scholarly journals The influence of urea on the K2CO3 and NH4VO3 solubility in the K2CO3 + NH4VO3 + H2O system

2008 ◽  
Vol 10 (4) ◽  
pp. 25-27
Author(s):  
Urszula Kiełkowska
Keyword(s):  
Density Dependence ◽  
Production Process ◽  
Potassium Carbonate ◽  
Potassium Ion ◽  
Operating Conditions ◽  
Optimum Operating ◽  
New Production ◽  
Ion Concentrations ◽  
Solution Density ◽  
Dependence Versus

The influence of urea on the K2CO3 and NH4VO3 solubility in the K2CO3 + NH4VO3 + H2O system The influence of urea on the vanadium(V) and potassium ion concentrations in the K2CO3 + NH4VO3 + H2O system was determined in the temperature range of 293 K to 313 K. Additionally, the solution density dependence versus the urea concentration was presented. These data are essential for the assessment of optimum operating conditions for the new production process of potassium carbonate.

scholarly journals The Influence of Urea on the KHCO3 and NH4VO3 Solubility in the KHCO3 + NH4VO3 + H2O System

2007 ◽  
Vol 9 (2) ◽  
pp. 23-26 ◽  
Author(s):  
Urszula Kiełkowska ◽  
Mieczysław Trypuć ◽  
Krzysztof Mazurek ◽  
Sebastian Drużyński
Keyword(s):  
Density Dependence ◽  
Production Process ◽  
Potassium Carbonate ◽  
Potassium Ion ◽  
Operating Conditions ◽  
Optimum Operating ◽  
New Production ◽  
Ion Concentrations ◽  
Solution Density ◽  
Dependence Versus

The Influence of Urea on the KHCO3 and NH4VO3 Solubility in the KHCO3 + NH4VO3 + H2O System The influence of urea on the vanadium(V) and potassium ion concentrations in the KHCO3 + NH4VO3 + H2O system was determined in the temperature range of 293 K to 303 K. Additionally, the solution density dependence versus the urea concentration was presented. These data are essential for the assessment of optimum operating conditions for the new production process of potassium carbonate.

scholarly journals Kinetic Modeling of Catalytic Olefin Cracking and Methanol-to-Olefins (MTO) over Zeolites: A Review

Catalysts ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 626 ◽  
Author(s):  
Sebastian Standl ◽  
Olaf Hinrichsen
Keyword(s):  
Kinetic Modeling ◽  
Product Distribution ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Reaction Networks ◽  
New Production ◽  
Modeling Methodology ◽  
Steam Cracking ◽  
Increasing Demand ◽  
Future Work

The increasing demand for lower olefins requires new production routes besides steam cracking and fluid catalytic cracking (FCC). Furthermore, less energy consumption, more flexibility in feed and a higher influence on the product distribution are necessary. In this context, catalytic olefin cracking and methanol-to-olefins (MTO) gain in importance. Here, the undesired higher olefins can be catalytically converted and, for methanol, the possibility of a green synthesis route exists. Kinetic modeling of these processes is a helpful tool in understanding the reactivity and finding optimum operating points; however, it is also challenging because reaction networks for hydrocarbon interconversion are rather complex. This review analyzes different deterministic kinetic models published in the literature since 2000. After a presentation of the underlying chemistry and thermodynamics, the models are compared in terms of catalysts, reaction setups and operating conditions. Furthermore, the modeling methodology is shown; both lumped and microkinetic approaches can be found. Despite ZSM-5 being the most widely used catalyst for these processes, other catalysts such as SAPO-34, SAPO-18 and ZSM-23 are also discussed here. Finally, some general as well as reaction-specific recommendations for future work on modeling of complex reaction networks are given.

scholarly journals Enzymatic Transesterification of Waste Frying Oil from Local Restaurants in East Colombia Using a Combined Lipase System

2020 ◽  
Vol 10 (10) ◽  
pp. 3566
Author(s):  
Mary Angélica Ferreira Vela ◽  
Juan C. Acevedo-Páez ◽  
Nestor Urbina-Suárez ◽  
Yeily Adriana Rangel Basto ◽  
Ángel Darío González-Delgado
Keyword(s):  
Reaction Time ◽  
Methyl Esters ◽  
Enzyme Concentration ◽  
Operating Conditions ◽  
Frying Oil ◽  
Biodiesel Production ◽  
Optimum Operating ◽  
Waste Frying Oil ◽  
Production Chain ◽  
Enzymatic Transesterification

The search for innovation and biotechnological strategies in the biodiesel production chain have become a topic of interest for scientific community owing the importance of renewable energy sources. This work aimed to implement an enzymatic transesterification process to obtain biodiesel from waste frying oil (WFO). The transesterification was performed by varying reaction times (8 h, 12 h and 16 h), enzyme concentrations of lipase XX 25 split (14%, 16% and 18%), pH of reaction media (6, 7 and 8) and reaction temperature (35, 38 and 40 °C) with a fixed alcohol–oil molar ratio of 3:1. The optimum operating conditions were selected to quantify the amount of fatty acid methyl esters (FAMEs) generated. The highest biodiesel production was reached with an enzyme concentration of 14%, reaction time of 8 h, pH of 7 and temperature of 38 °C. It was estimated a FAMEs production of 42.86% for the selected experiment; however, best physicochemical characteristics of biodiesel were achieved with an enzyme concentration of 16% and reaction time of 8 h. Results suggested that enzymatic transesterification process was favorable because the amount of methyl esters obtained was similar to the content of fatty acids in the WFO.

