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Records with Subject: Process Design
176. LAPSE:2024.1179
A New Bottom-Hole Assembly Design Method to Maintain Verticality and Reduce Lateral Vibration
June 21, 2024 (v1)
Subject: Process Design
Keywords: bending strain energy, bottom-hole assembly design, forced frequency analysis, lateral vibration, vertical drilling
Well deviation is a prevalent problem in deep oil and gas exploration, leading to a significant increase in drilling costs. The conventional bottom-hole assembly (BHA) anti-deviation design method does not consider the impact of the BHA structure on lateral vibration. This paper proposes an integrated BHA design method that takes into account both anti-deviation and vibration reduction. This method evaluates the BHA’s anti-deviation ability using the drilling trend angle. A negative value of the drilling trend angle indicates that the BHA can correct well deviation. A finite element linearized dynamics method is used to evaluate the lateral vibration intensity of the BHA. This method involves calculating the bending displacement caused by mass imbalance and then determining the magnitude of the bending strain energy based on this displacement. The structural factors affecting the anti-deviation ability and potential lateral vibration intensity of pendulum BHAs and bent-housing mud moto... [more]
177. LAPSE:2024.1148
Reinventing Processes for Sustainability via Process Intensification and Integration
June 21, 2024 (v1)
Subject: Process Design
Keywords: environment, integration, intensification, processes, Sustainability, waste
A waste material cannot truly be called waste when the procedures and technologies have been invented and developed to exploit and utilize it [...]
178. LAPSE:2024.1130
Optimizing Mass Transfer in Multiphase Fermentation: The Role of Drag Models and Physical Conditions
June 21, 2024 (v1)
Subject: Process Design
Keywords: bioreactor, bubble column, diffusion coefficient, drag coefficient, fermentation medium
Detailed knowledge of the flow characteristics, bubble movement, and mass transfer is a prerequisite for the proper design of multiphase bioreactors. Often, mechanistic spatiotemporal models and computational fluid dynamics, which intrinsically require computationally demanding analysis of local interfacial forces, are applied. Typically, such approaches use volumetric mass-transfer coefficient (kLa) models, which have demonstrated their predictive power in water systems. However, are the related results transferrable to multiphase fermentations with different physicochemical properties? This is crucial for the proper design of biotechnological processes. Accordingly, this study investigated a given set of mass transfer data to characterize the fermentation conditions. To prevent time-consuming simulations, computational efforts were reduced using a force balance stationary 0-dimension model. Therefore, a competing set of drag models covering different mechanistic assumptions could be... [more]
179. LAPSE:2024.1120
Hydrodynamics and Mass Transfer in an Airlift Loop Reactor: Comparison between Using Two Kinds of Spargers
June 21, 2024 (v1)
Subject: Process Design
Keywords: airlift loop reactor, gas holdup, jet nozzle, liquid loop velocity, mass transfer, ring orifice distributor
The effects of different spargers on the hydrodynamics and mass transfer of an airlift loop reactor were investigated. The gas holdup, liquid loop velocity, and volumetric mass transfer coefficient of the reactor were tested using a ring orifice distributor and a jet nozzle. The study was conducted in a 6 m high airlift loop reactor at a superficial gas velocity of 0.01~0.04 m/s, and the superficial liquid velocity was maintained at 0.0154 m/s. The results showed that using the jet nozzle provided a higher gas holdup, liquid loop velocity, and mass transfer. When the superficial gas velocity was less than 0.0325 m/s, the liquid loop velocity generated by the jet nozzle was approximately 1.1-fold higher than that generated by the ring orifice distributor, and the disparity in gas holdup between the riser and downcomer enhanced the power of liquid circulation. When the superficial gas velocity was more than 0.0325 m/s, the jet kinetic power dominated the improvement in the liquid loop ve... [more]
180. LAPSE:2024.1107
Sizing and Selection of Pressure Relief Valves for High-Pressure Thermal−Hydraulic Systems
June 21, 2024 (v1)
Subject: Process Design
