The antisurge controller manipulates antisurge valve to give actions in the recycle lines when a surge. It requires details information on air compressor operating conditions which oem can supply compressor performance curve to calculate surge line and how conservative one would like to adopt on control line. Compressors represent some of the most valuable pieces of equipment within an lng facility and it is the job of the antisurge valve to protect them. Surging can cause the compressor to overheat to the point at which the maximum allowable temperature of the unit is exceeded. 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. In order to develop compressor network control strategies, it is necessary first to express compressor performance in an invariant. Compressor performance control the ultimate goal of compressor performance control is to match the compressor delivery to the process demand. Pic uic ft pt tt pt tt antisurge valve suction valve capacity control compressor cooler. However, control strategies have not previously been studied thoroughly from a control theoretic viewpoint. Critical features of surge control systems are explained, and options for different arrangements are given. 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.
The antisurge controller manipulates antisurge valve to give actions in the recycle lines when a. Antisurge systems are therefore employed to be activated to prevent the unit for undergoing surge. 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. Energy control technologies ect is controlling hundreds of machines with millions of hours of operation all over the world. Centrifugal compressor surge, modeling and identification. The system will also provide smooth control at the surge control line, while also having the additional capacity to step the valve open to prevent compressor surge due to rapid drops in flow caused by upsets in the process. Typically the pi proportional integral control algorithm will active and start to modulate the anti surge control valve if the compressor operates between the control line and the surge line.
Compressors represent some of the most valuable pieces of equipment within an lng facility and it is the job of the anti surge valve to protect them. 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 instability is characterized by large limit cycle oscillations in compressor. The surge control algorithm executes in less than 25 ms. Anti surge valve requirements depend to a large degree on the compressor type, the compression system arrangement, and particularly the volume of the discharge piping downstream of the compressor. Model predictive control mpc is a common choice in the industry to solve such multivariable and constrained control problems. Sep 25, 2017 the chief protecting agent of a centrifugal compressor is the anti surge linevalve that recycles cold gas from the discharge side cooler back to the suction scrubber to keep the operating point.
Antisurge systems for axial compressors turbomachinery. The model is designed for anti surge control validation, and models a continuous flow gas compressor. Surge is a characteristic behaviour of a centrifugal compressor that can occur when inlet flow is reduced such that the head developed by the compressor is insufficient to overcome the pressure at the discharge of the compressor. Understanding centrifugal compressor surge and control. Antisurge control ccc compressor controls corporation. These anti surge systems or surge control systems consist of one or two recycle lines around the compressor, which are equipped with fast acting valves that open when the compressor approaches the surge limit. Anti surge control of centrifugal compressor at pt.
The paper emphasizes the interrelation between the process system and the compressor. Dot lined cooler dwg is requested by anti surge system and solid line coolers is requested by compressorprocess itself. Dot lined cooler dwg is requested by anti surge system and solid line coolers is requested by compressor process itself. By moving the compressor s operating point closer to the surge limit line, you can operate more efficiently. This article explains surge phenomena and discusses why the antisurge protection system is a very important part of a compressor surge. Centrifugal and axial compressors are susceptible to surge which can cause catastrophic damage to your turbomachinery train. Compressor antisurge control for a gas turbine engine filed feb. Normally, a polynomial equation is used to approach the control line. Xmbv, with qtrim metso automation piston actuator full bore, metal or soft seated ball valve ansi 150 or 300, din pn 1040 flanged construction carbon steel or stainless steel body stainless steel trim, with pressure reducing qtrim. Pdf surge control and dynamic behavior for centrifugal gas. Compressor loadsharing control and surge detection. Using active control a control system feeds back perturbations into the. Applications this surge control strategy is applicable to both variable speed and constant speed compressors. Evaluation of antisurge control concepts during esd.
It is also applicable to axial and centrifugal compressors. Tasc is implemented on an embedded system for the control of compressor stations with electrical variablespeed drives vsd which are used in applications such as natural gas transportation via pipelines. A new approach to designing centrifugal compressor surge. Apr 29, 2015 this is the first of a threepart series by the author. The following simplified functional block diagram illustrates the features of the algorithm. Anti surge valves for dynamic compressors chemical. Apr 14, 2017 surge is a characteristic behaviour of a centrifugal compressor that can occur when inlet flow is reduced such that the head developed by the compressor is insufficient to overcome the pressure at the discharge of the compressor. Compressor antisurge control for a gas turbine engine q filed feb. Anti surge protection is provided by a control valve which will either exhaust the gas or vapor from the compressor into the atmosphere, or recirculate it back to the compressor inlet. Anti surge systems are therefore employed to be activated to prevent the unit for undergoing surge. Antisurge control provides regulation of compressor parameters to maintain minimum flow through the compressor to avoid stall and surge. Moreover, a cooler in the recycle line may have to be considered, to suitably control the suction temperature and thereby prevent the compressor from going into. When the plenum pressure behind the compressor is higher than the compressor outlet pressure, the fluid tends.
