Crude Oil Pyrolysis Research Articles

Thermocatalytic in situ combustion: Influence of nanoparticles on crude oil pyrolysis and oxidation

Over the last decade great interests have been devoted to the application of nanoparticles (NPs) in improving the performance of thermal recovery processes. In this study utilizing NP, a novel method to improve the performance of in situ combustion process is presented. Thermal analysis and kinetic studies have been performed to study how thermocatalytic conversion of crude oil is influenced by NP.From the results of this study a dual catalytic/surface area effect of NP on crude oil pyrolysis and oxidation reactions can be pointed out. NP increase the amount of the fuel that is formed during low temperature oxidation reactions and also pyrolysis of crude oil compounds. NP also catalyze the high temperature combustion reactions by lowering the activation energies. Therefore by increasing the amount of fuel deposited, NP improves the stability and propagation of the combustion front of medium and also lighter crude oils.

New technologies in the production of motor fuels from renewable materials

This work presents resources of the Autonomous Province of Vojvodina available for bioethanol and motor fuels (gasoline and diesel fuel) from sustainable resources: corn-stalks, straw, sweet sorghum, pork fat. The physicochemical basis for novel processes for motor fuel production is coupling microwave pyrolysis of oil shale and catalytic cracking of purified pyrolysis oil, hydrothermal liquefaction of algae and swine manure. The effects of the degree of purification of crude pyrolysis oil and oil shale on the degree of their conversion to gasoline and diesel fuel, as well as the product distribution are investigated. The effects of the duration and temperature of hydrothermal liquefaction of microalga, Botryoccocus braunii, and swine manure on their degrees of conversion into bio-oil and its thermal properties are investigated. The development of novel strategy of biofuel in the Autonomous Province of Vojvodina is presented.

Fractions composition study of the pyrolysis oil obtained from sewage sludge treatment plant

In this work the parameters of Low Temperature Conversion – LTC were applied in a centrifuged sludge from a sewage treatment plant located in Rio de Janeiro, Brazil. Before the conversion, the sludge was dried and analyzed by TGA to observe its behavior with increasing temperature. The chemical composition of the crude pyrolysis oil was analyzed by FTIR, 1H NMR and GC–MS. The results showed that the oil is a mixture of hydrocarbons, oxygenated and nitrogenated compounds. Using a catalytic treatment it was possible to fractionate the oil where the predominant constituents were hydrocarbons showing that the cracking was effective. An important result was the difference between the calorific value of dry sludge (10MJkg−1), the pyrolysis oil (36MJkg−1) and one of the fractions separated by catalytic cracking (40MJkg−1) when compared with commercial diesel (45MJkg−1).

Characteristics and Kinetics of Gaseous Hydrocarbon Generation from Pyrolysis of Crude Oil under High Pressure and High Temperature

The pyrolysis of three oil samples from Tarim Basin was carried out under 390°C and high pressures formed by injecting N2in the closed system and the influences of temperature, time and the oil compositions on the pyrolysis reaction of oil to gas were discussed. The gas generation ratio increased and average activation energy decreased with the content of polar compositions in oil, and the gas generation ratio changed intensively with reaction time for high content of polar compositions under the experimental conditions. The effect of pressure on pyrolysis of oil was tightly related to oil composition. High pressure was beneficial to the pryolysis of oil with more polar compositions. The calculated value of the gas generation ratio fitted well with experiment value as the parallel first order reaction model containing 11 reactions with different activation energies and different preexponential factors was used for simulating the pyrolysis reaction of oil to gas by minimizing objective function with MATLAB optimization module.

Feasibility study for thermal treatment of solid tire wastes in Bangladesh by using pyrolysis technology

In this study on the basis of lab data and available resources in Bangladesh, feasibility study has been carried out for pyrolysis process converting solid tire wastes into pyrolysis oils, solid char and gases. The process considered for detailed analysis was fixed-bed fire-tube heating pyrolysis reactor system. The comparative techno-economic assessment was carried out in US$ for three different sizes plants: medium commercial scale (144 tons/day), small commercial scale (36 tons/day), pilot scale (3.6 tons/day). The assessment showed that medium commercial scale plant was economically feasible, with the lowest unit production cost than small commercial and pilot scale plants for the production of crude pyrolysis oil that could be used as boiler fuel oil and for the production of upgraded liquid-products.

