Distillation Unit Research Articles

IMPROVEMENT OF FUEL OIL VACUUM RECTIFICATION PROCESS

Primary oil distillation units form the basis of all oil refineries; the quality and yield of the resulting fuel components, as well as raw materials for secondary and other oil refining processes, depend on their operation. Many Atmospheric Vacuum Tubing (AVT) plants are characterized by low recovery of heavy vacuum gas oil. Insufficient selection of heavy vacuum gas oil production leads to a high yield of vacuum residue - tar, which reduces the volume of oil refining in general.The article analyzes ways to improve the process of vacuum distillation of fuel oil at CDU/AVT primary oil distillation units, and searches for ways to increase the efficiency of already built CDU/AVT plants by increasing the selection of heavy vacuum gas oil. Options for technical re-equipment are presented to improve the technical and economic efficiency of atmospheric-vacuum tubing plants with the maximum use of the best achievements in this area and the maximum possible selection of heavy vacuum gas oil at existing primary oil distillation units. The schemes of intensification during vacuum distillation by the method of fractionation of hydrocarbon raw materials by exposing it to electromagnetic oscillations, by the method of gas oil cryolysis. Besides, the schemes of fuel oil distillation according to a two-column scheme and the rectification of half-tar in an additional vacuum column are considered. The main features in the technological design of the process, as well as the features of installation operation, are noted. The proposed schemes make it possible to obtain high-quality feedstock for catalytic cracking and hydrocracking with a high recovery of vacuum gas oil.

Corrosion in Crude Oil Distillation Units (CDUs) and a Study of Reducing Its Rates by Changing Chemical Injection Sites

The injection of chemicals is one of the most important treatment steps used to reduce the effect of corrosion factors in crude oil distillation units in oil refineries. As a result of the availability of suitable conditions for the formation of the main corrosion agents, namely acids (HCI, H2S). It has become necessary to neutralize the effect of these factors in distillation units and towers by changing the sites of adding chemicals, where oil refineries use anti_ corrosion film and caustic soda (NaOH) as well as neutral amine to control and limit the effect of chloride ion, iron rates, salts and the (PH) values. As a result, the research paper is interested in developing a study of adding and changing chemical injection areas (points) of adding chemicals, especially (caustic soda and neutralizer amine) at different specific points, and as it is well known, crude oil passes through a number of different heat exchangers to raise its temperature in preparation for refining. It was found that changing the addition of the neutral amine in the striper tower area of the kerosene section (drops that are returned to the main refinery tower) has a significant effect in controlling the stabilization of pH values between (5.5-6.5) and reducing the iron ion concentration at a rate of (1% ppm), While the injection of caustic soda depends on the temperatures of the crude oil, so it is changed into two lines. The first is before the heat exchangers, that is, when the temperature of the crude oil is (20-35) c̊, and the second line is after the crude oil reaches the temperature (65-90) c̊, it has a significant effect in reducing the concentration of the chloride ion at a rate of (1-5 ppm) present in the form of chloride salts dissolved in the crude oil.

Carbon nanoparticle facilitated functional pyramid solar distillation unit for wastewater treatment

This paper proposes an efficient treatment of reverse osmosis reject (RO reject) and kitchen wastewater (KWW) in a locally developed single-stage functional pyramid solar distillation unit (FPSDU). The working mechanism of the designed and developed solar distillation unit, its specifications, treated water characteristics, novelty over conventional units, and economic analysis have been discussed in detail. The concept of coating glass beads is attempted for its functional application in solar still for generating photothermal heat. Carbon nanomaterials (CNP) coated glass beads were used as a heat storage medium. FPSDU produced approximately 6003 mL/m2day of treated water for KWW and 5868 mL/m2day for RO reject wastewater vis-a-vis output of 3000 mL/m2day for conventional solar distillation unit with an input of 7000 mL/m2day of wastewater in each case. This demonstrates that the FPSDU shows an improved performance than conventional distillation units, recovering about 85% of the treated water from KWW and RO reject wastewater as compared to 43% for conventional distillation units. The basin surface showed no signs of corrosion and the coating remained stable even after multiple cycles. The treated water met the criteria as per Indian standards, free with microbial contamination and can be used for different non-potable uses. Findings of the current research supports the improved effectiveness of FPSDU for RO reject and KWW treatment with immobilized carbon nanoparticles.

