Column Operation Research Articles

Optimizing the max-min function with a constraint on a two-sided linear system

<abstract><p>The behavior of discrete-event systems, in which the individual components move from event to event rather than varying continuously through time, is often described by systems of linear equations in max-min algebra, in which classical addition and multiplication are replaced by $ \oplus $ and $ {\otimes} $, representing maximum and minimum, respectively. Max-min equations have found a broad area of applications in causal models, which emphasize relationships between input and output variables. Many practical situations can be described using max-min systems of linear equations. We shall deal with a two-sided max-min system of linear equations with unknown column vector $ x $ of the form $ A{\otimes} x{\oplus} c = B{\otimes} x{\oplus} d $, where $ A $, $ B $ are given square matrices, $ c $, $ d $ are column vectors and operations $ \oplus $ and $ {\otimes} $ are extended to matrices and vectors in the same way as in the classical algebra. We give an equivalent condition for its solvability. For a given max-min objective function $ f $, we consider optimization problem of type $ f^\top{\otimes} x\rightarrow \max\text{ or } \min $ constraint to $ A{\otimes} x{\oplus} c = B{\otimes} x{\oplus} d $. We solve the equation in the form $ f(x) = v $ on the set of solutions of the equation $ A{\otimes} x{\oplus} c = B{\otimes} x{\oplus} d $ and extend the problem to the case of an interval function $ {{\boldsymbol{f}}} $ and an interval value $ {{\boldsymbol{v}}} $. We define several types of the reachability of the interval value $ {{\boldsymbol{v}}} $ by the interval function $ {{\boldsymbol{f}}} $ and provide equivalent conditions for them.</p></abstract>

In Situ Fabrication and Characterization of g-C3N4 onto Cellulose Nanofibers and Selective Separation of Heavy Metal Ions.

Graphitic carbon nitride nanosheets were synthesized onto cellulose nanofiber surfaces utilizing an eco-friendly salt melt approach. The fabricated material CNF@C3N4 selectively removes Ni(II) and Cu(II) from electroplating wastewater samples. The immobilization of g-C3N4 on solid substrates eases handling of nanomaterial in a flow-through approach and mitigates sorbent loss during column operations. Characterization techniques such as scanning electron microscopy, tunneling electron microscopy, and X-ray photoelectron microscopy were employed to analyze the surface morphology and chemical bonding within the synthesized material. Selective Cu(II) and Ni(II) sorption predominantly arises from the soft-soft interaction between metal ions and associated nitrogen groups. An inner-sphere surface complexation mechanism effectively elucidated the interaction dynamics between the metal and CNF@C3N4. Experimental findings demonstrated satisfactory separation of Ni(II) and Cu(II) ions, with the extraction of 340.0 and 385.0 mg g-1 of material, respectively. Additionally, the devised technique was executed for the preconcentration and quantification of trace metals ions in water samples with a detection limit and limit of quantification of 0.06 and 0.20 μg L-1, respectively.

Parallel private information retrieval protocol with index anonymity for untrusted databases

Private information retrieval (PIR) enables a client to search data from a single (or multiple) untrusted server, without revealing which entry was queried. PIR can be divided into two categories: information-theoretic PIR (IT-PIR) and computational PIR (CPIR). However, there is a deployment challenge with IT-PIR because the non-collusion assumption is difficult to implement in practice. Meanwhile, due to the fact that CPIR involves performing cryptographic operations on each element, its performance significantly decreases as the size and number of database entries increase. To overcome these problems, based on homomorphic encryption, this paper presents a parallel PIR (ParPIR) with index anonymity for untrusted databases, which uses the batch encoding to compress request size. Furthermore, our ParPIR eliminates computationally expensive ciphertext multiplication operations, which improves the response time. Moreover, our ParPIR packs multiple responses through rotation column operations on ciphertext, thereby reducing the response size. Compared to previous PIR protocols, the offline time in our ParPIR has almost 1∼63× improvement; the online time in our ParPIR decreases by at least 49.9∼98.9%. Meanwhile, although the request size of our ParPIR has a 0∼31× increase, the response size of our ParPIR has a 0∼4095× improvement.

