Column Pressure Research Articles

Measuring intracompartmental pressures for the chronic exertional compartment syndrome: Challenging commercially available devices and their respective accuracy

The aim of this study was to compare commercially available manometers and needles used for intracompartmental pressure measurements for accuracy. An experimental compartment simulation model was developed in order to compare four different terminal devices (Compass manometer, Stryker device, Meritrans transducer, and arterial line) and 22 types of needles. First, all possible device/needle combinations were introduced in rubber ports at the bottom of a water column. The water column was gradually drained three times for each device/needle combination and pressures were recorded by two researchers. This procedure was repeated after placement of a sample of homogenous porcine gluteal muscle tissue. When measuring the fluid column only, all Intraclass Correlation Coefficients were found to be ≥0.980, indicating good resemblance to the reference pressure. After addition of the muscle tissue to the experimental set up, accuracy of the Stryker device and arterial line remained the same. The accuracy of the Compass manometer and Meritrans transducer became less. Excellent reliability was found for 7 out of 22 needles when combined with the Stryker device and for 2 out of 22 needles when combined with the arterial line. The four terminal devices tested were all accurate when measuring pressure in a water column, whereas only the Stryker device and arterial line accurately represented the water column pressure in a porcine gluteal muscle model. Future research will have to verify whether these results can be repeated in human cadaver models and in vivo.

Exergetic Analysis of a Cryogenic Air Separation Unit.

This case study analyzes a cryogenic air separation unit (ASU) with a production of of gaseous oxygen with a concentration greater than 98.5%, operating in Romania on a steel plant platform. The goal of the paper is to provide an extensive model of exergetic analysis that could be used in an optimization procedure when decisional parameters are changed or structural design modifications are implemented. For each key part of the Air Separation Unit, an exergetic product and fuel were defined and, based on their definition, the coefficient of performance of each functional zone was calculated. The information about the magnitude of the exergetic losses offers solutions for their future recovery. The analysis of the exergy destructions suggests when it is worth making a larger investment. The exergetic analysis of the compression area of the ASU points out an exergy destruction and loss of 37% from the total plant’s electrical energy input. The exergy loss with the heat transferred to the cooling system of compressors can be recovered; for the exergy destruction portion, the challenge between investment and operating costs should be considered. The exergy destruction of the air separation columns found the High Pressure Column (HPC) to be more destructive than the Low Pressure Column. The share of the exergy destruction in the total plant’s electrical energy input is 8.3% for the HPC. The local COP of the HPC, calculated depending on the total exergy of the local product and fuel, is 62.66%. The calculus of the air separation column is performed with the ChemSep simulator.

Research of the pulsating flow of drilling fluid in the drill string

The object of research is the pulsating flow of drilling fluid in the drill string. One of the most problematic places is pressure loss due to friction forces distributed along the length of the flow and concentrated in its nodes (threaded joints and pipe bends). In the course of the study, transformation methods were used that allow the drill string to be represented in the form of straight pipes – elements with distributed parameters connected by different inhomogeneities. This makes it possible to reduce the characteristics of the pulsating flow of the drilling fluid to the determination of the lumped parameters of the inclusions, the limiting conditions at the beginning and end of the drill pipes, as homogeneous sections of the drill string. In turn, pressure losses in the drill string during rotary drilling were divided into two types of losses. These are losses along the entire length of the column (flow) and local pressure losses, which are obtained only in certain places of the liquid flow (for example, tool joints, etc.), due to the fact that the flow suffers local deformation. It has been found that from a technological point of view, the most favorable well diameter is the one at which the flow resistance in the pipes is equal to the resistance in the annulus. This is due to the fact that during the flow of the drilling fluid, the speed of the turbulent flow decreases only at the walls of the pipe. Therefore, under the action of centrifugal forces on pipe bends, as in heterogeneities, when local pressure losses occur due to separation of the transit flow, the pipe diameter narrows due to the accumulation of solid particles in whirlpool zones and flow velocities. With a smooth turn of the pipe, the specified separation may be absent. In this case, local pressure losses are largely due to the occurrence of a «steam vortex» at the turn (a helical movement caused by the action of inertial forces). Therefore, a necessary condition for rotary drilling is the continuous circulation of the flushing solution, the complete or partial cessation of which makes further drilling impossible. In this case, the drilling process slows down or leads to an accident. This is due to the accumulation of the hard phase in the places where whirlpools appear. The research results will be useful to scientists and specialists in the oil and gas industry in the physical modeling of well flushing processes in the process of drilling and designing technological flushing processes.

