Cracking Process Research Articles

Thermal cracking of effective decontamination and recycling of lubricating oil: mechanisms, conditions, and performance enhancements

Abstract Thermal cracking of SAE 40 lube oil contamination is a critical process for maintaining the efficiency and longevity of industrial machinery and automotive engines. This study investigates the mechanisms and outcomes of thermal cracking as a method to decompose and remove contaminants from lube oil (SAE40) and investigates the possibility of the use of solid coke produced as residue after the cracking process. The research also examines the optimal conditions for thermal cracking, including temperature ranges, heating rates, and the influence of catalysts. Analytical techniques such as thermogravimetry (TGA), Fourier-transform infrared spectroscopy (FTIR), and thermograms (DSC) are employed to characterize the chemical composition of the solid produced after treatment. This result reveals that the produced coke after the treatment demonstrates the resin capability, and it can be used as a binder or additive in lower temperature applications. This study underscores the potential of thermal cracking as an effective method for recycling contaminated lube oil, thereby contributing to sustainability and cost-efficiency in industrial maintenance practices.

Chromite–Zeolite Catalysts for Syngas Conversion to Hydrocarbons: Insights into Oxide–Zeolite Interactions

AbstractA key challenge in modern society is developing the sustainable processes for producing vital chemicals, such as hydrocarbons, from renewable raw materials. The OX‐ZEO process, which uses bifunctional catalysts to convert syngas into hydrocarbons, offers a potential alternative to the nonsustainable cracking process. Combining oxide materials with zeolites enables the direct synthesis of various hydrocarbon products with high selectivity. However, challenges remain, particularly regarding carbon monoxide (CO) conversion and unwanted carbon dioxide (CO2) generation. This study explores the impact of bimetallic chromites combined with H‐MOR zeolite on the reaction outcome. Comparative experiments using only the oxide versus the bifunctional catalyst revealed a clear link between the methanol synthesis activity of the oxide and the overall activity in the OX‐ZEO process. Furthermore, catalytic tests with monometallic oxides paired with H‐MOR highlighted the role of the oxide's crystal structure in syngas conversion. These findings offer insights into the oxide–zeolite interactions, enabling the development of improved catalyst combinations that enhance the CO conversion, reduce CO2 formation, and maintain high product selectivity.

SUBSTITUTION FOR MACKEREL FISH (Scomberomorus commerson) BONE MEAL ON FISH CRACKERS

Fish bones are only considered waste by the community, even though they have good nutritional content, so they can be used as fish bone flour as an ingredient for fish crackers. To ensure the quality characteristics of fish crackers that have been substituted between fish bone flour and tapioca flour in fish crackers. Stages of the mackerel fish bone flour manufacturing process: preparation of raw materials for mackerel fish bones, boiling 1, washing, softening, boiling 2, baking, and flouring. Stages of the cracker processing process are: preparation of raw materials, washing fish, filleting, scraping meat, grinding, substitution of mixing fish bones and dough, forming, steaming, cooling, cutting, drying, baking, then frying. The results of the proximate analysis of fish bones showed water content of 5.77%, ash content of 60.20%, protein content of 11.26%, fat content of 2.58%, calcium content of 29.83%, ALT of 3.90x104 colonies/gram. The water content of the crackers produced ranged from 2.57% to 4.17%, the acid insoluble ash content of 0.05% to 0.41%, the protein content of 2.19% to 5.04%, the calcium content of 0.06% to 4.22%. The results of statistical analysis showed that there was an effect of mackerel fish bone flour substitution on water content, ash content, protein content, and calcium content. The Total Plate Count of crackers in all treatments obtained results <2.5x102 colonies/gram. The selected product in the P3 formulation with a calcium content of 4.22% increased the calcium content by 400%. The best sensory test of the formulation at P3 with 30 panelists on the parameters of appearance, odor, taste, and texture was still acceptable to the panelists.