Analysis of operation modes of a counter ow column of chemical isotope exchange of hydrogen with water with independent flows of water and hydrogen

As a result of a theoretical analysis of the operation of a countercurrent column of chemical isotope exchange (CIE) of hydrogen with water in the mode with independent ows of hydrogen and water, it has been shown that there are temperature-dependent maximum values of the molar ratio of hydrogen and water ows at which the separating power of the column with respect to isotope mixtures protium-tritium and protium-deuterium are signi cantly reduced. Variants of the operation of the CIE column were experimentally studied under the condition that the condensate of water vapor is returned to the column from the outgoing steam-gas stream or without it. The results of the experiments agree with the theoretical analysis carried out.

Robust method for chromatogram shape analysis to improve early detection of performance drifts and adverse changes in process parameters during purification column operations.

The biopharmaceutical industry is under increased pressure to maximize efficiency, enhance quality compliance, and reduce the cost of drug substance manufacturing. Ways to reduce costs associated with manufacturing of complex biological molecules include maximizing efficiency of chromatography purification steps. For example, process analytical technology (PAT) tools can be employed to improve column resin life, prevent column operating failures, and decrease the time it takes to solve investigations of process deviations. We developed a robust method to probe the shape of the chromatogram for indications of column failure or detrimental changes in the process. The approach herein utilizes raw data obtained from manufacturing followed by a pre-processing routine to align chromatograms and patch together the different chromatogram phases in preparation for multivariate analysis. A principal component analysis (PCA) was performed on the standardized chromatograms to compare different batches, and resulted in the identification specific process change that affected the profile. In addition, changes in the chromatogram peaks were used to create predictive models for impurity clearance. This approach has the potential for early detection of column processing issues, improving timely resolution in large-scale chromatographic operations.

Highly efficient solid phase extraction of uranium with TOPO-menthol based eutectic solvent as stationary phase from acidic feed relevant to front-end applications

Novel methods of separation and purification are envisaged for natural uranium, containing 0.7% of fissile 235U, a precious resource that fuels nuclear power plants. The present study demonstrates Solid phase extraction (SPE) of uranium as a sustainable alternative to conventional liquid-liquid extraction, leading to minimisation of organic inventory and enhancement of ease of operation concerning usage of viscous eutectic solvent. Overcoming the issue of the low solubility of organophosphorus extractant tri-octyl phosphine oxide (TOPO) in a hydrocarbon diluent, the aqueous insoluble, non-ionic eutectic solvent could be prepared with biodegradable menthol having TOPO: menthol mole ratio of 1:2 (MT2), 1:3 (MT3) and 1:4 (MT4). Eutectic solvents were sorbed on radio chemically stable Chromosorb W resin as solid support (MTC2, MTC3, MTC4), with loading of 45% for MTC2 and 40% for both MTC3 and MTC4, confirmed by weight difference and thermogravimetry. Batch sorption studies of U(VI) from nitric acid medium revealed attainment of equilibrium at 60 min., following a pseudo-second-order rate equation, Langmuir adsorption isotherm and a static capacity of 19 mg g−1. The U(VI) uptake was found to increase with the increase in acid molarity indicating solvating mechanism of extraction (KD = 1240 ± 4, 4 M HNO3). Recyclability was established and stripping was effective with 0.5 M HNO3. Column operation was also successfully demonstrated (breakthrough capacity = 18.9 mg g−1). The U(VI) uptake of >98% was indicated for nitric acid-digested crude yellow cake matrices viz. sodium diuranate (SDU), magnesium diuranate (MDU) and heat-treated uranium peroxide (HTUP). For higher matrix content, near complete uranium uptake and suppression of extraction of representative impurities (Fe, Mn, Ni, Ce) was revealed indicating facile uranium separation and purification from matrices relevant to the front end of the nuclear fuel cycle.

