Separation Plant Research Articles

Thorium ore dust research applicable to mineral sands industry workers

Historically, radiation exposure to mineral sands workers arose primarily from intake of thorium associated with monazite dust generated in mineral separation plants. Research investigations in the 1990s provided greater insight into the characteristics of inhaled thorium ore dust and bioassay studies inferred that some workers had accumulated significant lung burdens of thorium. Recent changes to biokinetic models have increased the radiation dose assessed to arise from thorium intake, raising questions on the appropriateness of current assumptions used in exposure assessment and feasibility of further bioassay research. Past radiation research undertaken in the Western Australian mineral sands industry is summarised and findings from contemporary research relevant to thorium ore dust exposure, thorium health effects and the associated assessment of internal radiation dose are reviewed and analysed. Radiation exposures in the industry have reduced substantially in the last two decades, however current workplace exposure measurement regimes may not reflect the actual intake of monazite-bearing dusts on an individual basis. Past research indicated that thorium associated with monazite dust is relatively insoluble and avidly retained in the lung. There is a paucity of published research on thorium retention and excretion by mine workers over the last 20 years, however significant advances have been made in the detection of thorium in biospecimens. Improvements in measurement technology should make periodic bioassay measurements feasible for selected long-term workers involved in the mining and processing of naturally occurring radioactive materials. Past worker dose estimates require re-evaluation following recent updates to biokinetic models and long-term follow up of the health of workers chronically exposed to thorium ore dusts is recommended.

Recovery of secondary resource rare earth bearing Indian beach placer garnet and value addition

ABSTRACT The garnets extracted from the coastal region belong to the almandine variety and are available in sizes exceeding + 80#. The size fraction below 80# is discarded at mineral separation plants, resulting in the accumulation of garnet piles, which contribute to air pollution affecting workers. Consequently, any initiative to utilize these finer garnets aligns with transforming waste into wealth. This study focuses on recovering and enhancing rejected-size garnets from the Ramchandi coast in Odisha, India. The extraction process from the beach sand employs wet and dry methods, followed by screening. The findings indicate that the optimal product achieved contains 99.1% garnet, with a recovery rate of 92.8% and a yield of 38.2%, utilizing a combination of spiral concentrators, wet high-intensity magnetic separators, and high-tension separators. The recovered garnets, being of the almandine variety, have a broad spectrum of industrial applications, including the extraction of rare earth elements and the production of industrial precipitated silica. This study aims to develop a process flow sheet for the value addition of waste-sized garnets, targeting the concurrent recovery of rare earth elements such as rare earth hydroxide concentrate, hydrated alumina, precipitated silica, and calcium carbonate. This process seeks to minimize the presence of iron, alumina, and other undesirable impurities in the fine-sized waste garnet, which can be utilized in various commercial applications, such as reinforcing agents in rubber manufacturing, cosmetics, toothpaste, and anti-caking agents in the food industry.

Eco-efficiency analysis and intensification of the monochlorobenzene separation process through vapor recompression strategy

Monochlorobenzene is widely used in producing herbicides, pesticides, and pharmaceuticals and, despite its toxicity and lack of a green substitute, has significant commercial influence. Thus, process intensification can enhance the purification process's sustainability performance. Recently, a double-effect distillation with heat integration (DEDHI) scheme was proposed to intensify an industrial-scale monochlorobenzene separation plant. As a continuation, this work proposes another strategy based on heat integration and vapor recompression (VRHI). A utility plant was considered for realistic outcomes regarding water consumption, CO2 emissions, and utility costs, grouped to represent the process's eco-efficiency. The total annualized cost (TAC) criterion was also contemplated. The comparison showed that DEDHI and VRHI are 84.57 % and 96.21 % more eco-efficient than the conventional process, respectively. The DEDHI design is more economically attractive, reducing TAC by 21.40 % for a 3-year payback period. In contrast, the VRHI scheme is more environmentally friendly, reducing CO2 emissions and water consumption by 73.32 % / 94.08 % (United States / Brazil locations) and 84.87 %, respectively. However, VRHI is only economically attractive for a 10-year payback period, with TAC savings of 18.10 % compared to the conventional process, mainly due to the high capital expenditure for the two-stage compressor and the electricity cost.