Genetic origins of marine gases in the Tazhong area of the Tarim basin, NW China: Implications from the pyrolysis of marine kerogens and crude oil

Abstract Although abundant natural gases have been discovered in Carboniferous and Ordovician reservoirs in the Tazhong area, central Tarim basin, their genetic origins is still an open question because of significant variations in chemical and carbon isotopic compositions. In the present study, three samples representing the possible gas sources were pyrolyzed using sealed gold tubes to investigate their gas potentials, and chemical and carbon isotopic signatures. The samples were a crude oil, a low maturity kerogen and a high maturity kerogen. The results show that the chemical and isotopic compositions of gaseous pyrolysates from the three samples are quite different. Generally, the gases from oil cracking are compositionally wetter and isotopically lighter than those from kerogen cracking at similar thermal levels. The large quantities of methane experimentally observed in oil cracking gases are mainly associated with the re-cracking of wet gases at very high maturity levels. Methane in gases derived from kerogen, especially high maturity kerogen, in contrary, is mainly generated by the demethylation reaction. The diagrams of δ13C1 vs. δ13C2–δ13C3 and C2/C3 vs. δ13C2–δ13C3, along with natural gas plots, have proven to be a very effective tool in the genetic interpretation of natural gases from kerogen and oil cracking in the Tarim basin. Their combined application shows that two types of gas source can be identified in the Tazhong area. The first type is oil cracking gas, mainly discovered in Carboniferous reservoirs of the central fault horst area, but also partly in Ordovician reservoirs, such as in the wells TZ45, TZ44b and TZ 16. The other is kerogen cracking gas occurring largely in Ordovician reservoirs, especially in the North Slope area. The two types of gases, however, are mixed in many reservoirs as their generation is overlapped in time and/or space. This mixing process is especially obvious for methane.

Hydrogen production from crude pyrolysis oil by a sequential catalytic process

A sequential process aiming at hydrogen production was studied over two Ni-based catalysts, using crude beech-wood oil as the feed. The process alternates cracking/reforming steps, during which a H2+CO rich stream is produced and carbon is stored on the catalyst, with regeneration steps where the carbon is combusted under oxygen. The two catalysts exhibited good performances for H2 production from bio-oil, the gaseous products stream consisting in 45–50% H2. The regeneration step was found fast and efficient, the coke being readily combusted and the catalyst activity fully recovered. A positive heat balance between the endothermic cracking/reforming reactions and the exothermic coke combustion suggests that an autothermal process could be designed. Comparison of the thermal decomposition of bio-oil (empty reactor) with the catalytic cracking revealed that they are first decomposed into primary light gases (CO, CO2, CH4, C2+) and soots. These compounds are further reformed onto the catalyst by the steam contained in bio-oil, and equilibrated via the WGS reaction. The key roles of the catalyst are therefore (i) to improve the overall bio-oil gasification into syngas, (ii) to promote steam reactions and increase hydrogen production by steam reforming and WGS and (iii) to control and determine the nature of the coke formed during the cracking/reforming step. A Ni/Al2O3 catalyst with large Ni particles was found to promote the formation of carbon filaments, whereas on a Ni–K/La2O3–Al2O3 catalyst, with a lower Ni loading and highly dispersed Ni, the carbon was essentially deposited as an amorphous carbon layer.

Thermogravimetric Studies on Pyrolysis and Combustion Behavior of a Heavy Oil and Its Asphaltenes

A thermogravimetric analyzer (TGA) was used to obtain information on the pyrolysis and combustion behavior of both crude oil (Neilburg) and its asphaltenes, each mixed with reservoir sand. Of all the saturate, aromatic, resin, and asphaltene fractions, asphaltenes contribute the most to the formation of coke (fuel). Temperature-ramped as well as the isothermal pyrolysis experiments on whole oil and asphaltenes were analyzed to determine the temperature at which coke formation was maximized. Furthermore, isothermal combustion curves for coke derived from whole oil and asphaltenes were obtained to provide reliable data for calculating the kinetics of the reactions. The classical Arrhenius model was applied, and the activation energy for the combustion of coke formed from pure asphaltenes and from the whole oil was calculated. The results showed that the Arrhenius model fitted the data well in the entire range of temperatures the experiments were conducted. The source material for the coke led to modest differences in its reactivity. The observed activation energy for asphaltenes was 117.7 kJ/mol, and for the whole oil it was 129.5 kJ/mol, which indicates that they were in close agreement. Also, the combustion of coke from asphaltenes showed a reaction order of 0.4 at 375°C, which gradually increased to 0.9 at 525°C. For whole oil, it increased from 0.5 at 375°C to 0.7 at 500°C.

Pyrolysis Analysis and Kinetics of Crude Oils

This research presents the results of an experimental study on the determination of pyrolysis behaviour and kinetics of six crude oils by differential scanning calorimetry (DSC) and thermogravimetry (TG/DTG). Crude oil pyrolysis indicated two main temperature ranges where loss of mass was observed. The first region between ambient to 400°C was distillation. The second region between 400 and 600°C was visbreaking and thermal cracking. Arrhenius-type kinetic model is used to determine the kinetic parameters of crude oils studied. It was observed that as crude oils gets heavier (°API decreases) cracking activation energy increases. Activation energy of cracking also show a general trend with asphaltene content.

