Reactor Unit Research Articles

The effect of temperature on the Emission Factor of air emissions from pyrolysis of used tyres

Used tyres pyrolysis is an efficient solid waste management strategy for used tyres and a growing method of fuel oil production. However, the impact of air emissions associated at different temperature on ambient air quality has not been determined. To solve this problem, a pyrolysis fixed bed reactor and a condensing unit for separating liquid from produced gas were designed and constructed. 0.20 kg of used tyres were pyrolysed in the reactor and air emissions from the reactor chamber was characterized for air pollutants using the E-instrument E8500. Using a combination of measured mass of pollutants, mass of tyre pyrolzed and time taken during pyrolysis, Emission Factors of the air pollutants were established from the study at 200 °C, 300 °C and 400 °C. The concentration measured between 200 °C - 400 °C were in the range of 15 -7497 mg/m3, 0 – 4680 mg/m3, 38.25 – 103, 277.76 mg/m3 and 2 – 293 mg/m3 for CO, NOx, HC and H2S respectively. The developed emission factors were in the range of 16.52 – 8370.04 g kg-1, 0 – 4470.26 g kg-1, 42.126 – 104,055.9 g kg-1 and 2.20 – 322.69 g kg-1. The designed and constructed pyrolysis reactor and condenser unit were effective for used tyre pyrolysis while the measured air pollutants concentration were higher for all pollutants except H2S using the Federal Ministry of Environment (FEPA, 1991) standard. Hence, it is necessary to carry out further studies on air pollution control from waste tyre pyrolysis at lower temperature.

Sustainable and Advanced LED-Implanted Microfluidic Photoreactor with Coupled Optical Fiber Enabling Efficient Photocatalytic Synthesis Beside Online Reaction Progress Monitoring.

The conventional methods for the photoinduced synthesis of benzimidazoles may need further improvement regarding a safer and energy-efficient synthesis platform with in-process monitoring for maximum yield within a much reduced reaction time. This work describes the use of a novel optofluidic Lab-on-a-Chip technology for safer, energy-efficient, and expedited synthesis of benzimidazole derivatives in excellent yields along with real-time quantitative measurement during product formation. This innovative method involves synthesis within LED-embedded microfluidic reactors, allowing for rapid synthesis of benzimidazole derivatives via photoinduced condensation cyclization reactions of aryl aldehydes and o-phenylenediamines using a Rose Bengal/fluorescein photocatalyst. It results in good to excellent yields (85-94%) in a notably shorter period of time (10 min) as compared to that for the batch protocol reaction (2-3 h). The incorporation of a reaction-monitoring microfluidic device precisely connected to the microfluidic reactor (microreactor) unit successfully avoids interference from light sources, ensuring consistent UV-vis spectroscopic observations of the produced benzimidazole derivatives. This LED-embedded microfluidic device's capability of photoinduced synthesis, along with real-time spectroscopic analysis, represents a promising breakthrough in organic synthesis. The proposed approach minimizes the potential for accidents, prevents waste of chemicals, maximizes atom economy, and designs an energy-efficient synthesis route, along with real-time in-process monitoring.

Reducing sludge formation by enhancing biological decay of biomass: a mathematical model

Abstract We investigate a model for an activated sludge process that contains a chemical reactor unit attached to a bioreactor. Inside the chemical reactor unit, a process takes place which increases the decay coefficient of heterotrophic biomass. This mimics a number of experimental techniques which are used to decrease the mass of sludge. Such techniques are of growing interest as the activated sludge process produces large volumes of sludge; the costs associated with its disposal are significant. Our primary interest is to investigate how the operation of the chemical reactor unit changes the steady-state concentrations of both the total suspended solids within the biological reactor and the chemical oxygen demand in the effluent stream. The operation of a chemical reactor unit always increases the value of chemical oxygen demand in the effluent stream. The behaviour of the total suspended solids is more complicated; in some cases, the operation of the CRU increases the total suspended solids. For a fixed value of the chemical oxygen demand in the influent stream, we show that both the percentage reduction in the total suspended solids and the chemical oxygen demand in the effluent stream are increasing functions of the soluble substrate in the feed. The same trends occur when the influent composition is fixed, and the disintegration rate inside the chemical reactor unit is increased. This leads to dichotomic behaviour, decreasing the total suspended solids increases the chemical oxygen demand in the effluent stream. There are two consequences of this behaviour. Firstly, there are some waste streams that can not be cleaned using the process configuration considered in this paper. Secondly, the imposition of a target value for the chemical oxygen demand in the effluent stream imposes a maximum achievable reduction in the total suspended solids in the biological reactor. Higher reductions can not be achieved without causing the chemical oxygen demand in the effluent stream to exceed the target value.

