Microwave Induced Pyrolysis Research Papers (original) (raw)

Prediction of relative response factor GC/MS of bio-oil GC/FID of bio-oil HPLC/MS of bio-oil a b s t r a c t A simple procedure was suggested for the chromatographic analyses of bio-oils from pyrolysis of various feedstock employing different technologies. An acetonitrile solution of each bio-oil was prepared without any extraction or other sample pretreatments. Preliminary thin layer chromatography showed a large number of compounds having a broad range of retention factors (Rfs) among 0–1. Products having a retention factor over 0.9 were mainly detected by GC while some other compounds were only identified by HPLC. GC/MS-FID analysis was used to identify and quantify compounds using peak areas and relative response factors (RRFs). A new equation was proposed to estimate RRFs of compounds identified via their MS spectra when experimental RRFs were not readily available. The novel procedure was employed to characterize bio-oils from pyrolysis of wood of different source or obtained using different pyrolysis procedure. Using this RRF method guaiacol, furfural, butan-2-one, levoglucosan, acetic acid and many other compounds were quantified in bio-oil samples. Different amount of them were found as a function of the type of wood, and pyrolysis conditions adopted. For instance levoglucosan was the main compound using carbon as MW absorber however acetic acid was prevalent when a MW absorber was not employed and both of them were absent in bio-oils from classical heating. The HPLC/MS of bio-oils showed cyclohexan-carboxylic acid, 1,2,4-trimethoxybenzene and 2,6-dimethylphenol among the main products present in all bio-oils. On the contrary 4-hydroxyacetophenone and (3,4,5-trimethoxy) acetophenone were present in bio-oil from pyrolysis of wood using MW oven and 2,5-furandiylmethanol when a MW oven without any absorber was employed. Cyclohexanone was present in bio-oils obtained with a thermal heating or a MW oven without any absorber.

- by
- •
- GC-MS, GCMS and LCMS, Microwave Induced Pyrolysis, Analytical Chemistry HPLC

The issue of sustainability is a growing concern and has led to many environmentally friendly chemical productions through a great intensification of the use of biomass conversion processes. Thermal conversion of biomass is one of the most attractive tools currently used, and pyrolytic treatments represent the most flexible approach to biomass conversion. In this scenario, microwave-assisted pyrolysis could be a solid choice for the production of multi-chemical mixtures known as bio-oils. Bio-oils could represent a promising new source of high-value species ranging from bioactive chemicals to green solvents. In this review, we have summarized the most recent developments regarding bio-oil production through microwave-induced pyrolytic degradation of biomasses.

- by Mattia Bartoli
- •
- Pyrolysis, Biomass Pyrolysis, Microwave Induced Pyrolysis, Biooil

This paper begins with a review on the current techniques used for the treatment and recovery of waste oil, which is then followed by an extensive review of the recent achievements in the sustainable development and utilization of pyrolysis techniques in energy recovery from waste oils. The advantages and limitations shown by the use of pyrolysis technique and other current techniques were discussed along with the future research that can be performed on the pyrolysis of waste oil. It was revealed that the current techniques (transesterification, hydrotreating, gasification, solvent extraction, and membrane technology) are yet to be sustainable or completely feasible for waste oil treatment and recovery. It was established that pyrolysis techniques offer a number of advantages over other existing techniques in recovering both the energetic and chemical value of waste oil by generating potentially useful pyrolysis products suitable for future reuse. In particular, microwave pyrolysis shows a distinct advantage in providing a rapid and energy-efficient heating compared to conventional pyrolysis techniques, and thus facilitating increased production rates. It was found that microwave pyrolysis of waste oil showed good performance with respect to product yield, reaction time, energy consumption, and product quality, and thus showing exceptional promise as a sustainable means for energy recovery from waste oils. Nevertheless, it was revealed that some important characteristics of the pyrolysis process have yet to be fully investigated. It was thus concluded that more studies are needed to extend existing understanding in the optimal reaction and process parameters in order to develop the pyrolysis technology to be a sustainable and commercially viable route for energy recovery from problematic waste oils.