Potential of Local Microorganisms Solution from Chicken Manure as a Bioactivator in Liquid Waste Treatment from the Fish Cracker Processing Industry

The wastewater produced by traditional food industry is a source of problem due to its high levels of organic compounds pollutant that can increase the level of chemical oxygen demand (COD) and biological oxygen demand (BOD) values that exceed the established wastewater quality standard thresholds. The difficulty in removing high concentrations of organic material through conventional waste treatment necessitates the use of special treatment methods using local microorganisms’ solution as bioactivators to accelerate the decomposition of organic compounds. This research aims to identify bacteria in local microorganisms’ solution with potential applications in reducing organic compounds by its enzymatic activities. Based on the research results, among the 42 isolates examined, six isolates demonstrated the ability to hydrolyze starch, protein and fat based on qualitative tests. These isolates belong to the genus Bacillus based on partial sequencing of 16S rRNA gene. The qualitative tests confirmed the potential of these isolates as they exhibited enzymatic activities that showed potential to reduce organic compounds.

IMPROVEMENT OF CATALYTIC CRACKING FOR DEEPEN OF OIL REFINING

At the moment, there is a situation in the world in which the volume of proven reserves of light oils is decreasing, and the volume of reserves of heavy oils are increasing. The processing of heavy hydrocarbons is becoming more complicated and does not provide the necessary depth of extraction of light distillates. Large capital expenditures are required to ensure the specified oil refining depth parameter.The deepening of oil refining is developing through the development and implementation of flexible technological schemes and advanced high-intensity environmentally friendly thermocatalytic and hydrogenation processes for deep processing of vacuum gas oils and oil residues, which include catalytic cracking.Catalytic cracking allows not only to increase the depth of oil refining, but also to ensure the production of a high-octane component of commercial gasoline. In addition, the products are gases rich in propane-propylene and butane-butylene fractions which are used as raw materials for petrochemical synthesis and production of motor fuel components.Currently, the problem of improving the catalytic cracking process is quite acute, because at existing installations, catalytic systems are being replaced with domestic analogues, the raw materials of the process are becoming heavier due to the use of deep vacuum distillation of oil and the need for high-quality commercial products and petrochemical raw materials is increasing.Therefore, the paper proposes to use a modeling method to predict the process indicators. The mathematical model will allow us to develop technical solutions to optimize the operation of the catalytic cracking unit in order to increase the depth of processing of hydrocarbon raw materialsBased on monitoring the operation of an industrial catalytic cracking plant, experimental dependences of the effect of process parameters on the yield of target products were obtained, systems of differential equations of material balance were developed, experimental and calculated data on the model were compared.Regression analysis was used to determine the existence of dependence, and the correlation method was used to describe the nature of the relationships. The main parameters of the catalytic cracking process are described, such as temperature, pressure drop, catalyst level and steam consumption. The dependences of the output parameters on each other (gasoline, butane-butylene and propane-propylene fractions) were revealed. The model is obtained in the form of a generalized formula based on a combination of complex methods in the analysis. The adequacy of the obtained equation has been confirmed using existing software. A new software solution has been proposed for the selection of optimal process parameters based on the previously compiled model.

Stochastic Extension of Nonlocal Macro–Mesoscale Consistent Damage Model for Fracture Behaviors of Concrete Materials

The nonlinearity and randomness in composite materials such as concrete present challenges regarding the safety analysis and reliability-based design of structures. Based on two-scale damage evolution and physically based geometry–energy conversion, the nonlocal macro–mesoscale consistent damage model (NMMD) shows a unique capability in dealing with the nonlinearity of crack evolution. In this paper, a stochastic extension of the NMMD model is proposed to analyze the stochastic fracture behaviors of concrete materials. The extended model uses the stochastic harmonic function (second kind) to represent the spatial variability in concrete properties and thus to investigate the influence of inhomogeneity in the cracking process. Numerical examples of three-point bending beams without defects and with initial cracks of various sizes demonstrate that the stochastic NMMD model is capable of not only capturing uncertain fluctuations in peak load but also simulating the random walk of the crack path with the instantaneous transition of fracture modes, as observed in experiments. In addition, the effectiveness of the stochastic NMMD model with only a single random field (i.e., Young’s modulus) also contradicts the conventional assertion that stochastic simulations of quasi-brittle fracture should contain at least two mechanical properties with spatial randomness. Finally, the investigation of fracture energy with stochastic fluctuations reveals that randomness resulting from heterogeneity can statistically improve the fracture toughness of concrete materials to some extent.