Machine Learning Model for Predicting the Performance of Activated Carbon Column for the Removal of Volatile Organic Compounds (VOCs)

Objectives : In this study, a performance prediction model for a pilot-scale VOC adsorption column was developed using ANN algorithm. We compared the prediction accuracy of the mathematical models (Thomas model and Yan model) and the multiple linear regression model with that of ANN. This study showed the applicability of the ANN model for predicting the performance of activated carbon columns.Methods : The adsorption module contained 79.8 kg/module of wood-based activated carbon. The gas with 800 ppm-THC of toluene flowed downward from the top at about 5,700 m<sup>3</sup>/h. The breakthrough point was taken as 200 ppm-THC, the same as VOC emission regulation. The desorption was carried out using 130 m<sup>3</sup>/h of hot gas flowing upwards with reduced pressure (-150 to -200 mbar) and high heat (170℃). Adsorption and desorption cycles were conducted 6 times using 3 batches of activated carbon modules. Thomas model, Yan model, multiple linear regression model, and ANN model were developed to predict the breakthrough of <i>C<sub>out</sub>/C<sub>in</sub></i> .Results and Discussion : The Thomas model and the Yan model provided the R<sup>2</sup> values of 0.25 and 0.28, respectively, for predicting the <i>C<sub>out</sub>/C<sub>in</sub></i> of all adsorption module batches and cycles, and the prediction accuracies were low. This could be because these two models do not consider temperature and pressure change operating conditions in the models. Also, the prediction accuracy of <i>C<sub>out</sub>/C<sub>in</sub></i> was low when the initial inlet concentration and flow rate conditions were different for each batch. The multiple linear regression model considers all operating factors in the model, but the prediction accuracy of <i>C<sub>out</sub>/C<sub>in</sub></i> was low as R<sup>2</sup> of 0.45. On the other hand, the ANN model predicted the <i>C<sub>out</sub>/C<sub>in</sub></i> with R<sup>2</sup> higher than 0.97 for all adsorption module batches. In particular, even with the non-ideal data, the ANN model derived a breakthrough of <i>C<sub>out</sub>/C<sub>in</sub></i> close to the experimental value.Conclusion : The ANN model provided high prediction performance for the breakthrough of <i>C<sub>out</sub>/C<sub>in</sub></i> even under non-ideal operation conditions and was expected to be helpful for actual THC adsorption column operation. The accuracy of the ANN model will be further improved if data are accumulated under various conditions.

Application of Ultra Fine Bubbles for Deoxygenation of Produced Water and Tap Water via Nitrogen Purging Scheme

In this study, we present our findings from examining a gas lift tower for produced and tap water de-oxygenation, applying the nitrogen purging at an ultra-fine bubble scale (18 μm average size). The experiments were conducted for produced water samples grafted with polyacrylamide concentration 300 ppm with a measured bulk viscosity of 5 mPa.s. Upon applying a series of experimental sets, 0 ppm DO was attained in all examined operational schemes (semi batch and once through) within various time limits, depending on the water level in the column. Considering the zero DO level as an objective function, the results showed an improvement of 5.7–14 folds in reaching the 0 ppm DO upon experimenting with the ultra-fine bubble purging in different schemes, compared with of the results obtained from the ordinary bubble size (mm scale). The results show that DO reached < 10 ppb within 23 minutes with nitrogen flowrate 3 L/min while DO reaching < 10 ppb within 28 minutes with nitrogen flowrate 5 L/min. Furthermore, implementing the ultra-fine bubble nitrogen purging was successful in running the de-oxygenation tower in a full continuous mode at a balanced inlet/outlet water flow rate. This has been done after reaching stability in the column operation (lasting around 1 hour for 422 L of examined water sample). The stable fine bubbles cloud in the column was quite efficient in treating water influent stream to be exited directly at 0 ppm DO within the same effluent flow rate. The treatment efficiency has shown an increase with increasing water level in the column, resulting in a denser layer/cloud of fine bubbles. This result suggests a unique approach/solution for the complete removal of DO from produced water, which is accounted effective to be adopted industrially

