Anti-surge System Research Articles

Cylinder-piston application for surge prevention and energy efficiency in an industrial compression unit

Compressions are prevalent in industrial applications and are notable for their substantial energy consumption. Therefore, the simulation and analysis of the compression process are essential for maintenance and energy conservation efforts. These systems are prone to potentially unstable surge conditions, necessitating the use of traditional anti-surge valves that result in considerable energy losses. Ensuring the near-optimal operation of these systems is critical to minimizing energy consumption.In this article, a conceptual framework for a cylinder-piston mechanism is delineated, intended for design and operation as an active surge control system. Additionally, a modular quasi-one-dimensional model is articulated for the transient simulation of an industrial compression system, which integrates models for both the anti-surge and active control systems. The manuscript presents a novel design, featured by a cylinder-piston system integrated with a robust controller, posited as a potential alternative to traditional anti-surge systems. The effectiveness of this design in expanding the operational envelope of the compression system and surge prevention is rigorously examined. Moreover, a thermodynamic model, grounded in the fundamental laws of mass, momentum, and energy conservation, is applied to each component of the system. Furthermore, the manuscript explores the benefits of the innovative design in achieving a marked decrease in energy wastage. Simulation results from a test scenario reveals that the implementation of the cylinder-piston design, as opposed to the conventional anti-surge system, can diminish energy losses and associated pollutant emissions by approximately 33 percent.

Advantages and Disadvantages of Connect Anti Surge System Gas Pipe of Multistage Centrifugal Recycle Gas Compressor with Process Heat Exchanger in Power Former Unit in Daura Refinery

Advantages and Disadvantages of Connect Anti Surge System Gas Pipe of Multistage Centrifugal Recycle Gas Compressor with Process Heat Exchanger in Power Former Unit in Daura Refinery

Ідентифікатор передпомпажних станів компресора авіаційного ГТД

Surging is a dangerous operating mode of the compressor; in this mode, destabilization and flow stall occur, causing intense pressure fluctuations of the working fluid in the flow path or gas-dynamic shocks. Surging phenomena in gas turbine engines lead to a loss of thrust, are accompanied by an increase in the temperature of gases in front of the turbine and an increase in the level of vibration because of large amplitudes of pressure pulsations and mass flow rates along the engine path. The possibility of occurrence of these phenomena is a serious obstacle to increasing the reliability of gas turbine engines, including flight safety in general. The study of non-stationary processes in compressors shows that surge is preceded by such phenomena as pre-surge and rotating stall, which are called the pre-surge state of an aircraft GTE compressor. The study aims to develop informative criteria for the timely detection of the pre-surge state of the compressor of an aircraft gas turbine engine and to build an anti-surge algorithm for the functioning of the proposed identifier based on the developed criteria. To assess the stability of pressure pulsation periodicities, it is proposed to process and compare the signals received from fast-response sensors located in the compressor. In this article, informative criteria are formed for identifying the pre-surge state of an aircraft GTE compressor. The first criterion is the level of stability of the periodic component of pressure fluctuations. The second criterion is the limit of the relative range of pressure pulsations in the compressor. With the help of the obtained criteria, the pre-surge area is divided into pre-surge, weak stall, and intense stall. Such detailing makes it possible to prevent erroneous wear (in high-cost modes) and premature wear (in case of non-intensive disruption) of the anti-surge control system. Based on the criteria obtained, an algorithm for anti-surge adjustment was developed, according to which the anti-surge system is prepared for testing when a pre-surge or weak stall occurs in the compressor flow path, and is triggered when an intense stall occurs. Based on the anti-surge algorithm, a scheme for identifying the pre-surge states of an aircraft GTE compressor is proposed in the form of a three-level alarm and protection system. Recommendations for the practical implementation of the identifier are described.

Data Analysis for the Aero Derivative Engines Bleed System Failure Identification and Prediction

Middle size gas/diesel aero-derivative power generation engines are widely used on various industrial plants in the oil and gas industry. Bleed of Valve (BOV) system failure is one of the failure mechanisms of these engines. The BOV is part of the critical anti-surge system and this kind of failure is almost impossible to identify while the engine is in operation. If the engine operates with BOV system impaired, this leads to the high maintenance cost during overhaul, increased emission rate, fuel consumption and loss in the efficiency. This paper proposes the use of readily available sensor data in a Supervisory Control and Data Acquisition (SCADA) system in combination with a machine learning algorithm for early identification of BOV system failure. Different machine learning algorithms and dimensionality reduction techniques are evaluated on real world engine data. The experimental results show that Bleed of Valve systems failures could be effectively predicted from readily available sensor data.