- by Su Shiung Lam and +3
- •
- Municipal Solid Waste Management, Waste recycling, Waste Management, Pyrolysis

Biomass pyrolysis is a promising renewable sustainable source of fuels and petrochemical substitutes. It may help in compensating the progressive consumption of fossil-fuel reserves. The present article outlines biomass pyrolysis. Various types of biomass used for pyrolysis are encompassed, e.g., wood, agricultural residues, sewage. Categories of pyrolysis are outlined, e.g., flash, fast, and slow. Emphasis is laid on current and future trends in biomass pyrolysis, e.g., microwave pyrolysis, solar pyrolysis, plasma pyrolysis, hydrogen production via biomass pyrolysis, co-pyrolysis of biomass with synthetic polymers and sewage, selective preparation of high-valued chemicals, pyrolysis of exotic biomass (coffee grounds and cotton shells), comparison between algal and terrestrial biomass pyrolysis. Specific future prospects are investigated, e.g., preparation of supercapacitor biochar materials by one-pot one-step pyrolysis of biomass with other ingredients, and fabricating metallic catalysts embedded on biochar for removal of environmental contaminants. The authors predict that combining solar pyrolysis with hydrogen production would be the eco-friendliest and most energetically feasible process in the future. Since hydrogen is an ideal clean fuel, this process may share in limiting climate changes due to CO 2 emissions.
Keywords Sustainable and renewable energy source; Fossil-fuel alternatives; Biomass pyrolysis; Biofuel (bio-oil, biogas, biochar); Charcoal (activated carbon); Hydrogen fuel

- by Prof Dr Yehia Fahmy and +2
- •
- Environmental Engineering, Environmental Science, Development Economics, Environmental Economics

This study investigates the effects of different parameters such as biomass composition, moisture content, particle size, heating rate, temperature, inert gas, reactor system, and catalyst on the production of hydrogen gas (HG) and other... more

- by Mark Gronnow and +2
- •
- Chemical Engineering, Analytical Chemistry, Microwave, Biomass

Microwave-assisted pyrolysis is a promising thermochemical technique to convert waste polymers and biomass into raw chemicals and fuels. However, this process involves several issues related to the interactions between materials and microwaves. Consequently, the control of temperature during microwave-assisted pyrolysis is a hard task both for measurement and uniformity during the overall pyrolytic run. In this review, we introduce some of the main theoretical aspects of the microwaves-materials interactions alongside the issues related to microwave pyrolytic processability of materials.

- by Mattia Bartoli
- •
- Pyrolysis, Microwave Induced Pyrolysis, Microwave Assisted Pyrolysis

This research project was focused on the use of microwavess (MW) as an alternative energy source, microwavess, for pyrolytic treatments of waste polymeric materials. Particularly it was focused on processing waste biomasses using a multimode microwavess oven in a batch process using different reaction conditions and correlating the products obtained with the biomass tested and the conditions adopted.
The liquid fraction, also known as bio-oil, has been obtained with very interesting yields (from 20 to 40 %) and showed very promising performances (i.e. low viscosity and limited water content). A large set of analysis was run to characterize the very complex nature of bio-oil: gas chromatographic analysis (GC-MS, GC-FID; spectroscopic analysis (UV-Vis, FT-IR ATR); NMR (1H-NMR); rheological and proximate analysis.
Solids, also known as biochar, have been characterized by FT-IR ATR, ultimate and proximate analysis to assess its possible uses and proving to be suitable as a solid fuel for carbon sequestration processes. Furthermore the samples did not contain any extractable materials.
-cellulose was studied in order to evaluate the behaviour of the main component of lignocellulosic biomasses during microwavess assisted pyrolysis (MAP). With the same aim MAP of Kraft lignin at different pressure was tested to correlate the residual pressure on the yield of aromatics compounds generated from the most abundant aromatic containing polymer.
Finally MAP of common wastes coming from different lignocellulosic sources such as Arundo donax, Oliva europea, Vitis vinifera, and different poplar clones, were tested under different pyrolysis conditions in order to evidence their behaviour during MAP experiments.
Various degradation mechanisms of cellulose and Kraft lignin were deeply investigated and some reaction pathways proposed. The interaction between microwaves absorbers and feedstocks was also object of this study.

