Instead of waiting for the compressor to surge, and then reacting, the system calculates when surge is about to occur and takes action to avoid a surge event before it occurs. The difference advanced control technique of centrifugal compressor for complex gas compression processes 27. The developed surge model could better control the considered system. Critical features of surge control systems are explained, and options for different arrangements are given. Mechanical engineer williams gas pipeline houston, tx, usa dr.
We will first discuss the actual implementation of the surge controller on the centrifugal compressor test rig and the experimental results that we have obtained. Now we will various curves and point so check in the centrifugal compressor performance curve. The surge usually starts in one stage of a multistage compressor and can occur very rapidly. The compression system consists of a centr ifugal compressor driven by an electrical motor. How to read a centrifugal compressor performance curve. Antisurge control is completed with control valve to by pass discharge gas back to suction or vented to atmosphere.
A controller is provided for operating a blowoff valve to bring the actual differential pressure to the calculated differential pressure. The red colourmark represents the operating point of the. Actually, the working principle of a centrifugal compressor is increasing the kinetic energy of the fluid with a rotating impeller. Pdf modelling of variable speed centrifugal compressors for. Hrts and operating range surge to choke margin a positive continuous head rise to the compressor surge point at constant speed is crucial to stable compressor operation and reliable responsive process control. It is shown thatby usingthe rotationalspeed of themotoras control, previous unstable operating points to the left of the surge line can be made globally exponentially stable. Download centrifugal compressor surge control systems fundamentals.
Read online centrifugal compressor surge control systems fundamentals. Many facilities employ two or more centrifugal compressors, operated in either series or parallel configurations. Centrifugal compressor surge, modeling and identification. Aug 21, 2018 in this video i have explained surging and choking in centrifugal compressor with pressure ratio verses mass flow rate diagram. The surge is starting with the instant flow reverses, shown in the. Procidia control solutions compressor surge control. Active surge control of centrifugal compressors using. Surge in centrifugal compressor is flow stable oscillation with a largeamplitude. Research fellow nova chemicals calgary, ab, canada jordan grose, p. Surge detection and surge control systems for centrifugal compressors part 2. Us7775759b2 centrifugal compressor with surge control, and. Pdf previous work on stabilization of compressor surge is extended to include control of the angular velocity of the compressor. Typical antisurge control for centrifugal compressor ix.
This article explains surge phenomena and discusses why the antisurge protection system is a very important part of a compressor surge. Meaning of surge in a centrifugal compressor ask a chemical or mechanical engineer, what does a compressor surge do, and he would shudder merely thinking of the consequences. Dave moss, in compression machinery for oil and gas, 2019. The control, or guidance, of this swirling flow is one of the primary purposes of a centrifugal compressors stationary components. A surge control system is disclosed for centrifugal compressors which utilizes an algorithm to calculate a desired orifice differential pressure and compare the calculated result with an actual differential pressure. Axial and centrifugal compressors application guide. It is also applicable to axial and centrifugal compressors. Drive torque actuation in active surge control of centrifugal. Surge control design for centrifugal compressor systems. The advantages of incorporating this control into your automation system is an integrated operator interface, advanced measurement diagnostics, alarming, and reporting information on the compressor. The compression is largely influenced by a centrifugal pump. Centrifugal compressor surge and speed control article pdf available in ieee transactions on control systems technology 75.
Centrifugal compressor surge, modeling and identification for control. This prevents surge on a compressor trip and also holds the valve in a fully open position for startup. All books are in clear copy here, and all files are secure so dont worry about it. Antisurge control ccc compressor controls corporation. Surge control in centrifugal compressors aong website. A new approach to designing centrifugal compressor surge. Pdf gas compression package gcp is a vital system in the distribution of gas. Centrifugal compressor with surge control, and associated method us8272832b2 en 20080417. Compressor surge is typically controlled by detecting when the compressor is nearing the surge line on the compressor characteristic curve and modifying the compressor operation to avoid entering into a surge cycle.
Pdf anti surge control of centrifugal compressor at pt. Apr, 2010 the advantages of incorporating this control into your automation system is an integrated operator interface, advanced measurement diagnostics, alarming, and reporting information on the compressor. Apr 29, 2015 this is the first of a threepart series by the author. It is necessary for startup, shutdown, surge protection and flow control turndown capability. The centrifugal compressor is one of the most commonly used means of gas compression. The effect of cooling water temperature on centrifugal performance. In this video i have explained surging and choking in centrifugal compressor with pressure ratio verses mass flow rate diagram. Basically, these schemes consist of a set of detection devices that either anticipate surge or detect it at its inception, and a set of. This is the first of a threepart series by the author. Fundamentals include dynamic centrifugal compressor map, operating envelope, surge cycle. Surge control and dynamic behavior for centrifugal gas. Understanding centrifugal compressor capacity controls.
