28-11-2012

Total Normandy refinery calls on ProSim to optimize its utilities production

In order to comply with the new consumption standards, Total is committed to improving its French refineries’ efficiency and competitiveness. In this context, the Normandy refinery asked Prosim to implement Ariane in its production system.

Originally, to significantly improve the production and reduce the consumption of utilities, ProSim, together with Total, developed Ariane software. The main goal was to meet the requirements in terms of optimization and to provide guidance and practical suggestions for other industries where in-house management of energy requirements (steam, electricity or hot water) is a key parameter of the production process.

The Normandy refinery project succeeded because these important three goals were achieved:
- To implement Ariane to improve the steam and electricity production efficiency on the Normandy refinery site.
- To map out carefully energy consumption and production in real-time.
- To use the model to foresee the impact on the plant production of the addition of a unit, of a device, of a turbine disruption on the plant production equilibrium.

Solution implementation
1 - Gathering information and integration of the Normandy refinery model into the software
As a first step, the ProSim engineers, together with the operators, gathered all the necessary information to map out the site’s industrial processes and to identify the degrees of freedom for the plant optimization.

2 - Software implementation
The applications implemented to work seamlessly online together are detailed below:
• On-line optimization
The project aimed at inserting the Ariane model into a larger application that automates the inputs/outputs and the ‘user’ parameters and options management. Overall, the application accounts for the recovery of upstream raw measurements and their automated processing, the detection of equipment failure and the calculation options (selection of the optimization degrees of freedom).

Model data that are not measured (parameters such as purchase and resale prices for instance) are provided by the user in the application.
After the calculations, the application archives its results and provides editable reports for the operators.

• The consumption/production consolidation
The consumption/production consolidation application of the site does not use Ariane to carry out its calculations. This application, launched upstream of the online optimization, prepares the data necessary for the optimization of:
- Consolidated steam consumptions;
- Controlled unit operations such as the turbines;
- Operation of the CONV3 unit;
- Important valves located in the unit operations, and also integrated into the whole optimization model.

• Planning
The planning application uses the refinery’s current state (results of the online consolidation calculations and of the predictive data that are provided by the operators in the unit operations) to plan, in advance, the next day’s production and to anticipate potential problems.

In the unit operations, the operators fill their production program into data files that are analyzed by the planning application in order to transform the unit operations’ loads (expressed in process throughput) into steam demand in the different refinery net-works. By compiling these results, and starting from the current operating point, the planning application is able to predict the plant production patterns over periods of time up to 72 hours.

• Reporting
The application is an exe file that can be automatically launched at a selected frequency or manually started upon demand. This executable file fills out a report with the current results (the last calculated results) of the previous three applications (consolidation of the balances, online optimization and planning). The executable file uses a Microsoft Excel file model containing the tables’ structures, the graphs and other information given with the last results of the online applications.
The following figure shows part of the results file exported for the users. This results file is a summary of the calculations done and of the recommendations proposed by the online calculator.

Conclusion
The Ariane implementation project has been successful. The convergence rates are excellent. The operator is then advised in real-time to adjust the production plant, to manage the turbines settings and to order the opening/closing of certain valves located in the unit operations. The daily report can be edited on demand to import optimal operating instructions of the plant.

In addition, implementing Ariane on-site allows a better knowledge of the refinery steam networks and of the associated economic issues. In practice, this tool:
- improves the real-time management of the internal networks by integrating them to the refinery optimization process (estimated gain of 300k€/year).
- helps to identify new energy optimization projects thanks to a better network balancing (estimated gain of 1.2 M€/project being implemented on the site). As a minimum, and on a quantitative basis validated by the operators, the total gains amount to at least 2.5% of the plant budget (steam purchase and electricity).

Since its implementation, Ariane has earned the confidence of the site operators by making efficient and realistic recommendations; those recommendations have convinced the operators of the interest in using such an optimization solution.