Keywords: pressure relief valve, pressure vessel, pressurized system, safety
This study covers the critical concerns related to the sizing, selection, installation, maintenance, and testing of pressure safety valves (PSVs). The aim is to ensure the safety of pressurized systems, hydrostatic transmission systems, and hydraulic plants, including process plants, thermal power plants, and nuclear reactor systems. PSVs are devices that ensure the safety and reliability of pressurized vessels, lines, and systems during overpressure events. The task of selecting which PSV features are of greatest value for a specific purpose is complex—especially in the design of a high-pressure experimental thermal−hydraulic facility for hydrostatic and transient testing of the reactor system—when the systems are in the design and development phases and require qualification and demonstration to prove that they have reached a given level of technological readiness. The present study highlights the required steps for users to follow the associated rules, guidelines, and recommendation... [more]
181. LAPSE:2024.1101
Exploring Exergy Performance in Tetrahydrofuran/Water and Acetone/Chloroform Separations
June 21, 2024 (v1)
Subject: Process Design
Keywords: computer modeling, distillation energy efficiency, environmental impact, heat integration, Process Intensification, thermodynamic efficiency
Distillation is significantly influenced by energy costs, prompting a need to explore effective strategies for reducing energy consumption. Among these, heat integration is a key approach, but evaluating its efficiency is paramount. Therefore, this study presents exergy as an energy quality indicator, analyzing irreversibility and efficiencies in tetrahydrofuran/water and acetone/chloroform distillations. Both systems have equimolar feed streams, yielding products with 99.99 mol% purity. The simulations are performed using Aspen Plus™, enabling evaluation at the column level, as a standalone process, or from a lean perspective that considers integration opportunities with other plants. The results show that, despite anticipated energy savings from heat integration, economic viability depends on pressure sensitivity. The results demonstrate that heat-integrated extractive distillation for acetone/chloroform raises utility energy consumption. Exergy calculations comparing standalone and... [more]
182. LAPSE:2024.1035
Supercritical Direct-Methane-to-Methanol Coupled with Gas-to-Wire for Low-Emission Offshore Processing of CO2-Rich Natural Gas: Techno-Economic and Thermodynamic Analyses
June 7, 2024 (v1)
Subject: Process Design
Keywords: CO2 dehydration, direct methane-to-methanol, gas-to-wire, natural gas combined cycle, post-combustion carbon capture, supercritical water, thermodynamic analysis
A greater H/C ratio and energy demand are factors that boost natural gas conversion into electricity. The Brazilian offshore pre-salt basin has large reserves of CO2-rich associated gas. Selling this gas requires high-depth long-distance subsea pipelines, making gas-to-pipe costly; in particular, gas-to-wire instead of gas-to-pipe is more practical since it is easier to transmit electricity via long subsea distances. This research proposes and investigates an innovative low-emission gas-to-wire alternative consisting of installing supercritical direct-methane-to-methanol upstream to gas-to-wire, which is embedded in an exhaust-gas recycle loop that reduces the subsequent carbon capture costs. The process exports methanol and electricity from remote offshore oil-and-gas fields with available CO2-rich natural gas, while capturing CO2. Techno-economic, thermodynamic and lost work analyses assess the alternative. Supercritical direct-methane-to-methanol is conducted in supercritical water... [more]
183. LAPSE:2024.1010
Mechanical Recycling of Post-Industrial PC/ABS Blends from the Automotive Sector by Mixture Design
June 7, 2024 (v1)
Subject: Process Design
Keywords: automotive scraps, design of experiments, mechanical recycling, mixture design, PC/ABS
