High Temperature Hydrocarbon Research Articles

Formation of a Porous Crystalline Mg1‒ x Al2O y Overlayer on Metal Catalysts via Controlled Solid-State Reactions for High-temperature Stable Catalysis.

Catalyst deactivation by sintering and coking is a long-standing issue in metal-catalyzed harsh high-temperature hydrocarbon reactions. Ultrathin oxide coatings of metal nanocatalysts have recently appeared attractive to address this issue, while the porosity of the overlayer is difficult to control to preserve the accessibility of embedded metal nanoparticles, thus often leading to a large decrease in activity. Here, we report that a nanometer-thick alumina coating of MgAl2O4-supported metal catalysts followed by high-temperature reduction can transform a nonporous amorphous alumina overlayer into a porous Mg1‒xAl2Oy crystalline spinel structure with a pore size of 2‒3 nm and weakened acidity. The high porosity stems from the restrained Mg migration from the MgAl2O4 support to the alumina overlayer through solid-state reactions at high temperatures. The resulting Ni/MgAl2O4 and Pt/MgAl2O4 catalysts with a porous crystalline Mg1‒xAl2Oy overlayer achieved remarkably high stability while preserving much higher activity than the corresponding alumina-coated Ni and Pt catalysts on MgO and Al2O3 supports in the reactions of dry reforming of methane and propane dehydrogenation, respectively.

Analysis of wave propagation in non-isothermal poroelastic solids saturated by two-phase fluids

SUMMARY This work presents a model to characterize the behaviour of waves propagating in non-isothermal poroelastic solids saturated by two-phase fluids. The dynamic differential equations include the poroelasticity and heat equations with the solid, fluid and thermal fields combined using coupling terms. A plane wave analysis shows that five waves can propagate, three compressional, one fast (P1) and two slow (P2, P3), a shear fast (S) and a thermal slow (T). P2, P3 and T are diffusive waves at low frequencies, while P1 and S behave as propagating waves. The T wave is coupled with the compressional waves and uncoupled with the S wave. The plane wave analysis applied to a real sandstone saturated with gas–water mixtures compares phase velocities and attenuation factors for two-phase and effective single-phase fluids, considering or neglecting the coupling terms. It is observed that P1 and P2 waves have higher velocities for coupled cases, while P3 and T waves exhibit the opposite behaviour. Furthermore the plane wave analysis is performed in the coupled case for oil–water and gas–water two-phase fluids, with compressional waves exhibiting higher velocities for gas–water than for oil–water mixtures. The propagation of waves in a 1-D thermo-poroelastic medium saturated by a gas–water mixture is presented and analysed using a finite element procedure. Considering temperature may become important in high-pressure high-temperature hydrocarbon and geothermal reservoirs.

Encapsulating commercial accelerometers with epoxy and fluoroelastomer for harsh hydrocarbon fluid environment.

Traditionally, in the oil and gas industry, accelerometers are mounted externally on motors for condition monitoring of vertically suspended, closed suction hydrocarbon pumps due to their inability to withstand harsh downhole environments, preventing the detection of impeller failures. This study addresses the need for encapsulation solutions for accelerometers submerged in hydrocarbon fluid environments. It evaluates the feasibility of epoxy and fluoroelastomer as encapsulation materials for long-term immersion in high-temperature hydrocarbon fluid and determines their impact on the accelerometer's performance. Extensive testing involved submersion in high-temperature hydrocarbon fluid at 150°C for over 10,000h and six months in brine. Material characterization, including mass variation, microscopic imaging, and FTIR spectroscopy, revealed negligible degradation. Encapsulated accelerometers effectively detected vibrations with an acceptable alteration in amplitude. In comparison with commercial alternatives, our encapsulation outperformed them. While oil traces became evident within just 24h in the alternatives, our solution exhibited no signs of leakage. This research pioneers a novel packaging solution employing epoxy and fluoroelastomer for side-exit commercial sensors tailored for high-temperature hydrocarbon fluid applications, addressing a critical gap in the industry. Our work enhances reliability and safety for vertical oil pump condition monitoring in downhole applications, benefiting the oil and gas sector.

