scholarly journals Carbon Supported Alkaline Catalysts for Guerbet Coupling of Bioethanol

2017 ◽  
Author(s):  
György Onyestyák
Keyword(s):  
Activated Carbon ◽  
Chain Length ◽  
Reaction Temperature ◽  
Total Pressure ◽  
Aldol Reaction ◽  
Metal Free ◽  
Catalytic Activities ◽  
Heterogeneous Catalytic ◽  
Flow Through ◽  
Fuel Industry

Bioethanol valorization to butanol by continuous heterogeneous catalytic self-alkylation provides an option for the fuel industry. Dimerization of ethanol (E) was studied over activated carbon supported metal loaded and metal-free alkaline catalysts using a flow-through tube microreactor, applying WHSVE of 0.20-2.0 gE/h gcat. , 21 bar total pressure and 275-400°C reaction temperature. Activated carbon (AC) was impregnated with various alkaline salts as the catalysts of the aldol reaction. Different basicity of the investigated catalysts resulted in differing catalytic activities. Butanol was the product of highest yield. Longer chain primary aliphatic alcohols, having even number of carbon atoms were also obtained with yield decreasing significantly with increasing chain length.

THE FLOW OF FLUIDS THROUGH ACTIVATED CARBON RODS.

1952 ◽  
Vol 30 (4) ◽  
pp. 348-371 ◽  
Author(s):  
E. A. Flood ◽  
R. H. Tomlinson ◽  
A. E. Leger
Keyword(s):  
Activated Carbon ◽  
Relative Pressure ◽  
End Effects ◽  
Flow Rates ◽  
Frequency Distributions ◽  
Literal Sense ◽  
Fine Grained ◽  
Porous Bodies ◽  
Carbon Rods ◽  
Flow Through

The flow rates of the vapors of benzene, ethyl chloride, diethyl ether, methanol, and water through activated carbon rods have been found to exceed, considerably, flow rates calculated by classical equations. The excess flow rates show maxima in widely different relative pressure regions and are ascribed to flow of adsorbed material. An empirical equation is presented which correlates the observed flow rates with relevant adsorption isotherms. Classical equations of flow through elliptical and rectangular pipes are discussed with reference to flow through fine-grained porous materials. It is shown that equations of the Adzumi type are roughly valid as applied to fine-grained porous bodies, but that without a knowledge of the frequency distributions of pore sizes and shapes, flow data cannot be related to pore dimensions in any literal sense. End effects are discussed.

Potassium hydroxide as a novel catalyst for metal-free carbon nanotubes growth on powder activated carbon

2021 ◽  
pp. 413294
Author(s):  
Belal Abu Tarboush ◽  
Farouq S. Mjalli ◽  
Mohammed Abdulhakim Alsaadi ◽  
Mustafa Mohammed Aljumaily
Keyword(s):  
Carbon Nanotubes ◽  
Activated Carbon ◽  
Potassium Hydroxide ◽  
Free Carbon ◽  
Metal Free ◽  
Powder Activated Carbon ◽  
Novel Catalyst

scholarly journals Oxytetracycline Adsorption from Aqueous Solutions on Commercial and High-Temperature Modified Activated Carbons

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3481
Author(s):  
Joanna Lach ◽  
Agnieszka Ociepa-Kubicka ◽  
Maciej Mrowiec
Keyword(s):  
Activated Carbon ◽  
Aqueous Solutions ◽  
Activated Carbons ◽  
Electricity Consumption ◽  
Solution Ph ◽  
Carbon Modification ◽  
Modification Method ◽  
Flow Through ◽  
Proposed Modification ◽  
Modified Activated Carbons

The aim of the work was to evaluate the possibility of using commercial and modified activated carbons for the removal of oxytetracycline from aqueous solutions. The kinetics and statics of adsorption as well as the effect of the activated carbon dose and solution pH on the efficiency of the oxytetracycline adsorption were analyzed. Based on the study of oxytetracycline adsorption isotherms, the activated carbons were ranked in the following order: F-300 > WG-12 > Picabiol > ROW08 > WACC 8 × 30 > F-100 > WAZ 0.6–2.4. The most effective activated carbons were characterized by large specific surfaces. The best matching results were obtained for: Redlich–Peterson, Thot and Jovanovic models, and lower for the most frequently used Freundlich and Langmuir models. The adsorption proceeded better from solutions with pH = 6 than with pH = 3 and 10. Two ways of modifying activated carbon were also assessed. A proprietary method of activated carbon modification was proposed. It uses the heating of activated carbon as a result of current flow through its bed. Both carbons modified at 400 °C in the rotary kiln and on the proprietary SEOW (Joule-heat) modification stand enabled to obtain adsorbents with higher and comparable monolayer capacities. The advantage of the proposed modification method is low electricity consumption.

