Guidelines in Pulsation Studies for Reciprocating Compressors

2002 ◽  
Author(s):  
Brian C. Howes ◽  
Shelley D. Greenfield
Keyword(s):  
High Efficiency ◽  
Pressure Pulsation ◽  
Piping System ◽  
Reciprocating Compressor ◽  
Efficient Operation ◽  
Pressure Drops ◽  
Design Standard ◽  
Overall Design ◽  
Unbalanced Force ◽  
Gas Compression

While new gas compression in pipeline service tends to be dominated by centrifugal machines, reciprocating compressors still have a significant place in the industry. Specific dynamic design is required to ensure reliable and efficient operation of all reciprocating compressor installations. This requirement is particularly significant in pipeline installations, because the compressor is intended to be in service for many years, and because high efficiency is important for economic reasons. It is widely recognized that the design of these types of installations should include a “pulsation study”. A pulsation study involves analysis of the proposed installation to predict pulsation, vibration, and stress levels. Further, a pulsation vibration control scheme is developed as part of the overall design. The objective is to ensure that predicted pulsation and vibration levels meet guidelines while limiting associated pressure drops and horsepower losses to acceptable levels. Various guidelines have been used in these studies, but the most commonly used standards are in API 618. While this standard was not originally intended for pipeline service, in reality it represents the best design standard available for high specification reciprocating compressor installations in any application. Recently, work has been done to upgrade the API 618 design standard. One of the changes in the proposed new 5th edition is the addition of unbalanced force guidelines to the existing pressure pulsation guidelines. Much discussion occurred regarding the need for and the advisability of making the addition. Real examples show designs in which a reduction of pressure pulsation is accompanied by an increase in unbalanced forces, illustrating the need for an unbalanced force guideline. It is also shown that problems can occur due to unbalanced forces in parts of the piping system not currently addressed by the pulsation guidelines in API 618. The paper compares the current 4th Edition versus the draft 5th Edition. Comments are made on the applicability of the various guidelines. While API 618 is the best available design document, the addition of force guidelines will help API 618 do a better job for industry.

Attenuation of Gas Pulsation in a Reciprocating Compressor Piping System by Using a Volume-Choke-Volume Filter

2012 ◽  
Vol 134 (5) ◽  
Author(s):  
Boxiang Liu ◽  
Jianmei Feng ◽  
Zhongzhen Wang ◽  
Xueyuan Peng
Keyword(s):  
Characteristic Frequency ◽  
Pressure Pulsation ◽  
Natural Frequencies ◽  
Three Dimensional ◽  
Piping System ◽  
Reciprocating Compressor ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Response Characteristics ◽  
Low Pass

This paper presents an investigation of the use of a volume-choke-volume low-pass filter to achieve gas pulsation attenuation in a reciprocating compressor piping system, with a focus on its frequency response characteristics and influence on the actual attenuation effects. A three-dimensional acoustic model of the gas pulsation was established for a compressor discharge piping system with and without the volume-choke-volume filter, based on which the gas column natural frequencies of the piping system and the pressure wave profiles were predicted by means of the finite element method. The model was validated by comparing the predicted results with the experimental data. The results showed that the characteristic frequency of the filter was sensitive to both diameter and length of the choke but independent of the parameters of the piping beyond the filter. It is worth noting that the characteristic frequency of the filter constituted one order of the gas column natural frequencies of the piping system with the filter. The pressure pulsation levels in the piping system downstream of the filter could be significantly attenuated especially for the pulsation components at frequencies above the filter’s characteristic frequency. The measured peak-to-peak pressure pulsation at the outlet of the filter was approximately 61.7% lower than that of the surge bottle with the same volume.

The Impact of Reciprocating Compressor Pulsations on the Surge Margin of Centrifugal Compressors

2016 ◽  
Author(s):  
Klaus Brun ◽  
Rainer Kurz ◽  
Sarah Simons
Keyword(s):  
Centrifugal Compressor ◽  
Pressure Pulsation ◽  
Numerical Approach ◽  
Piping System ◽  
Analysis Tool ◽  
Reciprocating Compressor ◽  
Centrifugal Compressors ◽  
Surge Margin ◽  
Periodic Pressure ◽  
The Impact