Application of Centrifugal Compressor Control and Anti-surge System Control

Application of Centrifugal Compressor Control and Anti-surge System Control

The Application of PLC in Anti-surge System of Centrifugal Compressor is Discussed

The Application of PLC in Anti-surge System of Centrifugal Compressor is Discussed

Experimental Analysis of Surge-Detection System Based on Pressure Derivatives at Part-Speed Operation

Abstract This paper presents tests of an antisurge system based on pressure derivatives. The control algorithm was proven to work on different machines and with different unstable flow phenomena. Compressors are known to be affected by unstable flow conditions appearing at low mass flowrate conditions. The best known and most dangerous phenomenon is surge, which is a global instability affecting the entire impeller and regions upstream and downstream from it. A list of identified local phenomena includes among others: impeller rotating stall, diffuser rotating stall, and inlet recirculation. All have a specific pressure signature that is used for early identification. The method presented in this paper is based on a control parameter named the rate of derivative fluctuation (RDF). This approach involves a simple measure of flow instability that is universal and reacts to flow disturbances. RDF has been already confirmed to identify inlet recirculation and surge. The aim of this study is to conduct real-time tests of an antisurge system, implementing the RDF algorithm triggering the safety valve opening. The study confirmed the optimal position of the monitoring point. The results showed that the RDF is indeed sensitive to different types of flow instabilities appearing in different impellers, and that it provides efficient flow stability monitoring.

Modeling and analysis of the compressor for the closed cycle system on anti-surge process

In order to study the interaction mechanism of the pipe network, the compressor and the control system in the process of the anti-surge regulation, the simulation model of the overall Closed Cycle System (CCS) is established in this paper. By comparing the simulation results with the target values at the Design Operation and the Maximum Mach Operation, the calculation deviation is less than 1%, which verifies the accuracy of the model. At the Maximum Mach Operation, the analysis of the CCS during the quasi steady process and the dynamic process is carried out respectively. According to the result of quasi steady state analysis, the effectiveness of the designed anti-surge circuit during the normal operating process of the CCS is verified. By opening the Anti-Surge Valve, additional 38.5% surge margin is provided. And the surge margin at the simulation process would be slightly higher than the design value for the variation of the inlet condition from the different operations. Through the dynamic analysis, the changes of the different performance parameters are studied in the process of sudden blockage in the pipe network, and during this process the compressor surge could be induced easily due to the sharp decline of the inlet pressure. To ensure the safety of the compressor during the acceleration and deceleration process, the moving trajectory of the operation point on the Compressor Characteristic Map should be studied by considering the effect of the resistance characteristics of the CCS pipe network. In addition, the anti-surge system should have a high response frequency to deal with the sudden blockage.

ACOUSTIC METHOD AND HARDWARE-SOFTWARE COMPLEX OF OPERATIONAL DIAGNOSTICS PRE-STAGE STATE OF GAS TURBINES ENGINES BASED ON INVARIANTS RANDOM PROCESS

One of the reasons for the early decommissioning of gas turbine engines (before the specified resources and service life are depleted) is the occurrence of unstable operating modes, namely surge. Surge is a violation of the stable operation of gas turbine engines, due to the occurrence of longitudinal self-oscillations of the flow in the entire airgas path of the gas turbine engine, resulting from the loss of dynamic stability of the flow, accompanied by a sharp drop in thrust and powerful vibration that can destroy the engine. An acoustic method for diagnosing the presurge state of gas turbine engines has been developed, based on an assessment of the change in the distribution of the amplitudes of a vibroacoustic signal, which is characterized by the use of an invariant characterizing the normal distribution of random variables, which makes it possible to quickly assess the presurge state regardless of the type, size and history of engine operation, which makes this method universal. The use of the developed acoustic method for determining the presurge state of gas turbine engines makes it possible to avoid the need for noise filtering, which at the present stage of development of presurge condition diagnostics systems based on vibration analysis plays a huge role. To implement the developed acoustic method, a hardware-software complex was created. The antisurge system can be used in automatic mode by installing hazardous and critically dangerous zones in the program for informative parameters and invariants characterizing the occurrence of surge.

