Vapor-liquid Ratio Research Articles

Phase Behavior of Hydrocarbon Fluids in Shale Reservoirs, Considering Pore Geometries, Adsorption, and Water Film.

Phase behavior of hydrocarbon fluids in nanopores is different from that observed in a PVT cell due to the confinement effect. While scholars have established various models for studying the phase behavior in nanopores, the authors often ignore the effect of pore geometries, which can significantly affect the critical fluid properties in shale nanopores. In this study, we extend the Soave-Redlich-Kwong equation of state (SRK EOS) using potential theory and establish models of critical property shift, considering pore geometries, adsorption, and water film. Our research shows that the critical property shifts, considering fluid adsorption, begin at rp ≤ 10 nm and are seriously strengthened with nanopore radius reduction. The extended SRK EOS is applied to compute phase diagrams of the 50% C1-50% nC10 mixture at different pore sizes and find that the thickness of adsorption and water film causes a depression in the P-T diagram and that the bubble point pressure is lower in cylindrical pores. At pressures above 6 MPa, the irreducible water saturation and pore geometries greatly impact the vapor-liquid ratio. This study is significant for evaluating residual oil distribution and studying fluid flow laws in shale reservoirs.

SHELL-AND-TUBE HEAT EXCHANGER WITH VARIABLE VAPORLIQUID RATIO FOR NATURAL GAS PROCESSING PLANTS WITH DEEP EXTRACTION OF C2+ HYDROCARBONS

Due to the limited quantitiesand high cost of energy resources, the task of reducing their consumption at existing gas processing plants is crucial. One of the methods to save energy is to optimize the distribution of heat flows at a process unit. The most energy-consuming unit in natural gas processing plants isademethanizer, so the decision to optimize the operation of this unit is practical.To this end, the article discusses the existing options of layout for the stripping section of the unstabilized gas condensatedemethanizer at natural gas processing plants with deep extraction of C2+hydrocarbons.The peculiarities of equipment layout for the stripping section of the demethanizer in all the considered options have been studied in detail. The positive and negative sides of each option have been revealed.A proprietary design is proposed for a shell-and-tube heat exchanger with a phase interface that performs the function of a stripping section for the demethanizer. A comparative analysis of using a horizontal thermosyphon evaporator and a shell-and-tube heat exchanger with a variable vapor-liquid ratio under the same operating conditions is given. As a result, it was revealed that the total weight of equipment and overall dimensions of the steel structure in the first option are greater than in the second one. It is established that the latter solution will simplify the layout of the demethanizer unit and improve the process performance of the plant, providing an advantage over the existing technology solutions. Besides, the design of this equipment makes it possible to use it in gas processing plants with low-temperature processing of natural gas.

Impact of Adding Bioethanol and Dimethyl Carbonate on Gasoline Properties

Bioethanol and dimetyl carbonate (DMC) are considered alternative fuels and additives to the synthesis compounds used now, since bioethanol is a biofuel and dimethyl carbonate (DMC) is non-toxic, biodegradable and can be produced in a cleaner way. In this study, the effect of adding dimethyl carbonate (DMC) and ethanol to gasoline on the volatility was investigated. The volatility was the main goal of this research but also, the effect on the antiknock properties was studied. Mixtures of gasoline with DMC or with bioethanol were prepared in different proportions of additive: 3%, 6% and 9% v/v. Additionally, mixtures with 3% v/v ethanol plus 3% or 6% v/v DMC, and3% DMC plus 6% v/v ethanol were prepared. For the volatility evaluation, the ASTM distillation curve and vapor pressure of these mixtures were determined experimentally in order to predict the performance of the resulting fuels. When adding oxygenated compounds, the increase in vapor pressure was proportional to the additive quantity. Additionally, modifications of the ASTM distillation curves were observed, with these indicating the formation of minimum boiling point azeotropes and the corresponding increase in volatility, with good effect on the ease of ignition in the engine. Based on the experimental results, the vapor lock index VLI, drivability index DI and vapor–liquid ratio temperature T(V/L=20) were calculated to quantify the volatility. The experimental results showed that gasoline mixtures with these oxygenated compounds show a significant increase in antiknock properties. Thus, for mixtures with ethanol, the research octane number (RON) increases by up to 2.2 units and the motor octane number (MON) increases by up to 1.2 units. Gasoline mixtures with DMC have another behavior: RON increased by up to 1.5 units, while the MON value increased by up to 2.5 units. For an initial gasoline with RON = 94.7 and MON 84.7, these increases are important and make the difference by exceeding the RON = 95 limit. Adding dimethyl carbonate to gasoline–ethanol blends improves the sensitivity of the fuel.