Surge is an inherent phenomenon in a centrifugal compressor, defined as reversal of fluid flow which can possibly damage the machine. Us4464720a centrifugal compressor surge control system. Robust adaptive control of surge instability in constant. Active surge control of centrifugal compressors using drive. Manager, vibration integrity group beta machinery analysis calgary, ab, canada steven hill, p. Surge it is a phenomena accompanied by centrifugal compressors having continuous flow rate, gas path inside compressor flows having an acceptable value of eddies and vortices but if these eddies and vortices. The model is designed for anti surge control validation, and models a continuous flow gas compressor. A new approach to designing centrifugal compressor surge control systems kamal botros, ph. Feb 18, 2016 compressor surge and prevention chemical engineering. In this paper, a surge control law for variable speed centrifugal compressors is presented and. An accurately designed surge control system that includes multiple compressors with the associated piping systems is a vital element of a facilitys design and ongoing operational integrity. Publishers pdf, also known as version of record includes final page. Surge is defined as the operating point at which centrifugal compressor peak head capability and minimum flow limits are reached.
This article explains surge phenomena and discusses why the anti surge protection system is a very important part of a compressor. A centrifugal compressor driven by an electrical motor is studied, and the drive itself is used for surge control, thus elliminating the need for additional actuators. Based on the above, process control and in particular, surge control systems are discussed. Surge control problems have been around as long as the centrifugal compressor itself. Centrifugal compressor configurations flow exits an impeller in both a radial direction and a tangential direction, and is often described as swirling outward. Protecting a centrifugal compressor from surge pipeline. Avoiding compressor surge when operating multiple centrifugal compressors case study. The model also includes a cooler for gas cooling, a scrubber for liquid draining, and a recycle line with a control valve for antisurge control. There are several different methods to accomplish surge control. The antisurge control system is designed to determine the surge condition in the compressor and to operate the antisurge control valve in an efficient and speedy manner to protect the centrifugal compressor from the surge.
Centrifugal and axial compressors are susceptible to surge which can cause catastrophic damage to your turbomachinery train. Anti surge controller working principle instrumentation tools. The present invention relates, in general, to surge control systems and, in particular, to a new and useful method and apparatus for controlling surge in a centrifugal compressor. Centrifugal compressor surge, modeling and identification for. Developments in centrifugal compressor surge controla. The instability is characterized by large limit cycle oscillations in compressor. Centrifugal compressors are widely used for natural gas transportation by increasing the pressure of the gas. Compressor surge and measurement centrifugal and axial compressors will surge when forward flow through the compressor can no longer be maintained, due to an increase in pressure across the compressor, and a momentary flow reversal occurs. Compressor surge and prevention chemical engineering youtube. Antisurge control is instruments to detect pressure and flow at where compressor will. Basically, these schemes consist of a set of detection devices that either anticipate surge or detect it at its inception, and a set of control devices that act to prevent surge from occurring. Since it decreases performance and even may damage the compressor, surge is highly undesired in compressor operation.
The centrifugal compressor and its control, will be addressed first, and is follo wed by a description of the process behavior under various scenarios. This strategy, conducted by defining a surge control line that is chosen at a distance from the surge line, tries to keep the compressors equilibrium point to the right side of the surge line by recycling or blowing off the gas compressor. How inlet conditions impact centrifugal air compressors. The achievable rise to surge is directly influenced by the required compressor operating range. Pdf surge control and dynamic behavior for centrifugal gas. Pressure and velocity variation in a centrifugal compressor stage boyce 1993 6.
Improving centrifugal compressor performance by optimizing. The system outlet has a check valve to prevent reversed flows. Understanding centrifugal compressor surge and control what. Pertamina ep, in this regard as a stateowned company. A centrifugal compressors flow and pressure are typically controlled by a combination of. Centrifugal compressor surgebasics, mechanism mechanical. Model predictive antisurge control of centrifugal compressors with. It is a phenomena accompanied by centrifugal compressors having continuous flow rate, gas path inside compressor flows having an acceptable value of eddies and vortices but if these eddies and vortices. Now we will see how the surge starts in a compressor. Cagi and its centrifugal compressor section members atlas copco, fs elliott, hanwha power systems, and ingersoll rand have trained engineers to assist and guide users through selecting the right size compressor for their operation. Us7775759b2 centrifugal compressor with surge control.
