scholarly journals Reactive Chromatography Applied to Ethyl Levulinate Synthesis: A Proof of Concept

Processes ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 1684
Author(s):  
Carmelina Rossano ◽  
Claudio Luigi Pizzo ◽  
Riccardo Tesser ◽  
Martino Di Serio ◽  
Vincenzo Russo
Keyword(s):  
Levulinic Acid ◽  
Separation Efficiency ◽  
Fixed Bed ◽  
Value Added ◽  
Low Flow ◽  
Esterification Reaction ◽  
Flow Rates ◽  
Ethyl Levulinate ◽  
Wide Range ◽  
Chromatographic Reactor

Levulinic acid (LA) has been highlighted as one of the most promising platform chemicals, providing a wide range of possible derivatizations to value-added chemicals as the ethyl levulinate obtained through an acid catalyzed esterification reaction with ethanol that has found application in the bio-fuel market. Being a reversible reaction, the main drawback is the production of water that does not allow full conversion of levulinic acid. The aim of this work was to prove that the chromatographic reactor technology, in which the solid material of the packed bed acts both as stationary phase and catalyst, is surely a valid option to overcome such an issue by overcoming the thermodynamic equilibrium. The experiments were conducted in a fixed-bed chromatographic reactor, packed with Dowex 50WX-8 as ion exchange resin. Different operational conditions were varied (e.g., temperature and flow rate), pulsing levulinic acid to the ethanol stream, to investigate the main effects on the final conversion and separation efficiency of the system. The effects were described qualitatively, demonstrating that working at sufficiently low flow rates, LA was completely converted, while at moderate flow rates, only a partial conversion was achieved. The system worked properly even at room temperature (303 K), where LA was completely converted, an encouraging result as esterification reactions are normally performed at higher temperatures.

Development of an Efficient Phase Separator for Space and Ground Applications

2016 ◽  
Author(s):  
Xiongjun Wu ◽  
Greg Loraine ◽  
Chao-Tsung Hsiao ◽  
Georges L. Chahine
Keyword(s):  
Swirling Flow ◽  
Flow Behavior ◽  
Space Station ◽  
Low Flow ◽  
Design Parameters ◽  
Two Phase ◽  
Flow Rates ◽  
Void Fractions ◽  
Wide Range ◽  
Phase Separator

The limited amount of liquids and gases that can be carried to space makes it imperative to recycle and reuse these fluids for extended human operations. During recycling processes gas and liquid phases are often intermixed. In the absence of gravity, separating gases from liquids is challenging due to the absence of buoyancy. This paper discusses a phase separator that is capable of efficiently and reliably separating gas-liquid mixtures of both high and low void fractions in a wide range of flow rates that is applicable to reduced and zero gravity environments. The phase separator consists of two concentric cylindrical chambers. The fluid introduced in the space between the two cylinders enters the inner cylinder through tangential slots and generates a high intensity swirling flow. The geometric configuration is selected to make the vortex swirl intense enough to lead to early cavitation which forms a cylindrical vaporous core at the axis even at low flow rates. Taking advantage of swirl and cavitation, the phase separator can force gas out of the liquid into the central core of the vortex even at low void fraction. Gas is extracted from one end of the cylinder axial region and liquid is extracted from the other end. The phase separator has successfully demonstrated its capability to reduce mixture void fractions down to 10−8 and to accommodate incoming mixture gas volume fractions as high as 35% in both earth and reduced gravity flight tests. The phase separator is on track to be tested by NASA on the International Space Station (ISS). Additionally, the phase separator design exhibits excellent scalability. Phase separators of different dimensions, with inlet liquid flow rates that range from a couple of GPMs to a few tens of GPMs, have been built and tested successfully in the presence and absence of the gravity. Extensive ground experiments have been conducted to study the effects of main design parameters on the performance of the phase separator, such as the length and diameter of the inner cylinder; the size, location, and layout of injection slots and exit orifices, etc., on the swirling flow behavior, and on the gas extraction performance. In parallel, numerical simulations, utilizing a two-phase Navier-Stokes flow solver coupled with bubble dynamics, have been conducted extensively to facilitate the development of the phase separator. These simulations have enabled us to better understand the physics behind the phase separation and provided guideline for system parts optimization. This paper describes our efforts in developing the passive phase separator for both space and ground applications.

