Liquid Tar Research Articles

Pyrolytic mechanisms of typical organic components of sewage sludge in the presence of CaO: Polysaccharides, proteins, and lipids

The addition of CaO could facilitate the conversion of sewage sludge (SS) from waste to high-purity syngas. The pyrolytic characteristics of SS are a comprehensive manifestation of polysaccharides, proteins, and lipids, while the influence of CaO on their pyrolytic characteristics is rarely reported. This study conducted a thorough investigation into the pyrolytic mechanism of starch, protein, and lipid in the presence of CaO by analysing their thermal behavior, gaseous products, liquid tar, and residual char. The findings from TGA, GC, GC–MS, and FT-IR analysis indicate that the addition of CaO catalytically lowers the pyrolysis temperature of starch, protein, and lipid components and promotes their conversion into small molecules, resulting in increased syngas production. Moreover, the combination of char with the carbonation and calcination cycle of CaO leads to a significant boost in syngas (H2 and CO) yield, with up to 3 and 10 times increase from starch and protein, respectively, and a higher syngas selectivity of up to 65 %. The study also identifies those polysaccharides and proteins are the primary sources of syngas. This study can provide further insight into SS pyrolysis for syngas production in the presence of CaO and the necessary parameters to predict the pyrolysis behavior of SS in industrial applications.

Research on the influence of sequential isopropanolysis liquefaction on the composition of liquid tars and physicochemical structure evolution of renbei lignite

A green and efficient sequential isopropanolysis liquefaction approach was reported to convert lignite into high yield of liquid tars (LTs) as fuels/value-added chemicals in this research, but its influence on the molecular structure composition of LTs and physicochemical structure evolution of lignite still received little attention. The sequential isopropanolysis of RB lignite was performed at 240, 280, and 320 °C in isopropanol for obtaining three LTs (LT240 °C, LT280 °C, and LT320 °C) and three residues (R240 °C, R280 °C, and R320 °C). Among three LTs, phenols represented the highest relative content value, accounting for 72.54, 90.48, and 84.83%, respectively, and mainly can be divided into phenol and (C1–C8)-phenol. There was hydrocarbon, Oy (y = 1–5), NOy (y = 0–2), N2Oy (y = 0–2), N3Oy (y = 0–1), NxSz (x = 0–1, z = 1–2), and SNxOy (x = 1–2, y = 1–2) class species existed in three LTs on the basic of the analysis with quadrupole exactive orbitrap mass spectrometer (QEOTMS). Notably, O1 and O2 class species were the more abundant components in three LTs. The cleavage of C–O bridged bonds should be the main reaction path and the graphitization degree of residues significantly enhanced. The main pyrolysis zone of residues shifted to higher temperature area and the pyrolysis activation energy of stage II increased.

PRODUCTION AND FUNGICIDAL ACTIVITY ASSESMENT OF WOOD-WASTE LIQUID SMOKE

Liquid smoke is known to contain compounds that can control plant disease pathogens. This study aims to produce wood-waste liquid smoke and determine its effectiveness as a fungicide on plant pathogens. This research was conducted in two experimental stages, namely: (i) in vitro test as a preliminary test of the effectiveness of teak waste liquid smoke at concentrations of 0, 0.5, 1, 1.5, 2, and 2.5%; and (ii) in vivo test was arranged in randomized block design consisting of seven levels of liquid smoke concentration, namely 0, 1, 2, 3, 4, 5, and 6%, each of which was repeated four times. The results showed that the pyrolysis of 1 kg of wood waste was produced with the proportions of liquid smoke, charcoal and tar, respectively: 312 mL, 31 g, 367 g and the uncondensed gases. Treatment of liquid smoke in the in vivo test showed that a concentration of 1 to 2.5% liquid smoke was able to suppress the growth of the pathogenic fungus Sclerotium rolfsii 100%. The treatment of liquid smoke in the in vivo test showed an effect on inhibition of the growth diameter of fungal colonies, suppressing the disease occurance, and suppressing the lesion diameter.