Microwave vacuum pyrolysis of palm kernel shell was examined to produce engineered biochar for application as additive in agriculture application. The pyrolysis approach, performed at 750 W of microwave power, produced higher yield of porous biochar (28 wt%) with high surface area (270 cm 2 /g) compared to the yield obtained by conventional approach (< 23 wt%). Addition of the porous biochar in mushroom substrate showed increased moisture content (99%) compared to the substrate without biochar (96%). The mushroom substrate added with biochar (150 g) was optimal in shortening formation, growth, and full colonization of the mycelium

- by Rock Keey Liew
- •
- BIOCHAR, Mushroom cultivation, Microwave Induced Pyrolysis

Several organs (rhizomes, stems and leaves) of Arundo donax, a perennial cane ubiquitary in the mediter-ranean area, were pyrolyzed using a microwave assisted pyrolysis with carbon as microwave absorber and different reaction conditions. Relevance of the organs on the yields and products was shown and, as a function of the conditions adopted, these results may be emphasized or reduced. In all experiments a small gas (4.6%) and a large biochar production (up to 62.9%) were obtained while bio-oil was formed in amount up to 40.9% as a one-phase dark brown liquid having low viscosity. These liquids were characterized through several techniques among which FT-IR, 1 H NMR, and a quantitative GC–MS analysis. These bio-oils contained a huge amount of aromatics, acetic acid, furanes and, sometimes, levoglucosan (up to 47.6 g/L). The microwave assisted pyrolysis of waste from several organs of Arundo donax appears as an interesting way to dispose these materials and to obtain useful biochemicals and fuels through a fast pyrolysis process.

- by Mattia Bartoli
- •
- Biomass Pyrolysis, Microwave pyrolysis, Microwave Induced Pyrolysis

Wood pellets were pyrolyzed using a microwave oven and different microwave power, apparatus set-up
and microwave absorbers (none, Fe, and carbon).
Pyrolysis was realized in a short time in the presence of Fe or carbon while it was incomplete if the
absorber was not present. Furthermore when the absorber was present the shape of the pellets remained
unaltered while if the absorber was not employed pellets were disaggregated.
Three fractions were collected from each pyrolysis: a gas, a liquid also called bio-oil and a solid called
bio-char. The bio-oil contained two phases and they were quantitatively characterized through a GC/MSFID
procedure using an internal standard according to a previously reported method. HPLC/MS, FTIR and
1H NMR spectroscopy were also employed for characterization of these liquids. Cellulose pyrolysis
products were present in the upper phase such as water, acetic acid, furans (such as furfural),
carbohydrates and their derivatives. Compounds from pyrolysis of lignin such as phenols and veratric
acid were present in the bottom phase.
The microwave assisted pyrolysis showed the possibility to efficiently convert wood pellets in different
products. The main economical important components may be separated and used as chemicals, natural
drugs or pesticides, while the remaining components, the solid and the gas may be used for energy production
(solid and bio-oil). Solid may be also used for carbon sequestration.

- by Mattia Bartoli
- •
- Biomass Pyrolysis, Microwave pyrolysis, Microwave Induced Pyrolysis

