Process for protecting a turbocompressor from operating in the unstable working range

Abstract

To protect a turbocompressor ( ) with a downstream process from operation in the unstable working range, a machine controller is used, which optionally contains—besides a surge limit controller ( )—an intake pressure controller ( ), an end pressure controller ( ) and a bypass controller ( ). A control matrix is determined from the position of a control unit (fuel gas control valve ) determining the flow to the process, optionally taking into account additional influencing variables such as the compressor intake pressure and the compressor discharge pressure. The necessary position of the surge limit control valve ( ) as well as of the bypass valve ( ), of the intake pressure control valve ( ) and of the actuating drive ( ) for the compressor inlet vanes ( ) is determined directly on the basis of the control matrix during a rapid transient change in the working position, and this actuating variable is directly superimposed as a manipulated variable to the surge limit control valve ( ), the intake pressure controller ( ), the end pressure controller ( ) and the bypass controller ( ).