Global Reaction Model to Describe the Kinetics of Catalytic Pyrolysis of Coffee Grounds Waste

2017 ◽  
Vol 899 ◽  
pp. 173-178 ◽  
Author(s):  
Ronydes Batista Jr. ◽  
Bruna Sene Alves Araújo ◽  
Pedro Ivo Brandão e Melo Franco ◽  
Beatriz Cristina Silvério ◽  
Sandra Cristina Danta ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Large Scale ◽  
Catalytic Pyrolysis ◽  
Petroleum Products ◽  
Reaction Model ◽  
Heating Rates ◽  
Coffee Grounds ◽  
One Step ◽  
Global Reaction ◽  
The One

In view of the constant search for new sources of renewable energy, the particulate agro-industrial waste reuse emerges as an advantageous alternative. However, despite the advantages of using the biomass as an energy source, there is still strong resistance as the large-scale replacement of petroleum products due to the lack of scientifically proven efficient conversion technologies. In this context, the pyrolysis is presented as one of the most widely used thermal decomposition processes. The knowledge of aspects of chemical kinetics, thermodynamics these will, heat and mass transfer, are so important, since influence the quality of the product. This paper presents a kinetic study of slow pyrolysis of coffee grounds waste from dynamic thermogravimetric experiments (TG), using different powder catalysts. The primary thermal decomposition was described by the one-step reaction model, which considers a single global reaction. The kinetic parameters were estimated using nonlinear regression and the differential evolution method. The coffee ground waste was dried at 105°C for 24 hours. The sample in nature was analyzed at different heating rates, being 10, 15, 20, 30 and 50 K/min. In the catalytic pyrolysis, about 5% (w/w) of catalyst were added to the sample, at a heating rate of 30 K/min. The results show that the one-step model does not accurately represent the data of weight loss (TG) and its derivative (DTG), but can do an estimative of the activation energy reaction, and can show the differences caused by the catalysts. Although no one can say anything about the products formed with the addition of the catalyst, it would be necessary to micro-pyrolysis analysis, we can say the influence of the catalyst in the samples, based on the data obtained in thermogravimetric tests.

An approach combining additive manufacturing and dielectrophoresis for 3D-structured flexible lead-free piezoelectric composites for electromechanical energy conversion

2021 ◽  
Author(s):  
Zehuan Wang ◽  
Jin Cheng ◽  
Renchao Hu ◽  
Xiaoting Yuan ◽  
Zhonghui Yu ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Large Scale ◽  
Lead Free ◽  
Piezoelectric Composites ◽  
Additive Manufacturing Technology ◽  
Electromechanical Energy Conversion ◽  
Electromechanical Energy ◽  
One Step ◽  
The One ◽  
Piezoelectric Devices

Additive manufacturing technology has promoted the development of piezoelectric devices, from the one-step moulding of micro-miniature devices to large-scale devices.

Zeolite Supported Bimetallic Catalyst System: The Effect of Metal Loading for Catalytic Pyrolysis of Jatropha Residue

2017 ◽  
Vol 751 ◽  
pp. 494-499
Author(s):  
Vituruch Goodwin ◽  
Phanwatsa Amnaphiang ◽  
Pimpreeya Thungngern ◽  
Kong Kah Shin ◽  
Parncheewa Udomsap ◽  
...  
Keyword(s):  
Bimetallic Catalysts ◽  
Catalytic Pyrolysis ◽  
Bimetallic Catalyst ◽  
Supported Catalysts ◽  
Acid Sites ◽  
One Step ◽  
Step Loading ◽  
Loading Sequence ◽  
Xrd Patterns ◽  
The One