Sulfidation Experiments in a Pressurized Thermogravimetric Analyzer With Chinese Calcined Limestones

2005 ◽  
Author(s):  
Zhanlong Song ◽  
Mingyao Zhang
Keyword(s):  
Partial Pressure ◽  
Reaction Temperature ◽  
Total Pressure ◽  
Volume Fraction ◽  
Nitrogen Adsorption ◽  
Reaction Rates ◽  
Thermogravimetric Analyzer ◽  
Morphological Studies ◽  
Shrinking Core ◽  
Structure Properties

The sulfidation experiments with two kinds of Chinese calcined limestones were performed in a pressurized thermogravimetric analyzer (PTGA). The effects of reaction temperature (700–950°C), total pressure (0–1MPa), particle size (0.055–2mm), and H2S concentration (0.1–4%) on the sorbent conversions were analyzed. Morphological studies with scanning electron microscope and energy dispersive spectroscopy (SEM-EDS) equipment were made to obtain the pictures of solid surface and of the cross-sectioned samples. Nitrogen adsorption measurements were applied to determine the pore structure properties of the particles. Experimental results show that the sulfidation rate increases with total pressure when the volume fraction of H2S is constant. However, the rate of sulfidation decreases with the increase of total pressure when the H2S partial pressure is constant. Reaction temperature affects the sulfidation greatly, and the reaction rate increases with temperature. The sulfidation is the first order with respect to H2S partial pressure. Moreover, larger particles result in lower conversions and reaction rates. The unreacted shrinking core model was applied to describe the sulfidation to determine the kinetic parameters.

Effect of Divergence Angle on Flow Through Inlet Section of Diffuser of a Gas Turbine Combustion Chamber: The CFD Approach

2006 ◽  
Author(s):  
Digvijay B. Kulshreshtha ◽  
S. A. Channiwala ◽  
Jitendra Chaudhary ◽  
Zoeb Lakdawala ◽  
Hitesh Solanki ◽  
...  
Keyword(s):  
Combustion Chamber ◽  
Gas Turbine ◽  
Total Pressure ◽  
Divergence Angle ◽  
Velocity Head ◽  
Turbine Engine ◽  
Inlet Velocity ◽  
Pressure Losses ◽  
Flow Through ◽  
Mach Numbers

In the combustor inlet diffuser section of gas turbine engine, high-velocity air from compressor flows into the diffuser, where a considerable portion of the inlet velocity head PT3 − PS3 is converted to static pressure (PS) before the airflow enters the combustor. Modern high through-flow turbine engine compressors are highly loaded and usually have high inlet Mach numbers. With high compressor exit Mach numbers, the velocity head at the compressor exit station may be as high as 10% of the total pressure. The function of the diffuser is to recover a large proportion of this energy. Otherwise, the resulting higher total pressure loss would result in a significantly higher level of engine specific fuel consumption. The diffuser performance must also be sensitive to inlet velocity profiles and geometrical variations of the combustor relative to the location of the pre-diffuser exit flow path. Low diffuser pressure losses with high Mach numbers are more rapidly achieved with increasing length. However, diffuser length must be short to minimize engine length and weight. A good diffuser design should have a well considered balance between the confliction requirements for low pressure losses and short engine lengths. The present paper describes the effect of divergence angle on diffuser performance for gas turbine combustion chamber using Computational Fluid Dynamic Approach. The flow through the diffuser is numerically solved for divergence angles ranging from 5 to 25°. The flow separation and formation of wake regions are studied.

scholarly journals Pyrolysis of Microalgae Chlorella sp. using Activated Carbon as Catalyst for Biofuel Production

2021 ◽  
Vol 16 (1) ◽  
pp. 205-213
Author(s):  
Viqhi Aswie ◽  
Lailatul Qadariyah ◽  
Mahfud Mahfud
Keyword(s):  
Activated Carbon ◽  
Physical Properties ◽  
Reaction Temperature ◽  
Bubble Column ◽  
Packed Bed ◽  
Packed Bed Reactor ◽  
Carbon Catalyst ◽  
Chlorella Sp ◽  
Conventional Pyrolysis ◽  
Fraction Yield

Microalgae, as a potential raw material for biofuel, has several advantages compared to other biomass. One effective way to convert microalgae into biofuel is by thermal cracking or pyrolysis, and using a catalyst or not. So far, studies on the use of microalgae, that are converted into biofuels, is still use highly concentrated catalysts in packed bed reactors, which is not economical. Therefore, the aim of this study is to convert Chlorella sp. into biofuels with conventional pyrolysis without and using an activated carbon catalyst using packed bed reactor with bubble column. The reaction temperature is 400–600 °C, pyrolysis time is 1–4 hours, and the active carbon catalyst concentration is 0–2%. The 200 grams of Chlorella sp. and the catalyst was mixed in a fixed bed reactor under vacuum (−3 mm H20) condition. Next, we set the reaction temperature. When the temperature was reached, the pyrolysis was begun. After certain time was reached, the pyrolysis produced a liquid oil product. Oil products are measured for density and viscosity. The results showed that the conventional pyrolysis succeeded in converting microalgae Chlorella sp. into liquid biofuels. The highest yield of total liquid oil is obtained 50.2 % (heavy fraction yield, 43.75% and light fraction yield, 6.44%) at the highest conditions which was obtained with 1% activated carbon at a temperature and pyrolysis time of 3 hours. Physical properties of liquid biofuel are density of 0.88 kg/m3 and viscosity of 5.79 cSt. This physical properties are within the range of the national biodiesel standard SNI 7182-2012. The packed bed reactor completed with bubble column is the best choice for converting biofuel from microalgae, because it gives different fractions, so that it is easier to process further to the commercial biofuel stage. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0). 

