Experimental investigation of pyrolysis process of woody biomass mixture

This paper describes an experimental investigation of pyrolysis of woody biomass mixture. The mixture consists of oak, beech, fir, cherry, walnut and linden wood chips with equal mass fractions. During the experiment, the sample mass inside the reactor was 10 g with a particle diameter of 5-10 mm. The sample in the reactor was heated in the temperature range of 24-650℃. Average sample heating rates in the reactor were 21, 30 and 54 ℃/min. The sample mass before, during and after pyrolysis was determined using a digital scale. Experimental results of the sample mass change indicate that the highest yield of pyrolytic gas was achieved at the temperature slightly above 650℃ and ranged from 77 to 85%, while char yield ranged from 15 to 23%. Heating rate has sig- nificant influence on the pyrolytic gas and char yields. It was determined that higher pyrolysis temperatures and heating rates induce higher yields of pyrolytic gas, while the char mass reduces. Condensation of pyrolytic gas at the end of the pyrolysis process at 650℃ produced 2.4-2.72 g of liquid phase. The results obtained represent a starting basis for determining material and heat balance of pyrolysis process as well as woody biomass pyrolysis equipment.     

Bio-oil Production from an Oilseed By-product: Fixed-bed Pyrolysis of Olive Cake

Abstract

A study of pyrolysis of olive cake at the temperature range from 400°C to 700°C has been carried out. The experiments were performed in a laboratory scale tubular reactor under nitrogen atmosphere. The yields of derived gases, liquids, and char were determined in relation to pyrolysis temperature and sweeping gas flow rates, at heating rates of about 300°C min^?1. As the pyrolysis temperature was increased, the percentage mass of char decreased whilst gas product increased. The oil products increased to a maximum value of ～39.4 wt% of dry ash free biomass at a pyrolysis temperature of about 550°C in a nitrogen atmosphere with flow rate of 100 mL min^?1 and with a heating rate of 300°C min^?1. Results showed that the bio-oil obtained under the optimum conditions is a useful substitute for fossil fuels or chemicals.     

Fixed-Bed Pyrolysis of Hazelnut (Corylus Avellana L.) Bagasse: Influence of Pyrolysis Parameters on Product Yields

Fixed-bed slow pyrolysis experiments have been conducted on a sample of hazelnut bagasse to determine particularly the effects of pyrolysis temperature, heating rate, particle size and sweep gas flow rate on the pyrolysis product yields. The temperature of pyrolysis, heating rate, particle size and sweep gas flow rate were varied in the ranges 350–550° C, 10 and 50° C/min, 0.224–1.800 mm and 50–200 cm³/min, respectively. Under the various pyrolysis conditions applied in the experimental studies, the obtained char, liquid, and gas yield values ranged between 26 and 35 wt%, 23 and 34.40 wt%, and 25 and 32 wt%, respectively. The maximum biooil yield of 34.40% was obtained at the final pyrolysis temperature of 500°C, with a heating rate of 10° C/min, particle size range of 0.425–0.600 mm and a sweep gas flow rate of 150 cm³/min.     

Olive residues (cuttings and kernels) rapid pyrolysis product yields and kinetics

A study of pyrolysis of olive residues (cuttings and kernels) at a temperature range from 300 to 600°C, has been carried out. The experiments were performed in a captive sample reactor at atmospheric pressure under helium. The yields of the derived gases, pyrolytic liquids and char were determined in relation to pyrolysis temperature, at heating rates of about 200°C/s.As the pyrolysis temperature was increased the percentage mass of char decreased whilst gas and oil products increased. The oil products increased to a maximum value of ∼30 wt% of dry biomass at about 450–550°C. The major gaseous products are CO and CO₂.A simple first order kinetic model has been applied to the evolution of total losses and gases. Kinetic parameters have been estimated and compared with other reported similar data.     

Experimental study of the pyrolysis of waste bitumen for oil production

This work focuses on bitumen slow pyrolysis. Mass and energy yields of oil, solid and gas were obtained from pyrolysis experiments using a semi-batch reactor in a nitrogen atmosphere, under three non-isothermal conditions (maximum temperature: 450 °C, 500 °C and 550 °C). The effect of temperature on the product yields was discussed. The gas compositions were analysed using gas chromatography (GC) and the heating value of oil and solid residue was also measured. Using a thermo-gravimetric analyser, kinetic parameters were evaluated through Ozawa-Flynn-Wall (OFW) method. Results showed that oil yield is maximum at 500 °C (50%). Moreover, gas yield increased with increasing pyrolysis temperature from 18% to 36%. On the other hand, solid yield showed an opposite trend: it decreased from 39% to 32%. As regard energy yields, they showed a similar trend with the mass ones. H_2, CH₄, C₂H₄, C₂H₆ and C₃H₈ are the main components of the produced gas phase. It has been noticed that the recovery of bitumen to liquid oil through pyrolysis process had a great potential since the oil produced had high calorific value comparable with commercial fuels.     