Renewable Distillation of Spent Nuclear Fuel

Nuclear waste is one of the most important environmental problems of nuclear power plants. A novel renewable distillation method has been proposed for the direct on-site recycling of spent nuclear fuel and the separation of its valuable components from fissile isotopes, which is especially applicable for reactors using liquid fuels. This dry separation technique can be applied in two single, parallel total-reflux columns with integrated separation stages for chlorinated nuclear waste. According to theoretical calculations, high separation accuracy of the UCl4-NpCl4, PuCl3-UCl3, CmCl3-SmCl3, and EuCl3-CsCl fractions could be achieved using twenty-six separation stages and five total-reflux repetitions, demonstrating the high efficiency of the method proposed. A scheme of the future pyroprocessing separation plant is also presented.

Deep learning based approach for actinidia flower detection and gender assessment

Pollination is critical for crop development, especially those essential for subsistence. This study addresses the pollination challenges faced by Actinidia, a dioecious plant characterized by female and male flowers on separate plants. Despite the high protein content of pollen, the absence of nectar in kiwifruit flowers poses difficulties in attracting pollinators. Consequently, there is a growing interest in using artificial intelligence and robotic solutions to enable pollination even in unfavourable conditions. These robotic solutions must be able to accurately detect flowers and discern their genders for precise pollination operations. Specifically, upon identifying female Actinidia flowers, the robotic system should approach the stigma to release pollen, while male Actinidia flowers should target the anthers to collect pollen. We identified two primary research gaps: (1) the lack of gender-based flower detection methods and (2) the underutilisation of contemporary deep learning models in this domain. To address these gaps, we evaluated the performance of four pretrained models (YOLOv8, YOLOv5, RT-DETR and DETR) in detecting and determining the gender of Actinidia flowers. We outlined a comprehensive methodology and developed a dataset of manually annotated flowers categorized into two classes based on gender. Our evaluation utilised k-fold cross-validation to rigorously test model performance across diverse subsets of the dataset, addressing the limitations of conventional data splitting methods. DETR provided the most balanced overall performance, achieving precision, recall, F1 score and mAP of 89%, 97%, 93% and 94%, respectively, highlighting its robustness in managing complex detection tasks under varying conditions. These findings underscore the potential of deep learning models for effective gender-specific detection of Actinidia flowers, paving the way for advanced robotic pollination systems.

Implementing Antimony Supply and Sustainability Measures via Extraction as a By-Product in Skarn Deposits: The Case of the Chalkidiki Pb-Zn-Au Mines

Antimony is one of the world’s scarcest metals and is listed as a Critical Raw Material (CRM) for the European Union. To meet the increasing demand for metals in a sustainable way, one of the strategies that could be implemented would be the recovery of metals as by-products. This would decrease the amount of hazardous materials filling mining dumps. The present study investigates the potential for producing antimony as a by-product at the Olympias separation plant in Northern Greece. This plant works a skarn mineralization that shows interesting amounts of Sb. Boulangerite (Pb5Sb4S11) reports on Pb concentrate levels reached 8% in the analyzed product. This pre-enrichment is favorable in terms of boulangerite recovery since it can be separated from galena through froth flotation. Boulangerite distribution in the primary ore is quite heterogeneous in terms of the inclusion relationships and grain size. However, a qualitative assessment shows that the current Pb concentrate grain size is too coarse to successfully liberate a good amount of boulangerite. The use of image analysis and textural assessments is pivotal in determining shape factors and crystal size, which is essential for the targeting of flotation parameters during separation. The extraction of antimony as a by-product is possible through a two-step process; namely, (i) the preliminary concentration of boulangerite, followed by (ii) the hydrometallurgical extraction of the antimony from the boulangerite concentrate. The Olympias enrichment plant could therefore set a positive example by promoting the benefits of targeted Sb extraction as a by-product within similar sulfide deposits within the European territory.