Energy, environmental, and economic analysis of a new configuration multi-stage flash distillation unit coupled with steam power plant

This study focuses on the utilization of three waste streams from a power plant for the provision of cooling water and required steam for heating purposes in a multi-stage flash desalination (MSF) unit. The mathematical model for a new configuration of MSF desalination is presented. In conventional MSF desalination unit, a stream of salt water is used for desalination and system coolant. A new structure for the desired desalination process, proportional to the salt concentration of the feed streams and based-on un-mixing of the target streams has been proposed. The proposed system required 18 m2 of cross-sectional area and also 87 m2/(kg/s) of specific heat transfer area in the power plant with seven stages. The optimal value of top brine temperature (TBT) has 110 °C and the capacity of the proposed MSF desalination unit is 92.43 m3 of fresh water/day. The gain output ratio (GOR), energy intensity and water cost of the system are calculated to be 3.12, 706.8 kJ/kg, and 0.69 $/m3, respectively. By application of proposed MSF desalination, the annual emission of 1167.5 tons CO2 into the atmosphere can be obviated and the cost savings resulting from equal fuel consumption amount to $116,315.5 per year.

Thermal Effect on Algae, Biofilm and Their Composition Towards Membrane Distillation Unit: A Mini-review.

Membrane distillation (MD) has lower operating temperature and potential to recycle waste heat for desalination which catches much attention of the researchers in the recent years. However, the biofouling is still a challenging hurdle to be overcome for such applications. The microbial growth rate, secretion and biofilm formation are sensitive to heat. Membrane distillation is a thermally driven separation, so the increase of temperature in the seawater feed could influence the extent of biofouling on the unit parts. In this review, we present the effect of temperature on algal growth, the range of temperature the microbes, marine algae and planktons able to survive and the changes to those planktons once exceed the critical temperature. Thermal effect on the biofilm, its composition and properties are discussed as well, with association of the biofilm secreting microbes, but the study related to membrane distillation unit seems to be lacking and MD biofouling factors are not fully understood. Characterization of the algae, biofilm and EPS that govern biofouling are discussed. This information not only will help in designing future studies to fill up the knowledge gaps in biofouling of membrane distillation, but also to some extent, assist in pointing out possible fouling factors and predicting the degree of biofouling in the membrane distillation unit.

Prioritisation of operations during emergency shutdown of a crude distillation unit by interval-valued intuitionistic fuzzy analytic hierarchy process

A very reliable control system for offering a safety layer in emergency scenarios is an emergency shutdown system, or ESD system. It aids in preventing crises from having disastrous effects on the economy, the environment or business operations. In any plant, emergency shutdown systems reduce the risk of harm to the working population, the environment or equipment damage by guarding against leaks, hydrocarbon escapes, fire outbreaks and explosions. The ESD system halts process activity in an emergency, ensures that the hazard is isolated and does not worsen. It is essential that there is a clearly defined emergency procedure in place when a facility needs to be shut down in an emergency. When preparing an emergency procedure for use in an emergency, it is crucial to prioritise the operations. The factory uses an Interval-valued Intuitionistic Fuzzy Analytical Hierarchy Process (IVIFAHP) to prioritise activities in emergency situations. It is possible to design emergency shutdown systems using the aforementioned order of operations. It is possible to properly set up safety measures using the multi-criteria decision-making approach (MCDM). The Analytical Hierarchy Process (AHP) compares variables without taking measurement scales or units into consideration, which is a distinct benefit. The AHP’s handling of ambiguity, uncertainty and imprecise data is improved by the IVIFAHP.

Modulation of struvite composition in full-scale nutrient recovery system using source-separated urine.

