However during the performance test with a partial load, a small subsynchronous vibration 0. This means that subsonic and transonic operation conditions are analysed. Subsynchronous vibration can be either destructive or harmless depending on the root cause. Phenomena observed a subsynchronous vibration appeared at 11,100 rpm in a full load operation. Numerical simulation and its experimental validation. Centrifugal compressors vibration, dynamics and noise. Synchronous vibration an overview sciencedirect topics. Centrifugal compressors respond to changes in plant demand by two means. Case study on the subsynchronous vibration by external forces in integrally geared centrifugal compressor seunghoon shin hanwha power systems sh23. This paper summarizes the independent investigation conducted to evaluate the compressors rotordynamic. Causes of subsynchronous vibration in integrally geared compressors evan b. Introduction vibration types two types of potentially problematic vibration in industrial compressors are synchronous vibration and subsynchronous vibration.
Investigation of a rotordynamic instability in a high. Download a pdf of this article figure 1 this drawing shows typical vibration monitoring locations for a reciprocating compressor. Influence of centrifugal compressor system components on its. This article will introduce the basics of using vibration data to determine the mechanical condition of pumps and implement it in a predictivepreventive mainte.
Six techniques for solving vibration problems with forced excitation. Root cause investigation of subsynchronous vibration in a. Api centrifugal compressor oil seals and support systems types, selection, and field troubleshooting. Flow modulation is nearly always present in centrifugal and axial compressors and can cause aerodynamic excitation which is one of the main sources of subsynchronous vibration ref. Investigation on the subsynchronous vibration fault. The example centrifugal compressor considered in this paper is driven by a steam. Vibrational diagnostics of rotating stall in centrifugal compressors.
Case study on resolving oil whirl issues on gas compressor john j. Subsynchronous vibration and compressor rotor instability. They have proven to provide a high level of reliability, efficiency and design flexibility. Two distinct subsynchronous vibrations were encountered in commissioning an eight stage centrifugal compressor. Misdiagnosing the root cause can lead to destructive failure or unnecessary design changes. Pdf synchronous and sub synchronous vibration under the. Axial and centrifugal compressors application guide. Pdf machinery vibration and rotordynamics semantic scholar. Rotating stall usually results in an appearance of a low subsynchronous frequency component in the rotor vibration spectrum frequency ratios are typically. Subsynchronous vibration on centrifugal compressor. Some field experience with subsynchronous vibration of centrifugal compressors wang xixuan, gu jinchu, zhejiang university, hangzhou shen qingen, hua yongli, zhu lansheng du yuntian zhengzhou polytechnic institute, henan peoples republic of china a lot of large chemical fertilizer plants producing ton nh3day and. This valve is controlled by a signal from a control panel mounted near the compressor. By harmonizing these technical requirements into a single set of. Two vibration types of concern in industrial compressors are synchronous and subsynchronous vibration.
Heavily participate in organization capability development. This case study reports a selfexcited vibration of a multistage backtoback centrifugal compressor rated speed 11,520 rpm supported in tilting pad journal bearings. Williams product engineer fselliott export, pa, united states john r. Synchronous and sub synchronous vibration under the combined effect of bearings and seals. Power for land, sea and air, june 812, 2009 in orlando, florida. The nature of this ssv was deeply investigated and finally it was fixed through a balance piston seal geometry change. A serius candidate to be responsable of a subsynchronous vibration in a ce ntrifugal pump is the whirl. Centrifugal compressor systems can generate flow induced or acoustic induced vibration, and can experience surge problems.
Stability analysis and testing of a train of centrifugal. Conclusions in order to prevent subsynchronous vibrations in rotating machines, highdensity gas centrifugal compressors included, the latest editions of the api standards have established new design requirements, which include theoretical models for stability analysis. I am not an ezpert in this particula subject but i can recomend some literature. Definition of a screening criterion for centrifugal. While testing at a speed of 21,500 rpm and a discharge pressure of 2,300 psi using nitrogen as the testing medium, the compressor. An investigation was conducted on the suppression of subsynchronous vibrations due to aerodynamic response to surge in a twostage centrifugal compressor with air foil bearings. He supervises the calculation activities related to centrifugal compressor design and testing, and has specialized in the areas of rotordynamic design and vibration data analysis. Torsional vibration on compressors and pumps duration. The vibration amplitude was larger than that of synchronous component. Badini principal engineer, pe fselliott export, pa, united states evan b. Balancing piston for centrifugal compressors, to control and damp subsynchronous vibrations, comprising a cylindrical body which is secured onto the rotor and a cylindrical structure which contains the body on the stator side with interposition of a seal with small cells wherein the play between the rotor and the stator increased in the direction of the flow of gas through the play.