How stable is LiNi0.8Co0.15Al0.05O2 under high-temperature hydrocarbon ceramic fuel cell conditions?

LiNi0.8Co0.15Al0.05O2 (LNCA) is an important cathode material optimized for room-temperature operation of lithium-ion batteries (LIBs). As an emerging research area, LNCA was recently applied as electrodes (both cathode and anode) for high-temperature ceramic fuel cells (CFCs) with impressive performances. This raises a critical question: How stable is LNCA as a CFC anode under methane-fueled conditions (i.e., in CH4 and CO2 at high temperatures)? Herein, we investigated the structure stability of LNCA in CH4 and CO2 at a wide temperature range of 100–800 °C. The corresponding gas-solid reaction equations under these conditions were proposed for the first time. It was found that LNCA started to react with CH4 at 500 °C, leading to its decomposition into Li2CO3, NiO/CoO solid solution, Ni/Co alloy, and LiAlO2. The NiO/CoO solid solution was further reduced into Ni/Co by CH4 at 600 °C. Furthermore, CO2 could make LNCA decomposed into Li2CO3, NiO/CoO, and Al2O3 at 600 °C or above. These findings can be used to design Ni/Co-based anodes for CFCs with LNCA.

Research of the Thermal Effect on the Fe-Cr-Al Alloy Foil in the Initial State and with the Supported Secondary Carrier

Iron and chromium based alloys have found wide application in various fields of science and technology. A primary carrier based on Fe-Cr-Al alloy is used in block catalysts for high-temperature hydrocarbon conversion, in production of block metal catalysts for neutralization of toxic gases released during operation of internal combustion engines, as well as those present in smoke emissions from enterprises. The influence of thermal action on Fe-Cr-Al alloy foil and stability of the secondary carrier on its surface was studied. The elemental composition of the surface layer of Fe-Cr-Al alloy foil does not remain constant during heating and depends on the thermal treatment mode. Some of the elements come to surface and the elemental composition of the surface layer can differ significantly from that observed in the bulk of the foil sample. This implies the possibility of changing the adhesive and adsorption properties of the foil surface, as well as the need to take this fact into account when supporting a secondary carrier and active phase to the foil. An applied technique of phosphating and supporting a secondary carrier at the foil surface makes it possible to obtain a sufficiently stable coating. There is no shedding of the secondary carrier from the foil surface during high-temperature treatment in air.

A new robust regenerative turbo-reactor concept for clean hydrocarbon cracking

Energy consumption in the chemical and petrochemical industries is dominated by the highly energy-intensive, high-temperature hydrocarbon cracking process. This paper offers an attractive solution to potentially decarbonise the cracking industry by direct renewable electrification whilst also improving the efficiency of energy transfer and enhancing the quality of the overall cracking process. Controlled endothermic cracking reactions are generated by direct mechanical energy transfer using a new electric-motor-driven turbo-reactor to replace the fossil-fuelled radiant unit in the conventional cracking plant. This study provides an introduction to the novel concept, focusing on how the unique three-blade-row repeating stage design is exploited in order to drive the efficient energy transfer and transformation processes used to overcome the fundamental limitations of the conventional process. More specifically, this includes increasing the primary product yield, mitigating coke deposition and improving operability. A combination of URANS and high-fidelity LES are presented in order to probe the aerothermal flow physics and interactions in the rotor and diffuser. This study clearly demonstrates how the working principals of the elemental stage can be realised uniformly across the full regenerative turbo-reactor by exploiting the robust and naturally self-adjusting concept. This work highlights the high-level of controllability of the turbomachine, which allows the cracking environment and species selectivities to be tailored during operation, for example, by conducting minor alterations to the rotational speed.

