PEFTEC - Abstract

Abstract Information :

Pneumatic Controllers have been playing a vital role in conventional Production installations such as Oil Collecting Station (OCS) and Early Production Setup (EPS) of OIL since long. Crude oil collected at these installations are normally in multi phases and the primary objective of these production installations are to separate out crude oil and gas from this multi-phase stream and dispatch the separated crude oil to Tank Farm for further transport to Refineries for refining. The separated High pressure associated gas is dispatched to distribution network for marketing and low pressure gas to Gas Compressor Stations (GCS) for further compression. To achieve that objectives, pneumatically operated Pressure controllers, Level controllers and Temperature Controllers are extensively used in all these production installations.

Normally, natural gas is used as servo for the pneumatic controllers which can be easily sourced from the installation itself.

In the changing scenario of technological development, pneumatic controllers are becoming extinct like dinosaurs due to many reasons and it has been successfully replaced by ELECTRONICS CONTROLLER in association with Distributed Control System (DCS). In case of OIL, DCS based Process Monitoring and Control System (PMCS) has been utilised to monitor and control critical parameters of typical production installations. Here, electronics controller is I/P converters which successfully replaces the exiting Pneumatic controllers and directly controls the final control elements at the field based on signal receives from PMCS located at the control room. In contrast to its pneumatic counterpart, I/P based controllers integrated with PMCS gives many features which are becoming popular and gaining acceptance by users for its associated advantages.

Conventional production installations are based on old design where a sophisticated state-of the art control system with complete automation may not be viable solution as it calls for major process changes. However, I/P based Electro pneumatic controller with PMCS is a viable solution towards automation of these existing installations. This eliminates the inherent problems associated with Pneumatic controllers and at the same time, it offers the advantages of remote monitoring and control as well as other advantages associated with modern state-of-the-art facilities.

In this paper, we are trying to explain the genesis of control system used in typical production installations of OIL. The inherent problems associated with the Pneumatic control system and how the same has been successfully eliminated through I/P based PMCS system. The paper explains the critical factors in favour and against both pneumatic and electronics systems from maintenance as well as operational perspective. Comparative study of replacing existing servo system by Pneumatic Air is also explained here. Paper also explains the additional advantages associated with the DCS system in case of Gas calculation, event and alarm management, history and trend etc. after the upgradation and replacement of existing pneumatic system.