Optimization of Lipid-Based Nanoparticles Formulation Loaded with Biological Product Using A Novel Design Vortex Tube Reactor via Flow Chemistry.

Lipid-based nanoparticles (LNPs) is increasingly recognized for their potential in drug delivery, offering protection to hydrophobic drugs from degradation. Industrial synthesis of LNPs, exemplified by Pfizer-BioNTech and Moderna mRNA vaccines, utilizes flow chemistry or microfluidics, showcasing its scalability. This study explores the utilization of a novel design reactor, the vortex tube reactor, within flow chemistry for LNPs synthesis, aiming to optimize its conditions and compare them with batch synthesis. LNPs were synthesized using the vortex tube reactor, incorporating bovine serum albumin (BSA) as a model drug in the aqueous phase, alongside 1.2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and cholesterol in the organic phase. Design of experiments (DoE), specifically Box-Behnken design, was employed to optimize parameters, including X1: the flow rate ratio (10-100 mL/min), X2: the aqueous-to-organic volumetric ratio (1:1-10:1), and X3: the number of reactor units (1-5 units). Responses evaluated encompassed physical properties and productivity. Optimized conditions were determined by minimizing particle size (Y1), polydispersity index (Y2), and zeta potential (Y3), while maximizing entrapment efficiency (Y4), drug loading (Y5), and productivity (Y5). Results indicated that optimal conditions were achieved at X1 of 100 mL/min, X2 of 5.278, and X3 of 1 unit. LNPs synthesized under these conditions exhibited favorable physical properties and productivity, with uniformity maintained across batches. The vortex tube reactor demonstrated superiority over batch synthesis, yielding smaller particles (166.23 ± 0.98 nm), more uniform nanoparticles (PDI 0.17 ± 0.01), and higher entrapment (67.75 ± 1.55%) and loading capacities (36.39 ± 0.83%), indicative of enhanced productivity (313.4 ± 12.88 mg/min). This study elucidates the potential of flow chemistry, particularly utilizing the vortex tube reactor, for large-scale LNPs formulation, offering insights into parameter relationships and advancing nanoparticle synthesis for drug delivery applications.

Physics-informed neural networks with hard linear equality constraints

Surrogate modeling is used to replace computationally expensive simulations. Neural networks have been widely applied as surrogate models that enable efficient evaluations over complex physical systems. Despite this, neural networks are data-driven models and devoid of any physics. The incorporation of physics into neural networks can improve generalization and data efficiency. The physics-informed neural network (PINN) is an approach to leverage known physical constraints present in the data, but it cannot strictly satisfy them in the predictions. This work proposes a novel physics-informed neural network, KKT-hPINN, which rigorously guarantees hard linear equality constraints through projection layers derived from KKT conditions. Numerical experiments on Aspen models of a continuous stirred-tank reactor (CSTR) unit, an extractive distillation subsystem, and a chemical plant demonstrate that this model can further enhance the prediction accuracy.

