Control system for suction valves within gas compressors skids located in potentially explosive zones

Abstract

The paper presents the implementation of a feedback loop controller for the suction valves used within the gas compressors skids manufactured by Romanian Research and Development Institute for Gas Turbines COMOTI. These compressors are installed at beneficiaries, in potentially explosive environments (e.g., gas extraction and transportation applications). The proposed solution addresses the problems observed due to the high suction pressures of screw compressors, which may occur at start-up or during operation, leading to failed start-ups or emergency shutdowns. An automatic sequence implemented in the control software and displayed on the operating panel, could assist the operator during high suction pressures (above 1.2 bar). These pressure conditions normally lead to alarm limits and to performing an automatic shutdown sequence for protecting the compressor. The paper herein discusses the implementation of a start-up sequence in the programmable logic controller’s software, which can be applied without critical interventions on the compressor packages, only through minor control software modifications which can safely extend the inlet pressure range and the exploitation of the compressors. Thus, since no hardware modifications are required, we also ensure maintaining the ATEX certifications of equipment and assemblies.