The yield prediction of synthetic fuel production from pyrolysis of plasticwaste by Levenberg-Marquardt approach in feedforward neural networks model

© 2019 by the authors. The conversion of plastic waste into fuel by pyrolysis has been recognized as a potential strategy for commercialization. The amount of plastic waste is basically different for each country which normally refers to non-recycled plastics data; consequently, the production target will also be different. This study attempted to build a model to predict fuel production from different non-recycled plastics data. The predictive model was developed via Levenberg-Marquardt approach in feed-forward neural networks model. The optimal number of hidden neurons was selected based on the lowest total of the mean square error. The proposed model was evaluated using the statistical analysis and graphical presentation for its accuracy and reliability. The results showed that the model was capable to predict product yields from pyrolysis of non-recycled plastics with high accuracy and the output values were strongly correlated with the values in literature

Co-pyrolysis of Rice Husk with Underutilized Biomass Species: A Sustainable Route for Production of Precursors for Fuels and Valuable Chemicals

In this study, co-pyrolysis of rice husk with underutilized biomass, Napier grass and sago waste was carried out in a fixed bed reactor at 600 �C, 30 �C/min and 5 L/min nitrogen flowrate. Two-phase bio-oil (organic and aqueous) was collected and characterized using standard analytical techniques. 34.13–45.55 wt% total boil-oil yield was recorded using assorted biomass compared to pure risk husk biomass with 31.51 wt% yield. The organic phase consist mainly benzene derivatives with higher proportion in the oil from the co-pyrolysis process relative to the organic phase from the pyrolysis of the individual biomass while the aqueous phase in all cases was predominantly water, acids, ketones, aldehydes, sugars and traces of phenolics. This study has demonstrated a good approach towards increasing valorization of rice husk in a single reaction step for the production of high grade bio-oil, which can be transformed into fuel and valuable chemicals

Integrating anaerobic digestion and pyrolysis for treating digestates derived from sewage sludge and fat wastes

P. 32603-32614The coupling of biological and thermal technologies allows for the complete conversion of wastes into energy and biochar eliminating the problem of sludge disposal. The valorisation of fatty residues as co-substrate in a mesophilic digester of a wastewater treatment plant was studied considering an integrated approach of co-digestion and pyrolysis. Four digested samples obtained from co-digestion of sewage sludge and butcher’s fat waste were studied by thermogravimetric analysis. The activation energy corresponding to the sludge pyrolysis was calculated by a non-isothermal kinetic. Arrhenius activation energy was lower for the pyrolysis of a digested grease sample (92 kJ mol−1 obtained by OFW and 86 kJ mol−1 obtained by Vyazovkin) than for the pyrolysis of sewage sludge and its blends (164–190 kJ mol−1 obtained by OFW and 162–190 kJ mol−1 obtained by Vyazovkin). The analysis of the integrated approach of anaerobic co-digestion and pyrolysis of digestates demonstrated that the addition of 3% (w/v) of fat to the feeding sludge results in a 25% increase in the electricity obtained from biogas (if a combined heat and power unit is considered for biogas valorisation) and increasing the fat content to 15% allows for covering all thermal needs for drying of digestate and more than doubles (2.4 times) the electricity production when the scenario of digestion and pyrolysis is contemplated.S

Optimization of fuel recovery through the stepwise co-pyrolysis of palm shell and scrap tire

This study optimized the use of biomass waste to generate fuel through co-pyrolysis. In this paper, the effects of stepwise co-pyrolysis temperature and different ratios between palm shells and scrap tires in feedstock were studied to observe any improvements in the quantity and quality of the liquid yield and its byproduct. The ratio of palm shells and scrap tires varied at 100:0, 75:25, 50:50, 25:75, and 0:100. The experiment was conducted in a fixed-bed reactor. The study was divided into two scenarios. The first scenario was performed at the optimum temperature of 500 degrees C with a reaction time of 60 min. In the second scenario, the temperature was set at 500 degrees C for 60 min before the temperature was increased to 800 degrees C with a high heating rate. After the temperature reached 800 degrees C, the condition was maintained for approximately 45 min. Results showed that an increase in the liquid and gas yields was achieved when the temperature increased after optimum conditions. Increased yield was also obtained when the proportion of scrap tire was increased in the feedstock. Several other important findings are discussed in this paper, including the phases of pyrolysis oil, features of the liquid product, and characteristics of the byproducts. All products from both scenarios were analyzed by various methods to understand their fuel characteristics. (C) 2015 Elsevier Ltd. All rights reserved