Hydrogen Production using PEM Electrolyzer

Abstract: This paper presents a simulation study of alkaline electrolysis for H2 production using Aspen Plus. The simulation model incorporates reactor, separators, mixer, and heat exchanger units to accurately represent the AWE process. The model is designed to evaluate the performance of an AWE system under different operating conditions and aims to achieve a reference H2 production rate of 0.179663 kg/hr. The simulation results demonstrate that the AWE system can successfully produce H2 at the specified rate. The model provides a detailed analysis of the system's behavior and H2 production rate, under varying operating conditions. The findings of this study provide valuable insights into optimizing the design and operation of AWE systems for large-scale H2 production

Industrial Scale Reactor Design for Al2O3 Production from Bauxite and Sodium Hydroxide Solution

The aim of this study is to design a reactor that can optimize the production of Al2O3 from the reaction between bauxite and sodium hydroxide solution on an industrial scale. The type of reactor used for the production of Al2O3 nanoparticles is a Continuous Flow Stirred – Tank Reactor (CSTR). The method used in this study is to perform computational analysis and calculation of the dimensions of the reactor and stirrer as well as the mass balance, using basic calculation with Microsoft Excel application. To produce Al2O3 nanoparticles on an industrial scale, three reactor units and three stirrers are required. Based on the calculation results, it is found that the first and second reactors have volume 2,9689 m3 with height 5,0424 ft and require a stirrer with six blades with an angle of 45owhich has power 50 Hp. The third reactor has volume 4,3387 m3 with height 9,0847 ft and requires one stirrer with six blades with an angle of 45o which has a power 75 Hp. The computational calculation results in this study can be used as an overview in designing a reactor to produce Al2O3nanoparticles from bauxite and sodium hydroxide solution on an industrial scale

Process intensification in flow chemistry using micro and millidevices: Numerical simulations of the syntheses of three different intermediate API compounds for diabetes mellitus drug production

Microreactor Technology (MRT) appears as an interesting alternative for process intensification, including the development of continuous synthesis of fine chemicals and Active Pharmaceutical Ingredients (API). The inherent proposal of MRT is to reduce the scale-up time by simply increasing the number of microreactors in parallel, the numbering-up concept using optimal designed micro or millidevices. Among the API, rosiglitazone and lobeglitazone are derivatives of thiazolidine-2,4-dione (TZD), which is used as a building block, for molecules with biological activity, sensitive to insulin and, thus, with its administration the body makes better use of the insulin it produces, being an important structural element in medicinal chemistry, especially for type 2 diabetes mellitus, one of the biggest concerns in the health area worldwide, affecting nowadays more than 180 million people. The numerical assessment of MRT for various API synthesis related to type 2 diabetes mellitus drugs indicates its comparable or superior performance compared to traditional batch process. Specifically, proposed micromixer designs facilitate successful scale-up to milliscale while maintaining microscale performance, with significantly lower pressure drops than commercial Asia microreactors. The proposed flow distributors offer good performance in ensuring uniform distribution across outlets due to their conical shape design and laminar flow regime, with low pressure drops. The flow distributor with eights outlet is preferred for higher flow rates due to its superior performance, minimizing the pressure drops. Efficient flow rate and molar concentration control at each reactor unit can be ensured by using one distributor for each reactant's feed stream. This approach guarantees accurate concentration, flow rate control and ideal residence time, ultimately facilitating higher total throughput for scale-up. The potential use of micromixer actuators lies in its ability to maintain or enhance performance while transitioning from micro to milli-scale, offering promising alternatives for process intensification and scale-up in pharmaceutical synthesis, particularly for medications targeting type 2 diabetes mellitus.

Features of the architecture of nuclear power plants

The article analyses the peculiarities of the specific industrial landscape of nuclear power plants on the basis of domestic and foreign experience and highlights the importance of adapting these industrial complexes with a heavy technological regime to modern architectural post-industrial requirements. The architecture of nuclear power plants (hereinafter referred to as NPPs) is often a subject of debate. Some people believe that NPPs are a symbol of technological progress and should be presented as monumental structures. Others believe that NPPs are potentially dangerous facilities and should be built in a more modest style. Most industrial facilities, such as NPPs, were built in the industrial era and do not meet the requirements of the post-industrial era in terms of environmental friendliness, adaptability and architectural coherence. This is due to the duration of their construction and the environment in which they are located. Therefore, they need to be modernised. Analysing the architectural features of nuclear power plants, the author has determined that, regardless of the architectural style, NPPs usually have several common features, namely: large, monumental buildings that emphasise their importance, features that reflect their technological nature, such as cooling towers and reactor units. Due to the regional location, NPPs have their own peculiarities in composition and architectural decoration, which can not only modernise the appearance, but also depict elements of national identification. Due to their location on the ground, in a certain established natural environment, NPPs require a large amount of water resources due to the peculiarities of the heavy technological regime (reactor type) that takes place at the enterprise, so they are located on the ground near water bodies and reservoirs, and sometimes absorb entire rivers and lakes for the needs of technological processes. The mountainous terrain factor is equally important. It affects the architectural landscape of NPPs and their authenticity. Equally important is the period in which the plant was designed and built, as nuclear power is an important economic and political component of the country where it is produced. In terms of form, space and volume solutions, typology, and architectural and planning principles, it is possible to draw an analogy with the stage of development of a state.