The fluid is then slowed down in a volume called the plenum, where the kinetic energy is converted into potential energy in form of a. Cagi and our centrifugal customers all share a common interest and goal to maximize the compressor system efficiency and optimize the system energy usage. Centrifugal compressor is a machine in which a particular gas or vapor is compressed by a radial acceleration by an impeller with the help of a surrounding case. This alternate control system can be used instead of the abovementioned system as shown in figure 5. Piping systems around the compressor must be designed to minimize the volume in the compressor. Compressor surge triggered by diffuser stall can be suppressed by. In air compressors, surge control can be accomplished by opening a discharge end bypass valve and venting air to the atmosphere. Once surge occurs, the reversal of flow reduces the. Centrifugal compressor surge and speed control control.
As these operations are transient in nature, all dynamic parameters. Surging and choking in centrifugal compressor in fluid. In willems 2000 active surge control of a centrifugal compressor is simu. Also, depending on the existing speed and the slope of the surge line, increasing the compressor speed may bring it out of surge. Understanding centrifugal compressor surge and control. There are a number of surge control schemes in current use for centrifugal compressors employed in natural gas transmission systems. When a centrifugal compressor surges, there is an actual reversal of gas flow through the compressor impeller. Compressor surge and prevention chemical engineering. The model also includes a cooler for gas cooling, a scrubber for liquid draining, and a recycle line with a control valve for anti surge control. Pdf surge control and dynamic behavior for centrifugal. Anti surge controller working principle instrumentation. Figure 8 shows an example of the compressors load sharing control system by a master controller for the common header pressure. The antisurge controller is one of the most critical turbomachinery control applications that protect a compressor from surge by continuously calculating the distance between the compressors operating point and its surge limit line.
Section 3 description of surge 31 surge versus stall surge is a dynamic instability that occurs in dynamic compressors. Centrifugal compressor with surge control, and associated method us8061974b2 en 20080911. Compressor surge is a form of aerodynamic instability in axial compressors or centrifugal compressors. Dynamicmodelingapproachtosupportlngplantcompressoroperations. Botros is a world authority on surge control design and analysis, and has focused his research activities on transient flow problems in complex systems, including centrifugal compressor surge phenomenon, pressure relief system dynamics, transients of twophase stratified.
The surge in a centrifugal compressor can be simply defined as a situation where a flow reversal from the discharge side back into the compressor casing occurs causing. It can then be arranged multistage for greater proportions of compression. Understanding centrifugal compressor capacity controls cagi. A mathematical model for simulation of gas compressor systems is developed. Applications this surge control strategy is applicable to both variable speed and constant speed compressors. All good stuff to keep your process operating effectively. The term describes violent air flow oscillating in the axial direction of a compressor, which indicates the axial component of fluid velocity varies periodically and may even become negative. Surge control considerations in centrifugal compressors. Surgecontrolconsiderationsincentrifugalcompressors. Antisurge control shall be installed to centrifugal compressor because at low flow, compressor will surge. Pdf modelling of variable speed centrifugal compressors. A centrifugal compressor can be brought out of a surge condition by reducing the head andor increasing flow. As surge can occur during acceleration of the compressor speed, it is of major concern to develop controllers that simultaneously can control both surge and compressor speed.
The anti surge control system is designed to determine the surge condition in the compressor and to operate the anti surge control valve in an efficient and speedy manner to protect the centrifugal compressor from the surge. The compressor is protected from surging by a predictive control method. Surging and choking in centrifugal compressor in fluid power. Antisurge protection system for compressors turbomachinery. Model predictive antisurge control of centrifugal compressors. The active control of surge, also for high speed machines, is a proven e. The model is designed for antisurge control validation, and models a continuous flow gas compressor. Every centrifugal compressor has its own operating characteristic map. This map will show us the surge line limit and the operating limit. The antisurge controller is one of the most critical turbomachinery control applications that protect a compressor from surge by continuously calculating the distance between the compressors operating point and its. Introduction the control of centrifugal compressors has to be considered both from the perspective of the compressor and. Pdf active surge control of centrifugal compressor using. The surge phenomenon in the centrifugal compressor can be understood as a complete breakdown and reversal of the flow through the compressor. Many different approaches have been taken to improve operating range to surge both in head and flow depending on what type of surge mechanism is present in the compressor system.
179 1087 411 1320 1155 286 522 271 522 824 1497 991 100 1491 999 1307 487 661 1267 784 251 770 6 955 870 1074 555 1416 1157 481 567 1408 1465 941 1104 635 1237 792 971 869 955 482 550