Using urine collected from a public restroom at a highway rest stop in Northern California, a full-scale nutrient recovery system involving a two-part system consisting of urine distillation followed by the precipitation of struvite crystals was characterized. The study examined the effects of different operational parameters of the coupled ammonium distillation and struvite process (CADSP) on the composition of struvite crystals and the overall nutrient recovery rates. System inputs that were investigated included the feed:steam (F:S), alkalinity source, and urinary pH. Overall, the findings demonstrate that the composition of the struvite produced can be varied by adjusting the preceding distillation unit process. Low F:S distillation operations result in high ammonium distillation rates which coincided with increased formation of magnesium potassium phosphate (MPP) while higher F:S operations led to conditions favorable to magnesium ammonium phosphate (MAP) precipitation. Therefore, low energy distillation operations (high F:S) are more conducive to MAP formation and high phosphorus recovery rates while high energy operations (Iow F:S) are more conducive to MPP formation. Sodium-based alkalinity sources should also be avoided in instances of low ammonium concentrations in the struvite precipitation tank to minimize the co-precipitation of magnesium sodium phosphate (MSP) with MPP.

Optimization and design analysis of multistage water gap membrane distillation for cost-effective desalination

This study presents an analysis of a detailed theoretical model and optimization of a novel large-scale multistage water gap membrane distillation (WGMD) unit with an internal gap propeller. The developed mathematical model is coupled with a differential evolution (DE) algorithm for the optimization of the gap design variables and the system operating parameters. The gap design variables, including the propeller thickness, speed, location, thermal conductivity, and diameter, are optimized and used in multi-stage analysis for investigating the effect of different operating parameters such as feed temperature, feed flowrate, and coolant temperature. The optimized results indicate that a thinner propeller, a larger propeller diameter, a higher propeller revolution, and higher propeller thermal conductivity enhance the system productivity, the gained output ratio (GOR), and the product cost. The parallel arrangement shows a higher production rate of 1738 L/h, a higher GOR of 0.5314, and a lower freshwater cost of $1.027/m3. A mean improvement of about 28.9 %, 12.4 %, 2.4 %, and 28.9 % in productivity, GOR, cost, and recovery ratio (RR), respectively, is registered by the optimization model when compared to no optimization. Additionally, operating the system at the ambient cooling stream improves the system's GOR but decreases its productivity. Furthermore, low feed salinity with a cooling energy attained superior productivity, GOR, recovery ratio, and freshwater cost in comparison to high feed salinity with an ambient cooling stream.

Pre‐deacidification of hazelnut oil by short‐path distillation: Changes in 3‐chloropropane‐1,2‐diol esters, glycidyl esters, free fatty acids, tocopherols, and diglycerides

AbstractPerforming pre‐deacidification using short‐path distillation at high temperatures and vacuum levels is a general application for fats and oils with high free fatty acids (FFA) to reduce their FFA contents to reasonable levels before steam distillation or neutralization. This study aims to determine the changes in 3‐chloropropane‐1,2‐diol esters (3‐MCPDE), glycidyl esters (GE), and diglyceride (DG) as well as the losses in tocopherols during this process. A bleached hazelnut oil having 12.10% FFA content was distilled using a molecular distillation unit at 200 °C, 220 °C, and 240°C temperatures and 0.25, 0.5, 1, and 2 mbar absolute pressures. The target was to reduce FFA content to less than 2% with minimum tocopherol loss. The results showed that considerable removals in FFA and GE contents were achieved by increasing the temperature and vacuum, while fewer decreases were detected in 3‐MCPDE and DG concentrations. Tocopherols were dramatically decreased by temperature rising, therefore, the lowest temperature (200°C) and absolute pressures (0.25–0.5 mbar) might be suitable for pre‐deacidification of hazelnut oil, where the distilled oil contained 1.78%–1.90% FFA, 243.11–286.76 mg kg–1 tocopherol, 0.50–0.55 mg kg–1 3‐MCPDE, 0.03–0.05 mg kg–1 GE and 4.00–4.22 mg kg–1 DG.Practical Application: Vegetable oils with high free fatty acid (FFA) contents are generally subjected to physical refining to avoid considerable refining loss. However, high temperatures applied to vegetable oils during physical refining result in the formation of 3‐MCPDE&GE, and the loss of some nutrients, such as tocopherols. These adverse effects can be reduced through application of lower temperatures and shorter time during physical refining. This can be applied after the FFA contents of the oils are decreased to reasonable levels (less than 2%) by distillation (pre‐deacidification) before the deodorization. Although this technique has been implemented in many plants, there is almost no information on the effects of applied conditions on 3‐MCPDE and GE and some other minor constituents. This manuscript explains the changes in these compounds during the pre‐deacidification of hazelnut oil by molecular distillation. Suitable distillation conditions were also suggested, which would be very useful for industrial refining plants.

