Compressor Oil Research Articles

Risk Screening as Input for Risk Assessment of Rotating Equipment

Risk assessment of complex rotating equipment is costly and time consuming process. Due to the reason, only critical equipment should be considered for detailed risk assessment. In this study, a semi-quantitative risk assessment model was developed to assess the risk of rotating equipment. The model consists of four main parts, initial risk screening, risk assessment, Failure Mode and Effect Analysis (FMEA) and maintenance strategy planning based on reliability concept. The model was used to assess risk of rotating equipment of power generation unit. Initial risk screening indicated compressor, combustion chamber, turbine and lube oil system of the power generation system as critical equipment under serious risks. Risk assessment using Borda ranking minimized the risk ties and showed compressor, combustion chamber and turbine were more critical as compared to lube oil system. Failure modes were identified using FMEA, 68% of the downtime was due to compressor, combustion chamber and turbine failure modes. Only 32% of the downtime was due to lube oil subsystems failure modes. Maintenance interval for compressor, combustion chamber and turbine was calculated 2 months and 5 months for lube oil system to reduce risk.

Quantitative estimation of overpressure caused by gas generation and application to the Baiyun Depression in the Pearl River Mouth Basin, South China Sea

AbstractHydrocarbon generation can yield high fluid pressures in sedimentary basins as the conversion of solid kerogen to hydrocarbons can result in an increase in fluid volume. To quantify the relationship between gas generation and overpressure in source rocks, a set of equations for computing the pressure change due to gas generation has been derived. Those equations can be used to quantitatively estimate overpressure generated by type III kerogen in source rocks by considering gas generation and leakage, gas dissolution in formation water and residual oil, thermal cracking of oil to gas, and hydrocarbon episodic expulsion from source rocks. The equations also take consideration of other factors including source rock porosity, transformation ratio, total organic carbon (TOC), hydrogen index, and compressibility of kerogen, oil, and water. As both oil and gas are taken into account in the equations, they can also be used to estimate the evolution of overpressure caused by hydrocarbon generation of type I and type II kerogen source rocks. Sensitivity analyses on the type III kerogen source rock indicate that hydrogen index is the most influential parameter for overpressure generation, while TOC and residual gas coefficient (β: ratio of residual gas over the total gas generated) have a moderate effect. Overpressure can be generated even if the gas leakage/loss in the source rock is up to 80% of the total gas generated. This suggests that the internal pressure seal of the source rock is not a critical factor on the pressure change as long as the source rocks are capable of sealing liquid oil. The equations were applied to evaluate the overpressure in the Eocene–Oligocene Enping Formation source rocks due to hydrocarbon generation in the Baiyun Depression, the Pearl River Mouth Basin by considering the source rock properties, hydrocarbon generation history, and hydrocarbon expulsion timing. Two episodes of overpressure development due to gas generation and release were modeled to have occurred in the Enping Formation source rock since 16 Ma. The overpressure release at 10.2–5.3 Ma via hydrocarbon expulsion was apparently related to the Dongsha phase of tectonic deformation, whereas the pressure release at 2–0 Ma was due to pressure generation that was exceeded the fracture‐sealing pressure in the source rocks.

Application of SiO2 Nanoparticles as Lubricant Additive in VCRS: An Experimental Investigation

In this work, the SiO2 nano-oil is proposed as a promising lubricant to enhance the performance of vapour compression refrigerator compressor. The stability of SiO2 nanoparticles in the oil is investigated experimentally. It was confirmed that the nanoparticles steadily suspended in the mineral oil at a stationary condition for long period of time. The application of the nano-oil with specific concentrations of 1%, 2% and 2.5 %( by mass fraction) were added in the compressor oil. The VCRS performance with the nanoparticles was then investigated using energy consumption tests. The result shows the COP of system were improved by 7.61%,14.05% & 11.90%, respectively, when the nano-oil was used instead of pure oil.

Measurement of oil entrainment rates and drop size spectra from coalescence filter media

