scholarly journals TECHNOLOGY OF CYCLIC DISTILLATION IN ALCOHOL PRODUCTION

2019 ◽  
Vol 13 (4) ◽  
Author(s):  
Y. Buliy ◽  
P. Shiyan ◽  
A. Kuts ◽  
I. Melnik
Keyword(s):  
Mass Transfer ◽  
Impurity Concentration ◽  
Steam Pressure ◽  
Hydrodynamic Mode ◽  
Specific Flow ◽  
Vapor Velocity ◽  
Alcohol Production ◽  
Cyclic Mode ◽  
Fusel Alcohols ◽  
Heating Steam

Alternate changing of the steaming periods and liquid overflow allows to intensify mass transfer between liquid and steam and to reduce the specific consumption of heating steam in the process of separation of multicomponent mixtures. Known methods and models have not found widespread practical use due to the lack of mass transfer in the steam period, fluctuations in steam pressure in the collector, the complexity of constructive solutions to ensure cyclic mode, etc. The authors propose a technology for rectification, which involves the cyclic motion of the liquid without interrupting of the supply of heating steam and the construction of a rectification column for its implementation. The purpose of the work was to research the effectiveness of the proposed technology in the process of rectification of alcohol-containing fractions and to establish the specific flow rate of steam in the impurity concentration column. To ensure a cyclic mode, the column was equipped with movable liquid transfer devices connected to actuating mechanismes, which acted according to the controller program, and perforated (scale-shaped) trays. The primary task was to determine the hydrodynamic mode of operation of the contact devices - the lower and upper the critical vapor velocity of at which the liquid is retained on the plates and there is its entrainment. It is established that the vapor velocity in the free section of the column can reach 1.2 m/s or more, and in the openings of the scales must exceed the first critical velocity of 6.5-7.5 m/s. The weeping of the tray occurs at the vapor velocity in the holes of 1.5-1 m/s. The investigations were carried out in the production conditions of the Chudniv branch of SE “Zhytomyr liquor producer ”. It is experimentally proved that in the process of rectification of alcohol-containing fractions, the main impurities are removed completely, the degree of extraction of higher fusel alcohols is increased by 38%, methanol - by 15.6 %, the multiplicity of concentration of the main impurities is increased by 25 %, the higher alcohols - by 40 %, methanol – by 34 %, acrolein – by 36 %. The costs of heating steam are reduced by 30 % compared to typical installations and do not exceed 13 kg/dal of absolute alcohol introduced with feed. Exempted from the key impurities the bottom liquid of the impurity concentration column should be used for hydroselection in the purifying column.

scholarly journals Application of a Two-Stage Steam Jet Injector Unit for Latent Heat Recovery of a Marine Steam Turbine Propulsion Plant

2021 ◽  
Vol 11 (12) ◽  
pp. 5511
Author(s):  
Szymon Grzesiak ◽  
Andrzej Adamkiewicz
Keyword(s):  
Steam Turbine ◽  
Steam Pressure ◽  
Relative Increase ◽  
Parameters Optimization ◽  
Feed Water ◽  
Water Heating ◽  
Two Stage ◽  
Heating Systems ◽  
Heating Steam ◽  
Numerical Research

The paper presents the results of the numerical research of the steam jet injector applications for the regenerative feed water heating systems of marine steam turbine propulsion plants. The analysis shows that the use of a single injector for a single heat exchanger results in a relative increase in the thermal efficiency of the plant by 0.6–0.9%. The analysis also indicates the legitimacy of the usage of multistage feed water heating systems, which would enable the operating parameters optimization of the injectors. The obtained steam pressure up to the value of 1.8 barA allows for the heating of the feed water up to 110 °C. For higher degrees of feed water heating in the heat exchangers, it is necessary to supply heating steam of higher pressure. Therefore, the usage of two-stage steam jet injector units was considered advisable for the analyses.