Modelling the formation, growth and coagulation of soot in a combustion system using a 2-D population balance model

A 2-D population balance model utilizing carbon mass and surface sites as internal variables was developed for soot formation during hydrocarbon decomposition reactions. The model provides particle properties such as composition and mean polyaromatic hydrocarbon size, enabling the incorporation of cyclization reactions, soot maturation, and a dynamic model of surface reactions. Accompanied by a reduced kinetic model for gas-phase species, this population balance model was then discretized using the fixed-pivot method, to provide predictions of the soot distribution as a function of position within a plug flow reactor. The model predictions of the particle size distribution functions resulting from high-temperature hydrocarbon pyrolysis within a PFTR system provide good comparison with experimental measurements under a variety of conditions. In addition to this, by tracking the changes in particle composition occurring through cyclization reactions, the point of carbon particle maturity could be determined, allowing subsequent predictions of the size distributions of the primary particles comprising soot aggregates. Through comparison with TEM and SEM imaging, these primary particle distributions were found to be accurate for the experimental conditions examined. While the implementation of the second internal variable describing particle composition was not found to provide substantial improvements to the prediction of the overall aggregate distribution from existing models, the additional computational cost that accompanies additional variables is justified in applications where morphological predictions of particle aggregates are of interest, in addition to their size distribution.

Curie Point Depth, Heat Flow and Geothermal Gradient Determined from Analysis of Aeromagnetic Data over parts of the Lower Benue Trough and Anambra Basin, Nigeria

This paper evaluates the aeromagnetic data over parts of the Lower Benue Trough and Anambra Basin of North central and Southeastern Nigeria obtained from the Nigerian geological Survey Agency, Abuja to quantitatively determine the Curie Point Depth, Geothermal gradient, and Heat flow using Oasis montaj software, Fourpot software, and Surfer software. The results revealed that the average Curie point Depth of the Study area is 8.07594 km, the Geothermal gradient obtained has an average value of 73 oC/km, areas with low and intermediate geothermal gradient are, Southeast of Obubra, Northeast of Obi, North West of Odolu, and Awgu. The study area has an average heat flow of 170 mW/m2 , it is observed from the map that the areas around Igunmale, Abakaliki, Udi, Ejekwe and some area around Nkanu East have high heat flow rate attributed to presence of intrusive rock. Consequently, the study area is characterized by low, intermediate and high magnetic anomalies, the most prominent trend observed is in the ENE -WSW and NE – SW minor trend direction and has high heat reservoir potential which can be harnessed as geothermal energy, there is also a possibility of high temperature and pressure hydrocarbon reservoir potential.

Investigation of the 0.4C-35Cr-45Ni-Nb Alloy after Service in High-Temperature Steam and Hydrocarbons Environment.

The paper presents the results of investigation of the 0.4C-35Cr-45Ni-Nb alloy, which operated in the cracked hydrocarbon feeds and dilution steam at 1125 °C. The material originated from the pyrolytic furnace coil tubes, of which internal walls were in contact with the aforementioned medium, whereas the external walls were in contact with the flue gases. The examination included metallographic and mechanical tests on the material after service exposure, the results of which were compared with the ones obtained for the as-received non-exposed specimens. The metallographic tests revealed changes in the alloy’s structure manifested by formation of significant amount of the carbides due to carburization of the alloy from the steam and cracked hydrocarbon feeds side. The central and external parts of the alloy samples (having no contact with the process medium) underwent substantial degradation but within a relatively narrow zone of the material. The investigations of hydrogen and methane content in the alloy showed a high amount of these gases, resulting from high-temperature corrosion in steam environment. The mechanical tests demonstrated clear shortening of the plastic deformation range of the alloy due to penetration of the gases and formation of the carbides inside the material’s structure. A low level of corrosion and no creep mechanism were detected.

