Liquid Pyrolysis Products Research Articles

Characteristics of Distillation Residues from Liquid Pyrolysis Products

Heavy ends obtained from thermomechanical distillation of water-tar emulsions of liquid pyrolysis products from a broad fraction of light hydrocarbons and the ethane fraction were studied. Their physicochemical parameters were determined. Various processing schemes for heavy ends were proposed. It was found that the properties of used diesel fuel (UDF) were closest to those of the products. The high densities of the products limited the use of heavy ends as UDF. This problem was solved by proposing a shift of the UDF and vat residue ratio to 4:1 to produce commercial UDF blends.

Producing of qualified oil and carbon black from waste tyres and pet bottles in a newly designed pyrolysis reactor

Waste tyre and waste polyethylene terephthalate (PET) bottles are major environmental problems. In this study, by using newly designed simple and efficient pyrolysis reactor, a five-stage decomposition (200, 300, 400, 500 and 600 °C) and pre-condensation with cooler motor (− 20, − 10, 0, + 10 and + 20 °C) followed by a final condensation were applied to waste tyre and waste PET bottles. In the pyrolysis process, liquid (pyrolytic oil) and solid (carbon black) products were obtained from only waste tyres. Waste PET gasified in the decomposition steps, but pyrolytic oil could not be obtained because it tended to freeze during condensations. Intermediate temperature and cooling steps were tried by making an optimum design for the amount/efficiency of the pyrolytic oil obtained from waste tyre, and the combination giving the best result (about 50–60% for yield and 43.1 MJ kg−1 for the highest calorific value) was determined to be 500 °C and + 20 °C as decomposition and condensation temperatures, respectively. Compared to the literature, it was produced a highly productive pyrolytic oil at lower temperatures. The physical and chemical properties of this oil were in accordance with national and international standards in terms of the fundamental parameters. The net calorific value of the carbon black produced was in the range of 6337–7308 kcal kg−1 (26.5–30.6 MJ kg−1).

Properties and Applications of Distillate Fractions from Highly Stable Dispersions of Liquid Pyrolysis Products

Modern reprocessing and recycling methods for liquid pyrolysis products from hydrocarbon feedstock are analyzed. Hydrocarbon fractions produced during distillation of highly stable dispersions of liquid pyrolysis products from a broad fraction of light hydrocarbons and an ethane fraction are studied. The main physicochemical parameters and fractional and component compositions of the obtained distillates are determined. The products are analyzed for compliance with requirements for grade E-1 and E-18 liquid pyrolysis products. The obtained hydrocarbon distillates were found to meet requirements of TU 2451-179-00203335-2008 for grade E-1 liquid pyrolysis products.

Thermomechanical Dehydration of Highly-Stable Dispersions of Liquid Pyrolysis Products

Highly organized and highly stable water—hydrocarbon dispersions of liquid pyrolysis products and an ethane fraction were studied. Water evaporation was used as a dehydration method. Mixtures containing a water cut (20-75 mass%) were studied. Feedstock was separated by a thermomechanical method into bottom-product and distillate fractions. The dehydration efficiency was assessed based on the water cut in the bottom products. The water content in all studied mixtures was reduced to trace levels in the bottom products. Increasing the water cut in the emulsions was shown to increase the ratio of recovered hydrocarbon distillate to bottom products whereas diluting the starting emulsion with light pyrolysis resin had the opposite effect on the yield of dehydration products depending on the starting pyrolysis feedstock.

Synthesis of Hydrocarbon Resins by Thermal Polymerization of Unsaturated Compounds of Pyrolysis Fractions

Hydrocarbon resins were synthesized by thermal polymerization of the olefinic compounds of liquid pyrolysis products (the C9+ fraction, heavy tar). The hydrocarbon resins were characterized by 1H NMR spectroscopy, MALDI spectroscopy, and gel permeation chromatography. The effect of temperature, reaction time, feed composition, and solvent content on the yield, molecular weight, color, and molecular structure of the hydrocarbon resins was investigated. It was shown that addition of the C9+ fraction to heavy tar increases the polymer yield while reducing the content of aromatic fragments in its structure.

Thermo-catalytic degradation of different plastics to drop in liquid fuel using calcium bentonite catalyst

Thermal and catalytic pyrolysis of individual plastics such as polypropylene (PP), low-density polyethylene (LDPE), high-density polyethylene (HDPE), and mixture of all three plastics (PP + LDPE + HDPE) were carried out in the presence of calcium bentonite as catalyst in a batch reactor to obtain suitable liquid fuel. The dependencies of process temperature, effect of catalyst, feed composition on yield of the fuel fraction were determined. The major product of both thermal and catalytic pyrolysis was condensable fraction in the temperature range 400–550 °C. The reaction rate, quality and quantity of the major products changed with change of temperature and catalyst concentration. The highest yield of pyrolysis liquid product was 88.5 wt% from PP, 82 wt% from LDPE, 82.5% from HDPE and 81 wt% from mixed plastics at 500 °C with 1:3 catalyst to plastic ratio. The oil obtained in this process was analyzed using FTIR and GC–MS for its composition. Fuel properties of the oil are evaluated to understand its uses as a fuel or chemical feedstock.

