Surge Control System Research Articles

Cylinder-piston application for surge prevention and energy efficiency in an industrial compression unit

Compressions are prevalent in industrial applications and are notable for their substantial energy consumption. Therefore, the simulation and analysis of the compression process are essential for maintenance and energy conservation efforts. These systems are prone to potentially unstable surge conditions, necessitating the use of traditional anti-surge valves that result in considerable energy losses. Ensuring the near-optimal operation of these systems is critical to minimizing energy consumption.In this article, a conceptual framework for a cylinder-piston mechanism is delineated, intended for design and operation as an active surge control system. Additionally, a modular quasi-one-dimensional model is articulated for the transient simulation of an industrial compression system, which integrates models for both the anti-surge and active control systems. The manuscript presents a novel design, featured by a cylinder-piston system integrated with a robust controller, posited as a potential alternative to traditional anti-surge systems. The effectiveness of this design in expanding the operational envelope of the compression system and surge prevention is rigorously examined. Moreover, a thermodynamic model, grounded in the fundamental laws of mass, momentum, and energy conservation, is applied to each component of the system. Furthermore, the manuscript explores the benefits of the innovative design in achieving a marked decrease in energy wastage. Simulation results from a test scenario reveals that the implementation of the cylinder-piston design, as opposed to the conventional anti-surge system, can diminish energy losses and associated pollutant emissions by approximately 33 percent.

Development of a mathematical model to simulate a natural gas compression system and its anti-surge control to improve performance: A case study to reduce the energy consumption, and the environmental impact

Compression systems are extensively used in the petrochemical industry. They are very intensive energy consumers, and simulation and analysis of this process are vital for their better maintenance and limiting their energy consumption. Here we follow an industrial case study to model and simulate a compression loop of the petrochemical industry and show potentials for energy savings and environmental improvements In this paper we introduce a modular quasi-one-dimensional model to simulate a two-step seven-stage compressor and all components of the compression loop, including the surge control system. For each component, including pipes, separation drums, heat exchangers, and compressors, a thermodynamic model based on the mass, momentum, and energy conservation laws is obtained, then each component of the system can be presented as an independent module. By stacking all modules together, the entire compression system is modeled. Finally, a numerical simulation is performed for many different scenarios to study the behavior of the surge phenomenon, the surge control system, and especially the effects of the intentional anti-surge valve openness for extra surge margin, which results in huge energy loss and environmental impacts. This simulation shows that removing the intentional openness of the anti-surge valves will reduce about 15.8% of the CO2 emissions, and the power consumption required to run the turbine may be reduced up to 1.8 MW.

The role of shaft-speed oscillation on the instability behavior of transonic radial compressor

A dynamic model of the free-spool compression system is established to investigate the effects of rotational speeds oscillation on the surge characteristics and behaviors. Simulation results show better agreement with the experimental data compared to the fixed-spool simulation, which confirms the importance of introducing rotor dynamics into surge modeling. The mechanism of the prolonged surge cycle is presented, as well as an overall comparison and explanation of discrepancies in surge characteristics between different operating speeds and design cases. It is pointed out that the relative position of the averaged deceleration line and the surge line is critical in leading to the discrepancies. Further perturbation analysis concerning the effects on the surge limit suggests that reducing the rotational inertia of the spool may enhance the system stability under certain circumstances, which can be evaluated by the speed variation contribution parameter (SVC). The results may further contribute to the design of surge control system.

A novel tube model predictive control for surge instability in compressor system including piping acoustic

Tube model predictive control (MPC) is one of a few suitable techniques for robust stabilization of disturbed nonlinear systems subject to constraints. This paper introduces the integration of H∞ control scheme into a robust tube MPC control algorithm for surge prevention in centrifugal compressor system in the presence of bounded disturbances. Nonlinear dynamic of compression system is considered that contains acoustic of compressor system and brings up the effects of the station’s piping system on the compressor surge. Also, close-coupled valve is selected as actuator for the surge control system. The proposed method is composed of two controllers: a nominal MPC controller which solves a standard surge problem for the nominal system, and an ancillary MPC controller from H∞ control approach to stabilize the states despite disturbances. Numerical simulation results verify the capability of the proposed surge control method and guaranty the asymptotic stability of compression system in the presence of disturbances.

Active Compressor Surge Control System by Using Piston Actuation: Implementation and Experimental Results

A novel implementation and experimental test results of a piston actuated active surge control system (PAASCS) on a laboratory scale pipeline-compressor system are presented. The experimental test is done to prove the concept of stabilizing compressor surge by dissipating the plenum energy using a piston actuation. The PAASCS’s controller is applying φ-control introduced in (Uddin and Gravdahl, 2016), which only uses feedback from pressure measurements at the compressor discharge and in the plenum. Practical aspects of implementing the PAASCS are presented including: flow measurement, generating a compressor map based on a compressor performance test, piston design, and the test setup. The experimental test results show that the PAASCS is able to stabilize surge and prove the concept of PAASCS with the advantage of φ-control which stabilizes compressor surge by using feedback from pressure measurements only.

Introducing Back-up to Active Compressor Surge Control System

A novel method for introducing a back-up system to an active compressor surge control system is presented in this paper. Active surge control is a promising method for extending the compressor map towards and into the unstable area at low mass flow by stabilizing the surge phenomenon. The method also has potential for allowing operation at higher efficiencies. However, a failure in the active surge control system may endanger the compressor by entering deep surge as the compressor is allowed to operate in the stabilized surge area. We propose the use of a back-up system applied to the active system to keep the compressor safe should the active system fail. This paper present an active compressor surge control system with piston actuation combined with a blow off system as the back-up. Performance of the combined system is evaluated by simulating the system in situations where the piston is saturated or jammed. The combination results in a system with increased performance by taking advantage of both systems.

Experimental Evaluation of the Transient Behavior of a Compressor Station During Emergency Shutdowns

The transient behavior of compressor stations, particularly under rapidly changing conditions, is of vital interest to operators. Predicting transient behavior is an important factor in avoiding damage during events such as emergency shutdowns. A limited number of “accidental” data sets from compressor manufacturers and users are available in the public literature domain. A variety of simulations and modeling approaches have been presented over the last few years at industry conferences. The available experimental data is not of sufficient quality and resolution to properly compare predictions with analytical results or simulations available in current software packages. Necessary information about the compressor, driver, valves, and geometry of the system is often missing. Currently utilized software has not been adequately validated with full-scale realistic benchmark data, as this data is not available in the public domain. Modeling procedures and results of surge control system simulations seldom contain validation data achieved through actual testing. This type of transient test data for a dynamic surge condition is often difficult to obtain. The primary objective of this work is to develop experimental transient compressor surge data on a full-scale test facility, which would facilitate the verification and comparison of existing and future transient surge models. Results of the testing and model comparisons will be documented. Relevant, dimensionless parameters will be presented and validated utilizing the test data. Conclusions from the testing and recommendations for the transient analysis software will be provided.

Digital Simulation of An On-off Surge Control System in a Long Water Gravity Line

Pressure surge control may be a very difficult problem to solve in long water gravity lines. In these hydraulic systems, pressure transients are usually induced by a valve closure. Different valve stroking methods can be chosen: direct (trial and error), inverse and automatic techniques. One of the most cheap and simple control systems is the on-off controller. The basic equations and a case study are presented in this paper.