Simulation of Olive Pomace Gasification for Hydrogen Production Using Aspen Plus: Case Study Lebanon

Biomass is a renewable energy source gaining attention for its potential to replace fossil fuels. Biomass gasification can produce hydrogen-rich gas, offering an environmentally friendly fuel for power generation, transportation, and industry. Hydrogen is a promising energy carrier due to its high energy density, low greenhouse gas emissions, and versatility. This study aims to develop a hydrogen generation plant using a dual fluidized bed gasifier, which employs steam as a gasifying agent, to convert olive pomace waste from the Lebanese olive oil industry into hydrogen. The process is simulated using Aspen Plus and Fortran coding, and it includes a drying unit, gasification unit, gas cleaning unit, steam methane reformer unit, water–gas shift reactor unit, and a pressure swing adsorption unit. The generated gas composition is verified against previous research. Sensitivity analyses are conducted to investigate the impacts of the steam-to-biomass ratio (STBR) and gasification temperature on gas composition, demonstrating a valid STBR range of 0.5 to 1 and a reasonable gasification temperature range of 700 °C to 800 °C. Further sensitivity analyses assess the impact of reformer temperature and the steam-to-carbon ratio (S/C) on the gas composition leaving the steam methane reformer.

An apparatus to measure thermal conductivity of ceramic pebble beds under uniaxial compressive stress

Pebble beds have various applications in many industrial and research sectors. Lithium ceramic pebble beds have specific application in fusion reactors as one of the most promising candidates for tritium breeding material. During the operation of the fusion reactor, these pebble beds will have to sustain various thermal and mechanical stresses. Therefore, it is necessary to do thermal characterisation of these pebble beds under different stress conditions and generate sufficient data on their thermal properties, which is essential for designing breeder units of fusion reactors. In this work, an apparatus has been designed to evaluate the thermal conductivity of ceramic pebble beds under compressive stress. It can be mounted to any standard universal testing machine with the necessary adjustments. The apparatus is based on the transient hot-wire method, widely used to evaluate the thermal conductivity of porous materials. A platinum wire with a diameter of 0.5 mm was used as a hot-wire. Instead of utilising a thermocouple, the 4-wire approach was used to obtain the temperature. The transient temperature response of the hot-wire was obtained by applying a 7A constant current to it and monitoring the voltage drop along its 40 mm length. The thermal conductivity of the water gel was measured to assess the accuracy of the apparatus; the results showed a less than 1.5 % variation from the reference value. In this study, the thermal conductivity of Li2TiO3 pebbles was measured in an air and helium environment in different stress conditions. In an air environment, measurements were done at atmospheric pressure, whereas in a helium gas environment, they were performed at gauge pressures of 0.05 bar, 0.5 bar, and 1 bar. The measurements were conducted in two scenarios: (i) constant stress condition at 0, 3, and 6 MPa, and (ii) Cyclic loading-unloading of 0.037–3 MPa and 0.037–6 MPa. It was found that the pebble bed's thermal conductivity rose in tandem with increased compressive stress in both the helium and air environments. Pebble bed’s thermal conductivity was found to be higher in a helium gas environment than in air. The thermal conductivity of the pebble bed increased slightly with rising helium gas gauge pressure from 0.05 bar to 1 bar. This work provides a design to incorporate 4-wire temperature measurement in the hot-wire method for thermal conductivity measurement of compressed pebble beds. It also contributes to the thermal conductivity data of Li2TiO3 pebbles in cyclic stress conditions in helium and air environments.