Liquid entrainment from coalescence filter media—i.e. flow induced “blow-off” of previously deposited oil—in the form of droplets is poorly understood, for one because the generated spectrum is very wide and difficult to characterize with temporal and size resolution, especially for very large drops which carry most of the mass. Such filters operate at much lower flow rates than classical demisters, often in vertical orientation, with much finer geometries, and gravity plays no direct role for entrainment. We present a novel combination of four measurement techniques used to capture the entrained oil drop spectrum from filters during operation in the size range of 0.01–2400µm. The diameter range below 10μm combines two established real-time methods including an electrical mobility particle spectrometer (EMPS; <1μm) and an optical particle counter (OPC; 0.3 to 10μm). The diameter range above 170μm is covered by a newly developed “large drop detection system” (LDDS) based on single particle light scattering. OPC and LDDS continuously count and classify all drops originating from the entire filter coupon with a time resolution of 1min. The EMPS was operated intermittently, following brief switches from aerosol to clear air flow. Drops in the size range between OPC and LDDS were collected and sized by an off-line method.This measuring system was applied to two representative types of glass microfiber media operated with oil mist generated from compressor oil, in order to characterize time resolved drop formation rates and spectra in the range of nanometers to millimeters. Wettable and non-wettable filter media were found to show similar entrainment characteristics, each with multi-modal drop spectra having two pronounced peaks in the ranges of 1–2μm and 200–300μm, respectively. During steady-state operation both modes were generated quasi-continually, the large drops at the rate of a few drops per hour and cm2 of filter surface, the micron size drops 103–104 times more frequently. Available indirect evidence suggests the same underlying entrainment mechanism for both types of fibrous media, namely the break-up of air bubbles formed periodically on the oil that drains on the downstream filter face. Direct detachment (blow-off) of large drops is unlikely at the prevailing operating conditions.

The method of additives in devising a gas chromatographic method to determine ionol and water in energy oils

The paper presents the results of devising a method of extraction and gas chromatography for determining the content of ionol and waterin petroleum energy oils (transformer, turbine, compressor, and engine oils). The research was aimed at higher accuracy and fidelity of the methods of extraction and gas chromatographic determining of antioxidant additives (ionol and water) concentration in petroleum energy oils. This could be achieved through a comparative trial of the analyzed energy oil by the method of adding definite amounts of ionol and wateras their solutions in respective liquid extractants. Meanwhile, the extractant added to the working sample of the analyzed energy oil must be ionol-free, and the content of the dissolved water must be minimal at the absence of free water. We have identified the conditions for performing extraction and gas chromatography measurements. If the analyzed energy oil contains free water before identifying the ionol content, the oil is centrifuged for water separation and further dried with silica or sodium sulphate. The identified component is extracted from energy oil within 2 to 5 hours in the temperature range of 18-30 0 С with stabilized temperature deviation range of no more than ± 2 0 C. Ionol is extracted from energy oil at the value of the “acid number” indicator of less than 0.1 mg of KOH per 1 g of the analyzed energy oil. If the “acid number” indicatoris higher, the energy oil is subject to preliminary silica purification for reducing the indicator value. After the purification, the “presence of water-soluble acids” indicator must have a “lack of water-soluble acids” characteristic at рН = 6.0-8.0 for the aqueous extract from the purified energy oil. While determining water content in energy oil, the liquid extractant and water must be mixed at a room temperature and in any ratio without segregation. The devised methods of measurements allow determining the analyzed components within one trial of energy oil with the use of one gas chromatograph equipped with evaporators, thermal conductivity detector, and a flame ionization detector. The devised methods can be applied to determine ionol and water concentration in fresh, maintenance and regenerated energy oils for monitoring their quality indicators.

Comparison Of The Powers Of Energy Losses In A Variable Capacity Displacement Pump Determined Without Or With Taking Into Account The Power Of Hydraulic Oil Compression

Abstract Powers of energy losses in a variable capacity displacement pump are compared with or without taking into account the power of hydraulic oil compression. Evaluation of power of liquid compression in the pump was made possible by the use of method, proposed by the Author, of determining the degree of liquid aeration in the pump. In the method of determining the liquid aeration in the pump and of powers of volumetric losses of liquid compression a simplified formula (qPvc × ΔpPi)/2 was used describing the field of indicated work of volumetric losses qPvc of liquid compression during one shaft revolution at indicated increase ΔpPi of pressure in the chambers. Three methods were used for comparing the sum of powers of volumetric losses ΔPPvl due to leakage and ΔPPvc of compression and also ΔPPm|ΔpPi of mechanical losses resulting from increase ΔpPi of indicated pressure in the working chambers.

Development of a Committee of Artificial Neural Networks for the Performance Testing of Compressors for Thermal Machines in Very Reduced Times

Abstract This paper presents a new test method able to infer - in periods of less than 7 seconds - the refrigeration capacity of a compressor used in thermal machines, which represents a time reduction of approximately 99.95% related to the standardized traditional methods. The method was developed aiming at its application on compressor manufacture lines and on 100% of the units produced. Artificial neural networks (ANNs) were used to establish a model able to infer the refrigeration capacity based on the data collected directly on the production line. The proposed method does not make use of refrigeration systems and also does not require using the compressor oil.