Energy production from the pyrolysis of waste biomasses

Pyrolysis of waste biomasses was carried out at the temperatures of 450 and 500°C by heating at 5°C min^?1. Products were collected from emitted gases in a nitrogen purge stream; condensable liquids in the gases were collected by condensation. Gaseous, condensed liquid products and residual solids were collected and analyzed. Condensates were extracted with ether to recover the bio oils (BOs). The maximum liquid yield was obtained from the pyrolysis of soybean oil cake (SBOC) at 500°C with a yield of 60% ca. The BO was higher in the case of SBOC than that of sunflower oil cake (SFOC) at the temperatures of 450 and 500°C. With increasing temperature, bio char yield from the pyrolysis of SFOC decreased, while the liquid yield increased. The increase in temperature did not significantly affect the product distribution for the pyrolysis of SBOC. The compositions of BOs were similar for both SBOC and SFOC. Phenols, phenol derivatives including guaiacols and alkyl‐benzenes were the most common and predominant in BOs from both the pyrolysis of SBOC and SFOC. Carbon dioxide was the major gas product for both SBOC and SFOC. Copyright © 2008 John Wiley & Sons, Ltd.     

Energy Applications of Biomass: Pyrolysis of Apricot Stone

Apricot stone (Prunus armeniaca L.) was pyrolyzed in a directly heated fixed-bed reactor under nitrogen atmosphere. Effects of sweeping gas flow rates and pyrolysis temperature on the pyrolysis of the biomass were also studied. Pyrolysis runs were performed using reactor temperatures between 400°C and 700°C with heating rate of about 300°C min^?1. As the pyrolysis temperature was increased, the percentage mass of char decreased while gas product increased. The product yields were significantly influenced by the process conditions. The bio-oil obtained at 550°C, at which the liquid product yield was maximum, was analyzed. It was characterized by Fourier transform infrared spectroscopy (FT-IR). In addition, the solid and liquid products were analyzed to determine their elemental composition and calorific value. Chemical fractionation of bio-oil showed that only low quantities of hydrocarbons were present, while oxygenated and polar fractions dominated.     

Waste pyrolysis and generation of storable char

Sustainable cities require the generation of energy from waste that cannot be economically reused or recycled. This study focuses on slow pyrolysis that can generate a high yield of char along with liquid and gas products from waste. Char is high in energy content, storable and transportable with low cost so that it can be used as an intermediate medium for high efficiency energy conversion. Pre‐processed municipal waste pellets, wood and grass were pyrolysed in a batch type reactor for a final temperature ranging from 350 to 700°C, and the char products were characterized. The mass yields of char ranged from 55 to 20% for the tested temperature range, recovering 70–30% of energy and 62–30% of carbon in the raw material. The gross calorific value of char was 30–35 MJ kg^?1 on a dry ash free basis. The ash content of raw materials was a key parameter for the quality of char, since its proportion increased by 2–4 times in char depending on the mass yield. A significant amount of volatile metals such as Hg, As and Pb in the waste sample was evaporated at 500°C. Therefore, evaporation of volatile metals was another important parameter in determining the pyrolysis temperature and fuel residence time. The char did not show significant morphological change in the tested range of temperatures. It was concluded that slow pyrolysis of waste for char production should be performed below 500°C in order to increase the energy yield and also to reduce the evaporation of heavy metals. Copyright © 2006 John Wiley & Sons, Ltd.     

