Tag Archives: газоперекачивающий агрегат
The article deals with reliability assessment of gas pumping units of the gas pumping system of Russia by the GTC-10 as example. The park structure of gas pumping unit types is presented. It is shown that the aggregates of this type are of the very large group of gas pumping equipment.
It has been established that a significant part of gas pumping units is worn-out. About 8% of GPA worked more than 100 thousand hours, 45% – 50÷100 thousand hours. By the example of one of the subsidiaries of PJSC “Gazprom” the analysis of quantitative indicators MTBF GTC-10 are done. The empirical reliability function, the density of developments units to failure after major repairs distribution, the failure rate are built.
According to the renovated GPA parameter “the failures distribution density” the kind of the distribution law is determined. It is shown that it is the law of the Weibull distribution.
Analysis of statistical data on the operation of gas pumping units showed that the entire life cycle of work can be divided into three characteristic regions – running, normal operation, the period of wear and aging. For each time period, the Weibull distribution parameters are defined and presented in tabular form.
In the end of the article the conclusions about an increased failure rate of GPA at the equipment running and aging steps are done. The identification of patterns is recommended to be taken into account when planning repairs, vibration surveys and findings of gas pumping units in reserve.
DEFINITION OF ENERGY EFFICIENCY INDICATORS OF GAS TRANSFER UNITS WITH APPLICATION OF NEURAL NETWORKS
When operating gas transfer units with gas turbine drive a significant share (about 9%) of natural gas is spent on compressor stations own needs.
A considerable expense of pumped gas for gas transfer units own needs at compressor stations determines the actuality of realization of resources saving technologies. When performing energy saving measures it is required to control the resulting effect.
Control of energy consumption is based on energy efficiency indicators of gas transfer units which include efficiency and gas fuel rate.
The aim of this paper was to develop a universal method of calculating energy efficiency indicators using intelligent methods which exclude risks of reducing accuracy of results.
In this paper we proposed and justified method of calculating energy efficiency indicators on the base of monitored parameters of gas transfer units work with application of neural networks.
The research made it possible to receive and to substantiate the method of determining the specific consumption of fuel gas by the parameters of HPA controlled standard automation system based on the application of intelligent neural networks.
Neural network model can be integrated in the station monitoring system compressor station need only advance to pick up army of weights to train a neural network) for a particular type HPA.
When training a neural network according to the variation of the parameters in the training set and 20% teaching error does not exceed 1%. When using neural networks for the calculation of energy efficiency indicators for the unit for which there was training for other units of the same type, the mean square error does not exceed 5%.
The main gas pipelines are the body of the gas transmission system. The main share of expenses of energy resources in the pipeline transport of gas belongs to this part of the system. Characteristics of the pipeline network, also as the set technological tasks, are defining factors for an operating mode of other equipment of system which settles down generally at compressor stations.
In this regard, it is very important to provide possibility of calculation of an operating mode of the main gas pipeline with sufficient degree of accuracy. For this purpose you have to consider all significant factors which influence operation of the main gas pipeline. The method of calculation shouldn’t contain insoluble difficulties of mathematical character.
In spite of the simple construction of the gas pipeline at first sight, it contains difficult processes of movement, friction, interaction with gravitation, internal and external heat exchange. These processes, as a rule, change in time therefore they are non-stationary.
The gas transmission system has the difficult scheme where simple gas pipelines are united in a transport network, the operating mode of all elements is interconnected.
The specified complexity of processes has rather difficult mathematical description of all these processes by means of the corresponding models, in this regard; obtaining decisions is accompanied by difficulties of mathematical character. Simplification of models for the avoidance of the specified difficulties can reduce their compliance to the described object.
The author of this work considers existing methods of calculation of simple gas pipelines, does their analysis.
The author classifies models concerning a scope.
The author revealed construction stages for all considered universal models.
By results of the research the author draws a conclusion about the necessity of the solution of the question of mathematical modeling of gas movement in the main gas pipeline and notes the productive directions of further researches of this subject.
IMPROVED RESISTANCE OF NICKEL AND COBALT ALLOYS NOZZLE BLADES BLOCK OF TURBINES TO THERMO-MECHANICAL LOADS
Improvement of performance characteristics of the most critical parts of hot tract gas turbine plants of gas compressor units is an urgent problem of the modern turbine construction. One such detail includes the guide vanes, turbine gas turbine units. Blades during operation, impacts are significant dynamic and static loads, high temperatures and thermo-mechanical loads, as well as corrosive and erosive destruction. Proceeding from the requirements for the manufacture of gas turbine blades are applied heat-resistant and heat-resistant nickel and cobalt. Replacement during repair of the damaged turbine blades is time consuming and expensive process. Development of new technologies of protective and strengthening processing of turbine blades, providing increase of their resource, is a task which can save a considerable material and financial resources. However, one of the goals of protective and strengthening processing of parts is modernization of blades, which moves on a higher level of quality.
Currently used cooled nozzle blades during operation damaged in the result of occurrence of defects in the form of cracks. Research has shown that one of the main causes of cracks, along with the processes of thermal fatigue, creep of the material degradation and oxidation processes, is the emergence of a significant thermal stresses between the block elements in the result of difference of temperatures. The temperature difference between block elements linked c uneven removal of heat from the top and bottom shelves, as well as from the pen of the blade.
In this article we propose a method of increasing resistance of components of gas-turbine units of gas pumping units due to compensation of thermo-mechanical stresses on the blades. This method is based on use of the principle of selective thermal insulation of components of nozzle segment, which is implemented based on a technology, developed by authors, for thermo-barrier coating (TBC) application. Detailed development of selective thermo-barrier coating and its application was used on HPT gtk-10I segment. Thermal-barrier ceramic layer was applied on the external surface of the block bottom and airfoils, as well as on the transition area in between the block top and airfoils. Using the proposed coating and the technology of its application increased blade life by 1.4 – 1.7 times, which saves material and financial resources and ensures the proper level of efficiency and reliability of gas pipeline transportation systems.
The author of this work offers the way of definition of the internal calculating error of methods of the gas pipeline hydraulic calculation. The offered way is applicable both to stationary model, and to the most general case – to the model describing non-stationary process. This way is shown on the calculation of the known system of the equations which describes non-stationary process by “the way with variable coefficients”. But this way of calculation was considerably modified by the author for the accounting of heat exchange, and for gravity influences. But this way of calculation was considerably modified by the author for the accounting of heat exchange, and for gravity influences. The initial “way with variable coefficients” didn’t consider these factors that attracted considerable errors. The mentioned adjustment is described in detail by the author in the other publication. The offered way of definition of the internal calculating error of methods of the gas pipeline hydraulic calculation includes the analysis on each component of the initial equation of movement of compressed liquid. The author gives formulas for definition of influence of all factors entering this equation. The main thing of definition of an internal calculating error is the comparison of the sum of influence from all factors which sizes are received as a result of calculation for the chosen method with basic data for the same calculation. These data are provided to a uniform scale for possibility of carrying out procedure of comparison. As such scale the size of change of gas pressure in the course of its movement on the gas pipeline is accepted. The author defines changes of pressure according to the following factors: change of gas energy in volume because of not stationarity of process, change of kinetic energy of gas, influence of friction forces and weight. The sum of changes of all these factors pressure is compared with the general pressure difference on the gas pipeline that is set in basic data of calculation. Their distinction defines an internal calculating error of the estimated method. The offered way is shown on calculation of the concrete example. The author shows settlement ratios for all counted parameters, and results of calculation, are presented by numbers or graphically for the offered example.