Position Control of Hydraulic Actuators Using Fuzzy Pulse Width Modulation (PWM)

Hydraulic actuators are widely employed for industrial automation for its high power over weight ratio, functionality in tough operating conditions and low cost. However, the dynamics of hydraulic systems are non-linear and the system subjected to non-smooth and discontinuous non-linearities due to directional change of valve opening, friction, valve overlap and changes of hydraulic pressure acted on valve spool. Taking into account the effect of nonlinear parameter variations such as bulk modulus, compressibility of oil or viscosity of oil, fuzzy logic approach is chosen. Fuzzy control can adapt the inconstant working condition and non-linear system alongside of its robustness. For PWM controlled hydraulic component such as solenoid valve, effective approximation of the flow properties in a solenoid valve is essential. In this paper, the effect of fuzzy logic approach incorporated on pulse width modulation (PWM) controlled hydraulic system is to be investigated and experimentally verified.

Mathematical Model Defining Volumetric Losses of Hydraulic Oil Compression in a Variable Capacity Displacement Pump

Abstract The objective of the work is to develop the capability of evaluating the volumetric losses of hydraulic oil compression in the working chambers of high pressure variable capacity displacement pump. Volumetric losses of oil compression must be determined as functions of the same parameters, which the volumetric losses due to leakage, resulting from the quality of design solution of the pump, are evaluated as dependent on and also as function of the oil aeration coefficient Ɛ. A mathematical model has been developed describing the hydraulic oil compressibility coefficient k lc|Δppi;Ɛ;v as a relation to the ratio ΔpPi/pn of indicated increase Δp Pi of pressure in the working chambers and the nominal pressure pn, to the pump capacity coefficient bP , to the oil aeration coefficient  and to the ratio v/vnof oil viscosity v and reference viscosity vn . A mathematical model is presented of volumetric losses q pvc |ΔpPi;bp;;vof hydraulic oil compression in the pump working chambers in the form allowing to use it in the model of power of losses and energy efficiency

Determination of the continuous stress-dependent permeability, compressibility and poroelasticity of shale

The continuous changes of the stress-dependent permeability, compressibility and poroelasticity of a tight oil and gas shale were characterized by using the Constant Rate of Strain (CRS) consolidation test. The CRS consolidation test compresses a thin disk test specimen at a given constant rate of strain under one-dimensional consolidation with one-sided drainage condition and measurement of excess pore pressure at the undrained end. Permeability is calculated from the one-dimensional consolidation equation assuming oedometric loading, incompressible solid grains, and an idealized excess pore pressure distribution in the sample. The CRS test method has been widely used for the determination of the stress-dependent permeability of soft sediments, but has not been utilized for very stiff and low permeability shale as well as to obtain their stress-dependent compressibility and poroelasticity parameters. To test its appropriateness to shale, CRS tests were performed on thin disk samples of Mancos shale using a high pressure and high temperature triaxial cell under high isotropic confining stresses. Two modifications were done to make the CRS test applicable to determination of the continuous stress-dependent hydro-mechanical properties of tight shale: (1) the test method was modified for isotropic loading, and (2) nonlinear poroelastic effects were accounted for in the solution of the pore pressure dissipation equation. The permeability values from the CRS tests with the modified analytical solution were found to be in agreement with those obtained from the Constant Pressure Gradient Permeability test, and Pressure-pulse Decay Permeability test using nitrogen as pore fluid and corrected for Klinkenberg and non-Darcy flow effects.

РОЗЧИНИ ХОЛОДОАГЕНТ/КОМПРЕСОРНЕ МАСТИЛО: ПРОБЛЕМИ ЗАСТОСУВАННЯ ТА ДОСЛІДЖЕННЯ ВЛАСТИВОСТЕЙ

The results and generalizations of thermophysical property research for the refrigerant/lubricant mixtures are summarized. The methodological aspects of the experimental studies of the thermal properties of real working media for vapor compression refrigeration machines and the general principles of the thermodynamic properties simulation for such solutions are analyzed. It is shown that the admixtures of compressor oil in the refrigerant make the efficiency parameters of compressor systems much lower. The question of a selective solubility of the multicomponent refrigerants in compressor oils is discussed.

Position control of hydraulic servo system using proportional-integral-derivative controller tuned by some evolutionary techniques

This paper uses a particle swarm optimization (PSO) algorithm, an adaptive weighted PSO (AWPSO) algorithm, and a genetic algorithm (GA) to determine the optimal proportional-integral-derivative controller’s parameters of a hydraulic position control system. A typical hydraulic servo system has been selected as an application. The mathematical model of this hydraulic servo system which comprises the most relevant dynamics and nonlinear effects is considered. The model simulates the behavior of a REXROTH servo valve and includes the nonlinearities of friction forces, valve dynamics, oil compressibility, and load influence. The performance indices, which have been used in the optimization process, are integral absolute error, integral square error and integral time absolute error. The proposed controller is implemented on the simulation model to identify the best method for tuning the controller. Compared with GA and AWPSO results, the PSO method has been found to be more efficient and robust in improving the step response of a position control for hydraulic systems in terms of settling time, maximum overshoot and undershoot.