Microwave pyrolysis was performed on waste engine oil pre-mixed with different amounts of metallic-char catalyst produced previously from a similar microwave pyrolysis process. The metallic-char catalyst was first prepared by pretreatment with calcination followed by analyses to determine its various properties. The heating characteristics of the mixture of waste oil and metallic-char during the pyrolysis were investigated, and the catalytic influence of the metallic-char on the yield and characteristics of the pyrolysis products are discussed with emphasis on the composition of oil and gaseous products. The metallic-char, detected to have a porous structure and high surface area (124 m2/g), showed high thermal stability in a N2 atmosphere and it was also found to have phases of metals and metal oxides attached or adsorbed onto the char, representing a potentially suitable catalyst to be used in pyrolysis cracking process. The metallic-char initially acted as an adsorptive-support to adsorb metals, metal oxides and waste oil. Then, the char became a microwave absorbent that absorbed microwave energy and heated up to a high temperature in a short time and it was found to generate arcing and sparks during microwave pyrolysis of the waste oil, resulting in the formation of hot spots (high temperature sites with temperature up to 650 °C) within the reactor under the influence of microwave heating. The presence of this high temperature metallic-char, the amounts of which are likely to increase when increasing amounts of metallic-char were added to the waste oil (5, 10, and 20 wt% of the amount of waste oil added to the reactor), had provided a reducing chemical environment in which the metallic-char acted as an intermediate reductant to reduce the adsorbed metals or metal oxides into metallic states, which then functioned as a catalyst to provide more reaction sites that enhanced the cracking and heterogeneous reactions that occurred during the pyrolysis to convert the waste oil to produce higher yields of light hydrocarbons, H2 and CO gases in the pyrolysis products, recording a yield of up to 74 wt% of light C5-C10 hydrocarbons and 42 vol% of H2 and CO gases. The catalytic microwave pyrolysis produced 65-85 wt% yield of pyrolysis-oil containing C5-C20 hydrocarbons that can potentially be upgraded to produce transport-grade fuels. In addition, the recovered pyrolysis-gases (up to 33 wt%) were dominated by aliphatic hydrocarbons (up to 78 vol% of C1-C6 hydrocarbons) and significant amounts of valuable syngas (up to 42 vol% of H2 and CO in total) with low heating values (LHV) ranging from 4.7 to 5.5 MJ/m3, indicating that the pyrolysis-gases could also be used as a gaseous fuel or upgraded to produce more hydrogen as a second-generation fuel. The results indicate that the metallic-char shows advantages for use as a catalyst in microwave pyrolysis treatment of problematic waste oils.

- by Su Shiung Lam and +1
- •
- Catalysts, Municipal Solid Waste Management, Waste recycling, Waste Management

Microwave Assisted Pyrolysis (MAP) of the plastic fraction of Waste from Electric and Electronic Equipment (WEEE) from end-life computers was run with different absorbers and setups in a multimode batch reactor. A large amount of various different liquid fractions (up to 76.6 wt%) were formed together with a remarkable reduction of the solid residue (up to 14.2 wt%). The liquid fractions were characterized using the following different techniques: FT-IR ATR, 1 H NMR and a quantitative GC–MS analysis. The liquid fractions showed low density and viscosity, together with a high concentration of useful chemicals such as styrene (up to 117.7 mg/mL), xylenes (up to 25.6 mg/mL for p-xylene) whereas halogenated compounds were absent or present in a very low amounts.

- by Mattia Bartoli and +1
- •
- Microwave pyrolysis, Microwave Induced Pyrolysis

Cellulose was pyrolyzed using a multimode microwave oven, different microwave absorbers and experimental set ups. The microwave absorber showed a strong influence: carbon gave a large gasification of cellulose (yield of gas up to 53.8%) while Al 2 O 3 gave a high yield of bio-char (64.1%) and a low gas production (3.0%). Bio-oil was obtained with the highest yield (37.6%) using iron as microwave absorber and a condenser between the oven and the collecting system. Dark brown bio-oils having low density and viscosity due to the presence of large amount of furanosidic compounds were collected. Bio-oils were characterized through GC–MS, FT-IR, NMR, The GC–MS analysis was employed to evaluate the composition of bio-oils using calculated retention factors. A high concentration of levoglucosan (133.9 mg/mL) together with acetic acid, acetic anhydride, 1-hydroxy-2-propanone, formic acid and fur-fural were obtained using graphite as microwave absorber. A mechanisms was proposed to rationalize the formation of aromatic compounds present in bio-oils. Water contents in bio-oils were affected by all parameters of the process, mainly by the microwave absorber. The use of silica has proved to be a promising way to obtain bio-oil with low water content (13%), while pyrolysis in the presence of carbon gave a large amount of water (46%).