Slow pyrolysis of walnut shells in nitrogen and carbon dioxide

Previous studies have shown that increased carbon dioxide concentration upon heat up affects the products of coal pyrolysis and in particular that chars prepared under carbon dioxide rich atmospheres are less reactive than chars prepared in nitrogen, and consistently tars are more aromatic. In the present work, this issue is investigated with reference to a biomass, namely walnut shells (WS), where the lignin component prevails over cellulose and hemicellulose.Preliminary experiments of thermal degradation have been carried out using a thermogravimetric (TG) apparatus, under constant heating rate conditions, in flows of either nitrogen or carbon dioxide. Derivative thermogravimetric (DTG) curves reveal the existence of multiple peaks, which are typically associated with the degradation of different ligno-cellulosic components. A multiple parallel reaction scheme has therefore been used to fit the experimental data and kinetic parameters have been obtained.Walnut shells were also pyrolyzed in a fixed bed reactor at 600 °C in either nitrogen or carbon dioxide so as to collect pyrolysis products in amounts sufficient for further analysis. Char and tar samples have been characterized using different techniques (e.g. GC–MS, elemental analysis, TGA, SEM) revealing limited differences. Combustion rates of the chars have been measured by means of non-isothermal thermogravimetric experiments in air and again small differences have been observed between the samples prepared under carbon dioxide and nitrogen.It has been concluded that under the low heating rate conditions typical of the thermogravimetric apparatus and fixed bed reactor used in the work, the effects of carbon dioxide on liquid and solid products of biomass pyrolysis exist but are less important than for coal.The work is complementary to another paper, which addresses the effect of carbon dioxide on biomass pyrolysis under high temperature and fast heating rate conditions in a drop tube reactor.

Resole-Type Phenol–Formaldehyde Resin with Neutralized Liquid Products of Fast Pyrolysis of Birch Wood

A method of preparation of a phenol–formaldehyde resin by replacing phenol with liquid products of the fast pyrolysis of wood is described. Strength tests reveal that substituting a pyrolysis liquid for 60% of phenol in the phenol–formaldehyde resin allows strength to be increased by 6% relative to the control sample.

Modification of bitumen binder by the liquid products of wood fast pyrolysis

The physical and chemical properties of fast pyrolysis products and the composite binder were studied. Samples of the composite binder with additions of pyrolysis oil (PO) and pyrolytic lignin (PL) were obtained, and their properties were investigated. The results from binder analysis show that PO can be used as a component for the road binder in content up to 1%; and PL in content up to 10%. A significant reproducible volume increase was detected at a temperature range of 100–140°C in the composite binder with PL compared to initial binder. The volume increase can decrease binder consumption by 4 times. Samples of asphalt concrete made with the composite binder were obtained, their properties were studied. The results from asphalt concrete analysis show that PL can be used in content up to 5%.

The roles of the low molecular weight compounds in the low-temperature pyrolysis of low-rank coal

To investigate the roles of the low molecular weight compounds (LMWCs) in the low-temperature pyrolysis of low-rank coal, Hongliulin coal (HL) was firstly thermal dissolved in n-hexane (HEX) at 260–340 °C, and the pyrolysis characteristics and product distributions of HL and its residues of thermal dissolution (RTDs) were compared. Results show that the LMWCs have a significant effect on the low-temperature pyrolysis characteristics of HL. The pyrolysis liquid (PL260-340) and gaseous product yields of RTDs, which decrease with rising TD temperature (TDT), are dramatically lower than those of HL. The total amounts of HEX soluble portion (SP) and PL at the TDT of 260 and 280 °C are essentially equal to PLHL, implying that almost all LMWCs, which with relatively low boiling point, can be directly evaporated and transferred into tar during the pyrolysis of HL. The GC/MS analysis indicates that the LMWCs contain some hydrogen-donor components (such as tetralin and indane) which can act as hydrogen donor for the stabilization of radical fragments during HL pyrolysis process.