Operation of Distillation Columns Using Model Predictive Control Based on Dynamic Mode Decomposition Method

Operation of Distillation Columns Using Model Predictive Control Based on Dynamic Mode Decomposition Method

Breakthrough curve analysis of phosphorylated hazelnut shell waste in column operation for continuous harvesting of lithium from water

In batch-scale operations, biosorption employing phosphorylated hazelnut shell waste (FHS) revealed excellent lithium removal and recovery efficiency. Scaling up and implementing packed bed column systems necessitates further design and performance optimization. Lithium biosorption via FHS was investigated utilizing a continuous-flow packed-bed column operated under various flow rates and bed heights to remove Li to ultra-low levels and recover it. The Li biosorption capacity of the FHS column was unaffected by the bed height, however, when the flow rate was increased, the capacity of the FHS column decreased. The breakthrough time, exhaustion time, and uptake capacity of the column bed increased with increasing column bed height, whereas they decreased with increasing influent flow rate. At flow rates of 0.25, 0.5, and 1.0 mL/min, bed volumes (BVs, mL solution/mL biosorbent) at the breakthrough point were found to be 477, 369, and 347, respectively, with the required BVs for total saturation point of 941, 911, and 829, while the total capacity was calculated as 22.29, 20.07, and 17.69 mg Li/g sorbent. In the 1.0, 1.5, and 2.0 cm height columns filled with FHS, the breakthrough times were 282, 366, and 433 min, respectively, whereas the periods required for saturation were 781, 897, and 1033 min. The three conventional breakthrough models of the Thomas, Yoon-Nelson, and Modified Dose-Response (MDR) were used to properly estimate the whole breakthrough behavior of the FHS column and the characteristic model parameters. Li's extremely favorable separation utilizing FHS was evidenced by the steep S-shape of the breakthrough curves for both parameters flow rate and bed height. The reusability of FHS was demonstrated by operating the packed bed column in multi-cycle mode, with no appreciable loss in column performance.

Facile preparation of diblock copolymers as functional surfaces for protein chromatography

AbstractStationary phase plays a crucial role in the operation of a protein chromatography column. Conventional resins composed of acrylic polymers and their derivatives contribute to heterogeneity of the packing of stationary phase inside these columns. Alternative polymer combinations through customized surface functionalization schemes which consist of multiple steps using static coating techniques are well known. In comparison, it is hypothesized that single‐step scheme is sufficient to obtain porous adsorbents as stationary phase for tuning surface morphology and protein immobilization. To overcome the challenge of heterogeneous packing and ease of fabrication at laboratory scale, change in the form factor of separation materials has been proposed in the form of functional copolymer surfaces. In the present work, an amphiphilic, block copolymer, poly(methyl methacrylate‐co‐methacrylic acid) has been chosen and fully characterized for its potential usage in protein chromatography. Hydrophilicity of the acrylic copolymer and abundance of carboxyl groups inherently on the copolymer surface have been successfully demonstrated through contact angle measurements, Fourier transform infrared (FTIR) and X‐ray photoelectron spectroscopy (XPS) studies. Morphological studies indicate presence of a microporous region (nearly 1.3 μm average pore size) that could be beneficial as a cation exchange media as part of the stationary phase in protein chromatography.