Направления совершенствования сероочистки, осушки и переработки природного газа

The results of the work of the staff of the Department of “Chemical Technology of Oil and Gas Refining” of Astrakhan State Technical University in the field of separation of three-phase reservoir mixture, increasing the efficiency of desulfurization, improving the process of drying gas and the production of continuous hydrocarbons – raw materials for petrochemistry. The influence of the quality of raw materials entering processing on the formation of deposits in technological equipment has been studied. Reconstruction of the inlet and three-phase separators of high-pressure reservoir mixture separation plants by installing a vibration damper and a depulsor on the reservoir mixture supply line to the installation, as well as reconstruction of the input of raw materials into the separator of the installation. The use of the KPG-200 defoamer and the KPG-200 AV antifoamer made it possible to reduce the consumption rate of defoaming reagents several times in gas purification plants from acidic components. The influence of various impurities on the foaming of working amine solutions (mechanical impurities, coal dust, products of thermal destruction of amine, thermostable salts, corrosion inhibitors) has been determined. It was revealed that the products of thermal degradation of amine have the greatest effect at concentrations above 3% by weight. A method for reducing the content of mechanical impurities in a solution of diethanolamine in a constant magnetic field has been developed and introduced into an industrial desulfurization plant. The filtration efficiency increases 2.6 times, the foam height is halved, and the foam stability is quadrupled. At the same time, the activity of the defoamer increases by 1.7 times. The mathematical dependence of the height of the protective layer of aluminum oxide in an adsorber with zeolite on impurities of diethanolamine has been experimentally found. The effectiveness of the developed improved distribution ring device is shown, the use of which makes it possible to practically eliminate dead zones in the zeolite layer and thereby increase the efficiency of the adsorption process and increase the inter-regeneration period on the drying unit. Studies of the catalytic pyrolysis of the butane fraction using CVM-type pentasils modified with the introduction of chromium can reduce the process temperature compared with the thermal decomposition of raw materials by more than one hundred degrees 100 °C.

Noise and frequency propagation in natural stone processing plants

In this study, 510 noise measurements recorded in eight natural stone processing plants operating in Sivas City, Turkey were evaluated and the noise levels and dominant frequency bands of 11 different processing machines used in these plants were determined. The daily equivalent noise level of all natural stone processing plants was around or above the exposure limit value (87 dBA) specified in relevant regulations. Considering the machines and plant environment, the frequency ranges for the highest noise levels were mostly between 630 Hz - 5000 Hz, centering around 3150 Hz. Variations in the noise level of the processing machines in separate plants where similar processes were carried out was primarily related to the plant size and machine layout, the number of machines operating simultaneously and the type of natural stone processed. While the difference between the noise levels of gangsaws, bridge cutting, ST cutting, head/side cutting, trimming, cement filling, slab polishing, narrow polishing, chamfering and splitting machines were statistically significant, aging machines generated similar noise levels.

A Flowering Morphological Investigation, Fruit Fatty Acids, and Mineral Elements Dynamic Changes of Idesia polycarpa Maxim.

Idesia polycarpa Maxim is a high-value species of fruit oil with edible, abundant linoleic acid and polyphenols. Idesia polycarpa is described as a dioecious species, and the flowers are male; female and bisexual flowers are produced on separate plants. In order to explore the flower types of Idesia polycarpa, the morphology of its flowers and inflorescence were investigated in this study. The flower and inflorescence types, the diameter, and the flowering sequencing in male and female inflorescence were determined. We also detected the length, width, and fresh weight of leaves, shoots, and female inflorescence, as well as the length and fresh weight of the petiole during the development. Additionally, we compared the length, width, the length/width ratio, and the flowering density between 5- and 7-year-old female trees. The phenological period observation of Idesia polycarpa showed that the development process can be roughly divided into 12 stages, including bud burst, leaf expansion, inflorescence growth, initial flowering, full flowering, flower decline, initial fruiting, fruit enlargement, fruit color change, fruit ripening, post-ripening of fruit, and leaf fall periods. Furthermore, four elites' fruit determined the oil content and the composition of fatty acid content during the development. The dynamic of fatty acids contents, the palrnitic acid, palmitoleic acid, stearic acid, oleic acid, and linolenic acid contents were detected during the fruit development of four elites. Moreover, the mineral elements content of fruit of four elites during development were determined. The patterns of vegetative and reproductive growth in young dioecious trees of Idesia polycarpa provided the theoretical basis for artificial pruning and training.

Physiological trait coordination and variability across and within three Pinus species.

Studies have explored how traits separate plants ecologically and the trade-offs that underpin this separation. However, uncertainty remains as to the taxonomic scale at which traits can predictably separate species. We studied how physiological traits separated three Pinus (Pinus banksiana, Pinus resinosa, and Pinus strobus) species across three sites. We collected traits from four common leaf and branch measurements (light-response curves, CO2-response curves, pressure-volume curves, and hydraulic vulnerability curves) across each species and site. While common, these measurements are not typically measured together due to logistical constraints. Few traits varied across species and sites as expected given the ecological preferences of the species and environmental site characteristics. Some trait trade-offs present at broad taxonomic scales were observed across the three species, but most were absent within species. Certain trade-offs contrasted expectations observed at broader scales but followed expectations given the species' ecological preferences. We emphasize the need to both clarify why certain traits are being studied, as variation in unexpected but ecologically meaningful ways often occurs and certain traits might not vary substantially within a given lineage (e.g. hydraulic vulnerability in Pinus), highlighting the role a trait selection in trait ecology.