Finding a way through the “misty” evaluation of the flammability and explosivity of kerosene aerosols

• JetA1 mist flammability and explosivity are assessed in a confined explosion vessel. • Influence of initial conditions on explosion sensitivity and severity is studied. • JetA1 mists with a small droplet size have a higher rate of pressure rise. • The MIE of JetA1 mist may be lower than that of vapors at low temperatures. • The vapor/liquid ratio of a mist is a key parameter of its explosion severity. In the context of assessing hydrocarbon mist ignition sensitivity and explosion severity, an original test method is proposed, focusing on kerosene JetA1 mists but is applicable to other hydrocarbons. Experiments were carried out in a modified apparatus based on the 20L explosion sphere. Fine control of the gas/liquid ratio and flow rates, the mist concentration, and the ignition energy and duration, was ensured by a specifically customized control system guaranteeing the flexibility and compliance of the test apparatus. The droplet size distribution (DSD) and the level of turbulence of the JetA1 mist cloud were first determined by an in-situ laser diffraction sensor and by Particle Image Velocimetry, respectively. The lower explosive limit (LEL), the minimum ignition energy (MIE), the limiting oxygen concentration (LOC), the maximum explosion overpressure (P max ), and the maximum rate of pressure rise (dP/dt max ) were then determined for different mist concentrations, ambient temperatures, initial turbulence levels, energies, and DSD. Tests showed that the LEL mist of JetA1 mists of an average diameter of 8 µm is around 94 g/m 3 , a value which increases to 220 g/m 3 with increasing DSD. This value also tends to decrease considerably with increasing temperatures. Moreover, at a JetA1 concentration of 125 g/m 3 , P max and dP/dt max as high as 6 bar and 192 bar/s respectively were reached, the latter increasing to about 480 bar/s at T = 60 °C. These mists were shown to be ignitable using energies as low as 200 mJ, which is lower than that of vapors at low temperatures, and a limiting concentration of oxygen of 15.8 % v/v . The potential presence of hydrocarbon mist should therefore be an element that requires reconsidering the classification of hazardous areas. Finally, to stress the influence of the vapor-liquid ratio present in the cloud before ignition on the combustion kinetics, an evaporation model based on the d 2 -law was developed estimating the evaporation time and the vapor quantity at different initial temperatures or droplet diameters. Findings were shown to be well coherent allowing the proposition of a new technique for determining hydrocarbon mist safety criteria. Finally, results have shown that JetA1 mists can ignite at temperatures below the liquid’s flashpoint under varying turbulence levels and droplet size distributions.

A step toward lifting the fog off mist explosions: Comparative study of three fuels