A cost-effective strategy for metal recovery from waste printed circuit boards via crushing pretreatment combined with pyrolysis: Effects of particle size and pyrolysis temperature

The dramatic increase in global generation of e-wastes has become a great challenge for sustainable development, and strategies for efficient and environmental-friendly recycling and disposal of e-waste are of great demand. A cost-effective strategy of crushing pretreatment combined with pyrolysis to recover metals from waste printed circuit boards (WPCBs) has been developed. Effects of particle size and pyrolysis temperature on metal recovery were explored. The optimal combination of less energy consumption and higher metal recovery was obtained when the pretreated particle size was 4.0 cm and pyrolysis temperature was 330 °C. The Cu and Sn were recovered as zero-valent copper and tin-copper alloy with the recovery efficiency of 92.38 and 99.80 wt%, respectively. Brominated pollutants are easily controlled when pretreated particle size is larger than 2.0 cm and pyrolysis temperature is below 400 °C. Under the optimal crushing pretreatment and pyrolysis conditions, the bromine contents in the pyrolysis products of solid residues, liquid tar, and gas were 45.45 wt%, 38.70 wt%, and 15.85 wt%, respectively. The structure of WPCBs was destroyed at 275–525 °C due to decomposition of brominated epoxy resins (BERs), which could be accurately characterized by 8 dominating reactions through pyrolysis kinetics analysis. The main reactions took place at conversion of 0.14 and 0.15, corresponding to a pyrolysis temperature of 306–342 °C. Thus, the interlayer bonding force of WPCBs significantly decreased, contributing to effective separation of metals in WPCBs.

Experimental study on sulfur-containing products in pressurised oxy-fuel pyrolysis of pulverised coal

Although the contribution of the pressurised oxy-fuel combustion technology for improving energy conversion efficiency and reducing SOx emissions is well recognised, the mechanism of sulfur transformation in the initial pyrolysis step has not yet been elucidated because of the complexity of the pyrolysis process. Clarifying such scientific fundamentals and overcoming technological challenges can effectively advance the implementation of pressurised oxy-fuel combustion technology and realise cleaner production. Herein, the transformation mechanisms of sulfur among solid, liquid, and gaseous states during the pressurised oxy-fuel pyrolysis of pulverised coal were experimentally investigated. The analysis of the gaseous products indicated that the concentration of H2S, the most abundant gaseous product, decreased from 840.3 to 32.1 ppm as the operating pressure increased from 0.1 to 3.1 MPa. Similar trends were observed for CH3SH and SO2. Conversely, COS concentration first increased from 61.4 to 143.4 ppm, after which it decreased to 30.4 ppm, a level similar to H2S concentration. The decreasing sulfur concentration in the volatiles is attributable to the oxidation of low-valence sulfur to form high-valence sulfur and the subsequent absorption by alkali metals in the char residue. The sulfur concentration in liquid tar, which was determined by the competitive reactions of the cracking of heavy hydrocarbons and the polymerisation of light volatiles, first decreased from 6.25 to 3.17 mg/L, followed by an increase to 5.03 mg/L as the operating pressure increased. To further investigate the sulfur transformation, the physicochemical, morphological, and structural properties of pyrolysed char were characterised. The crystal phase, microstructure, average particle size, specific surface area, and surface elemental content of the char affected the distribution and conversion of organic and inorganic sulfur in the char residue. The total sulfur content in the char residue typically increased with operating pressure. Moreover, the effect of operating temperature on the sulfur-containing products was investigated. Based on the experimental results, a binary correlation fitting was applied to predict the various trends in different sulfur-containing gaseous products of pressurised oxy-fuel pyrolysis.

Green and efficient two-step degradation approach for converting Powder River Basin coal into fuels/chemicals and insights into their chemical compositions

A green and efficient two-step degradation approach, including supercritical CO2/ethanol degradation and oxidation in aqueous hydrogen peroxide solution, was reported to convert Powder River Basin coal into fuels/chemicals. In total, 43.5 wt% liquid tar and 23.3 wt% oxidation products were obtained from the two-step degradation. The liquid tar was facilely separated into light oil and asphaltene, with yields of 27.3 wt% and 16.5 wt%, respectively. The first-step degradation has high energy recovery (50%) and low energy consumption ratio (minimum 0.17), indicating an energetic net energy gain. The light oil is a promising feedstock as clean liquid fuels due to its high H/C ratio (1.58) and heating value (34.56 MJ/kg). The asphaltene with lower H/C and O/C ratios but higher aromaticity (0.83) could be a good precursor for carbon materials. The light oil can be upgraded into clean liquid fuels by hydrodeoxygenation or used as feedstock for producing oxygenated chemicals because it is rich in oxygenated components. Phenols and aliphatic esters account for 74.2% of the volatile components in the light oil. High resolution mass spectrometric analysis revealed that the O1–O4 class species are dominant components with relative abundance of 71% in the light oil. Valuable carboxylic acids with total yields of 19.7 wt%, especially alkanedioic and alkanetricarboxylic acids, were produced from oxidation of the scCO2/ethanol degradation residue, which is a promising second-step degradation to utilize the residue. This study provides an efficient coal conversion processes for producing fuels/chemicals and reducing energy consumption and environmental impact.