Numerical Model of a Deep Surge Cycle in Low-Speed Centrifugal Compressor

Abstract In this article, a numerical model of the full surge cycle is presented for the low-speed centrifugal blower and compared with the experiment. Surge phenomenon is very dangerous for the compressor operation. Therefore, the possibility of studying its physics experimentally is strongly limited. The application of numerical methods allows one to safely analyze surge physics without causing risks to the operating crew. This article presents a description of the applied numerical method and exhaustive analysis of the flow structures observed at consecutive stages of the surge cycle. The surge is known to be very difficult to be simulated due to large timescale and region of influence. This study also shows the importance of an appropriate choice of the simulation definition and the boundary conditions. The presented method allows gathering information about features such as the regions of flow reversal, pressure distributions, pressure rise, cycle frequency, and others. All the aforementioned information provides important input to the efficient antisurge system design. The model has been validated by a comparison with the experimental data. Thanks to simulation, standardized antisurge solutions could be possibly replaced with more efficient protection schemes tailored to a given machine.

Improving the reliability of the compressor unit using the wavelet transform method

Centrifugal compressors are an integral part of modern production in such industries as gas transmission, oil refining, metallurgical, machine-building, mining, as well as in electric and heat power engineering. Interruptions in the operation or failures of compressors lead to decrease in profit or large material loss. Conditions should be created for the safe (stable) operation of centrifugal compressors. Surge is global (complete) loss of stability, an unacceptable phenomenon for a centrifugal compressor. Compressor surge protection must function during operation. The algorithms used to protect centrifugal compressors against surge have some drawbacks, which makes it impossible to reliably prevent surges. There are many methods for analyzing rapidly changing processes in the flow part of a centrifugal compressor. The wavelet theory is the most accurate and modern method. The use of the wavelet transform method for signal processing allows us to solve the problems of analyzing non-stationary processes of a centrifugal compressor to expand the acceptable range of work and build reliable operation of the anti-surge diagnostic system. In the future, it is possible to use other basic wavelet functions, for comparison and selection of the most suitable one, for the analysis of unsteady signals in a centrifugal compressor.

Numerical analysis of centrifugal compressor operating in near-surge conditions

In order to reproduce the near-surge operation of centrifugal compressor a series of numerical simulations in ANSYS CFX have been conducted. Different settings of boundary conditions have been investigated in purpose of providing a combination allowing to model surge without non-physical flow constraints. This, in turn, would be a step towards modelling of antisurge system. As the conclusions, it was observed that there is no possibility of simulating near-surge working regime without mass flow rate definition as a boundary condition. However, it is achievable to determine a throttle characteristic, which can be used as a function defining the outlet pressure and indirectly the mass flow rate. In case of transient simulations, it would allow to analyse both steady and unsteady regimes of the flow in a centrifugal compressor.

Surge protection system development in centrifugal compressor with an indicative method using numerical simulation of unsteady processes and analysis of pressure fluctuation signals

Nowadays, anti-surge protection system based on parametric method is widely used. The disadvantage of this anti-surge system is the fact that it is not possible to fully ensure the safe operation of the compressor at low flow conditions, because large measurement error will occur. Other method of anti-surge protection is indicative method. This method is what it is necessary to detect occurrence of rotating stall in time on the score of information criterion. Further the control decision is accepted in connection with the approach to the danger zone of surge. Indicative method is more complicated and requires special signal analysis such as wavelet analysis, correlation analysis. Also in addition to the methods of analysis, important is the length of the sample for processing unsteady pressure fluctuations and the method of its displacement on time. It is now possible to mathematically pre-simulate unsteady processes in the flow part of centrifugal compressor.

Thermo-environmental and economic analyses of an integrated heat recovery steam-injected gas turbine

Abstract One of the methods of gas turbine performance improvement is steam injection into combustion chamber. Moreover, heat recovery is introduced as another method for enhancing energy and exergy efficiencies. In this paper, these two methods were combined in a system of Integrated Heat Recovery Steam Injected Gas Turbine (IHRSI) equipped with an anti-surge system. A heat exchanger was used for waste heat recovery of the gas turbine exhaust and steam production. In these conditions, due to the energy balance in the HRSG, there was a relation between steam temperature and steam mass flow rate. One problem in IHRSI is determining optimum steam temperature. The increment of temperature decreases the steam mass flow rate and consequently has opposite effects on the various parameters. Therefore, in the present study, a comprehensive model based on the energy, exergy, environmental and economic analyses (4E) was presented. Eventually, the developed model introduced the optimum conditions of injected steam into combustion chamber. The optimum steam temperature of 318.5 °C was found in the case of 38 °C ambient temperature and 10% relative humidity. IHRSI at the optimum steam temperature increased net power output and thermal efficiency by 56 MW and 4.6% and reduced the cost of power generation by 25.5%.