The goal of any compressor controller is to operate turbomachinery within a safe operating envelope. This involved ramping open the anti surge valves at the initiation of a process shutdown. Section 3 description of surge 31 surge versus stall surge is a dynamic instability that occurs in dynamic compressors. 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. Compressor anti surge control for a gas turbine engine filed feb. Aside from surge limits, compressor controllers must be designed to handle a number of physical limitations including. Pdf gas compression package gcp is a vital system in the distribution of gas. Pdf modelling of variable speed centrifugal compressors. Matching antisurge control valve performance with integrated.
This prevents surge on a compressor trip and also holds the valve in a fully open position for startup. Pdf model predictive anti surge control of centrifugal. Anti surge control system for centrifugal compressors part 2. Pertamina ep, in this regard as a stateowned company. The system outlet has a check valve to prevent reversed. The application of control valves to compressor anti surge systems control valves in turbo compressor anti surge systems 03 the problem of compressor surge pipelines transporting gases and vapours are invariably dependent on centrifugal or turbocompressors for the propulsion of these fluids.
When flow element installed at discharge line, discharge flow shall be converted to suction flow by installing pressure transmitter at both lines. Anti surge control valve gas compressor free 30day. This is the first of a threepart series by the author. Measuring errors when the location of the surge line is determined. For this reason the anti surge recycle connection and antisurge control valve shall be located upstream of the check valve as close as practical to the compressor discharge connection. Compressor surge prevention control implemented on yokogawa. Antisurge protection system for compressors turbomachinery. In an earlier surge control post, s greg mcmillan noted that surge valves typically have response times from 1 to 5 seconds. Single stage compressor control rockwell automation. Control valves in turbo compressor anti surge systems control valves in turbo compressor anti surge systems kentintrol. Compressor surge is a form of aerodynamic instability in axial compressors or centrifugal compressors.
In this article torque assisted anti surge control tasc, a compressor anti surge control system based on model predictive control mpc is presented. Us3080712a compressor antisurge control for a gas turbine. Anti surge control system for centrifugal compressors. Surge control and dynamic behavior for centrifugal gas. Antisurge control is an important issue in operation of e. Compressor anti surge control for a gas turbine engine q filed feb. If the valve optimising performance joe demonte, emerson, usa, outlines how to select the right antisurge valves to achieve and maintain the highest level of. Important aspects of anti surge valve sizing and selection for plants in the chemical process industries cpi, as well as examples, are discussed in. And the tballs unique combination of high capacity and high turndown offers superior control and protection throughout the compressors speed range. As briefly explained above, to avoid the surge phenomenon, there are an anti surge control system that analyze the compressor operating point and modulate the anti surge control valve as necessary before designing the anti surge control valve, the compressor manufacturer usually has some anti surge system study with some set of process data required to design. The only obstacle for a traditional industrial mpc implementation for anti surge control is the stringent realtime requirements of compressor anti surge control, which can have execution cycle times down to 40 ms. 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. Therefore, the control system, as well as the phenomenon of surge and stall is discussed.
Introduction the control of centrifugal compressors has to be considered both from the perspective of the compressor and the perspective of the process. Protect your critical compressors from failure and shutdowns. Selection criteria in compressor antisurge valves some of the most consistently popular posts here on the blog involve compressor anti surge control. Anti surge controller working principle instrumentation tools. Gas compression and drying fractionation and distillation product storage they are used, for example, to compress the cracked gas before the fractionation stage, com. Pdf modelling of variable speed centrifugal compressors for. Ect provides the latest in control solutions designed to maximize your plants production and efficiency. Compressor fouling and changes in gas composition 16. Sep 04, 2017 anti surge control system for centrifugal compressors part 1 trainings hub by dr.
Some works use both the compressor rotational speed and the position of an anti surge valve asv, also called recycle valve, for anti surge control, see e. The chief protecting agent of a centrifugal compressor is the antisurge linevalve that recycles cold gas from the discharge side cooler back to the suction scrubber to keep the operating point. The sds concerns the performance of a compressor system in a gas conditioning plant. Anti surge control system for centrifugal compressors part 1 trainings hub by dr. An improperly designed surge control system can lead to multiple surge events increasing the risk to personnel safety and major damage to the compressor. Antisurge valves are provided on both casings of the compressor. Sep 05, 2017 anti surge control system for centrifugal compressors part 4. Centrifugal compressor surge, modeling and identification for. Regarding the compressor, it is necessary to discuss the. Antisurge control application as the only way to prevent surge is to recycle or blow off flow to keep the operating point away from the surge limit. A mathematical model for simulation of gas compressor systems is developed. An effective antisurge control system will generally be able to operate with a surge margin of 10% of the surge line flow.