Enhanced liquid tar production as fuels/chemicals from Powder River Basin coal through CaO catalyzed stepwise degradation in eco-friendly supercritical CO2/ethanol

Developing eco-friendly thermal conversion technologies of coals into fuels/chemicals with minimal environmental impact is highly attractive and significant for efficient coal utilization. CaO catalyzed stepwise degradation at 350–400 °C in eco-friendly supercritical CO2/ethanol (scCO2/ethanol) was carried out to produce high-yield liquid tars as fuels/chemicals from Powder River Basin (PRB) coal. The total yield of the liquid tars increased from 53.9 wt% for non-catalytic stepwise degradation to 60.1 wt% for CaO catalyzed stepwise degradation, with an increase of 6.2 wt%. The resulting ash-free liquid tars are promising raw materials as clean liquid fuels for energy production due to their high H/C ratio (1.16–1.88) and heating values (32.84–35.84 MJ/kg). Compared with non-catalytic stepwise degradation, the energy recovery increases from 62.8% to 71.6% by CaO catalyzed stepwise degradation. More than 75% of the components in the liquid tars were volatilized and/or degraded at temperature <500 °C according to thermogravimetric analysis. The distributions of the functional groups and group components in the liquid tars are similar to each other. Phenols are the most abundant volatile group component in the liquid tars, accounting for about 43% of the volatile components released at 350 °C and 375 °C by CaO catalyzed stepwise degradation. The CaO promoted forming active H+ and CH3CH2O− from ethanol, which readily attacked and cleaved weak -C-O- bonds in the PRB coal, leading to producing more phenols and arenes. Thermal dissociation of the non-covalent interactions especially hydrogen bonds or the cleavage of weak -C-O- in PRB coal could interpret the generation of phenols.

Preliminary assessment of the utilization of durian peel liquid smoke as a natural preservative for mackerel

Background: Durian peel is a type of biomass waste that contains cellulose, hemicelluloses, and lignin. The pyrolysis of these compounds results in production of liquid smoke which can be used as a natural preservative to replace current synthetic preservatives. This research assessed the ability of liquid smoke produced during pyrolysis of durian peel to preserve fish. Methods: Dry durian peel waste underwent batch reactor pyrolysis at 340°C and 380°C, resulting in production of liquid smoke (grade 3), charcoal, and tar. This liquid smoke was then distilled at 190°C to produce grade 1 liquid smoke, which was used to preserve mackerel. The preservation process was conducted by soaking the mackerel samples in liquid smoke at 0.5, 1, 2, and 3% concentration levels followed by observations every 6 hours. Tests to determine the total volatile base nitrogen (TVB-N) content, antibacterial quality of the liquid smoke and organoleptic quality of the fish were conducted in order to assess the preservation properties of the liquid smoke. Results: Tests on the antibacterial effects showed that the liquid smoke inhibited the growth of Escherichia coli and Staphylococcus aureus on fish even at low concentrations. At 54 hours, the TVB-N values remained below 30 mg nitrogen/g, indicating that the fish was still safe for human consumption. Results from the organoleptic tests showed that the concentration of liquid smoke influenced the preservation effects. Conclusions: At a concentration of 2–3%, the fish samples possessed acceptable flavor, taste, color and texture for up to 48 hours of soaking. However, the best conditions were obtained with a 3% concentration of liquid smoke (produced with 340°C pyrolysis), as the fish was still considered acceptable for up to 42 hours.

