Development of an accelerated test for pitting corrosion of CUSTOM 450 by rDHM

A key application of CUSTOM 450 alloy is in the construction of gas turbine compressor blades. The study of pitting corrosion can prevent the failure of many gas turbine compressor blades. In this study, a reflective digital holography microscopy method was employed to investigate the growth of pitting corrosion in depth. To this end, a constant potential of 350 mVSCE in a 3.5 wt.% NaCl solution was applied to the specimen. The generated pits were simulated in three dimensions, and it was indicated that pitting corrosion rate was decreased as time passed. Comparing the obtained experimental data with the data gathered from the real industrial environment surrounding a compressor installation, an accelerated test was proposed. By the proposed accelerated test, it is possible to produce a pit similar to the one that will be initiated and propagated at any time in the future in real conditions.

ADJUSTMENT OF FUZZY ADAPTIVE REGULATOR OF COMPRESSOR UNIT FOR LIQUEFACTION OF NATURAL GAS

The main properties of the object are studied, as well as the methods by which new parameters can be found for the regulator of the compressor unit for liquefaction of natural gas. The main properties of the adaptive regulator itself are studied, as well as the method by which the work was performed is developed. A comparison was also made with other types of automatic control systems that can be used in this facility. The sequence of construction of the adaptive controller and its interaction with the object is studied. The initial results of the adaptive controller and their comparison with other automatic control systems are investigated. The general properties and rules of construction of the adaptive regulator, the basic subtleties at work with it are studied. New possibilities for regulation of the compressor installation for liquefaction of natural gas are fully considered and the basic rules concerning application of this adaptive regulator are deduced. A study of the effectiveness of the adaptive regulator for this object was conducted and conclusions were made on the work of the regulator and the effectiveness of its results. A special sequence of work was also developed for the construction of an adaptive controller and its application on site. In general, the basic rules for working with such a regulator and its application in a natural gas liquefaction plant are derived. The behavior of the plant is investigated and new settings for the regulation of the natural gas liquefaction plant are derived. The main types of regulation of this object are applied and new rules for finding settings for the main regulator of the compressor unit are derived. The work on comparison of already traditional types of regulation with the adaptive regulator is made and conclusions on application of this or that type of regulation of compressor installation comparing results of regulation are made. The possibility of real use of this regulator on a constant basis in production is investigated, conclusions on the main work of the regulator and also shortcomings which can arise at a choice of regulation with the adaptive regulator are made.

Comparative stochastic analysis of the anomalous dynamics of machines under the action of operational defects

The possibility of increasing the confidence of vibroacoustic diagnostics of the technical condition of rotor-type machinery is being investigated. The search for additional sensitive and reliable features is based on the analysis of two-dimensional probability distribution densities of vibration amplitudes. This approach allows to assess the degree and character of the nonlinearity of the machine dynamic model as an oscillatory system. An example of diagnosing the technical condition of a compressor installation is given, showing the possibility of an indirect operational assessment of the accomplished repair. Keywords vibroacoustic diagnostics, nonlinear oscillations, stochastic connection, sliding bearing, defects. [email protected]

DEVELOPMENT OF A MATHEMATICAL MODEL OF A COMPRESSOR UNIT FOR NATURAL GAS LIQUEFACTION

First of all, such a topic as compressors for liquefaction of natural gas is unfortunately not very well studied. Therefore, this publication will present a detailed study of this object. First of all, the object itself will be considered, what it consists of, what its properties are, how natural gas liquefaction processes take place in it. So first you need to fully study the object itself, and only then proceed to build its mathematical model, which in the future can be used for more detailed analysis, first theoretically and then for practical purposes. This will achieve great results in the construction of an automatic control system for the compressor for liquefaction of natural gas. So, first the object itself will be studied, and only then, based on the acquired knowledge, we will build a mathematical model that will be needed in the future to develop an automatic control system. Of course, if you do not fully study all the properties of the object, such as the physical processes that take place there and the properties of the compressor. And having already put together all the available information, we can have a complete picture of this object. And from this information that has been collected, we can finally move on to the development of a more detailed mathematical model, which will be, albeit simplified, but still close to reality. Only then, already having this mathematical model, you can move on to a more detailed study in theory. And after conducting theoretical research, it is possible to check all the results of the study on a mathematical model, which will help to understand whether they are effective. Because it is more profitable to check theoretical information on a mathematical model than to do it on a real object. This can be costly, and in the case of an installation such as a natural gas liquefaction compressor, it is very expensive. And therefore this mathematical model will be appropriate. This model can be used in a more detailed study of this object because at the moment there is no holistic picture for the dagono object. It will also be possible to apply this model to find the necessary laws of regulation which will help to increase productivity of the compressor installation for liquefaction of natural gas. And this model will help to solve this question and to establish full-fledged work on studying of the given compressor installation.

Transient Operation in Pipeline Compressor Stations

Many pipelines are not operated under steady state conditions. This is in particular true for pipelines that are highly integrated with other pipelines, or have many different feed or gas take-off points. In many cases, the demand changes frequently, and cannot always be planned with a long time horizon. In this study, a simplified transient pipeline model, together with a high fidelity model of a compressor installation and its control system are used to evaluate control strategies that can optimize the fuel consumption and reaction time in these transient situations. The model for the compressor installation contains an accurate representation of the compressor and driver performance, together with the capability to simulate different, but realistic control strategies. This allows specific and general recommendations on the use of control algorithms.

Designing Compressor Installations for Reliability

This paper discusses and illustrates how the application of analytical tools, if properly applied, during the design process ensures a design that is both reliable and economic. Emphasis is on the dynamic behavior of centrifugal and reciprocating compressors. Illustrations deal with both types of compressors. The key requirement is that pulsations, vibration levels and dynamic stresses must be low enough, that there is minimal impact on performance or reliability, while maintaining an economical design. To achieve this result, it is necessary to understand and control forcing functions, natural frequencies, mode shapes and dynamic stiffnesses. These considerations apply to rotor dynamics, piping vibration, torsional vibration, skid and foundation vibration. In addition, similar considerations apply to gas pulsations, where the interaction of the piping geometry with pressure pulsations, (arising from the uneven flow of gas through the suction and discharge nozzles), can produce significant forces and stresses for both reciprocating and centrifugal compressors, as well as degradation of performance. Computer modeling can be used to avoid problems that reduce reliability, degrade performance and increase maintenance. Considerations for determining the appropriate level of analysis are outlined. The probability and cost of events in the absence of suitable design are discussed. The cost of these events is compared to relevant design costs. The practical implications are illustrated with three cases where adequate design modeling and optimization was not done. One case involves a lateral critical and a structural resonance in a centrifugal compressor installation. The second involves a piping failure in a reciprocating compressor installation. The third involves a torsional failure in a reciprocating compressor installation.