The widespread use of plastic materials poses significant environmental challenges, which have promoted a growing call for a circular approach to such materials, emphasizing waste reintegration into production. From this perspective, the present study focuses on analyzing a post-industrial recycled stream of chrome-plated automotive scraps composed of acrylonitrile−butadiene−styrene (ABS), polycarbonate (PC), and a commercial PC/ABS blend. The batch-to-batch varying proportions of these constituents make control of the recycled materials’ quality challenging. To address this problem, we formulated an I-optimal mixture design model using the infrared absorbance ratio of selected peaks and Izod impact resistance results for injection-molded samples as inputs to determine the composition of each batch quickly. The two model equations (adjusted R2 > 0.97) obtained, based on cubic expression and regressed from data obtained from 27 mixtures with known compositions, were combined into a sing... [more]
184. LAPSE:2024.1008
New Method for Capacity Evaluation of Offshore Low-Permeability Reservoirs with Natural Fractures
June 7, 2024 (v1)
Subject: Process Design
Keywords: capacity evaluation, fractal parameters, natural fractures, offshore low-permeability reservoirs, threshold pressure gradient
In recent years, the development of two offshore low-permeability oil fields has revealed unexpected challenges. The actual productivity of these fields significantly deviates from the designed capacity. Some wells even outperform the expectations for low-permeability limestone fields. This discrepancy primarily stems from a lack of accurate understanding of natural fractures before and after drilling, resulting in substantial errors in capacity assessment. This paper addresses these challenges by proposing a new production capacity model and evaluation method for both vertical and horizontal wells in low-permeability limestone reservoirs. The method leverages logging curve data, incorporating vertical gradation and fractal analysis to effectively represent the fracture’s complexity and connectivity. It uniquely considers factors such as fracture fractal dimensions, threshold pressure, and stress sensitivity, significantly enhancing prediction accuracy. Furthermore, by analyzing the lo... [more]
185. LAPSE:2024.1006
Enhancing Single- and Two-Stage Anaerobic Digestion of Thickened Waste-Activated Sludge through FNA-Heat Pretreatment
June 7, 2024 (v1)
Subject: Process Design
Keywords: acidogenic fermentation, methane production, solubilization, thermochemical pretreatment, thickened waste-activated sludge, two-stage anaerobic digestion
This study aimed to investigate the effect of combined Free Nitrous Acid (FNA)-Heat (i.e., FNH) pretreatment on single- and two-stage anaerobic digestion (AD) of thickened waste-activated sludge (TWAS). Single-stage AD was conducted in batches, while two-stage AD involved acidogenic fermentation under semi-continuous flow followed by batch methanogenesis. FNH pretreatment was applied before the acidogenic stage, using 1.4 mg HNO2-N/L FNA concentration at 25 °C, 37 °C, and 60 °C for 24 h. Among the scenarios, the most promising results were observed with two-stage AD fed with FNH-pretreated TWAS at 60 °C, showing higher COD solubilization and a reduction in volatile solids. Combined FNA-Heat pretreatment in two-stage AD yielded elevated methane production (363−415 mL CH4/g VS added) compared to single-stage digestion. Methane yields from FNA-Heat pretreated single-stage ranged from 332 to 347 mL CH4/g VS added, contrasting with 212 mL CH4/g VS added for untreated TWAS. Methane generatio... [more]
186. LAPSE:2024.0970
Immobilized Lipases—A Versatile Industrial Tool for Catalyzing Transesterification of Phytosterols Solubilized in Plant Oils to Produce Their Fatty Acid Esters
June 7, 2024 (v1)
Subject: Process Design
Keywords: direct transesterification reactions, esterification, fatty acyl group donors, immobilized lipases, phytosterol esters, phytosterols
The conjugation of phytosterols (PSs) with fatty acids results in producing phytosterol esters (PSEs) characterized by enhanced lipophilicity and improved functional properties of major interest in food and nutraceutical applications. The use of immobilized lipases to catalyze direct transesterification reactions between PSs and plant oils to form PSEs as a green alternative to conventional chemical production methods has attracted interest during the last two decades. The low solubility of PSs in common plant oil triglycerides, typically below 3% at ambient temperatures, remains the main challenge for bringing lipase-catalyzed direct transesterification reactions of PSs and oil triglycerides to commercial scales. This study focuses on the enzymatic synthesis of PSEs starting from solubilized PSs at concentrations of up to 30% wt./wt. of oil mixtures comprising fatty acid ethyl esters (FAEEs), monoglycerides (MGs), diglycerides (DGs), and triglycerides (TGs) as a homogeneous medium for... [more]