Influence of reservoir rock composition on crude oil pyrolysis and combustion

The principal objective of this study was to investigate the influence of reservoir rock composition on the pyrolysis and combustion behavior of crude oils in porous media in relation to in situ combustion (ISC) as a thermal oil recovery process. Using sand pack of varying mineralogical composition and different crude oils, pyrolysis and combustion tests were performed to examine how the clays affect the amount of fuel and its reactivity during the ISC process. From the experimental results, it appears that clay minerals present in the matrix enhance fuel deposition during the pyrolysis process and also catalyze the oxidation of fuel.

Migration behaviour of petroleum-associated short-chain organic acids

In order to increase our understanding of the origin of the short-chain organic acids (SCA) found in oilfield waters, peoperties that influence the possible mechanisms for migration from source rock to reservoir have been examined. The preferential partition of SCA between a synthetic formation water, and a modified crude oil, has been measured and shows the dominance of water solubility. The flooding of a modified petroleum containing SCA through a water-saturated core of reservoir-type rock shows that the pore water has a great capacity for extracting the SCA from the migrating oil phase. These factors make long-distance transport of SCA (dissolved in oil) from source rock to reservoir improbable; also, focused water flow or diffusion processes are not considered realistic mechanisms for long distance transport. In situ sources of SCA are required, and hydrous pyrolysis of crude oil mixed with reservoir type minerals shows that significant amounts of SCA can be generated and that the emplaced petroleum could thus be the source of the SCA found in oilfield waters.

Hydrous pyrolysis of crude oil in gold-plated reactors

Crude oils from Iraq and California have been pyrolyzed under hydrous conditions at 200 and 300°C for time periods up to 210 days, in gold-plated reactors. Elemental (vanadium, nickel), stable isotopic (carbon), and molecular ( n-alkanes, acyclic isoprenoids, steranes, terpanes and aromatic steroid hydrocarbons) analyses were made on the original and pyrolyzed oils. Various conventional crude oil maturity parameters, including 20 S/(20 S + 20 R)-24-ethylcholestane ratios and the side-chain-length distribution of aliphatic and aromatic steroidal hydrocarbons, were measured in an effort to assess the modification of molecular maturity parameters in clay-free settings, similar to those encountered in “clean” reservoirs. Concentrations of vanadium and nickel in the Iraq oil decrease significantly and the V/(V + Ni) ratio decreases slightly, with increasing pyrolysis time/temperature. Whole oil carbon isotope ratios remain fairly constant during pyrolysis, as do hopane/sterane ratios and carbon number distribution of 5 α(H),14 α(H),17 α(H),20 R steranes. These latter three parameters are considered maturity-invariant. The ratios of short side-chain components to long side-chain components of the regular steranes [C 21/(C 21 + C 29 R)] and the triaromatic steroid hydrocarbons [C 21/(C 21 + C 28)] vary systematically with increasing pyrolysis time, indicating that these parameters may be useful as molecular maturity parameters for crude oils in clay-free reservoir rocks. In addition, decreases in bisnorhopane/hopane ratio with increasing pyrolysis time, in a clay-free and kerogen-free environment, suggest that the distribution of these compounds is controlled by either differential thermal stabilities or preferential release from a higher-molecular weight portion of the oil.

Pyrolysis and combustion kinetics of crude oils, asphaltenes and resins in relation to thermal recovery processes

Knowledge of crude oil pyrolysis and combustion kinetics is necessary in oil production for thermal methods of enhanced oil recovery. During oil recovery by in situ combustion, a crude oil undergoes chemical changes (pyrolysis reaction) and physical changes (dilution by the cracking products, vapourization and condensation of some fractions). Both phenomena are important for oil production. This work aims at studying the effect of the oil composition, characterised on the basis of light hydrocarbon, resin and asphaltene contents, on the pyrolysis kinetics of the oil and combustion kinetics of the fuel, examined under idealised reservoir conditions. The results of these investigations show that the colloidal composition of oil as well as the transferability and heat transfer characteristics of the pyrolysis medium have a pronounced influence on the fuel formation and composition.

