Fuel distributor control of an internal combustion engine using Hilbert-Huang transformation

Article purpose: to consider the possibility of Hilbert-Huang transformation (HHT) use for vibration-acoustic control of a fuel dispenser operation in an internal combustion engine HHT was proposed by Norden Huang in 1995 to study the surface waves of typhoons. In recent years, the method has been actively used in geophysics, medicine, radio engineering, etc. Hilbert-Huang transformation makes it possible to extract information from signals about the rapid temporal changes of their spectral composition. HHT is the method of empirical mode decomposition of signals and Hilbert spectral analysis.The article presents the results of vibration-acoustic signal processing of an internal combustion engine using HHT. The series of experiments was carried out in a test laboratory on a motorized bench (eight-cylinder two-stroke engine). The measurements of vibrationacoustic signals were carried out for the periods when the engine operates in normal mode and when one of the cylinders is not working (the supply to the fuel dispenser is switched off). It was determined that the 9th empirical mode (Intrinsic mode functions) contains the basic harmonic components of a signal. When the fuel dispenser of one of the cylinders is disconnected, the asymmetry of the instantaneous frequencies distribution of the 9th IMF appears relative to their average value. During the analysis of their central third-order moment, it is possible to establish the state of the controlled object properly.Keywords: Hilbert-Huang transformation, empirical mode decomposition by ensemble, instantaneous frequency, third-order central moment, nondestructive testing, internal combustion engine, vibration-acoustic signa

Neural network analysis of vibration signals in the diagnostics of pipelines

The article is devoted to the improvement of heat network calculation and diagnostics methods. Currently used instruments have many shortcomings for the diagnosis of pipelines, including low reliability of defect detection and subjective decision-making. The authors created an experimental stand, which allows to conduct the diagnostics of pipelines by a vibration-acoustic method. They studied steel pipes filled with water, the surface of which 50x50 mm defect and the depth of thinning of 2 mm, 3 mm, and 5 mm. Using the vibrationacoustic sensors fixed on an outer surface, the vibration signals generated by the water flow in the pipe were obtained. In order to process the large volumes of data obtained as the result of experiments, it is proposed to use artificial neural networks. Among all considered types of neural networks, the authors prefer Kohonen's networks due to the best effectiveness of a defect determination. The program for an acoustic signal processing and analyzing through a neural network was implemented in LabView 8.5 work environment. Depending on the accuracy of a problem being solved, and the details of a training sample, the program is able to produce the results of sample classification of samples for a defect-free and defective pipes of different depth of damage. The results of the classification by Kohonen's trained neural network show good abilities for the analysis of unknown samples and a high degree of their recognition reliability.Keywords: diagnosis, corrosion, defect, pipelines, acoustic signal, neural networ

The influence of catalysts on the combustion of petroleum coke in the stationary fluidized bed mode

It is known that petroleum coke, a product of deep processing of oil, can be used as fuel in power boilers. The method of petroleum coke burning in a fluidized bed is the most optimal to complete its combustion. To improve the combustion characteristics of this fuel, we studied the influence of catalysts on the petroleum coke burning in the simulation mode of a stationary fluidized bed. The laboratory setup is described. The results of the experiments are given

Petroleum coke combustion in fixed fluidized bed mode in the presence of metal catalysts

© 2020 American Chemical Society Petroleum coke is one of the waste products generated in the oil refining industry that can be used as fuel in energetics. However, the low volatile matter content and graphite-like structure of petroleum coke are the reasons for its high ignition temperature and combustion complexity. In this research, petroleum coke combustion and oxidation kinetics in the presence of metal catalysts were investigated. To evaluate the effect of the catalyst on the ignition temperature and the apparent activation energy, a new approach of a “fixed fluidized bed” was proposed. In this mode, petroleum coke particles spaced from each other by inert quartz powder kind of “freeze” in the porous layer. This regime allows us to determine the ignition temperature of petroleum coke particles in the static mode by differential thermography and calculate the activation energy by gas analysis. Organic and inorganic salts of copper, iron, and cerium are used as catalysts for petroleum coke combustion. A series of experiments were carried out in the porous media thermo-effect cell (PMTEC) and on a thermogravimetric (TG) analyzer. The kinetics of the combustion processes was calculated by Kissinger−Akahira−Sunose and Ozawa−Flynn−Wall methods. The results obtained in the “fixed bed” mode showed that the ignition temperature and the average apparent activation energy significantly decreased in the presence of CuCl2 and FeCl3. The results obtained by the new approach were compared with the results of the thermogravimetric analysis

