Pyrolysis Of Heavy Oil Research Articles

Low‐carbon pyrolysis of vacuum gas oil by non‐thermal plasma

AbstractThe constant growth in the share of renewable electricity and the need to reduce CO2 emissions create prospects for the development of non‐thermal plasma (NTP) pyrolysis of heavy oil. NTP pyrolysis requires only electricity and does not require heating of raw materials to high temperatures, which significantly reduces the carbon footprint during processing. This paper investigates the characteristics of NTP pyrolysis of vacuum gas oil under the action of electric microsecond discharges in the liquid phase, depending on the voltage of the current source 300–700 V to optimize energy consumption, conversion of raw materials, and increase the yield of commercial demand products.

Microwave catalytic pyrolysis of heavy oil: A lump kinetic study approach

Managing heavy oil (HO) has become a vital issue in terms of environmental considerations. Microwave pyrolysis of HO is one of the efficient methods of upgrading and recycling this complex material. In this work, microwave catalytic pyrolysis (MCP) of HO was explored by investigating the effect of heating time (2–10 minutes) and temperature (460–730ºC) on the product yield and quality. The most critical point of this study was utilizing a unique design of SiC foam@HZSM-5 as a microwave absorber and catalyst simultaneously. This special design could eliminate the main problem of previous studies: the unwanted temperature gradient inside the reactor, which was misleading the prediction of kinetic parameters by recording the wrong temperature. The yield of each product’s category from the MCP process was reconstructed through a biharmonic spline interpolation (BSI) algorithm to visualize the simultaneous effect of the heating time and temperature on the yield. The optimum temperature for the MCP process was about 600ºC and a heating time of 6 minutes, which yielded the most valuable hydrocarbons in liquid and gas products. The produced liquid oil and non-condensable gases were analyzed through GC-MS and the collected results were categorized based on the properties of the detected compounds. An eight-lump kinetic model was then proposed based on that categorization. The calculated pre-exponential factors (k0) were higher than the expected values, while the apparent activation energies (Ea) were considerably lower than the reported data in the literature, which was due to the non-thermal and thermal effects of microwave irradiation on the reaction mechanism. The validation of the proposed model indicated the capability of this model to predict reliable data under these conditions.

Preparation of Surface-Active Hyperbranched-Polymer-Encapsulated Nanometal as a Highly Efficient Cracking Catalyst for In Situ Combustion of Heavy Oil.

In situ combustion of heavy oil is currently the most suitable thermal method that meets energy consumption and carbon dioxide emission requirements for heavy oil recovery. The combustion catalyst needs to perform multiple roles for application; it should be capable of catalyzing heavy oil combustion at high temperatures, as well as be able to migrate in the geological formation for injection. In this work, a hyperbranched polymer composite nanometal fluid was used as the injection vector for a heavy oil in situ combustion catalyst, which enabled the catalyst to rapidly migrate to the surface of the oil phase in porous media and promoted heavy oil cracking deposition at high temperatures. Platinum (Pt) nanoparticles encapsulated with cetyl-hyperbranched poly(amide-amine) (CPAMAM), with high interfacial activity, were synthesized by a facile phase-transfer method; the resulting material is called Pt@CPAMAM. Pt@CPAMAM has good dispersion, and as an aqueous solution, it can reduce the interfacial tension between heavy oil and water. As a catalyst, it can improve the conversion rate during the pyrolysis of heavy oil in a nitrogen atmosphere. The catalyst structure designed in this study is closer to that exhibited in practical geological formation applications, making it a potential method for preparing catalysts for use in heavy oil in situ combustion to resolve the problem of catalyst migration in the geological formation.

Comparative pyrolysis kinetics of heavy oil and its SARA fractions using distributed activation energy model