OPTIMIZATION OF BASIC INSTALLATION OF DEASPHALTIZING OF TAR

Deasphaltizing of oddments by oil hydrocarbon solvents is applied to selection of lube cuts of oil for a long time. At their afterpurification they are applied as a basis for production of engine, aviation, cylinder, compressor, transmission and other oils. One more purpose of process of deasphaltizing is a preparation of high-polymeric fractions of oil to deep recycling by processes of hydrotreating and catalytic cracking. In recent years increase in prices for many energy resources, such as natural gas, water vapor, electric power and the others. Besides, high deterioration of inventory at the enterprises demands padding expenses. All this in a complex with sluggish rates of modernization of technological processes leads to rise in price of production of oil processing and decrease in its competitiveness in the world and domestic market. Account indexes of power supplies for processing of 1 ton of raw materials by deasphaltizing processes is defined by degree of perfection of flow diagram, inventoriesand quality of the processed raw materials. In article advantage of a revitalization system of solvent in supercritical conditions with two-stage injector system of a compression of gases of low pressureover the basic scheme of installation is considered, that allows to lower energy consumption and quantity of metal-consuming equipment for carrying out process and increases flexibility of technological process. At solvent recovery in supercritical conditions of division the economy of energy resources for 25-50% in comparison with the standard scheme of solvent recovery is reached. The scheme which can be realized on the installations of deasphaltizing of tar working as by oil option with use of propane solvent and by fuel option with use as solvent propane - butane mixes is offered.

Dynamic Performance Study of Stewart Parallel Mechanism Based on Natural Frequency

The stiffness of transmission mechanism, assembled joints and moving platform, the compressibility of oil, and the load inertia of hydraulic Stewart mechanism will cause synthetically mechanical and hydraulic resonance problems, which will directly influence the system dynamic performance. The natural frequency and local dynamic isotropy index are adopted to evaluate dynamic performance. The variation trends of performance indices with configuration and inertia parameters are analyzed, and general optimal design rules and conclusions are obtained.

A New Way to Eliminate the Phenomenon of Trapping Oil in Gear Pumps

The phenomenon of trapping oil is an inevitable result to ensure oil absorption cavity and oil exhaust cavity are not collude with each other. It directly affects the working performance and service life of the gear pump. This article through analyzing the root cause of it put forward a new way to using an external oil circuit to eliminate it. Adding such an external oil circuit to the gear pump, can make the dead volume linked to oil exhaust cavity when the dead volume is decreasing and make the dead volume linked to oil absorption cavity when the dead volume is increasing. This way eliminates the trapped oil compression and expansion, so as to achieve the purpose of thoroughly eliminate the phenomenon of trapping oil.

Undersaturated Oil Compressibility Prediction for Mishrif Reservoir in the Southern Iraqi Oil Fields Using Artificial Neural Network

Coefficient of Isothermal oil compressibility is required in transient fluid flow problems, extension of fluid properties from values at the bubble point pressure to higher pressures of interest and in material balance calculations [1, 2]. Coefficient of Isothermal oil compressibility is a measure of the fractional change in volume as pressure is changed at constant temperature [3]. Coefficients of isothermal oil compressibility are usually obtained from reservoir fluid analysis. Reservoir fluid analysis is an expensive and time consuming operation that is not always available when the volumetric properties of reservoir fluids are needed. For this reason correlations have been developed and are being developed for predicting fluid properties including the coefficient of isothermal oil compressibility.&#x0D; This paper presents an application of Artificial Neural Network (ANN) methods for estimation of isothermal oil compressibility for the Mishrif reservoir oils among of commonly available field data, according to the fact that this method is useful when relationships of parameters are too complicated. The method is proposed as a more effective prognostic tool than are currently available procedures.&#x0D; In this study, back propagation (BPN) network was used to develop an ANN model to predict isothermal oil compressibility. A three layer feed-forward network has been selected which has the best correlation coefficient in testing the models. The new model of undersaturated oil compressibility in which the first layer consists of five neurons representing the input values of pressure above bubble point, solution gas oil ratio at bubble point, oil gravity API, reservoir temperature and gas specific gravity. The second (hidden) layer contains 12 neurons, and the third layer contains one neuron representing the output values of undersaturated oil compressibility. It was found that the new model estimate undersaturated oil compressibility for Mishrif reservoir crudes in the southern Iraqi oil fields much better than the published ones. The present model predicts undersaturated oil compressibility with an average absolute relative error of 3.86% for the testing data set.