Preliminary assessment of the utilization of durian peel liquid smoke as a natural preservative for mackerel

Background: Durian peel is a type of biomass waste that contains cellulose, hemicelluloses, and lignin. The pyrolysis of these compounds results in production of liquid smoke which can be used as a natural preservative to replace current synthetic preservatives. This research assessed the ability of liquid smoke produced during pyrolysis of durian peel to preserve fish. Methods: Dry durian peel waste underwent batch reactor pyrolysis at 340°C and 380°C, resulting in production of liquid smoke (grade 3), charcoal, and tar. This liquid smoke was then distilled at 190°C to produce grade 1 liquid smoke, which was used to preserve mackerel. The preservation process was conducted by soaking the mackerel samples in liquid smoke at 0.5, 1, 2, and 3% concentration levels followed by observations every 6 hours. Tests to determine the total volatile base nitrogen (TVB-N) content, antibacterial quality of the liquid smoke and organoleptic quality of the fish were conducted in order to assess the preservation properties of the liquid smoke. Results: Tests on the antibacterial effects showed that the liquid smoke inhibited the growth of Escherichia coli and Staphylococcus aureus on fish even at low concentrations. At 54 hours, the TVB-N values remained below 30 mg nitrogen/g, indicating that the fish was still safe for human consumption. Results from the organoleptic tests showed that the concentration of liquid smoke influenced the preservation effects. Conclusions: At a concentration of 2–3%, the fish samples possessed acceptable flavor, taste, color and texture for up to 48 hours of soaking. However, the best conditions were obtained with a 3% concentration of liquid smoke (produced with 340°C pyrolysis), as the fish was still considered acceptable for up to 42 hours.

Preliminary assessment of the utilization of durian peel liquid smoke as a natural preservative for mackerel

Background: Durian peel is a type of biomass waste that contains cellulose, hemicelluloses, and lignin. The pyrolysis of these compounds results in production of liquid smoke which can be used as a natural preservative to replace current synthetic preservatives. This research assessed the ability of liquid smoke produced during pyrolysis of durian peel to preserve fish. Methods: Dry durian peel waste underwent batch reactor pyrolysis at 340°C and 380°C, resulting in production of liquid smoke (grade 3), charcoal, and tar. This liquid smoke was then distilled at 190°C to produce grade 1 liquid smoke, which was used to preserve mackerel. The preservation process was conducted by soaking the mackerel samples in liquid smoke at 0.5, 1, 2, and 3% concentration levels followed by observations every 6 hours. Tests to determine the total volatile base nitrogen (TVB-N) content, antibacterial quality of the liquid smoke and organoleptic quality of the fish were conducted in order to assess the preservation properties of the liquid smoke. Results: Tests on the antibacterial effects showed that the liquid smoke inhibited the growth of Escherichia coli and Staphylococcus aureus on fish even at low concentrations. At 54 hours, the TVB-N values remained below 30 mg nitrogen/g, indicating that the fish was still safe for human consumption. Results from the organoleptic tests showed that the concentration of liquid smoke influenced the preservation effects. Conclusions: At a concentration of 2–3%, the fish samples possessed acceptable flavor, taste, color and texture for up to 48 hours of soaking. However, the best conditions were obtained with a 3% concentration of liquid smoke (produced with 340°C pyrolysis), as the fish was still considered acceptable for up to 42 hours.

Preliminary assessment of the utilization of durian peel liquid smoke as a natural preservative for mackerel

Background: Durian peel is a type of biomass waste that contains cellulose, hemicelluloses, and lignin. The pyrolysis of these compounds results in production of liquid smoke which can be used as a natural preservative to replace current synthetic preservatives. This research assessed the ability of liquid smoke produced during pyrolysis of durian peel to preserve fish. Methods: Dry durian peel waste underwent batch reactor pyrolysis at 340°C and 380°C, resulting in production of liquid smoke (grade 3), charcoal, and tar. This liquid smoke was then distilled at 190°C to produce grade 1 liquid smoke, which was used to preserve mackerel. The preservation process was conducted by soaking the mackerel samples in liquid smoke at 0.5, 1, 2, and 3% concentration levels followed by observations every 6 hours. Tests to determine the total volatile base nitrogen (TVB-N) content, antibacterial quality of the liquid smoke and organoleptic quality of the fish were conducted in order to assess the preservation properties of the liquid smoke. Results: Tests on the antibacterial effects showed that the liquid smoke inhibited the growth of Escherichia coli and Staphylococcus aureus on fish even at low concentrations. At 54 hours, the TVB-N values remained below 30 mg nitrogen/g, indicating that the fish was still safe for human consumption. Results from the organoleptic tests showed that the concentration of liquid smoke influenced the preservation effects. Conclusions: At a concentration of 2–3%, the fish samples possessed acceptable flavor, taste, color and texture for up to 48 hours of soaking. However, the best conditions were obtained with a 3% concentration of liquid smoke (produced with 340°C pyrolysis), as the fish was still considered acceptable for up to 42 hours.