Gases, vapors, and dusts are all potential explosion threats; however, mists should also be taken into account. Indeed, dozens of accidents involving hydrocarbon mists were identified in incident surveys. Mist explosions continue to occur, highlighting the need to evaluate and assess the validity of present approaches for assessing mist ATEX risks and to establish reliable standardized safety parameters for fuel mists.In a modified apparatus based on the 20 L explosion sphere, three fluids of industrial interest were investigated. A new siphon injection system comprising a Venturi junction was installed, offering a wide range of dispersion performances. This system was controlled by a specifically developed program, ensuring the apparatus's versatility and adaptability to various tested liquids. It enables precise control of the gas carrier flow, liquid flow, and injection and ignition durations, allowing modification of the dilution rate of a particular droplet size distribution (DSD). The mist cloud dispersed in the 20 L sphere was characterized by determining its DSD using an in-situ laser diffraction sensor and by performing Particle Image Velocimetry (PIV). Mists of kerosene, diesel and ethanol were then subjected to tests to assess their lower explosive limit (LELmist), minimum ignition energy (MIE), maximum explosion pressure (Pmax), and rate of pressure rise (dP/dtmax). For instance, it was found that the LELmist of ethanol, kerosene Jet A1, and diesel fuel for a DSD averaged at 8–10 μm reach 77, 94, and 93 g/m3 respectively. This LELmist was also shown to increase with increasing DSD in the case of Jet A1 mists. A sensitivity study was also performed to emphasize the impact of parameters such as the fuel type, the DSD, and the mist temperature. Findings showed that the explosion severity is strongly influenced by the chemical nature and the volatility of the dispersed fuel. Moreover, controlling the sphere temperature was proven to be a crucial step when using such apparatus for the evaluation of the explosibility of mists. An evaporation model based on the d2 law was also developed to visualize the vapor-liquid ratio before ignition. These findings have already led to the development of a new procedure for determining safety standards for hydrocarbon mists, as well as tools to assess mist explosion risks. They have proven that it is possible to evaluate the ignition sensitivity and explosion severity of fuel mists using a single well-known apparatus.

Mineralogy and fluid characteristics of the Waschleithe Zn skarn – a distal part of the Schwarzenberg mineral system, Erzgebirge, Germany

The Waschleithe skarn is situated in the northern sector of the Schwarzenberg district in the western Erzgebirge (Germany), a district which hosts several large polymetallic skarn deposits. The Waschleithe is a Zn-dominant skarn comprising abundant dark Mn-rich hedenbergite, minor grandite garnet and magnetite related to the prograde stage as well as epidote, quartz, fluorite, amphibole, chlorite, ilvaite and Mn-rich pyroxenoids related to the retrograde stage of skarn formation. Ore minerals are related to the early retrograde stage and include sphalerite, galena, chalcopyrite, pyrite as well as minor amounts of scheelite and cassiterite. Fluid inclusion homogenization temperatures range from ~385 to 360 °C and from ~320 to 285 °C for the prograde and retrograde skarn stage, respectively. Thus, late-stage cooling is proposed as the major controlling factor for sulfide mineral precipitation. Fluid salinities for both stages are very low (<3% eq. w[NaCl]) and all observed fluid inclusion assemblages show homogeneous liquid–vapor ratios. Formation pressures >25 MPa suggest a minimum depth of formation of approximately 3 km. Oxygen fugacity during prograde skarn formation was initially low and increased towards the late prograde stage. The late-Variscan Eibenstock granite is identified as the most likely source of the skarn-forming fluids. The recognition of the Waschleithe skarn as a distal Zn skarn has major implications for the understanding of the Schwarzenberg district mineral system and provides valuable information for exploration targeting.

Simulation and assessment of manufacturing ethylene carbonate from ethylene oxide in multiple process routes

• Two processes of manufacturing EC from EO without EO purification are developed. • The rigorous models are established for the developed two processes. • Various schemes for absorbing EO are designed to reduce the liquid–vapor ratio. • Material chain analysis is performed to explore connections of each section of the processes. Ethylene oxide (EO) is an important raw material for producing ethylene carbonate (EC). However, the traditional method for the separation of EO from mixture gas by water in the refining process is high energy consumption. In this paper, two processes of manufacturing EC from EO mixture gas were studied by process simulation. Two processes for producing EC from EO mixture as raw materials without EO purification, called the OSAC process and the Modified OSAC process, were developed and assessed systematically. Both processes use EC as the absorbent to capture EO, avoiding the separation process of EO from solution. For comparisons, the EC producing process containing EO absorption by water, EO refinement and carbonylation process were also modeled, which was called the ERC process. Three schemes were designed for the EO absorber using EC as absorbent. Compared with the initial absorber scheme, the optimal liquid–vapor ratio is reduced from 1.66 to 1.45 (mass). Moreover, the mass distribution analysis for the three processes were carried out in the form of the material chain. It was found that, compared with the ERC process, the energy consumption of the OSAC and the Modified OSAC process is reduced by 56.89% and 30.03%, respectively. This work will provide helpful information for the industrialization of the OSAC process.