scholarly journals Treatment of oil and heavy metal contaminated water

2019 ◽  
pp. 83-88
Author(s):  
Bengt Sahlin ◽  
Sune Berg ◽  
K. Hakan Anderberg ◽  
Fredrik Tengstrom
Keyword(s):  
Environmental Management System ◽  
Spare Parts ◽  
Point Of View ◽  
Process Water ◽  
Low Flow ◽  
Modular System ◽  
Contaminated Water ◽  
Flow Rates ◽  
Wide Range ◽  
Voluntary Certification

The presence of oil contaminated water in many industrial processes causes a need for the development of techniques to purify waste process water. Purified process water can be reused, which is an advantage from an ecological as well as a financial point of view. Reuse of process water enables a reduction in water consumption, reduces the use of chemicals and results in less water that has to be disposed of. These factors will motivate companies to invest in equipment for purification of waste process water even if the flow rates are low. TTM-produkter is a Swedish company based in Kalmar aiming at developing know-how and equipment for water treatment. The company is together with the University of Kalmar developing a modular system for purification of process- and wastewater. The system will be on a low investment level, easy to operate and therefore well suited for small and mediumsized companies. The system will be tailored for a number of defined applications, easy to install and require almost no construction work on the building. A standard installation consists of a sludge and oil separator in polyethene placed on the floor, a hydrocyclone to remove particles and two filter cartridges filled with smart/selective adsorbents. Until now about 30 installations of the system have been made in Sweden and Poland. The installations cover a wide range of different industries such as car and bus washes, car demolishing plants, laundry services and ceramic, metal and graphic workshops. The best results from an ecological as well as a financial point of view has been achieved in mediumsized operations with a low flow rate of waste process water, for example a plant where 1-5 buses are washed each day or a machine for washing spare parts at a car demolishing plant. New environmental legislation and voluntary certification in accordance with ISO 1 4001 Environmental Management System not only forces but also motivates companies to invest in systems for treatment of waste process water even if the flow rates are low.

Numerical modeling of the degassing process of a gas-liquid mixture in hydrocyclone

2019 ◽  
Vol 5 (3) ◽  
pp. 213-229 ◽  
Author(s):  
Artem I. Varavva ◽  
Vladimir E. Vershinin ◽  
Dmitry V. Trapeznikov
Keyword(s):  
Numerical Modeling ◽  
Flow Measurement ◽  
Separation Efficiency ◽  
Liquid Mixture ◽  
Separation Process ◽  
Gas Content ◽  
Phase Flow ◽  
Flow Rates ◽  
Wide Range ◽  
Measurement Units

Centrifugal separators&nbsp;— hydrocyclones&nbsp;— are widely used in many areas of the national economy to separate mixtures of substances of different densities. Hydrocyclones can be used for phase separation in oil, water and gas flow measurement units. The flow from the well is initially a three-phase mixture. The hydrocyclone separates the gas and liquid phases at the inlet of the measuring unit, which are then transferred to separate gas and liquid measurement units. Maintaining the accuracy of the phase flow measurement when using hydrocyclones in the measuring units requires high quality separation over a wide range of flow rates and phase contents. One of the directions of forecasting the characteristics of the separation process is based on the numerical solution of the equations of hydrodynamics of multiphase flows. Modern software of computational hydrodynamics allows to solve problems of such class in three-dimensional statement and thus to estimate efficiency of work of the device and its metrological characteristics.<br> This paper studies the processes of separation of gas-liquid mixture in hydrocyclone at different volume gas content and phase flow rates. The authors present a mathematical model with indication of the main assumptions and formulate the boundary conditions of the problem. Calculations were carried out on the open platform OpenFOAM with the use of interFoam solver. The results of numerical modeling have determined the basic structures of currents in the hydrocyclone. The influence of the initial gas content on the separation efficiency at different flow rates is investigated. The main reasons for the decrease in separation efficiency at low gas content values are revealed. In addition, the influence of the guiding elements on the separation process is considered.

