Pyrolysis Of Peat Research Articles

Utilization of polymer wastes by joint pyrolysis with peat to produce high-calorific gas

Methods for the utilization of polymer wastes are surveyed. The results of experimental studies on the pyrolysis of peat–polyethylene mixtures depending on process conditions are reported. The yield of pyrolysis products and the composition and calorific value of gases were studied; in this case, the calorific value increased by 30–40%, as compared with the heat of combustion of gas generated from peat.

Biochar, a substitute for fossil fuels

The present piece of research is envisaged for the possibilities and usefulness of coco peat (coir dust) which is generally not considered for usefulness. Pyrolysis of coco peat was done at two different temperatures to obtain biochars and their properties were investigated. Proximate analysis gave the fixed carbon content which gave a good value for the required purpose. Characterization techniques like Scanning Electron Microscopy, X-Ray Diffraction and Fourier Transform Infra-Red Spectroscopy were employed. It was observed that depending on the pyrolysis temperature and conditions, new substances formed, the diffraction peaks changed and also there were major changes in functional groups. The cross-links were found to disintegrate with increasing temperature. The peaks unveiled the presence of silicon carbide in the biochar pyrolysed at 1000ºC. The change in the functional groups with increase in temperature manifested higher aromaticity which is an important attribute of fuels viz. petroleum, etc. Thus the present investigation can open up a new era for processing biochar from unutilized biowaste for its use as an alternative to fossil fuels.

High-temperature microwave pyrolysis of peat as a method to obtaining liquid and gaseous fuels

High-temperature microwave pyrolysis of peat as a method to obtaining liquid and gaseous fuels

Thermal Conversion of the Peat to Combustible Gases

Presented thermal characteristics of the peat and semi-coke derived on its basis. Presented the results of studies of the pyrolysis and catalytic conversion of peat and semi-coke at temperatures of 300-450 °C. According to the results of experiments to determine the composition and calorific value of combustible gases, obtained as the result of peat thermal conversion and semi-coke based on it. Presented the structure and analyzed the material balance and the energy distribution of derived products by the thermal conversion.

Effects of carbon dioxide on pyrolysis of peat

This study focuses on the mechanistic understanding of effects of CO2 on pyrolysis of peat. To do this, three pyrolytic products (i.e., syngas: H2 and CO, pyrolytic oil (tar), and biochar) were characterized. Thermal cracking of volatile organic carbons (VOCs) generated from pyrolysis of peat was enhanced in the presence of CO2. Besides the enhanced thermal cracking of VOCs, unknown reaction between CO2 and VOCs was also identified. Accordingly, CO2 played a role in enhancing syngas production and in reducing tar formation in pyrolysis of peat. This study also reveals that peat-biochar produced in CO2 exhibited a larger surface area than that produced in N2. The results shown in this paper would be used for various applications such as energy recovery from peat using a potent greenhouse gas (for example, CO2).

Dependence of Electrochemical Properties on Structure and Deeper Understanding of Sodium Insertion in Hard Carbons Used As Anode for Sodium-Ion Batteries

Nowadays, Lithium ion (Li-ion) batteries are present in many applications such as mobile phones, computers, power tools, hybrid electric (HEV) and electric (EV) vehicles. However abundance, cost and especially accessibility of lithium will be able to bring some issues for Li-ion development in the future [1]. This leads the scientist community to go back to sodium ion battery research, which decreased significantly after Li ion battery success in the 90’s. Sodium seems to be an interesting alternative to lithium because of its abundance and availability. However, in order to be competitive against other technologies, capacity, rate capability and cycle life should be improved [2]. Carbon for Na-ion battery applications has been extensively studied in the literature [3,4] whatever its form: hard carbon, carbon black, carbon nanospheres or nanotubes, carbon fibers and graphene. Especially for hard carbons the main problems reported in literature are a high first irreversible capacity and a poor cyclability. For example, Ding et al.[5] tested carbon made from peat (organic matter) pyrolysis and they obtained a reversible capacity of 255 mAh.g-1 after 200 cycles with a current density equal to 50 mA.g-1 and an initial coulombic efficiency reaching 60%. Recently Sun et al.[6] have synthesized hard carbon from shaddock peel pyrolysis. The pyrolysis temperature was varied from 800 to 1400°C and the best performances were obtained for the temperature 1200°C: the material exhibited a very high reversible capacity of around 400 mAh.g-1 with a good stability over 200 cycles and a first coulombic efficiency of 68%. Even though hard carbon structure and sodium ion insertion into these materials were studied, especially by Dahn’s group in 2000 [7,8,9], insertion mechanisms are still in debate in the literature. Dahn and coworkers developed a card-house model with two different mechanisms: in the galvanostatic curve, the sloppy part corresponds to sodium intercalation between graphene sheets and the low voltage plateau is related to the sodium insertion in micropores. Lately Bommier et al. [10] have proposed another point of view concerning this model based on ab initio calculations: the low voltage plateau is due to intercalation into sites around the defective carbon surface. In this presentation we proposed to develop two parts. The first part exhibits the dependence of electrochemical performances on hard carbon structure. All hard carbon samples are made from the same organic precursor, cellulose. The final pyrolysis temperature is varied from 700°C to 1600°C. The samples are fully characterized with both usual techniques such as X-ray diffraction, scanning electron microcopy and N2 adsorption and more advanced tools such as small-angle X-ray scattering (SAXS) and transmission electron microscopy. The different parameters obtained from all these characterization methods (d002, specific surface area, radius of gyration and crystallite size) can be linked to the electrochemical performances as indicated in the figure. Samples pyrolysed from 1300°C to 1600°C showed a reversible capacity equal to 300 mAh.g-1 at C/10 rate (where C=372 mA.g-1) with an excellent stability in cycling and a very good initial coulombic efficiency reaching 84%. The second part of the presentation aims to deeper understand sodium insertion mechanisms in these disordered structures. To distinguish the different mechanisms hard carbons are discharged at different potentials and analyzed with SAXS and impedance spectroscopy.