The pyrolysis behaviors of Qingdao vacuum residue (QD-VR) and its SARA (saturates, aromatics, reins, and asphaltenes) fractions were evaluated by thermo-gravimetric with mass spectrometer (TG-MS). The pyrolysis kinetics were determined by Friedman, one-parallel and four-parallel distributed activation energy model (DAEM), respectively. The results indicated that the pyrolysis behavior of QD-VR was similar to that of aromatics. For saturates, the release of H2, CH4, CO, and CO2 occurred in 80–400 °C, while the temperature range for QD-VR and other fractions is 200–800 °C. The average activation energy (Ea) via Friedman method was 179.72 kJ/mol and increased with the conversion ratio. One-parallel Gaussian DAEM was more suitable to describe the pyrolysis process of the single SARA fractions, while four-parallel Gaussian DAEM was more suitable to describe the pyrolysis process of heavy oil. Furthermore, comparing the weighted Ea from one-parallel (227.64 kJ/mol) and four-parallel Gaussian DAEM (204.63 kJ/mol), the results suggested that during pyrolysis process of heavy oil, there was an interaction between the SARA fractions, which could reduce the Ea of heavy oil pyrolysis. Specifically, during heavy oil pyrolysis, resins and asphaltenes could increase the Ea of saturates and aromatics, while saturates and aromatics could decrease the Ea of resins and asphaltenes.

High quality products from microwave catalytic pyrolysis of heavy oil and polyethylene

Heavy hydrocarbon residue management has always been an environmental issue; thus, it is essential to find a method for upgrading heavy oils and plastic waste to high quality products as an alternative source of chemicals and fuels. In this study, the microwave catalytic pyrolysis (MCP) of heavy oil (HO) and LDPE (as plastic source) was proposed by employing a unique design of the catalyst, SiC foam@HZSM-5. This special catalyst design provided sufficient mass and heat transfer and enhanced the available catalyst surface area during the pyrolysis process. The effect of microwave power and the HO:LDPE ratio were investigated to optimize the product yield and quality. The results showed that the hazardous and unwanted elements of HO were eliminated by adding LDPE to the feedstock. More importantly, it was observed that the secondary and side reactions were accelerated due to a positive synergistic effect (ΔY), which occurred because of hydrogen donors from the LDPE degradation and the non-thermal effect of microwave heating. The HO:LDPE ratio of 1:1 with a microwave power of 800 W and 10 min heating time were the optimum conditions; the liquid yield was about 42 wt% with around 90% of aromatics (mono- and polycyclic) relative concentration. Furthermore, the proportion of BTX was about 82% of the liquid oil, while the concentration of oxygenated and nitrogenated compounds was less than 2%. Under the above conditions, the proportion of collected non-condensable gases was around 46 wt%, which comprised light olefins (C1-C6) at about 37%, and a considerable proportion of H2 as well. Additionally, adding more LDPE to the feedstock decreased solid residue by promoting the conversion of HO, which improved catalyst efficiency.

Research on the pyrolysis characteristics and kinetics of two typical inferior heavy oils

• Isoconversional methods and DAEM were used to calculate kinetic parameters. • Major weight loss of heavy oil pyrolysis occurred in active pyrolytic stage. • DAEM method had a high applicability to the pyrolysis of heavy oil. The present study deals with the pyrolysis characteristics of two typical inferior heavy oils slurry oil (SO) and deoiled asphalt (DOA) based on thermogravimetric data at multiple heating rates of 5, 10, 15 and 20 °C/min. Three isoconversional methods (Friedman, FWO and KAS) and distributed activation energy model (DAEM) method were used to evaluate the kinetics. The results showed that major mass loss of SO and DOA occurred in active pyrolytic stage, at which the mass loss rate reached up to 90.9 wt% (SO) and 55.5 wt% (DOA), respectively. The emissions of CH 4 , H 2 O, CO and CO 2 in the temperature range 400–600 °C contributed to the mass loss of DOA, whereas the mass loss of SO was ascribed to the cracking and condensation. The average activation energy ( E ) of SO and DOA were 101.48 and 219.32 kJ/mol for Friedman, 89.51 and 191.90 kJ/mol for FWO, 82.05 and 190.07 kJ/mol for KAS, respectively. DAEM method had a high applicability to the pyrolysis process of SO and DOA. The calculated peak proportions of four independent hypothetical components basically conformed to the fraction proportions of SO and DOA. The weighted E of DAEM method was higher than the average E of three isoconversional methods, explaining the four components of heavy oil was not single chemical reactions during pyrolysis, but interactive reaction.