Synthesized graphene oxide and fumed aerosil 380 dispersion stability and characterization with partially hydrolyzed polyacrylamide

Hydrolyzed polyacrylamide (HPAM) is a commonly used polymer for the chemicals, mining and refining processes of hydrocarbon but suffers from a persistent high-temperature instability problem. In contrast, the nanoparticle suspension remains a technical challenge because of the strong interactions of van der Waal forces within nanoparticles, which always encourage aggregation. This research sought to improve nanoparticles (NP) stability and polymer (HPAM) rheological properties to improved hydrocarbon recovery by utilizing synthesized graphene oxide (GO) nanosheets and fumed Aerosil 380 Silica oxide (SiO2). The aqueous nanocomposites based on HPAM-GO and HPAM-SiO2 in aqueous polymeric solutions have been developed, and its viscoelastic and static behaviour is studied. The results imply that by adding fumed silica NP, the viscoelastic behaviour of HPAM is marginally improved, particularly in high temperatures and salinity, however, the inclusion of GO's significantly improves the viscosity and stability of the base polymer fluid at high temperatures. The Fourier data for the transformation of the infrared spectrum confirmed that the hydrogen bonding formed between HPAM carbonyl groups and silica NP surface silanol functionality and covalent interlinking of electrostatic h-bonding between HPAM and functional GO contributed to the improved stabilization and improved rheological performance that helps to recover high salinity and temperature hydrocarbons.

Characterization of waste engine oil derived pyrolytic char (WEOPC): SEM, EDX and FTIR analysis

Waste Engine oil (WEO) thermal degradation was conducted at temperature levels from 450 °C to 575 °C. We studied the impact of temperature on oil, char, and gas yield. The effect of temperature on the characteristic properties of char such as surface morphology, elemental composition was perceived. It was observed that the temperature has positive upshots on the decomposition of some of the metal content in the WEO, not for all. The existence of metals in the char was observed. The incidence of high-temperature hydrocarbons along with other compounds were confirmed from the FTIR analysis.

A Review of Terminology Used to Describe Soot Formation and Evolution under Combustion and Pyrolytic Conditions.

This review presents a glossary and review of terminology used to describe the chemical and physical processes involved in soot formation and evolution and is intended to aid in communication within the field and across disciplines. There are large gaps in our understanding of soot formation and evolution and inconsistencies in the language used to describe the associated mechanisms. These inconsistencies lead to confusion within the field and hinder progress in addressing the gaps in our understanding. This review provides a list of definitions of terms and presents a description of their historical usage. It also addresses the inconsistencies in the use of terminology in order to dispel confusion and facilitate the advancement of our understanding of soot chemistry and particle characteristics. The intended audience includes senior and junior members of the soot, black carbon, brown carbon, and carbon black scientific communities, researchers new to the field, and scientists and engineers in associated fields with an interest in carbonaceous material production via high-temperature hydrocarbon chemistry.

Dynamic thermo-physical characteristics of high temperature gaseous hydrocarbon fuel thermal power generation for regeneratively cooled hypersonic propulsion system

Power generation is urgent needed by the hypersonic air-breathing propulsion system, but the on-board power generation method is heavily restricted by its special structure. The outlet high temperature hydrocarbon fuel of the cooling channel in the hypersonic propulsion system can be used to generate power. However, the hydrocarbon fuel temperature is highly related with hypersonic propulsion system dynamic working conditions. To analyze the dynamic thermos-physical characteristics of high temperature hydrocarbon fuel thermal power generation (TPG) system, a zero-dimensional dynamic analytical model was developed, dynamic characteristics of the TPG system under different working conditions were conducted. Results show that there is overshoot of outlet fuel temperature under flight Mach number increase conditions and fuel equivalence ratio decrease conditions, which can be more than 10 K. Whilst there are both negative and positive overshoot of the generated power under the above working conditions, the largest magnitude of negative and positive overshoot can be more than 1 kW. Furthermore, the dynamic time of outlet fuel temperature and generated power are about 20–30s. Such complexity of dynamic characteristics brings difficulties in fuel supply for the propulsion system.