Experimental Investigation of the Biomass Catalytic Pyrolysis Process to Produce the Combustible Gases with the High Calorific Value

The study is devoted to the low-temperature catalytic pyrolysis of biomass. The pyrolysis of peat was conducted using natural aluminosilicates and synthetic zeolites. It was found that the pore size of the mineral strongly affects the catalytic activity and provides the processing of the hydrocarbons forma-tion reactions. Bentonite clay was found to be the most effective catalyst for the biomass pyrolysis proc-ess. The use of bentonite clay as an addition to peat allows improving structural (strength, porosity) and sorption characteristics (sorption rate) of the molded compositions and can serve as a catalyst dur-ing its subsequent thermal conversion. The amount of gases obtained using natural aluminosilicate as a catalyst increased by 2 times compared to the non-catalytic process. The calorific value of the prod-ucts obtained was higher due to the light hydrocarbons formation. Copyright © 2015 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).

TG–FTIR-MS study of pyrolysis products evolving from peat

Thermal characteristics and gas compositions during peat pyrolysis under helium atmosphere were investigated using the TG–FTIR-MS coupling technique. The majority of gas products were released during the decomposition temperature of 150–550°C, resulting in about 60% mass loss of peat. The main gas species detected during 150–400°C were CO2, CO, CH4, C2H6, HCOOH, CH3CH2COOH, C4H8 and CH2CHCHO. From 400°C to 550°C, some aromatic hydrocarbons were identified, including benzaldehyde, phenol, benzoic acid and toluene. The release of CO2, CO, CH4 and some aromatic hydrocarbons over 550°C provided the evidence of char pyrolysis. A five-step pyrolysis scheme including water evaporation, hemicellulose, cellulose and lignin degradation, and char pyrolysis was used to simulate peat decomposition process in inert atmosphere. The well agreement between the calculated and experimental curves indicated that major aliphatic gases were derived from hemicellulose and cellulose pyrolysis, while aromatic hydrocarbons were mainly from lignin and char pyrolysis. This work provides a deep insight into the utilization of peat for gaseous biofuels.

Characterisations and Electrochemical Performances of Hard Carbons in Sodium Ion Batteries

Nowadays, lithium ion (Li-ion) batteries are present in many applications such as mobile phones, computers, hybrid electric (HEV) and electric (EV) vehicles. However abundance, cost and especially accessibility of lithium may bring some issues for Li-ion development in the future [1]. This leads the scientist community to go back to sodium ion battery research, which stopped because of Li ion battery success in the 80’s. Sodium seems to be an interesting alternative to lithium because of its abundance and availability. However, in order to be competitive to other technologies in stationary domain, for instance, capacity, rate capability and cycle life should be improved [2]. Carbons have been extensively studied in the literature as Na-Ion anodes: hard carbons, carbon black, carbon nanospheres, carbon fibers and graphene. Carbon nanotubes made from polyaniline pyrolysis showed interesting performances. A reversible capacity of 250 mAh/g at a current density of 50 mA/g was obtained with 82% of capacity retention after 400 cycles. However the initial coulombic efficiency remains very low (around 50%) [3]. Ding et al. [4] tested carbon made from peat pyrolysis as anode for Na ion batteries. They obtained a reversible capacity of 255mAh/g after 200 cycles with a current density equal to 50 mA/g. In our study, hard carbons (HC) were made from cellulose. Different final pyrolysis temperatures were studied from 700°C to 1600°C. Characterisation methods such as Small Angle X ray Scattering (SAXS) measurements; isotherms and Transmission Electron Microscopy (TEM) were performed in order to understand the impact of pyrolysis temperature on carbon structure. This parameter plays a major role on external and internal porosities. Different electrochemical tests were performed to study stability and rate capability of the samples. Figure 1 shows the cycling performances of the sample pyrolysed at 1400°C. In our presentation, we propose to highlight the characterisations performed on these hard carbons. TEM images could clearly show the different graphene sheet arrangements. With the tests performed on Na//HC cells, we will try to correlate hard carbon structure to electrochemical performances. Perspectives on future studies will be also exhibited.