Coupling of discrete and smeared cracking models applied to reinforced concrete structures

The nonlinearity inherent to concrete comes from the cracking process and the inelastic phenomena in the fracture process zone (FPZ). It is understood that initially, microcracks appear diffusely in the material medium, even under low-intensity loading conditions. In these initial stages, cracking develops stably, causing the structure's nonlinear response, which can still absorb loads. With the advancement of the process, the crack coalescence causes the significant growth of cracks so that a discontinuity in the material medium is observed. At this stage, propagation occurs in an unstable manner, and the structure loses the ability to absorb loads. In reinforced concrete, the manifestation of cracks occurs through multiple fronts due to the reinforcement steel that absorbs tensile forces and locally contains the crack propagation, which initially appears in regions not covered by the reinforcement steel. In more advanced stages, cracks can be observed that surpass the reinforcement steel region and propagate throughout the structure until its collapse. Over the years, two main approaches have stood out in the representation of concrete fracturing: smeared crack models and discrete crack models. Each model aims to represent the concrete response based on different hypotheses. In the smeared models, the medium is considered continuous, and the effects of cracking are represented by the elastic degradation of the material computed through constitutive models. In discrete models, the crack is represented by a material discontinuity inserted into the mesh. This work presents a strategy that combines smeared and discrete models applied to the modeling of flat reinforced concrete structures. The reinforcement steel will be represented by one-dimensional elements with elastoplastic behavior while maintaining the perfect bond between the steel rebar and concrete. In the representation of concrete fracturing, the FPZ will be represented by a scalar damage model for the continuous degradation of the material, and from a critical damage value, a discrete model, which considers multiple crack fronts, is activated by inserting a discontinuity into the mesh using a nodal duplication strategy, thus describing the final rupture process. Finally, numerical simulations will be presented to illustrate the model's performance.

Determination of Lactoferrin Using High-Frequency Piezoelectric Quartz Aptamer Biosensor Based on Molecular Bond Rupture.

In this study, an aptamer biosensor for detecting lactoferrin (LF) was developed using piezoelectric quartz-induced bond rupture sensing technology. The thiol-modified aptamer I was immobilized on the gold electrode surface of the quartz crystal microbalance (QCM) through an Au-S bond to specifically bind LF. It was then combined with aptamer-magnetic beads to amplify the mass signal. The peak excitation voltage was 8 V at the resonance frequency for the 60 MHz gold-plated quartz crystal. When the molecular bond cracking process occurred, the aptamer-magnetic beads combined on the surface of the piezoelectric quartz were removed, which resulted in an increase in quartz crystal resonance frequency. Therefore, the specific detection of LF can be realized. Under optimized experimental conditions, the linear range for LF was 10-500 ng/mL, the detection limit (3σ) was 8.2 ng/mL, and the sample recoveries for actual milk powder samples ranged from 97.2% to 106.0%. Compared with conventional QCM sensing technology, the signal acquisition process of this sensing method is simple, fast, and easy to operate.

Heterogeneity Modelling of Concrete Structures by Nonlocal Damage Models

The behavior of structural concrete is usually represented by considering the homogeneous material media and its macroscopic properties. The problem can be represented in more realistic models considering the material as a heterogeneous multiphase media. In representing heterogeneity, either a direct or indirect description of the phases can be considered. The direct approach considers the phases to be geometrically described in the discrete model. In the indirect approach, phases are represented by homogenizing their physical properties or by the random distribution of points in the domain with material parameters corresponding to each phase. In the physically nonlinear analysis using the Finite Element Method, a constitutive model capable of differentiating the response to tension and compression and computing the gradual cracking process of the concrete is necessary. Furthermore, these models must be coupled with regularization mechanisms to deal with numerically induced localization problems, such as the nonlocal approach. Given the above, this work proposes a model for representing the heterogeneity of concrete aiming at the physically nonlinear analysis of structures. Two phases will be considered to describe the heterogeneity: the cement matrix and the coarse aggregates, which will be incorporated into the discrete model using a hybrid method, which combines characteristics of direct and indirect methods. For material media degradation, a non-local damage model will be adopted with appropriate constitutive laws for each constituent material. Finally, numerical simulations will be presented to evaluate the model's characteristics.