Effects of mineral matters on the interactions between lignite and corncob during temperature-programmed co-pyrolysis

A lignite and a corncob were employed to investigate the effects of the inherent minerals on the interactions between lignite and corncob during pyrolysis. Prior to pyrolysis experiments, the selected samples were demineralized by using HCl and HF solution. Pyrolysis experiments for the raw samples, demineralized samples and their various purposeful blends of lignite and corncob were conducted in a lab-scale fixed-bed reactor. The results showed that the inherent minerals can significantly affect the pyrolysis behavior of the individual feedstocks. Particularly, it was observed that the alkali and alkaline earth metal species (AAEMs) in corncob was capable of promoting the decomposition of tar macromolecules and cracking liquid tar to form gas and char, which thus led to an increased gas yields with distinct soot observed. In terms of the blends, it was observed that the blends of the demineralized corncob and the demineralized lignite produced an unexpected higher yield of liquid tar than other blends. This suggested that the AAEMs in corncob or lignite could play a catalytic role in the decomposition of tar macromolecules, and this catalytic ability in corncob became stronger than that in lignite. The experimental results also indicated that the catalytic ability of the AAEMs varied in the blends of lignite and corncob. For the blends of the raw samples of lignite and corncob, this catalytic ability of the AAEMs was weaker for decomposing tar macromolecules compared to that in the blends of raw corncob and demineralized lignite or demineralized corncob and raw lignite. The interaction between catalytically active K and Ca species from corncob and the aluminosilicate species in the coal mineral matter occur, leading to the formation of calcium silicate (Ca2SiO4), which resulted in the formation of inactive compounds. In addition, it was observed that the inherent minerals in the raw samples could promote the reactivity of char with oxygen, which could be particularly observed with the char made from the raw sample of corncob.

Properties of Coal from the Bayantig Deposit in Mongolia and Semicoking Products

The composition and thermal and technological properties of coal from the Bayantig deposit in Mongolia in a semicoking process were determined. It was established that the coal is vitrinite-type long-flame coal, and it gives an increased yield of liquid tar in the semicoking process. The composition and properties of semicoke and liquid tar as target semicoking products were characterized. Possible directions of the qualified use of semicoking products were determined based on composition characteristics.

Preliminary assessment of the utilization of durian peel liquid smoke as a natural preservative for mackerel

Background: Durian peel is a type of biomass waste that contains cellulose, hemicelluloses, and lignin. The pyrolysis of these compounds results in production of liquid smoke which can be used as a natural preservative to replace current synthetic preservatives. This research assessed the ability of liquid smoke produced during pyrolysis of durian peel to preserve fish. Methods: Dry durian peel waste underwent batch reactor pyrolysis at 340°C and 380°C, resulting in production of liquid smoke (grade 3), charcoal, and tar. This liquid smoke was then distilled at 190°C to produce grade 1 liquid smoke, which was used to preserve mackerel. The preservation process was conducted by soaking the mackerel samples in liquid smoke at 0.5, 1, 2, and 3% concentration levels followed by observations every 6 hours. Tests to determine the total volatile base (TVB) content, antibacterial quality of the liquid smoke and organoleptic quality of the fish were conducted in order to assess the preservation properties of the liquid smoke. Results: Tests on the antibacterial effects showed that the liquid smoke inhibited the growth of Escherichia coli and Staphylococcus aureus on fish even at low concentrations. At 54 hours, the TVB values remained below 30 mg nitrogen/g, indicating that the fish was still safe for human consumption. Results from the organoleptic tests showed that the concentration of liquid smoke influenced the preservation effects. Conclusions: At a concentration of 2-3%, the fish samples possessed acceptable flavor, taste, color and texture for up to 48 hours of soaking. However, the best conditions were obtained with a 3% concentration of liquid smoke (produced with 340°C pyrolysis), as the fish was still considered acceptable for up to 42 hours.