Selected Legal and Safety Aspects of the “Coal-To-Nuclear” Strategy in Poland

Poland is actively exploring the application of nuclear power as a substitute for its present reliance on fossil fuels for the generation of heat and electricity. This change reflects a calculated attempt to reduce carbon emissions, diversify the nation’s energy sources, and enhance the sustainability of its energy infrastructure. However, the implementation of nuclear technology faces many challenges, such as radiation exposure, the production of radioactive waste, the off-site effects of nuclear accidents, and high capital costs. Addressing such nuclear-safety-related issues is crucial for nuclear technology’s successful deployment. An extended analysis of the “coal-to-nuclear” process in terms of its safety has to be performed. Therefore, this review paper covers multidisciplinary studies related to the rollout of nuclear energy in Poland. The first stage of this study was the identification of the key areas of analysis, which included (i) formal requirements and recommendations imposed by international and national organizations on the process of designing and operating nuclear power systems; (ii) potential nuclear hazards for the personnel working at a nuclear reactor unit and the local population; (iii) the applied solutions of the security systems of a reactor itself, the steam turbine cycle, and the auxiliary infrastructure; and (iv) the management of spent nuclear fuel and radioactive waste. This methodology, developed based on a review of the literature and international standards, was tested for the selected country—Poland.

Synthesis of L-Lactide from Lactic Acid and Production of PLA Pellets: Full-Cycle Laboratory-Scale Technology.

Lactide is one of the most popular and promising monomers for the synthesis of biocompatible and biodegradable polylactide and its copolymers. The goal of this work was to carry out a full cycle of polylactide production from lactic acid. Process conditions and ratios of reagents were optimized, and the key properties of the synthesized polymers were investigated. The influence of synthesis conditions and the molecular weight of lactic acid oligomers on the yield of lactide was studied. Lactide polymerization was first carried out in a 500 mL flask and then scaled up and carried out in a 2000 mL laboratory reactor setup with a combined extruder. Initially, the lactic acid solution was concentrated to remove free water; then, the oligomerization and synthesis of lactide were carried out in one flask in the presence of various concentrations of tin octoate catalyst at temperatures from 150 to 210 °C. The yield of lactide was 67-69%. The resulting raw lactide was purified by recrystallization in solvents. The yield of lactide after recrystallization in butyl acetate (selected as the optimal solvent for laboratory purification) was 41.4%. Further, the polymerization of lactide was carried out in a reactor unit at a tin octoate catalyst concentration of 500 ppm. Conversion was 95%; Mw = 228 kDa; and PDI = 1.94. The resulting products were studied by differential scanning calorimetry, NMR spectroscopy and gel permeation chromatography. The resulting polylactide in the form of pellets was obtained using an extruder and a pelletizer.

Evaluation of derived concentration guideline levels reflecting the site-specific data for the soil of the Korea research reactor unit 1 and 2

The purpose of this study is to evaluate the derived concentration guideline levels for unrestricted site reuse the Korea research reactor unit 1 and 2. Distribution coefficients for Co-60 and Sr-90 were derived, and site-specific values of the KRR soil were applied for the DCGLs for the seven target nuclide. The distribution coefficients of Co-60 and Sr-90 were 6,128 and 86.0 mL/g. The DCGLs derived from the dose by age group were 0.053 Bq/g for Co-60 and 45.0 Bq/g for H-3.

Proposal and simulation of a geothermal-driven water electrolysis unit integrated with a CO2 methanation process toward a novel sustainable framework