Effectiveness of commercial bioactivator in biofilters on acclimatization time and reduction of BOD and COD in cracker industrial wastewater treatment

Abstract Indramayu is one of the regions with a fish cracker processing industry with production output of 3.5 thousand tons or 45.20% of the total production of processed fishery products. The production of fish crackers produces wastewater which increase organic pollutants in wates that exceed quality standards. The study aims to determine the effectiveness of commercial bioactivator on acclimatization time and the reduction of COD and BOD levels in liquid waste of the cracker industry by using anaerobic-aerobic biofilters on andesite stone fragment media. Based on the results of this study, the bioactivator was able to reduce COD concentration from 2337.71 mg/L to 196.94 mg/L and BOD concentration from 653.6 mg/L to 95.09 mg/L. The final ratio of BOD/COD increased from 0.22 at 4 hours to 0.47 at 24 hours indicating a shift into the biodegradable zone. The total COD removal efficiency reached 91.42%, while BOD removal efficiency reached 85.26%.

Hydrogen-rich gas generation from enhanced catalytic cracking of biomass tar and related model compounds on Ni-Fe/ASA@HZSM-5 catalyst: Pathways and mechanisms

This study focused on the design of complex tar model compounds (CTMC) and synthesized a highly efficient aluminum dross (ASA) combined with HZSM-5 molecular sieve co-loaded bimetallic Ni-Fe catalyst (Ni-Fe/ASA@HZSM-5), comprehensively evaluated the catalytic cracking of real tar and its model compound by adjusting the injection amount and injection state of tar, and catalyst types to obtain hydrogen-rich gas with high H2 and low CO2 content. The results showed under the conditions of the injection amount of 0.6 mL/min, pyrolysis temperature of 600 °C, reforming temperature of 800 °C in the liquid phase, Ni-Fe/ASA@HZSM-5 displays excellent catalytic cracking performance with CTMC conversion efficiency of 87.80 % (79.46 % of gas yield and 34.20 vol% of H2 yield). The possible cracking paths between different components of CTMC in the Ni-Fe catalytic system were summarized by the experimental data and product distribution, the catalytic mechanism of Ni–Fe based catalysts can be attributed to the formation of a Ni-Fe alloy and the synergistic effect of ASA and HZSM-5 co-carrier. Further, the catalytic cracking pathway of CTMC was enhanced in the gas phase, the higher CTMC conversion efficiency of 93.68 %, gas yield (a mass fraction of 82.51 %) and H2 (a volume fraction of 33.59 %) were obtained from catalytic cracking of CTMC, the liquid yield decreased by 12.39 %, significantly improved the cracking degree and gas production capacity of CTMC. The real tar showed the same catalytic pyrolysis path and product distribution. Under the same cracking conditions, the yields of gas, liquid and char were 84.85 %, 12.00 % and 3.15 % respectively, and obtained the hydrogen yield of 55.29 mL/g. The CTMC simplifies the cracking process and reduces polymerization, provides insights into the cracking mechanisms of heavy components in biomass tar. Furthermore, the synergy of Ni and Fe contributed to greater activity for CTMC and real tar cracking, ASA combined with HZSM-5 molecular sieve co-loaded bimetallic Ni-Fe catalysts have a promising application potential as highly efficient catalysts for tar removal and reutilization.

