WO1998058071A1

WO1998058071A1 - The procedure for obtaining ethyl-alcohol from cellulose

Info

Publication number: WO1998058071A1
Application number: PCT/YU1998/000015
Authority: WO
Inventors: Dusan Ciric
Original assignee: Individual
Current assignee: Individual
Priority date: 1997-06-18
Filing date: 1998-06-17
Publication date: 1998-12-23
Anticipated expiration: 1999-12-18
Also published as: YU25697A; AU8075398A

Abstract

The procedure for obtaining ethyl-alcohol from cellulose of annual and perennial plants is described here. The chopped cellulose material is hydrolysed with the acid solution, such as sulphuric acid. The products of hydrolysis are exposed to the base, such as ammonium hydroxide, because of the neutralization of acid (a pH between 6 and 7). Solid and liquid phases are separated and liquid phase containing the sugar solution is being fermented with brewers' yeast, and when fermentation is completed ethyl-alcohol as its final product is distilled to concentration of 96.7 vol. %.

Description

THE PROCEDURE FOR OBTAINING ETHYL-ALCOHOL FROM CELLULOSE

Tehnical Field

This discovery is concerned with the field of obtaining ethyl-alcohol, i.e. ethanol. more specifically with the field of obtaining ethanol from cellulose found in annual plants. According to International Classification of Patents this discovery has further caracteristics:

Tehnical Problem

This discovery solves the problem of obtaining ethyl-alcohol primarily from remnants of annual plants, i.e. from crops such as straw, cornstalks, sunflower stalks, sunflower hulls, etc. by using sulphuric acid. The problem of production of ethanol from soft perennial plants and numerous remnants in the forest production and processing of lumber or in the production and processing of other cellulose products, as paper, but using more sulphuric acid.

Tehnical Situation

O erall survey of professional literature proved that the procedure for obtaining ethyl-alcohol from cellulose was not described, although the procedure for obtaining ethyl-alcohol from starch is well-known. For example, such production is known in Brazil, where ethanol used as fuel is produced because of the favorable conditions from tuber starch of Tapioca plant which achieves enormous height without any help of planting, irrigation and fertilizing. Description of a Solution of the Technical Problem

The novelty of this discovery is that cellulose cuttings such as straw, cornstalks, sunflower stalks, sunflower hulls, etc. have been treated in order to carry out the hydrolysis of 7% (or 9%) sulphuric acid solution in water (mass ratio of cellulose raw materials and sulphuric acid solution is 1 : 1 ). Such procedure of hydrolysis can be carried out under temperatures up to 80° C while the speed of hydrolysis becomes larger with higher temperatures, such reaction is completed within 20 to 24 hours, and without heating it lasts 3 to 4 times longer. After the procedures of hydrolysis, neutralisation and cooling were completed, liquid solution is separated from solid remainings. The liquid solution consists of dissolved glycose with small quantities of sucrose, pentose and hexose wich are then exposed to further chemical treatment consisting of fermentation with brewers' yeast (4-6 kg being used per 1 tone of dissolved sugar) and with a small quantity of germinating barley. The solution of ethanol achieved by previously described fermentation is destilled in columns until the final concentracion is 96,7 vol % and can be used as a fuel.

Solid remainings from hydrolysis consisting of unreacted cellulose with miscellaneous ingredients can be treated with base in order to compost it. or by means of Schwaeizer reagent and thus produce copper ammonia silk.

As already mentioned according to this discovery the main raw materials for production of ethyl-alcohol are the waste materials of crops such as various cereals, corn, sunflower, etc. According to statistical data from 1991 in Yugoslavia there were:

• 5 300 000 t of straw

• 1 1 000 000 t of cornstalks

• 448 000 t of sunflower stalks

• 1 19 000 t of sunflower hulls

As straw contains 39 % of cellulose, cornstalks 30,5 % of cellulose, sunflower stalks 50.7 % of cellulose and sunflower hulls 24-27 % of cellulose, thus in theory the quantity of cellulose for proccessing it into ethyl-alcohol according to this discovery is 5 706 359 t. In practice according to this discovery stated quantity of cellulose achieved the production of 3 290 078 t of 98 % ethyl-alcohol.

As already mentioned, according to this discovery, for production of ethyl- alcohol the perennial plants (as soft wood and various remnants in lumber and forest productions and lumber industry) can be used as well. However, we should have in mind that such raw materials for production of ethyl-alcohol require larger sulphuric acid consumption, comparing with the consumption during the process w ith the waste materials of crops.