Identification of Crude Oil Source Facies in Railroad Valley, Nevada, Using Multivariate Analysis of Crude Oil and Hydrous Pyrolysis Data from the Meridian Spencer Federal 32-29 Well

Identification of Crude Oil Source Facies in Railroad Valley, Nevada, Using Multivariate Analysis of Crude Oil and Hydrous Pyrolysis Data from the Meridian Spencer Federal 32-29 Well

Reaction Kinetics of Fuel Formation for In-Situ Combustion

Summary Chemical reactions believed to cause fuel formation for in-situ combustion have been studied and modeled. A thin, packed bed of sand/oil mixture is heated under nitrogen flow at linearly increasing temperatures, simulating the approach of a combustion front. Analysis of gases produced from the reaction cell revealed that pyrolysis of crude oil in porous media goes through three overlapping stages: distillation, mild cracking (visbreaking), and severe cracking (coking). Expressions that govern the rates of the two cracking reactions are derived, and a technique is outlined to obtain initial estimates for their parameters from the experimental data. The parameters of a proposed distillation function, as well as refined estimates for the cracking reaction parameters, are obtained by non-linear regression methods based on an overall kinetic model. Successful matching of the experimental data, including the total amount of fuel deposited, was achieved with this model. It was found that fuel formation was a result of two successive cracking reactions that the oil undergoes at temperatures above 280° C [536°F]. Also, distillation of crude oil at temperatures below 280°C [536°F] played an important role in shaping the nature and extent of the cracking reactions. The operating pressure and the rate of heating of the sand/oil sample were found to affect the fuel-formation process only through the influence exerted on distillation. Clay minerals showed a catalytic effect on the cracking reactions, especially coking. Finally, the asphaltene fraction of a crude oil was found to correlate with the fuel content of that oil.

Influence of certain parameters on oxidative pyrolysis of crude oil

1. In a flow-type laboratory unit (reactor volume 3 liters), the process variables have been studied in the oxidative pyrolysis of crude oil from the Sosnino field; it has been shown that, under optimal process conditions (790°C, contact time 0.6 sec, steam ∶ oil ratio 0.5, and oxygen ∶ oil ratio 0.15), the yield of gaseous olefins is 44.4% by weight, including 21.1% ethylene. 2. The technical feasiblity of this process was demonstrated by a 240-h test in the laboratory unit.

Crude Oil Pyrolysis for Olefin Production (Part 2)

Minas crude was subjected to pyrolysis in a fluidized bed reactor containing carbon particles as heat carrier and the products yields therefrom were compared with that from Kuwait crude reported in the previous paper. Minas crude of paraffinic base was found less refractory than Kuwait crude of mixed base, giving better olefins yields. Within the pyrolysis conditions used in the experiment, the highest ethylene yield of 33wt% on crude was obtained at 850°C, 0.2sec, while the highest propylene yield of 16wt% at 750°C, 0.2sec. Less amount of aromatics in total was obtained from Minas crude compared with Kuwait crude. The difference in the product distribution was suggested to be interpreted in terms of hydrocarbon constituents in crude oils, or more conceptually, the base to which they belong.

Crude Oil Pyrolysis for Olefin Production (Part 1)

By use of a fluidized bed reactor containing carbon particles as heat carrier, pyrolysis of Kuwait crude was studied to manufacture olefins. The experimental conditions covered the ranges of temperature 750-900°C, of residence time 0.2-1sec, and of steam dilution ratio 0.5-2 by weight to crude oil. These operating variables were examined to effect the respective yields of olefins and aromatics. In the experiment, the best yield of ethylene of 26wt% on crude was obtained at 850°C, 0.5sec, whereas the best propylene yield was 15wt% at the less severe conditions of 750°C and 0.6sec. Total aromatics yield including benzene and naphthalene ranged between 8-20wt% on crude. Use of hydrogen as diluent instead of steam was found effective for the increased production of ethylene, which was accompanied by the decreases in propylene and butadiene yields.

Crude Oil Pyrolysis for Olefin Production (Part 3)

Seven kinds of crude oils with a wide variety of properties as well as six fractions of Kuwait crude oil distillation were pyrolyzed to yield olefins in a fluidized bed reactor at 800°C and steam dilution of 1:1. The plot of the product yields against characterization factors (K=3√T'B/d', T'B=molar average boiling point in °R, d'=sp. gr. 60/60°F) of the respective feed oils were found to form straight lines, which seemingly provide a means to estimate the product distribution from pyrolysis of unknown crude. The changes in the product yield by the progress in pyrolysis severity were interpreted in terms of intensity function (IF=T•θ0.06, T=pyrolysis temperature in °F, θ=residence time in sec). This was done with respect to experimental results of Kuwait and Minas crude respectively. This may also offer a guidepost for the choice of pyrolysis conditions to obtain a specific set of product yields from any crude. Distribution of sulfur and heavy metals in crude into the pyrolysis products was also examined.

Studies on Crude Oil Pyrolysis

Studies on Crude Oil Pyrolysis