Comparative study of catalytic conversion of glycerol, a by-product of transesterification, to cyclic hydrocarbons using MCM-22, ZSM-5 and alumina

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Sandeep Kumar ◽  
Dinesh Kumar ◽  
Neeru Anand ◽  
Vinay Shah
Keyword(s):  
Rate Constant ◽  
Reaction Rate ◽  
Fixed Bed ◽  
Liquid Product ◽  
Value Added ◽  
Fixed Bed Reactor ◽  
High Yield ◽  
Esterification Reaction ◽  
Glycerol Conversion ◽  
Ms Analysis

Abstract Recently chemical consumption has increased due to the growth of human population and industrialization. Depleting fuel reserves and increase in chemicals rise has led and researcher to focus on alternative bio based chemicals. Glycerol which is produced as a major byproduct from the trans-esterification reaction of fatty acids for producing biodiesel has been used in this work for conversion to value added products. Conversion of glycerol in presence of alumina, MCM-22 (pure silica based mesoporous catalyst) and ZSM-5 (Si-Al based catalyst) is investigated at different temperature and catalyst weight in a fixed bed reactor. The conversion of glycerol was found to be maximum in presence of alumina whereas maximum liquid products were obtained with ZSM-5. GC/MS analysis confirmed the production of Furan compounds in higher fraction with both alumina as well as ZSM-5 showing the importance of acid sites for the glycerol conversion to higher hydrocarbons. The GC/MS analysis of liquid product obtained in presence of catalyst was also observed with high area% of unconverted glycerol. The order is as follow 54% (MCM-22) > 44% (ZSM-5) > 42.2% (Alumina). For the investigation of the conversion for varying catalyst weight (0–3 g with 0.5 g weight difference), reaction temperature were varied between 450 and 550 °C. Different values of n = 0, 1, 2 etc. were used for the fitting of the respective plot. A change in reaction rate and the rate constant indicated that with the change of temperature, reaction rate was increased. The rate constant value obtained between 0.09 and 0.12 h−1. In all cases 450 °C and catalyst weight of 2.5 g was obtained as optimum for higher liquid yield. TGA analysis of spent catalyst also showed that alumina give high yield (∼50% by weight) of coke as compared to ZSM-5 and MCM-22.

scholarly journals Levulinic Acid-Inducible and Tunable Gene Expression System for Methylorubrum extorquens

2021 ◽  
Vol 9 ◽  
Author(s):  
Chandran Sathesh-Prabu ◽  
Young Shin Ryu ◽  
Sung Kuk Lee
Keyword(s):  
Gene Expression ◽  
Levulinic Acid ◽  
Fluorescent Protein ◽  
Expression System ◽  
Constitutive Expression ◽  
Value Added ◽  
Total Protein Content ◽  
Reporter Protein ◽  
Gene Expression System ◽  
Wide Range

Methylorubrum extorquens AM1 is an efficient platform strain possessing biotechnological potential in formate- and methanol-based single carbon (C1) bioeconomy. Constitutive expression or costly chemical-inducible expression systems are not always desirable. Here, several glucose-, xylose-, and levulinic acid (LA)-inducible promoter systems were assessed for the induction of green fluorescent protein (GFP) as a reporter protein. Among them, the LA-inducible gene expression system (HpdR/PhpdH) showed a strong expression of GFP (51-fold) compared to the control. The system was induced even at a low concentration of LA (0.1 mM). The fluorescence intensity increased with increasing concentrations of LA up to 20 mM. The system was tunable and tightly controlled with meager basal expression. The maximum GFP yield obtained using the system was 42 mg/g biomass, representing 10% of the total protein content. The efficiency of the proposed system was nearly equivalent (90%–100%) to that of the widely used strong promoters such as PmxaF and PL/O4. The HpdR/PhpdH system worked equally efficiently in five different strains of M. extorquens. LA is a low-cost, renewable, and sustainable platform chemical that can be used to generate a wide range of products. Hence, the reported system in potent strains of M. extorquens is highly beneficial in the C1-biorefinery industry to produce value-added products and bulk chemicals.