Heat-transfer distribution optimization for the heat-integrated air separation column

The heat-integrated air separation column (HIASC) is an advanced energy-saving technology for the cryogenic air separation process, although a large capital investment is required for installed heat exchangers. These heat exchangers have a location-dependent effect upon the separation which leaves room for optimization. This paper, therefore, aims to optimize the heat-transfer distribution of HIASC regarding minimum heat exchanger costs while maintaining the low energy consumption level. Results indicate that the heat-transfer tends to concentrate at both ends of the column. The influence of operational parameters is further studied by the idea based on the liquid-vapor ratio. Finally, an optimal HIASC with respect to the minimal heat exchanger investment is obtained, and the heat exchanger costs are reduced by 44.4% compared with the uniform distribution with a similar energy-saving level.

A New Cavitation Algorithm to Support the Interpretation of LIF Measurements of Piston Rings

&lt;div class="section abstract"&gt;&lt;div class="htmlview paragraph"&gt;Laser induced fluorescence (LIF) is used to investigate oil transport mechanisms under real engine conditions. The engine oil is mixed with a dye that can be induced by a laser. The emitted light intensity from the dye correlates with the residual oil at the sensor position and the resulting oil film thicknesses can be precisely determined for each crank angle. However, the general expectation is not always achieved, e.g. an exact representation of piston ring barrel shapes. In order to investigate the responsible lubrication effects of this behavior, a new cavitation algorithm for the Reynolds equation has been developed. The solution retains the mass conservation and does not use any switch function in its mathematical approach. In contrast to common approaches, no vapor-liquid ratio is used, but one or several bigger bubbles are approximated, as have been observed in other experiments already. As a result, not only the known boundary conditions for the Reynolds equation become unnecessary, but the solution also gives a clearer idea as to the shape of the cavitation bubble. The combination of simulated oil film thicknesses, the resulting cavitation bubbles and the fixed field of view from the LIF sensor allows a reproduction of the measurement signal. The comparison of measurement and simulation exhibits a high correlation, and thus enables a deeper knowledge and understanding of the real conditions inside a combustion engine. On the other hand, it can be seen that effects such as a decrease in the LIF signal in the cavitation area is much lower than would be expected according to the literature.&lt;/div&gt;&lt;/div&gt;

Reformate-enriched gasoline-ethanol blends: Volatility criteria and azeotrope formation

Four hydrocarbon-base gasolines (BG) were formulated from the local refinery streams; isomerate, reformate, and light naphtha. The formulations were enriched in reformate. Each of these BG formulations was blended with 10 vol% of anhydrous ethanol. From ASTM-D86 distillation data, eight distillation curves were constructed and the trend line equations of these distillation curves were developed. Also, the area under each distillation curve (AUDC) was calculated through calculus definite integration technique. Subsequently, the area due to azeotrope formation (ADAF) for each BG-ethanol blend was estimated. In this paper, the influence of increasing reformate proportions on the created positive azeotrope, was studied. Also the influence of increasing reformate proportions on vapor pressure, Temperature for the vapor-liquid ratio of 20, T50 and octane number was studied. The results show that the R2 values of the distillation curve equations prove the reliability of the fits. Also, increasing reformate proportion in the fuel blend improves the octane number while increasing reformate proportion decreases the volatility of the fuel formulation.