Measurement and Prediction of Centrifugal Compressor Axial Forces During Surge—Part II: Dynamic Surge Model

The force acting on centrifugal compressors is an important parameter to be considered throughout the operating life of these turbomachines. When the compressor is operating in surge conditions, these forces can become highly dangerous for the mechanical and aerodynamic structures. This instability is usually avoided in industrial applications, but the antisurge system may not react in time when emergency shutdowns or power failures take place. During these rapid transients, surge can develop, generating unsteady forces which can harm the close clearance components of the compressor. Therefore, the capability to predict the characteristics and the dynamics of these surge forces would allow the estimation of the off-design fatigue cycles produced on these components by surge. Currently, no validated method exists to predict the frequency and amplitude of the surge forces and determine the potential damage of these components. In this paper, a lumped parameter model, developed by using the bond graph approach to predict the dynamic surge fluid-dynamic oscillations, is presented. The model requires the geometry and the steady-state performance maps of the compressor as inputs, together with the piping system configuration characteristics. The simulator is provided with a supplementary tool to estimate the axial force frequency and amplitude, taking into consideration all the contributions to the axial fluid-dynamic thrust, the stiffness-damping of the thrust bearing, and the mass of the rotor. The model was tuned and validated using the test case axial force data from the Southwest Research Institute (SWRI) facility. The model has shown good agreement with the experimental results which implies that it can offer significant information about the severity of a surge event and the quantification of the machine performance losses together with possible damage to the close clearance components. This study is a first important step that can lead to schedule optimization for maintenance and repair activities.

A short-cut graphical method for sizing of recycle valves in anti-Surge system considering time delay

A surge in a centrifugal compressor can cause critical damage to the compressor, resulting in large repair costs, so one of the most important considerations in the design of compressor systems is to prevent a surge. However, conventional methods to size recycle valves in anti-surge systems are limited in that the valve characteristics and time delay cannot be quantitatively considered. This paper suggested a short-cut graphical method to easily size the recycle valves in an anti-surge system by considering the valve characteristics, including the dead time, actuation time, and opening types. Dynamic simulations were carried out to verify the resulting size of the valves, and the results of the simulation showed that a surge could be avoided effectively and economically.

Fast-acting anti-surge system of gas turbine engine

Fast-acting anti-surge system of gas turbine engine

CONTROL SYSTEM SURGE OF CENTRIFUGAL COMPRESSORS

The article investigates the anti-surge protection systems and mathematical modeling of systems of gas compressor units on the basis of centrifugal compressors with anti-surge valve or baypass, and a mixed protection system. The review of existing systems, surge protection of gas compressor units, which revealed a number of shortcomings when using antisurge valve or baypass system. The proposed mixed system of surge protection with simultaneous use of surge valve and baypass system. The proposed sequence of the mixed system of surge protection. The above block diagram of an electromechanical system centrifugal compressor – anti-surge valve - direct current motor with an automatic control system. Obtained by use of transient surge valve baypass and mixed anti-surge system. These conclusions underline the relevance of the research and energy efficiency centrifugal compressor anti-surge protection system.

Certain features of GTE combustion chamber open-type nozzles

In this paper, we consider the capability of GTE centrifugal open-type nozzles to recover combustion in the main combustion chamber at short-term fuel cutoffs into the fuel manifolds, when the anti-surge system operates, as well at actuation of “emergency brake” or the “dipping and shutdown valve”. We describe some features of the centrifugal open-type nozzles that make it possible to ensure the stable operation of the combustion chamber even at the “lean” blow-off boundary at α CC max ≤ 65. The possibility of combustion recovery without using the spark plugs after the anti-surge system actuation has been experimentally confirmed.

Latest techniques and practical notes on anti-surge systems for centrifugal compressors

The operating range of process centrifugal compressors is limited by an instability range commonly called “surge”, which occurs during low flow or high head conditions and can result in extensive damage. There are high expectations to improve anti-surge systems of process compressors to increase reliability as well as energy efficiencies and performance. Practical recommendations on anti-surge system sizing, selection, configuration and design are presented. Considerations regarding stall, choke, dynamic studies, anti-surge loop configuration, recycle cooling, anti-surge valve, instruments and anti-surge system parameters are also discussed. Case studies are presented.