District heating networks are commonly addressed in the literature as one of the most effective solutions for decreasing the greenhouse gas emissions from the building sector. These systems require high investments which are returned through the heat sales. Due to the changed climate conditions and building renovation policies, heat demand in the future could decrease, prolonging the investment return period. The main scope of this paper is to assess the feasibility of using the heat demand – outdoor temperature function for heat demand forecast. The district of Alvalade, located in Lisbon (Portugal), was used as a case study. The district is consisted of 665 buildings that vary in both construction period and typology. Three weather scenarios (low, medium, high) and three district renovation scenarios were developed (shallow, intermediate, deep). To estimate the error, obtained heat demand values were compared with results from a dynamic heat demand model, previously developed and validated by the authors. The results showed that when only weather change is considered, the margin of error could be acceptable for some applications (the error in annual demand was lower than 20% for all weather scenarios considered). However, after introducing renovation scenarios, the error value increased up to 59.5% (depending on the weather and renovation scenarios combination considered). The value of slope coefficient increased on average within the range of 3.8% up to 8% per decade, that corresponds to the decrease in the number of heating hours of 22-139h during the heating season (depending on the combination of weather and renovation scenarios considered). On the other hand, function intercept increased for 7.8-12.7% per decade (depending on the coupled scenarios). The values suggested could be used to modify the function parameters for the scenarios considered, and improve the accuracy of heat demand estimations. Abstract The fossil fuels accomplish almost 80% of the world energy needs. The ever increasing exploitation of fossil fuels has led to environmental pollution, global climate change and health problems to living beings. Hence to meet the needs of the future energy and to mitigate the environmental pollution, it is critical to look for the alternate fuels. Global energy infrastructure in the future is believed to be accomplished by the energy generated from the low-cost renewable resources. Algae biomass has emerged as a promising biofuel source, as microalgae-based biofuels are biodegradable, renewable, and eco-friendly in comparison to fossil driven fuels. This study aims to examine the importance of microalgae as an alternative renewable energy source and evaluate the key challenges in the production of microalgae biofuel.

- by Dr. Abdul-Sattar Nizami and +1
- •
- Environmental Engineering, Chemical Engineering, Environmental Science, Energy Economics

Recent concern in reserves of fossil sources of energy and chemicals has revived the interest in lignocellulose pyrolysis. This has necessitated a somewhat different look to pyrolysis, and a more understanding of its mechanism. The result has been a great progress in pyrolysis technology.
The present study outlines in a concise form the history of pyrolysis up to the present time, and it attempts to correlate various aspects of this rather versatile subject. Pyrolysis has now become a more controllable process and could be oriented to deliver solid, liquid and gas products groups within a wider ratio range and with more or less fixed chemical composition. It is even now possihle to speak not only of gasification but also of liquefaction pyrolysis. Technology of pyrolysis is very flexible. The reactors or furnaces, at present, can be stable or mobile, mini or of high capacity, and the process can he slow or very rapid, batch or continuous, mechanized or unmechanized. Pyrolysis being thermally self sustaining is in several aspects preferable to hydrogenolysis and biological gasification for producing chemicals including those used as sources for energy. In this report, pyrolytic fuels including those prepared from synthesis gas are compared to fossil fuels.
This part serves as introduction and background of the following parts of this work.

A new and simple protocol for quantitative analysis of bio-oils using gas-chromatography/mass spectrometry is suggested. Compounds
were identified via their mass spectra, and then unavailable response factors were calculated with respect to diphenyl as the internal
standard using a modified method previously suggested for gas chromatography with flame ionization detection. This new protocol was
applied to the characterization of bio-oils obtained from the pyrolysis of woods of different sources or using different pyrolysis procedures.
This protocol allowed evaluation of the yields of products from poplar pyrolysis (among 50% and 99%), while a reduced amounts
of products were identified from the pyrolysis of cellulose (between 46% and 58%). The main product was always acetic acid, but it was
formed in very large yields from poplar while lower yields were obtained from cellulose.