Controls of marine shale gas accumulation in the eastern periphery of the Sichuan Basin, South China

This study examines the mechanisms that most influenced the accumulation of shale gas deposits of the Lower Cambrian Niutitang, Upper Ordovician Wufeng, and Lower Silurian Longmaxi formations of the eastern periphery of the Sichuan Basin. Abundant organic matter (OM) (2.0–5.0 wt%), appropriate thermal maturity (solid bitumen reflectance = 2.5–3.5%), and favorable kerogen types highlight the especially excellent hydrocarbon generation potential of the lower member of the Niutitang Formation and the Wufeng Formation. The development of pores hosted by OM particles and the presence of authigenic quartz account for the elevated porosity (3–5%) of these deposits and their adsorption capacity in the range of 1.5–2.5 m3/t. Strong top and base seals and a pressure coefficient (ratio of reservoir pressure to hydrostatic column pressure) greater than 1.4 of Wufeng Formation shale favor gas preservation in these deposits. However, poor associated sealing lithologies, an excessively high uplift amplitude (> 6900 m), and low pressure coefficient (< 1.0) account for diminished gas preservation in the lower member of Niutitang Formation. The low OM abundance and porosity of the upper member of Niutitang Formation and the Longmaxi Formation are more suggestive of a cap rock than a source or reservoir rock.

Nonlinear Multivariable Control of a Dividing Wall Column Using a Different-Factor Full-Form Model-Free Adaptive Controller

A dividing wall column (DWC), characterized by multivariable control, strong nonlinearity, and highly coupled systems, shows effective distillation capacity with a significant reduction in energy consumption and capital cost. Although multivariable control strategies for DWCs have attracted certain attention from both academia and industry, relatively little work has focused on data-driven multivariable controllers for such a complex system that is not easy to model. In this work, a novel different-factor full-form model-free adaptive controller (DF-FFMFAC) is first proposed for DWCs aiming to solve the problem of simultaneous control of the liquid level, column pressure, and temperature channels with quite different characteristics between them, which may be a challenging task for the prototype FFMFAC. Taking such complex dynamics into account, a parameter selection technique for the DF-FFMFAC based on neural networks is also developed, where gradient descent for the neural network is improved by the full-form dynamic linearization technique utilized in the DF-FFMFAC. Furthermore, the stability of the parameter tuning process is guaranteed by Lyapunov theory. The present work makes a noteworthy contribution to the multivariable control of DWCs in a purely online data-driven way without any offline training procedure and mathematical information. In terms of the separation of an ethanol–n-propanol–n-butanol DWC, the controller is cosimulated in MATLAB/SIMULINK and Aspen Plus Dynamics and tested against a series of feed flow rate and feed composition disturbances. As a result, the proposed method achieves encouraging control performance with smaller oscillations and faster responses compared with model predictive control and proportional–integral–derivative controllers, proving to be a promising data-driven method for the multivariable control of DWCs. Finally, the efficacy of the proposed scheme for the practical control of DWCs in the presence of measurement noise has also been demonstrated by adding white noise to the simulation.

A Coupling Process of Distillation with Vapor Permeation and Adsorption for Production of Fuel Ethanol: A Comparative Analysis on Energy Consumption

To efficiently produce fuel ethanol from fermentation broth, the distillation column was coupled with vapor permeation (VP) of a NaA zeolite membrane instead of using the adsorption technique to remove solvent water. The comparative analysis indicated that the energy efficiency was consistently higher for distillation-VP coupling, using a single-column distillation and three-column distillation, respectively. The best performance was obtained for the VP membrane coupling with a three-column distillation technique, where only 2.7 tons of steam per ton of fuel ethanol were consumed to produce fuel ethanol using a 3.0 wt % ethanol broth. This saved 0.25 tons of steam per ton of fuel ethanol in comparison with the results for the coupling with adsorption technique. The effect of ethanol content in broth on the energy efficiency was also investigated, which indicated that the ethanol content was a decisive factor to determine the energy consumption in the coupling techniques. The operation pressures were crucial to balance the energy consumption between columns coupled with the VP membrane. It was found that the operation pressure of the low-pressure column was the decisive factor to the whole energy efficiency, while the pressure of the high-pressure column was preferably adjusted according to practical production due to fewer disturbances in the system. This work benefits the process design for production of fuel ethanol from fermentation broth.