松木颗粒热解与高温蒸汽气化半焦产率及形貌特征分析

以成型松木颗粒为原料,进行低温热解,研究了热解温度和升温速率对生成的松木半焦产率及官能团的影响。以试验得到的松木半焦进行蒸汽气化试验,对比分析了温度对半焦重整气化形貌特征、比表面积和平均孔径的影响。研究表明：随着热解温度升高,松木半焦脂肪族结构峰消失转化为烃等小分子物质及气化气,进而降低半焦产率。升温速率升高,半焦产率呈先下降后升高的趋势,在800℃升温速率为30K/min时半焦产率最低。不同温度热解和蒸汽气化对比试验表明,温度相对较低时（500℃）热解和蒸汽气化半焦孔隙结构相近,随着温度的升高,蒸汽气化半焦结构发生明显变化,900°C时出现了更小的孔道结构且比表面积增加明显。蒸汽引入使松木半焦和水蒸气发生热解反应的同时发生了脱氢反应,气化半焦形貌出现熔融和烧结现象。     

Kinetic characteristics of in-situ char-steam gasification following pyrolysis of a demineralized coal

This study aims to examine the char-steam reactions in-situ, following the pyrolysis process of a demineralized coal in a micro fluidized bed reactor, with particular focuses on gas release and its kinetics characteristics. The main experimental variables were temperatures (925 °C?1075 °C) and steam concentrations (15%–35% H₂O), and the combination of pyrolysis and subsequent gasification in one experiment was achieved switching the atmosphere from pure argon to steam and argon mixture. The results indicate that when temperature was higher than 975 °C, the absolute carbon conversion rate during the char gasification could easily reach 100%. When temperature was 1025 °C and 1075 °C, the carbon conversion rate changed little with steam concentration increasing from 25% to 35%. The activation energy calculated from shrinking core model and random pore model was all between 186 and 194 kJ/mol, and the fitting accuracy of shrinking core model was higher than that of the random pore model in this study. The char reactivity from demineralized coal pyrolysis gradually worsened with decreasing temperature and steam partial pressure. The range of reaction order of steam gasification was 0.49–0.61. Compared to raw coal, the progress of water gas shift reaction (CO + H₂O ? CO₂ + H₂) was hindered during the steam gasification of char obtained from the demineralized coal pyrolysis. Meanwhile, the gas content from the char gasification after the demineralized coal pyrolysis showed a low sensitivity to the change in temperature.     

The influence of temperature and heating rate on the slow pyrolysis of biomass

The slow pyrolysis of biomass in the form of pine wood was investigated in a static batch reactor at pyrolysis temperatures from 300 to 720°C and heating rates from 5 to 80 K min⁻¹. The compositions and properties of the derived gases, pyrolytic oils and solid char were determined in relation to pyrolysis temperatures and heating rates. In addition, the wood and the major components of the wood—cellulose, hemicellulose and lignin—were pyrolysed in a thermogravimetric analyser (TGA) under the same experimental conditions as in the static batch reactor. The static batch reactor results showed that as the pyrolysis temperature was increased, the percentage mass of solid char decreased, while gas and oil products increased. There was a small effect of heating rate on product yield. The lower temperature regime of decomposition of wood showed that mainly H₂O, CO₂ and CO were evolved and at the higher temperature regime, the main decomposition products were oil, H₂O, H₂, hydrocarbon gases and lower concentrations of CO and CO₂. Fourier transformation infra-red spectroscopy and elemental analysis of the oils showed they were highly oxygenated. The TGA results for wood showed two main regimes of weight loss, the lower temperature regime could be correlated with the decomposition of hemicellulose and the initial stages of cellulose decomposition whilst the upper temperature regime correlated mainly with the later stages of cellulose decomposition. Lignin thermal decomposition occurred throughout the temperature range of pyrolysis.     

Bio‐oil production from rapid pyrolysis of cottonseed cake: product yields and compositions

Fixed‐bed fast pyrolysis experiments have been conducted on a sample of cottonseed cake to determine the effects of pyrolysis temperature, heating rate and sweep gas flow rate on pyrolysis yields and chemical compositions of the product oil. The liquid products and the subfractions of pentane soluble part were characterized by elemental analysis, FT‐IR spectroscopy, ¹H‐NMR spectroscopy and pentane subfraction was analysed by gas chromatography. The maximum oil yield of 34.8% was obtained at final temperature of 550°C with a heating rate of 700°C min^?1 and nitrogen flow rate of 100 cm³ min^?1. Chromatographic and spectroscopic studies on bio‐oil have shown that the oils obtained from cottonseed cake can be used as a renewable fuel and chemical feedstock. Copyright © 2005 John Wiley & Sons, Ltd.     