Optimization and Control of a Stabilization Column for a Propylene-Producing Fluid Catalytic Cracking Process

Optimization and Control of a Stabilization Column for a Propylene-Producing Fluid Catalytic Cracking Process

Application of multifractal spectrum to characterize the evolution of multiple cracks in concrete beams

The quantitative characterization of concrete multiple cracks in fractal dimension is limited to the holistic macroscopic characterization of a particular damage state only, and fails to portray the local subtle variations of the cracks. Based on this, multifractal theory is introduced to quantitatively characterize the evolution process of concrete beam multiple cracks and to deeply analyze the relationship between the spectrum parameters and the typical mechanical parameters of concrete beams. Firstly, the simulation of the crack evolution process in concrete beams is executed precisely utilizing the nonlinear finite element software ATENA to enhance the dataset of multifractal analysis at each load step. Secondly, an enhanced C-J algorithm program for the multifractal spectrum is developed to determine the reasonable range of multifractal spectrum parameters and quantitatively characterize the multiple crack evolution of concrete beams at each loading step. Then the evolutionary characteristics and damage patterns of multiple cracks under varying reinforcement ratios and shear span ratios is elucidated. Additionally, the research probes into the relationships between the multifractal spectrum and the mechanical and damage parameters. The results demonstrate that higher reinforcement ratios in components lead to reduced crack extension and lower crack complexity, resulting in a generally decreasing trend for FD, as the reinforcement ratio increases by 0.957 %, the FD decreases by 0.76 %. Larger shear span ratios enhancing crack inhomogeneity and causing a gradual increase in both FD and Δa, as the shear span ratios decreases by 41.67 %, the FD decreases by 1.35 %. The drift of the multifractal spectrum and the variation of the multifractal spectrum parameters portray the evolution of the overall and local fine cracks in concrete beams. The multifractal spectrum can reflect the damage state of components in a more comprehensive and detailed way, which provides a new way for the damage warning and evaluation of concrete structures.

Tensile Fracture Initiation and Propagation of Granite and Gneiss at Wedge Splitting Tests: Part 2—Fracturing Studies Based on Digital Image Correlation and Thin Section Analysis

AbstractThe crack development in quasi-brittle granite and brittle gneiss under mode I loading condition was monitored using digital image correlation (DIC) technique during wedge splitting tests. The cracking behavior was studied on granite specimens that were split in one material direction, perpendicular to the rift plane, and gneiss specimens that were split in three different material directions, parallel and perpendicular to the foliation (along and across a lineation). The granite specimens had a saw cut 5 mm-wide notch and a blunt round notch in form of a 32 mm borehole. The gneiss specimens had a saw cut notch. The results from the DIC measurements revealed a meandering and branching crack path for the granite, whereas a smoother crack path for the gneiss with almost no branching. This behavior was confirmed by microscopy images from thin sections taken from specimens after testing. The thin sections showed that the fractures were prone to propagate across grains in the more coarse-grained granite than in the fine-grained gneiss, where the fractures propagated almost entirely along grain boundaries. The crack initiation occurred mainly in the corner of the saw cut notches and centrally in the round notch. However, the initiation locations in the granite were affected by the medium- to coarse-grained microstructure with grains preventing initiation and propagation which yielded displaced positions out from the ideal ones with respect to the highest stress in some cases. The crack opening displacement was determined along the crack path from the DIC measurements at 12 stages on each specimen of the advancing crack during the splitting progress. The critical crack opening displacement and length of the fracture process zone were assessed and the crack front position yielding the crack length along the tests was determined. The results showed a critical crack length when the deformations in the ligament (also called plastic hinge) affected the cracking process. The average crack velocity in gneiss during the test was more than twice as high as in the granite. This is attributed to a combined effect of the higher brittleness in the gneiss and the effect of a too large elastic energy in the specimen and test setup in relation to the dissipated fracture energy which made the initial crack propagation in the gneiss specimens nearly unstable. The strain energy release rate was calculated along the crack propagation and showed a lower value when the crack lengths were less than 40–60 mm. The calculation of the strain energy release rate was made on crack length measurements from DIC results. The results from the investigation were discussed in relation to the few other similar results found in the literature. The findings give an insight and understanding of the cracking process via both qualitative and quantitative results. Several used methods were novel or not used together in a single study as in this one.

