Design Considerations for High Pressure Boil-Off Gas (BOG) Centrifugal Compressors With Synchronous Motor Drives in LNG Liquefaction Plants

2019 ◽  
Author(s):  
Matt Taher ◽  
Cyrus B. Meher-Homji
Keyword(s):  
Power Factor ◽  
High Pressures ◽  
Reactive Power ◽  
Synchronous Motor ◽  
Control Mode ◽  
Centrifugal Compressors ◽  
Fuel Gas ◽  
Synchronous Motors ◽  
Design Considerations ◽  
Lng Liquefaction

Abstract The increased size of Liquefied Natural Gas (LNG) plants worldwide has led to an increase in boil-off gas (BOG) flows. The BOG can be either liquefied again to LNG or compressed to higher pressure levels for use as fuel gas. Single shaft multistage centrifugal compressors are used to compress large volume of BOG at high pressures. This paper reviews design considerations for synchronous motor driven BOG centrifugal compressors operating at high discharge pressures. Several design features including compressor selection and sizing, auxiliary system, performance characteristics and testing are reviewed. The use of leading power factor synchronous motors to improve the power factor of the LNG plant is discussed. Capability curves of API 546 synchronous motors for operation in VAR control mode — for maintaining constant reactive power — are explained. The choice between the use of speed control or adjustable guide vanes for BOG compressors is discussed.

Matching of Synchronous Motors and Centrifugal Compressors: Oil and Gas Industry Practice

2020 ◽  
Author(s):  
Matt Taher ◽  
Dragan Ristanovic ◽  
Cyrus Meher-Homji ◽  
Pradeep Pillai
Keyword(s):  
Centrifugal Compressor ◽  
Oil And Gas ◽  
Reactive Power ◽  
Oil And Gas Industry ◽  
Synchronous Motor ◽  
Variable Frequency ◽  
Centrifugal Compressors ◽  
Gas Industry ◽  
Variable Frequency Drive ◽  
Synchronous Motors

Abstract Synchronous motor driven centrifugal compressors are widely used in the oil and gas industry. In evaluating the optimum selection of synchronous motor drivers for centrifugal compressors, it is important to understand the factors influencing a proper match for a centrifugal compressor and its synchronous motor driver. The buyer should specify process requirements and define possible operating scenarios for the entire life of the motor driven centrifugal compressor train. The compressor designer will use the buyer-specified process conditions to model the aerothermodynamic behavior of the compressor and characterize its performance. Performance, controllability, starting capabilities as well as the optimum power margin required for a future-oriented design must also be considered. This paper reviews the criteria for evaluating the optimal combination of a centrifugal compressor and its synchronous motor driver as an integral package. It also addresses API standard requirements on synchronous motor driven centrifugal compressors. Design considerations for optimal selection and proper sizing of compressor drivers include large starting torque requirements to enable compressor start from settle-out conditions and to prevent flaring are addressed. Start-up capabilities of the motor driver can significantly impact the reliability and operability of the compressor train. API 617 on centrifugal compressors refers to API 546 for synchronous motor drivers. In this paper, requirements of API 617 and 546 are reviewed and several important design and sizing requirements are presented. In the effort to optimize plant design, and maintain the performance requirements, the paper discusses optimization options, such as direct on-line starting method to explore the motor rating limits, and the use of synchronous motors for power factor correction to eliminate or reduce the need for reactive power compensation by capacitor banks. This paper presents a novel approach to show constant reactive power lines on traditional V curves. It also complements capability curves of synchronous motors with lines of constant efficiency. The paper discusses variable frequency drive options currently used for synchronous motors in compressor applications. The paper addresses the available variable frequency drive types, their impact on the electrical grid, and motor design considerations with a view to summarizing factors important to the selection of variable frequency drives.

scholarly journals A Simulation Study on Controlling Excitation Current of Synchronous Motor and Reactive Power Compensation via PSO Based PID and PID Controllers

2018 ◽  
pp. 103-110
Author(s):  
Ahmet Gani ◽  
Hakan Acikgoz ◽  
Okkes Fatih Kececioglu ◽  
Erdal Kilic ◽  
Mustafa Sekkeli
Keyword(s):  
Power Systems ◽  
Power System ◽  
Power Factor ◽  
Reactive Power ◽  
Synchronous Motor ◽  
Reactive Power Compensation ◽  
Pid Controllers ◽  
Excitation Current ◽  
Industrial Facilities ◽  
Synchronous Motors

The increasing need for energy requires using existing energy sources more efficiently. Because it is the active power that supplies useful power for industrial facilities, reactive power must be minimized, and supplied by another source instead of electrical grid. Therefore, reactive power supplied by the grid can be reduced via by correcting power factor of the grid. In electrical power systems, power factor correction is called reactive power compensation. Generating reactive power during excessive excitation, synchronous motors are used as dynamic compensators in power systems. Synchronous motors are more cost-effective for industrial facilities when they are used to generate mechanic power and compensate reactive power, which increases the efficiency of industrial facilities. There are various studies focusing on the efficiency, capacity and stability of the power system via reactive power compensation in the literature. In today's world, there are numerous optimization techniques inspired by biological systems. One of these techniques is Particle Swarm Optimization (PSO) inspired by the movements of swarms of birds. This study focuses on the reactive power compensation of a power system by controlling the excitation current of a synchronous motor via PSO based PID and Ziegler Nichols (Z-N) based PID controllers.