Property of upgraded solid and liquid products from Baganuur lignite by thermal reaction with solvent

The coal of Baganuur deposit have been investigated to determine its technical characteristics, elemental and petrographical maceral compositions. On the basis of proximate, ultimate, petrographic and FTIR analysis, the obtained results have confirmed that the Baganuur coal is a low rank lignite B2 mark. The liquid tar, produced through thermolysis of Baganuur coal, was investigated by FTIR, 13C and 1H NMR spectrometric analysis. The results of thermolysis of Baganuur coal in tetralin has a constant mass ratio between coal and tetralin (1:1.8) at 450°C, which shows that 40.0% of liquid product can be obtained after thermal decomposition of the coal organic mass.

Mild degradation of Powder River Basin sub-bituminous coal in environmentally benign supercritical CO2-ethanol system to produce valuable high-yield liquid tar

A novel and environmentally benign binary supercritical fluid system, comprised of supercritical CO2 and ethanol (SCCO2-ethanol), was employed to convert coal, a conventional energy resource, into high-value liquid tar which can be used as feedstock for the production of fuels/chemicals and carbon fibers. The SCCO2-ethanol system shows good performance for producing valuable liquid tar in high yield from Powder River Basin sub-bituminous coal. The results show that the highest yield of liquid tar reaches up to approximate 38 wt% (38 g/100 g raw coal) at 350 °C, and that SCCO2 can promote the liquid tar yield by 5.6 wt% compared to that using pure ethanol due to the synergistic effect between ethanol and SCCO2. The liquid tars are better candidates as clean fuels than the raw coal or even bituminous coal due to their higher heating values and almost free from ash. The liquid tars from degradation in SCCO2-ethanol (liquid tarSCCO2-ethanol) and in ethanol without SCCO2 (liquid tarethanol) at 350 °C were characterized with multiple analytical techniques. Fourier transform infrared analyses indicated that both liquid tars have similar distributions of functional groups. The proportion of volatile and small-molecular species in liquid tarSCCO2-ethanol is higher than liquid tarethanol according to thermogravimetric analysis. Further, gas chromatograph/mass spectrometry analyses show that phenols and aliphatic esters are the dominant volatile compounds in both liquid tars. The 1H and 13C nuclear magnetic resonance analyses reveal that both liquid tars have low aromaticity and liquid tarSCCO2-ethanol contains more aromatic carbons than liquid tarethanol, especially highly condensed aromatic carbons. Methylene and aliphatic and aromatic CH3 are the major aliphatic moieties in both liquid tars. The liquid tars can be separated into light oil and asphaltene fractions by extraction with n-heptane. In addition, the asphaltene fraction has potential to be used as the precursor for fabricating carbon nanofibers via electrospinning. Possible mechanisms for releasing volatile compounds and asphaltene from Powder River Basin sub-bituminous coal by SCCO2-ethanol degradation were also discussed.

Dry reforming of model biomass pyrolysis products to syngas by dielectric barrier discharge plasma

Biomass is frequently used to produce CO and H2 together with undesirable by-products containing CO2 and liquid tar by pyrolysis and gasification. This leads to decreased energy efficiency and increased maintenance costs. This study investigated the reforming of biogas and tar, respectively, using non-thermal plasma featuring dielectric barrier discharge (DBD). The gas surrogates studied were CH4 and CO2, and toluene was used as a substitute for tar. During reforming of biogas, CO or H2 was added to the CH4 and CO2 to investigate their effects on CH4 and CO2 conversion. Both the discharge power and gas components influenced the conversion of CH4 and CO2. The conversion efficiency of CH4 and CO2 and the selectivity of H2 and CO both increased with the discharge power while reforming the mixture of CH4 and CO2. The maximum conversion efficiency of CH4 and CO2 and selectivity of CO and H2 were obtained with a CH4:CO2 ratio of 1:2. During reforming of toluene, the conversion efficiency of toluene reached a maximum value of 90% and the production yields of H2, CO, and CO2 reached respective maximums of 0.79, 2.24, and 1.51 mol/mol-toluene at a discharge power of 90 W and temperature of 300 °C. Higher temperatures of 400–500 °C did not favour toluene destruction due to the thermal breakdown of the quartz dielectric and the rapid decrease in the discharging intensity. In addition, reaction mechanism for reforming of both biogas and toluene was proposed to improve our understanding of the reforming process in DBD plasma.