Integrally geared centrifugal compressors igcs are a wellestablished and continually growing segment of the turbomachinery industry. Instability characterized by subsynchronous vibration near the first whirling frequency that rapidly grows to a large amplitude bounded only by. Oil seal effects and subsynchronous vibrations in highspeed compressors paul e. Understand your process, as well as the advantages and disadvantages of each centrifugal compressor configuration, in order to choose the optimal centrifugal compressor for your application. The two cases study of this researchwere selected of f our identical centrifugal compressors have been commissioned in may 2010and since then there were many identical high vibration amplitude issues which consequences the compressor tripped, this issues were investigated numerically and experimentally in this thesis.
Ep1270950a2 balancing piston for centrifugal compressors. An inlet guide vane or butterfly valve is located near the inlet to the first stage usually on the compressor casing. Centrifugal compressor stability prediction using a new physics based approach, proceedings of asme turbo expo 2009. Figure 111longitudinal cross section pdo, harweel lp compressor manual. For high pressure centrifugal compressor, aerodyanmics induced vibration.
Centrifugal compressors are widely used to compressor gas in many different processes within the petroleum and chemical industry. The behaviour of the compressor was free of subsynchronous vibration down to 68 %, very much lower than the 74 % found in the similitude tests. Sorokes dresserrand selecting a centrifugal compressor inlet pressure p1 temperature t1. Subsynchronous forced vibrations are often an indication that the compressor is operating near a stage stall condition. Gt driven centrifugal compressor locates at the endusers offshore platform, high level shaft vibration alarm under specific operating conditions was reported from end user. As integrally geared compressor design and applications evolve traditional design limits are tested. Api std 672 packaged, integrally geared centrifugal air compressors for petroleum, chemical, and gas industry services, fifth edition. Williams has been a product design engineer at fselliott company for the last five years in the new product development group. Journal international journal of modern engineering research. Causes of subsynchronous vibration in integrally geared. Us6779970b2 balancing piston for centrifugal compressors. According to the site evaluation test with dynamic measurements, subsynchronous vibration ssv was observed under higher load.
Axial and centrifugal compressors application guide ge oil gas application guide bently nevada asset condition monitoring. Evaluating and correcting subsynchronous vibration in. A balancing piston for centrifugal compressors, to control and damp subsynchronous vibrations, comprises a cylindrical body 21 which is keyed onto the rotor 3 and a cylindrical structure which contains the body 21 on the stator side with interposition of a seal 16 with small cells wherein the play between the rotor3 and the stator 2 increases in the direction of the flow of gas. The centrifugal compressor was equipped with only four out of 10 stages and had undergone development testing a number of years prior. Evaluating and correcting subsynchronous vibration in vertical pumps by malcolm e. Pdf there are several sources of nonsynchronous forced vibration of centrifugal compressor. When a compressor rotor experiences subsynchronous vibration, the problem is generally considered to be a shaft instability problem associated with the. At a running speed of approximately 9000 rpm, a subsynchron ous vibration at 4200 rpm of nearly two times the synchronous vibration level was encountered. Rotating stall usually results in an appearance of a low subsynchronous frequency component in the rotor vibration spectrum frequency ratios fall typically. The 25mb45i compressor successfully passed its mechanical test at the manufacturers facility. Two types of subsynchronous vibrations have been observed.
Alford and the destabilizing forces that lead to whirl and whiporbit, september 1998 the death of. The cause and effects of a large subsynchronous vibration 3. Module 1 reciprocating compressor an overview of vibration issues. Two transient measurements of a compressor setup with an enlarged tip clearance of 2. In both cases, nonsynchronous vibration occurred and limited the compressor operation. Siemensdresser rand centrifugal compressor, nouvo pignone centrifugal and axial compressor, instrument air oil free screw and intergral gear centrifugal compressor, api 610 pumps and cryogenic submersible centrifugal pump. Experience also recommends a minimum of one set of seismic vibration sensors to be mounted on the bearing case to monitor the overall housing vibration. Although the applications and technology of igcs have continued to grow and advance, there are few publications that address subsynchronous vibration ssv. Lucas lyondellbassell abstract new vertical pumps were installed in liquid sulfur service. Mathematical modeling has been performed allowing the development of computer programs that predict the threshold of instability and often allow the designer to. Stability analysis and testing of a train of centrifugal compressors for high pressure gas injection.