Design and operation of a packed pilot scale distillation column for tire pyrolysis oil: Towards the recovery of value-added raw materials

This work describes the key features involved in the design and operation of a pilot scale distillation column for the recovery of value-added products from tire pyrolysis oil (TPO), as part of the BLACKCYCLE project. The distillation unit was designed using engineering heuristic rules, simulated distillation (SimDist) data and Aspen Hysys ® modeling. The distillation plant consists of a packed column with a nominal throughput of 20 kg/h, and is classified at the fifth technology readiness level (TRL-5). The commissioning and results of long-term experimental campaigns for validation purposes are also presented. In this way, important information is gathered for the design of larger plants. The distillation unit was tested and validated using TPO produced from a pilot scale continuous single-auger pyrolysis plant. A first distillation was performed yielding a heavy fraction (HF-1) with properties suitable for carbon black production, while the light fraction (LF-1) includes the presence of value-added chemicals such as benzene, toluene, ethylbenzene and xylenes (BTEX) and limonene. The LF-1 was also used for a second distillation, producing a stream high in limonene at the bottom (HF-2), and another one high in BTEX compounds at the top (LF-2), which are valuable raw materials for polymer production and petrochemicals, respectively. The key results obtained here are expected to provide an outstanding impetus for the circular economy of complex streams such as end-of-life tires (ELTs) by combining pyrolysis and distillation technologies.

Optimizing metal recovery from slag leaching solutions: Advanced ion exchange techniques for sustainable resource extraction

Metal recovery through ion exchange (IX) is a promising strategy for resource extraction and environmental conservation. We assessed the efficacy of IX in recovering metal ions from slag leachates sourced from a Chilean copper processing plant. At pH 4.3, selective precipitation removed over 90 % of Fe(III) and Al(III). In batch mode, an iminodiacetic-functionalized resin selectively adsorbed Fe(III) and Al(III) ions, outcompeting other valuable metals. Optimizing pH and matrix composition in column operations boosted nickel recovery to 0.65 eq/L using a bispicolylamine-functionalized resin. A 3.5 % NH4OH solution proved effective for nickel elution, reaching 10 g/L peak concentration. The successful upscaling of the process from a 10 mL to a 100 mL bed volume demonstrates positive insights for industrial application, enabling efficient nickel recovery from larger volumes of water. SEM analysis revealed the physical state on the resin, and metal ion interactions, which verified the interpretations from water analyses, reinforcing the reliability and coherence of the results. Ongoing work aims to extend this method to selective zinc and cobalt recovery. The flow charts developed in this study aid in selecting appropriate IX-based wastewater treatments. This research aims to recover metals from mining-affected water, reduce waste, and promote metal recycling while enhancing environmental conservation efforts.

Life cycle assessment of the manufacturing and operation of distillation column for eliminating volatile and organic halogen compounds from process wastewater

Distillation serves as the foremost method for commercial-scale separation of fluid mixtures. Widely applied in wastewater treatment, it is the preferred choice for isolating volatile multi-component mixtures into pure substances. Distillation technology offers notable economic benefits due to its easy implementation, high efficiency, productivity, and robust safety features. This study examines the environmental impacts associated with the production and usage of a distillation, specifically in treating pharmaceutical process wastewater containing organic halogen compounds (AOX). The analysis adopts a 'gate-to-gate' approach, with the specified functional unit (FU) set at 1 kg of treated effluent containing no more than 8 ppm of AOX and less than 1000 mg O2/L of Chemical Oxygen Demand (COD). In this work, Life Cycle Assessment (LCA) is conducted using Product Environmental Footprint (PEF) and Recipe 2016 Endpoint (H) V1.06 methodologies, utilizing the SimaPro V9.3.0.3 software in conjunction with the Ecoinvent V3.8 database. Analysis results have shown the emission of 1.11 × 10–2 kg CO2-eq, in which operational and production processes contribute 91.9% and 8.1%, respectively. To mitigate adverse effects, alternative energy sources, i.e., solar, offshore wind, and onshore wind are integrated into the distillation procedure. The substitution of hard coal with solar, offshore wind, and onshore wind energy displays the potential to significantly reduce climate change impact by 64.3%, 62.9%, and 62.8%, respectively.Article HighlightsDistillation process undergoes a thorough life cycle assessment from production to application.Distillation process requires high energy and emits 1.11 × 10–2 kg CO2-eq per functional unit.The operational phase dominates over 90% in three damage categories: human health, ecosystems, and resources.