Two transition metals were loaded on H-ZSM-5 zeolite to produce bimetallic zeolite supported catalysts for catalytic pyrolysis reaction. Ni and Co metal were loaded on H-ZSM-5 via wet impregnation method. The loading sequence was applied using one-step and two-step loading method. The different loading sequence affect surface properties of catalyst and catalytic activity in pyrolysis reaction. The bimetallic catalysts were prepared at Ni+Co metal loading content of 10+10 wt% (Ni:Co=1:1) to 10+20 wt% (Ni:Co=1:2 or 2:1). All bimetallic catalysts supported on H-ZSM-5 were calcined and characterized by X-ray Diffraction (XRD), Surface area analysis (BET) and Temperature Programmed Desorption of ammonia (NH3-TPD). The XRD patterns of bimetallic zeolite supported catalysts revealed that loading of two metals at high content affect crystalline structural of ZSM-5 support. All XRD patterns illustrated peaks characteristic of ZSM-5, cobalt oxide and nickel oxide. The NH3-TPD results showed number of acid sites of the catalyst which revealed that the acid sites of ZSM-5 support was weakened with transition metal added. The two-step loading of 10+20 wt% metals on ZSM-5 reduced the peak intensities of NH3 desorption due to the metal particles aggregate on acid sites of ZSM-5. The two-step 10+20 wt% bimetallic catalysts has the lowest surface acidity, followed by the one-step 10+20 wt%, the two-step 10+10 wt% and the one-step 10+10 wt% bimetallic catalysts, respectively. Jatropha residue was used for catalytic pyrolysis study. Jatropha residue and bimetallic catalyst was pyrolyzed at 500 °C in a pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). The product vapor was analyzed by GC/MS for the different groups of organic products such as fatty acid, aldehydes, ketones, aliphatic hydrocarbons, aromatic hydrocarbons and nitrogen compounds. The product from catalytic pyrolysis of jatropha residue with bimetallic zeolite supported catalysts enhance deoxygenation reaction that resulted in high aliphatic and aromatic hydrocarbons product. The one-step loading at ratio Ni:Co = 1:1 (10+10 wt%) gave the highest hydrocarbons product yield at 57.81%.

scholarly journals Improving the Activity of Fe/C/N ORR Electrocatalyst Using Double Ammonia Promoted CO2 Laser Pyrolysis

2020 ◽  
Vol 6 (4) ◽  
pp. 63
Author(s):  
Henri Perez ◽  
Mathieu Frégnaux ◽  
Emeline Charon ◽  
Arnaud Etcheberry ◽  
Olivier Sublemontier
Keyword(s):  
Co2 Laser ◽  
Large Scale ◽  
Laser Energy ◽  
Reduction Reaction ◽  
Laser Pyrolysis ◽  
Highly Active ◽  
One Step ◽  
Orr Activity ◽  
Set Up ◽  
The One

Recently, we reported the use of CO2 laser pyrolysis for the synthesis of promising Fe/C/N electrocatalysts for Oxygen Reduction Reaction (ORR) in fuel cells. The set-up used single laser pyrolysis of an aerosolized solution of iron acetylacetonate in toluene with ammonia, both as laser energy transfer agent and nitrogen source. In the present paper, we investigate the effect of a second ammonia promoted CO2 laser pyrolysis on the feature and ORR activity of Fe/C/N electrocatalysts. Indeed, compared to single pyrolysis, the second ammonia promoted CO2 laser pyrolysis could be an interesting way to synthesize in one-step performing ORR electrocatalysts on a large scale. For this comparison, a two-stage reactor was built, allowing both single ammonia-induced CO2 laser pyrolysis as reported previously or double ammonia-induced CO2 laser pyrolysis. In the latter configuration, the catalyst nanopowder flow is formed at the first stage of the reactor, then mixed with a second ammonia flow and allowed to cross a second CO2 laser beam, thus undergoing a second ammonia-induced CO2 laser pyrolysis before being collected on filters. It is found that the second ammonia-induced CO2 laser pyrolysis significantly improves the ORR performances of the materials prepared by single CO2 laser pyrolysis. The effect is demonstrated for three different catalysts for which the onset potentials for the ORR from single-stage to double-stage configuration increase from 625 mV to 845 mV, 790 mV to 860 mV, and 800 mV to 885 mV, respectively. The selectivity of the ORR was determined at 600 mV/SHE and lie between 3.41 and 3.72. These promising performances suggesting potentialities for the one-step formation of highly active Fe/C/N ORR electrocatalysts are discussed, based on results of surface analysis by XPS, specific surface area measurements, and Raman spectroscopy.