Study of the efficiency of gel and polymer-stabilized foam systems for gas shut-off in horizontal wells

This article describes the assessment of effectiveness of gel and foaming agents for gas shut-off treatments in horizontal wells. The research is carried out through the implementation of a complex of special laboratory studies and analysis of the results using numerical modeling methods. A list of necessary laboratory experiments to minimize risks when carrying out work to limit gas inflow has been formulated, and approaches to carrying it out have been described. The program includes: free volume studies, filtration on linear and parallel core models. The results confirm the importance of studying not only the agent's physical characteristics at the reservoir conditions, but their interaction with reservoir fluids. The influence of different agents on the mobility of gas and oil was assessed as a result of linear core flooding experiments. In addition, the filtration tests on parallel cores were carried out aimed to determining the saturation selectivity. The series of numerical calculations was performed for the subsequent determination of the technological and economic effects of the treatment with gas blockers

Low-temperature combustion characteristics of heavy oils by a self-designed porous medium thermo-effect cell

© 2020 Elsevier B.V. The combustion characteristics of two Xinjiang heavy oils were studied by the self-designed porous medium thermo-effect cell (PMTEC) that can monitor the temperature alterations caused by oxidation/combustion reactions occurring within a porous medium under dynamic air flow. The results indicated that the heavy oils encountered obvious low-temperature combustion (LTC) in the temperature range of about 280–360 °C, accompanied by a maximum temperature increase to roughly 600 °C and significant release of CO and CO2. Then, PMTEC was adopted to evaluate the effects of air injection rate and water saturation on crude oil combustion. The increase of the air injection rate was conducive to triggering the LTC reactions and enhancing the intensity of LTC. The highest air injection rate (1 L/min in this work) led to the occurrence of fairly intense LTC reactions, during which large amounts of oxygen and oil sample were consumed. The increase of water saturation produced a minor influence on the occurrence of LTC, but obviously weakened the intensity of LTC. In addition, the influence of four metallic salts on the combustion behavior of heavy oil was examined using PMTEC. Cobalt naphthenate exhibited the good catalytic effect for promoting the occurrence of LTC. The mixed catalyst (cobalt naphthenate + manganese naphthenate) was found to have a better catalytic performance than any used single metallic salt. This mixed catalyst has a good potential for application in in-situ combustion of the Xinjiang heavy oil

Nonylphenol ethoxylate surfactants modified by carboxyl groups for foam EOR at high-salinity conditions

High mineralization of water complicates the use of foam in reservoir conditions. Anionic– nonionic surfactants are one of the best candidates for these conditions since they have both high surface activity and salt tolerance. One of the ways to obtain anionic–nonionic surfactants is to modify nonionic surfactants by an anionic group. The type of the group and its chemical structure can strongly affect the properties of the surfactant. In this work, widely-produced nonionic surfactant nonylphenol (12) ethoxylate (NP12EO) was modified by new types of carboxylic groups through the implementation of maleic (NP12EO-MA) and succinic (NP12EO-SA) anhydrides with different saturation levels. The main objectives of this work were to compare synthesized surfactants with nonionic precursor and to reveal the influence of unsaturated bonds in the carboxyl group on the properties of the foam. NaCl concentration up to 20 wt% was used to simulate high mineralization conditions, as well as to assess the effect of unsaturated bonds on foam properties. Synthesized anionic–nonionic surfactants retained surfactant solubility and long-term stability in high-salinity water, but have better foaming ability, as well as higher apparent viscosity, in porous media. The presence of an unsaturated bond in NP12EO-MA surfactant lowers foaming ability at high mineralization