Failure analysis of a separator under various thermal loading: A numerical study

In the present study, Computational Fluid Dynamics (CFD) simulations were carried out on a separator subjected to three different fire scenarios: pool fire, jet fire and fireballs. The empirical models applicable to such plants are not developed and conventional radiation models leads to an overestimation of the heat flux and safety distances. Therefore an alternative tool like CFD along with empirical models is used to model the potential scenarios mentioned above in a model oil and gas separator plant. The developed model were validated by comparing literature data on the flame length, maximum flame temperature and its location above pan surface in case of pool fire and comparing them with literature data. It is found that in case of flame length the deviation from literature data was about 10% and less than 5% for the maximum flame temperature. For jet fire the average surface temperature was 561 K while this value is 423 K in case of pool fire and 317 K for fireballs. When it comes to the radiative flux, an average value of 29 kW/m2 is found for jet fires while this value was only 14 kW/m2 for pool fire and 23 kW/m2 for fireballs. The thermal loads on the separator vessel due to above fire scenarios were also calculated. The obtained value of thermal stresses were around 285 MPa and 600 MPa for pool and jet fires respectively. Thus it can be concluded that from safety point of view jet fires are the most critical one. The results obtained form simulations were also compared with that of data from empirical models.

Valorization of the complex organic waste in municipal solid wastes through the combination of hydrothermal carbonization and anaerobic digestion

Municipal Solid Wastes (MSW) consist of the valorizable inorganic fraction, i.e., Refuse Derived Fuel, and the organic fraction which also can be valorized. However, the separated organic fraction, which is known as Complex Organic Waste (COW), contains traces of glass, plastics, non-ferrous metals, and stones. Thus, the aim of this work was to determine the value of the COW that comes from a MSW separation plant through the combination of Hydrothermal Carbonization (HTC) and Anaerobic Digestion (AD) for the production of biofuels. COWs were conditioned to undergo HTC for 1 h at 180 °C and 190 °C. HTC liquid was used as a substrate operating an Anaerobic Hybrid Reactor (AHR) in continuous mode with 5 gCOD/Ld at 35 ± 2 °C. The hydrochar contained on average (dry matter): (180 °C) 30.44 % carbon and 15.47 MJ/kg and (190 °C) 40.44 % carbon and 17.60 MJ/kg. The AHR removed more than 93 % (COD) reaching 0.34 LCH4 at STP/gCODrem, and no inhibitory effects were observed. The coupling of HTC with AD at low temperatures for short times turned out to be a promising alternative for the valorization of COW, i.e., it produced 10,888 MJ (94 % HTC and 6 % AD) per metric ton of COW.

Advancing Water Deoiling Efficiency in Petroleum Production: A Comprehensive Case Study of Hybrid Flotation Technology Integration

_ The efficient management of increasing water cuts in oil fields is paramount for sustaining profitability and minimizing environmental impact. This article presents a comprehensive case study conducted by Saudi Aramco, focusing on the integration of hybrid flotation technology into a gravity water/oil separator (WOSEP) to enhance deoiling efficiency and reduce operational costs and carbon emissions. The retrofit involved merging enhanced gravity separation with induced gas flotation (IGF) within the same vessel, resulting in significant improvements in deoiling capacity, outlet oil-in-water content reduction, and operational efficiency. Detailed insights into the design, operation, and performance of hybrid flotation systems are provided, offering valuable guidance for similar initiatives in the petroleum industry. Introduction Petroleum production facilities face escalating challenges with increasing water-production rates during crude-oil extraction, particularly in waterflooding operations for secondary oil recovery. This trend not only escalates operational costs but also intensifies environmental concerns, particularly regarding energy consumption and carbon emissions associated with water-handling processes. In response to these challenges, Saudi Aramco embarked on a pioneering initiative to enhance water-deoiling efficiency by integrating hybrid flotation technology into a conventional gravity WOSEP. This case study presents a comprehensive analysis of the design, implementation, and outcomes of this transformative project, offering valuable insights for the broader petroleum industry. Methodology The upgrade process commenced with an assessment of the existing WOSEP system and its operational challenges. Recognizing the impending capacity constraints and escalating oil-in-water content, Saudi Aramco’s engineering team opted for a holistic approach that combined enhanced gravity separation with IGF within the same vessel. The retrofit involved reconfiguring the internal components of the WOSEP to accommodate the hybrid flotation system, including the installation of advanced plate-pack internals for gravity separation and the integration of IGF cells for additional oil removal. Rigorous testing and optimization procedures were conducted to ensure seamless integration and optimal performance of the hybrid system. Gas/Oil Separation Plant Process Description In a typical gas/oil separation plant, the initial phase involves the extraction of crude oil, associated gas, and produced water from wells via a production manifold. These constituents are then directed to a three-phase separator, also known as a high-pressure production trap (HPPT). In the HPPT, free water droplets are separated from the oil through gravity separation, aided by demulsifier injection at the production header. The separated free water is discharged to a WOSEP, typically a gravity separator, for deoiling.