- by Mattia Bartoli and +1
- •
- Analytical Chemistry, Analytical Method Development, GC-MS, Microwave Induced Pyrolysis

Microwave-steam activation (MSA), an innovative pyrolysis approach combining the use of microwave heating and steam activation, was investigated for its potential production of high grade activated carbon (AC) from waste palm shell (WPS) for methylene blue removal. MSA was performed via pyrolytic carbonization of WPS to produce biochar as the first step followed by steam activation of the biochar using microwave heating to form AC. Optimum yield and adsorption efficiency of methylene blue were obtained using response surface methodology involving several key process parameters. The resulting AC was characterized for its porous characteristics , surface morphology, proximate analysis and elemental compositions. MSA provided a high activation temperature above 500°C with short process time of 15 min and rapid heating rate (≤150°C/min). The results from optimization showed that one gram of AC produced from steam activation under 10 min of microwave heating at 550°C can remove up to 38.5 mg of methylene blue. The AC showed a high and uniform surface porosity consisting high fixed carbon (73 wt%), micropore and BET surface area of 763.1 and 570.8 m 2 /g respectively , hence suggesting the great potential of MSA as a promising approach to produce high grade ad-sorbent for dye removal.

Stump-roots and leaves from different residues of short rotation coppice (SRC) of poplar clones were transformed with microwave assisted pyrolysis to produce bio-oils. These products were obtained with high yield (up to 32.0%) and small water percentage (up to 17.5%), showed low density and viscosity and were fluid at room temperature. Bio-oils were characterized with several analytical techniques: 1 H NMR, IR-ATR, and an original and a quantitative GC–MS method. Acetic and formic acids, acetic anhydride, furanes and various phenols were identified and quantified; among bio-oils a sample with high acetic acid concentration (543.3 mg/mL) was obtained. These techniques let to make possible a detailed study on the bio-oils to define a correlation between their chemical and rheological properties with the clones employed and parameters of the process.

- by Mattia Bartoli
- •
- Biomass Pyrolysis, Microwave pyrolysis, Microwave Induced Pyrolysis

- by Michael Försth
- •
- Pyrolysis, Biomass Pyrolysis, Processes, Microwave Induced Pyrolysis
- by Nyuk Ling Ma
- •
- Chemical Engineering, Microwave Induced Pyrolysis
- by peter yek nai yuh
- •
- BIOCHAR, Multidisciplinary, Mushroom cultivation, Microwave Induced Pyrolysis

Every year approximately 50 million tonnes of lignin are obtained worldwide as by-products of the paper industry and represent a potential renewable aromatic feedstock for a sustainable future carbon economy. In spite of this the availability of lignin remains largely unused so long the most part of it (ca. 98%) is still burned. For this reason pyrolysis-based technologies, such as fast pyrolysis and gasification, are considered promising methods for converting lignin into biochemicals, biomaterials, and biofuels. In this work the pyrolysis of kraft lignin were studied at reduced pressure under Microwave Assisted Pyrolysis (MAP). Experiments were carried out at different pressure (1 bar, 0.13 bar, 0.013 bar) also using a fractionating system. A multimode MW (Microwave) batch reactor was employed as oven using carbon as MW absorber. The most relevant achievements were gained at residual pressure of 0.013 kPa obtaining a 37 wt% of bio-oil in 9 min. Compositions of bio-oils were evaluated through 1 H NMR, FT-IR ATR and a quantitative GC-MS method. Analysis showed high concentration of multisubstituted aromatic ring and light linear/cyclic compounds (C2-C5) from advanced thermal degradation of side chains of the lignin structure.

- by Mattia Bartoli
- •
- Lignin, Microwave Induced Pyrolysis