(29d) Abqaiq Plant Virtual Plant Model and RTO Implementation

Abstract

Abqaiq Plant is the largest worldwide crude stabilization plant with $200MM energy consumption per year.  Abqaiq NGL plant shares 30% of total energy consumption.  High NGL recovery rate has been the objective because of undesired loss of hydrocarbon liquid condensate in the offgas pipeline.  Recent efforts for process improvements including commissioning of TEG dehydration unit and compression train upgrades have been implemented to enhance NGL recovery and the availability of desired cryogenic cooling for C2/C3 separation. 

Abqaiq Natural gas liquid process includes three major processes: compressing, high pressure stripping and deethanizing. Simultaneous optimization for all three major processes under the constraints of NGL product spec. requires fundamental understanding and a robust simulation tool. It has been a challenge for process and control engineers to develop such a complete model which can map the plant operating conditions in situ and perform a complete plant optimization online. 

ROMeo (Rigorous Online Modeling with Equation-based Optimization), a widely used real time optimization (RTO) platform, can be used to achieve our goal. A real time optimizer can take the variations in upstream units such as changes in crude feed flow combinations and stabilization depth in real time, and calculates the most profitable mode of operating condition by using the rigorous plant model with energy consumption equations and process and product constraint equations. Then the calculated optimal set points are submitted to the DCS control room to ramp the plant process.

Abqaiq Plant NGL engineering department has successfully implemented and tested an in-house developed RTO NGL plant model. A potential increase of $200M to $400M revenue increase for each adjustment has been predicted under the current operating mode and unit operation constraints. In addition to the quantifiable revenue advantages, this presentation will also highlight other substantial advantages of the system such as measurement health monitoring, next generation process KPIs, and energy optimization.