Experimental Study on the Compressibility of Gelled Crude Oil

Summary The compressibility of gelled crude oil is crucial for the restart behavior of a pipeline. However, only a few reports have been published in this field. In this paper, experiments were conducted for the compressibility of waxy crude oil at temperatures lower than pour point. Results show that the compressibility of gelled crude oil is much higher than that of the liquid oil at temperatures above pour point. The compressibility characteristic curve of gelled crude oil is obtained in this research, which shows that the compressibility of gelled crude oil will gradually decrease during the compression process until the gel structure is completely destroyed and the void space is compacted.

Experimental Investigation and Thermodynamic Modeling of the Phase Behavior of Reservoir Fluids

An experimental study and thermodynamic modeling was conducted to quantify the phase behavior and physical properties of an Iranian crude oil sample. The oil sample was compositionally characterized by the distillation technique. Also, differential liberation tests and flash were conducted on an oil sample. Experiment results for phase behavior and reservoir fluid properties were used to evaluate the reliabilities of three cubic equations of state, including Peng-Robinson, Pate-Teja, and Soave-Redlich-Kwong for predicting flash calculation, and differential liberation test simulation of Iranian crude oil. Results show that heavy components in the petroleum mixtures based on the comparisons with the experimental data have the strongest effect on the characteristics of the fluids. It is obvious that Pate-Teja equation is superior in the calculations composition gas phase in higher pressure. Also, flash calculations based on Pate-Teja equation in the case of lumping is more accurate than results obtained by Peng-Robinson and Soave-Redlich-Kwong equations. Comparison of predicted oil specific gravity, gas oil ratio, relative volume, and compressibility factor of the liberated gas based on Pate-Teja equation to experimental data shows a better agreement than other equations. It should be noted that modeling of the gas oil ratio and relative volume has better agreement with experimental data in higher pressure.

Prediction of the surface tension for refrigerants and refrigerant-oil solutions (ROS)

This paper presents an approach for prediction of the surface tension of refrigerants and refrigerant-oil solutions (ROS). A new universal relationship between the surface tension and saturated vapor pressure has been developed. Proposed model was validated for saturated hydrocarbons, hydrochlorofluorocarbons (HCFCs), hydrofluorocarbons (HFCs), chlorofluorocarbons (CFCs), dimethyl ether (R-E170), mineral and polyolester compressor oils and its solutions. We propose to relate the experimentally obtained data on surface properties for the ROS to the effective concentration of the refrigerant in the surface layer of the solution.

Assessment of Waste Production and Heavy Metal Emission from Energy Production Sector of Zahedan City

Background and purpose: Due to the lack of accurate statistics on the amount of waste generated in the energy production sector in Zahedan, before any planning, one should identify all waste producing centers associated with the energy sector and also the quantity and quality of their waste in Zahedan. Materials and Methods: This research is a cross-sectional descriptive study. It examined the produced wastes in the electrical energy generation sector. A questionnaire was prepared and completed for each unit that possibility produces these wastes. Moreover, in the studied units, the weigh percent per unit was determined by separating production waste, and collecting and weighing them. Results: In gas power plant of Zahedan, production of burned oil was approximately 480 liters and the annual consumption of turbine oil and compressor oil was 40 liters. In the diesel power plant, 2,200 liters of burned oil is produced for each generator after 1,500 hours of work. Concentration of heavy metals of Cr, Cd, Zn, Pb, Cu, and Ni in the burned oil sample of the gas power plant was 43.2, 0.01, 0.20, 1.3, 2.7, 0.2 mg/l, respectively; and in the diesel power plant were 36.3, 0.08, 0.09, 0.9, 4.7, 1.1 mg/l. Conclusion: In the studied samples, several cases of heavy metal pollution were identified. Therefore, proper planning for appropriate management of these units is necessary for any possible leakage and environmental pollution transport. Furthermore, in order to minimize the adverse impacts of hazardous wastes on the environment and people in Zahedan, integrated hazardous wastes management should be practices in electrical energy generation plants. Moreover, one must consider the measures required to exposure, transport, and safe maintenance before managing or eliminating this type of waste. [Poormollae N.*Bazrafshan E. Nasrabadi M. Assessment of Waste Production and Heavy Metal Emission from Energy Production Sector of Zahedan City. IJHS 2013;1(3):51-57] http://jhs.mazums.ac.ir