187. LAPSE:2024.0944
Quality of Mixedness Using Information Entropy in a Counter-Current Three-Phase Bubble Column
June 7, 2024 (v1)
Subject: Process Design
Keywords: information entropy, intrinsic mass transfer, mass transfer efficiency, mixedness, slurry bubble column
Knowledge of mixing phenomena is of great value in the mineral and other chemical and biochemical industries. This work aims to analyze the quality of mixedness (QM), the intrinsic mass transfer (MT) number, and the MT efficiency based on information entropy theory in the counter-current microstructured slurry bubble column. A thorough analysis is conducted to assess the effects of particle loading, gas and slurry velocity, and axial variation on the QM. The range of gas velocity, slurry velocity, particle size, and particle loading was 0.011−0.075 m/s, 0.018−0.058 m/s, 242.72−408.31 μm, and 15.54−88.94 kg/m3, respectively. QM is a time-dependent parameter, and the concept of contact time has been used for scale-up purposes. The maximum QM was achieved at dimensionless times of 0.40 × 10−3, 0.15 × 10−3, and 0.85 × 10−3 for the maximum superficial gas velocity, particle loading, and axial height, respectively. The gas velocity positively influenced both the intrinsic MT number and its e... [more]
188. LAPSE:2024.0853
Influence of the Rotation Speed on the Internal Flow Characteristics of an Aircraft Fuel Gear Pump
June 7, 2024 (v1)
Subject: Process Design
Keywords: cavitation area, cavitation evolution, gear engagement, gear pump, rotation speed
A gear pump is a key rotary-displacement pump for aircraft fuel transportation in the aerospace industry. Due to the great ratio of power-to-weight condition demanded for gear pumps in aircraft fuel transportation systems, the parameter of the rotation speed is a matter of extreme concern affecting internal flow characteristics that determines the adverse effects of cavitation, fuel trapping, and vibration. However, the flow characteristics of an aircraft fuel gear pump influenced by the rotation speed have not been elaborated upon on yet. In this research, the flow characteristics of an aircraft fuel gear pump were studied by considering the influence of the rotation speed. An experiment for testing the external performance of an aircraft fuel gear pump was performed, and a corresponding numerical simulation of a gas−liquid two-phase flow was employed. Distributions of the velocity and pressure at the central cross-sections and their monitored transient developments were comparatively... [more]
189. LAPSE:2024.0823
Design of a Bioreactor for Aerobic Biodegradation of Biowaste Based on Insight into Its Composition and Estimated Process Parameters
June 7, 2024 (v1)
Subject: Process Design
Keywords: biodegradation model, biowaste, composting, kinetic parameters
Biowaste, which often accounts for more than 50% of municipal waste, is an environmental problem if disposed of improperly in landfills but has great potential to achieve the recycling targets set out in Directive (EU) 2018/851. Despite the knowledge in theory and practice about the processing of biowaste and the benefits of recycling, there is a lack of methodological approaches in describing the process of aerobic biodegradation in a concise and suitable way for decision makers, environmental engineers, and project designers. This paper presents how basic data on the properties of biowaste can be used, using theoretical models, to determine basic indicators of the dynamics and material balance of the process. The maximum rate of CO2 generation on the 4th day was Rm = 45.3 g/d, with the potential of available, readily biodegradable components of the biowaste sample of P = 526 g CO2/kg VS. A substrate conversion of 51.7% was achieved in the bioreactor by the 17th day of treatment. The... [more]
190. LAPSE:2024.0808
Recovery of Strategic Metals from Waste Printed Circuit Boards with Deep Eutectic Solvents and Ionic Liquids
June 7, 2024 (v1)
Subject: Process Design
Keywords: DESs, ionic liquids, metals extraction/recovery, spent solid WPCBs
