(3b) Optimum Design and Operation of Complex Steam Systems at Oil & Gas Industries through Combined Heat and Power Optimization Model

The steam and power systems in oil, gas, refining & petrochemical facilities are very complex and require optimization models to support operation to achieve required objective while meeting all constraints with the least operating cost. For the subject objective, Saudi Aramco has developed a combined heat and power (CHP) optimization model for each site. These models were found to be extremely useful in understanding the interactions between the various utility's major components. These components include boilers, cogeneration units, steam turbines, steam system network including process steam users and BFW condensate system. The interactions between these components create areas for energy optimization opportunities that lead to energy savings, GHG emission reduction and operating cost reduction. The mode considers key design and operational constraints such as: minimum steam reserve, equipment minimum and maximum operation limits as well as ensuring steam balance and energy balance is closed throughout the analysis. In addition, CHP optimization model for new design has been deployed at Saudi Aramco new facilities with energy savings benefits exceeding 10% from base case design. This paper covers several case studies addressing both operational and design improvements via utilizing the CHP optimization model, includes:

1. Design:

• Evaluating the economics of various Cogeneration options
• Evaluating the optimum sizing of a new STG

2. Operational:

• Evaluating the impact of Boilers load management
• Identifying the best combination between steam turbines and motors meeting process pumping and compression requirements with the least operating cost.