Факторы и механизмы удлинения твэлов ВВЭР-1000 при термических испытаниях, моделирующих режимы сухого хранения

To prove safety of dry storage conditions, thermal tests of the VVER-1000 fuel rods were performed in electrically heated furnaces in helium gas environment under stationary conditions (they were held at Т = 380 °С for 468 days) and thermal cycling ones (48 temperature cycles in a temperature range of 20 to 380 °С) with duration of cycles varying from 1 to 10 days and the total time of thermal testing of 427 days). The effect of thermal testing on elongation of fuel rods, which were under operation in the VVER-1000 reactors for one year (burnup was ~ 20 (MW⋅days)/kgU) and for six years (burnup was ~ 70 (MW⋅days)/kgU), was studied. It was revealed that high-burnup fuel rods elongated less compared to low burnup fuel rods. The highest elongation values were obtained for the low-burnup fuel rods: it made up 6.0 mm under the stationary operating conditions and 9.5 mm under thermal cycling. Hoop strain of fuel rods increased insignificantly. As there was gas pressure under the cladding, it induced tensile stresses in it at a temperature of 380 °С and thus, stimulated thermal creep. Lower burnup fuel rods could preserve their fuel-cladding gap throughout the entire height of their fuel columns. A model of gas-filled tubular specimen with a textured cladding in which the effective axial stress is enhanced by additional tensile load due to the pressure from fuel column on the spring plunger and a greater recovery of yield strength in the longitudinal direction compared to the transverse one, is applicable to these fuel rods. For high-burnup fuel rods, this model is applicable to for that part of the cladding where it is not in contact with the fuel, i.e. for a shorter length compared to low-burnup fuel rods. Thus, the idea was proved according to which the main mechanism of fuel rod elongation is the thermal creep of the cladding induced by enhanced (due to anisotropic recovery of the yield strength) effective axial stresses resulted from the fuel gas and fuel column pressure on the spring plunger. Thermal cycling leads to greater elongation of fuel rods due to a higher creep rate of the cladding at the unsteady-state stage during short cycles.

Integrated chromatographic approach for the discovery of gingerol antioxidants from Dracocephalum heterophyllum and their potential targets.

As a traditional Tibetan medicine, Dracocephalum heterophyllum has many benefits, but due to the complicated procedures of separation and purification of its chemical constituents, there are few reports on gingerols. In this study, four antioxidative gingerols were isolated from Dracocephalum heterophyllum by an integrated chromatographic approach. Antioxidant activity was then determined by in vitro experiments and its potential targets of action were investigated. First, the extract was pretreated using silica gel, MCI GEL®CHP20P, and diol and spherical medium pressure columns, while the antioxidant peaks were identified using an online HPLC-1,1-diphenyl-2-picrylhydrazyl system. Then, the antioxidant peaks were directionally separated and purified by high pressure liquid chromatography to obtain four gingerols with a purity higher than 95%, namely 5-methoxy-6-gingerol, 6-shogaol, 6-paradol, and diacetoxy-6-gingerdiol. Finally, 1,1-diphenyl-2-picrylhydrazyl assays and cellular antioxidant experiments were carried out, and molecular docking was used to explore potential antioxidant targets. The isolated gingerols upregulated the activity of antioxidant enzymes, including superoxide dismutase (SOD), heme oxygenase-1 (HO-1) and NADPH oxidase 2 (NOX2), while they had little effect on the activity of nadph:quinone oxidoreductase-1 (NQO1). This method can efficiently prepare and isolate antioxidative gingerols from Dracocephalum heterophyllum, and it can be extended to isolate antioxidants from other natural products.