The recycling of metals from waste printed circuit boards (WPCBs) has been presented as a solid−liquid extraction process using two deep eutectic solvents (DESs) and four ionic liquids (ILs). The extraction and separation of Cu(II), Ag(I), and other metals, such as Al(III), Fe(II), and Zn(II), from the solid WPCBs (after the physical, mechanical, and thermal pre-treatments) with different solvents are demonstrated. Two popular DESs were used to recover valuable metal ions: (1) choline chloride + malonic acid, 1:1, and (2) choline chloride + ethylene glycol, 1:2. The extraction efficiencies of DES 1 after two extraction and two stripping stages were only 15.7 wt% for Cu(II) and 17.6 wt% for Ag(I). The obtained results were compared with those obtained with four newly synthetized ILs as follows: didecyldimethylammonium propionate ([N10,10,1,1][C2H5COO]), didecylmethylammonium hydrogen sulphate ([N10,10,1,H][HSO4]), didecyldimethylammonium dihydrogen phosphate ([N10,10,1,1][H2PO4]), and t... [more]
191. LAPSE:2024.0776
Design and Sensitivity Analysis of Mechanically Actuated Digital Radial Piston Pumps
June 6, 2024 (v1)
Subject: Process Design
Keywords: digital hydraulics, fluid power, pump design, variable displacement
One major challenge in fluid power is the improvement and optimization of the efficiency of mobile hydraulic systems. Conventional fluid power systems often exhibit relatively low overall efficiencies caused by inefficiencies in the various components, such as a prime mover, variable displacement pump, valves, fittings, hoses, and actuators. While each component contributes to the losses in the overall system, the pump converts the mechanical shaft energy from the prime mover to energy transmitted hydraulically and is one of the most crucial components impacting overall system efficiency. Using on/off technologies, new pump architectures have enabled the opportunity to increase the efficiency over conventional designs using positive sealing valves in place of conventional port plate designs. This work proposes, investigates, and assesses the development and optimization of a digital variable displacement pump using a novel cam actuation technique on radial piston pumps. The novelty of... [more]
192. LAPSE:2024.0748
Effects of Diameter Parameters on Gas Flow Field Characteristics in Cyclones: An Experimental Investigation
June 6, 2024 (v1)
Subject: Process Design
Keywords: cyclone, cylinder diameter, dominant frequency, dynamic characteristics, flow field, vortex finder diameter
The flow field characteristic is crucial for the separation process of cyclones, which includes time−mean and dynamic characteristics. The structural parameters of the cyclone have an important influence on the internal flow field characteristics, among which the cylinder diameter and vortex finder diameter are important structural parameters. This experimental study aimed to assess the effects of diameter parameters on the flow field characteristics of cyclones, especially the dynamic characteristics, which have received less attention in the literature. A hot wire anemometer (HWA) was employed in measuring the instantaneous tangential velocities in cyclones with different cylinder and vortex finder diameters. Time and frequency domain analyses of the measured data revealed that the diameter parameters of cyclones affected not only the distributions of the time−mean and instantaneous tangent velocities but also the intensity and dominant frequency of the instantaneous tangential veloc... [more]
193. LAPSE:2024.0747
Proposal of Industry 5.0-Enabled Sustainability of Product−Service Systems and Its Quantitative Multi-Criteria Decision-Making Method
June 6, 2024 (v1)
Subject: Process Design
Keywords: analytic hierarchy process, data envelopment analysis, design for sustainability, Industry 4.0, Industry 5.0, multi-criteria decision making, product–service system, Sustainability
In the wake of Industry 4.0, the ubiquitous internet of things provides big data to potentially quantify the environmental footprint of green products. Further, as the concept of Industry 5.0 emphasizes, the increasing mass customization production makes the product configurations full of individuation and diversification. Driven by these fundamental changes, the design for sustainability of a high-mix low-volume product−service system faces the increasingly deep coupling of technology-driven product solutions and value-driven human-centric goals. The multi-criteria decision making of sustainability issues is prone to fall into the complex, contradictory, fragmented, and opaque flood of information. To this end, this work presents a data-driven quantitative method for the sustainability assessment of product−service systems by integrating analytic hierarchy process (AHP) and data envelopment analysis (DEA) methods to measure the sustainability of customized products and promote the Ind... [more]