Large Synchronous Motors as Drivers for Centrifugal Compressors in LNG Liquefaction Plants

2020 ◽  
Vol 56 (6) ◽  
pp. 6083-6093
Author(s):  
Dragan Ristanovic ◽  
Matt Taher ◽  
Thorsten Getschmann ◽  
Neeraj Bhatia
Keyword(s):  
Centrifugal Compressors ◽  
Synchronous Motors ◽  
Lng Liquefaction

Analysis of In-Plant Power Supply Load Center with Powerful Synchronous Motors and Generators of Industrial Power Station

2014 ◽  
Vol 698 ◽  
pp. 90-94
Author(s):  
Gennady Petrovich Kornilov ◽  
Timur Rifkatovich Khramshin ◽  
Ildar Ravil’evich Abdulveleev
Keyword(s):  
Power Supply ◽  
Reactive Power ◽  
Synchronous Motor ◽  
Experimental Investigations ◽  
Synchronous Motors ◽  
Computer Based ◽  
Motor Operation ◽  
Technical Solutions ◽  
Plant Power ◽  
Load Center

The research group analyzed the power supply scheme of the in-plant power supply load center and carried out experimental investigations of voltage levels and reactive power flows in this center. Start and stability of the synchronous motor operation in various operation modes and line patterns were studied using a computer-based mathematical model. Technical solutions offered in the paper will provide an opportunity to reduce the synchronous motor downtime caused by voltage reduction in the mains.

Unity power factor control of permanent magnet synchronous motor by using open winding configuration

2020 ◽  
Vol 64 (1-4) ◽  
pp. 1295-1303
Author(s):  
Dezhi Chen ◽  
Chengwu Diao ◽  
Zhiyu Feng ◽  
Shichong Zhang ◽  
Wenliang Zhao
Keyword(s):  
Permanent Magnet ◽  
Power Factor ◽  
Reactive Power ◽  
Permanent Magnet Synchronous Motor ◽  
Synchronous Motor ◽  
Unity Power Factor ◽  
Collaborative Simulation ◽  
Terminal Voltage ◽  
Vector Modulation ◽  
Power Factor Control

This paper presents the performance of open-winding permanent magnet synchronous motor (OW-PMSM). It mainly includes vector modulation technology considering the unity power factor control.And a topology structure is proposed to optimize the fault tolerance of inverter. Matlab software and Maxwell software collaborative simulation are supplied to obtain the reactive power, speed, terminal voltage, electromagnetic torque etc. under normal and fault status. Finally, the simulation results of an open-winding permanent magnet synchronous motor are verified by the experimental results.

scholarly journals SIMULATION OF REACTIVE POWER COMPENSATION OF SYNCHRONOUS MOTOR

2021 ◽  
Author(s):  
Denis Barabanov ◽  
Aleksandr Pugachev
Keyword(s):  
Power Factor ◽  
Reactive Power ◽  
Synchronous Motor ◽  
Reactive Power Compensation ◽  
Matlab Simulink ◽  
Transient Mode ◽  
Simulation Results

Simulation results of electromagnetic and electromechanical processes of 8.1 kW synchronous motor in transient mode are presented. Simulation was carried out by means of Matlab Simulink for the motor with feedback on power factor to provide compensation of reactive power.

The Design of Dynamic Reactive Power Compensation Device on Segmented Control Mode

2013 ◽  
Vol 321-324 ◽  
pp. 1333-1336
Author(s):  
Xiu He Lu ◽  
Chang Shuo Li ◽  
Qi Lin Li
Keyword(s):  
Power Factor ◽  
Reactive Power ◽  
Perceptual Load ◽  
Control Method ◽  
Metallurgical Industry ◽  
Reactive Power Compensation ◽  
Control Mode ◽  
Loop Control ◽  
Distribution Station ◽  
Compensation Device

For metallurgical industry perceptual load fluctuations large, and distribution station bus power factor low, and power loss high problems, based on reactive power compensation principle of apparent power does not variable, and used SVC structure forms, has made sectional type compensation control mode, and based on power factor of closed-loop control method, has researched the dynamic reactive power compensation device, by the check of practical run, the feasibility has been proved of the control method, and it has a clear compensation effect and wide practical range and other outstanding features.

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