Initial Pipe Routing Optimization for Ship Conversion

Initial Pipe Routing Optimization for Ship Conversion

Jacobse, Luuk (TU Delft Mechanical, Maritime and Materials Engineering)

Pruijn, J.F.J. (mentor)
Malikouti, Christina (mentor)

Delft University of Technology

Marine Technology | Marine Engineering

2021-07-05

In the volatile and demanding current market and in view of frequent implementation of new emission regulations, ship renovations entail more and more radical conversions of higher complexity. Application of optimization methods in the ship maintenance, repair, and conversion industry have been so far frequently overlooked, due to the former lack of need for extensive engineering.
Compared to new-build ships, in ship conversion, a leading part of the project, pipe routing, becomes particularly challenging. Existing construction of the ship and retained equipment result in a more crowded environment while existing lines are frequently extended to connect new equipment, which requires finding the optimal branching point. Operational aspects of the vessel can have an effect on both engineering of piping and defining the production areas. A clear example is that tanks may be filled during ship conversion whereby routing through tanks requires consideration of the emptying costs per m3 of the fuel and the cleaning costs of the tank per m2. All these constraints extend the pipe routing problem to more than a shortest path problem. It is a best path problem with the cost being the variable.
The present study looks into the process of pipe routing within ship conversion with goal to create a model/tool for pipe routing in a cost-effective way.
During the first steps, an investigation is performed on relevant studies, which yields that such a tool for the case of ship conversion is not yet available. Therefore, it is decided that a model is developed from scratch as a baseline cost estimation model. A thorough study of the algorithms applied in the literature study is performed to find the appropriate algorithm. It was concluded to implement the A* Algorithm on a grid.
The baseline model is created as a quasi-3D environment, where routing through multiple 2D decks is achieved with switching points. The main goal of the model is to route a single pipe from A to B within the particular pipe routing constraints and the extra factors applicable to ship conversion. The pipe routing constraints are straight pipe, flange, bends, and clamp/support costs while optimizing for the least amount of bends. The extra factors of ship conversion addressed are as follows:
• Penetration costs through existing decks and bulkheads
• Tank opening costs which are possibly filled
• Avoiding inaccessible obstacles or untouchable areas of the ship
• Routing close to wall and tank edges for the ease of installation (production constraints) within the limited space of conversion.
The verification of the model is carried out with the following tests: the verification of intermediate solution, continuity test, degeneracy test, fault injection, and the consistency check. Finally, a potential analysis is performed on the verified model to demonstrate the capabilities and limitations of the model. The cases of multiple end points, multiple pipes and bundling as well as bending optimization are examined and bring a solid picture of the baseline model capabilities and opportunities for further development.

Ship conversion
pipe routing optimization
life cycle engineering

http://resolver.tudelft.nl/uuid:d6d50466-6904-46b0-a125-5c7a6bc919c4

Student theses

master thesis

© 2021 Luuk Jacobse