Energetic potential and kinetic behavior of peats

Investigations were conducted with the aim to improve the energetic characterization of peats with different geological origin, hydrology, and botanical composition. Special attention was paid to the effects and kinetics of thermal treatment of peat decomposition in an oxidative atmosphere. Experiments were carried out using thermogravimetry, differential scanning calorimetry, and a calorimetric bomb. The present study shows that thermal decomposition process consists in a devolatilization step between 473 and 650 K and a combustion step between 650 and 773 K. Thermochemical properties (i.e., degree of decomposition, ultimate analysis, and heating value) were determined for each sample and correlated to thermal behavior. Based on the experimental results, the kinetic parameters for pyrolysis and combustion of boreal peat were estimated using a three-step model. The kinetic triplet of each reaction was estimated using the hybrid kinetic method Cancellieri et al. (Thermochim Acta 438:41–50, 2005). These results will assist in the development of an energetic classification of peat fuels.

Autothermal pyrolysis of peat in conditions of free movement in layer

Modern trends of energy saving provide actuality of research. Ability to implement pyrolyze in autothermally mode was investigated. Method of research is a physical experiment. As a result of research are obtained: dependency diagram as the thickness layer of the angle inclination of working surface, dependency diagram as the fall ash of the angle inclination of working surface, dependency diagram as the moving rate of peat of the pyrolysis temperature with different inclinations of working surface.

Calculation Method of Kinetic Constants for the Mathematical Model Peat Pyrolysis

Relevance of the work is related to necessity to simplify the calcula- tion of kinetic constants for the mathematical model peat pyrolysis. Execute transformations of formula Arrhenius law. Degree of conversion is expressed in terms mass changes of sample. The obtained formulas help to calculate the ki- netic constants for any type of solid organic fuels

Some results of mathematical simulation of the process of peat ignition

A formulation and numerical solution of the problem about peat layer ignition as a result of the action of a creeping fire bed are proposed based on a mathematical model of a porous reactive medium. Ignition of the initial reagent is shown to be determined by processes of drying, peat pyrolysis, oxidation of carbon oxide, and moisture content. The results of the numerical solution are compared with experimental data, and an estimate of the mass content of combustion products contaminating the atmosphere is presented.

Development of a new peat-based oil sorbent using peat pyrolysis

The growing use and transport of crude oil and oil products has led to increasing numbers of oil spillages of various scales. Oil sorbents have been extensively used for remediation of the consequences of such accidents. The aim of this study is to investigate the possible use of peat and its thermal treatment products for oil sorption. Peat as an oil sorbent has poor buoyancy characteristics, relatively low oil sorption capacity and low hydrophobicity. However, thermal treatment (low-temperature pyrolysis and synthesis of peat-based activated coal) helps to significantly improve its sorptive characteristics. Peat is a potential material for oil sorption because it has such advantages as low cost, biodegradability and relatively high parameters of specific surface area and porosity. The processes and structural changes taking place during low-temperature pyrolysis have been studied by means of IR spectroscopy, thermogravimetry and scanning electron microscopy.

Combined catalytic pyrolysis of peat and petroleum-containing wastes

The mutual effect of peat and petroleum-containing wastes on the degree of conversion of their mixture during pyrolysis, and also the effect of bentonite clay on pyrolysis of the mixture are investigated. The temperature of the process and catalyst content were determined in the course of previous investigations. A sample mixture of peat and petroleum sludge in a 1:1 ratio was used for the investigation. The content of petroleum products in the petroleum sludge amounted to 20% of the mass of the sludge, the catalyst content was 5% of the mass of the mixture, the process was carried out in a nitrogen atmosphere, and the temperature of the process was 500°C. During the course of the experiments, the masses of the solid, liquid, and gaseous products were determined, and the gaseous mixture of pyrolysis products was also subjected to qualitative and quantitative analysis. The gaseous products were analyzed using gas chromatography in accordance with a method outlined in an external standard.