Pressure pulsations into a centrifugal compressor can move its operating point into surge. This is concerning in pipeline stations where centrifugal compressors operate in series/parallel with reciprocating compressors. Sparks (1983), Kurz et al., (2006), and Brun et al., (2014) provided predictions on the impact of periodic pressure pulsation on the behavior of a centrifugal compressor. This interaction is known as the “Compressor Dynamic Response” (CDR) theory. Although the CDR describes the impact of the nearby piping system on the compressor surge and pulsation amplification, it has limited usefulness as a quantitative analysis tool, due to the lack of prediction tools and test data for comparison. Testing of compressor mixed operation was performed in an air loop to quantify the impact of periodic pressure pulsation from a reciprocating compressor on the surge margin of a centrifugal compressor. This data was utilized to validate predictions from Sparks' CDR theory and Brun's numerical approach. A 50 hp single-stage, double-acting reciprocating compressor provided inlet pulsations into a two-stage 700 hp centrifugal compressor. Tests were performed over a range of pulsation excitation amplitudes, frequencies, and pipe geometry variations to determine the impact of piping impedance and resonance responses. Results provided clear evidence that pulsations can reduce the surge margin of centrifugal compressors and that geometry of the piping system immediately upstream and downstream of a centrifugal compressor will have an impact on the surge margin reduction. Surge margin reductions of <30% were observed for high centrifugal compressor inlet suction pulsation.

Experiences in Developing a Practical Algorithm of Identification and Attenuation of Pressure Pulsation and Piping Vibration in Gas Reciprocating Compressor Plants and Other Systems

2018 ◽  
Author(s):  
Maciej Rydlewicz ◽  
Wojciech Rydlewicz
Keyword(s):  
Pressure Pulsation ◽  
Industrial Applications ◽  
Piping System ◽  
Reciprocating Compressor ◽  
Mechanical Vibrations ◽  
Dynamic Forces ◽  
Piping Systems ◽  
Practical Engineering ◽  
Gaseous Media ◽  
Practical Algorithm

This paper presents results of research on practical engineering solutions to suppress pressure pulsation and mechanical vibrations in piping systems. It concerns both new build and retrofitted plants. Analyses were performed according to ASME B31, EN-13480 and API 618 codes. Solutions were considered for natural gas reciprocating compressor stations (gaseous media) and liquid hydrocarbons plant with various pumps. Pressure pulsation in a piping system is a source of dynamic forces. Unbalanced pressure layout in the piping system results in the presence of dynamic forces that may excite mechanical vibrations [1,7, 22, 23, 24]. In industrial applications, mechanical vibrations are present mostly in resonant conditions. Since hundreds of eigenvalues can characterise the piping system, it is crucial to identify the key ones, which are likely to be excited to vibrate. Therefore, it is necessary to allow adequate modelling and subsequent analysis of the fluid-structure interaction with available engineering tools.

Effect of a cross-flow perforated tube on pressure pulsation and pressure loss in a reciprocating compressor piping system

2016 ◽  
Vol 231 (3) ◽  
pp. 473-484 ◽  
Author(s):  
Zhan Liu ◽  
Junming Cheng ◽  
Quanke Feng ◽  
Xiaoling Yu
Keyword(s):  
Pressure Loss ◽  
Pressure Pulsation ◽  
Cross Flow ◽  
Wave Theory ◽  
Hole Diameter ◽  
Tube Length ◽  
Maximum Deviation ◽  
Piping System ◽  
Reciprocating Compressor ◽  
Perforated Tube

This paper experimentally investigates the effects of a cross-flow perforated tube on the pressure pulsation attenuation and pressure loss in a reciprocating compressor piping network, with particular focus on the structure parameters and installation positions. The results demonstrate that significant pressure fluctuation attenuation and less pressure loss in the whole piping system can be achieved when a well-designed cross-flow perforated tube is installed downstream of the pulsating bottle. The pressure pulsation is reduced as the perforated rate decreases and as the perforated tube length increases, while the hole diameter has little effect upon the pulsation attenuation. In the aspect of reducing pressure loss, the perforated rate should be larger than 0.05 and the hole diameter should be larger than 8 mm. In addition, a pressure pulsation computation model based on the linear acoustic wave theory and transfer matrix method is developed to predict the pulsating pressure in compressor piping systems with an installed cross-flow perforated tube. With favorable agreement between the model prediction and the present experimental results (maximum deviation within 6.8%), the predicted pulsating pressure can be attenuated for the reciprocating compressor piping system with various compressor speeds when a cross-flow perforated tube is reasonably designed and installed.