Solid raw material should be well chopped into small pieces so that the particles are up to 0,5 mm all, in order to make the procedure run according to this discovery as fast as possible. Such size of the raw material particles offers great surface of reaction when in touch with water and sulphuric acid. As already known, cellulose is chemically polyglucose, which is in the process of hydrolysis, according to this discovery split i.e. chain molecule of cellulose splits under described conditions into small cyclic molecules of glucose, presented in equation as follows:

(C₆H₁₂0₅)n + n H₂0 = n (C₆H,₄0₆)

Obtained glucose is, after separation from solid remainings and after neutralization of acid, exposed to fermentation with brewers' yeast and germinating barley so it converts to ethyl-alcohol according to the following equation:

C₆H,₂0₆ = 2 C₂H₅OH + 2 C0₂

Ethyl-alcohol obtained in this way is brought into the process of destination which is conducted in several numerically connected destination columns, and is completed when ethyl-alcohol reaches 96,7 vol %. It is essential to mention that in achieved solution of ethyl-alcohol beside water there is little wood-alcohol and ethereal oils as contens of raw materials.

In the following description an example of the procedure according to this discovery is presented in details.

Well chopped raw material as straw, cornstalks, sunflower stalks and sunflower hulls (particles up to 0,5 mm) are put into the pool which can be warmed up. In the same pool, the 7 % solution of sulphuric acid is added when strain is in question and 9- 12 % solution of sulphuric acid when others, in order to carry out the hydrolysis phase. Aiming to accelerate the procedure of hydrolysis it is desirable to warm the content in the pool up to temperatures that do not go over 50 °C. Here, we should have in mind that hydrolysis is possible under the lower temperatures (25-35 °C), but is substantially slower comparing with the one under higher temperatures. If the phase of hydrolysis is carried out under about 80 °C, then it will be completed in 20-24 hours, while under temperatures of 25-35 °C it would last 3-4 times longer. After the completed procedure of hydrolysis the whole content of the pool is being cooled and base is added as neutralization of sulphuric acid. Miscellaneous bases can be used for neutralization of acid but it is convenient for this discovery to use ammonium hydroxide in quantities necessary to adjust a pH between 6 and 7. Then, the liquid and solid phases should be separated i.e. separation of sugar and "huskus^". "Huskus" can be used as fertilizer, and solution of sugar is exposed to brewing with the help of brewers' yeast and germinating barley. Brewers^' yeast is added in quantities of 4-6 kg being used per tone of the solution of sugar. Brewing is carried out under temperatures from 20-30 °C and lasts for about 24 hours. When the brewing is completed maximal quantity of ethanol is 62 vol %. In order to increase the concentracion of ethanol, its solution is brought into destination columns and destination is completed when ethanol reaches 96,7 vol %. It is important to mention that "huskus" from the phase hydrolysis may be treated with Schwaeizer reagent in order to get, otherwise expensive copper ammonia silk.

This discovery includes all variations and various ideas can be applied such as use of any material containing cellulose or use of some other acid different from sulphuric acid or use of any base different from ammonium hydroxide.

Claims

PATENT DEMAN D

The procedure for obtaining ethyl-alcohol from cellulose caracterised by chopping straw, cornstalks, sunflower stalks, sunflower hulls and other cellulose material such as wood, wood waste, leaves, paper, etc. in particles up to 0.5 mm and such chopped material being treated with 7- 12 % of acid solution under the temperatures from 25-80 °C (lasting 24-96 hours because of hydrolysis). Then, hydrolysed acid solution being treated with base (a pH between 6 and 7 ). Solid and liquid phases being separated, after which the brewers' yeast is added into liquid phase (4-6 kg being used per tone of solution) lasting for 24 hours under temperature of about 20-30 °C because of conversion of the sugar solution to ethyl-alcohol solution which is further destilled until ethyl-alcohol reaches 96,7 vol %.

2. The procedure according to demand. 1 caracterized by the sulphuric acid being used as an acid in hydrolysis.

3. The procedure according to demands, 1 and 2 characterized by ammonium hydroxide being used for the neutralization of the acid from the phase of hvdrolvsis.

4. The procedure according to demands, 1 -3 characterized by ^"Marc^" from the phase of hydrolysis being used as fertilizer.