Laboratory studies for design of a foam pilot for reducing gas channeling from gas cap in production well in messoyakhskoye field

Messoyakhskoye field, operated by Gazprom Neft, is currently experiencing gas channeling from gas cap in production wells because of strong heterogeneity. Foam for a long has been considered as a good candidate for gas blocking, (Svorstol I. et al., 1996), (Hanssen, J. E., & Dalland, M. 1994), (Aarra, M. G. et al., 1996). However, foam injection for gas blocking in injection well is different from that in production well, where it is necessary to selectively and long-term impact on gas-saturated highly permeable areas without affecting the phase permeability of oil in the reservoir. This paper provides detailed laboratory studies that show how to determine suitable foam systems for gas blocking in production well. For gas blocking in production well, a long half-life time is required to sustain stable foam because a continuous shear of surfactant solution/gas can't be achieved like in injection well. Therefore, reinforced foam by polymer is chosen. Four polymer stabilizers and five foam agents were evaluated using bulk test to determine foaming ability, foam stability, and effect of oil by comparing foam rate and half-life time to determine the suitable foam system. Furthermore, filtration experiments were conducted at reservoir conditions to determine the optimal injection mode by evaluating apparent viscosity, breakthrough pressure gradient, resistance factor, and residual resistance factor. Polymer can significantly improve half-life time (increase foam stability), and the higher the polymer concentration, the longer the half-life time. But simultaneously, a high polymer concentration will increase the initial viscosity of solution, which not only decreases the foam rate, but also increases difficulties in injection. Therefore, an optimal polymer concentration of about 0.15-0.2 wt% is determined considering all these influences. Filtration experiments showed that the apparent viscosity in core first increased and then deceased with foam quality (the ratio of gas volume to foam volume (gas + liquid). The optimal injection mode is co-injection of surfactant/polymer solution and gas to in-situ generate foam at the optimal foam quality of about 0.65. Filtration experiments on the different permeability cores showed that gas-blocking ability of polymer reinforced foam is better in high-permeability cores, which is beneficial for blocking high permeability zone. It should be also noted that under a certain ratio of oil to foam solution (about lower than 1 to 1), the presence of oil slowly decreased foam rate with increasing oil volume, but significantly increased half -life time, which is favorable for foam treatment in production well. This work highlights the difference between foam injection for gas blocking in production well and injection well, and emphasizes the use of polymer reinforced foam. Moreover, this work shows systematic experimental methods for choosing suitable foam systems for gas blocking in production well considering different factors, which provides a guide regarding what kinds of foaming agents and polymer stabilizers should be used and how to evaluate them for designing a pilot application

Effect of copper stearate as catalysts on the performance of in-situ combustion process for heavy oil recovery and upgrading

Using copper stearate as catalysts, catalytic in-situ combustion (ISC) of heavy oil was studied by porous medium thermo-effect cell (PMTEC) and combustion tube experiments. Significant acceleration of combustion was observed in porous media in PMTEC when copper stearate was added. Copper stearate promoted fuel deposition and its combustion and made them occur easier in low temperature, thus shifting both low-temperature oxidation (LTO) and high-temperature oxidation (HTO) into lower temperatures, and even totally merge HTO into LTO in some conditions. We found that the promotion on fuel deposition by catalysts might be related to the change of H/C ratio in fuel. The improvement in the performance of ISC by copper stearate in combustion tube experiments mainly manifests in lower ignition temperature, lower H/C ratio, increased air/fuel ratio, higher oil recovery, and higher level of in-situ oil upgrading, which makes copper stearate a good candidate for catalyzing ISC in field application