Thermodynamic assessment of crude distillation units: case studies of Nigeria refineries

Thermodynamic assessment of crude distillation units: case studies of Nigeria refineries

Proposal and energy/exergy/economic analyses of a smart heat recovery for distillation tower of the Naphtha Hydrotreating Unit of the Petrochemical Plant; designing a low-carbon plant

Abstract This paper suggests a novel framework to retrieve the squandered heat of the Naphtha Hydrotreating Unit of the petrochemical plants. In this idea, the distillation tower’s output of the hydrotreating naphtha unit of the plant is employed as the working fluid to run an organic Rankine cycle with benzene. The procedure is evaluated comprehensively from energy, economic and exergetic point of view using Aspen Haysys software. An advanced case study, including sensitivity analysis, is provided for the Bouali petrochemical plant in Iran to realistically indicate the performance of the suggested configuration. The air cooler in the distillation unit of the aforementioned plant removes (squanders) about 3418 kW of energy, which an organic Rankine cycle can recover. Based on the findings, the exergetic and thermal efficiency of the suggested cycle is 82.53 % and 13.28 %, respectively, with a 1,3620kWh/day rate of energy production. According to the exergetic analysis, the ORC turbine has the highest exergy destruction rate of about 178.76 kW. Also, using the distillation tower squander heat as the heat source to the organic Rankine cycle leads to the least exergy destruction rate. Besides, the output exergy ratio of the whole integrated system to its input is 0.907. The suggested integrated system reduces the total energy consumption from 0.4 to 0.29 GJE/tonFeed with a total investment cost of 11.97 M$, in which the turbines have the highest portion of about 11.2 M$. Hence, the suggested plan’s total income is around 31.94 M$/year.

ИССЛЕДОВАНИЕ ФИЗИКО-ХИМИЧЕСКИХ ПОКАЗАТЕЛЕЙ ВИННОГО ДИСТИЛЛЯТА И РЕКТИФИКАТА ИЗ ВИНОГРАДА ЦВЕТОЧНЫЙ

The results of study of physico- chemical parameters of wine distillate and rectification from white grapes of Cvetochniy variety of ARRIV&W’s breeding are presented. The process of distilling wine material was carried out in two stages. Primary distillation to obtain raw alcohol was carried out on a distiller, and secondary distillation to obtain rectified alcohol was carried out on a small distillation unit with electric heating. It was found that during the primary distillation of Cvetochniy wine material for raw alcohol, the content of aroma-forming substances depended on the content of titrated acids and the varietal characteristics of raw material. Rectification made it possible to reduce significantly the concentrations of undesirable volatile components (isobutanol, isopentanol and others). According to the content of noble aroma-forming substances in the obtained distillation products, it was found that the grapes of Cvetochniy variety are suitable for preparation of strong drinks. The analysis of the data obtained allows us to establish the quality criteria of the finished rectification

A transient study on a solar-assisted combined gas power cycle for sustainable multi-generation in hot and cold climates: Case studies of Dubai and Toronto

Efficiently managing heat losses continues to be a prominent obstacle within gas-fired power plants. The discharge of high-temperature gases from turbines and the considerable pressure generated by compressors present compelling opportunities for augmenting both power generation and overall efficiency. The present study analyzes a gas-fired power plant with two additional Rankine cycles and a concentrated solar power system to enhance efficiency and output power. Clean power generation and distilled water were the outputs of the proposed system. This study also sought to reduce greenhouse gas (GHG) emissions by using solar energy and diminishing the consumption of fossil fuels (CH4) in the combustion chamber. The proposed system was implemented in hot and cold climates. The Brayton cycle of the system was validated through data of a real-life power cycle on the southern coasts of Iran. Furthermore, a transient evaluation was conducted to explore the effects of climatic parameters on the power and desalination system. The contributions of solar irradiance, wind speed, and ambient temperature to the proposed system in a hot climate (Dubai, UAE) and a cold climate (Toronto, Canada) were evaluated. It was found that gas turbine efficiency, compression ratio, and gas turbine input temperature had the greatest effects on the system. Exergy analysis revealed that the combustion chamber, heliostats, the solar receiver, the multi-effect distillation (MED) unit, gas turbine 1, and the thermoelectric generator accounted for the largest portion of the exergy destruction. The case study indicated that the system would work best in climates like Toronto. The findings can be useful to investors and governments in such climates. The proposed system demonstrates its adaptability to regions sharing a climate resembling that of Toronto, making it a viable solution for a wide range of geographical areas. The design and functionality of the system have been meticulously crafted to accommodate the specific environmental conditions present in Toronto and its comparable regions. Gas-fired power plants across numerous countries widely employ the Brayton cycle as their primary operational framework. In this context, the proposed system presents a compelling opportunity to unlock valuable outcomes and advancements.