Reformer + Membrane separator plant for decarbonized hydrogen production from Biogas/Biomethane: An experimental study combined to energy efficiency and exergy analyses

Nowadays, the world energy production is still based on the exploitation of fossil fuels, mainly oil, coal, and natural gas, responsible for large greenhouse emissions in the environment. According to the measures proposed by the European Green Deal to meet the carbon neutrality by 2050, the decarbonisation of the global energy production processes represents a top priority. Hydrogen represents a carbon-free energy carrier, useful to drive the society toward a decarbonized-economy. The novelty of this work is represented by the experimental generation of clean hydrogen by a two stages plant constituted of a biogas/biomethane steam reformer and a Pd-Ag membrane separator, meanwhile applying on this simple case the methodology of the exergy analysis, identifying the main losses and suggesting improvements. Hence, it deals with the exergy analysis of the whole system with the process intensification operated by the membrane separator adopted instead of using several stages to separate/purify hydrogen − as conventionally done after the reforming stage (two water gas shift reactors, high and low temperature, followed by a pressure swing adsorption stage) − with the objective of recovering decarbonized hydrogen coming from the biogas/biomethane steam reformer, meeting the European targets indicated by the Clean Hydrogen Alliance. This approach allowed to understand the amount of irreversibilities present in such a system as well as how the thermal efficiency may be influenced by a number of parameters, constituting globally a baseline for the scaling up of this process technology from lab to bench/pilot scale. The best results of this work highlight that the utilization of biomethane in the feed stream to generate hydrogen resulted to be a better choice than biogas in terms of thermal efficiency (based on the lower heating value) of the whole system, equal to 73 % at 773 K, while the highest percentage of exergy destruction was concentrated in the condensation stage, with values varying between 76 % and 93 %, depending on the feed stream typology. The two stages system was able to meet the “decarbonized hydrogen production target 2027”, with a hydrogen recovery of 90 % and a purity of 99.9999 %. Last but not least, the overall exergy destroyed efficiency of the overall system in the two analyzed cases was 92 % (biomethane feed stream) and 88 % (biogas feed stream), respectively.

REMOVAL OF LEAD IONS BY GREEN SYNTHESIZED SILVER NANOPARTICLES USING AQUEOUS EXTRACTS OF PROSOPIS JULIFLORA AND MENTHA PIPERITA L. LEAVES

Heavy metal compounds are commonly used as required industrial materials. Heavy metal ions are known to possess poisonous properties. Lead (II) ion is one of them; it is more toxic and carcinogenic. The contamination of water with Pb (II) may lead to kill people who drink it, in addition to harmful effects on plants and animals. Therefore, Pb (II) ions must be removed from the polluted water. In this work, an eco-friendly method was employed to synthesize silver nanoparticles (AgNPs) from silver nitrate and two separate plant extracts; leaves of Prosopis Juliflora and Mentha Piperita L. AgNPs were used to remove Pb (II) ions from aqueous solutions through the adsorption process. The synthesized AgNPs were identified by ultraviolet- visible (UV-Vis), Fourier-transform infrared (FTIR), transmission electron microscope (TEM), scanning electron microscope (SEM), and energy-dispersive X-ray spectroscopy (EDS) analysis. The diameters of formation nanoparticles were within the range of 8.06–11.5 and 8.02- 11.5 nm of AgNPs from Prosopis Juliflora, and AgNPs from Mentha Piperita L. extracts, respectively. During the adsorption process, the influence of adsorbent dose, Pb (II) ion concentration, and contact time in removing were studied at constant temperature and constant pH.