Studying the Effect of Fuel Elements Structural Materials Corrosion on their Operating Life

2021 ◽  
Vol 1038 ◽  
pp. 108-115
Author(s):  
Yuliana Hapon ◽  
Maksym Kustov ◽  
Volodumur Kalugin ◽  
Alexander Savchenko
Keyword(s):  
Experimental Data ◽  
Mass Transfer ◽  
Fuel Element ◽  
State Level ◽  
External Factors ◽  
Economic Losses ◽  
Operating Life ◽  
Hydrodynamic Mode ◽  
Internal And External Factors ◽  
Fuel Elements

The paper deals with experimental data regarding the effect of internal and external factors on the corrosion decay of Zr1Nb alloy fuel elements. Based on the analysis results, losses of zirconium that transfers to oxide or coolant as per the fuel element wall weight and thickness as well as economic losses from their corrosion decay have been theoretically calculated. To avoid a state-level emergency occurrence, an increase in the fuel element wall thickness up to 660 μm is proposed, which can increase the operating life under the conditions of trouble-free coolant mass transfer hydrodynamic mode.

scholarly journals Improving the massecuite crystallization in sugar production

2021 ◽  
Vol 83 (1) ◽  
pp. 86-93
Author(s):  
N. G. Kulneva ◽  
V. A. Fedoruk ◽  
N. A. Matvienko ◽  
E. M. Ponomareva
Keyword(s):  
Operating Mode ◽  
Steam Pressure ◽  
Small Temperature ◽  
Steam Consumption ◽  
Heating Chamber ◽  
Heating Steam ◽  
Vacuum Apparatus ◽  
Continuous Vacuum ◽  
Product Department ◽  
Entire Apparatus

The article discusses the concepts of continuous vacuum apparatus operation: vertical VKT (VKT – Verdampfungs-Kristallisations-Turm) and horizontal cascade of VKH vacuum apparatus (VKH —horizontal vacuum pan) from BMA (Germany). The advantages and features of the vertical continuous vacuum apparatus VKT are shown, as well as the possibilities for increasing the efficiency of the product department of sugar factories. Thanks to the special design of the crystallization chambers, the low massecuite level above the heating chamber and the use of mechanical stirrers in each chamber, the VKT apparatus can operate without difficulty with a very small temperature difference between heating steam and massecuite, as well as with an absolute heating steam pressure well below 1 bar. With optimal use of VKT vacuum apparatus, a variety of energy-saving schemes can be implemented, for example, double-effect evaporation in the crystallization section. Part of the secondary crystallization steam is used to heat one of the VKT units, which saves the heating steam of the evaporator unit used for this purpose. With an increase in the productivity of the sugar factory, it is possible to quickly equip the VKT apparatus with an additional chamber. The device works continuously throughout the season, especially with products with massecuite purity of more than 94%. The chambers are cleaned without stopping the entire apparatus. The boiling of massecuite of all stages of crystallization in VKT devices ensures a uniform operating mode of the food compartment, allows to achieve an increase in sugar yield and helps to reduce steam consumption at the plant.

Pyruvate Decarboxylase Catalyzes Decarboxylation of Branched-Chain 2-Oxo Acids but Is Not Essential for Fusel Alcohol Production by Saccharomyces cerevisiae

1998 ◽  
Vol 64 (4) ◽  
pp. 1303-1307 ◽  
Author(s):  
Eelko G. ter Schure ◽  
Marcel T. Flikweert ◽  
Johannes P. van Dijken ◽  
Jack T. Pronk ◽  
C. Theo Verrips
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Alcohol Dehydrogenase ◽  
Pyruvate Decarboxylase ◽  
Wild Type ◽  
Alcohol Production ◽  
Whole Cells ◽  
Fusel Alcohols ◽  
Cell Extracts ◽  
Fusel Alcohol ◽  
Branched Chain