Energy recovery from pyrolysis of plastic waste: Study on non-recycled plastics (NRP) data as the real measure of plastic waste

Oil produced from pyrolysis of plastics have been known for its higher calorific value than wood-based oil, in which comparable to conventional diesel. Even though many studies have been conducted on pyrolysis of plastics, the findings of those studies are not applied and reported yet according to the real portion of plastic waste. The real amount of plastic waste available is mainly derived from non-recycled plastics (NRP). NRP is defined as the plastic waste that remain in the recycling centers, which unable to be processed due to the certain restrictions. The amounts of NRP vary for each country based on daily applications. In this study, data of NRP in Malaysia, US, UK, as well as global were used to investigate the potential production of liquid fuel based on their different composition of plastic waste. Pyrolysis was conducted in a fixed bed reactor at 500 °C with nitrogen flow of 200 ml/min for 30 min reaction time. The addition of polystyrene (PS) into the NRP composition was also studied to evaluate the improvement of the liquid quality. Several important findings were discussed in this paper including some technical problems, features of the liquid product, characteristics of the by-products and potential energy recovery from NRP. The liquid product was analyzed by various methods such as FTIR, GCMS, elemental analysis and water content

Gas-phase hydrodeoxygenation of phenol over Zn/SiO2 catalysts:Effects of zinc load, temperature, weight hourly space velocity, and H 2 volumetric flow rate

The hydrodeoxygenation (HDO) of phenol catalyzed by Zn/SiO2 under atmospheric H2 pressure was investigated in a continuous fixed bed reactor. The effects of several process parameters (zinc load, reaction temperature, weight hourly space velocity (WHSV), and H2 volumetric flow rate) were evaluated to optimize process conditions. Phenol was selected as a stable model component for lignin degradation products in fast pyrolysis bio-oil. Silica-supported zinc catalysts were prepared with different loadings of the active metal (0.5%, 1%, 2%, 3%, and 4%) and assessed using characterization techniques such as XRD, ICP-OES, BET, H2-TPR/TPD, and FESEM–EDX. Reaction products including benzene, cyclohexene, and cyclohexane were identified through GC/FID analysis. Experimental results revealed that process yield increased with reaction temperature, metal loading, and WHSV. The selectivity percentages of the products were slightly changed by varying process parameters. Moreover, H2 volumetric flow rate exerted a negligible effect on product yield and selectivity

A review of the enzymatic hydroesterification process for biodiesel production

Enzymatic hydroesterification has recently attracted research interest because of the high-value products created during biodiesel production. The use of this process overcomes problems related to conventional methods for biodiesel production, such as slow reaction rate and soap formation. The method comprises two basic processes to produce fatty acid alkyl esters from triacylglycerols, namely, enzymatic hydrolysis and enzymatic esterification. Although enzymatic hydroesterification for biodiesel production has many advantages, such as lower energy consumption and converting low-quality feedstock, it has not been used on an industrial scale mainly because of some impediments, including enzyme cost and conversion efficiency. This review presents a comprehensive evaluation of recent investigations on enzymatic hydrolysis and enzymatic esterification to lower process costs and increase yields

A review of recent developments on kinetics parameters for glycerol electrochemical conversion – A by-product of biodiesel