A Simple and Effective Method for the Preparation of Porous Graphene Nanosheets

2015 ◽  
Vol 719-720 ◽  
pp. 123-126
Author(s):  
Jin Sun ◽  
Qing Zhong Xue ◽  
Yong Gang Du ◽  
Fu Jun Xia ◽  
Qi Kai Guo
Keyword(s):  
Large Scale ◽  
Graphene Nanosheets ◽  
Scale Production ◽  
Green Method ◽  
Porous Graphene ◽  
Large Scale Production ◽  
Potential Applications ◽  
One Step ◽  
Autogenous Pressure ◽  
The One

Porous graphene is a collection of graphene-related materials which exhibits properties distinct from those of graphene, and it has widespread potential applications in various fields. Several approaches have been developed to produce porous graphene. However, the large-scale production of porous graphene nanosheets still remains a great challenge. Moreover, the costs of some methods are prohibitive for its commercial production and the processes are too complicated and time-consuming. In this work, we propose a simple and green method by which graphene nanosheets can be etched by sodium hydroxide under autogenous pressure at 180 °C. The morphologies and surface elements of the porous graphene nanosheets and sizes of pores were characterized. It is demonstrated that the one-step etching of graphene nanosheets is an effective method to obtain large-scale porous graphene nanosheets with high and uniform porosity. The pores in the porous graphene nanosheets were 6 nm depth (the same as the thickness of the graphene nanosheets) and 30-50 nm width.

scholarly journals Ensemble Kalman Filtering with One-Step-Ahead Smoothing

2018 ◽  
Vol 146 (2) ◽  
pp. 561-581 ◽  
Author(s):  
Naila F. Raboudi ◽  
Boujemaa Ait-El-Fquih ◽  
Ibrahim Hoteit
Keyword(s):  
Data Assimilation ◽  
Large Scale ◽  
Sequential Data ◽  
Bayesian Filtering ◽  
Error Statistics ◽  
Background Error ◽  
One Step ◽  
The One ◽  
Lorenz 96 ◽  
Ensemble Kalman Filtering

The ensemble Kalman filter (EnKF) is widely used for sequential data assimilation. It operates as a succession of forecast and analysis steps. In realistic large-scale applications, EnKFs are implemented with small ensembles and poorly known model error statistics. This limits their representativeness of the background error covariances and, thus, their performance. This work explores the efficiency of the one-step-ahead (OSA) smoothing formulation of the Bayesian filtering problem to enhance the data assimilation performance of EnKFs. Filtering with OSA smoothing introduces an updated step with future observations, conditioning the ensemble sampling with more information. This should provide an improved background ensemble in the analysis step, which may help to mitigate the suboptimal character of EnKF-based methods. Here, the authors demonstrate the efficiency of a stochastic EnKF with OSA smoothing for state estimation. They then introduce a deterministic-like EnKF-OSA based on the singular evolutive interpolated ensemble Kalman (SEIK) filter. The authors show that the proposed SEIK-OSA outperforms both SEIK, as it efficiently exploits the data twice, and the stochastic EnKF-OSA, as it avoids observational error undersampling. They present extensive assimilation results from numerical experiments conducted with the Lorenz-96 model to demonstrate SEIK-OSA’s capabilities.

Thermal decomposition of un-irradiated and γ-ray irradiated holmium acetate tetrahydrate. Part 1: kinetics of nonisothermal dehydration of un-irradiated and γ-ray irradiated Ho(CH3COO)3⋅4H2O

2018 ◽  
Vol 106 (9) ◽  
pp. 775-785 ◽  
Author(s):  
Norhan Farghly Rashwan ◽  
Hossam Wahid ◽  
AbdelRahman AbdelMonem Dahy ◽  
Refaat Mohamed Mahfouz
Keyword(s):  
Thermal Decomposition ◽  
Absorbed Dose ◽  
Isoconversional Methods ◽  
Reaction Model ◽  
Host Lattice ◽  
Isothermal Kinetics ◽  
Conversion Degree ◽  
Acetate Tetrahydrate ◽  
Heating Rates ◽  
Γ Ray