Slow pyrolysis of organic fraction of municipal solid waste (OFMSW): Characterisation of products and screening of the aqueous liquid product for anaerobic digestion

A comprehensive study of the energy yield from slow pyrolysis of the organic fraction of municipal solid waste (OFMSW) and energy recovery from the aqueous liquid product by anaerobic digestion has been carried out. In this paper, the results of the liquid pyrolysis product characterisation are presented, with toxicity and methane potential assessments of the aqueous liquid product. The OFMSW feedstock was obtained from a UK waste treatment plant. Shredded samples dried to different moisture contents (12.7–45.8%) were processed in a 300 g per hour auger screw pyrolysis reactor at temperatures from 450 to 850 °C. Sixteen pyrolysis runs were performed, with process mass balance closures above 90% obtained (wet feed basis). Pyrolysis liquids showed clear phase separation under gravity. With increasing processing temperature, the liquid yield (both organic and aqueous fraction) reduced but the gas yield increased. An investigation into the product energy distribution indicated that processing temperature had a strong effect on the product energy distribution, while the effect of feedstock moisture was relatively small. Batch anaerobic testing of the aqueous fraction showed that toxicity increased with pyrolysis processing temperature and decreased with feedstock moisture content. Statistical analysis confirmed that the pyrolysis processing temperature was the dominant factor affecting the toxicity of the aqueous product. Careful acclimatisation of the microbial consortium to the applied substrate and loading is likely to be necessary for improved digestion of the aqueous fraction.

CHARACTERISATION OF MONGOLIAN EAST KHOOT COAL AND ITS PYROLYSIS PRODUCTS

Pyrolysis of East Khoot coal was carried out at different heating temperatures and yields of solid, liquid and gaseous products were determined. It was discovered that the optimal heating temperature is 500-550°C. Raw coal from the East Khoot deposit and pyrolysed coal samples were analysed for ash content and composition. The results of proximate, ultimate and petrographic analysis confirm that the East Khoot coal is a low-grade (B2) brown coal. The porosity of raw coal, char of pyrolysed coal and activated carbon of pyrolysed char was determined by means of scanning electron microscopes. The liquid tar product of pyrolysed East Khoot coal was investigated using Fourier transform infrared spectroscopy and its liquid tar pyrolysis product by means of GC/MS chromatography.

Synthesis of carbon foam with cellular structure by pyrolysis of light alkanes

A two-stage method for the synthesis of carbon foam with cellular structure is proposed.In the first stage, liquid products of pyrolysis of the propane-butane mixture are obtained in the presence of an inert gas, in the second stage these products are foamed at a temperature of 850 °C with the formation of carbon of cellular morphology.It has been found that liquid products predominantly consist of polycyclic aromatic compounds of different composition. The paper presents data on the structure and some physico-chemical characteristics of the material obtained.

The Effect of Catalyst Ratio on the Pyrolysis Yields for Waste Tyre

This paper focus on the thermal pyrolysis of used tyre with different catalysts at a temperature 550°C and at a heating rate of 15°C/min. The effect of process parameters on liquid yield, char formation and volatiles were also studied. In the present work, thermal pyrolysis of waste tyre samples with two selected catalysts, namely Jordan zeolite (zeolite Jo) and activated alumina was carried out in a fixed-bed reactor. The catalyst was mixed with feedstock in different percentages (10%, 15%, 25% and 35% w/w). The effects of catalysts and their ratio on the pyrolysis product oil were investigated and the results were compared with the results of experiments performed without catalyst under the same conditions (temperature 550°C at a heating rate of 150C/min). The maximum liquid yield obtained from pyrolysis of waste tyre via catalyst were found as 49.32% and 51.54% on using activated alumina and zeolite Jo as catalysts, respectively, while these values were 42.48%, without catalyst. The mass loss of tyre was examined using the thermo gravimetric analysis profiles (TGA) at heating rate of 15°C/min in air atmosphere from room temperature up to 600°C. The tyre pyrolysis liquid product has been characterized including fuel properties, proximate analysis, and ultimate analysis and FTIR. Fuel properties show that it can be used as liquid fuels.

A comparison of CO2, N2, and Ar to maximize plant nutrient retention in biochar

Nutrient-rich biochar improves soil significantly; however, the nutrients nitrogen (N), phosphorous (P), and potassium (K) can be easily lost during the pyrolysis of straw feedstock. To resolve this problem, the mechanism for retaining the biochar nutrient elements in the solid, liquid, and gas products of pyrolysis under different atmospheric conditions and at different temperatures was studied systematically so that the best method for the preparation of the biochar could be determined. The observations are as follows: (1) the CO2 atmosphere was more favourable than the N2 atmosphere for biochar preparation; (2) at 400 °C, the carbon in the biochar was mainly in the form of conjugated aromatic carbon; (3) when the temperature increased from 300 to 600 °C, the nitrogen content in the biochar decreased from 88.42 to 39.02%; (4) most of the phosphorus and potassium were mainly retained in the biochar; (5) the lower pyrolysis temperature (400 °C) under a CO2 atmosphere is the best biochar preparation conditions for promoting lettuce growth.