Glycerol is a by-product produced from biodiesel, fatty acid, soap and bioethanol industries. Today, the value of glycerol is decreasing in the global market due to glycerol surplus, which primarily resulted from the speedy expansion of biodiesel producers around the world. Numerous studies have proposed ways of managing and treating glycerol, as well as converting it into value-added compounds. The electrochemical conversion method is preferred for this transformation due to its simplicity and hence, it is discussed in detail. Additionally, the factors that could affect the process mechanisms and products distribution in the electrochemical process, including electrodes materials, pH of electrolyte, applied potential, current density, temperature and additives are also thoroughly explained. Value-added compounds that can be produced from the electrochemical conversion of glycerol include glyceraldehyde, dihydroxyacetone, glycolic acid, glyceric acid, lactic acid, 1,2-propanediol, 1,3-propanediol, tartronic acid and mesoxalic acid. These compounds are found to have broad applications in cosmetics, pharmaceutical, food and polymer industries are also described. This review will be devoted to a comprehensive overview of the current scenario in the glycerol electrochemical conversion, the factors affecting the mechanism pathways, reaction rates, product selectivity and yield. Possible outcomes obtained from the process and their benefits to the industries are discussed. The utilization of solid acid catalysts as additives for future studies is also suggested

Catalyst characteristics and performance of silica-supported zinc for hydrodeoxygenation of phenol

The present investigation aimed to study the physicochemical characteristics of supported catalysts comprising various percentages of zinc dispersed over SiO2. The physiochemical properties of these catalysts were surveyed by N2physisorption (BET), thermogravimetry analysis (TGA), H2temperature-programmed reduction, field-emission scanning electron microscopy (FESEM), inductively coupled plasma-optical emission spectrometry (ICP-OES), and NH3temperature-programmed desorption (NH3-TPD). In addition, to examine the activity and performance of the catalysts for the hydrodeoxygenation (HDO) of the bio-oil oxygenated compounds, the experimental reaction runs, as well as stability and durability tests, were performed using 3% Zn/SiO2as the catalyst. Characterization of silica-supported zinc catalysts revealed an even dispersion of the active site over the support in the various dopings of the zinc. The acidity of the calcinated catalysts elevated clearly up to 0.481 mmol/g. Moreover, characteristic outcomes indicate that elevating the doping of zinc metal led to interaction and substitution of proton sites on the SiO2surface that finally resulted in an increase in the desorption temperature peak. The experiments were performed at temperature 500 °C, pressure 1 atm; weight hourly space velocity (WHSV) 0.32 (h-1); feed flow rate 0.5 (mL/min); and hydrogen flow rate 150 (mL/min). Based on the results, it was revealed that among all the prepared catalysts, that with 3% of zinc had the highest conversion efficiency up to 80%. However, the selectivity of the major products, analyzed by gas chromatography flame-ionization detection (GC-FID), was not influenced by the variation in the active site doping

Kinetic parameters for glycerol electrooxidation over nitrogen- and fluorine-doped composite carbon:Dynamic electrochemical impedance spectroscopy analysis based

This study explores the mechanistic, kinetic process and parameters of nitrogen and fluorine-doped activated carbon black composite catalyst during glycerol electrooxidation in alkaline so under some precise experimental parameters. The influence of catalyst and electrochemical impedance spectroscopy (EIS) perturbation amplitude were systematically studied. The kinetic parameters from steady-state measurement and microkinetic modelling study reveal that glycerol electrooxidation undergoes complicated mechanism. From the chronoamperometry study, the nitrogen-doped sample (ACB-N2) shows a remarkable activity and stability, but the performance was improved upon the simultaneous doping of fluorine to form ACB-N2F2. The best rate constant was obtained by ACB-N2F2 (7.335 × 10−3), which is by far greater than those of ACB-N2 (2.533 × 10−3) and ACB-F2 (2.012 × 10−3) for steady-state. The slope obtained from the Tafel plot of both the voltammetry and the non-linear electrochemical impedance spectroscopy measurement also confirms the superior performance of ACB-N2F2 compared to ACB-N2 and ACB-F2. The rate constant of ACB-N2F2 is almost 6 times of that of ACB-N2, and 4 times of the of ACB-F2 for the forward sweep. The exchange current density of ACB-N2F2 is almost 7 times of that of ACB-N2, and 3 times of the of ACB-F2 for the forward sweep. The methods in this study for evaluation of glycerol electrooxidation kinetic process and kinetic parameters could be used to investigate other electrocatalysts