194. LAPSE:2024.0704
Process Intensification in Human Pluripotent Stem Cell Expansion with Microcarriers
June 6, 2024 (v1)
Subject: Process Design
Keywords: microcarriers, perfusion, single-use, stirred bioreactor, upstream processing
Given the demands human induced pluripotent stem cell (hiPSC)-based therapeutics place on manufacturing, process intensification strategies which rapidly ensure the desired cell quality and quantity should be considered. Within the context of antibody and vaccine manufacturing, one-step inoculation has emerged as an effective strategy for intensifying the upstream process. This study therefore evaluated whether this approach could be applied to the expansion of hiPSCs in flasks under static and in microcarrier-operated stirred bioreactors under dynamic conditions. Our findings demonstrated that high density working cell banks containing hiPSCs at concentrations of up to 100 × 106 cells mL−1 in CryoStor® CS10 did not impair cell growth and quality upon thawing. Furthermore, while cell distribution, growth, and viability were comparable to routinely passaged hiPSCs, those subjected to one-step inoculation and expansion on microcarriers under stirred conditions were characterized by impro... [more]
195. LAPSE:2024.0689
Six-Tower Pressure Swing Adsorption Demonstration Animation
June 6, 2024 (v1)
Subject: Process Design
Keywords: animation, pressure swing adsorption, visualization
The Pressure Swing Adsorption (PSA) technique is a widely embraced automated method for gas separation within the industrial sector, prized for its operational simplicity and substantial economic benefits. In practice, the process typically involves the use of multiple towers to facilitate the completion of the PSA cycle. However, with the increasing number of towers in a PSA system, the intricacies of the cyclic process tend to amplify, posing challenges for novices attempting to grasp the mechanics of a six-tower PSA cycle. Utilizing animation can facilitate the process of comprehending these complex techniques by presenting them in a simplified and visually engaging format. Therefore, our research group has designed an animated depiction of a six-tower PSA device, predicated on the prototype established in our laboratory. This animation furnishes an inclusive demonstration of a complete cycle, encompassing twelve steps, pertaining to the operation of a six-tower PSA. It is our aspir... [more]
196. LAPSE:2024.0667
Physical and Chemical Properties of Pachycymbiola brasiliana Eggshells—From Application to Separative Processes
June 6, 2024 (v1)
Subject: Process Design
Keywords: biopolymer, mechanical stability, methylene blue separation, Pachycymbiola brasiliana, water sorption
is a marine snail found in the seas adjacent to the coasts of Brazil, Uruguay, and Argentina, whose eggshells are composed primarily of chitin. In this work, Pachycymbiola brasiliana eggshells were used to prepare films and their structural and physicochemical characteristics were investigated. The main focus was on their mechanical stability, water sorption, and methylene blue rejection. From the FTIR spectra, the bands corresponding to chitin were identified. The differential scanning calorimetric (DSC) data showed that the biopolymer has a glass transition temperature of around 32 °C. The morphological analysis was carried out by using SEM and XRD. The study of the films’ mechanical stability showed an improvement with an increase in water activity. Regarding the methylene blue separation processes, a low permeation through the film and a rejection rate of 94 to 99% were demonstrated. Therefore, Pachycymbiola brasiliana eggshell can be considered a promising source of biopolymers fo... [more]
197. LAPSE:2024.0565
Optimal Design and Discrete Element Method Model Development of the Acute Angle Hoe Opener for No-Till System
June 5, 2024 (v1)
Subject: Process Design
Keywords: draft force, seedbed, seeds distribution, soil aggregations, soil compaction