Maintenance Strategy of a Preheat Train of a Crude Oil Distillation Unit Based on Exergy and Exergoeconomic Analysis

Abstract Established or create new ones to plan the cleaning tasks of the heat exchangers. In this work, a maintenance strategy is developed for a preheating train under the Maintenance Centered on Energy Efficiency (MCEE) methodology, where it is sought to integrate the information of the principles of the second law of thermodynamics with economic variables to use parameters. The modification of the maintenance justification parameter (J) is proposed, adding two new maintenance indicators (W and X). Each one seeks to evaluate an essential criterion for the maintenance area: economic viability, technical feasibility, and benefits, toward the other exchangers in the network after cleaning a specific component. A criticality diagram and a criticality matrix are used. The heat exchangers are grouped into subassemblies, with the leading group consisting of the key heat exchangers (KHEX), the elements of which have a significant impact on the efficiency of the preheat train. For their part, the regions are composed of components whose performance is less considerable than that of the KHEX. In total, 34 maintenance activities will be carried out, distributed among the 25 interchanges of the network. The planning of a program of cleaning activities according to the maintenance strategy based on the methodology of the MCEE establishes a substantial scientific contribution due to the almost null existence of exergetic studies applied to the management of maintenance tasks and focused mainly on the preheating of trains.

Energy Optimization Study In an Ethanol Production Unit Using Pinch Technology

This work presents an energy optimization study in a distillation and dehydration unit of a conventional ethanol producing bio refinery, based on the Pinch method. This proposal resulted in savings of 69.2% in operational costs with utilities, just with energy integration, turning the process significantly cheaper.

Exergy cost accounting thermoeconomic analysis of an oil refinery operating at off-design conditions

ABSTRACT Reducing crude oil quality affects the refinery capacity, quality for downstream units, and overall economics. The thermoeconomic model of a refinery can show that the effects of faults generally propagate through the whole process and affect the behavior of several components, resulting in induced malfunction in typical components. This study aims to estimate the primary source of inefficiency and, therefore, the main reason for the increase in irreversibility and entering feed into the refinery due to changes in some operating conditions. Operating conditions in 2013 and 2023 are defined as base mode and operating mode, respectively. The results of exergy cost analysis show that Liquefied Petroleum Gases (LPG) unit and H2S removal unit have the greatest impact on reducing the overall performance of the refinery in 2023, while this unit is one of the units with the least exergy destruction in the base year. The share of the environment and fuel oil unit, LPG unit, H2S removal unit, and kerosene treating unit in increasing the irreversibility of the utility unit is 4,898.18, 1200.67, 935.15, 642.73, and 624.45 GJ/day, respectively. The share of the Crude Distillation Unit (CDU) in the reduction of the irreversibility of the utility unit is 7,316.67. The results show that the total resource consumption has increased by 168 MJ/day. Therefore, in order to reduce resource consumption in 2030 (operational mode), the impact of LPG and H2S removal units on utility irreversibility should be controlled.

Data-driven models of crude distillation units for production planning and for operations monitoring

This work develops best practices for building consistent data-driven CDU models for production planning and for monitoring. Prior knowledge-based transformations of raw data are shown to be essential to achieve high model accuracy. Data-driven SOM-ResNet and PCA-ResNet deep models, feedforward neural network (FNN), partial least-squares (PLS), and least absolute shrinkage and selection operator (LASSO) are studied. Instead of increasing the dimensionality of data (as in SOM-ResNet), it is better to decrease the dimensionality via PCA and employ deep learning image processing ResNet model. In addition, increasing the number of residual blocks in the PCA-ResNet model increases its accuracy, while adding more hidden layers to FNN does not. With appropriate data selection and transformation, when the number of data samples is less than 500, LASSO model is the best for planning and for monitoring. If the number of data samples exceeds 3,000, then PCA-ResNet model is the best for monitoring.