Royal belgian institute of marine engineers surge detection. The required control response is a function of the response time of the surge valve, measurement devices and control algorithm relative to the surge dynamics of the compressor. The application of control valves to compressor antisurge systems control valves in turbocompressor antisurge systems 03 the problem of compressor surge pipelines transporting gases and vapours are invariably dependent on centrifugal or turbocompressors for the propulsion of these fluids. Compressor loadsharing control and surge detection techniques. To configure an anti surge controller is not a straight forward task like configuring controls hardware. There are many station events that can cause a centrifugal compressor to surge, such as interaction with other units, reciprocating compressor pulsations, and upset conditions like sudden. Anti surge controller working principle instrumentation. Compressor loadsharing control and surge detection techniques wayne jacobson. It is a phenomena accompanied by centrifugal compressors having continuous flow rate, gas path inside compressor flows having an acceptable value of eddies. They are used to control the pressure of the compressor. Surge control considerations in centrifugal compressors. This involved ramping open the antisurge valves at the initiation of a process shutdown. Industrial compressor antisurge computer control citeseerx. This is achieved by varying the compressor throughput, which is why the term performance control may be also be called capacity control.
Understanding centrifugal compressor surge and control what. Mimic compressor with surge object computes dynamic compressor response including hidden flow characteristics during surge. The system outlet has a check valve to prevent reversed flows. Pdf industrial compressor antisurge computer control. Antisurge protection is provided by a control valve which will either exhaust the gas or vapor from the compressor into the atmosphere, or recirculate it back to the compressor inlet. Surge is defined as the operating point at which centrifugal compressor peak head capability and minimum flow limits are reached. Abstractthe paper presents a compressor antisurge control system, that results in maximizing compressor throughput with pressure standard deviation.
This is defined as the surge cycle of the compressor. The knowledge gained from the model was critical to show the extreme jumps in flow caused by positive feedback on the hidden characteristic curve to the left of the surge point. Pdf surge control and dynamic behavior for centrifugal. The ccc antisurge controller accurately models the surge limit line for all operating conditions of the compressor. Protecting a centrifugal compressor from surge pipeline. This article explains surge phenomena and discusses why the anti surge protection system is a very important part of a compressor. Requirements for antisurge control api asks for 10% safety distance between surge line and control line. 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. As briefly explained above, to avoid the surge phenomenon, there are an anti surge control system that analyze the compressor operating point and modulate the anti surge control valve as necessary before designing the anti surge control valve, the compressor manufacturer usually has some anti surge system study with some set of process. Also, surging can cause damage to the thrust bearing due to the rotor shifting back and forth from the active to the inactive side.
Anti surge control free download as powerpoint presentation. Surge cycles occur keywordsantisurge, control, compressor, pid control, safety, fast and can even go undetected if the applied instrumentation fault tolerance. 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 mechanical damage. These antisurge systems or surge control systems consist of one or two recycle lines around the compressor, which are equipped with fast acting valves that open when the compressor approaches the surge limit. Evaluation of antisurge control concepts during esd 2. Centrifugal compressor surgebasics, mechanism mechanical.
A reliable control valve that functions consistently under the most severe conditions is absolutely essential to the protection of the compressor. Procidia control solutions compressor surge control. If the valve optimising performance joe demonte, emerson, usa, outlines how to select the right anti surge valves to achieve and maintain the highest level of. The set point of the pi controller is a flow rate that lies on the control line. Constant speed lines sens or pa rumeter a t compressor pressure ratio fig.
In modern compressor control theory, a surge control line scl is developed to protect the compressor, so. These antisurge systems or surge control systems consist of one or two recycle lines around the compressor, which are equipped with fast acting valves that. 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 compressor s operating point and its surge limit line. Turbocompressor antisurge control, new solution for an old problem. A feed forward control strategy, therefore, was recommended to improve transient behavior. Nov 27, 2015 adding more safety margin to the surge control line would significantly affect compressor operational flexibility. The becker tball antisurge valve is a complete antisurge control solution that delivers high performance and reliable protection even in the most demanding operating environments. This report on compressor antisurge control closes some of the gaps related to the signi. Anti surge control system for centrifugal compressors part 5 duration. Surge control design for centrifugal compressor systems. Evaluation of anti surge control concepts during esd 2. Its a condition in centrifugal and axial compressors where a flow reversal condition can occur. Secondary pid loop overrides, and capacity control are not shown for clarity.
May 12, 2016 loop control fine points of compressor surge control compressor damage and costly production outages can be prevented by attention to surge curves, control strategies and valve response. Ect engineers high value control solutions for turbomachinery, positive displacement compressors, and. The reasons are multitude ranging from a driver failure, power failure, upset process conditions, startup, shutdown, failure of anti surge mechanisms, check. Our controller combines both closed and open loop control responses to prevent surge without requiring a large control margin while minimizing recycling and unnecessary upsets to the process. Pdf anti surge control of centrifugal compressor at pt. Fine points of compressor surge control control global. An effective anti surge control system will generally be able to operate with a surge margin of 10% of the surge line flow. The anti surge controller manipulates anti surge valve to give actions in the recycle lines when a surge. Adding more safety margin to the surge control line would significantly affect compressor operational flexibility. Compression antisurge 27220301 en application report 811 3 features of the valve valve type.
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