ABSTRACT The fusel alcohols 3-methyl-1-butanol, 2-methyl-1-butanol, and 2-methyl-propanol are important flavor compounds in yeast-derived food products and beverages. The formation of these compounds from branched-chain amino acids is generally assumed to occur via the Ehrlich pathway, which involves the concerted action of a branched-chain transaminase, a decarboxylase, and an alcohol dehydrogenase. Partially purified preparations of pyruvate decarboxylase (EC 4.1.1.1 ) have been reported to catalyze the decarboxylation of the branched-chain 2-oxo acids formed upon transamination of leucine, isoleucine, and valine. Indeed, in a coupled enzymatic assay with horse liver alcohol dehydrogenase, cell extracts of a wild-type Saccharomyces cerevisiae strain exhibited significant decarboxylation rates with these branched-chain 2-oxo acids. Decarboxylation of branched-chain 2-oxo acids was not detectable in cell extracts of an isogenic strain in which all threePDC genes had been disrupted. Experiments with cell extracts from S. cerevisiae mutants expressing a singlePDC gene demonstrated that both PDC1- andPDC5-encoded isoenzymes can decarboxylate branched-chain 2-oxo acids. To investigate whether pyruvate decarboxylase is essential for fusel alcohol production by whole cells, wild-type S. cerevisiae and an isogenic pyruvate decarboxylase-negative strain were grown on ethanol with a mixture of leucine, isoleucine, and valine as the nitrogen source. Surprisingly, the three corresponding fusel alcohols were produced in both strains. This result proves that decarboxylation of branched-chain 2-oxo acids via pyruvate decarboxylase is not an essential step in fusel alcohol production.

scholarly journals Experimental research of mass transfer in a stabilized foam layer

ScienceRise ◽  
2021 ◽  
pp. 14-22
Author(s):  
Viktor Moiseev ◽  
Eugenia Manoilo ◽  
Oleg Khukhryanskiy ◽  
Kalif Repko
Keyword(s):  
Mass Transfer ◽  
Cross Section ◽  
Contact Element ◽  
Gas Content ◽  
Foam Layer ◽  
Gas Velocity ◽  
Hydrodynamic Mode ◽  
Gas Emissions ◽  
Technological Processes ◽  
Technological Product

The object of research: mass transfer processes on a combined contact element in a column apparatus. Investigated problem: determination of the regularities of process parameters in the processing of gas-liquid systems in a foam layer, as well as to interpret the obtained experimental data. The problem of processing industrial gas flows is solved by conducting the process in an intensive mode. The main scientific results: as a result of the study, the regularities of ammonia absorption were revealed depending on the main parameters of the experiment: gas velocity in the column cross-section, ammonia concentration, free cross-section of the combined contact element, and liquid loads. The process of mass transfer in the gas phase is significantly influenced by hydrodynamic parameters – the gas velocity in the apparatus and the specific load on the liquid, which indirectly affect the height of the liquid layer on the plate and the gas content of the layer. The area of practical use of the research results: sorption processes for processing gases and liquids in technological processes, absorption of harmful substances in the treatment of gas emissions. Innovative technological product: new block poppet-nozzle contact device that operates in a stabilized hydrodynamic mode; new ball-shaped weighted nozzle for three-phase foam layer. Scope of application the innovative technological product: technological processes in the treatment of gas emissions or technological gases.

scholarly journals Isolation and characterization of yeast for the production of rice wine with low fusel alcohol content

PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0260024
Author(s):  
Huawei Yuan ◽  
Wenhao Chen ◽  
Yuanlin Chen ◽  
Lian Wang ◽  
Chao Zhang ◽  
...  
Keyword(s):  
Isoamyl Alcohol ◽  
Rice Wine ◽  
Wine Production ◽  
Flavor Compound ◽  
Suitable Candidate ◽  
Alcohol Production ◽  
Isolation And Characterization ◽  
Fusel Alcohols ◽  
Yeast Strains

Fusel alcohols (FAs) are a type of flavor compound found in rice wine. An overly high FA content not only leads to spicy, bitter, and astringent taste but also has side effects. Therefore, screening for yeast that produce low FA contents has attracted much attention. Thirty-two yeast strains were isolated from fermenting material during Luzhou-flavor liquor production in this study. Strain YB-12 was selected as a suitable candidate for rice wine production. The strain was identified as a member of the genus Meyerozyma based on phylogenetic analysis using 26S rDNA gene sequences. The ability of strain YB-12 to produce ethanol was similar to that of Saccharomyces cerevisiae NRRL Y-567, while isobutanol and isoamyl alcohol production was only 53.96% and 50.23%, respectively, of that of NRRL Y-567. The FA yield of rice wine produced with strain YB-12 was reduced to 51.85% in a 20 L fermenter. These results demonstrate that strain YB-12 presents promising characteristics for use in the production of rice wine with a potentially low content of FAs.