Study on the Formation and Controllable Movement of Polymer Liquid Columns Based on Dynamic Control of Spatial Electric Field Distribution.

Liquid deformation and motion are very common natural phenomena and of great value in various practical applications. In this study, a dielectric fluid column formation and directional flow phenomenon are presented. Dielectric fluid can grow upward to form a liquid column through a spatial electric field and realize directional and controllable operation of the liquid column by regulating spatial electric field distribution. First, the adjustable electric field space is constructed by connecting the two parallel electrodes to the high-voltage DC power supply. Then, the regional electric field distribution was adjusted by the upper plate graphic and power supply regulation to drive the polymer liquid on the lower plate electrode to form a liquid column at different positions. The results show that the polymer liquid column can be driven by the spatial electric field distributed dynamic control method and that the height and the narrowest width of the liquid column are directly controlled by the voltage. With the experiment conditions that the distance between two parallel electrodes is 5-15 mm, the formation of liquid columns with a height of 5-15 mm can be controlled. In addition, the liquid column can be driven by adjusting the on-states of different conductive regions. When the voltage is 10 kV, the liquid column directional movement speed can reach 1 mm/s. The higher the voltage, the faster the directional movement. The research results can be used as producing polydimethylsiloxane stamp, localized heating and temperature control, fabricating a pulsating heat pipe, and so on.

Singularity Structure Optimization for Hexahedral Mesh Via Dual Operations

Abstract This paper presents an improved method for optimizing the singularity structure of hexahedral meshes using various dual operations. Our approach aims at reducing element distortion by decomposing complex singular nodes into singular curves using high-quality sheet insertion at proper locations. Then, singular curves that meet the topological parallel requirements are paired to perform the semantic column operation, which eliminates the singular curves. Finally, the topological structure is further optimized by collapsing sheets, resulting in a valid hex mesh with a simpler structure. Compared to existing hexahedral mesh simplification methods, our approach can generate higher quality meshes. Experimental results demonstrate the effectiveness of the proposed method.

Differential adsorption of vanadium(V) and tungsten(W) on ion exchange resins: A novel approach for separation and recovery of spent catalyst leachate

Vanadium (V) and tungsten (W) are essential metals for various industries, but separating them is challenging due to the molecular similarity of the two metal ions. A highly concentrated mixed solution of V and W is obtained from spent selective catalytic reduction (SCR) catalysts, but their complete recycling is impeded by the difficulty of separating V and W. In this study, we investigate the ion exchange resin (IXR) technique's effectiveness for separating V and W from the leaching solution of spent catalysts. We evaluated the performance of three IXRs: Lewatit MP800 (strong basic), MP62WS (medium basic), and TP260 (weak acidic) for the separation of V and W ions in the solution. Among these IXRs, MP800 exhibits V and W ion separation behavior at pH 14. It selectively adsorbs W ions, while V ions demonstrate low affinity for adsorption on MP800. The primary mechanism for the adsorption of V and W ions appears to be an ion exchange reaction on the quaternary ammonium group of MP800. Conversely, MP62WS, which adsorbs V and W ions through both ion exchange and chelation mechanisms, does not separate V and W ions effectively when the solution's pH is controlled. The adsorbed W ions on MP800 can be completely regenerated with 2 M NaCl solution through re-ion exchange. We also conducted dynamic column operations using a simulated spent catalyst leaching solution (V = 600 mg/L, W = 4000 mg/L) with MP800 at pH 14. The successful separation of V and W was achieved for up to 15 bed volumes (BV). Finally, we performed V and W separation using an actual spent catalyst leaching solution. MP800 displayed a notably high separation factor (αVW) of 19.59, highlighting its effectiveness in separating V and W.

