Welcome to OPSEL!
We study Process Systems Engineering (PSE) in offshore units including offshore installations, mobile units and special ships.
- Definition and classification of offshore units (Korean)
(임영섭, 권도중, 이창희, 해양시설 용어 정의 및 분류 체계에 관한 일고찰, 수산해양교육연구 제29권 제3호 (통권 제87호), 689-701, 2017.6)
PSE is the answer to the question, how multiple processes behave as a whole system. To design and control process systems, we build numerical models, simulate them and optimize them.
We handle all research topics of offshore process systems on topsides.
We also handle advanced process systems required for ships, such as BOG re-liquefaction system. It's also a system!
The goal of OPSEL is to make the engineering design procedure smarter, by integration and automation of interactions between different systems considering characteristic differences in offshore engineering. In the EPC (Engineering, Procurement, and Constuction) step in an offshore project, designs are repeatedly changed to solve problems that were not expected in the beginning stage. It looks like a kind of "Feedback" design. I want to make it a kind of "Feedforward Design." to estimate major impact between system interfaces earlier. Not only the manufacturing but also the engineering design must be smarter. Of course, we cannot predict everything in actual projects from the first time, but we can predict many things from the historical data and experience, and the information at each design stage can update the accuracy of estimation step by step.
To make it smarter, we are focusing following topics:
Illuminating interfacing problems
A good question is much more important than a good answer. To solve a problem, we must understand exactly what the problem is. A lot of complexity of an offshore engineering project come from the interfacing boundary between systems, not from the inside of a system. This is because several different participating parties are enrolled in one project to combine disparate components for one platform. This structure may cause unexpected problems that causes design changes when some results are transferred from one system to another system as inputs. For an example, something in a reservoir is changed, subsea flowline may be changed. When the subsea flowline is changed, slug catcher design on the topside may be changed. The safety issues also may change topside process design. When the topside design is changed, the design of interfacing support of structure or the offshore structure itself also may be changed.
Advanced process design (feedforward engineering design)
To reduce the occurrence of the unexpected problems from the interfacing boundary between systems, an integrated system combining major points of two+ systems is required. We know that we cannot integrate all the system at the detailed level. Instead, the reduced or surrogated model can be used for the large integrated system. By using the concept of integrated design, we can approach to the feedforward design. The significant special issues will be predicted in the early detailed engineering design stage, basic engineering design (FEED) stage, and even conceptual design stage. Also, strong computation power is now making the prediction of selected options possible. We are focusing on superstructure optimization to screen the options and select better concepts.
* Related Research:
- Lifetime cycle expenditure estimation for offshore units considering availibiltiy and risk (will be updated)
- MEG regeneration process for oil fields (will be updated)
- Optimal design of BOG re-liquefaction system for LNG Carrier, LNG fueled-ship, ethane carrier, or LPG carrier (will be updated)
"Better" may mean different things case-by-case. It may be more accurate, precise, or fast-solvable model what it is required. When a model cannot explain the actual phenomena, better accuracy or reliability is required. Sometimes a model can explain well the situations but requires too long time to solve it; a reduced or surrogated model is required.
* Related Research:
- Rapid depressurization of vessels (Blowdown) and Flare system
We are focusing on superstructure optimization to screen the options efficiently. We are interested in derivative-free optimization algorithms, which are especially useful for the optimal search between different platforms without demanding expensive mathematical calculation
* Related Research:
- ORC (Organic Rankine Cycle) for FSRU
(U. Lee, J. Jeon, C. Han, Y. Lim, Superstructure based Techno-Economic Optimization of the Organic Rankine Cycle using LNG Cryogenic Energy, Energy, 137, 83-94, 2017)
- A modified sub-dividing DIRECT algorithm for hidden constraints.
(Jonggeol Na, Youngsub Lim, Chonghun Han, A modified DIRECT algorithm for hidden constraints in an LNG process optimization, Energy, 126(1), 488-500, 2017)
In actual design procedure, not short time is consumed to allocate, calculate and validate values. For offshore projects, different company requires different practices and it make the procedure complex because of different criteria for each project. The automation based on the practices can cut down these time consuming procedure. An automated interface code can help decrease the time to transfer data from one program to another program when there is no integrated platform. Sometimes, not only steady-state properties but also transient state properties are required to evaluate systems, and it requires automated evaluation of system dynamics.
* Related Research:
- Automated equipment sizing based on IOC Practices (will be updated)
- Simple graphical method for Anti-surge valve design.
(Y. Oh, C. Lee, Y. Lim, A Short-cut Graphical Method for Sizing of Recycle valves in Anti-Surge System Considering Time Delay, Journal of Process Control, 58, 23-32, 2017)