ApplicationSolution

INTRODUCTIONTriconex® delivered a High Integrity Pressure Protection System (HIPPS) to prevent excessive vent flow rate in the compressor trains. This system is to prevent excessive flow rate (>7.5 MM Nm3/day) to the vent system if the safety shutdown system fails to stop two compressors of a blocked outlet, at maximum capacity of 10 MM Nm3/day. Due to the criticality of the application and the associated operations this application required a high available safety system. The project was completed in 10 weeks.

PROJECT DESCRIPTIONTo ensure the high availability of the application, three analog pressure transmitters are connected to the flow line downstream on each compressor. In the event of high pressure, each pressure transmitter generates a pressure alarm (PSH) in the Mission Critical PLC. The Mission Critical PLC system (application referred to as HIPPS), stops the compressor, and initiates closure of the shutdown valve in the feed fuelgas line to the gas turbine of each compressor. As a result of this modification, the probability of failure in stopping two compressors when high pressure falls below 10-5. This improves the safety and production performance of this process.

Trident-Based Excessive Vent Flow Rate Protection System

Summary

The small Safety

Instrumented System (SIS)

package is a scalable,

small footprint, cost-

effective and highly

reliable solution based

on the Trident platform

designed for High Integrity

Pressure Protective System

(HIPPS) with low I/O point

count requirements. It

provides the availability

required to meet high

processing speed in critical

control applications.

Business Value

Triconex safety system

helps customers in

protecting their production

assets and complying with

rigorous environmental

standards; in turn

customers meet and

exceed production targets

by maintaining maximum

process uptime by safely

operating their plants.

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FUNCTIONAL DESCRIPTIONThe HIPPS PLC was built in a dedicated cabinet with an independent display unit. The Trident™ safety and critical PLC was chosen as the HIPPS PCL due to its high integrity. The compressor unit is equipped with three independent dedicated transmitters in the discharge and one dedicated dual solenoid shutdown valve in the fuelgas line.

The basic function is to close the fuelgas to the compressor, when the compressor is not responding to a stop command and the discharge pressure is building up against a closed treatment. Without HIPPS, the relief valve could remain open. If one or more compressors fail to stop the vent, the vent will flow above the maximum design flow with the potential for high emissions.

WHY TRIDENT?This application required a very high degree of safety and availability with high diagnostic coverage and the matchless reliability of a Triconex product in a small package. These attributes made the Trident solution a perfect fit for the applications.

For decades, Triconex products have been acknowledged by the end-user as the only safety and critical control system that combines safety and availability for mission critical applications. Invensys’ certified processes ensure that the required safety standards and tight project execution schedule of only 10 months where met.

Rel. 02/10

Triconex Trident