Impact of fast and slow pyrolysis on the degradation of mixed plastic waste: Product yield analysis and their characterization

This work primarily investigated the pyrolysis of post-consumer mixed plastic wastes during slow pyrolysis (non-isothermal) in a batch reactor to assess the effect of different heating rates on the product yield and its composition. The effect of residence time during fast pyrolysis (Isothermal) in Pyro-GC was also investigated. Initially, TG analysis was performed to investigate the degradation temperature range at different heating rates of 5, 10, 20 and 40 °C/min. Two different heating rates of 10 and 20 °C/min were selected for examining the effect on products such as oil and gases (H₂, CO, CO₂ and C₁-C₆ hydrocarbons) during slow pyrolysis. The oil obtained at higher heating rate had higher density (0.743 kg/m³) while the amount of residue decreased with the increase in heating rate. Also, the effect of residence time during fast pyrolysis was investigated using Pyro-GC at 500 °C for the product formation. It was observed that an optimum residence time of 10sec was favourable for the higher production of lower hydrocarbons (C₁-C₃) and less production of heavier hydrocarbons (C₆). This work represents the combined analysis of fast and slow pyrolysis and their impact on the product yield. Also, the effect of heating rate on non-isothermal condition and the effect of the residence time of volatiles in isothermal condition was analysed and reported.     

Pyrolysis of pressure-sensitive adhesive wastes in a fixed-bed reactor

Pyrolysis of pressure-sensitive adhesive (PSA) wastes have been investigated in a fixed-bed reactor with a heating rate of 20°C/min. PSA pyrolysis mainly occurs between 300 and 600°C. The maximum liquid yield was obtained at 550°C with a yield of 55.69%. Liquid product can be used as fuel or raw material for purifying 2-ethyl-1-hexanol, dehydroabietic acid, 2,4-dimethyl-1-heptene, and styrene. The main composition in gas is CO and CO₂, followed by CH₄ and H₂. High content of ash in char limits the application in fuel, but might be used as an adsorption material after upgrading.     

Energy recovery by fast pyrolysis of pre-treated trommel fines derived from a UK-based MSW material recycling facility

In this experimental study, a physically pre-treated trommel fines feedstock, containing 44 wt% non-volatiles (ash and fixed carbon) and 56 wt% volatile matter (dry basis), was subjected to fast pyrolysis to recover energy from its organic load, using a 300 g h⁻¹ bubbling fluidized bed (BFB) fast pyrolysis rig. A physical pre-treatment method (including crushing, grinding and sieving) was used to prepare a 0.5–2 mm sized trommel fines feedstock to make it suitable for fast pyrolysis in the BFB reactor. Experimental results from the fast pyrolysis process showed that the highest yield of organic liquid was obtained at around a temperature of 500 °C. However, both char and gas yields increased dramatically at temperatures above 500 °C, as a result of enhanced cracking of organic vapours, which reduced the yield of liquid products. Overall, energy recovery from the pyrolysis products (liquid and gas products as well as char pot residues) ranged from 63 to 70%, generally increasing with temperature. A large proportion of the high ash content (36 wt%) of the feedstock was found in the char pot (>62%), while smaller proportions were found in the reactor bed and some liquid products. The char pot ash residues composed mostly of non-hazardous earth materials and may be applied in bulk construction materials e.g. cement manufacture. Although, there was no problem with the pyrolysis rig during 1 h of operation, longer periods of operation would require periodic removal of accumulated solid residues and/or char pot modification to ensure continuous rig operation and process safety.     

Manufacturing gaseous products by pyrolysis of microalgal biomass

Algal biomass is considered as an alternative raw material for biofuel production. The search for new types of raw materials including high-energy types of microalgae remains relevant, since the share of motor fuels in the world energy balance remains consistently high (about 35%) with the oil price characterized by high volatility. The authors have considered the advantages of microalgae as raw materials for fuel production. Biochemical and thermochemical conversion are proposed as technologies for their processing. The paper presents the results of the study on the pyrolysis of the biomass of the blue-green microalgae/cyanobacterium Arthrospira platensis rsemsu 1/02-P clonal culture from the collection of the Research Laboratory of Renewable Energy Sources of the Lomonosov Moscow State University. The experimental investigation on the pyrolysis process of microalgal biomass has been carried out with the experimental setup made at the Institute of High Temperatures RAS in pure nitrogen 6.0 to create an oxygen-free medium with a linear heating rate of 10°С/min from room temperature to 1,000°С. The entire pyrolysis process has proceeded in the endothermic region. The specific values for solid residue, pyrolysis liquid and gaseous products have been experimentally determined. The following products have been manufactured by pyrolysis of microalgal biomass weighing 15 g: 1) char with a solid residue mass of 2.68 g, or 17.7% of MAB initial mass (while 9.3% of MAB initial mass has remained in the reactor); 2) pyrolysis liquid with a mass of 3.3 g, or 21.9% of initial mass; 3) noncondensable pyrolysis gases, 1.15 L. The specific volumetric gas yield (amount of gas released from 1 kg of RM) has amounted to 0.076 nm³/kg.In the paper, the analysis of the composition and specific volumetric yield of non-condensable pyrolysis gases produced in the pyrolysis process depending on temperature has been carried out. It is shown that the proportion of high-calorific components of the gas mixture (hydrogen, methane and carbon monoxide) increases with the temperature increase. The heating value assessment for the mixture of these gases has been performed as well.     