XAFS Analysis of Fe and C Atoms Property at Carburizing from Oxidized High Purity Fe Foil in High Temperature Hydrocarbon Gas

XAFS Analysis of Fe and C Atoms Property at Carburizing from Oxidized High Purity Fe Foil in High Temperature Hydrocarbon Gas

Effect of Gain in Soil Friction on the Walking Rate of Subsea Pipelines

Subsea pipelines are commonly employed in the offshore oil and gas industry to transport high-pressure and high-temperature (HPHT) hydrocarbons. The phenomenon of pipeline walking is a topic that has drawn a great deal of attention, and is related to the on-bottom stability of the pipeline, such as directional accumulation with respect to axial movement, which can threaten the security of the entire pipeline system. An accurate assessment of pipeline walking is therefore necessary for offshore pipeline design. This paper reports a comprehensive suite of numerical analyses investigating the performance of pipeline walking, with a focus on the effect of increasing axial soil resistance on walking rates. Three walking-driven modes (steel catenary riser (SCR) tension, downslope, and thermal transient) are considered, covering a wide range of influential parameters. The variation in walking rate with respect to the effect of increased soil friction is well reflected in the development of the effective axial force (EAF) profile. A method based on the previous analytical solution is proposed for predicting the accumulated walking rates throughout the entire service life, where the concept of equivalent soil friction is adopted.

Development of 99Mo-alfa-benzoin oxime complex as industrial radiotracer for identification of leaky heat exchanger and its validation with 99mTc

Molybdenum-99 (99Mo), in the form of 99Mo-alfa-benzoin oxime (99Mo-ABO) complex was developed as industrial radiotracer and its performance was tested in a diesel hydro-treater unit of a leading oil refinery. Main objective of the study was to evaluate the suitability of the developed 99Mo-ABO complex for industrial applications at high temperature and high-pressure hydrocarbon stream. A methodology was developed to convert the aqueous solution of fission 99Mo into 99Mo-ABO complex, suitable for mixing with organic phase. A radiotracer study was carried out to identify the leaky heat exchangers from a series of four heat exchangers using 99Mo-ABO complex in organic phase as a novel industrial radiotracer. Reproducibility of the result was verified by using 99mTc in organic phase as another radiotracer. From the study it was found that the developed radiotracer ‘99Mo-ABO complex’ is suitable for industrial applications at high temperature and high-pressure hydrocarbon streams.

Modelling nonlinear time-dependent pipeline walking induced by SCR tension and downslope

Subsea pipelines are important facilities in offshore oil and gas industry to transport High-Pressure and High-Temperature (HPHT) hydrocarbon. They are often exerted by cyclic thermal loading through the whole operational life, which may trigger asymmetry in the effective axial force (EAF) profile, leading to a global axial movement, defined as ‘pipeline walking’. It may cause the downtime and structural risks, since this directional accumulation in axial movement results in the overstressing of end connection, loss of tension in a steel catenary riser (SCR) and other issues in the field, therefore subsea pipeline design requires a reliable estimate of the global pipeline walking rate. Current design methods adopt a constant soil friction coefficient and ignore variations in soil-pipeline interaction with time during the heating up and cooling down processes. In reality, the overlooked changing soil friction is important, and may alter the pipeline walking behaviours. To achieve an accurate assessment of pipeline walking, this paper advances the conventional design practice, by introducing a time-dependent axial soil friction function, to examine the pipeline walking behaviour over the operational thermal cycles. A suite of time-dependent matrixes is provided to reveal the development of the expansion/contraction of the pipeline, the corresponding mobilised soil frictions and the EAF profile. The significant nonlinear EAF profile in response to the time-dependent soil friction is examined, and is used to well assess the accumulation in pipeline walking rate. The proposed analytical framework is applied into case studies to demonstrate its validity and applicability in practice.