Prediction of Pressure Pulsation for the Reciprocating Compressor System Using Finite Disturbance Theory

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
Bin Xu ◽  
Quanke Feng ◽  
Xiaoling Yu
Keyword(s):  
Pressure Pulsation ◽  
Nonlinear Partial Differential Equations ◽  
Piping System ◽  
Reciprocating Compressor ◽  
Pressure Pulsations ◽  
One Dimensional ◽  
Large Pressure ◽  
Finite Theory ◽  
Finite Disturbance ◽  
Excessive Noise

Pressure pulsations in the piping system of the reciprocating compressor produce excessive noise and even lead to damage in piping and machinery. Therefore, it is very important to predict precisely the pressure pulsation with large amplitude in the piping system. In this paper, the finite disturbance theory is used to solve the nonlinear partial differential equations that describe the unsteady one-dimensional compressible flow in the complex piping system. The solution is then compared with experimental results. The comparison shows that the finite theory fits the large pressure disturbance more precisely than the acoustic theory.

The Impact of Reciprocating Compressor Pulsations on the Surge Margin of Centrifugal Compressors

2017 ◽  
Vol 139 (8) ◽  
Author(s):  
Klaus Brun ◽  
Sarah Simons ◽  
Rainer Kurz
Keyword(s):  
Centrifugal Compressor ◽  
Pressure Pulsation ◽  
Piping System ◽  
Reciprocating Compressor ◽  
Centrifugal Compressors ◽  
Surge Margin ◽  
Periodic Pressure ◽  
Compressor Surge ◽  
The Impact ◽  
Asme Paper

Pressure pulsations into a centrifugal compressor can move its operating point into surge. This is concerning in pipeline stations where centrifugal compressors operate in series/parallel with reciprocating compressors. Sparks (1983, “On the Transient Interaction of Centrifugal Compressors and Their Piping Systems,” ASME Paper No. 83-GT-236); Kurz et al. (2006, “Pulsations in Centrifugal Compressor Installations,” ASME Paper No. GT2006-90700); and Brun et al. (2014, “Impact of the Piping Impedance and Acoustic Characteristics on Centrifugal Compressor Surge and Operating Range,” ASME J. Eng. Turbines Power, 137(3), p. 032603) provided predictions on the impact of periodic pressure pulsation on the behavior of a centrifugal compressor. This interaction is known as the “compressor dynamic response” (CDR) theory. Although the CDR describes the impact of the nearby piping system on the compressor surge and pulsation amplification, it has limited usefulness as a quantitative analysis tool, due to the lack of prediction tools and test data for comparison. Testing of compressor mixed operation was performed in an air loop to quantify the impact of periodic pressure pulsation from a reciprocating compressor on the surge margin (SM) of a centrifugal compressor. This data was utilized to validate predictions from Sparks’ CDR theory and Brun’s numerical approach. A 50 hp single-stage, double-acting reciprocating compressor provided inlet pulsations into a two-stage 700 hp centrifugal compressor. Tests were performed over a range of pulsation excitation amplitudes, frequencies, and pipe geometry variations to determine the impact of piping impedance and resonance responses. Results provided clear evidence that pulsations can reduce the surge margin of centrifugal compressors and that geometry of the piping system immediately upstream and downstream of a centrifugal compressor will have an impact on the surge margin reduction. Surge margin reductions of over 30% were observed for high centrifugal compressor inlet suction pulsation.

scholarly journals Operational Experience and Energy-Saving Improvements on Offshore Gas Turbine Driven Compressor Trains

1994 ◽  
Author(s):  
Arne Lynghjem ◽  
Terje Heltne
Keyword(s):  
Energy Saving ◽  
Gas Turbine ◽  
High Efficiency ◽  
Operating Conditions ◽  
Operational Experience ◽  
Correct Operation ◽  
Efficient Operation ◽  
Maintenance Program ◽  
Gas Compression ◽  
Co2 Tax