Cell Design and Optimization for Efficient Hydrogen Production through Ammonia Electrolysis

Hydrogen, pivotal for a carbon-neutral energy framework, faces hurdles in storage and transport, leading to the consideration of ammonia as a viable hydrogen carrier. Compared to hydrogen, ammonia can be liquefied at moderate temperatures and has higher energy volumetric density. Despite ammonia's potential, presently an energy-intense thermal cracking process is necessary to convert it back to hydrogen. This prompted us to explore ammonia electrolysis as a less energy intense, more sustainable alternative for ammonia-to-hydrogen process. This method promises lower theoretical energy consumption and could in principle be driven by renewable energy sources. The number of research efforts focusing on ammonia electrolysis (ammonia electro-oxidation) is limited and most frequently focuses on catalyst development to minimize poisoning and overpotentials. Studies pursuing electrolysis cell designs for ammonia oxidation are even scarcer. Our study delves into design strategies for an ammonia electrolyzer, pairing ammonia oxidation with hydrogen evolution, aiming to optimize the entire process to enhance the prospects of ammonia as a hydrogen carrier.This presentation will compare three different designs for ammonia electrolysis: batch, flow, and membrane electrolyte assembly (MEA) cell configurations. Each cell is characterized with respect to durability and product selectivity. Ultimately, we studied multiple factors, including flow rate, ammonia concentration, pH, and different operation protocols for MEA cells. The results provide guidance toward optimal cell design and operational protocols for a high-performing ammonia electrolyzer.

Effect of amygdala on the pore-crack structure and mechanical properties of Permian tuff and breccia during hydration

The Permian volcanic rocks in the Sichuan Basin are rich in oil and gas resources. However, during volcanic rock exploitation, the working fluid fully contacts with the volcanic rocks, and hydration reaction will occur, which destroys the pore structure of the rock, makes the rock layer loose and fragile, increases the risk of wellbore collapse, and causes the loss of volcanic rock production. However, the reasons for the change of pore structure of volcanic rocks after hydration and the understanding of the hydration mechanism of volcanic rocks are not clear. Therefore, this paper uses microscopic and mechanical experimental testing methods combined with digital core technology to study the changes of pore-crack structure, amygdale structure and mechanical characteristics of Permian tuff and breccia in Sichuan Basin before and after hydration. The research results show that during the hydration process of volcanic rocks, pores, cracks, and amygdales are transformed into each other. The hydration process of the volcanic rocks is characterized by the disappearance of isolated pores, the generation of small cracks, and the generation and transformation of new pores into amygdales. Amygdales also have an important impact on the mechanical properties and hydration of volcanic rocks. When the content of amygdales in volcanic rocks is high, the rocks are more prone to breakage. In addition, amygdales promote the hydration reaction of volcanic rocks, and the size and number of amygdales determine the strength of volcanic rock hydration ability. When the content of amygdales in the rock is higher, the rock is more prone to hydration reactions. Therefore, in the process of gas reservoir development, understanding the distribution and characteristics of amygdale is helpful to optimize the composition of the working fluid and enhance drilling technology. It aims to maximize the productivity gas wells.

Determination of the Optimum Moisture Content for the Whole Kernel Recovery During the Cracking Process of Oil Palm Nuts

This study aimed to investigate the effect of moisture content on palm nut cracking and kernel production using a locally fabricated palm nut cracker. Palm nuts of mixed varieties (Dura, Tenera, and Pisifera) were manually cleaned and dried at different moisture content levels ranging from 8.53% to 26.82%. The palm nut cracker is designed with four major units: the in-feed unit, cracking unit, discharge unit and the driving unit. The cracking efficiency was determined by calculating the ratio of completely cracked nuts to the total nuts fed into the hopper. Results show that the whole kernel recovery varies considerably with moisture content and cracking speed. At the lowest moisture content of 8.58%, the whole kernel recovery is generally low across all the cracking speeds. As the moisture content increases, there is a significant improvement in whole kernel recovery at all the cracking speeds. The highest whole kernel recovery was obtained at intermediate moisture contents of around 14% to 18%, and the cracking speeds of 1000 rpm to 1400 rpm. The ANOVA table shows that both the cracking speed and moisture content have a significant effect on whole kernel recovery. Optimizing these parameters could lead to higher whole kernel recovery. However, it is important to note that other factors such as the cultivar of the nut and the equipment used may also affect the whole kernel recovery.