A Study of Optimum Conditions for Electrospinning Cellulose Acetate Nanofibers in Trifluoroacetic Acid Solvent

2013 ◽  
Vol 750-752 ◽  
pp. 323-327
Author(s):  
Edison Omollo ◽  
Chu Yang Zhang ◽  
Wan Jun Liu ◽  
Ncube Sizo
Keyword(s):  
Cellulose Acetate ◽  
Flow Rate ◽  
Trifluoroacetic Acid ◽  
Low Flow ◽  
Optimum Conditions ◽  
Flow Rates ◽  
Medium Voltage ◽  
Wide Range ◽  
Viscous Solution

Cellulose acetate (CA) nanofibers were electrospun in trifluoroacetic acid (TFA) under various conditions of concentration, voltage and dope flow rate while tip to collector distance (TCD) kept constant. Results showed that concentrations lower than 8 wt. % could only be electrospun at low flow rates. Bead free fibers were easily electrospun from higher CA concentrations 13 wt. % to 15 wt. %. Concentrations greater than 15 wt. % formed a viscous solution that could not be uniformly dispersed, thus impeding electrospinning. Medium voltage 20KV was found to produce good fibers while flow rates of 0.5ml/h and above, produced non-uniform fibers with a wide range. Average fiber diameters of 104nm and 129nm were formed at 13 wt. % and 15 wt. % (0.4ml/h, 20KV) respectively.

Myocardial contractile function during postischemic low-flow reperfusion: critical thresholds of NADH and O2 delivery

2004 ◽  
Vol 286 (1) ◽  
pp. H375-H380 ◽  
Author(s):  
Jason D. Stoner ◽  
Mark G. Angelos ◽  
Thomas L. Clanton
Keyword(s):  
Contractile Function ◽  
Left Ventricular ◽  
Global Ischemia ◽  
Low Flow ◽  
Critical Threshold ◽  
Rate Pressure Product ◽  
Short Term ◽  
Flow Rates ◽  
Nadh Fluorescence ◽  
Wide Range

The degree of myocardial oxygen delivery (Do2) that is necessary to reestablish functional contractile activity after short-term global ischemia in heart is not known. To determine the relationship between Do2 and recovery of contractile and metabolic functions, we used tissue NADH fluorometric changes to characterize adequacy of reperfusion flow. Isolated perfused rat hearts were subjected to global ischemia and were reperfused at variable flow rates that ranged from 1 to 100% of baseline flow. Myocardial function and tissue NADH changes were continuously measured. NADH fluorescence rapidly increased and plateaued during ischemia. A strong inverse logarithmic correlation between NADH fluorescence and reperfusion Do2 was demonstrated ( r = –0.952). Left ventricular function (rate-pressure product) was inversely related to NADH fluorescence at reperfusion flows from 25 to 100% of baseline ( r = –0.922) but not at lower reperfusion flow levels. An apparent reperfusion threshold of 25% of baseline Do2 was necessary to resume contractile function. At very low reperfusion flows (1% of baseline), another threshold flow was identified at which NADH levels increased beyond that observed during global ischemia (3.4 ± 3.0%, means ± SE, n = 9), which suggests further reduction of the cellular redox state. This NADH increase at 1% of baseline reperfusion flow was blocked by removing glucose from the perfusate. NADH fluorescence is a sensitive indicator of myocardial cellular oxygen utilization over a wide range of reperfusion Do2 values. Although oxygen is utilized at very low flow rates, as indicated by changes in NADH, a critical threshold of ∼25% of baseline Ḋo2 is necessary to restore contractile function after short-term global ischemia.

scholarly journals Catalytic Synthesis of Levulinate Esters over Zirconia and its Modified Forms Coated on Honeycomb Monoliths: Green Synthesis

2019 ◽  
Vol 31 (9) ◽  
pp. 1993-1999
Author(s):  
Reena Saritha Serrao ◽  
S.Z. Mohamed Shamshuddin ◽  
Joyce D'souza
Keyword(s):  
Levulinic Acid ◽  
Surface Characteristics ◽  
Cost Effective ◽  
Molar Ratio ◽  
Esterification Reaction ◽  
Catalytic Materials ◽  
Ethyl Levulinate ◽  
Catalytic Material ◽  
Reaction Performance ◽  
Modified Forms

A series of solid acid catalysts such as ZrO2, Mo(VI)/ZrO2 and W(VI)/ZrO2 have been coated on honeycomb monoliths as well as synthesized in the powder forms and used as catalytic materials for synthesis of ethyl levulinate from levulinic acid and ethanol. These solid acids were characterized by BET, NH3-TPD/n-butyl amine back titration, FTIR, PXRD and SEM techniques. Effects of various reaction parameters towards the reaction performance were studied. The performance of the catalyst was tested based on nature of the catalyst (honeycomb coated or powder form), reaction time (1 to 5 h), molar ratio (1:1 to 1:12 levulinic acid to ethanol) and reusability of the catalytic material. An excellent yield (86-88 %) of ethyl levulinate was obtained under optimized conditions. An attempt is made to correlate the activity of the catalysts in this esterification reaction with their surface characteristics. The honeycomb monoliths coated with zirconia and its modified forms were found to be ecofriendly, cost-effective and reusable catalytic materials compared to their powder forms.