Experimental and numerical simulation of solar membrane distillation and humidification – dehumidification water desalination system

In this study, a novel solar hybrid air-gap membrane distillation and humidifier-dehumidifier desalination (AGMD-HDD) unit was designed and investigated. In this proposed system, photovoltaic panels were used as the source of electricity in the AGMD-HDD hybrid system. The present work was conducted to explore experimentally the hybrid system's performance within 12 months and simulated numerically using TRNSYS software. The simulated results were in good agreement with the measured values. The flowrate of produced purified water from the solar AGMD-HDD hybrid system were 21.29 kg/h and 11.76 kg/h in the summer and winter seasons respectively. The specific thermal energy consumption (STEC) varied from 60 kWh/m3 to 310 kWh/m3 in summer and 87.12 kWh/m3 - 605.2 kWh/m3 in winter. Freshwater cost estimation using the solar AGMD/HDH system showed a remarkable decrease in freshwater production up to USD 14.32/m3. The gained output ratio (GOR) and the system competence reached 5.33 and 91.03% in summer using a seawater flow rate of 600 kg/h. The total reduction in CO2 emissions was 32 tons in winter and 43 tons in summer seasons.

Boosting kinetic separation of ethylene and ethane on microporous materials via crystal size control

The adsorptive separation of C2H4 and C2H6, as an alternative to distillation units consuming high energy, is a promising yet challenging research. The great similarity in the molecular size of C2H4 and C2H6 brings challenges to the regulation of adsorbents to realize efficient dynamic separation. Herein, we reported the enhancement of the kinetic separation of C2H4/C2H6 by controlling the crystal size of ZnAtzPO4 (Atz = 3-amino-1,2,4-triazole) to amplify the diffusion difference of C2H4 and C2H6. Through adjusting the synthesis temperature, reactant concentration, and ligands/metal ions molar ratio, ZnAtzPO4 crystals with different sizes were obtained. Both single-component kinetic adsorption tests and binary-component dynamic breakthrough experiments confirmed the enhancement of the dynamic separation of C2H4/C2H6 with the increase in the crystal size of ZnAtzPO4. The separation selectivity of C2H4/C2H6 increased from 1.3 to 98.5 with the increase in the crystal size of ZnAtzPO4. This work demonstrated the role of morphology and size control of adsorbent crystals in the improvement of the C2H4/C2H6 kinetic separation performance.

Development of paraffin wax & used cooking oil based composite thermal energy storage for efficient potable water generation in a solar distillation unit

The purpose of this study is to develop a novel composite thermal energy storage system (CTESS) using blends of used cooking oil (UCO) and paraffin wax (PW) and experimentally investigate its effect on the performance of solar still for effective seawater desalination. The CTESS was developed by mixing UCO with PW in various volume ratios and the volume ratio of UCO and PW was optimized at 1:1. The objective was to examine the performance of the solar still with used cooking oil and paraffin wax (SSUCO) and compare it with a conventional solar still (CSS) without any energy storage. The investigation was carried out experimentally, and the results show that the SSUCO significantly enhanced freshwater production compared to CSS. On the first day, the overall freshwater production from SSUCO and CSS was found to be approximately 2870 ml/m2 and 1830 ml/m2, respectively, whereas, on the second day, it was about 2680 ml/m2 and 1750 ml/m2. The productivity of SSUCO increased by 56.83 % and 53.14 % on day 1 and day 2, respectively. The thermal efficiency of SSUCO on day 1 and day 2 was found to be 45.52 % and 41.67 %, respectively, whereas, for CSS, it was 29.03 % and 27.21 %. Economic analysis showed that the cost per litre of yield and payback period for SSUCO was reduced by 40.54 % compared to CSS. Moreover, the environmental analysis revealed that the carbon credit gained by SSUCO was 64.2 % higher than that of CSS. The results indicate that CTESS is a highly promising technique for seawater desalination in solar stills. It provides notable advantages such as increased productivity, enhanced thermal efficiency, and significant economic and environmental benefits.