Joint Thermal Treatment of Heavy Oil and Liquid Products of Fast Wood Pyrolysis for Producing Fuels and Chemicals

Joint thermal treatment of heavy oil and liquid products of fast wood pyrolysis is investigated. Thermal analysis shows that the coke yield does not increase if the liquid products are added up to 20 mass%. The liquid wood-pyrolysis products decompose much earlier than heavy oil. However, the decomposition of the blends is essentially the same as pure-oil decomposition.

Effect of Ionic Liquid 1-Butyl-3-Methyl-Imidazolium Dihydrogen Phosphate Pretreatment on Pyrolysis of Lignin

In order to improve the yield of liquid fraction and phenolics content during lignin pyrolysis, an effective method of lignin pyrolysis through the pretreatment of lignin by an acidic ionic liquid 1-butyl-3- methyl-imidazolium dihydrogen phosphate ([Bmim]H2PO4) at low temperature is investigated in this study. It is found that [Bmim]H2PO4 pretreatment increases the total yield of liquid products of lignin pyrolysis compared to that of original lignin. The [Bmim]H2PO4 pretreatment temperature significantly impacts the behaviors of the lignin pyrolysis. In the temperature range of 50 to 150°C, the yield of the overall liquid product obtained by pyrolysis of the sample pretreated at 50°C is the highest. After pretreatment, the [Bmim]H2PO4 can be efficiently recovered, but the structure and stability of the [Bmim]H2PO4 have been changed. The FTIR analysis shows that the ionic liquid [Bmim]H2PO4 pretreatment can break hydrogen bonds, ether linkages and ester bonds in lignin.

Pyrolysis of Palm Oil in a Continuous Flow Microchannel Reactor

Palm oil is considered as a potential feedstock for biofuel production in Thailand due to its property and availability. In recent years, there has been an increased attention on upgrading of palm oil to biofuels using various technologies. One of the most promising technologies is pyrolysis, in which palm oil is heated at the temperature in the range of 400 to 500 °C under oxygen-free atmosphere. In the present study, the uncoated catalyst and coated catalyst pyrolysis processes of palm oil for biofuel production in a continuous flow microchannel reactor were investigated with various catalyst types (MgO, Al2O3) at 400-500 °C, 2 ml/hr palm oil flow rate, and 0.1 g of catalysts. Liquid product yield, solid product yield and gaseous product yield were determined. The obtained results revealed that the high triglyceride conversion could be achieved at a short reaction time in microchannel reactor, which attributed to the enhancement of both heat and mass transfer. The pyrolysis liquid products composed of hydrocarbons, free fatty acids, and other oxygenated compounds which are the results of triglyceride cracking. Furthermore, product selectivity of palm oil pyrolysis depended on temperature and catalyst type.

High-Performance thermal polymerization inhibitors based on 4-tert-Butylcatechol and its compositions for petrochemical plants

tert-Butylcatechol (TBC) has been tested under laboratory conditions as an inhibitor of undesired polymerization during the processing of liquid pyrolysis products and has shown high efficiency. Pilot- and industrial-scale tests and evaluation of TBC as an inhibitor in the thermal treatment of styrene have been carried out. It has been shown that this inhibitor operates only in a composition with other co-inhibitors. An inhibitory composition of TBC and copper diethyldithiocarbamate is proposed, which has shown high performance in the thermal treatment of both pyrolysis condensates and styrene. Other TBC formulations with monohydric sterically hindered phenols have been considered.

THE PYROCARBON FORMATION MECHANISM DURING THE HYDROCARBON PYROLYSIS PROCESS

Experimental results confirming the mechanism of pyrocarbon formation through the steps of high-molecular pyrolysis products forming in the gas phase are presented. Adsorption of high-molecular pyrolysis products on the active centers of the substrate localized at the boundaries of the contacts of its crystallites and their subsequent carbonization is confirmed. The decreasing in the length of the substrate crystallites contact boundaries leads to the increase in the content of high-molecular compounds in the gas and to the decrease in the hydrogen concentration is shown. The relation between the composition of the exhaust gas and the surface of the sealing material creates the prerequisites for controlling the pyro-consolidation process according the composition of the off-gas. The composition of high-molecular liquid pyrolysis products was identified. The difference in the composition of high-molecular pyrolysis products of the propane-butane fraction and the electric cracking gas was established. The influence of raw materials and pyrolysis conditions on the group composition of high-molecular pyrolysis products formed is shown.