Catalytic Effects of Fe3O4/GLC Nanocomposites for Pyrolysis of Heavy Oil

Catalytic Effects of Fe3O4/GLC Nanocomposites for Pyrolysis of Heavy Oil

Fundamental study of the integrated process of heavy oil pyrolysis and coke gasification. Part Ⅰ: Effect of CO and H2 in syngas atmosphere on heavy oil pyrolysis

An integrated process of heavy oil pyrolysis and coke gasification was proposed to realize the in-situ gasification of coke and provide syngas (CO/H2) atmosphere for heavy oil pyrolysis to obtain high-quality liquid products. To reveal the reaction mechanism of syngas (CO/H2) on heavy oil pyrolysis, the pyrolysis characterizations of three heavy oils including Dagang slurry oil (DG-SO), Qingdao vacuum residue (QD-VR) and Canadian oil-sands bitumen (CA-OB) were evaluated at different atmospheres (N2, CO, CO/H2, and H2). The results showed that compared with QD-VR and CA-OB, DG-SO with high content of aromatics but high Conradson carbon residue (CCR) value was not suitable for the integrated process of heavy oil pyrolysis and coke gasification. Compared with the N2 atmosphere, the pyrolysis oil yields of DG-SO, QD-VR, and CA-OB increased in turn under CO, CO/H2, and H2 atmospheres. On the contrary, their coke and gas yields decreased in turn. Furthermore, the contents of CH4, C2-C5, and CO2 in pyrolysis gases all decreased in turn, while the contents of their alkane, olefin, aromatic hydrocarbon, and oxygen /nitrogen/sulfur compounds in pyrolysis oil increased in turn. The change of oil and gas composition indicated that compared with N2, both CO and H2 could inhibit further decomposition of liquid products. The reactivity of coke showed that CO and H2 could reduce the degree of condensation of coke to increase its reactivity, but the effect of CO was not as good as that of H2.

Thermal Behavior of Heavy Oil Catalytic Pyrolysis and Aquathermolysis

There is still considerable controversy surrounding the mechanisms, thermodynamics, and kinetics of heavy oil aquathermolysis and pyrolysis processes. The present paper aims to widen our knowledge about the effect of iron tallates on pyrolysis and aquathermolysis of Cuban heavy oil. The obtained SARA (S: saturates, A: aromatics, R: resins, A: asphaltenes) analysis has shown a significant increase in light hydrocarbon content during aquathermolysis. Moreover, the elemental analysis has indicated an increase in C and H content by almost 4% and 6%, respectively, with a significant decrease in S and O content by up to 23% in the presence of iron tallates. These results have been further confirmed by infrared spectrometry. The obtained IR data indicated that asphaltene and resin compounds transform into light hydrocarbons after aquathermolysis. On another hand, the activation energy of heavy oil pyrolysis decreased in the presence of the utilized catalyst; meanwhile, the reaction rate increased, especially in the temperature range of 200–480 °C, which may validate a significant effect of the used catalyst in real conditions. Moreover, the obtained thermodynamic data showed a decrease in the enthalpy and entropy of activation of oil pyrolysis in the presence of iron tallates. Our results are encouraging in terms of energy consumption, optimization, and process control and should be validated by a larger sample size.

Effect of Fe nanoparticle-loaded sawdust carbon on catalytic pyrolysis of heavy oil

Effect of Fe nanoparticle-loaded sawdust carbon on catalytic pyrolysis of heavy oil

Fundamental Study of the Integrated Process of Heavy Oil Pyrolysis and Coke Gasification. Part I: Effect of Co and H2 in Syngas Atmosphere on Heavy Oil Pyrolysis

Fundamental Study of the Integrated Process of Heavy Oil Pyrolysis and Coke Gasification. Part I: Effect of Co and H2 in Syngas Atmosphere on Heavy Oil Pyrolysis

A Study of the Pyrolysis of Heavy Oil in Supercritical Cyclohexane: Experiments and Molecular Dynamics Simulations

A Study of the Pyrolysis of Heavy Oil in Supercritical Cyclohexane: Experiments and Molecular Dynamics Simulations

Fundamental Study of the Integrated Process of Heavy Oil Pyrolysis and Coke Gasification. Part Ii. Effect of Pyrolysis Temperature and Initial Syngas Pressure

Fundamental Study of the Integrated Process of Heavy Oil Pyrolysis and Coke Gasification. Part Ii. Effect of Pyrolysis Temperature and Initial Syngas Pressure