Geology, Alteration, and Mineralization of the Kay Tanda Epithermal Gold Deposit, Lobo, Batangas, Philippines

AbstractThe Kay Tanda epithermal Au deposit in Lobo, Batangas is one of the Au deposits situated in the Batangas Mineral District in southern Luzon, Philippines. This study aims to document the geological, alteration, and mineralization characteristics and to determine the age of the mineralization, the mechanism of ore deposition, and the hydrothermal fluid characteristics of the Kay Tanda deposit. The geology of Kay Tanda consists of (i) the Talahib Volcanic Sequence, a Middle Miocene dacitic to andesitic volcaniclastic sequence that served as the host rock of the mineralization; (ii) the Balibago Diorite Complex, a cogenetic intrusive complex intruding the Talahib Volcanic Sequence; (iii) the Calatagan Formation, a Late Miocene to Early Pliocene volcanosedimentary formation unconformably overlying the Talahib Volcanic Sequence; (iv) the Dacite Porphyry Intrusives, which intruded the older lithological units; and (v) the Balibago Andesite, a Pliocene postmineralization volcaniclastic unit. K‐Ar dating on illite collected from the alteration haloes around quartz veins demonstrated that the age of mineralization is around 5.9 ± 0.2 to 5.5 ± 0.2 Ma (Late Miocene). Two main styles of mineralization are identified in Kay Tanda. The first style is an early‐stage extensive epithermal mineralization characterized by stratabound Au‐Ag‐bearing quartz stockworks hosted at the shallower levels of the Talahib Volcanic Sequence. The second style is a late‐stage base metal (Zn, Pb, and Cu) epithermal mineralization with local bonanza‐grade Au mineralization hosted in veins and hydrothermal breccias that are intersected at deeper levels of the Talahib Volcanic Sequence and at the shallower levels of the Balibago Intrusive Complex. Paragenetic studies on the mineralization in Kay Tanda defined six stages of mineralization; the first two belong to the first mineralization style, while the last four belong to the second mineralization style. Stage 1 is composed of quartz ± pyrophyllite ± dickite/kaolinite ± diaspore alteration, which is cut by quartz veins. Stage 2 is composed of Au‐Ag‐bearing quartz stockworks associated with pervasive illite ± quartz ± smectite ± kaolinite alteration. Stage 3 is composed of carbonate veins with minor base metal sulfides. Stage 4 is composed of quartz ± adularia ± calcite veins and hydrothermal breccias, hosting the main base metal and bonanza‐grade Au mineralization, and is associated with chlorite‐illite‐quartz alteration. Stage 5 is composed of epidote‐carbonate veins associated with epidote‐calcite‐chlorite alteration. Stage 6 is composed of anhydrite‐gypsum veins with minor base metal mineralization. The alteration assemblage of the deposit evolved from an acidic mineral assemblage caused by the condensation of magmatic volatiles from the Balibago Intrusive Complex into the groundwater to a slightly acidic mineral assemblage caused by the interaction of the host rocks and the circulating hydrothermal waters being heated up by the Dacite Porphyry Intrusives to a near‐neutral pH toward the later parts of the mineralization. Fluid inclusion microthermometry indicates that the temperature of the system started to increase during Stage 1 (T = 220–250°C) and remained at high temperatures (T = 250–290°C) toward Stage 6 due to the continuous intrusion of Dacite Porphyry Intrusives at depth. Salinity slightly decreased toward the later stages due to the contribution of more meteoric waters into the hydrothermal system. Boiling is considered the main mechanism of ore deposition based on the occurrence of rhombic adularia, the heterogeneous trapping of fluid inclusions of variable liquid–vapor ratios, the distribution of homogenization temperatures, and the gas ratios obtained from the quantitative fluid inclusion gas analysis of quartz. Ore mineral assemblage and sulfur fugacity determined from the FeS content of sphalerite at temperatures estimated by fluid inclusion microthermometry indicate that the base metal mineralization at Kay Tanda evolved from a high sulfidation to an intermediate sulfidation condition.