This paper presents a novel multigeneration structure powered by geothermal energy, featuring a geothermal power plant, water electrolyzer unit, methanation reactor, fuel and utility production unit, supercritical-carbon dioxide cycle, and both high-temperature and low-temperature organic Rankine cycles. Simulated in Aspen HYSYS software and analyzed from energy, exergy, economic, and environmental (4E) perspectives, the process, under base operating conditions, is capable of producing 20,940 kW of power, 620.70 kg/h of hydrogen, 4,913 kg/h of oxygen, 12.35 kg/s of domestic hot water, 5.293 kg/s of chilled water, and 2.659 kg/s of carbon dioxide with over 99% mole purity. Efficiency assessments reveal energy, exergy, and electrical efficiencies of 10.69%, 48.53%, and 3.73%, respectively, with a total unit product cost of $3.11/GJ and a net present value of $67.40 million. The water electrolyzer unit, with an 88.94% exergy efficiency and a 10% contribution to total system irreversibility, is identified as the most efficient subsystem. The geothermal power plant accounts for the highest system irreversibility at 61%, while the combustor in the fuel and utility production unit contributes 11,250 kW of irreversibility. Environmentally, the system operates with zero emissions and significantly reduces annual CO2 emissions compared to coal, oil, biomass, and natural gas power plants by 453.14 × 106, 576.80 × 106, 111.92 × 106, and 344.10 × 106 kg, respectively.

Assessment of soil density and distribution coefficient of Cs-137 for deriving DCGLs in korea research reactor unit 1 and 2

To obtain site-specific values of the Derived Concentration Guideline Levels (DCGLs) for decommissioning of KRR-1&2, the soil density and distribution coefficient values for Cs-137, a major contaminant radionuclide, were determined. The soil density was evaluated according to the test method established by the Korean Agency for Technology and Standards of the Ministry of Trade, Industry, and Energy (KATS). The distribution coefficient was evaluated using a batch test. The validity of using the evaluated soil density and distribution coefficient as site-specific values was assessed through radiation dose assessment reflecting these values. Average soil density value obtained was 1.738 g/cm3, which was within the typical range of normal soil density, 1.0–1.8 g/cm3. The average distribution coefficient value was 7,754 mL/g. Applying the maximum, average, and minimum values of the evaluated soil density and distribution coefficient showed similar radiation dose results, thus suggesting that it is reasonable to use the average values of each parameter as site-specific values. Findings of this study can help determine DCGLs that reflect the characteristics of the research reactor site.

Comprehensive two-dimensional liquid chromatography with high resolution mass spectrometry to investigate the photoelectrochemical degradation of environmentally relevant pharmaceuticals and their degradation products in water

The widespread presence of organic micropollutants in the environment reflects the inability of traditional wastewater treatment plants to remove them. In this context, advanced oxidation processes (AOPs) have emerged as promising quaternary wastewater treatment technologies since they efficiently degrade recalcitrant components by generating highly reactive free radicals. Nonetheless, the chemical characterization of potentially harmful byproducts is essential to avoid the contamination of natural water bodies with hazardous substances. Given the complexity of wastewater matrices, the implementation of comprehensive analytical methodologies is required. In this work, the simultaneous photoelectrochemical degradation of seven environmentally relevant pharmaceuticals and one metabolite from the EU Watch List 2020/1161 was examined in ultrapure water and simulated wastewater, achieving excellent removal efficiencies (overall >95%) after 180 min treatment. The reactor unit was linked to an online LC sample manager, allowing for automated sampling every 15 min and near real-time process monitoring. Online comprehensive two-dimensional liquid chromatography (LC × LC) coupled with high resolution mass spectrometry (HRMS) was subsequently used to tentatively identify degradation products after photoelectrochemical degradation. Two reversed-phase liquid chromatography (RPLC) columns were used: an SB-C18 column operated with 5 mM ammonium formate at pH 5.8 (1A) and methanol (1B) as the mobile phases in the first dimension and an SB-Aq column using acidified water at pH 3.1 (2A) and acetonitrile (2B) as the mobile phases in the second dimension. This resulted in a five-fold increase in peak capacity compared to one-dimensional LC while maintaining the same total analysis time of 50 min. The LC x LC method allowed the tentative identification of 12 venlafaxine, 7 trimethoprim and 10 ciprofloxacin intermediates. Subsequent toxicity predictions suggested that some of these byproducts were potentially harmful.This study presents an effective hybrid technology for the simultaneous removal of pharmaceuticals from contaminated wastewater matrices and demonstrates how multidimensional liquid chromatography techniques can be applied to better understand the degradation mechanisms after the treatment of micropollutants with AOPs.