Optimization and simulation of refinery vacuum column with an overhead condenser

Production of clean energy is the major concern for several process industries in recent times such as oil, gas, and petrochemical, however prices are persisted to rise and the optimization of energy in the process industries are keen important. The convectional methods such as distillation column with high energy consumption have been used to convert value added products from crude. Due to frequently uses of the distillation, it is recommended that it should be optimized and utilized efficiently. For the better utilization, it is required to alter the convectional methodology. The new changes can reduce the energy utilization and improve some of consumed energy. In the present paper, investigation on the energy optimization in overhead condenser of a vacuum column of petroleum using cooled water Using Chemcad 5.1 software has been studied. For energy optimization, feed temperature was altered to a suitable temperature (25 °C, 15 °C and 5 °C) for condensation of overhead steam distillation. It is expected that the quality of the hydrocarbon vapors in the overhead condenser outlet would reduce; thereby decreasing the load on the ejector. As per the principle of ejector operation, this would decrease the vacuum column pressure. With reduction in the column pressure, it is expected to introduce the feed at a lower temperature and still operate the column at the same efficiency. It will lower down the burden of energy requirements. This implies reduction in the refinery operating cost. In the next step, the comparison of the three cases, and finally evaluating the overall energy economics were carried out. The main feed was used as a cold fluid in the heat exchanger before the transfer to the main condenser. The result of this study shows that, 1.2532 E+10 cal/hr of energy was required using inleat water temperature of 50 °C in overhead condenser.

ATTEMPT TO IMPROVE THE OPERATING AND TECHNOLOGICAL PROPERTIES OF THE COMBINED GRAIN WASHING MACHINE

Washing machines are used in the production lines of grain cleaning departments of flour mills for thorough cleaning of the grain surface, in particular, its grooves from the remnants of organic and mineral dust, microorganisms and mold. In addition, the grain mass during washing is cleaned of hydrodynamically light and heavy impurities - chaff, seeds of waste plants, straw fragments, mineral particles in the form of sand, small stones, lumps of earth, as well as spores and wormwood seeds. At the same time, foreign odors of grain disappear.Experience in the operation of Ж9-БМА machines shows that along with many advantages, they have some disadvantages. In particular, the productivity of the machine 10 t / h does not correspond to the productivity of the conjugated technological equipment of the production line, and the specific water consumption for washing grain is 1.8… 2.0 l / kg, which is too much in modern conditions of acute shortage of drinking water. Enterprises to abandon the use of washing machines. In addition, certain problems and inconveniences are caused by the design of the sieve shell of the impression column. Stamped sieves with scaly asymmetric holes have a low coefficient of living cross section, which complicates the process of dehydration of washed grain, quickly corrode and rub, require special attention during installation or replacement. Therefore, an attempt is made to eliminate these shortcomings.In particular, the reduction of water consumption is achieved due to the elimination of the grain hydraulic conveyor during its transfer from the washing bath to the pressure column. For this purpose, a device for mechanical overloading of grain by a rotary bucket device located within the alloy chamber is used. At the same time, attention was paid to the separation of light organic impurities from the grain. This decision needs further explanation.The functional diagram shows that the initial grain mixture enters the receiving device, which feeds it with a minimum vertical speed into the ascending water streams created by the screws of two grain augers rotating with the same frequency in the opposite direction. The augers pick up the grain and, keeping it afloat in a suspended state, mix it with the water of the washing bath. At the same time the grain is washed and particles are separated from it, which differ from it in terms of density: mineral impurities begin to sink, fall down and through the longitudinal slit in the auger trough fall into the area of the auger for mineral impurities. This auger transports the "stones" in the opposite direction to the funnel with the ejector of the hydrotransporter of mineral particles. Light impurities, during the transportation of grain by grain augers, float to the surface of the water, the level of which in the washing bath is maintained up to the axis of the augers. Together with grain and water, these impurities are pushed out of the bath into the alloy chamber.In the chamber, in the transverse direction, a pipe with a longitudinal absorption slot is installed, the lower edge of which is immersed in water so that the upper layer of water merges into this slot together with light impurities that have surfaced in the washing bath. The amount of water that fuses light impurities can be adjusted by the depth of immersion in water of the lower edge of the absorption hole. To do this, the pipe is rotated relative to its axis with a special handle with a clamp and a pointing scale. One end of the pipe is closed by a plug, and the other passes through a hole in the wall and drains the water with light impurities into the sink sump. The described device provides almost complete removal of light impurities and minimal consumption of floating water. This solution is in the invention according to the copyright certificate 701708404, developed by specialists of the department TOZV. In addition, certain problems and inconveniences are caused by the design of the sieve shell of the squeezing column. Dirt particles tend to stick to the outer surface of the sieve cylinder and block its holes. This can slow down and even stop the separation of water by centrifugation. Therefore, the upper outer surface of the cylinder is washed with water, which in automatic mode is periodically fed to the sieve by the control device and the solenoid valve. It also saves water.