Geology, geochemistry, and geochronology of the East Bay gold trend, Red Lake, Ontario, Canada

The Red Lake greenstone belt is situated in northwestern Ontario within the Uchi Subprovince, Superior Province. Most gold deposits therein are associated with major deformation corridors; the east-west oriented “Mine trend” hosts most of the large deposits and the northeast-southwest “East Bay trend” hosts several small deposits and showings. Gold along the East Bay trend typically occurs in quartz replacement veins that were emplaced into pre-existing quartz-carbonate veins. Gold can occur as free gold or along vein margins associated with pyrite and pyrrhotite. Most primary fluid inclusions, preserved in relatively undeformed portions of veins, are carbonaceous with lesser quantities of aqueous inclusions. The average homogenization temperature of aqueous fluids is ~250 °C; however, the abundance of three-phase inclusions, variation in liquid-vapor ratios, and a wide range in homogenization temperatures indicate that immiscibility, effervescence, and fluid mixing are mechanisms associated with gold deposition. The age (~2550 Ma) of alteration minerals in the Abino area is considerably younger (by ~100 Myr) than alteration minerals in other deposits in the Red Lake district, indicating that the mineralizing fluid history was more protracted than previously thought. Along the East Bay trend, barren veins generally have lower δ18OVSMOW values (0.0 to 8.5‰) relative to auriferous veins (9.6 and 13.1‰). Consequently, the oxygen isotopic composition of quartz could be used as a vector for gold mineralization. The genetic model for the East Bay trend involves several stages of vein formation. Auriferous veins formed near the upper boundary of the mesozonal regime (depth of ~5–6 km).

Why Crude Oil Vapor Pressure Should Be Tested Prior to Rail Transport

Recent crude oil rail car accidents have forced US and Canadian authorities to issue Emergency Testing Orders to ensure safe transportation of crude oils. One crucial parameter in meeting these safety requirements is the testing of the vapor pressure (VP) of crude oil. This paper explains the impact of highly volatile components inside the crude oil on the vapor pressure measurement. It describes typical VP measurement errors and discusses guidelines and technology for proper crude oil classification. It offers measurement data to show the effect of sample outgassing and to describe the impact of temperature changes and the vapor-liquid ratio (V/L) on vapor pressure test results. The second part of the paper discusses methods to measure the True Vapor Pressure (TVP) and Bubble Point Pressure (BPP) of Crude Oils for safety purposes. Key words : Crude oil; Volatility testing; Safety data sheet; Hazardous material regulations (HMR); Emergency testing order; Vapor pressure (VP); ASTM D6377; Reid vapor pressure (RVP); ASTM D323; True vapor pressure (TVP); Vapor-liquid ratio (V/L); Bubble point pressure (BPP); Floating piston cylinder (FPC)

Design method for multi-component distillation system based on quasi-binary method

A novel design method for a multi-component distillation system based on the quasi-binary model is presented. The quasi-binary method, which converts the multi-component system to a quasi-binary system, could simplify the design process of multi-component distillation. Subsequently the software integration method is introduced to the distillation design and an automatic calculation program is developed by using Visual C++ language. The design of multi-component distillation, in which the minimum reflux ratio Rmin or liquid-vapor ratio (L/V)min and the minimum numbers of stage Nmin is determined easily and quickly, is automatically performed by the technology of software integration. Three examples are solved to demonstrate the feasibility and effectiveness of the presented method for the multi-component distillation.

Femtosecond lasers in fluid inclusion analysis: Three-dimensional imaging and determination of inclusion volume in quartz using second harmonic generation microscopy

Optical second harmonic generation microscopy was used to generate three-dimensional images of fluid inclusions in quartz. Because the exciting light was focused with a high numerical aperture microscope objective, phase-matching conditions in the quartz led to the generation of frequency doubled light only at the surfaces of the fluid inclusions and not in the bulk material, providing an axial resolution of approximately 1 μm. The volume of synthetic two-phase water inclusions was determined from second harmonic images. The bubble volume was measured using brightfield microscopy (the sample was heated to ensure a smaller bubble that could take on a spherical shape inside the inclusion). The bulk molar volume was then calculated from the vapor–liquid ratio. The values obtained for the bulk molar volume were found to be in good agreement with values calculated from measurements of the homogenization temperature.