scholarly journals Hydrocracking of Coconut Oil over Ni-Fe/HZSM-5 Catalyst to Produce Hydrocarbon Biofuel

2019 ◽  
Vol 19 (2) ◽  
pp. 319 ◽  
Author(s):  
Muhammad Al-Muttaqii ◽  
Firman Kurniawansyah ◽  
Danawati Hari Prajitno ◽  
Achmad Roesyadi
Keyword(s):  
Surface Area ◽  
Chain Length ◽  
Crystalline Structure ◽  
Reaction Temperature ◽  
Batch Reactor ◽  
Coconut Oil ◽  
Incipient Wetness Impregnation ◽  
Incipient Wetness

This present study was aimed to investigate the hydrocracking of coconut oil using Ni-Fe/HZSM-5 catalyst in a batch reactor at three reaction temperatures (350, 375, and 400 °C). The Ni-Fe/HZSM-5 catalyst was prepared by using incipient wetness impregnation. The Ni-Fe/HZSM-5 catalyst was characterized using XRD, BET, and SEM-EDX. From XRD results, the loading of Ni and Fe did not change the crystalline structure of HZSM-5 catalyst. The surface area of HZSM-5 was 425 m2/g and decreased after the addition of metals (Ni and Fe) into HZSM-5 support. These changes implied that Ni and Fe particles were successfully dispersed on the HZSM-5 surface and incorporated into HZSM-5 pore. The product of hydrocarbon biofuel was analyzed using GC-MS. The GC-MS results of hydrocarbon biofuel showed the highest compounds for n-paraffin and yield for gasoil was 39.24 and 18.4% at a temperature of 400 °C, respectively. The reaction temperature affected the yield and the composition of hydrocarbon biofuel. At this reaction temperature condition, decarboxylation and decarbonylation were favored; lead to the formation of n-alkanes with an odd number of carbon atoms chain length.

Influence of Backward- and Forward-Facing Steps on the Flow Through a Turning Mid Turbine Frame

2017 ◽  
Vol 139 (12) ◽  
Author(s):  
Sabine Bauinger ◽  
Emil Goettlich ◽  
Franz Heitmeir ◽  
Franz Malzacher
Keyword(s):  
High Pressure ◽  
Total Pressure ◽  
Test Rig ◽  
Test Setup ◽  
Aero Engine ◽  
Total Temperature ◽  
Flow Through ◽  
Run Up ◽  
Compact Design ◽  
Probe Measurements

For this work, reality effects, more precisely backward-facing steps (BFSs) and forward-facing steps (FFSs), and their influence on the flow through a two-stage two-spool turbine rig under engine-relevant conditions were experimentally investigated. The test rig consists of an high pressure (HP) and an low pressure (LP) stage, with the two rotors rotating in opposite direction with two different rotational speeds. An S-shaped transition duct, which is equipped with turning struts (so-called turning mid turbine frame (TMTF)) and making therefore a LP stator redundant, connects both stages and leads the flow from a smaller to a larger diameter. This test setup allows the investigation of a TMTF deformation, which occurs in a real aero-engine due to non-uniform warming of the duct during operation—especially during run up—and causes BFSs and FFSs in the flow path. This happens for nonsegmented ducts, which are predominantly part of smaller engines. In the case of the test rig, steps were not generated by varying temperature but by shifting the TMTF in horizontal direction while the rotor and its casing were kept in the same position. In this way, both BFSs and FFSs between duct endwalls and rotor casing could be created. In order to avoid steps further downstream of the interface between HP rotor and TMTF, the complete aft rig was moved laterally too. In this case, the aft rig incorporates among others the LP rotor, the LP rotor casing, and the deswirler downstream of the LP stage. In order to catch the influence of the steps on the whole flow field, 360 deg rake traverses were performed downstream of the HP rotor, downstream of the duct, and downstream of the LP rotor with newly designed, laser-sintered combi-rakes for the measurement of total pressure and total temperature. Only the compact design of the rakes, which can be easily realized by additive manufacturing, makes the aforementioned 360 deg traverses in this test rig possible and allows a number of radial measurements positions, which is comparable to those of a five-hole probe. To get a more detailed information about the flow, also five-hole probe measurements were carried out in three measurement planes and compared to the results of the combi-rakes.

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