Effect of concrete type on equivalent lateral confinement pressure in columns under axial loads

The objective of this study is to evaluate the effect of the concrete type, compressive strength of concrete (fc′), amount of transverse reinforcement (Ash), and tie-configuration on the stress–strain curve of confined concrete obtained from the axial performance of lightweight aggregate concrete (LWAC) columns. Sixteen LWAC columns were tested under a concentric axial load. The test results show that the slope of the descending branch in the axial strain against applied axial load decreases with an increase in Ash and decrease in fc′. This trend was more prominent in all-lightweight aggregate concrete (ALWAC) columns compared with sand-lightweight aggregate concrete (SLWAC) columns. For a similar Ash, the strength gain factor (Ks) and equivalent uniform lateral pressure (fle) of ALWAC columns were slightly lower than those of the SLWAC columns, which were considerably lower than those of normal-weight concrete (NWC) columns. In particular, the descending slope of the stress–strain curves of confined concrete was more brittle in ALWAC columns with conventional crossties, lower Ash, and higher fc′ compared to SLWAC with diamond-shaped ties. Consequently, there was a significance discrepancy between measured and predicted values of the stress–strain curves of confined concrete proposed by Saatcioglu and Razvi in the ALWAC column with an Ash value of 1.0, a fcd value of 40 MPa, and conventional crossties, resulting in the highest mean (γm) and standard deviation (γs) of the normalized root-mean-square error (NRMSE).

Facile Fabrication of Zirconium–Organic Framework–Embedded Chitosan Hybrid Spheres for Efficient Fluoride Adsorption

In this research paper, zirconium–organic frameworks [Uio-66, named as Zr@BDC metal–organic frameworks (MOFs)] were prepared using Zr(IV) and 1,4-benzenedicarboxylic acid (BDC) for efficient fluoride removal. However, the prepared Zr@BDC MOFs possess some limitations such as column blockage and pressure drop during field tests. To overcome this difficulty, the prepared Zr@BDC MOFs structurally modified with a chitosan (CS) biopolymer offer easily separable and novel biocomposite spheres, namely, Zr@BDC-CS spheres, for effective retention of fluoride in aqueous media. The structural, surface, crystalline nature, and bonding properties of Zr@BDC-CS spheres were analyzed by refined instrumental techniques, viz., Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS) analyses. The prepared Zr@BDC MOFs and Zr@BDC-CS spheres possess the highest defluoridation capacities (DCs) of 4935 and 4982 mgF– kg–1 within 20 min, respectively. To attain the maximum DC of Zr@BDC-CS spheres, the defluoridation studies were optimized using a batch method. Defluoridation by Zr@BDC-CS spheres was typically dominated by complexation and electrostatic adsorption mechanism. The nature of fluoride adsorption and order of reaction of Zr@BDC-CS spheres were explored by isotherms and kinetic models of adsorption. Moreover, thermodynamic studies show that the fluoride removal of Zr@BDC-CS spheres was spontaneous and an endothermic nature. The suitability in the field level and reusability of Zr@BDC-CS spheres were investigated.

Analysis of Crude Oil Production Using Gas Lift

Gas lift is used to increase production by reduction in the density of the oil column in the tubing, reduction of the flowing bottom-hole pressure which is affected by the hydrostatic pressure of the fluid column and by providing external energy to the oil. In this study an oil field in the Niger Delta was used as case study; it has a production life span of over ten years with characteristics such as high gas-oil ratio (GOR) and high reservoir pressure which makes gas lift suitable for optimizing the wells. The aim of this study is to select the gas lift method suitable for optimum production in the wells using the production modelling softwares PROSPER, and GAP. Simulation studies were conducted using data from two wells in the oil field. The performance of continuous and intermittent gas lifted performance on two wells were compared. The results indicated that continuous gas lift system will be suitable for a well that has high flow rate and high GOR. Also, intermittent gas lift system will be suitable for a well that has lower reservoir pressure and low productivity. Sensitivity analysis of water cuts, gas injection rates and well head pressures were carried out to investigate how the wells will respond to changing operating conditions such as increasing water cut, increasing gas injection rates and increasing well head pressures in the future.