Mathematical modeling of the initiation and spread of peat fires

We propose a new statement and a numerical solution of the problem on ignition of a peat bed as a result of the action of the nucleation site of a low fire on the basis of the mathematical model of a porous reactive medium. It has been obtained that at moderate temperatures (T 2 ≤ 750 K) the smoldering of the original reactant is determined by the processes of heat and mass exchange with the nucleation site of the forest fire, drying, and pyrolysis of peat, as well as by the oxidation reaction of carbon oxide, the peat height, and the thickness of the water stratum under its bed.

Experimental industrial plant for catalytic pyrolysis of biomass

An experimental plant for optimization of production regimes for the pyrolysis of biomass and wastes of organogenic origin with an output of 500 kg/day is proposed. All equipment of the plant is grouped in a single production module. Processes involving catalytic pyrolysis of peat and refined products of used truck tires are tested on the plant for the production of gaseous fuel. The experimental industrial tests demonstrate the plant’s high efficiency, and the expediency of catalytic pyrolysis for utilization of organogenic wastes.

Characterization of gases and solid residues from closed system pyrolysis of peat and coals at two heating rates

Closed system gold-tube pyrolysis experiments were performed on a peat and two coals (TY: Ro=0.51%; SX: Ro=0.94%) at temperatures ranging from 337 to 600°C and a pressure of 50MPa with heating rates of 2 and/or 20°C/h. Solid reaction residues were analyzed microscopically. Yields and chemical and isotopic compositions of the generated gases were also determined. All three samples had similar thermal evolution pathways. With increasing heating temperature, vitrinite reflectances (VRr) of the residues increased linearly from 0.72% to 4.50%. This increase was lesser for the sample with a higher hydrocarbon generation potential and at faster heating rates. Gas compositions are dominated by CO2 and CH4 throughout the experimental process. Total gas and CH4 yields gradually increase with pyrolysis temperature for all samples. The carbon isotopic compositions of CH4 generated from the peat are lighter than those from the coals. The δ13CCH4 values exhibit a generic evolution pattern which the initial CH4 is isotopically heavy, then becomes lighter at moderate temperatures, and finally becomes heavier again. Methane produced from the samples at low heating rate has higher transformation ratio than that at high heating rate under the same temperature, so tends to be isotopically heavy after pyrolysis temperature of more than 408°C.

Characteristics and Kinetics of Forest Peat Pyrolysis

Peat smoldering is one of the main combustion modes of forest ground fires. Research into the pyrolysis kinetics of peat is an essential step in studying the peat smoldering mechanism and ground fire behavior. We measured the elemental composition of one typical peat sampled from the northeast forest zone of China by means of spectrofluorometry and studied the pyrolysis characteristics of peat with thermogravimetry-differential thermal analysis (TG-DTA). Results show that the peat sample is composed of more than 45 elements. The pyrolysis process of peat may be divided into three stages, i.e., dehydration, organic matter pyrolysis and mineral decomposition. Because organic matter pyrolysis played an important role in peat smoldering, the pyrolysis kinetics of organic matter was determined. Using thermal kinetic analysis theory and optimization methods, the model that three-component react parallelly was established to describe the scheme of peat pyrolysis. We found that the scheme containing three-parallel-reactions could describe the pyrolysis kinetics very well.

Peat semicoking and hydrocracking

This work deals with thermochemical conversion of peat into solvent-soluble oil and volatile gaseous products by using pyrolysis and catalytical hydrocracking methods. Distribution of liquid compounds between solubilized in water, benzene, and in acetone was determined and as a result the oil yield as total solubles was calculated. Chromatographic and FTIR-spectroscopic methods were used to characterize the composition of conversion products. Investigation of peat pyrolysis regularities in comparison with those of oil shale by using Rock-Eval analysis demonstrated essential differences between peat and oil shale as pyrolysis feedstock. As a result of hydrocracking the total oil yield was increased more than twice compared with that of semicoking, 29.8 and 13%, respectively. Hydrocracking and semicoking led to significant deoxygenation of oil and solid residual conversion products via oxygen removal as carbon dioxide and water. Hydroxyl-, carboxyl-, carbonyl- and other oxygen functionalities in peat initial matter being hydrocracked and modified, the oil was characterized by elevated hydrocarbon content and decreased that of polar oxygen compounds. As the oxygen content of the product decreases, the energy content significantly increases and peat oil, particularly its hydrophobic fractions, can be used for synthetic liquid fuel.