Experimental study of hydrogen generation from in-situ heavy oil gasification

Heavy oil in-situ gasification technology (ISG) produces hydrogen by injecting air and water into the formation and chemically react with the heavy oil, which can efficiently exploit oil and gas resources in the form of clean energy. The pyrolysis reaction of crude oil is particularly important for this technology regarding hydrogen generation. In this research, the mechanisms of hydrogen generation from heavy oil pyrolysis were investigated based on the thermogravimetric analyzer (TGA) and mass spectrometer (MS). The experimental results show that the weight loss of heavy oil under 25–900 °C can be divided into two stages. The first stage is mainly the evaporation of light fractions, which corresponds to the physical stage. The second stage contains pyrolysis and coke dehydrogenation reactions, which is considered as the chemical stage. Also, the study indicates that the hydrogen generation occurs in both pyrolysis and coke dehydrogenation reactions, and 80% of hydrogen is generated from the coke dehydrogenation reaction with corresponding reaction temperature range of 528–820 °C. Furthermore, the kinetic parameters of heavy oil pyrolysis were obtained based on the distributed activation energy model (DAEM), where the apparent activation energy of the coke dehydrogenation reaction is greater than 350 kJ/mol, and the reaction frequency factor (k0) is greater than 2.83 × 1023 s−1. The reaction kinetic parameters obtained in this paper and the established law of hydrogen generation by heavy oil under thermal effect lay the foundation for further research on ISG technology.

Pyrolysis of heavy oil in supercritical multi-thermal fluid: An effective recovery agent for heavy oils

As a novel thermal agent, supercritical multi-thermal fluid (SCMTF) has great potential to be used for heavy oil reservoirs. However, its viability and enhanced oil recovery (EOR) mechanisms have not been investigated. Therefore, a series of tests were conducted in a newly designed autoclave to compare crude oil pyrolysis in steam, supercritical water (SCW), SCW + supercritical nitrogen (scN2), SCW + supercritical carbon dioxide (scCO2) and SCMTF, and the viability of SCMTF was evaluated. Then, the possible mechanisms of pyrolysis in SCMTF were proposed. Finally, the effects of temperature, pressure, and the amount of SCMTF on pyrolysis in SCMTF were investigated. The results show that the SCMTF treatment of raw crude oil at 653 K and 23 MPa resulted in molecular weight, density and C15+ content reduction rates of 44.67%, 6.45% and 12.06%, respectively, and gave a gas yield of 7.91 wt % and an increase in the light oil fraction of 10.17 wt %. SCMTF is more effective than steam, SCW and SCW + scN2 for upgrading heavy oil. In detail, SCW dominates the pyrolysis processes; scCO2 accelerates dealkylation, and increases oil mobility by dissolution and light hydrocarbons extraction; and scN2 can maintain reservoir pressure and form a gas-cap, which reduces heat loss. Increases in scCO2 fraction, temperature, pressure and the amount of SCMTF can enhance the heavy oil upgrading. However, pyrolysis at a high temperature is adverse to light oil production (the oil product yield was merely 67.10% at 683 K) due to undesirably high gas and coke yields of 13.32% and 19.58%, respectively.

Demetallization of Heavy Oils of High Metal Content through Pyrolysis under Supercritical Water Environment

Through pyrolysis under a supercritical water (SCW) environment, the demetallization of Tsingtao vacuum residuum (VR) and Tahe atmospheric residuum (AR) with a total vanadium and nickel content above 300 ppm was studied. By introducing SCW, pyrolysis of heavy oil can be carried out in an emulsion structure in which heavy fractions rich in metals are concentrated in oil droplets. A metal removal rate higher than 90 % could be obtained in 2 h, which is faster than the pyrolysis under the nitrogen environment. Although two heavy oils have similar apparent properties, Tsingtao VR is characterized by the metal enrichment in the heaviest asphaltenes and the higher condensation activity of asphaltenes. Because of the preferential condensation of heavy fractions rich in metals, the liquid product yield of Tsingtao VR could be 15 wt% higher than that of Tahe AR at the metal removal rate of 70 to 90%.

A Mechanistic Study of Layered-Double Hydroxide (LDH)-Derived Nickel-Enriched Mixed Oxide (Ni-MMO) in Ultradispersed Catalytic Pyrolysis of Heavy Oil and Related Petroleum Coke Formation.