Bubble/micro-bubble regime transition in a pressurized bubble column of a low surface tension liquid system

The objective of this study was to quantitatively analyze bubble/micro-bubble regime transition point in a bubble column. A test was carried out with a cylindrical stainless-steel column having an inner diameter of 0.097 m and a height of 1.8 m. An air was injected as a gas medium. Kerosene with a density of 800 kg/m3, viscosity of 1.64 × 10−3 Pa•s, and surface tension of 23 × 10−3 N/m at 20 ± 2 °C was used as a liquid. The experiment was conducted on a single nozzle plate with different hole sizes (0.7, 1.5, 2.0, and 3.46 mm). To analyze the standard deviation of the differential pressure signal by air bubbles separated from the jet, 12,000 differential pressure data from 0.05 m to 0.15 m of height were measured at 200 Hz under each condition. As gas velocity at the orifice increased, sizes of bubbles falling apart from the nozzle increased. Standard deviation of differential pressure also increased. Bubbles grew until they fell from the tip of the jet. At higher orifice gas velocity, the standard deviation of the differential pressure was reduced due to the occurrence of micro-bubbles. Since the standard deviation of the differential pressure showed a high peak at We/Reg−8 = 1.2 × 1045 for all cases, this value was selected as a demarcation of bubble/heterogeneous micro-bubble regime transition. The standard deviation of pressure drop fluctuation was the lowest at We/Reg−8 = 6.0 × 1048. This point was determined as the homogeneous micro-bubble regime point.

Genetic Algorithm for Pressure-Swing Distillation Optimisation: Ethanol and Ethyl Acetate Mixture

In the acetic acid esterification, ethanol (EtOH) in excess is used to produce ethyl acetate (EtAc), which is commonly used as an organic solvent in biochemical and food industries. On the other hand, EtOH is useful considering the growing production of bioethanol for the fuel market. The resulting mixture of EtAc with unreacted EtOH forms an azeotrope which is difficult to separate by conventional distillation. Literature data shows that the azeotropic binary mixture EtOH – EtAc is separated mostly through extractive distillation. Unfortunately, this procedure has some drawbacks, such as high energy cost and environmental concerns (quite related to the extracting agent recovery). However, taking advantage of the azeotrope sensitivity on pressure, the extracting agent use can be avoided. This paper presents an optimal design for the separation of the above-mentioned mixture, using pressure-swing distillation (PSD) as separation process. In order to achieve a fully optimised system in terms of energy and capital, the method followed consists in simulating the process with Aspen Plus® and making use of genetic algorithms (GAs) to optimise the process variables, including, among others, the pressure of the high-pressure column. This process variable is of great importance, and from our point of view, this factor has not been properly studied nor discussed in literature so far. The starting population consists of points that group a set of values for all the design variables. These sets are a mixture of random and calculated values, obtained by application of heuristics, so that the initial population contains some potentially good initial individuals. The optimisation code is written in Visual Basic language and the link between Aspen Plus® and Visual Basic is also programmed so that a continuous connection can assure information flow from the optimisation program to Aspen Plus® and vice-versa.

Pressure control of fully heat-integrated pressure-swing distillation system using hot-vapor bypass

Fully heat-integrated pressure-swing distillation system is often more economically viable; however, the dynamic behavior of this system is subject to the effect of floating-pressure in the high-pressure column, making the control of this process a challenge. The most common way to control the pressure in distillation columns is by manipulating the coolant flow rate, but this strategy cannot be used in the heat-integrated pressure-swing distillation because of the coupling between reboiler and condenser. Therefore, this study evaluates the use of hot-vapor bypass to control the pressure of the high-pressure column of the pressure-swing distillation process applied to the separation of azeotropic acetonitrile–water system. Disturbances to the fresh feed flow rate and feed composition were performed. The scheme with dual pressure control presented the lowest average value of the IAE. Moreover, all configurations have shown satisfactory results in controlling the products’ composition with an offset of less than 0.013%.

SIMULATION AND OPTIMISATION FOR PRODUCTION OF BIOGAS FROM PALM OIL MILL EFFLUENT (POME) USING ASPEN PLUS

POME undergoes anaerobic digestion to produce biogas, and when it is purified, the biomass can be used as a fuel. This work aims to create a model to simulate the production of biogas and identify the key parameters of the water scrubber using Aspen Plus. The production of biogas was successfully simulated with a relative difference of less than 5%. The key parameters of scrubber in order of percentage contribution to the purity of biogas is as follows, the temperature of water (38.34%), column pressure (35.29%), water flow rate (23.75%) and lastly, number of stages (2.62%). By employing the optimum values, biogas with 99.3% methane purity was obtained.&#x0D; Keywords: Palm oil mill effluent, biogas upgradation, water scrubbing, Aspen Plus, optimisation