Współczynnik erozji gleby przy użyciu wielospektralnych wskaźników roślinności: Przykład zlewni rzeki Sarayardere (wschodnie Rodopy, Bułgaria)Wpływ zmian klimatu na środowisko zbudowane

Land cover/land use is one of the main factors influencing the development of soil erosion. It has been included in the calculation and modelling of erosion and sediment transport in many studies. In the current research NDVI (normalized difference vegetation index) and NDRE (normalized difference red edge index) are used for quantifying the cover management factor (C-factor). They are calculated on the base of Sentinel 2 multispectral images. Taking into account the vegetation phenology two time points were analyzed: end of May - June – active vegetation and September (beginning of October) – late vegetation. The changes in the values of the indices were considered for 2018, 2021 and 2022. The study area is the watershed of the river Sarayardere, located in the southern part of Bulgaria. This is a hilly to low-mountain area, prone to erosion due to rare vegetation, high slope gradients and a relatively long dry period followed by intensive rainfall. The calculated values of the C-factor are indicators for higher susceptibility to erosion in September than it is in June. The spatial distribution of the C-factor shows different patterns. The results, received on the base of the image of September 2021, show increasing the areas with C-factor < 0.1 and these ones > 0.5, in comparison with the results of September 2018. C-factor values calculated on the image of October 2022 indicate the highest susceptibility to erosion. Using NDRE instead NDVI results in slightly higher values of the C-factor. The advantage of the NDRE index is that it provides information on the content of chlorophyll in the vegetation during the end of the vegetation period and allows a more accurate assessment of the state of the separate plants, regarding the determination of diseased or damaged plants. In addition to the vegetation indices, an expert evaluation of the state of vegetation was done. The results of the current study show that the watershed of the river Sarayardere is in a relatively good condition regarding the development of erosion processes. The attention should be directed to the possible increase of erosion on deforested slopes and the availability of loose materials, in case of intense rainfall.

ПРОБЛЕМА ПОВЫШЕНИЯ НАДЕЖНОСТИ МАШИН И ОБОРУДОВАНИЯ

The basis for a satisfactory level of operability of modern machines and equipment of domestic production was and remains the engineering and technical service of equipment and the "Planned preventive maintenance and repair system of machines in agriculture." Timely implementation of mechanized processes and work with low reliability of agricultural machinery requires an increase in the level of reliability and serviceability of the fleet of machines and equipment. (Research purpose) The research purpose is increasing the operational reliability of modern agricultural machinery based on the development and implementation of proprietary technical service. (Materials and methods) Materials obtained as a result of the author's own research and data on the reliability of domestic machinery and equipment from open sources were used in the research. The following methods were applied: comparative assessments, analysis and synthesis of the results of a survey of the operational reliability of agricultural machinery and equipment in real-world operation, the effectiveness of using various forms and methods of organizing their production and technical service. (Results and discussion) It was determined that an increase in the level of operability and reliability of modern domestic equipment can be ensured only with a significant improvement in the quality of manufacturing machinery and equipment and with the direct participation of the equipment manufacturer in technical service based on the proprietary method of technical service. It was noted that the organization of corporate technical service is possible only when creating a corporate production and technological system of mechanical engineering. The solution of this problem by the forces and means of existing separate equipment manufacturing plants is not possible. (Conclusions) To improve the reliability of modern domestic technology, it is necessary to reorganize the existing system of separate manufacturing plants, create large machine-building firms and branded technical service centers.

Analysis of multi-objective optimization applied to the simulation of a natural gas separation plant

This study concentrated on simulating and optimizing a natural gas separation plant using Unisim Design® software. The optimization procedure aimed to maximize gas production and the higher-molecular-weight hydrocarbons (yC5+) in the produced gas. The maximum water dew point of −45 °C of the produced gas was specified. The Nelder Mead/Weight Sum Method (NM/WSM) algorithm was employed in Python to optimize five decision variables involving the temperature and pressure of the main process streams. Results indicated that the relative deviations below 1%, compared to reference values, were obtained for the main process variables. The multi-objective optimization (MOO) results showed an increase in gas production of up to 5.58% (maximum value of 62,736.10 kg/h) and a rise in the molar fraction of yC5+ by up to 32.2% compared to the reference values. However, it was noted that maximizing gas production indirectly maximizes the yC5+, with only a single decision variable differing in the optimal direction, represented by the intermediate temperature of one compression stage. A Pareto curve was built to display the range of optimal solutions, showing variations of 0.035% in optimal gas production and 0.11% in yC5+. Furthermore, various simulation scenarios were optimized with different thermodynamic conditions at the unit's inlet. In all cases, the optimization resulted in an average gain of 1.57% in gas production regarding the reference (non-optimal case).

