internal combustion spark ignition engines, will continue to be a potentially viable alternative fuel source. The fact that alcohol may be profitably manufactured from a variety of crop and forest residues, as well as from grains themselves, enhances its appeal to farm producers.