Effect of operating pressure on design of extractive distillation process separating DMC-MeOH azeotropic mixture

Although dimethyl carbonate is defined as a green chemical, separation of dimethyl carbonate-methanol azeotropic mixture is an important issue for many dimethyl carbonate production processes. Extractive distillation process is considered as a favorable method for separating this mixture, but the recovery of entrainer still results in a significant loss of capital and operating costs. On the other hand, operating pressure is an important design variable for distillation columns since it has an important impact on column temperature and phase equilibrium. In this work, the effect of operating pressure is investigated for an extractive distillation process separating the dimethyl carbonate-methanol mixture using methyl isobutyl ketone as entrainer. It is observed that the increase in the operating pressure of extractive distillation column significantly decreases the amount of required entrainer flowrate. As the result, a process with an extractive distillation column operating at 10 bar reduces total annual cost and carbon dioxide emissions by 34.1% and 29.8%, respectively compared to the conventional process with an extractive distillation column operating at atmospheric pressure.

Propylene column pressure relief valves chattering resulting in explosion and fire of the Steam Cracker unit

The Refinery and petrochemical production facilities process and produce the gaseous and liquid flammable hydrocarbons under the pressure conditions. In case of any failure, improper design or human mistake there can be autonomous and independent pressure relieve systems activated to release the pressure to the flare systems to protect the equipment against the overpressure, damages and other consequences. The paper describes the failure occurred at the Steam Cracker unit in Litvinov, Czech Republic in 2015. As a result of a loss of cooling followed by loss of reflux event, the pressure relief system of the Propylene Column was activated whereas the pressure relief valves opened up and chattered, resulting in loosening of flange bolts and loss of containment. The release of the propylene vapor ignited, resulting in subsequent explosion and fire at the Propylene Column area. The interruption of steam and instrument air supply caused by the fire damages led to the other extensive fire of four pyrolysis heaters. The extraordinary event description, root cause analysis, investigation as well as the corrective actions are introduced and analyzed.

Air column of pressure hydrocyclone with pneumatic regulator

A reliable non-contact pneumatic pressure regulator of a pressure hydrocyclone is offered. The regulator is installed in the area of ​​the sand nozzle. The pneumatic regulator of the standard pressure cylindrical-conical hydrocyclone provides non-contact thickening of the product in the area of ​​the sand nozzle. In the process of controlling the operation of the hydrocyclone along its axis, an air column is formed. Features of the regulator affect the formation of the air column of the hydrocyclone. The pressure in the air column is manometric.&#x0D; The task is to investigate the effect of pulp pressure at the inlet of the hydrocyclone, pulp thickening and air column pressure. Experimental studies were performed in the laboratory on a model of a standard industrial cylindrical-conical hydrocyclone HC360. The connection between the technological parameters of the hydrocyclone operation and the pressure in the air column has been studied. to establish possibilities of control of work of a hydrocyclone on pressure in an air column. The planning of the experiment in the laboratory on a hydrocyclone model was performed in the program Statgraphics Centurion XV.&#x0D; Experimental studies were performed for the optimal parameters of the angle and slit of the pneumatic regulator. The optimization criterion is chosen – the maximum effect of pulp thickening while minimizing local energy losses in the nozzle. In laboratory conditions, the change in pulp pressure and density at the inlet of the hydrocyclone over the entire operating range is simulated. The laboratory model of the hydrocyclone was made on a scale of M1:10. Flotation waste was used as pulp. Modeling of hydrocyclone operation as a part of water-sludge system at the concentrator is carried out. The density of the solid phase is 1500 kg/m3.&#x0D; The solids content at the inlet is 10 g/l. Samples were taken by volumetric measurement with a measuring vessel. A statistically significant relationship between the pressure in the air column of the hydrocyclone and the effect of pulp thickening in a standard cylindrical-conical hydrocyclone was established. The presence of the linear character of the dependence of the coefficient of thickening and pressure in the air column of the hydrocyclone with the pneumatic regulator is checked. The absence of a statistically significant effect of hydrocyclone supply pressure on the dependence of other selected factors was established.&#x0D; Experimental studies were carried out at the optimal design parameters of the pneumatic regulator according to the criteria of minimizing the loss of energy of air current in the nozzle and minimizing the volumetric flow of air.