Phase Equilibria of Ethanol Fuel Blends

AbstractFor Abstract see ChemInform Abstract in Full Text.

Phase equilibria of ethanol fuel blends

The blending of ethanol into fuels is expected to increase significantly in the coming years. In some regions of the United States, ethanol has already replaced MTBE as the oxygenate blended into gasoline. Biofuel blends, such as blends of gasoline with ethanol made from biomass, can play an important role in helping governments and corporations meet sustainability targets. However, the introduction of ethanol fuel blends into the market place requires addressing several issues related to phase equilibria. The highly non-ideal mixing of ethanol with hydrocarbons has a dramatic impact on phase behavior, with consequences for the production, storage, distribution, and use of ethanol-blended fuels. In this paper, we will (a) illustrate the impact of ethanol use on the transportation fuels industry, (b) use thermodynamics as a unifying theme to understand these phenomena, and (c) review available data and the state-of-the-art in modeling these effects. Topics will include (a) volatility characteristics (e.g. Reid vapor pressure, ASTM D-86 Distillation, vapor–liquid ratio, and evaporative emissions), (b) phase separation effects (e.g. water tolerance and enhanced solubility of aromatic fuel components in groundwater), (c) commingling of ethanol and non-ethanol fuels, and (d) materials compatibility (e.g. increased swelling and permeation).

Finite-difference lattice Boltzmann model with flux limiters for liquid-vapor systems

In this paper we apply a finite difference lattice Boltzmann model to study the phase separation in a two-dimensional liquid-vapor system. Spurious numerical effects in macroscopic equations are discussed and an appropriate numerical scheme involving flux limiter techniques is proposed to minimize them and guarantee a better numerical stability at very low viscosity. The phase separation kinetics is investigated and we find evidence of two different growth regimes depending on the value of the fluid viscosity as well as on the liquid-vapor ratio.

Heat and mass transfer model approach to optimum design of cryogenic air separation plant by packed columns with structured packing

Abstract A process simulator for design of a cryogenic air separation plant by packed columns with structured packing was developed by use of our heat and mass transfer model. The heat and mass transfer rates were estimated by correlations which were proposed in our previous work (J. Chem. Eng. Japan 33 (2000) 245). Comparison of the predicted separation performance of a pilot-scale cryogenic air separation plant by the developed simulator with the observed data was made. Predicted concentration profiles in the low pressure column and the ones in the argon column showed good agreement with observed data. The effects of the side-cut location to the argon column, the liquid-feed location to the low pressure column, and the vapor–liquid ratio in the feeds to the low pressure column for a commercial-scale cryogenic air separation plant, which consisted of a high pressure column with 50 sieve trays, a 3.2-m diameter low pressure packed column with structured packing, and a 2.5-m diameter argon column with structured packing, on purity of the product nitrogen, oxygen and crude argon were also discussed.

Heat and Mass Transfer Model Approach to Prediction of Separation Performance of Cryogenic Air Separation Plant by Packed Columns with Structured Packing.

A process simulator for prediction of separation performance of a cryogenic air separation plant by packed columns with structured packing is developed by use of our heat and mass transfer model. The basic equations for the simulation are mass transfer correlations which were proposed in our previous work (Egoshi et al., 2000). Comparison of observed data from a pilot-scale cryogenic air separation plant, which consisted of a 710 mm-diameter high pressure sieve plate column for feed to low pressure column, a 500 mm-diameter low pressure packed column with structured packing for production of pure grade nitrogen and oxygen, and a 380 mm-diameter argon column with structured packing for production of crude argon is made. Predicted concentration profiles in the low pressure column and the ones in the argon column show good agreement with observed data. The effect of liquid feed location, side-cut location, vapor-liquid ratio of the feeds to the low pressure column on purity of the product nitrogen, oxygen and crude argon are also discussed.