Pengolahan Limbah Domestik PT X Dengan Unit Anaerobic Buffle Reaktor

Domestic waste produced by one of the chicken cutting industries, PT X, in the Jombang region, East Java, has not been properly treated. Domestic waste, commonly known as greywater, is wastewater originating from kitchen activities, toilets, sinks, and so on, carried out by the workers. If this wastewater is directly discharged into the environment without prior treatment, it can cause pollution and have adverse effects on aquatic life. One of the efforts to manage PT X's domestic waste is by using the Anaerobic Baffle Reactor (ABR) unit. The selection of the ABR unit is based on the treatment system at PT X's wastewater treatment plant (IPAL). In this IPAL, there is a sedimentation process and degradation of organic material by anaerobic bacteria, which can minimize the land use for domestic wastewater treatment. The aim of this research is to determine the efficiency in reducing parameters present in PT X's domestic wastewater, namely COD, BOD, and TSS. This study is expected to provide an alternative for treating domestic waste at PT X so that the discharged waste does not pollute the surrounding factory environment.

Self-regulation of bed temperature field of the fixed-bed reactor unit by composite-filled oxygen carriers for chemical looping combustion of methane

Fixed-bed reactors (FBRs) are suitable for chemical looping combustion (CLC) of gaseous fuels. However, the non-uniform temperature field such as the formation of hotpots can easily lead to the deactivation of oxygen carriers (OCs), ultimately leading to the degradation of the CLC performance and the durability of the OCs. This work systematically investigates the effect of individual CuO/SiO2 and Fe2O3/Al2O3 OC-filled FBR units on the bed temperature field using a self-built experimental setup to monitor the real-time bed temperature evolution. In addition, a strategy for self-regulating the bed temperature field by composite OCs-filled FBR units is proposed based on the differences in the thermodynamic properties of different OCs, including CuO/SiO2, Fe2O3/Al2O3, Mn2O3/ZrO2 and NiO/ZrO2. It has been found that the radial bed temperature of a single CuO/SiO2 OC-filled FBR unit is significantly higher than that at the central axis, and the bed temperature fluctuates within a range of ± 50 °C throughout the CLC process. The bed temperature of a single Fe2O3/Al2O3 OC-filled FBR unit fluctuated within a range of ± 25 °C during the reduction stage, but the bed temperature increased by nearly 100 °C due to the strong exothermic reaction of the oxidative regeneration of the reduced Fe2O3/Al2O3 OCs. The use of composite OCs-filled FBR units not only improves the CH4 conversion and CO2 selectivity, but also maintains a stable bed temperature fluctuates within a range of ± 15 ℃ during the different reaction stages of the CLC process. The synergistic effect between the OCs contributes to the bed temperature field remaining in a relatively stable state. The results indicate that the rational distribution of composite-filled OCs in FBRs can achieve self-regulation of the bed temperature field to some extent by exploiting the OCs’ endothermic and exothermic properties.

Artificial Intelligence for Hybrid Modeling in Fluid Catalytic Cracking (FCC)

This study reports a novel hybrid model for the prediction of six critical process variables of importance in an industrial-scale FCC (fluid catalytic cracking) riser reactor: vacuum gas oil (VGO) conversion, outlet riser temperature, light cycle oil (LCO), gasoline, light gases, and coke yields. The proposed model is developed via the integration of a computational particle-fluid dynamics (CPFD) methodology with artificial intelligence (AI). The adopted methodology solves the first principle model (FPM) equations numerically using the CPFD Barracuda Virtual Reactor 22.0® software. Based on 216 of these CPFD simulations, the performance of an industrial-scale FCC riser reactor unit was assessed using VGO catalytic cracking kinetics developed at CREC-UWO. The dataset obtained with CPFD is employed for the training and testing of a machine learning (ML) algorithm. This algorithm is based on a multiple output feedforward neural network (FNN) selected to allow one to establish correlations between the riser reactor feeding conditions and its outcoming parameters, with a 0.83 averaged regression coefficient and an overall RMSE of 1.93 being obtained. This research underscores the value of integrating CPFD simulations with ML to optimize industrial processes and enhance their predictive accuracy, offering significant advancements in FCC riser reactor unit operations.