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development would have been in a better sense of proportion, more harmonious, more in line with sound economic maxims, and less hysterical and passionate than under the jerk of a world catastrophe.” In the midst of this great activity Doctor Prochazka found time to support our chemical societies. He is one of the earliest SOCIETY,his membership members of the AMERICANCHEMICAL dating from 1877. He became an officer of the SOCIETYand helped the good cause along by papers and abstracts. He early became a member of the American Institute of Chemical Engineers and frequently attended its meeting, often accompanied by Mrs. Prochazka, their daughter Ottilie, and son George. Doctor Prochazka’s talents do not all center in science, tech-
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nology, and business. He is a great lover of music, is a capable pianist, and an enthusiastic attendant a t the opera. Since his retirement he has spent much of his time in Europe where he can enjoy the musical masterpieces as rendered by the greatest of living artists. He is greatly interested in theology and Biblicd history. Doctor Prochazka’s friends enjoy his company on account of his keen and subtle wit and sharp retorts. His active restless mind analyzes as quickly and surely as ever, every problem submitted to him. Those who know him can readily understand why he succeeded so well in solving the highly complex problems -political, technical, and economic-of the dye industry. J. C. OLSEN
CORRESPONDENCE Comparative Efficiencies of Amylo and -Malt Processes for Production of Industrial Alcohol SIR: I n a recent article Owen (2) explained the special advantages of the Amylo process in the production of industrial alcohol from grain. This process is particularly applicable in tropical climates. Its advantages are given by Owen as (1) economy due to saving in malt, (2) decreases in losses due to infection introduced with the malt, (3) increased yields of alcohol, and (4)higher purity of alcohol formed in the mash. Of these only the third has practical importance. Foth (1) gives the following figures: GRAIN
Y I ~ L OF D ALCOHOL AMOUNT Amylo process Malt process Kg. Liters Liters 100 39.60 ... 90 38.28 39.07
Maize Maize Barley” Used as malt in Amylo proce8a.
]
a
The difference in alcohol production (1.32 liters) and in price of raw materials is in favor of the Amylo process. An important feature is the energy consumption for production of alcohol from various raw materials. An efficient large factory would require for the production of 100 liters of alcohol, on the average, 100 kg. of saccharine raw materials, 130 kg. of amylaceous raw materials by the malt process, and 230 kg. of amylaceous raw materials by the Amylo process. The power consumption in the Amylo process greatly exceeds that in the malt process. Moreover, the Amylo distillery must have a complete bacteriological laboratory and larger expert personnel to propagate bubs, yeast, and mold, which are costly in the installation of new factories. The higher yield of alcohol by the Amylo process is offset by the higher consumption of energy and special installations which are not necessary in factories operating with malt. Using the Amylo process and operating with double converters (dampers), the sterilizing and boiling of mash require more steam. Conditions in the secondary working plant are important. With the Amylo process there is no need for a special saccharification vat with stirring apparatus or pump to deliver saccharified mash to the fermenting tanks, but on the other hand a stirring apparatus and an air compressor must operate over long periods for every tank. Because of steam consumption, this difference is greater in small factories than in large. A small distillery operating with
potatoes will consume 140 kg. of coal for each 100 liters of wine spirits produced, if the daily production is 100 liters. The same distillery will use only 90 kg. of coal for 100 liters of alcohol if the daily production increases to 1000 liters. The Amylo process is applicable only in large-scale operating works where converters and fermenters, with 100,000 liters the minimum capacity, are connected in series, and superfluous steam escaping from one may be used in the next. As an example, two distilleries in Syria may be mentioned. These use durrha (white maize) as raw material. The first factory has a daily production of 2500 liters and, operating with the malt process and open vats, produces 37.5 liters of wine spirits from 100 kg. of grain. The other with a daily production of 3500 liters, using the Amylo process produces about 40 liters from 100 kg. of grain. This efficiency was largely offset by the difference in coal consumption which in the first factory was 140 kg. per 100 liters of alcohol produced, compared with 300 kg. in the second. The Boulard process mentioned by Owen is a great improvement in the Amylo process, but is not yet perfected. The mold Mucor Boulard No. 5 develops volatile acids (acetic acid), and yields are lower than with the regular Amylo process. The temperature of saccharification and fermentation (35” to 38” C.) is suitable for tropical climates, but presents problems in cooler climates, where fermentation is generally carried out. With these difficulties eliminated, the Boulard process probably is more efficient than the malt process. LITERATURE CITED (1) Foth, G.. “Handbuch der Spiritus Fabrikation,” Paul Parey, Berlin, 1929. (2) Owen, W. L., IND. Eso. CHEW.25, 87 (1933). PAULAY EDE u. 57 BUDAPEST, HUNQARY March 1, 1933
M. NEUBAUER
Amylo Process and Its Improvement SIR: The substitution of the Amylo process for the malt process in the manufacturing of grain alcohol in warm countries not only solves the economic problem, but also the important question of adaptation to climatic conditions [Owen, IND.ENQ. CHEM.,25, 87 (1933) I. The work of Boidin and of his collaborators have brought the process to a high degree of perfection, which combines simplicity of application with maximum dependability. In the bacterio-