Evaporation performance: present and future in Colombian cane sugar factories

2017 ◽  
pp. 264-269
Author(s):  
D.F. Cobo ◽  
J.G. Rodriguez ◽  
A.F. Ospina ◽  
A.L. Gomez ◽  
N.J. Gil
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Performance Index ◽  
Steam Pressure ◽  
Cane Sugar ◽  
Heat Transfer Area ◽  
Improve Performance ◽  
Heating Steam ◽  
New Guidelines

Evaporation performance is usually affected by internal and external factors such as sugarcane quality, juice conditioning, exhaust steam availability, juice flow variation, heat transfer area available, type of evaporator, and geometric relationships. These factors influence the evaporation rate and cleaning frequency. An integral strategy to improve performance was proposed, including technological changes (falling-film evaporators) evaluated by simulation, on-line performance index (evaporation performance index, EPI), and new guidelines for the evaporation station configuration. EPI, proposed by Cenicaña (Colombia), is defined as the product of RDS (refractometric dry substance content) difference and juice flow divided by the product of heating steam pressure and heat transfer area. The results show that it is possible to improve performance of the third effects by extending the calandria tubes in Robert-type evaporators; this improves the heat transfer coefficient by 15–30%. In most cases, increasing juice flow velocity in evaporator tubes will increase the overall heat transfer coefficient. The use of longer tubes should be considered when modifications in evaporation stations are required. In addition, the application of EPI as a tool to assess the performance in the evaporation train and make decisions regarding the cleaning schedule was validated.

scholarly journals Substrate Specificity of Thiamine Pyrophosphate-Dependent 2-Oxo-Acid Decarboxylases in Saccharomyces cerevisiae

2012 ◽  
Vol 78 (21) ◽  
pp. 7538-7548 ◽  
Author(s):  
Gabriele Romagnoli ◽  
Marijke A. H. Luttik ◽  
Peter Kötter ◽  
Jack T. Pronk ◽  
Jean-Marc Daran
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Substrate Specificity ◽  
Thiamine Pyrophosphate ◽  
Content Type ◽  
Alcohol Production ◽  
Fusel Alcohols ◽  
Cell Extracts ◽  
Fusel Alcohol ◽  
Branched Chain ◽  
Sulfur Containing

ABSTRACTFusel alcohols are precursors and contributors to flavor and aroma compounds in fermented beverages, and some are under investigation as biofuels. The decarboxylation of 2-oxo acids is a key step in the Ehrlich pathway for fusel alcohol production. InSaccharomyces cerevisiae, five genes share sequence similarity with genes encoding thiamine pyrophosphate-dependent 2-oxo-acid decarboxylases (2ODCs).PDC1,PDC5, andPDC6encode differentially regulated pyruvate decarboxylase isoenzymes;ARO10encodes a 2-oxo-acid decarboxylase with broad substrate specificity, andTHI3has not yet been shown to encode an active decarboxylase. Despite the importance of fusel alcohol production inS. cerevisiae, the substrate specificities of these five 2ODCs have not been systematically compared. When the five 2ODCs were individually overexpressed in apdc1Δpdc5Δpdc6Δaro10Δthi3Δ strain, only Pdc1, Pdc5, and Pdc6 catalyzed the decarboxylation of the linear-chain 2-oxo acids pyruvate, 2-oxo-butanoate, and 2-oxo-pentanoate in cell extracts. The presence of a Pdc isoenzyme was also required for the production ofn-propanol andn-butanol in cultures grown on threonine and norvaline, respectively, as nitrogen sources. These results demonstrate the importance of pyruvate decarboxylases in the natural production ofn-propanol andn-butanol byS. cerevisiae. No decarboxylation activity was found for Thi3 with any of the substrates tested. Only Aro10 and Pdc5 catalyzed the decarboxylation of the aromatic substrate phenylpyruvate, with Aro10 showing superior kinetic properties. Aro10, Pdc1, Pdc5, and Pdc6 exhibited activity with all branched-chain and sulfur-containing 2-oxo acids tested but with markedly different decarboxylation kinetics. The high affinity of Aro10 identified it as a key contributor to the production of branched-chain and sulfur-containing fusel alcohols.

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