Analyzing and Presenting New Ideas for Anti-Surge Control in Centrifugal Compressor

Abstract

Centrifugal compressors are generally used for natural gas carriage by cumulative the heaviness of the gas. Surge is an intrinsic occurrence in a centrifugal compressor, distinct as setback of fluid flow which cans perhaps impairment the machine. Anti-surge control is a vital control for protection of the compressor and it can keep the compressor always running in the benign zone right to the surge line. In this article, simulation outcomes of the surge occurrence occurring in a centrifugal compressor in different situations such as high header pressure, low suction pressure, and start-up and crisis shutdown of the unit are presented and their control policies are debated. Dynamic simulation of the centrifugal compressor is done by HYSYS. Conventional PID and Advanced (PI and over Recycle Trip) controllers are applied to check their act. Advanced controller proves to be prior to simple PID controller in shielding the compressor in plain surge case. Start-up and shut down surge was prohibited by completely opening the anti-surge control regulator. Background/Objectives: High pressure is essential for the gas to be transported to commercial and industrial zones from remote well head places through pipelines. Compressors are used for this request to raise the pressure of the gas. A complete compression procedure consists of turbo-compressor unit, scrubbers, piping, control valves and coolers1. The incoming gas is first filtered to eliminate the foreign and dust particles, then it is passed to scrubbers where liquid droplets are removed to protect compressor from liquid entry damage. The compressed gas is then passed through coolers to let the high temperature to decrease. Results: Dynamic simulation of a centrifugal compressor was carried out in HYSYS. Surge settings were simulated for high header pressure, low suction pressure, start-up and emergency shutdown of the unit. Conventional PID and Advanced (PI plus Recycle Trip) controllers were applied to check their performance to protect the compressor from surge in different scenarios. The exemplary of compression system implemented in HSYSY is shown in Figure 11.