Inferential control strategies using neural soft sensor in a high purity distillation column

High-purity distillation columns are processes in which you want to minimally increase the purity of a key component by separation. These processes are sensitive to disturbances, where small changes in the feed flowrate stream cause drastic changes in product compositions. Furthermore, when one wants to apply traditional control and optimization techniques to these processes, some difficulties have to be faced: the process is generally non-linear and has a long response time, there are many immeasurable disturbances, it is difficult to keep the process in steady-state, and the bottom and top compositions are highly coupled. Therefore, this paper presents a methodology for the development of soft sensors (SS), here in applied to an industrial 1,2-Dichloroethane separation plant. The process was simulated and validated with real data from the industrial plant. In the step second an algorithm based on multivariate statistics was developed for the selection of inputs SS variables. The configuration for training multilayer artificial neural network (ANN's) was optimize, accounting for the ANN's prediction capacity of responses and the rejection of disturbances inserted in the process. Thereafter, a temperature control was implemented to maintain the impurity compositions within specifications but failed due to the small temperature variations in the high purity column. To overcome these difficulty three inferential control strategies (impurity composition estimated by the SS) were implemented: a classic feedback control, a cascade control, and a ratio-cascade control. All control strategies acted to minimize the process disturbances effects. However, the inferential ratio-cascade control shown to be the most robust, because of the lowest integral error criteria value and percentage overshoot.

Introducing and performance evaluation of a novel Multi-Generation process for producing Power, fresh Water, oxygen and nitrogen integrated with liquefied natural gas regasification and carbon dioxide removal process

The objective of this paper is to develop and evaluate a new integrated multigenerational system comprised of cryogenic air separation, hydrate-based desalination, combined cycle and oxyfuel power plants, carbon dioxide amine absorption, and transcritical carbon dioxide power cycle, employing liquefied natural gas cold energy. This integrated multi-generation system, applicable for liquefied natural gas importer terminals with access to seawater, produces approximately 2,533 MW net output power and 1,985 kg/h fresh water. In addition, this integrated multi-generation process produces 16,735,861 kg/h high-purity liquid oxygen (100 mol%), 4,773,633 kg/h liquid nitrogen with 99.71 mol% purity, more than 31,724,465 kg/h high-purity gaseous nitrogen (99.9 mol%), and 90,903,230 kg/h low-purity gaseous nitrogen (83.38 mol%). About 5907.3 MW of produced power is generated by liquefied natural gas expander. The performance of this system is evaluated by energetic methods. The results of energy analysis show the specific energy consumptions of the air separation products are 0.551 kW/kg and 1.93 kW/kg for liquid oxygen and nitrogen, respectively. Moreover, in the hydrate-based desalination subsystem, the specific energy consumption is 0.5 kW/m3 for produced pure water. The combined cycle power plant includes two gas turbines, three steam turbines, and a three-pressure level heat recovery steam generation. The thermal efficiencies of gas turbine cycles (Bryton), steam turbine cycles (Rankine) and combined power cycles are 26.3 %, 29.6 %, and 36.2 %, respectively. The flue gases from power plants enter the carbon dioxide amine absorption subsystem. The separated carbon dioxide is used as a working fluid to produce 372.1 MW power in transcritical carbon dioxide cycle. The results of energy analysis for carbon dioxide amine absorption subsystem show that the specific energy consumption, the ratio of captured carbon dioxide per unit mass of liquefied natural gas and the carbon dioxide removal efficiency are 6.60 kW/kg, 33.91 kg/tone, and 90.06 %, respectively. Approximately 2,905,000 kg/h of liquid carbon dioxide is obtained as the byproduct of this multi-generation process. Additionally, sensitivity analysis is conducted to determine key parameters influencing the main energetic indexes. Finally, the amount of attainable regasified natural gas reaches 257,523 tone/h by applying this multi-generation system with total 86 % energy efficiency.