The efficient operation of offshore gas turbine driven compressor trains is becoming more and more important. With the introduction of the CO2 tax on fuelgas in Norway, the operating costs have dramatically changed. It is now necessary to focus on energy-saving operation and maintenance in order to include the influence of CO2 taxation. In the Statfjord and Gullfaks fields, the LM2500 high efficiency aeroderivative gasturbines have been in operation for several years, and the operational experience is presented and discussed here with regard to efficiency and reliability. An optimised gas turbine maintenance program has been introduced in order to obtain energy-saving and cost reduction. The problems relating to the gas compression trains are discussed with regard to energy conservation and reliability. Off design operating conditions on compressors have caused problems, both with regard to power losses and machinery safeguard control systems. Energy-saving improvements have been implemented on the compressors and the system they are working in. The reliable operation of the compressors can be put at risk by the shaft-sealing system. It is of vital importance to ensure correct operation of seal system in order to obtain safe and economical operation. Improvements to shaft-sealing systems are discussed.

"Recent Patents on the Triboelectrostatic Separation of Fly Ash"

2019 ◽  
Vol 13 ◽  
Author(s):  
Haisheng Li ◽  
Wenping Wang ◽  
Yinghua Chen ◽  
Xinxi Zhang ◽  
Chaoyong Li
Keyword(s):  
Fly Ash ◽  
Power Plants ◽  
High Efficiency ◽  
Separation Efficiency ◽  
High Reliability ◽  
Operating Conditions ◽  
Security Requirements ◽  
Unburned Carbon ◽  
Efficient Operation ◽  
Triboelectrostatic Separation

Background: The fly ash produced by coal-fired power plants is an industrial waste. The environmental pollution problems caused by fly ash have been widely of public environmental concern. As a waste of recoverable resources, it can be used in the field of building materials, agricultural fertilizers, environmental materials, new materials, etc. Unburned carbon content in fly ash has an influence on the performance of resource reuse products. Therefore, it is the key to remove unburned carbon from fly ash. As a physical method, triboelectrostatic separation technology has been widely used because of obvious advantages, such as high-efficiency, simple process, high reliability, without water resources consumption and secondary pollution. Objective: The related patents of fly ash triboelectrostatic separation had been reviewed. The structural characteristics and working principle of these patents are analyzed in detail. The results can provide some meaningful references for the improvement of separation efficiency and optimal design. Methods: Based on the comparative analysis for the latest patents related to fly ash triboelectrostatic separation, the future development is presented. Results: The patents focused on the charging efficiency and separation efficiency. Studies show that remarkable improvements have been achieved for the fly ash triboelectrostatic separation. Some patents have been used in industrial production. Conclusion: According to the current technology status, the researches related to process optimization and anti-interference ability will be beneficial to overcome the influence of operating conditions and complex environment, and meet system security requirements. The intelligent control can not only ensure the process continuity and stability, but also realize the efficient operation and management automatically. Meanwhile, the researchers should pay more attention to the resource utilization of fly ash processed by triboelectrostatic separation.

scholarly journals Instantaneous Electromagnetic Torque Components in Synchronous Motors Fed by Load-Commutated Inverters

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3223
Author(s):  
Gabriel Ekemb ◽  
Fouad Slaoui-Hasnaoui ◽  
Joseph Song-Manguelle ◽  
P. M. Lingom ◽  
Issouf Fofana
Keyword(s):  
High Efficiency ◽  
Air Gap ◽  
International Standards ◽  
Synchronous Motors ◽  
Gas Compression ◽  
Variable Frequency Drives ◽  
Torsional Analysis ◽  
Analytical Expressions ◽  
Very High ◽  
Excitation Circuit

This paper proposes time-domain analytical expressions of the instantaneous pulsating torque components in a synchronous machine air gap when supplied by a load-commutated-inverter (LCI) system. The LCI technology is one of the most used variable frequency drives when very high power and low speed are required in applications such as pipeline recompression and decompression, as well as liquefied natural gas compression. In such applications, synchronous motors are used because of their high efficiency resulting from a separated supply of the current to their rotor through the excitation circuit. These applications usually have long and flexible shafts, which are very sensitive to torsional vibration excitation when their natural frequencies interact with any external torque applied to the shaft. A torsional analysis is required by international standards to assess the survivability of the shaft through the overall speed range of the motor. Therefore, the magnitude and frequencies of the motor air-gap torque are needed for such evaluation. The proposed developments are supported by numerical simulations of LCI systems in a large range of operation range. From the simulation results, torque harmonic families are derived and expressed in a parametric form, which confirm the accuracy of the proposed relationships.

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