Adsorptive removal of pharmaceutical contaminants: Accurate description of tailing breakthrough curves

Fixed bed adsorption is a well-established method used to remove various contaminants, including pharmaceuticals, from aqueous solutions. Mathematical modeling plays a pivotal role in analyzing the dynamic behavior of fixed bed adsorption processes. The classic Bohart–Adams model, dating back over a century, is commonly used to describe fixed bed breakthrough curves. However, it encounters difficulties in effectively interpreting tailing breakthrough curves resulting from the slow approach of the fixed bed to saturation. This study presents an enhanced version of the Bohart–Adams model, specifically tailored to address the challenge of analyzing tailing breakthrough data concerning pharmaceutical contaminant adsorption in fixed bed adsorbers. The new formulation incorporates a conceptual steric hindrance model, proposing that the tailing breakthrough behavior is a consequence of a reduction in the rate of adsorption as surface coverage increases. Through rigorous testing, the new model showcased superior performance compared to the original model, accurately describing the tailing breakthrough curves commonly observed with pharmaceutical contaminants such as diclofenac, sulfamethoxazole, and tetracycline. Additionally, comparative analyses of the new model, a mechanistic model, and the empirical Yan model conclusively demonstrated the superiority of the newly proposed approach. The new Bohart–Adams model can be used to precisely predict breakthrough and exhaustion times or optimize column operating conditions.

Process analysis and optimization of high-N2 natural gas liquefaction

The demand for natural gas (NG) is increasing rapidly due to the world energy crisis. Liquefied Natural Gas (LNG) technology is one of the most flexible and reliable supply solutions, which has already been a major research hotpot in energy use. However, NG with high-N2 content lowers the gas calorific value and value of the gas and increases the energy consumption for production and transport. To address this issue, this study established nitrogen removal from the NG process using a single-column cryogenic distillation process based on Aspen HYSYS® in this study. An expanding refrigeration process using N2-CH4 was selected to provide the required cold energy for this plant, and the process power consumption and LNG specific power consumption was used as evaluation indicators. Results from sensitivity analysis showed that by the increase of natural gas feed temperature T1, the distillation column operation pressure Pc, and refrigerant high pressure P3, the LNG specific power consumption also demonstrated an increasing trend. The variables of natural gas inlet pressure P1, the outlet temperature of natural gas from pre-cooler T2, the ratio of return RR, the methane content ZCH4, the temperature of refrigerant after pre-cooler T4 and refrigerant low pressure P5 had a negative impact on the LNG specific power consumption. After conducting an optimization algorithm, the minimum LNG specific power consumption was determined to be 56.17 kJ/mol. Exergy analysis demonstrated that the total exergy destruction was 2076.13 kW. The compressor and expander components accounted for 31.57% and 26.29% of the total exergy losses respectively. This research provides valuable insights into optimizing LNG production processes by mitigating the impact of high nitrogen content, and it contributes to the advancement of LNG technology and energy efficiency in the industry.

A Review on Effects of Operating Parameters in Batch and Column Mode for Adsorption of Methyl Violet Dye

Direct discharge of industrial effluents without treatment into natural sources poses a significant risk to the environment. Dye compounds are toxic and difficult for nature to process, causing serious physiologic harm to all organisms that come into contact with them. Water quality is directly impacted by the presence of methyl violet (MV) dye pigments as it reduces the photosynthetic activity of the streams, so it is crucial to eliminate it. Adsorption is generally accepted as a reliable method for getting rid of dye in wastewater. In most cases, the adsorption process is aided by the mutually beneficial interactions between the adsorbent, the dye, and the adsorption environment. This review highlights current scenarios of MV removal by various low-cost, eco-friendly adsorbents, and their efficiency. The removal of MV is examined in depth in this review paper, which discusses a variety of batch and column adsorption design experiments. Several parameters influence the adsorption process, which is the foundation of all laboratories looking for the best conditions. The primary goal of this review is to provide current information on the most researched affecting factors for batch and column operating modes. Flow rate, dye concentration, and bed height are all parameters in column adsorption investigations and contact time, pH, temperature, particle size, agitation speed, and adsorbent dose were all compiled for batch adsorption investigations and summarized in this review.