Energy is Essential

Energy is essential to drive the production of any process. In today's competitive world, the operation must be top-of-the-line. This means the highest level of energy efficiency must be achieved.

"CWB Tech’s Utility Plant Model provided a great deal of insight into the operation of Japan Energy’s utility plant. Not only were we able to achieve a more efficient operation, but also plan effectively for future capacity increases."

Katsuyuki Sasaki
Senior Process Engineer
Mizushima Oil Refinery
Japan Energy Corporation

Total Site Modeling & Analysis

What is Total Site Analysis?

In a chemicals complex, there are many chemical plants. Some of them make the final products, whereas others make intermediate products which are consumed within the production site. All of these process plants consume energy in the form of steam or power. A utility plant generates the steam and electricity required to support the production. The demand for utilities varies with the production capacity of the various plants at the site. An additional level of interaction exists due to the possible recycle of by-products from the process plants as fuel to the utility plant. Because of the varying cost of fuel and power, and the varying utilities demand, the operation of the utility plant needs to be constantly tuned to achieve optimum operation. A Total Site Model is a linear programming based mathematical model which can model all the interactions in the utility and the production plants and capture the significant potential present here.

What can Total Site Model do for you?

A Total Site Model can be used in many ways depending on the level of detail included during the modeling. It can be used to optimize the day to day operations of the utility plant. It also serves as an invaluable tool in making strategic and long term decisions. CWB Tech’s Total Site model also provides various options for marginal cost calculation and sensitivity analysis, which can be used to do case studies and “what if” analysis. Following are some of the ways that a Total Site model can help you to achieve a higher level of performance for your utility plant and production site.

Optimize and manage utilities production

• Optimize the hourly steam and power production to minimize costs
• Optimize Boiler and Turbine loadings
• Optimize the power generated in-house versus that purchased from outside
• Maximize the use of the most efficient equipment
• Choose correct fuels in each boiler
• Reduce let-downs and venting of steam

• Where are the bottlenecks in the current utility plant, and how should the existing configuration be modified?
• How can we plan for the utilities production for today, tomorrow, or next month.
• What is the correct price of steam at various levels? How does it change with the steam demand?
• What is the impact of startup or shutdown of certain plants or equipment?

• Evaluate the economics of proposed process-efficiency or capacity improvement projects
• Enable more effective negotiations with third party independent power producers
• Enable decision making for production planning, site-wide maintenance scheduling, product pricing, and others

What is included in a Total Site Model?

A schematic of a typical utility plant and an accompanying production site is shown below. Our linear model takes into account the detailed configuration of the plants, the interactions between the production and utility sites, and all operational constraints for the individual plants and equipments.

Being custom made, there is complete flexibility on what to include in the modeling. The focus can be on on the Utility Plant, the Production Site, or both.

Pinch Analysis

CWB Tech offers the Pinch Analysis technology to our clients. We have extensive expertise in applying this analysis to various industries, oil refinery, petrochemical processes, and the like.

Based on the heat and material balance of the system, the necessary stream data will be extracted. Then the pinch diagrams, such as composite curves, grand composite curves, utility grand composite curves, etc., together with the energy target, will be determined. Most importantly, the "Pinches" and the "Cross-Pinch heat exchangers" will be identified. Further process modifications can then be suggested and implemented.

Pinch Analysis has originated from the Process Integration Department at UMIST. Since then, many significant advancements have been achieved.

Please contact us for further information regarding our services for energy savings.

Reference Publications

• K. Hirata, H. Sakamoto, K.Y. Cheung, L. O’Young, and C.W. Hui, "Simultaneous Site-Wide Energy, Waste and Production Optimization – Industrial Case Studies," European Symposium on Computer Aided Process Engineering-14, Lisbon, Portugal, A. Barbosa-Povoa and H. Matos, eds, Elsevier, Amsterdam, pp.925-930 (2004)
• K. Hirata, H. Sakamoto, L. O'Young, K. Y. Cheung, and C. W. Hui, "Multi-Site Utility integration--an Industrial Case Study," Computers & Chemical Engineering, 28, 139-148 (2004).
• K. Y. Cheung, C. W. Hui, H. Sakamoto, K. Hirata, and L. O'Young, "Short-Term Site-Wide Maintenance Scheduling," Computers & Chemical Engineering, 28, 91-102 (2004).
• K. Y. Cheung, W. K. Li, C. W. Hui, H. Sakamoto, and L. O'Young, "Universal Plant Model for Production Planning," Proceeding of the 5th Conference of Process Integration Modeling and Optimisation for Energy Saving and Pollution Reduction (PRES'02), Prague (2002).
• K. Y. Cheung, and C. W. Hui, "Total-Site Maintenance Scheduling", Proceedings of the 4th Conference on Process Integration, Modeling, and Optimization for Energy Saving and Pollution Reduction (PRES'01), Florence, Italy (2001).
• C. W. Hui, "Determining Marginal Values of Intermediate Materials and Utilities Using a Site Model", Computers & Chemical Engineering, 24(2-7), 1023 (2000).

If you would like to request a copy of any of the above papers, please Click here.