A specialized hoe opener was engineered for no-till systems to apply substantial amounts of wheat seeds and granular fertilizers, effectively suppressing early stage weeds. This distinctive hoe opener plants wheat seeds within a 120 mm wide horizontal band, positioning granular fertilizers precisely at the band’s center, all accomplished in a single pass. Notably, the design excels at covering the fertilizer with soil aggregates, compacting it through a wheat separator, and concurrently depositing wheat seeds from above. Our primary research objectives centered on achieving a consistent seedbed post-fertilizer application and ensuring a uniform distribution of wheat seeds within the horizontal band. The DEM (Discrete Element Method) was exploited to optimize the hoe opener’s parameters. Through extensive simulations and comparisons with experimental outcomes, an optimal wing orifice AB length of 60 mm was identified, effectively covering granular fertilizers with soil aggregates and ac... [more]
198. LAPSE:2024.0512
Characteristic Analysis and Coating Application of the Innovative HVOF System Based on the Digital Model
June 5, 2024 (v1)
Subject: Process Design
Keywords: AMESim, digital model, dynamic characteristics, HVOF, spray parameter design
In view of the poor working conditions, high cost and time-consuming parameter design of the traditional spray process, an innovative HVOF thermal spray system based on the digital model has been established by this study to improve coating performance and optimize scheme design rapidly. In particular, the digital model of the oxygen/kerosene HVOF spray system is designed on the AMESim multidisciplinary simulation platform for the first time, and the engineering prototype has been successfully developed. Thus, an efficient design method based on the digital model was proposed, according to which the spray control parameters such as oxygen and kerosene flow are obtained conveniently under a combustion chamber pressure of 1.0 MPa and 2.0 MPa, respectively. The error between the simulation and experiment results was generally less than 5%, and the dynamic characteristics of the key components in the actual spray system were well predicted, suggesting that the dynamic response time of the... [more]
199. LAPSE:2024.0495
Thermodynamically Efficient, Low-Emission Gas-to-Wire for Carbon Dioxide-Rich Natural Gas: Exhaust Gas Recycle and Rankine Cycle Intensifications
June 5, 2024 (v1)
Subject: Process Design
Keywords: carbon dioxide monetization, CCS, exhaust gas recycle, gas-to-wire, multi-criteria analysis, Natural Gas, post-combustion carbon capture, Process Intensification, thermodynamic analysis
Onshore gas-to-wire is considered for 6.5 MMSm3/d of natural gas, with 44% mol carbon dioxide coming from offshore deep-water oil and gas fields. Base-case GTW-CONV is a conventional natural gas combined cycle, with a single-pressure Rankine cycle and 100% carbon dioxide emissions. The second variant, GTW-CCS, results from GTW-CONV with the addition of post-combustion aqueous monoethanolamine carbon capture, coupled to carbon dioxide dispatch to enhance oil recovery. Despite investment and power penalties, GTW-CCS generates both environmental and economic benefits due to carbon dioxide’s monetization for enhanced oil production. The third variant, GTW-CCS-EGR, adds two intensification layers over GTW-CCS, as follows: exhaust gas recycle and a triple-pressure Rankine cycle. Exhaust gas recycle is a beneficial intensification for carbon capture, bringing a 60% flue gas reduction (reduces column’s diameters) and a more than 100% increase in flue gas carbon dioxide content (increases drivi... [more]
200. LAPSE:2024.0465
Improving Polyp Segmentation with Boundary-Assisted Guidance and Cross-Scale Interaction Fusion Transformer Network
June 5, 2024 (v1)
Subject: Process Design
Keywords: boundary-assisted guidance, cross-scale interaction, polyp segmentation, transformer
Efficient and precise colorectal polyp segmentation has significant implications for screening colorectal polyps. Although network variants derived from the Transformer network have high accuracy in segmenting colorectal polyps with complex shapes, they have two main shortcomings: (1) multi-level semantic information at the output of the encoder may result in information loss during the fusion process and (2) failure to adequately suppress background noise during segmentation. To address these challenges, we propose a cross-scale interaction fusion transformer for polyp segmentation (CIFFormer). Firstly, a novel feature supplement module (FSM) supplements the missing details and explores potential features to enhance the feature representations. Additionally, to mitigate the interference of background noise, we designed a cross-scale interactive fusion module (CIFM) that combines feature information between different layers to obtain more multi-scale and discriminative representative f... [more]
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