Direct hydrocarbon fuel cells: A promising technology for improving energy efficiency

The world's first fuel cell described in the early 1800's was fueled with hydrogen. While hydrogen is still the most common fuel, hydrocarbon fuels offer several advantages including availability at a lower cost, higher storage density and existing infrastructure. This paper provides an overview for the significant potential benefits of using hydrocarbon fuels directly in a fuel cell system. Their use leads to a reduction in the capital cost due to the elimination of the fuel processor unit. The fundamentals, advantages, types of direct hydrocarbon fuel cells (DHFC), challenges and applications are discussed in this paper. The past and current status of research and development activities are addressed with emphasis on efficiency and exergy analyses. In spite of their high theoretical energy efficiency, technical challenges remain unsolved in DHFC systems. In high temperature hydrocarbon fueled operation, the deposition of carbon-based material leads to fuel cell degradation. In lower temperature fuel cells, electrode (mainly the anode) over-potentials and fuel crossover are still challenging. Therefore, the improvement and commercialization of these types of fuel cells will probably require the development of less or non-noble catalysts and reasonably functioning membranes.

A multi-wavelength speciation framework for high-temperature hydrocarbon pyrolysis

A framework for the study of high-temperature hydrocarbon pyrolysis is presented. The proposed framework details a multi-wavelength speciation method using convex optimization, a review of complementary fixed-wavelength laser diagnostics, and a database of high-temperature absorption cross-sections to enable use of the framework for 11 different species. The proposed speciation method involves a vectorized Beer-Lambert system solved under solution constraints using convex optimization. In support of the proposed method, a review of pertinent laser diagnostics and a database of high-temperature absorption cross-sections are also provided. The database includes measured absorption cross-sections of methane (CH4), ethylene (C2H4), propene (C3H6), isobutene (i-C4H8), 1-butene (1-C4H8), benzene (C6H6), toluene (C7H8), and four jet fuels (samples of Jet A, JP5, JP8, and Gevo ATJ) at the wavelengths of 3.1758 µm, 3.17595 µm, 3.283 µm, 3.392 µm, 3.410 µm, 10.532 µm, 10.675 µm, 10.89 µm, 10.958 µm, 10.962 µm, and 11.345 µm within the range of 300–1600 K and 0.25–4 atm. The database is comprised of over 1000 high–temperature absorption cross-section measurements from new shock tube experiments, new Fourier transform infrared spectrometer (FTIR) experiments, and an aggregated dataset from the literature. The convex speciation method and cross-section database provided will facilitate laser absorption studies of hydrocarbon pyrolysis used in the development of chemical kinetic mechanisms.

Experimental study on the thermodynamic characteristics of the high temperature hydrocarbon fuel in the cooling channel of the hypersonic vehicle

Cooling is one of the key technologies for the scramjet considering the enormous thermal load and the demand of reusable long-range mission. In the regenerative cooling process, hydrocarbon fuel flows through the cooling channel, gets heated and experiences severe thermal properties changes. The compressibility of fuel becomes non-negligible and possible dynamic process emerges, which affects both the characteristics of fuel cooling and fuel mass flow control. As a result, the dynamic characteristics of the high temperature hydrocarbon fuel within the cooling channel must be carefully studied. In this work, experiments are conducted at different simulated engine working conditions. The settling time of pipe pressure drop is used to characterize the dynamic process of the outlet fuel mass flow, because the outlet temperature of the fuel is too high to measure the fuel mass flow directly. In conditions of the variation of inlet fuel mass flow and backpressure disturbance, overshoot of the pressure drop is observed and the magnitude of which varies with the working conditions. The settling time of outlet fuel temperature and wall temperature channel firstly increases, then decreases with the increase of the outlet fuel temperature. The settling time of both outlet fuel temperature and wall temperature increases with the increase of the heating heat flux. The experimental results in this work are expected to provide supports to the engine control system design.