Abstract Nonisothermal dehydration of un-irradiated and γ-ray irradiated holmium acetate tetrahydrate with 103 kGy total γ-ray dose absorbed was studied in air atmosphere. The thermal decomposition experiments were conducted at heating rates of (5, 7.5 and 10°C/min). The results showed that for un-irradiated material, the dehydration process proceeds in two decomposition steps with the elimination of 3.0 and 1.0 moles of H2O, respectively. The apparent activation energy, Ea, as given by both linear and nonlinear isoconversional methods showed dependence upon the conversion degree, α, in the range of 0.2–0.75 for the two dehydration steps. In the first dehydration step, the Ea decreases from 228.0 kJ/mol at the beginning of the decomposition to ≈64.0 kJ/mol at the end of the process. In the second dehydration step, the Ea increases from 42.0 to 72.0 kJ/mol by progressively increasing in α. Compared with solid state reaction models, the two reactions are best described by diffusion (D4) and nucleation (A3) models for the first and second dehydration steps, respectively. The results derived from nonisothermal data present a reliable prediction of isothermal kinetics. Straight lines and reduced time plots methods were applied for the determination of the kinetic triplet [Ea, ln A, and reaction model f(α)] from predicted isothermal data. For γ-ray irradiated samples of Ho(CH3COO)3⋅4H2O with 103 kGy total absorbed dose, the dehydration proceeds in two overlapped steps controlled by D3 model. X-ray data showed phase transformation from monoclinic (SG P2/m) to tetragonal phase (SG P4/mmm) by the elimination of water content from the entire structure of Ho(CH3COO)3⋅4H2O. γ-Ray irradiation effects on the thermal decomposition of Ho(CH3COO)3⋅4H2O were evaluated and discussed based on the formation of trapped electrons, point defects, cation and anion vacancies and cluster imperfections in the host lattice of Ho(CH3COO)3⋅4H2O.

Preparation and Thermal Decomposition Mechanism of Zn2+-Doped Mg,Al-Hydrotalcite Nanocrystalline

2007 ◽  
Vol 336-338 ◽  
pp. 2071-2073 ◽  
Author(s):  
Qing Li Ren ◽  
Qiang Luo
Keyword(s):  
Thermal Decomposition ◽  
Atmospheric Pressure ◽  
Thermal Decomposition Mechanism ◽  
Test Results ◽  
Reaction Method ◽  
Liquid Reaction ◽  
Thermal Mechanism ◽  
One Step ◽  
Preparation And Thermal Decomposition ◽  
The One

The highly pure nanocrystalline Mg,Al-hydrotalcite with Zn2+ doping was synthesized by the one-step liquid reaction method at atmospheric pressure. And the preparation of the Zn2+-doped Mg,Al-hydrotalcite nanocrystalline was investigated according to the results of XRD, TEM, IR and DSC. Moreover, based on the DSC test results, the thermal mechanism functions of the Mg,Al-hydrotalcite with Zn2+ doping are studied in detail after calculation and comparison.

A modified “gel-blowing” strategy toward the one-step mass production of a 3D N-doped carbon nanosheet@carbon nanotube hybrid network for supercapacitors

Nanoscale ◽  
2019 ◽  
Vol 11 (16) ◽  
pp. 7624-7633 ◽  
Author(s):  
Weiwei Zhou ◽  
Yu Du ◽  
Jinjue Zeng ◽  
Fei Liu ◽  
Yongming Zhu
Keyword(s):  
Carbon Nanotube ◽  
Mass Production ◽  
Large Scale ◽  
Hybrid Network ◽  
Carbon Nanosheets ◽  
One Step ◽  
Large Scale Synthesis ◽  
The One

We have realized the synchronous and large-scale synthesis of 1D CNTs on 2D N-doped carbon nanosheets (NCNS) by a one-step annealing of a gel precursor.

Study on Pyrolysis Characteristics of Corn Straw

2011 ◽  
Vol 9 (1) ◽  
Author(s):  
Zhengqi Li ◽  
Zhichao Chen ◽  
Chunlong Liu ◽  
Zhiyong Hu ◽  
Wei Zhao ◽  
...  
Keyword(s):  
Activation Energy ◽  
Mass Loss ◽  
Loss Ratio ◽  
Corn Straw ◽  
Heating Rates ◽  
Pyrolysis Characteristics ◽  
Ratio Curve ◽  
Step Model ◽  
One Step ◽  
The One

Pyrolysis characteristics of corn straw samples (corn stalks skins, corn stalks cores, corn bracts and corn leaves) was performed using thermogravimetric analysis Three heating rates (20, 50 and 100 k min-1) were applied with a final temperature of 900°C. The maximum pyrolysis rates increased with the heating rate increasing and the temperature at the peak pyrolysis rate also increased. The activation energy and the temperature interval of pyrolysis for these samples had only slightly increasing at different heating rates. The one-step model was used to obtain the pre-exponential and the activation energy. Through calculating, we obtain the mass loss ratio curve. The three models have similar results. The one-step model is simpler and suitable for the simulation of the mass loss ratio curve.

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