Heavy oil contains a significantly lower H/C ratio and higher quantity of organic heteroatoms and organo-metallic complexes than conventional light oil. Consequently, novel catalytic materials are needed to aid in heavy oil upgrading to remove the deleterious components and support the higher demand for low sulfur and higher value fuels. Heavy oil upgrading was studied using an inexpensive nickel-aluminum Layered Double Hydroxide (LDH)-derived Ni-enriched Mixed Metal Oxides (Ni-MMO) dispersed catalyst in a Baskerville autoclave. The conditions were set at 425 °C, initial pressure of 20 bar, 0.02 Catalyst-To-Oil (CTO) ratio, and a residence time of 30 min to mimick previously optimized conditions for in situ upgrading processes. The extent of the upgrading following catalytic pyrolysis was evaluated in terms of a solid, liquid, and gaseous phase mass balance, liquid viscosity reduction, desulphurization, and True Boiling Point (TBP) distribution. A typical in situ activated CoMo-alumina commercial hydroprocessing catalyst was used as a reference. It was found that the produced oil from dispersed ultrafine Ni-MMO exhibited superior light oil characteristics. The viscosity decreased from 811 to 0.2 mPa·s while the light naptha fraction increased from 12.6% of the feed to 39.6%, with respect to the feed. Using a thorough suite of analytical techniques on the petroleum coke product, including Thermogravimetric Analysis (TGA) and Scanning Electron Microscopy (SEM), a reaction mechanism has been hypothesized for the upgrading by dispersed Ni-MMO under both N2 and H2 atmospheres. Under a N2 atmosphere, the Ni-MMO, generated by the in situ thermal decomposition of the LDH, demonstrate a preferential asphaltene and poly aromatic adsorption mechanism, generating a poly aromatic mixed oxide-coke precursor. While using Ni-enriched mixed oxides under a reducing H2 atmosphere, hydrogenation reactions become more significant.

A six-lumped kinetic model of pyrolysis of heavy oil in supercritical methanol

The product distribution of pyrolysis of heavy oil in the supercritical methanol (SC-MeOH) was studied. It could be found that the pyrolysis reaction rate enhanced with the increase of temperature. Compared with reaction in N2, the coking formation was promoted in SC-MeOH. It was attributed to “cage effect” caused by methanol. The aromatics and resins which can dissolve asphaltenes were isolated by cages. Therefore, more coke was formed by condensation of asphaltenes. A lumped reaction kinetic model modified by equilibrium mass fraction of aromatics and resins was established, which could describe and predict the products distribution in SC-MeOH.

Fast Pyrolysis of Qinhuangdao Vacuum Residue at High Temperature by Py-GC/MS

The liquid-phase cracking is inevitable in the pyrolysis of heavy oil because of the high boiling point of residues. To enhance the gas-phase cracking of residues, the raction temperature and heating rate processing scheme was performed in a Py-GC/MS apparatus. The results showed that the yields of gasoline and diesel fractions reached the maximum at 750°C and 2000°C/s. Thus, to reduce coking amount and raise liquid yield in industrial thermal processing of vacuum residue, the reaction temperature and heating rate should be enhanced.

The enhanced thermolysis of heavy oil contaminated soil using CO2 for soil remediation and energy recovery

The enhanced thermolysis of heavy oil contaminated soil using CO2 as reaction medium for the simultaneous soil remediation and energy recovery was investigated. To avoid any complexities arising from the heterogeneous matrix of soil, heavy oil contaminated soil was artificially mimicked by means of homogenizing sand and bunker C (the mass ratio of sand to oil was adjusted as 10). The TGA (thermo-gravimetric analysis)/DTG (differential thermogram)/DSC (differential scanning calorimeter) tests of bunker C oil in N2 and CO2 revealed that all physical aspects ruling mass loss, thermal degradation rate, and energy input were not affected by reaction medium (CO2). However, all pyrogenic products were noticeably modified in the thermal degradation of bunker C oil contaminated soil in the CO2 environment under the ambient pressure. In detail, shifting carbon distribution from the liquid products to the gaseous products (syngas) in the presence of CO2 was observed. Also, the thermal degradation of bunker C oil contaminated soil led to carbon fixation onto soil, but the surface morphologies of charring material was modified in the presence of CO2. Considering that no leaching of any chemical species from charring material, pyrolysis of heavy oil could be a viable option to remediate and stabilize heavy oil contaminated soil while recovering energy. Employing CO2 as reaction medium in the thermolysis of heavy oil contaminated soil could provide a strategic means for the soil remediation contaminated with organic pollutants by means of modifying all pyrogenic products without an additional energy input.