scholarly journals Simulation of Flow in Turbopump Vaneless and Vaned Diffusers with Fluid Injection

2000 ◽  
Vol 6 (1) ◽  
pp. 57-65
Author(s):  
Ali Ogut ◽  
Diego Garcia Pastor
Keyword(s):  
Flow Separation ◽  
Flow Region ◽  
Design Flow ◽  
Low Flow ◽  
Fluid Injection ◽  
Bottom Surface ◽  
Suction Surface ◽  
Vaned Diffuser ◽  
Flow Rates ◽  
Wide Range

In future space missions by NASA there will be a need for “Space Transfer Vehicles” to perform varying orbital transfers and descents. This requires engines capable of producing different levels of thrust. To accomplish this, the turbopumps employed in these engines should efficiently provide a wide range of flow outputs. However, current fuel and oxidizer turbopumps with vaned diffusers do not perform efficiently at off-design (low) flow rates mainly due to flow separation in the vaned diffuser.This paper evaluates the effectiveness of boundary layer control by fluid injection (blowing) for suppressing or eliminating the flow separation in a vaned diffuser. A 3-D flow model including vaneless and vaned diffusers of a liquid hydrogen (LH2) turbopump is studied using the CFD code FIDAP. The paper presents the results of the model at design and offdesign flow conditions.The model results showed that flow separation occurs at the top or suction surface of the vaneless diffuser and at the bottom or pressure surface of the vaned diffuser at off-design flow rates. When fluid injection was applied through the bottom surface of the vaned diffuser, the separated flow region was reduced almost entirely, resulting in an increase in pressure recovery of up to 21% with varying fluid injection rates. Results also showed that there is an optimum injection rate which is most effective in reducing or eliminating the region of flow separation.

Liquid Phase Esterification of Levulinic Acid into Ethyl Levulinate Over Sulphobenzylated Nanoporous Al-SBA-15 Catalyst

2019 ◽  
Vol 19 (11) ◽  
pp. 6965-6977 ◽  
Author(s):  
Sakthivel Kumaravel ◽  
Sivakumar Thiripuranthagan ◽  
Ramakrishnan Radhakrishnan ◽  
Elangovan Erusappan ◽  
Mani Durai ◽  
...  
Keyword(s):  
Levulinic Acid ◽  
Supported Catalysts ◽  
Value Added ◽  
Analytical Techniques ◽  
Primary Alcohols ◽  
Reaction Conditions ◽  
Ethyl Levulinate ◽  
Conversion Level ◽  
Ft Ir ◽  
Alkyl Levulinate

Value added chemicals, fuels, and fuel additives can be obtained from cheap bio masses such as levulinic acid. Levulinic acid is the dehydration and hydrolysis products of pentoses and hexoses. The present work deals with the synthesis of sulphobenzylated Al-SBA-15, [SO3H-Bz-Al-SBA-15], characterization by various analytical techniques such as XRD, BET, FT-IR, TGA, DTA, FE-SEM/EDS and HR-TEM/EDX techniques and evaluation of catalytic activity towards esterifi-cation of levulinic acid to ethyl levulinate under mild and non corrosive conditions. Sulphonation of the aromatic ring of the benzyl group has been done in different amounts to get nanoporous x% SO3H-Bz-Al-SBA-15 catalysts where (x ═ 0.02, 0.04, 0.06, 0.08 and 0.10% w/w). Among them 0.08% SO3H-Bz-Al-SBA-15 catalyst showed the highest conversion of levulinic acid (100%) with the highest selectivity towards ethyl levulinate (100%). Esterification of levulinic acid has been carried out with different primary alcohols and all of them yielded 100% selectivity towards alkyl levulinate. However conversion level of levulinic acid was found to be different with different alcohols. Reaction conditions have been optimized. The results were compared with other supported catalysts and discussed.

Sign in / Sign up

Export Citation Format

Share Document