Optimum operating conditions for chiral separations in liquid chromatography

The Analyst ◽  
1999 ◽  
Vol 124 (5) ◽  
pp. 713-719 ◽  
Author(s):  
R. P. W. Scott ◽  
Thomas E. Beesley
Keyword(s):  
Liquid Chromatography ◽  
Chiral Separations ◽  
Operating Conditions ◽  
Optimum Operating

Performance Analysis of a Variable Speed-Ratio Metal V-Belt Drive

1988 ◽  
Vol 110 (4) ◽  
pp. 472-481 ◽  
Author(s):  
D. C. Sun
Keyword(s):  
Operating Conditions ◽  
Computational Scheme ◽  
Optimum Operating ◽  
Speed Ratio ◽  
Belt Drive ◽  
Variable Speed ◽  
Change Effect ◽  
Multiple Band ◽  
Ratio Change ◽  
Metal Block

A model of the metal V-belt drive (MBD), considering its detailed multiple-band and metal-block structure, and the ratio-change effect during its operation, is constructed and analyzed. A computational scheme is devised that adapts the analysis to the computation of the MBD’s performance for any specified drive-schedule. General performance characteristics of the MBD and an example illustrating its response to a given drive-schedule are presented. The use of the analysis and the computational scheme in the design of the MBD and in finding the optimum operating conditions is discussed.

Removal of Dyes from Aqueous Solutions by Adsorption on Chrome-Tanned Solid Wastes Generated in the Leather Industry

2003 ◽  
Vol 38 (2) ◽  
pp. 393-411 ◽  
Author(s):  
Soufiane Tahiri ◽  
Ali Messaoudi ◽  
Abderrahman Albizane ◽  
Mohamed Azzi ◽  
Mohamed Bouhria ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Operating Conditions ◽  
Solid Wastes ◽  
Cationic Dyes ◽  
Optimum Operating ◽  
Leather Industry ◽  
Anionic Dyes ◽  
Ph Values ◽  
Acidic Conditions ◽  
Dyes Adsorption

Abstract In this work, the ability of chrome shavings and of crust leather buffing dusts to remove dyes from aqueous solutions has been studied. Buffing dusts proved to be a much better adsorbent than chrome shavings for cationic dyes. The adsorption of anionic dyes is very important on two studied wastes. The pH has an obvious influence on the adsorption of dyes. Adsorption of cationic dyes is less favourable under acidic conditions (pH <3.5) and at high pH values (pH >10.5). The adsorption of anionic dyes on both adsorbents is more favourable under acidic conditions (pH <3). The adsorption on chrome shavings is improved by the use of finer particles. The kinetic adsorption was also studied. Adsorption isotherms, at the optimum operating conditions, were determined. Adsorption follows the Langmuir model. The isotherm parameters have been calculated. The column technique could be applied to treat significant volumes of solutions.

scholarly journals Modification of Cassava Starch Using Lactic Acid Hydrolysis in The Rotary-UV Dryer to Improve Physichocemical Properties

2018 ◽  
Vol 156 ◽  
pp. 01018 ◽  
Author(s):  
Siswo Sumardiono ◽  
Bakti Jos ◽  
Denny Firmansyah ◽  
Rahmi Hidayatunajah ◽  
Isti Pudjihastuti
Keyword(s):  
Lactic Acid ◽  
Acid Hydrolysis ◽  
Wheat Flour ◽  
Uv Light ◽  
Import Substitution ◽  
Cassava Starch ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Modified Starch ◽  
Significant Difference

Food security should be supported in an effort to utilize local products into import substitution products. Cassava starch has the potential to be developed into semi-finished products in the form of flour or starch which does not contain gluten but can inflate large baking process, potentially as a substitute for wheat flour-the main ingredient for making bread. The characteristic of the starch is influenced by the type of starch composition and structure. Natural starch has physicochemical properties i.e. a long time cooking and pasta formed hard. These constraints allow us to modify cassava starch by a combination of lactic acid hydrolysis and drying with rotary UV system. Modified cassava starch is expected to be used as a substitute for wheat flour. The aim of the research which is a combination of lactic acid hydrolysis and drying using a rotary UV system is to examine the optimum operating conditions in the drying process of starch hydrolysis with parameter the physicochemical and rheological properties of modified cassava starch. The initial process study is to hydrolyze cassava starch using lactic acid. Furthermore, hydrolyzed cassava starch is then dried using UV light in the rotary dryers system. There are a variety of changing variables, i.e. time of irradiation cassava starch-lactic acid hydrolysis products in the rotary UV light and air drying temperature. The research results show that modified starch has a better characteristic than the natural starch. From the analysis, the best point of swelling power, solubility and baking expansion is consequently 15.62 g/g; 24.19 %; 2.21 ml/gr. The FTIR result shows that there is no significant difference of the chemical structure because the starch modification only change the physical characteristics. From the SEM analysis, we can know that the size of the starch’s granule changes between the natural starch and the modified starch..

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