Pyrolysis characteristics of RDF and HPDE blends with biomass

The main objective of this work was to study refuse-derived fuels (RDF) and high-density polyethylene (HDPE) upgrading by pyrolysis of blends of these materials with wood. The study considered three operational conditions: cracking temperature, heating rate, and different wt.% of RDF and HDPE. The results demonstrate that the cracking temperature of 500 °C and the faster heating rates increased the liquid yield for RDF blends. On the other hand, HDPE blends favor gas production at 550 °C and faster heating rates, which enhance the process operativity because polymeric materials generate waxes and are reduced beneath such conditions. Finally, produced gas LHV increases as RDF and HDPE were added. For example, the LHV of the produced gas only with wood at 550 °C and 20 °C/min was 10.34 MJ/m³ and with 25 wt% HDPE was 14.82 MJ/m³.     

Fuel gas production from dusty tar pyrolysis

Dusty tar is an undesired product obtained from a coal pyrolysis/combustion system. Thermal conversion of dusty tar into fuel gas was studied with a fixed-bed reactor. It is found that C₂-C₅ hydrocarbons are mainly derived from the cracking of long-chain aliphatics, while CH₄ from the decomposition of long-chain aliphatics and alkyl-substituted aromatic chemicals. The yield of the gas product increases monotonously, but the heating value of gas gradually decreases as temperature increases from 400 to 950°C. Decomposition of chemicals with a boiling point over 360°C contributes to 50–90% C₁-C₅ hydrocarbons and CO_x when pyrolysis temperature is lower than 600°C.     

Pyrolysis of giant mullein (Verbascum thapsus L.) in a fixed-bed reactor: Effects of pyrolysis parameters on product yields and character

Slow pyrolysis of giant mullein (Verbascum thapsus L.) stalks have been carried out in a fixed-bed tubular reactor with (Al₂O₃, ZnO) and without catalyst at four different temperatures between 400 to 550°C with a constant heating rate of 50°C/min and with a constant sweeping gas (N₂) flow rate of 100 cm³/min. The amounts of bio-char, bio-oil, and gas produced were calculated and the compositions of the obtained bio-oils were determined by gas chromatography-mass spectrometry. The effects of pyrolysis parameters, such as temperature and catalyst, on the product yields were investigated. The results show that both temperature and catalyst have significant effects on the conversion of Verbascum thapsus L. into solid, liquid, and gaseous products. The highest liquid yield of 40.43% by weight including the aqeous phase was obtained with 10% zinc oxide catalyst at 500°C temperature. Sixty-seven different products were identified by gas chromatography-mass spectrometry in the bio-oils obtained at 500°C temperature.     

Product distribution from solar pyrolysis of agricultural and forestry biomass residues

Solar pyrolysis of pine sawdust, peach pit, grape stalk and grape marc was conducted in a lab-scale solar reactor for producing fuel gas from these agricultural and forestry by-products. For each type of biomass, whose lignocellulose components vary, the investigated parameters were the final temperature (in the range 800°C–2000 °C) and the heating rates (in the range 10–150 °C/s) under a constant sweep gas flow rate of 6 NL/min. The parameter influence on the pyrolysis product distribution and syngas composition was studied. The experimental results indicate that the gas yield generally increases with the temperature and heating rate for the various types of biomass residues, whereas the liquid yield progresses oppositely. Gas yield as high as 63.5wt% was obtained from pine sawdust pyrolyzed at a final temperature of 2000 °C and heating rate of 50 °C/s. This gas can be further utilized for power generation, heat or transportable fuel production.