Scrap tyre pyrolysis: Modified chemical percolation devolatilization (M-CPD) to describe the influence of pyrolysis conditions on product yields

This paper attempts to develop a modified chemical percolation devolatilization (M-CPD) model that can include heat transfer, primary pyrolysis and the secondary cracking reactions of volatiles together to describe the pyrolysis of waste scrap tyre chip, as well as to examine the influence of operating conditions on the scrap tyre pyrolysis product yields. Such a study has yet to be conducted in the past, thereby leading to a large knowledge gap failing to understand the pyrolysis of the coarse feedstock appropriately. To validate the developed model, a number of operating parameters including reactor configurations, carrier gas compositions (argon and argon blended with CO2 and/or steam), scrap tyre chip size (0.5–15.0 mm), terminal pyrolysis temperature (400–800 °C) and heating rate (10 °C/min and 110 °C/min) were examined in a lab-scale fixed-bed pyrolyser, with a particular focus on the secondary cracking extents of the liquid tar. Through both experimental investigation and modelling approach, it was found that significant secondary cracking extent occurred upon the increase in the feedstock size, heating rate and residence time. Upon the fast pyrolysis, the average temperature gap between the centres of the coarse particle and reactor wall could reach a maximum of 115 °C for the tyre chips of 6–15 mm. Consequently, its primary volatiles underwent the secondary cracking reaction at an overall extent of 17% at a terminal temperature of 600 °C and a fast heating rate of 110 °C/min. Consequently, the yield of light gases including methane was increased remarkably. The flow rate of inert carrier gas was also influential in the secondary cracking, in which a maximum tar yield (54 wt%) was reached at a carrier gas flow rate of 1.5 L/min. This indicates the occurrence of secondary cracking has been largely minimised. At a pyrolysis temperature of 600 °C, the addition of CO2 in the carrier gas had an insignificant effect on the product yield distribution under the slow heating scheme. In contrast, the addition of steam resulted in a slight increase of carbon monoxide, presumably due to the occurrence of gasification reaction.

Analysis of ecotoxic influence of waste from the biomass gasification process

The purpose of this research was evaluation of the effect of soil contamination with waste coming from biomass gasification on chosen indicators of its biological activity, growth and development of spring barley, and change of physiological parameters of the plant. Chromatographic content and basic rheological parameters of the substances under research were also analyzed. Liquid wastes, tar, and mixture of tar and engine oil were introduced to the soil in the amount of 100 mg kg−1 DM soil. Based on the conducted research, it was ascertained that the changes in the number and activity of soil microorganisms were determined by the type of waste and its dose. Individual groups of microorganisms showed different sensitivity to the presence of pollution; however, the impact of tar and engine oil mixture was generally more disadvantageous. Presence of contaminants in the soil limited the growth of roots and aboveground parts of spring barley, especially when the dose was 10,000 mg kg−1 DM soil. The unfavorable impact of waste on photosynthesis efficiency on assimilation pigment synthesis and water content in the plant was recorded.

Pyrolysis of casein, characterization and properties of obtained solid and liquid products

Have been determined the technical characteristics and elemental composition of milk casein. Pyrolysis experiments of casein carried out at different heating temperatures and determined the yields of obtained solid (biochar), liquid (tar and pyrolysis water) and gas products. A temperature around 550ºC determined as an optimal heating temperature of pyrolysis and approximately 28.33% biochar, 37.38% tar, 13.23% pyrolysis water and 20.84% gas obtained after pyrolysis. First time a biochar with higher content of nitrogen was obtained by pyrolysis of casein and determined it is elemental composition and technical specifications. The porous structure of casein biochar was characterized by mercury porosimeter and SEM analysis confirmed that casein biochar has mostly meso and macro pores. The casein tar had the elemental composition: C-66.7%, H-8.3%, N-12.1%, O-12.9% and was completely soluble in 1-methyl-2-pyrroldinone. The tar consisted mostly of moderate molecular mass components with SEC elution times between 18-26 min and an estimated mass range up to 3000-5000 mass units as well as some larger size components, possibly 3-dimentional. The property and determined chemical composition of casein tar by GC/MS analysis were an evidence for using it as a curing agent for crosslinking reactions of epoxy resins. The necessary amount of tar for curing reaction of epoxy resin was determined experimentally as a 15-20% for the stoichiometric amount of reactive epoxy groups (15-20% epoxy group content) in epoxy resin and obtained cured epoxy resin with 95% degree of crosslinking reaction. Have been suggested several curing reaction schemes of epoxy resin with amines, nitriles and phenols of the casein tar