Integrated Hybrid Modelling and Surrogate Model-Based Operation Optimization of Fluid Catalytic Cracking Process

Fluid Catalytic Cracking (FCC) is one of the most important conversion processes in oil refineries, widely used to convert high-boiling, high-molecular-weight hydrocarbon components from crude oil into more valuable products like gasoline and diesel. Advanced simulation and optimization technologies are critical for improving the operational efficiency and economic performance of the FCC process. First-principles-based simulators rely on parameter estimation and are computationally intensive, making them unsuitable for online optimization. In recent years, with the development of deep learning, data-driven models have made significant progress in FCC modeling. However, due to their black-box nature and difficulty with extrapolation, they are rarely used for optimization. To bridge this gap, we propose an integrated framework that combines hybrid modeling and surrogate model-based optimization. This approach combines plant and simulation data to train a multi-task learning prediction model, which then serves as a surrogate for operational optimization. Validated on a large-scale FCC unit in southern China, the model predicts product yields with an error margin of under 4.84% for all products. Following optimization, yields of LNG, gasoline, and diesel rose by an average of 0.10 wt%, 1.58 wt%, and 1.05 wt%, respectively, resulting in a 3.67% increase in product revenues. This highlights the substantial potential of this framework for industrial applications.

Multiscale modeling of thermo-hydromechanical behavior of clayey rocks and application to geological disposal of radioactive waste

This work is devoted to numerical analysis of thermo-hydromechanical problem and cracking process in saturated porous media in the context of deep geological disposal of radioactive waste. The fundamental background of thermo-poro-elastoplasticity theory is first summarized. The emphasis is put on the effect of pore fluid pressure on plastic deformation. A micromechanics-based elastoplastic model is then presented for a class of clayey rocks considered as host rock. Based on linear and nonlinear homogenization techniques, the proposed model is able to systematically account for the influences of porosity and mineral composition on macroscopic elastic properties and plastic yield strength. The initial anisotropy and time-dependent deformation are also taken into account. The induced cracking process is described by using a non-local damage model. A specific hybrid formulation is proposed, able to conveniently capture tensile, shear and mixed cracks. In particular, the influences of pore pressure and confining stress on the shear cracking mechanism are taken into account. The proposed model is applied to investigating thermo-hydromechanical responses and induced damage evolution in laboratory tests at the sample scale. In the last part, an in-situ heating experiment is analyzed by using the proposed model. Numerical results are compared with experimental data and field measurements in terms of temperature variation, pore fluid pressure change and induced damaged zone.

Catalytic Cracking of Liquefied Petroleum Gas (LPG) to Light Olefins Using Zeolite-Based Materials: Recent Advances, Trends, Challenges and Future Perspectives.

The catalytic cracking of liquefied petroleum gas (LPG) has attracted significant attention due to its importance in producing valuable feedstocks for the petrochemical industry. This review provides an overview of recent developments in zeolite-based catalyst technology for converting LPG into light olefins. Catalytic cracking utilizes zeolite-based catalysts usually associated with stability challenges, such as coking and sintering. The discussion focused on the underlying mechanisms that govern the catalytic cracking process and provided insights into the complex reaction pathways involved. A comprehensive analysis of various strategies employed for improving the effectiveness of zeolite catalysts has been discussed in this review. These strategies encompass using transition metals to modify catalyst properties, treatments involving phosphorous modification, alkaline earth metals, and alkali metals to alter the acidity level of the zeolites. The elucidation of the impact of silica-to-alumina ratios in zeolites and the development of hierarchical zeolite-based catalysts through top-down and bottom-up methodologies are also discussed.